Science.gov

Sample records for active flap motions

  1. Localized, Non-Harmonic Active Flap Motions for Low Frequency In-Plane Rotor Noise Reduction

    NASA Technical Reports Server (NTRS)

    Sim, Ben W.; Potsdam, Mark; Kitaplioglu, Cahit; LeMasurier, Philip; Lorber, Peter; Andrews, Joseph

    2012-01-01

    A first-of-its-kind demonstration of the use of localized, non-harmonic active flap motions, for suppressing low frequency, in-plane rotor noise, is reported in this paper. Operational feasibility is verified via testing of the full-scale AATD/Sikorsky/UTRC active flap demonstration rotor in the NFAC's 40- by 80-Foot anechoic wind tunnel. Effectiveness of using localized, non-harmonic active flap motions are compared to conventional four-per-rev harmonic flap motions, and also active flap motions derived from closed-loop acoustics implementations. All three approaches resulted in approximately the same noise reductions over an in-plane three-by-three microphone array installed forward and near in-plane of the rotor in the nearfield. It is also reported that using an active flap in this localized, non-harmonic manner, resulted in no more that 2% rotor performance penalty, but had the tendency to incur higher hub vibration levels.

  2. Forward flight of swallowtail butterfly with simple flapping motion.

    PubMed

    Tanaka, Hiroto; Shimoyama, Isao

    2010-06-01

    Unlike other flying insects, the wing motion of swallowtail butterflies is basically limited to flapping because their fore wings partly overlap their hind wings, structurally restricting the feathering needed for active control of aerodynamic force. Hence, it can be hypothesized that the flight of swallowtail butterflies is realized with simple flapping, requiring little feedback control of the feathering angle. To verify this hypothesis, we fabricated an artificial butterfly mimicking the wing motion and wing shape of a swallowtail butterfly and analyzed its flights using images taken with a high-speed video camera. The results demonstrated that stable forward flight could be realized without active feathering or feedback control of the wing motion. During the flights, the artificial butterfly's body moved up and down passively in synchronization with the flapping, and the artificial butterfly followed an undulating flight trajectory like an actual swallowtail butterfly. Without feedback control of the wing motion, the body movement is directly affected by change of aerodynamic force due to the wing deformation; the degree of deformation was determined by the wing venation. Unlike a veinless wing, a mimic wing with veins generated a much higher lift coefficient during the flapping flight than in a steady flow due to the large body motion.

  3. Flapping locomotion of a flexible wing with heaving motion

    NASA Astrophysics Data System (ADS)

    Im, Sunghyuk; Sung, Hyung Jin

    2015-11-01

    The flapping locomotion of a freely heaving flexible wing was experimentally explored in a merry-go-round equipment. Two rectangular wings were attached at the both ends of a horizontal support bar submerged in a dodecagonal water tank. The center of the support bar was connected to the vertically flapping axis which is freely rotating. This experimental apparatus generated a pure heaving motion in the vertical direction to the flapping wings in the frequency range of 0 to 5 Hz. The propulsion due to the heaving wing was expressed by a horizontally rotating speed of the support bar. The heaving motion and the rotating speed were retained with a laser displacement sensor and a rotary encoder. The rotating speed according to the heaving frequency was measured with different experimental parameters. Compared to a rigid wing, the flexible wing in the heaving motion showed a better propulsive performance in some conditions. The effects of the flexibility, the aspect ratio, and the thickness of the heaving wing on the propulsive performance were examined. This work was supported by the Creative Research Initiatives (No. 2015-001828) program of the National Research Foundation of Korea (MSIP).

  4. Current sheet flapping motions in the tailward flow of magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Wu, Mingyu; Lu, Quanming; Volwerk, Martin; Vörös, Zoltán.; Ma, Xuanye; Wang, Shui

    2016-08-01

    The feature and origin of current sheet flapping motions are one of most interesting issues of magnetospheric dynamics. In this paper we report the flapping motion of the current sheet detected in the tailward flow of a magnetic reconnection event on 7 February 2009. This flapping motion with frequency about 12 mHz was accompanied by magnetic turbulence. The observations by the tail-elongated fleet of five Time History of Events and Macroscale Interactions during Substorms probes indicate that these flapping oscillations were rather confined within the tailward flow than were due to a global process. This flapping motion could be due to the instability driven by the free energy associated with the ion temperature anisotropy in the tailward flow. Our observations indicate that the flapping motion in the tailward flow could have a different generation mechanism with that in the earthward flow.

  5. Experimental Study of Ground Effect on Three-Dimensional Insect-Like Flapping Motion

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohu; Lua, Kim Boon; Chang, Rong; Lim, Tee Tai; Yeo, Khoon Seng

    2014-11-01

    This paper focuses on an experimental investigation aimed at evaluating the aerodynamics force characteristics of three-dimensional (3D) insect-like flapping motion in the vicinity of ground. The purpose is to establish whether flapping wing insects can derive aerodynamic benefit from ground effect similar to that experienced by a fixed wing aircraft. To evaluate this, force measurements were conducted in a large water tank using a 3D flapping mechanism capable of executing various insect flapping motions. Here, we focus on three types of flapping motions, namely simple harmonic flapping motion, hawkmoth-like hovering motion and fruitfly-like hovering motion, and two types of wing planforms (i.e. hawkmoth-like wing and fruitfly-like wing). Results show that hawkmoth-like wing executing simple harmonic flapping motion produces average lift to drag ratio (\\bar C\\bar L/\\bar C\\bar D) similar to that of fruitfly wing executing the same motion. In both cases, they are relatively independent of the wing distance from the ground. On the other hand, a hawkmoth wing executing hawkmoth flapping motion produces (\\bar C\\bar L/\\bar C\\bar D) characteristic different from that of fruitfly wing executing fruitfly motion. While the (\\bar C\\bar L/\\bar C\\bar D) value of the former is a function of the wing distance from the ground, the latter is minimally affected by ground effect. Unlike fixed wing aerodynamics, all the flapping wing cases considered here do not show a monotonic increase in (\\bar C\\bar L/\\bar C\\bar D) with decreasing wing distance from the ground.

  6. Development of Bird-like Micro Aerial Vehicle with Flapping and Feathering Wing Motions

    NASA Astrophysics Data System (ADS)

    Maglasang, Jonathan; Goto, Norihiro; Isogai, Koji

    To investigate the feasibility of a highly efficient flapping system capable of avian maneuvers, such as rapid takeoff, hover and gliding, a full scale bird-like (ornithopter) flapping-wing micro aerial vehicle (MAV) shaped and patterned after a typical pigeon (Columba livia) has been designed and constructed. Both numerical and experimental methods have been used in the development of this vehicle. This flapping-wing micro aerial vehicle utilizes both the flapping and feathering motions of an avian wing by employing a novel flapping-feathering mechanism, which has been synthesized and constructed so as to best describe the properly coordinated flapping and feathering wing motions at phase angle difference of 90° in a horizontal steady level flight condition. This design allows high flapping and feathering amplitudes and is configurable for asymmetric wing motions which are desirable in high-speed flapping flight and maneuvering. The preliminary results indicate its viability as a practical and an efficient flapping-wing micro aerial vehicle.

  7. The current sheet tiled and non-adiabatic ions effect on the flapping motion in magnetotail

    NASA Astrophysics Data System (ADS)

    Wei, XinHua

    2016-04-01

    The current sheet is a crucial region of the magnetotail, where energy reserve and release take place. The origin of the up-down motions of the current sheet, referred to as flapping motions, is among the most fundamental issues of magnetotail dynamics. Observational evidences suggest that the flapping motion is a kind of internal excited kink-like waves, but its particular propagating features such as the low phase speeds and the propagating direction from the tail center toward flanks do not match any local generation mechanisms previously established so far. Here we report observations of the current sheet flapping motions induced by non-adiabatic ions in the magnetic field configurations with a finite guiding component, whose population present periodic hemispherical asymmetries. These flapping motion current sheet cases often observed tiled. The current sheet flapping phenomenon implies that the excitation mechanism of the current sheet flapping motions is a self-circulation process between the non-adiabatic ion population and the current sheet equilibrium itself.

  8. Flapping current sheet motions in magnetotail excited by non-adiabatic ions: case study

    NASA Astrophysics Data System (ADS)

    Wei, X., Jr.

    2015-12-01

    The current sheet is a crucial region of the magnetotail, where energy reserve and release take place. The origin of the up-down motions of the current sheet, referred to as flapping motions, is among the most fundamental issues of magnetotail dynamics. Observational evidences suggest that the flapping motion is a kind of internal excited kink-like waves, but its particular propagating features such as the low phase speeds and the propagating direction from the tail center toward flanks do not match any local generation mechanisms previously established so far. Here we report observations of the current sheet flapping motions induced by non-adiabatic ions in the magnetic field configurations with a finite guiding component, whose population present periodic hemispherical asymmetries. Three type of current sheet flapping event in this paper will be discussed. This current sheet flapping phenomenon implies that the excitation mechanism of the current sheet flapping motions is a self-circulation process between the non-adiabatic ion population and the current sheet equilibrium itself.

  9. Flap motion of helicopter rotors with novel, dynamic stall model

    NASA Astrophysics Data System (ADS)

    Han, Wei; Liu, Jie; Liu, Chun; Chen, Lei; Su, Xichao; Zhao, Peng

    2016-07-01

    In this paper, a nonlinear flapping equation for large inflow angles and flap angles is established by analyzing the aerodynamics of helicopter blade elements. In order to obtain a generalized flap equation, the Snel stall model was first applied to determine the lift coefficient of the helicopter rotor. A simulation experiment for specific airfoils was then conducted to verify the effectiveness of the Snel stall model as it applies to helicopters. Results show that the model requires no extraneous parameters compared to the traditional stall model and is highly accurate and practically applicable. Based on the model, the relationship between the flapping angle and the angle of attack was analyzed, as well as the advance ratio under the dynamic stall state.

  10. Role of induced vortex interaction in a semi-active flapping foil based energy harvester

    NASA Astrophysics Data System (ADS)

    Wu, J.; Chen, Y. L.; Zhao, N.

    2015-09-01

    The role of induced vortex interaction in a semi-active flapping foil based energy harvester is numerically examined in this work. A NACA0015 airfoil, which acts as an energy harvester, is placed in a two-dimensional laminar flow. It performs an imposed pitching motion that subsequently leads to a plunging motion. Two auxiliary smaller foils, which rotate about their centers, are arranged above and below the flapping foil, respectively. As a consequence, the vortex interaction between the flapping foil and the rotating foil is induced. At a Reynolds number of 1100 and the position of the pitching axis at one-third chord, the effects of the distance between two auxiliary foils, the phase difference between the rotating motion and the pitching motion as well as the frequency of pitching motion on the power extraction performance are systematically investigated. It is found that compared to the single flapping foil, the efficiency improvement of overall power extraction for the flapping foil with two auxiliary foils can be achieved. Based on the numerical analysis, it is indicated that the enhanced power extraction, which is caused by the increased lift force, thanks to the induced vortex interaction, directly benefits the efficiency enhancement.

  11. Flap-lag equations of motion of rigid, articulated rotor blades with three hinge sequences

    NASA Technical Reports Server (NTRS)

    Chen, Robert T. N.

    1987-01-01

    A derivation of coupled flap-lag equations of motion for a rigid articulated rotor with hinge springs and viscous dampers is reported. Three different flapping-lag-pitch hinge sequences are considered and the Lagrange method is used to derive the equations. The effects of the complete six degrees-of-freedom aircraft motions are included and all the inertia dynamic terms are retained; no small-angle assumptions are used in the development. Comparisons of the results with those available in the literature are made. Sources of terms missing in previous analyses, especially those of the inertia dynamics, are identified.

  12. Power performance optimization and loads alleviation with active flaps using individual flap control

    NASA Astrophysics Data System (ADS)

    Pettas, Vasilis; Barlas, Thanasis; Gertz, Drew; Madsen, Helge A.

    2016-09-01

    The present article investigates the potential of Active Trailing Edge Flaps (ATEF) in terms of increase in annual energy production (AEP) as well as reduction of fatigue loads. The basis for this study is the DTU 10 MW Reference Wind Turbine (RWT) simulated using the aeroelastic code HAWC2. In an industrial-oriented manner the baseline rotor is upscaled by 5% and the ATEFs are implemented in the outer 30% of the blades. The flap system is kept simple and robust with a single flap section and control with wind speed, rotor azimuth, root bending moments and angle of attack in flap's mid-section being the sensor inputs. The AEP is increased due to the upscaling but also further due to the flap system while the fatigue loads in components of interest (blade, tower, nacelle and main bearing) are reduced close to the level of the original turbine. The aim of this study is to demonstrate a simple and applicable method that can be a technology enabler for rotor upscaling and lowering cost of energy.

  13. Active Control of a Flapping Wing in a Gust Setup

    NASA Astrophysics Data System (ADS)

    Wallace, Ryan; Anderson, Mark; Glauser, Mark

    2006-11-01

    The aim of this experiment is to determine the response of a flapping Micro Air Vehicle wing to a wind gust while in forward and hovering flight and apply an active control to respond to the wind gust. The flapping wing is driven by a DC brushless motor which is geared to allow for flapping at frequencies up to 3 Hz. The wing is set up vertically in the wind tunnel, and can flap up to angles of 120 degrees. To simulate a wind gust perpendicular to the free stream flow a diffuser is set up on top of the wind tunnel. Strain gages are attached to the wing. It has been shown while simultaneously measuring the dynamical strain and the velocity field with a PIV system, that a realistic estimate of the wake flow field can obtained using low dimensional tools (POD, mLSE). The wing and the flapping mechanism are mounted directly on a force balance to calculate the lift being produced. In order to prevent flow separation on the wing during a sudden wind gust the wing is actively deformed by an attached piezoelectric actuator. The end result is to have closed loop control to produce stable hovering and forward flight.

  14. Pectoralis Muscle Flap Repair Reduces Paradoxical Motion of the Chest Wall in Complex Sternal Wound Dehiscence

    PubMed Central

    Zeitani, Jacob; Russo, Marco; Pompeo, Eugenio; Sergiacomi, Gian Luigi; Chiariello, Luigi

    2016-01-01

    Background The aim of the study was to test the hypothesis that in patients with chronic complex sternum dehiscence, the use of muscle flap repair minimizes the occurrence of paradoxical motion of the chest wall (CWPM) when compared to sternal rewiring, eventually leading to better respiratory function and clinical outcomes during follow-up. Methods In a propensity score matching analysis, out of 94 patients who underwent sternal reconstruction, 20 patients were selected: 10 patients underwent sternal reconstruction with bilateral pectoralis muscle flaps (group 1) and 10 underwent sternal rewiring (group 2). Eligibility criteria included the presence of hemisternum diastases associated with multiple (≥3) bone fractures and radiologic evidence of synchronous chest wall motion (CWSM). We compared radiologically assessed (volumetric computed tomography) ventilatory mechanic indices such as single lung and global vital capacity (VC), diaphragm excursion, synchronous and paradoxical chest wall motion. Results Follow-up was 100% complete (mean 85±24 months). CWPM was inversely correlated with single lung VC (Spearman R=−0.72, p=0.0003), global VC (R=−0.51, p=0.02) and diaphragm excursion (R=−0.80, p=0.0003), whereas it proved directly correlated with dyspnea grade (Spearman R=0.51, p=0.02) and pain (R=0.59, p=0.005). Mean CWPM and single lung VC were both better in group 1, whereas there was no difference in CWSM, diaphragm excursion and global VC. Conclusion Our study suggests that in patients with complex chronic sternal dehiscence, pectoralis muscle flap reconstruction guarantees lower CWPM and greater single-lung VC when compared with sternal rewiring and it is associated with better clinical outcomes with less pain and dyspnea. PMID:27733997

  15. Active Flow Control of Lifting Surface With Flap-Current Activities and Future Directions

    NASA Technical Reports Server (NTRS)

    Ahmadi, G.; Marzocca, P.; Jha, R.; Alstorm, B.; Obied, S.; Kabir, P.; Shahrabi, A.

    2010-01-01

    The main objective is to develop effective control strategies for separation control of an airfoil with a single hinge flap. The specific objectives are: Develop an active control architecture for flow control around an airfoil with flap. Design, fabricate, a wind tunnel test of a high lift wing (with flap) with integrated actuators and sensors. Design, development and fabrication of synthetic jet actuators. Develop appropriate control strategy for application to the airfoil. Wind tunnel testing of the high lift wing at various angles of attack and flap positions with closed loop control.

  16. Correlation between vortex structures and unsteady loads for flapping motion in hover

    NASA Astrophysics Data System (ADS)

    Jardin, Thierry; Chatellier, Ludovic; Farcy, Alain; David, Laurent

    2009-10-01

    During the past decade, efforts were made to develop a new generation of unmanned aircrafts, qualified as Micro-Air Vehicles. The particularity of these systems resides in their maximum dimension limited to 15 cm, which, in terms of aerodynamics, corresponds to low Reynolds number flows ( Re ≈ 102 to 104). At low Reynolds number, the concept of flapping wings seems to be an interesting alternative to the conventional fixed and rotary wings. Despite the fact that this concept may lead to enhanced lift forces and efficiency ratios, it allows hovering coupled with a low-noise generation. Previous studies (Dickinson et al. in Science 284:1954-1960, 1999) revealed that the flow engendered by flapping wings is highly vortical and unsteady, inducing significant temporal variations of the loads experienced by the airfoil. In order to enhance the aerodynamic performance of such flapping wings, it is essential to give further insight into the loads generating mechanisms by correlating the spatial and temporal evolution of the vortical structures together with the time-dependent lift and drag. In this paper, Time Resolved Particle Image Velocimetry is used as a basis to evaluate both unsteady forces and vortical structures generated by an airfoil undergoing complex motion (i.e. asymmetric flapping flight), through the momentum equation approach and a multidimensional wavelet-like vortex parameterization method, respectively. The momentum equation approach relies on the integration of flow variables inside and around a control volume surrounding the airfoil (Noca et al. in J Fluids Struct 11:345-350, 1997; Unal et al. in J Fluids Struct 11:965-971, 1997). Besides the direct link performed between the flow behavior and the force mechanisms, the load characterization is here non-intrusive and specifically convenient for flapping flight studies thanks to its low Reynolds flows’ sensitivity and adaptability to moving bodies. Results are supported by a vortex parameterization

  17. Aeroelastic stability of coupled flap-lag motion of hingeless helicopter blades at arbitrary advance ratios

    NASA Technical Reports Server (NTRS)

    Friedmann, P.; Silverthorn, L. J.

    1974-01-01

    Equations for large amplitude coupled flap-lag motion of a hingeless elastic helicopter blade in forward flight are derived. Only a torsionally rigid blade excited by quasi-steady aerodynamic loads is considered. The effects of reversed flow together with some new terms due to radial flow are included. Using Galerkin's method the spatial dependence is eliminated and the equations are linearized about a suitable equilibrium position. The resulting system of homogeneous periodic equations is solved using multivariable Floquet-Liapunov theory, and the transition matrix at the end of the period is evaluated by two separate methods. Computational efficiency of the two numerical methods is compared. Results illustrating the effects of forward flight and various important blade parameters on the stability boundaries are presented.

  18. Thrust Enhancement of Flapping Wings in Tandem and Biplane Configurations by Pure Plunging Motion

    NASA Astrophysics Data System (ADS)

    Yilmaz, S. Banu; Sahin, Mehmet; Unal, M. Fevzi

    2012-11-01

    The propulsion performance of flapping NACA0012 airfoils undergoing harmonic plunging motion in tandem and biplane wing configurations is investigated numerically. An unstructured finite volume solver based on Arbitrary Lagrangian-Eulerian formulation is utilized in order to solve the incompressible unsteady Navier-Stokes equations. Four different tandem and four different biplane wing combinations are considered. Various instantaneous and time-averaged aerodynamic parameters including lift and drag coefficients, vorticity contours and streamlines are calculated for each case and compared with each other. As a reference the single wing case corresponding to the deflected jet phenomenon in Jones and Platzer (Exp. Fluids 46:799-810, 2009) is also studied. In these simulations, the Reynolds number is chosen as 252, the reduced frequency of plunging motion (k = 2 πf /U∞) is 12.3 and the plunge amplitude non-dimensionalized with respect to chord is 0.12. The solutions of the single wing case indicate dependence on the location of start-up vortices. Meanwhile the multiple wing configurations indicate that the highest thrust enhancement is obtained in one of the biplane cases where the two wings closely moving towards each other namely biplane asynchronous-closer case.

  19. A Single Amino Acid Difference between Mouse and Human 5-Lipoxygenase Activating Protein (FLAP) Explains the Speciation and Differential Pharmacology of Novel FLAP Inhibitors.

    PubMed

    Blevitt, Jonathan M; Hack, Michael D; Herman, Krystal; Chang, Leon; Keith, John M; Mirzadegan, Tara; Rao, Navin L; Lebsack, Alec D; Milla, Marcos E

    2016-06-10

    5-Lipoxygenase activating protein (FLAP) plays a critical role in the metabolism of arachidonic acid to leukotriene A4, the precursor to the potent pro-inflammatory mediators leukotriene B4 and leukotriene C4 Studies with small molecule inhibitors of FLAP have led to the discovery of a drug binding pocket on the protein surface, and several pharmaceutical companies have developed compounds and performed clinical trials. Crystallographic studies and mutational analyses have contributed to a general understanding of compound binding modes. During our own efforts, we identified two unique chemical series. One series demonstrated strong inhibition of human FLAP but differential pharmacology across species and was completely inactive in assays with mouse or rat FLAP. The other series was active across rodent FLAP, as well as human and dog FLAP. Comparison of rodent and human FLAP amino acid sequences together with an analysis of a published crystal structure led to the identification of amino acid residue 24 in the floor of the putative binding pocket as a likely candidate for the observed speciation. On that basis, we tested compounds for binding to human G24A and mouse A24G FLAP mutant variants and compared the data to that generated for wild type human and mouse FLAP. These studies confirmed that a single amino acid mutation was sufficient to reverse the speciation observed in wild type FLAP. In addition, a PK/PD method was established in canines to enable preclinical profiling of mouse-inactive compounds. PMID:27129215

  20. A Single Amino Acid Difference between Mouse and Human 5-Lipoxygenase Activating Protein (FLAP) Explains the Speciation and Differential Pharmacology of Novel FLAP Inhibitors.

    PubMed

    Blevitt, Jonathan M; Hack, Michael D; Herman, Krystal; Chang, Leon; Keith, John M; Mirzadegan, Tara; Rao, Navin L; Lebsack, Alec D; Milla, Marcos E

    2016-06-10

    5-Lipoxygenase activating protein (FLAP) plays a critical role in the metabolism of arachidonic acid to leukotriene A4, the precursor to the potent pro-inflammatory mediators leukotriene B4 and leukotriene C4 Studies with small molecule inhibitors of FLAP have led to the discovery of a drug binding pocket on the protein surface, and several pharmaceutical companies have developed compounds and performed clinical trials. Crystallographic studies and mutational analyses have contributed to a general understanding of compound binding modes. During our own efforts, we identified two unique chemical series. One series demonstrated strong inhibition of human FLAP but differential pharmacology across species and was completely inactive in assays with mouse or rat FLAP. The other series was active across rodent FLAP, as well as human and dog FLAP. Comparison of rodent and human FLAP amino acid sequences together with an analysis of a published crystal structure led to the identification of amino acid residue 24 in the floor of the putative binding pocket as a likely candidate for the observed speciation. On that basis, we tested compounds for binding to human G24A and mouse A24G FLAP mutant variants and compared the data to that generated for wild type human and mouse FLAP. These studies confirmed that a single amino acid mutation was sufficient to reverse the speciation observed in wild type FLAP. In addition, a PK/PD method was established in canines to enable preclinical profiling of mouse-inactive compounds.

  1. Enhanced Correlation of SMART Active Flap Rotor Loads

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi

    2011-01-01

    This is a follow-on study to a 2010 correlation effort. Measured data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. As background, during the wind tunnel test, unexpectedly high inboard loads were encountered, and it was hypothesized at that time that due to changes in the flexbeams over the years, the flexbeam properties used in the analysis needed updating. Boeing Mesa, recently updated these properties. This correlation study uses the updated flexbeam properties. Compared to earlier studies, the following two enhancements are implemented: i) the inboard loads (pitchcase and flexbeam loads) correlation is included for the first time (reliable prediction of the inboard loads is a prerequisite for any future anticipated flight-testing); ii) the number of blade modes is increased to better capture the flap dynamics and the pitchcase-flexbeam dynamics. Also, aerodynamically, both the rolled-up wake model and the more complex, multiple trailer wake model are used, with the latter slightly improving the blade chordwise moment correlation. This sensitivity to the wake model indicates that CFD is needed. Three high-speed experimental cases, one uncontrolled free flap case and two commanded flap cases, are considered. The two commanded flap cases include a 2o flap deflection at 5P case and a 0o flap deflection case. For the free flap case, selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the commanded 2o flap case, the experimental flap variation is approximately matched by increasing the analytical flap hinge stiffness. This increased flap hinge stiffness is retained for the commanded 0o flap case also, which is treated as a free flap case, but with larger flap hinge stiffness. The change in the mid-span and outboard loads correlation due to the updating of the flexbeam properties is not significant. Increasing the number of blade modes results in an

  2. Active Control of Separation From the Flap of a Supercritical Airfoil

    NASA Technical Reports Server (NTRS)

    Melton, La Tunia Pack; Yao, Chung-Sheng; Seifert, Avi

    2003-01-01

    Active flow control in the form of periodic zero-mass-flux excitation was applied at several regions on the leading edge and trailing edge flaps of a simplified high-lift system t o delay flow separation. The NASA Energy Efficient Transport (EET) supercritical airfoil was equipped with a 15% chord simply hinged leading edge flap and a 25% chord simply hinged trailing edge flap. Detailed flow features were measured in an attempt to identify optimal actuator placement. The measurements included steady and unsteady model and tunnel wall pressures, wake surveys, arrays of surface hot-films, flow visualization, and particle image velocimetry (PIV). The current paper describes the application of active separation control at several locations on the deflected trailing edge flap. High frequency (F(+) approx.= 10) and low frequency amplitude modulation (F(+)AM approx.= 1) of the high frequency excitation were used for control. Preliminary efforts to combine leading and trailing edge flap excitations are also reported.

  3. Active range of motion outcomes after reconstruction of burned wrist and hand deformities.

    PubMed

    Afifi, Ahmed M; Mahboub, Tarek A; Ibrahim Fouad, Amr; Azari, Kodi; Khalil, Haitham H; McCarthy, James E

    2016-06-01

    This works aim is to evaluate the efficacy of skin grafts and flaps in reconstruction of post-burn hand and wrist deformities. A prospective study of 57 burn contractures of the wrist and dorsum of the hand was performed. Flaps were used only if there was a non-vascularized structure after contracture release, otherwise a skin graft was used. Active range of motion (ROM) was used to assess hand function. The extension deformity cohort uniformly underwent skin graft following contracture release with a mean improvement of 71 degrees (p<0.0001). The flexion deformity cohort was treated with either skin grafts (8 patients) or flaps (9 patients) with a mean improvement of 44 degrees (p<0.0001). Skin grafts suffice for dorsal hand contractures to restore functional wrist ROM. For flexion contractures, flaps were more likely for contractures >6 months. Early release of burn contracture is advisable to avoid deep structure contracture.

  4. Efficient passive pitching motion caused by elastic deformation in flexible flapping wing MAVs

    NASA Astrophysics Data System (ADS)

    Nguyen, Trong; Truong, Tien; Yeo, Khoon Seng; Lim, Tee Tai

    2015-11-01

    Computational and experimental models which mimic Hawkmoth wings were constructed to investigate the effects of wing flexibility. The wing actuation mechanism is minimal with only one degree of freedom in sweeping motion with neither active pitching nor elevation. Despite the simplicity of the imparted motion, the wing models in both computations and experiments delivered convincing deformation features such as wing twisting and camber which closely resembles the ones observed in real Hawkmoth wings. The generated aerodynamic forces are remarkable both in magnitude and efficiency. The study hence reveals that a complicated actuation mechanism might not be required to produce the sophisticated and efficient motion of insect wings, which in fact could be the result of collective elastic deformation thanks to their highly optimized structure mainly comprised of well-organized veins and membranes.

  5. Boron-nitride and aluminum-nitride "Pringles" and flapping motion.

    PubMed

    Fa, Wei; Chen, Shuang; Zeng, Xiao Cheng

    2014-07-18

    Motivated by the recent successful synthesis of a new nanocarbon, namely, a warped, double-concave graphene "Pringle" (Nat. Chem., 2013, 5, 739), we investigate properties of warped boron-nitride (BN) and aluminum-nitride (AlN) analogues, i.e., the non-planar B40N40H30 and Al40N40H30 "Pringles" using density functional theory (DFT) calculations. Particular attention is placed on the effect of non-hexagonal rings on the stability and physical properties of BN and AlN Pringles. We find that the warped BN and AlN Pringles with one pentagon and five heptagons are stable without imaginary frequencies. Both the warped B40N40H30 and Al40N40H30 Pringles are expected to be flexible in solution as both can periodically change their shape in a dynamic "flapping" fashion due to their much lower activation barrier of racemization compared to that of the C80H30 counterpart. Since the warped B40N40H30 possesses a smaller HOMO-LUMO gap than the planar B39N39H30, it is expected that incorporating non-hexagonal ring defects by design can be an effective way to modify electronic properties of BN-based nanoplates.

  6. Human exonuclease 1 (EXO1) activity characterization and its function on flap structures

    PubMed Central

    Keijzers, Guido; Bohr, Vilhelm A.; Rasmussen, Lene Juel

    2015-01-01

    Human exonuclease 1 (EXO1) is involved in multiple DNA metabolism processes, including DNA repair and replication. Most of the fundamental roles of EXO1 have been described in yeast. Here, we report a biochemical characterization of human full-length EXO1. Prior to assay EXO1 on different DNA flap structures, we determined factors essential for the thermodynamic stability of EXO1. We show that enzymatic activity and stability of EXO1 on DNA is modulated by temperature. By characterization of EXO1 flap activity using various DNA flap substrates, we show that EXO1 has a strong capacity for degrading double stranded DNA and has a modest endonuclease or 5′ flap activity. Furthermore, we report novel mechanistic insights into the processing of flap structures, showing that EXO1 preferentially cleaves one nucleotide inwards in a double stranded region of a forked and nicked DNA flap substrates, suggesting a possible role of EXO1 in strand displacement. PMID:26182368

  7. Active Management of Flap-Edge Trailing Vortices

    NASA Technical Reports Server (NTRS)

    Greenblatt, David; Yao, Chung-Sheng; Vey, Stefan; Paschereit, Oliver C.; Meyer, Robert

    2008-01-01

    The vortex hazard produced by large airliners and increasingly larger airliners entering service, combined with projected rapid increases in the demand for air transportation, is expected to act as a major impediment to increased air traffic capacity. Significant reduction in the vortex hazard is possible, however, by employing active vortex alleviation techniques that reduce the wake severity by dynamically modifying its vortex characteristics, providing that the techniques do not degrade performance or compromise safety and ride quality. With this as background, a series of experiments were performed, initially at NASA Langley Research Center and subsequently at the Berlin University of Technology in collaboration with the German Aerospace Center. The investigations demonstrated the basic mechanism for managing trailing vortices using retrofitted devices that are decoupled from conventional control surfaces. The basic premise for managing vortices advanced here is rooted in the erstwhile forgotten hypothesis of Albert Betz, as extended and verified ingeniously by Coleman duPont Donaldson and his collaborators. Using these devices, vortices may be perturbed at arbitrarily long wavelengths down to wavelengths less than a typical airliner wingspan and the oscillatory loads on the wings, and hence the vehicle, are small. Significant flexibility in the specific device has been demonstrated using local passive and active separation control as well as local circulation control via Gurney flaps. The method is now in a position to be tested in a wind tunnel with a longer test section on a scaled airliner configuration. Alternatively, the method can be tested directly in a towing tank, on a model aircraft, a light aircraft or a full-scale airliner. The authors believed that this method will have significant appeal from an industry perspective due to its retrofit potential with little to no impact on cruise (devices tucked away in the cove or retracted); low operating power

  8. Dipolarization, current sheet flapping motion and periodic particle flux enhancements observed during the Galaxy 15 spacecraft anomaly

    NASA Astrophysics Data System (ADS)

    Loto'aniu, Paul; Rodriguez, Juan; Redmon, Robert

    2016-04-01

    On 5 April 2010, the Galaxy 15 spacecraft, orbiting at geosynchronous altitudes experienced an anomaly near local midnight when it stopped responding to any ground commands. Galaxy 15 spacecraft encountered severe plasma conditions while it was in eclipse and during the subsequent anomaly interval and these conditions included a massive magnetic field dipolarization that injected energetic particles from the magnetotail during a substorm. This anomaly was interesting for many reasons including that multiple spacecraft (GOES and THEMIS probes) were well located in the nightside to observe the substorm. At the time of the field line stretching and dipolarization some of the satellites observed magnetic variations together with particle flux enhancements with periodicities of a few minutes. In this study, we detail characteristics of this dipolarization, which was one of the strongest ever observed by a GOES spacecraft, as well as discuss perturbations in the magnetic field and particle fluxes that are indicative of magnetotail current sheet flapping motion.

  9. Wing motion transformation to evaluate aerodynamic coupling in flapping wing flight.

    PubMed

    Faruque, Imraan A; Humbert, J Sean

    2014-12-21

    Whether the remarkable flight performance of insects is because the animals leverage inherent physics at this scale or because they employ specialized neural feedback mechanisms is an active research question. In this study, an empirically derived aerodynamics model is used with a transformation involving a delay and a rotation to identify a class of kinematics that provide favorable roll-yaw coupling. The transformation is also used to transform both synthetic and experimentally measured wing motions onto the manifold representing proverse yaw and to quantify the degree to which freely flying insects make use of passive aerodynamic mechanisms to provide proverse roll-yaw turn coordination. The transformation indicates that recorded insect kinematics do act to provide proverse yaw for a variety of maneuvers. This finding suggests that passive aerodynamic mechanisms can act to reduce the neural feedback demands of an insect׳s flight control strategy.

  10. Wing motion transformation to evaluate aerodynamic coupling in flapping wing flight.

    PubMed

    Faruque, Imraan A; Humbert, J Sean

    2014-12-21

    Whether the remarkable flight performance of insects is because the animals leverage inherent physics at this scale or because they employ specialized neural feedback mechanisms is an active research question. In this study, an empirically derived aerodynamics model is used with a transformation involving a delay and a rotation to identify a class of kinematics that provide favorable roll-yaw coupling. The transformation is also used to transform both synthetic and experimentally measured wing motions onto the manifold representing proverse yaw and to quantify the degree to which freely flying insects make use of passive aerodynamic mechanisms to provide proverse roll-yaw turn coordination. The transformation indicates that recorded insect kinematics do act to provide proverse yaw for a variety of maneuvers. This finding suggests that passive aerodynamic mechanisms can act to reduce the neural feedback demands of an insect׳s flight control strategy. PMID:25128237

  11. Structural integrity design for an active helicopter rotor blade with piezoelectric flap actuators

    NASA Astrophysics Data System (ADS)

    Lee, Jaehwan; Shin, SangJoon

    2011-04-01

    Helicopter uses a rotor system to generate lift, thrust and forces, and its aerodynamic environment is generally complex. Unsteady aerodynamic environment arises such as blade vortex interaction. This unsteady aerodynamic environment induces vibratory aerodynamic loads and high aeroacoustic noise. The aerodynamic load and aeroacoustic noise is at N times the rotor blade revolutions (N/rev). But conventional rotor control system composed of pitch links and swash plate is not capable of adjusting such vibratory loads because its control is restricted to 1/rev. Many active control methodologies have been examined to alleviate the problem. The blade using active control device manipulates the blade pitch angle with N/rev. In this paper, Active Trailing-edge Flap blade, which is one of the active control methods, is designed to reduce the unsteady aerodynamic loads. Active Trailing-edge Flap blade uses a trailing edge flap manipulated by an actuator to change camber line of the airfoil. Piezoelectric actuators are installed inside the blade to manipulate the trailing edge flap.

  12. Pivoting output unit control systems activated by jacks. [for controlling aircraft flaps

    NASA Technical Reports Server (NTRS)

    Belliere, P.

    1978-01-01

    An invention to be used for controlling aircraft flaps is described. It is applicable to control systems with two coaxial output units which pivot simultaneously with respect to two fixed units and which are activated by two opposed, straight coaxial jacks.

  13. Theory of the synchronous motion of an array of floating flap gates oscillating wave surge converter

    NASA Astrophysics Data System (ADS)

    Michele, Simone; Sammarco, Paolo; d'Errico, Michele

    2016-08-01

    We consider a finite array of floating flap gates oscillating wave surge converter (OWSC) in water of constant depth. The diffraction and radiation potentials are solved in terms of elliptical coordinates and Mathieu functions. Generated power and capture width ratio of a single gate excited by incoming waves are given in terms of the radiated wave amplitude in the far field. Similar to the case of axially symmetric absorbers, the maximum power extracted is shown to be directly proportional to the incident wave characteristics: energy flux, angle of incidence and wavelength. Accordingly, the capture width ratio is directly proportional to the wavelength, thus giving a design estimate of the maximum efficiency of the system. We then compare the array and the single gate in terms of energy production. For regular waves, we show that excitation of the out-of-phase natural modes of the array increases the power output, while in the case of random seas we show that the array and the single gate achieve the same efficiency.

  14. The reduction of rotorcraft power and vibration using optimally controlled active gurney flap

    NASA Astrophysics Data System (ADS)

    Bae, Eui Sung

    The main topic of the present study is the application of active control scheme for the reduction of rotorcraft main rotor power reduction and vibratory load. When the helicopter is operated near its flight boundary, the required power and vibratory loads rapidly increases which impose a limit on the helicopter operation. Various methods were proposed and studied in order to achieve performance improvement under such operating condition. The effect of active control scheme was examined for its impact on the performance improvement and vibration reduction in the present study. Numerical simulations are based on the UH-60A Blackhawk helicopter with an active Gurney flap spanning from 70%R to 80%R of the main rotor. For obtaining the aeroelastic response of the rotor blade, finite element method was used to represent elastic blade. The aerodynamic loads acting on the blade are provided by CFD based 2D lookup table. Prescribed wake model was used to resolve the induced inflow over the rotor disk. The unsteady aerodynamic behavior due to the higher harmonic actuation of active Gurney flap was resolved by the time-domain unsteady aerodynamic model. The first part of preliminary study covers parametric study using Gurney flap. Starting with simple rigid blade representation of the rotor blade, the effect of 1/rev Gurney flap actuation was examined on three different gross weights. The effect of active Gurney flap width, the chordwise location of active Gurney flap, the effect of unsteady aerodynamic model, and the effect of 2/rev actuation frequency were examined. The second part of preliminary study was conducted with the elastic blade model to include the effect of torsion dynamics. Performance improvement using active Gurney flap was examined for maximizing thrust capability at two flight speeds. 1/rev Gurney flap actuation increased the gross weight capability up to 1,000 lbs. Also, 1/rev actuation of Gurney flap increased maximum altitude limit of baseline rotor by 1

  15. Reciprocating motion of active deformable particles

    NASA Astrophysics Data System (ADS)

    Tarama, M.; Ohta, T.

    2016-05-01

    Reciprocating motion of an active deformable particle in a homogeneous medium is studied theoretically. For generality, we employ a simple model derived from symmetry considerations for the center-of-mass velocity and elliptical and triangular deformations in two dimensions. We carry out, for the first time, a systematic investigation of the reciprocating motion of a self-propelled particle. It is clarified that spontaneous breaking of the front-rear asymmetry is essential for the reciprocating motion. Moreover, two routes are found for the formation of the reciprocating motion. One is a bifurcation from a motionless stationary state. The other is destabilisation of an oscillatory rectilinear motion.

  16. Application of Sequential Quadratic Programming to Minimize Smart Active Flap Rotor Hub Loads

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi; Leyland, Jane

    2014-01-01

    In an analytical study, SMART active flap rotor hub loads have been minimized using nonlinear programming constrained optimization methodology. The recently developed NLPQLP system (Schittkowski, 2010) that employs Sequential Quadratic Programming (SQP) as its core algorithm was embedded into a driver code (NLP10x10) specifically designed to minimize active flap rotor hub loads (Leyland, 2014). Three types of practical constraints on the flap deflections have been considered. To validate the current application, two other optimization methods have been used: i) the standard, linear unconstrained method, and ii) the nonlinear Generalized Reduced Gradient (GRG) method with constraints. The new software code NLP10x10 has been systematically checked out. It has been verified that NLP10x10 is functioning as desired. The following are briefly covered in this paper: relevant optimization theory; implementation of the capability of minimizing a metric of all, or a subset, of the hub loads as well as the capability of using all, or a subset, of the flap harmonics; and finally, solutions for the SMART rotor. The eventual goal is to implement NLP10x10 in a real-time wind tunnel environment.

  17. Self-propulsion of flapping bodies in viscous fluids: Recent advances and perspectives

    NASA Astrophysics Data System (ADS)

    Wang, Shizhao; He, Guowei; Zhang, Xing

    2016-08-01

    Flapping-powered propulsion is used by many animals to locomote through air or water. Here we review recent experimental and numerical studies on self-propelled mechanical systems powered by a flapping motion. These studies improve our understanding of the mutual interaction between actively flapping bodies and surrounding fluids. The results obtained in these works provide not only new insights into biolocomotion but also useful information for the biomimetic design of artificial flyers and swimmers.

  18. Design of flapping wings for application to single active degree of freedom micro air vehicles

    NASA Astrophysics Data System (ADS)

    Chang, Kelvin Thomas

    This dissertation covers an experimental program to understand how wing compliance influences the performance of flapping micro air vehicle wings. The focus is the design of a membraned flapping wing for a single active degree of freedom mechanism, looking to maximize thrust performance in hover conditions. The optimization approach is unique in that experiments were the chosen engine as opposed to a computation model; this is because of the complexity involved in hover-mode flapping aerodynamics. The flapping mechanism and manufacturing process for fabricating the wings were carefully developed. The uncertainty in the thrust measurement was identified and reduced by implementing precision machining and repeatable techniques for fabrication. This resulted in a reduction of the manufacturing coefficient of variation from 16.8% to 2.6%. Optimization was then conducted for a single objective (Maximize thrust), using a three parameter design space, finding the highest thrust performance in wings with high aspect ratio; then, a multi-objective optimization was conducted with two objectives (Thrust and Power) and a four parameter space. The research then shifted focus to identifying the stiffness and deformation characteristics of high performance wing designs. Static stiffness measurements with a simple line load suggested that high chordwise stiffness or lower spanwise stiffness would be favorable for aerodynamic performance. To explore more components of the deformation, a full-field imaging technique was used and a uniform load was substituted to engage with the membrane. It was found that there is a range of torsional compliance where the wing is most efficient especially at higher flapping frequencies. The final component of the study was the dynamic deformation measurement. The two system, four camera digital image correlation setup uses stroboscopic measurement to capture the wing deformation. The phase shift between the twist and stroke, and the tip deflection

  19. Dynamics of an Active-Site Flap Contributes to Catalysis in a JAMM Family Metallo Deubiquitinase.

    PubMed

    Bueno, Amy N; Shrestha, Rashmi K; Ronau, Judith A; Babar, Aditya; Sheedlo, Michael J; Fuchs, Julian E; Paul, Lake N; Das, Chittaranjan

    2015-10-01

    The endosome-associated deubiquitinase (DUB) AMSH is a member of the JAMM family of zinc-dependent metallo isopeptidases with high selectivity for Lys63-linked polyubiquitin chains, which play a key role in endosomal-lysosomal sorting of activated cell surface receptors. The catalytic domain of the enzyme features a flexible flap near the active site that opens and closes during its catalytic cycle. Structural analysis of its homologues, AMSH-LP (AMSH-like protein) and the fission yeast counterpart, Sst2, suggests that a conserved Phe residue in the flap may be critical for substrate binding and/or catalysis. To gain insight into the contribution of this flap in substrate recognition and catalysis, we generated mutants of Sst2 and characterized them using a combination of enzyme kinetics, X-ray crystallography, molecular dynamics simulations, and isothermal titration calorimetry (ITC). Our analysis shows that the Phe residue in the flap contributes key interactions during the rate-limiting step but not to substrate binding, since mutants of Phe403 exhibit a defect only in kcat but not in KM. Moreover, ITC studies show Phe403 mutants have similar KD for ubiquitin compared to the wild-type enzyme. The X-ray structures of both Phe403Ala and the Phe403Trp, in both the free and ubiquitin bound form, reveal no appreciable structural change that might impair substrate or alter product binding. We observed that the side chain of the Trp residue is oriented identically with respect to the isopeptide moiety of the substrate as the Phe residue in the wild-type enzyme, so the loss of activity seen in this mutant cannot be explained by the absence of a group with the ability to provide van der Waals interactions that facilitate the hyrdolysis of the Lys63-linked diubiquitin. Molecular dynamics simulations indicate that the flap in the Trp mutant is quite flexible, allowing almost free rotation of the indole side chain. Therefore, it is possible that these different dynamic

  20. Reduced In-Plane, Low Frequency Helicopter Noise of an Active Flap Rotor

    NASA Technical Reports Server (NTRS)

    Sim, Ben W.; Janakiram, Ram D.; Barbely, Natasha L.; Solis, Eduardo

    2009-01-01

    Results from a recent joint DARPA/Boeing/NASA/Army wind tunnel test demonstrated the ability to reduce in-plane, low frequency noise of the full-scale Boeing-SMART rotor using active flaps. Test data reported in this paper illustrated that acoustic energy in the first six blade-passing harmonics could be reduced by up to 6 decibels at a moderate airspeed, level flight condition corresponding to advance ratio of 0.30. Reduced noise levels were attributed to selective active flap schedules that modified in-plane blade airloads on the advancing side of the rotor, in a manner, which generated counteracting acoustic pulses that partially offset the negative pressure peaks associated with in-plane, steady thickness noise. These favorable reduced-noise operating states are a strong function of the active flap actuation amplitude, frequency and phase. The associated noise reductions resulted in reduced aural detection distance by up to 18%, but incurred significant vibratory load penalties due to increased hub shear forces. Small reductions in rotor lift-to-drag ratios, of no more than 3%, were also measured

  1. Active Control of Separation From the Flap of a Supercritical Airfoil

    NASA Technical Reports Server (NTRS)

    Melton, LaTunia Pack; Yao, Chung-Sheng; Seifert, Avi

    2006-01-01

    Zero-mass-flux periodic excitation was applied at several regions on a simplified high-lift system to delay the occurrence of flow separation. The NASA Energy Efficient Transport (EET) supercritical airfoil was equipped with a 15% chord simply hinged leading edge flap and a 25% chord simply hinged trailing edge flap. Detailed flow features were measured in an attempt to identify optimal actuator placement. The measurements included steady and unsteady model and tunnel wall pressures, wake surveys, arrays of surface hot-films, flow visualization, and particle image velocimetry (PIV). The current paper describes the application of active separation control at several locations on the deflected trailing edge flap. High frequency (F(+) approximately equal to 10) and low frequency amplitude modulation (F(+) sub AM approximately equal to 1) of the high frequency excitation were used for control. It was noted that the same performance gains were obtained with amplitude modulation and required only 30% of the momentum input required by pure sine excitation.

  2. Pharmacologic partial salvage of a failing free flap with recombinant tissue plasminogen activator (rt-PA).

    PubMed

    Atiyeh, B S; Fuleihan, N S; Musharafieh, R S

    1999-11-01

    Despite all the technical improvements in microvascular surgery and the experience gained in clinical practice, thrombosis at the site of microanastomosis remains a significant problem and a continuous source of frustration to most microsurgeons. Early recognition of vascular complications and prompt reexploration with vascular revision remain an essential and standard conduct for salvage. However, in situations where conditions for no-reflow have been established due to severe vasospasm or prolonged ischemia time, it becomes obvious that surgical reexploration alone is not enough to salvage a failing flap or a replanted limb. In such situations, the loss of the revascularized tissues seems to be inevitable. The authors describe their experience in partially salvaging a failing free flap with recombinant tissue plasminogen activator (rt-PA), reversing an established state of no-reflow. Pharmacologic manipulation of the complex and variable factors influencing anastomotic patency in microvascular tissue transfer seems to offer a new hope for preventing failures, as well as for salvaging failing flaps. It appears also that free-tissue transfer failure is not an all-or-none phenomenon.

  3. Granulocyte/macrophage colony-stimulating factor stimulates the expression of the 5-lipoxygenase-activating protein (FLAP) in human neutrophils

    PubMed Central

    1994-01-01

    The synthesis of leukotrienes in human blood neutrophils chiefly relies on the activity of two enzymes, phospholipase A2 and 5-lipoxygenase (5- LO). In turn, the activation of the 5-LO requires the participation of a recently characterized membrane-bound protein, the 5-LO-activating protein (FLAP). In this study, we have investigated conditions under which FLAP expression in neutrophils may be modulated. Of several cytokines tested, only granulocyte/macrophage colony-stimulating factor (GM-CSF) (and to a lesser extent tumor necrosis factor alpha) significantly increased expression of FLAP. GM-CSF increased FLAP mRNA steady-state levels in a time- and dose-dependent manner. The stimulatory effect of GM-CSF on FLAP mRNA was inhibited by prior treatment of the cells with the transcription inhibitor, actinomycin D, and pretreatment of the cells with the protein synthesis inhibitor, cycloheximide, failed to prevent the increase in FLAP mRNA induced by GM-CSF. The accumulation of newly synthesized FLAP, as determined by immunoprecipitation after incorporation of 35S-labeled amino acids, was also increased after incubation of neutrophils with GM-CSF. In addition, the total level of FLAP protein was increased in GM-CSF- treated neutrophils, as determined by two-dimensional gel electrophoresis, followed by Western blot. GM-CSF did not alter the stability of the FLAP protein, indicating that the effect of GM-CSF on FLAP accumulation was the consequence of increased de novo synthesis as opposed to decreased degradation of FLAP. Finally, incubation of neutrophils with the synthetic glucocorticoid dexamethasone directly stimulated the upregulation of FLAP mRNA and protein, and enhanced the effect of GM-CSF. Taken together, these data demonstrate that FLAP expression may be upmodulated after appropriate stimulation of neutrophils. The increase in FLAP expression induced by GM-CSF in inflammatory conditions could confer upon neutrophils a prolonged capacity to synthesize

  4. Active interrogation of helicopter main rotor faults using trailing edge flap actuation

    NASA Astrophysics Data System (ADS)

    Stevens, Patricia Lynn

    Over the past decade, the helicopter community has become increasingly interested in health monitoring. The rotor system, however, is not sufficiently covered in the current Health and Usage Monitoring Systems (HUMS). This dissertation describes the development and evaluation of a new approach for detecting helicopter rotor faults in which active trailing edge flaps are used to interrogate the system. This work is based on the presumption that trailing edge flaps would be installed for the primary purpose of vibration and/or noise control; health monitoring is a secondary use. Using this approach, the blade is excited by an interrogation signal, which is a low amplitude oscillation at a few discrete frequencies. The blade response is measured and the health of the system is determined using a frequency domain damage identification algorithm. Damage detection and location are achieved via the residual force vector. The residual force vector, coupled with an understanding of the system physics, also provides nature characterization. Quantification of damage extent is achieved via a frequency domain adaptation of the Asymmetric Minimum Rank Perturbation Theory. The active interrogation system is evaluated using an aeroelastic finite element model of the rotor system in hover, including an advanced unsteady aerodynamic model to predict the trailing edge flap loads. Realistic damage models, including distributed bending stiffness damage, torsional stiffness damage, control system stiffness damage, cracks and ballistic damage, are seeded in the rotor system model. Results demonstrate detection, location and quantification of extent of all of the faults tested. The effects of noise and modeling errors are discussed and mitigation techniques are developed. Additionally, a measurability study is included. Benefits of this work include both improved health monitoring for rotorcraft as well as insights into the application of structural damage detection algorithms to a

  5. Multipurpose active/passive motion compensation system

    SciTech Connect

    Sullivan, R.A.; Clements, R.E.; Davenport, M.R.

    1984-05-01

    A microprocessor-controlled active/passive motion compensation system has been developed for deploying a variety of geotechnical in-situ testing devices with mobile drilling rigs from low-cost service vessels. The light-weight rotary heave compensator incorporates a hydraulic motor as the compensator actuator and a servo-controlled closed loop pump to reduce the air storage and power requirements. Unique features of the system are the use of inertial sensors to measure three components of boat motion, the ability to run the system in active/passive or passive modes, and the ability to automatically lower the drillstring at a constant velocity while maintaining motion compensation. Quantitative measurements made during sea trials offshore California yielded motion compensation accuracy approaching 98 percent which is much better than the compensation achieved with passive systems. Results are presented from offshore in-situ testing with a cone penetrometer, a vane shear device, and a suspension PS logger. The system can also be used for other offshore applications.

  6. Numerical analysis of active chordwise flexibility on the performance of non-symmetrical flapping airfoils

    NASA Astrophysics Data System (ADS)

    Tay, W. B.; Lim, K. B.

    2010-01-01

    This paper investigates the effect of active chordwise flexing on the lift, thrust and propulsive efficiency of three types of airfoils. The factors studied are the flexing center location, standard two-sided flexing as well as a type of single-sided flexing. The airfoils are simulated to flap with four configurations, and the effects of flexing under these configurations are investigated. Results show that flexing is not necessarily beneficial for the performance of the airfoils. However, with the correct parameters, efficiency is as high as 0.76 by placing the flexing centre at the trailing edge. The average thrust coefficient is more than twice as high, from 1.63 to 3.57 with flapping and flexing under the right conditions. Moreover, the single-sided flexing also gives an average lift coefficient as high as 4.61 for the S1020 airfoil. The shape of the airfoil does alter the effect of flexing too. Deviating the flexing phase angle away from 90° does not give a significant improvement to the airfoil’s performance. These results greatly enhance the design of a better performing ornithopter wing.

  7. Complementary non-radioactive assays for investigation of human flap endonuclease 1 activity

    PubMed Central

    Dorjsuren, Dorjbal; Kim, Daemyung; Maloney, David J.; Wilson, David M.; Simeonov, Anton

    2011-01-01

    FEN1, a key participant in DNA replication and repair, is the major human flap endonuclease that recognizes and cleaves flap DNA structures. Deficiencies in FEN1 function or deletion of the fen1 gene have profound biological effects, including the suppression of repair of DNA damage incurred from the action of various genotoxic agents. Given the importance of FEN1 in resolving abnormal DNA structures, inhibitors of the enzyme carry a potential as enhancers of DNA-interactive anticancer drugs. To facilitate the studies of FEN1 activity and the search for novel inhibitors, we developed a pair of complementary-readout homogeneous assays utilizing fluorogenic donor/quencher and AlphaScreen chemiluminescence strategies. A previously reported FEN1 inhibitor 3-hydroxy-5-methyl-1-phenylthieno[2,3-d]pyrimidine-2,4(1H,3H)-dione displayed equal potency in the new assays, in agreement with its published IC50. The assays were optimized to a low 4 µl volume and used to investigate a set of small molecules, leading to the identification of previously-unreported FEN1 inhibitors, among which aurintricarboxylic acid and NSC-13755 (an arylstibonic derivative) displayed submicromolar potency (average IC50 of 0.59 and 0.93 µM, respectively). The availability of these simple complementary assays obviates the need for undesirable radiotracer-based assays and should facilitate efforts to develop novel inhibitors for this key biological target. PMID:21062821

  8. Animal flight dynamics II. Longitudinal stability in flapping flight.

    PubMed

    Taylor, G K; Thomas, A L R

    2002-02-01

    Stability is essential to flying and is usually assumed to be especially problematic in flapping flight. If so, problems of stability may have presented a particular hurdle to the evolution of flapping flight. In spite of this, the stability of flapping flight has never been properly analysed. Here we use quasi-static and blade element approaches to analyse the stability provided by a flapping wing. By using reduced order approximations to the natural modes of motion, we show that wing beat frequencies are generally high enough compared to the natural frequencies of motion for a quasi-static approach to be valid as a first approximation. Contrary to expectations, we find that there is noting inherently destabilizing about flapping: beating the wings faster simply amplifies any existing stability or instability, and flapping can even enhance stability compared to gliding at the same air speed. This suggests that aerodynamic stability may not have been a particular hurdle in the evolution of flapping flight. Hovering animals, like hovering helicopters, are predicted to possess neutral static stability. Flapping animals, like fixed wing aircraft, are predicted to be stable in forward flight if the mean flight force acts above and/or behind the centre of gravity. In this case, the downstroke will always be stabilizing. The stabilizing contribution may be diminished by an active upstroke with a low advance ratio and more horizontal stroke plane; other forms of the upstroke may make a small positive contribution to stability. An active upstroke could, therefore, be used to lower stability and enhance manoeuvrability. Translatory mechanisms of unsteady lift production are predicted to amplify the stability predicted by a quasi-static analysis. Non-translatory mechanisms will make little or no contribution to stability. This may be one reason why flies, and other animals which rely upon non-translatory aerodynamic mechanisms, often appear inherently unstable.

  9. Optimal propulsive flapping in Stokes flows.

    PubMed

    Was, Loïc; Lauga, Eric

    2014-03-01

    Swimming fish and flying insects use the flapping of fins and wings to generate thrust. In contrast, microscopic organisms typically deform their appendages in a wavelike fashion. Since a flapping motion with two degrees of freedom is able, in theory, to produce net forces from a time-periodic actuation at all Reynolds numbers, we compute in this paper the optimal flapping kinematics of a rigid spheroid in a Stokes flow. The hydrodynamics for the force generation and energetics of the flapping motion is solved exactly. We then compute analytically the gradient of a flapping efficiency in the space of all flapping gaits and employ it to derive numerically the optimal flapping kinematics as a function of the shape of the flapper and the amplitude of the motion. The kinematics of optimal flapping are observed to depend weakly on the flapper shape and are very similar to the figure-eight motion observed in the motion of insect wings. Our results suggest that flapping could be a exploited experimentally as a propulsion mechanism valid across the whole range of Reynolds numbers.

  10. Optimal propulsive flapping in Stokes flows.

    PubMed

    Was, Loïc; Lauga, Eric

    2014-03-01

    Swimming fish and flying insects use the flapping of fins and wings to generate thrust. In contrast, microscopic organisms typically deform their appendages in a wavelike fashion. Since a flapping motion with two degrees of freedom is able, in theory, to produce net forces from a time-periodic actuation at all Reynolds numbers, we compute in this paper the optimal flapping kinematics of a rigid spheroid in a Stokes flow. The hydrodynamics for the force generation and energetics of the flapping motion is solved exactly. We then compute analytically the gradient of a flapping efficiency in the space of all flapping gaits and employ it to derive numerically the optimal flapping kinematics as a function of the shape of the flapper and the amplitude of the motion. The kinematics of optimal flapping are observed to depend weakly on the flapper shape and are very similar to the figure-eight motion observed in the motion of insect wings. Our results suggest that flapping could be a exploited experimentally as a propulsion mechanism valid across the whole range of Reynolds numbers. PMID:24343130

  11. An experimental and three-dimensional computational study on the aerodynamic contribution to the passive pitching motion of flapping wings in hovering flies.

    PubMed

    Ishihara, D; Horie, T; Niho, T

    2014-11-07

    The relative importance of the wing's inertial and aerodynamic forces is the key to revealing how the kinematical characteristics of the passive pitching motion of insect flapping wings are generated, which is still unclear irrespective of its importance in the design of insect-like micro air vehicles. Therefore, we investigate three species of flies in order to reveal this, using a novel fluid-structure interaction analysis that consists of a dynamically scaled experiment and a three-dimensional finite element analysis. In the experiment, the dynamic similarity between the lumped torsional flexibility model as a first approximation of the dipteran wing and the actual insect is measured by the Reynolds number Re, the Strouhal number St, the mass ratio M, and the Cauchy number Ch. In the computation, the three-dimension is important in order to simulate the stable leading edge vortex and lift force in the present Re regime over 254. The drawback of the present experiment is the difficulty in satisfying the condition of M due to the limitation of available solid materials. The novelty of the present analysis is to complement this drawback using the computation. We analyze the following two cases: (a) The equilibrium between the wing's elastic and fluid forces is dynamically similar to that of the actual insect, while the wing's inertial force can be ignored. (b) All forces are dynamically similar to those of the actual insect. From the comparison between the results of cases (a) and (b), we evaluate the contributions of the equilibrium between the aerodynamic and the wing's elastic forces and the wing's inertial force to the passive pitching motion as 80-90% and 10-20%, respectively. It follows from these results that the dipteran passive pitching motion will be based on the equilibrium between the wing's elastic and aerodynamic forces, while it will be enhanced by the wing's inertial force.

  12. An experimental and three-dimensional computational study on the aerodynamic contribution to the passive pitching motion of flapping wings in hovering flies.

    PubMed

    Ishihara, D; Horie, T; Niho, T

    2014-01-01

    The relative importance of the wing's inertial and aerodynamic forces is the key to revealing how the kinematical characteristics of the passive pitching motion of insect flapping wings are generated, which is still unclear irrespective of its importance in the design of insect-like micro air vehicles. Therefore, we investigate three species of flies in order to reveal this, using a novel fluid-structure interaction analysis that consists of a dynamically scaled experiment and a three-dimensional finite element analysis. In the experiment, the dynamic similarity between the lumped torsional flexibility model as a first approximation of the dipteran wing and the actual insect is measured by the Reynolds number Re, the Strouhal number St, the mass ratio M, and the Cauchy number Ch. In the computation, the three-dimension is important in order to simulate the stable leading edge vortex and lift force in the present Re regime over 254. The drawback of the present experiment is the difficulty in satisfying the condition of M due to the limitation of available solid materials. The novelty of the present analysis is to complement this drawback using the computation. We analyze the following two cases: (a) The equilibrium between the wing's elastic and fluid forces is dynamically similar to that of the actual insect, while the wing's inertial force can be ignored. (b) All forces are dynamically similar to those of the actual insect. From the comparison between the results of cases (a) and (b), we evaluate the contributions of the equilibrium between the aerodynamic and the wing's elastic forces and the wing's inertial force to the passive pitching motion as 80-90% and 10-20%, respectively. It follows from these results that the dipteran passive pitching motion will be based on the equilibrium between the wing's elastic and aerodynamic forces, while it will be enhanced by the wing's inertial force. PMID:25378268

  13. Foot and ankle reconstruction: an experience on the use of 14 different flaps in 226 cases.

    PubMed

    Zhu, Yue-Liang; Wang, Yi; He, Xiao-Qing; Zhu, Min; Li, Fu-Bin; Xu, Yong-Qing

    2013-11-01

    The aim of this report was to present our experience on the use of different flaps for soft tissue reconstruction of the foot and ankle. From 2007 to 2012, the soft tissue defects of traumatic injuries of the foot and ankle were reconstructed using 14 different flaps in 226 cases (162 male and 64 female). There were 62 pedicled flaps and 164 free flaps used in reconstruction. The pedicled flaps included sural flap, saphenous flap, dorsal pedal neurocutaneous flap, pedicled peroneal artery perforator flap, pedicled tibial artery perforator flap, and medial plantar flap. The free flaps were latissimus musculocutaneous flap, anterolateral thigh musculocutaneous flap, groin flap, lateral arm flap, anterolateral thigh perforator flap, peroneal artery perforator flap, thoracdorsal artery perforator flap, medial arm perforator flap. The sensory nerve coaptation was not performed for all of flaps. One hundred and ninety-four cases were combined with open fractures. One hundred and sixty-two cases had tendon. Among 164 free flaps, 8 flaps were completely lost, in which the defects were managed by the secondary procedures. Among the 57 flaps for plantar foot coverage (25 pedicled flaps and 32 free flaps), ulcers were developed in 5 pedicled flaps and 6 free flaps after weight bearing, and infection was found in 14 flaps. The donor site complications were seen in 3 cases with the free anterolateral thigh perforator flap transfer. All of limbs were preserved and the patients regained walking and daily activities. All of patients except for one regained protective sensation from 3 to 12 months postoperatively. Our experience showed that the sural flap and saphenous flap could be good options for the coverage of the defects at malleolus, dorsal hindfoot and midfoot. Plantar foot, forefoot and large size defects could be reconstructed with free anterolateral thigh perforator flap. For the infected wounds with dead spce, the free latissimus dorsi musculocutaneous flap remained to

  14. Perceived causality influences brain activity evoked by biological motion.

    PubMed

    Morris, James P; Pelphrey, Kevin A; McCarthy, Gregory

    2008-01-01

    Using functional magnetic resonance imaging (fMRI), we investigated brain activity in an observer who watched the hand and arm motions of an individual when that individual was, or was not, the cause of the motion. Subjects viewed a realistic animated 3D character who sat at a table containing four pistons. On Intended Motion trials, the character raised his hand and arm upwards. On Unintended Motion trials, the piston under one of the character's hands pushed the hand and arm upward with the same motion. Finally, during Non-Biological Motion control trials, a piston pushed a coffee mug upward in the same smooth motion. Hand and arm motions, regardless of intention, evoked significantly more activity than control trials in a bilateral region that extended ventrally from the posterior superior temporal sulcus (pSTS) region and which was more spatially extensive in the right hemisphere. The left pSTS near the temporal-parietal junction, robustly differentiated between the Intended Motion and Unintended Motion conditions. Here, strong activity was observed for Intended Motion trials, while Unintended Motion trials evoked similar activity as the coffee mug trials. Our results demonstrate a strong hemispheric bias in the role of the pSTS in the perception of causality of biological motion. PMID:18633843

  15. Active motion assisted by correlated stochastic torques.

    PubMed

    Weber, Christian; Radtke, Paul K; Schimansky-Geier, Lutz; Hänggi, Peter

    2011-07-01

    The stochastic dynamics of an active particle undergoing a constant speed and additionally driven by an overall fluctuating torque is investigated. The random torque forces are expressed by a stochastic differential equation for the angular dynamics of the particle determining the orientation of motion. In addition to a constant torque, the particle is supplemented by random torques, which are modeled as an Ornstein-Uhlenbeck process with given correlation time τ(c). These nonvanishing correlations cause a persistence of the particles' trajectories and a change of the effective spatial diffusion coefficient. We discuss the mean square displacement as a function of the correlation time and the noise intensity and detect a nonmonotonic dependence of the effective diffusion coefficient with respect to both correlation time and noise strength. A maximal diffusion behavior is obtained if the correlated angular noise straightens the curved trajectories, interrupted by small pirouettes, whereby the correlated noise amplifies a straightening of the curved trajectories caused by the constant torque.

  16. Spontaneous motion in hierarchically assembled active matter

    PubMed Central

    Sanchez, Tim; Chen, Daniel T. N.; DeCamp, Stephen J.; Heymann, Michael; Dogic, Zvonimir

    2012-01-01

    With exquisite precision and reproducibility, cells orchestrate the cooperative action of thousands of nanometer-sized molecular motors to carry out mechanical tasks at much larger length scales, such as cell motility, division and replication1. Besides their biological importance, such inherently non-equilibrium processes are an inspiration for developing biomimetic active materials from microscopic components that consume energy to generate continuous motion2–4. Being actively driven, these materials are not constrained by the laws of equilibrium statistical mechanics and can thus exhibit highly sought-after properties such as autonomous motility, internally generated flows and self-organized beating5–7. Starting from extensile microtubule bundles, we hierarchically assemble active analogs of conventional polymer gels, liquid crystals and emulsions. At high enough concentration, microtubules form a percolating active network characterized by internally driven chaotic flows, hydrodynamic instabilities, enhanced transport and fluid mixing. When confined to emulsion droplets, 3D networks spontaneously adsorb onto the droplet surfaces to produce highly active 2D nematic liquid crystals whose streaming flows are controlled by internally generated fractures and self-healing, as well as unbinding and annihilation of oppositely charged disclination defects. The resulting active emulsions exhibit unexpected properties, such as autonomous motility, which are not observed in their passive analogues. Taken together, these observations exemplify how assemblages of animate microscopic objects exhibit collective biomimetic properties that are starkly different from those found in materials assembled from inanimate building blocks, challenging us to develop a theoretical framework that would allow for a systematic engineering of their far-from-equilibrium material properties. PMID:23135402

  17. Tissue expansion using osmotically active hydrogel systems for direct closure of the donor defect of the radial forearm flap.

    PubMed

    Bergé, S J; Wiese, K G; von Lindern, J J; Niederhagen, B; Appel, T; Reich, R H

    2001-07-01

    Although widely used, the radial forearm flap has been criticized for the poor quality of its donor site. Attempts to avoid donor-site problems have concentrated on the elaboration of the split-thickness and full-thickness skin graft methods of reconstruction. Skin grafts frequently fail over the flexor carpi radialis tendon, leading to chronic skin breakdown or, at best, tendon adhesion. Tissue expansion appears to be a good alternative that allows the use of local tissues to ultimately improve the forearm donor-site appearance. To avoid the disadvantages of traditional silicone balloon expanders (such as pressure peaks, infection, the valve at a distance from the expander, postoperative fillings), an osmotically active system was used. In an 18-month prospective study, 10 osmotically active hydrogel tissue expanders were placed on the forearms of 10 patients. The radial forearm flap was performed for intraoral reconstruction after surgical resection of oral cavity malignancies. The study showed that, in nine out of 10 patients, the expanded skin achieved was sufficient to cover the donor site after raising the forearm flap. Additionally, the expansion-related swelling pressure was well tolerated by the patients, the cosmetic results were very satisfactory, and the incidence of complications was very low. By using osmotically active hydrogel tissue expanders, there is no postoperative filling and no risk of complications arising from defective balloon expanders, filling valves, or missing ports.

  18. Using Kinesthetic Activities to Teach Ptolemaic and Copernican Retrograde Motion

    ERIC Educational Resources Information Center

    Richards, Ted

    2012-01-01

    This paper describes a method for teaching planetary retrograde motion, and the Ptolemaic and Copernican accounts of retrograde motion, by means of a series kinesthetic learning activities (KLAs). In the KLAs described, the students literally walk through the motions of the planets in both systems. A retrospective statistical analysis shows that…

  19. Motion-base simulator study of control of an externally blown flap STOL transport aircraft after failure of an outboard engine during landing approach

    NASA Technical Reports Server (NTRS)

    Middleton, D. B.; Hurt, G. J., Jr.; Bergeron, H. P.; Patton, J. M., Jr.; Deal, P. L.; Champine, R. A.

    1975-01-01

    A moving-base simulator investigation of the problems of recovery and landing of a STOL aircraft after failure of an outboard engine during final approach was made. The approaches were made at 75 knots along a 6 deg glide slope. The engine was failed at low altitude and the option to go around was not allowed. The aircraft was simulated with each of three control systems, and it had four high-bypass-ratio fan-jet engines exhausting against large triple-slotted wing flaps to produce additional lift. A virtual-image out-the-window television display of a simulated STOL airport was operating during part of the investigation. Also, a simple heads-up flight director display superimposed on the airport landing scene was used by the pilots to make some of the recoveries following an engine failure. The results of the study indicated that the variation in visual cues and/or motion cues had little effect on the outcome of a recovery, but they did have some effect on the pilot's response and control patterns.

  20. Control of Flap Vortices

    NASA Technical Reports Server (NTRS)

    Greenblatt, David

    2005-01-01

    A wind tunnel investigation was carried out on a semi-span wing model to assess the feasibility of controlling vortices emanating from outboard flaps and tip-flaps by actively varying the degree of boundary layer separation. Separation was varied by means of perturbations produced from segmented zero-efflux oscillatory blowing slots, while estimates of span loadings and vortex sheet strengths were obtained by integrating wing surface pressures. These estimates were used as input to inviscid rollup relations as a means of predicting changes to the vortex characteristics resulting from the perturbations. Surveys of flow in the wake of the outboard and tip-flaps were made using a seven-hole probe, from which the vortex characteristics were directly deduced. Varying the degree of separation had a marked effect on vortex location, strength, tangential velocity, axial velocity and size for both outboard and tip-flaps. Qualitative changes in vortex characteristics were well predicted by the inviscid rollup relations, while the failure to account for viscosity was presumed to be the main reason for observed discrepancies. Introducing perturbations near the outboard flap-edges or on the tip-flap exerted significant control over vortices while producing negligible lift excursions.

  1. 2D CFD Analysis of an Airfoil with Active Continuous Trailing Edge Flap

    NASA Astrophysics Data System (ADS)

    Jaksich, Dylan; Shen, Jinwei

    2014-11-01

    Efficient and quieter helicopter rotors can be achieved through on-blade control devices, such as active Continuous Trailing-Edge Flaps driven by embedded piezoelectric material. This project aims to develop a CFD simulation tool to predict the aerodynamic characteristics of an airfoil with CTEF using open source code: OpenFOAM. Airfoil meshes used by OpenFOAM are obtained with MATLAB scripts. Once created it is possible to rotate the airfoil to various angles of attack. When the airfoil is properly set up various OpenFOAM properties, such as kinematic viscosity and flow velocity, are altered to achieve the desired testing conditions. Upon completion of a simulation, the program gives the lift, drag, and moment coefficients as well as the pressure and velocity around the airfoil. The simulation is then repeated across multiple angles of attack to give full lift and drag curves. The results are then compared to previous test data and other CFD predictions. This research will lead to further work involving quasi-steady 2D simulations incorporating NASTRAN to model aeroelastic deformation and eventually to 3D aeroelastic simulations. NSF ECE Grant #1358991 supported the first author as an REU student.

  2. Brain activity accompanying perception of implied motion in abstract paintings.

    PubMed

    Kim, Chai-Youn; Blake, Randolph

    2007-01-01

    Early 20th century artists including Duchamp and Balla tried to portray moving objects on a static canvas by superimposing objects in successive portrayals of an action. We investigated whether implied motion in those paintings is associated with activation of motion-sensitive area MT+. In Experiment 1, we found that observers rated these kinds of paintings higher in portraying motion than they did other abstract paintings in which motion is not intended. We also found that observers who had previously experienced abstract paintings with implied motion tended to give higher motion ratings to that class of paintings. In Experiment 2, we used functional magnetic resonance imaging (fMRI) to measure brain activity of observers while viewing abstract paintings receiving the highest and the lowest motion rating scores in Experiment 1. We found MT+, but not primary visual cortex (V1), showed greater BOLD responses to abstract paintings with implied motion than to abstract paintings with little motion impression, but only in observers with prior experience viewing those kinds of paintings. These results imply that the neural machinery ordinarily engaged during perception of real visual motion is activated when people view paintings explicitly designed to convey a sense of visual motion. Experience, however, is necessary to achieve this sense of motion.

  3. Vibration reduction in helicopter rotors using an actively controlled partial span trailing edge flap located on the blade

    NASA Technical Reports Server (NTRS)

    Millott, T. A.; Friedmann, P. P.

    1994-01-01

    This report describes an analytical study of vibration reduction in a four-bladed helicopter rotor using an actively controlled, partial span, trailing edge flap located on the blade. The vibration reduction produced by the actively controlled flap (ACF) is compared with that obtained using individual blade control (IBC), in which the entire blade is oscillated in pitch. For both cases a deterministic feedback controller is implemented to reduce the 4/rev hub loads. For all cases considered, the ACF produced vibration reduction comparable with that obtained using IBC, but consumed only 10-30% of the power required to implement IBC. A careful parametric study is conducted to determine the influence of blade torsional stiffness, spanwise location of the control flap, and hinge moment correction on the vibration reduction characteristics of the ACF. The results clearly demonstrate the feasibility of this new approach to vibration reduction. It should be emphasized than the ACF, used together with a conventional swashplate, is completely decoupled from the primary flight control system and thus it has no influence on the airworthiness of the helicopter. This attribute is potentially a significant advantage when compared to IBC.

  4. Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

    NASA Technical Reports Server (NTRS)

    Kottapalli, Sesi B. R.

    2010-01-01

    Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

  5. Simultaneous BVI noise and vibration reduction in rotorcraft using actively-controlled flaps and including performance considerations

    NASA Astrophysics Data System (ADS)

    Patt, Daniel A.

    This work presents the development and application of an active control approach for reduction of both vibration and noise induced by helicopter rotor blade vortex interaction (BVI). Control is implemented through single or dual actively controlled flaps (ACFs) on each blade. Low-speed helicopter flight is prone to severe BVI, resulting in elevated vibration and noise levels. Existing research has suggested that when some form of active control is used to reduce vibration, noise will increase and vice versa. The present research achieves simultaneous reduction of noise and vibration, and also investigates the physical sources of the observed reduction. The initial portion of this work focused on developing a tool for simulating helicopter noise and vibrations in the BVI flight regime. A method for predicting compressible unsteady blade surface pressure distribution on rotor blades was developed and combined with an enhanced free-wake model and an acoustic prediction tool with provisions for blade flexibility. These elements were incorporated within an aeroelastic analysis featuring fully coupled flap-lag-torsional blade dynamics. Subsequently, control algorithms were developed that were effective for reducing noise and vibration even in the nonlinear BVI flight regime; saturation limits were incorporated constraining flap deflections to specified limits. The resulting simulation was also validated with a wide range of experimental data, achieving excellent correlation. Finally, a number of active control studies were performed. Multi-component vibration reductions of 40--80% could be achieved, while incurring a small noise penalty. Noise was reduced using an onboard feedback microphone; reductions of 4--10 dB on the advancing side were observed on a plane beneath the rotor when using dual flaps. Finally, simultaneous noise and vibration reduction was studied. A reduction of about 5 dB in noise on the advancing side combined with a 60% reduction in vibration was

  6. An Electrolyte-Free Conducting Polymer Actuator that Displays Electrothermal Bending and Flapping Wing Motions under a Magnetic Field.

    PubMed

    Uh, Kyungchan; Yoon, Bora; Lee, Chan Woo; Kim, Jong-Man

    2016-01-20

    Electroactive materials that change shape in response to electrical stimulation can serve as actuators. Electroactive actuators of this type have great utility in a variety of technologies, including biomimetic artificial muscles, robotics, and sensors. Electroactive actuators developed to date often suffer from problems associated with the need to use electrolytes, slow response times, high driving voltages, and short cycle lifetimes. Herein, we report an electrolyte-free, single component, polymer electroactive actuator, which has a fast response time, high durability, and requires a low driving voltage (<5 V). The process employed for production of this material involves wet-spinning of a preorganized camphorsulfonic acid (CSA)-doped polyaniline (PANI) gel, which generates long, flexible, and conductive (∼270 S/cm) microfibers. Reversible bending motions take place upon application of an alternating current (AC) to the PANI polymer. This motion, promoted by a significantly low driving voltage (<0.5 V) in the presence of an external magnetic field, has a very large swinging speed (9000 swings/min) that lies in the range of those of flies and bees (1000-15000 swings/min) and is fatigue-resistant (>1000000 cycles). PMID:26717199

  7. Efficient flapping flight of pterosaurs

    NASA Astrophysics Data System (ADS)

    Strang, Karl Axel

    In the late eighteenth century, humans discovered the first pterosaur fossil remains and have been fascinated by their existence ever since. Pterosaurs exploited their membrane wings in a sophisticated manner for flight control and propulsion, and were likely the most efficient and effective flyers ever to inhabit our planet. The flapping gait is a complex combination of motions that sustains and propels an animal in the air. Because pterosaurs were so large with wingspans up to eleven meters, if they could have sustained flapping flight, they would have had to achieve high propulsive efficiencies. Identifying the wing motions that contribute the most to propulsive efficiency is key to understanding pterosaur flight, and therefore to shedding light on flapping flight in general and the design of efficient ornithopters. This study is based on published results for a very well-preserved specimen of Coloborhynchus robustus, for which the joints are well-known and thoroughly described in the literature. Simplifying assumptions are made to estimate the characteristics that can not be inferred directly from the fossil remains. For a given animal, maximizing efficiency is equivalent to minimizing power at a given thrust and speed. We therefore aim at finding the flapping gait, that is the joint motions, that minimize the required flapping power. The power is computed from the aerodynamic forces created during a given wing motion. We develop an unsteady three-dimensional code based on the vortex-lattice method, which correlates well with published results for unsteady motions of rectangular wings. In the aerodynamic model, the rigid pterosaur wing is defined by the position of the bones. In the aeroelastic model, we add the flexibility of the bones and of the wing membrane. The nonlinear structural behavior of the membrane is reduced to a linear modal decomposition, assuming small deflections about the reference wing geometry. The reference wing geometry is computed for

  8. Flap Endonuclease 1

    PubMed Central

    Balakrishnan, Lata; Bambara, Robert A.

    2013-01-01

    First discovered as a structure-specific endonuclease that evolved to cut at the base of single-stranded flaps, flap endonuclease (FEN1) is now recognized as a central component of cellular DNA metabolism. Substrate specificity allows FEN1 to process intermediates of Okazaki fragment maturation, long-patch base excision repair, telomere maintenance, and stalled replication fork rescue. For Okazaki fragments, the RNA primer is displaced into a 5′ flap and then cleaved off. FEN1 binds to the flap base and then threads the 5′ end of the flap through its helical arch and active site to create a configuration for cleavage. The threading requirement prevents this active nuclease from cutting the single-stranded template between Okazaki fragments. FEN1 efficiency and specificity are critical to the maintenance of genome fidelity. Overall, recent advances in our knowledge of FEN1 suggest that it was an ancient protein that has been fine-tuned over eons to coordinate many essential DNA transactions. PMID:23451868

  9. Stress optimization of leaf-spring crossed flexure pivots for an active Gurney flap mechanism

    NASA Astrophysics Data System (ADS)

    Freire Gómez, Jon; Booker, Julian D.; Mellor, Phil H.

    2015-04-01

    The EU's Green Rotorcraft programme is pursuing the development of a functional and airworthy Active Gurney Flap (AGF) for a full-scale helicopter rotor blade. Interest in the development of this `smart adaptive rotor blade' technology lies in its potential to provide a number of aerodynamic benefits, which would in turn translate into a reduction in fuel consumption and noise levels. The AGF mechanism selected employs leaf-spring crossed flexure pivots. These provide important advantages over bearings as they are not susceptible to seizing and do not require maintenance (i.e. lubrication or cleaning). A baseline design of this mechanism was successfully tested both in a fatigue rig and in a 2D wind tunnel environment at flight-representative deployment schedules. For full validation, a flight test would also be required. However, the severity of the in-flight loading conditions would likely compromise the mechanical integrity of the pivots' leaf-springs in their current form. This paper investigates the scope for stress reduction through three-dimensional shape optimization of the leaf-springs of a generic crossed flexure pivot. To this end, a procedure combining a linear strain energy formulation, a parametric leaf-spring profile definition and a series of optimization algorithms is employed. The resulting optimized leaf-springs are proven to be not only independent of the angular rotation at which the pivot operates, but also linearly scalable to leaf-springs of any length, minimum thickness and width. Validated using non-linear finite element analysis, the results show very significant stress reductions relative to pivots with constant cross section leaf-springs, of up to as much as 30% for the specific pivot configuration employed in the AGF mechanism. It is concluded that shape optimization offers great potential for reducing stress in crossed flexure pivots and, consequently, for extending their fatigue life and/or rotational range.

  10. Benchmarking aerodynamic prediction of unsteady rotor aerodynamics of active flaps on wind turbine blades using ranging fidelity tools

    NASA Astrophysics Data System (ADS)

    Barlas, Thanasis; Jost, Eva; Pirrung, Georg; Tsiantas, Theofanis; Riziotis, Vasilis; Navalkar, Sachin T.; Lutz, Thorsten; van Wingerden, Jan-Willem

    2016-09-01

    Simulations of a stiff rotor configuration of the DTU 10MW Reference Wind Turbine are performed in order to assess the impact of prescribed flap motion on the aerodynamic loads on a blade sectional and rotor integral level. Results of the engineering models used by DTU (HAWC2), TUDelft (Bladed) and NTUA (hGAST) are compared to the CFD predictions of USTUTT-IAG (FLOWer). Results show fairly good comparison in terms of axial loading, while alignment of tangential and drag-related forces across the numerical codes needs to be improved, together with unsteady corrections associated with rotor wake dynamics. The use of a new wake model in HAWC2 shows considerable accuracy improvements.

  11. Using Kinesthetic Activities to Teach Ptolemaic and Copernican Retrograde Motion

    NASA Astrophysics Data System (ADS)

    Richards, Ted

    2012-06-01

    This paper describes a method for teaching planetary retrograde motion, and the Ptolemaic and Copernican accounts of retrograde motion, by means of a series kinesthetic learning activities (KLAs). In the KLAs described, the students literally walk through the motions of the planets in both systems. A retrospective statistical analysis shows that students who participated in these activities performed better on examination questions pertaining to retrograde motion than students who did not. Potential explanations for this result, including the breaking of classroom routine, the effect of body movement on conceptual memory, and egocentric spatial proprioception, are considered.

  12. Conical Euler simulation and active suppression of delta wing rocking motion

    NASA Technical Reports Server (NTRS)

    Lee, Elizabeth M.; Batina, John T.

    1990-01-01

    A conical Euler code was developed to study unsteady vortex-dominated flows about rolling highly-swept delta wings, undergoing either forced or free-to-roll motions including active roll suppression. The flow solver of the code involves a multistage Runge-Kutta time-stepping scheme which uses a finite volume spatial discretization of the Euler equations on an unstructured grid of triangles. The code allows for the additional analysis of the free-to-roll case, by including the rigid-body equation of motion for its simultaneous time integration with the governing flow equations. Results are presented for a 75 deg swept sharp leading edge delta wing at a freestream Mach number of 1.2 and at alpha equal to 10 and 30 deg angle of attack. A forced harmonic analysis indicates that the rolling moment coefficient provides: (1) a positive damping at the lower angle of attack equal to 10 deg, which is verified in a free-to-roll calculation; (2) a negative damping at the higher angle of attack equal to 30 deg at the small roll amplitudes. A free-to-roll calculation for the latter case produces an initially divergent response, but as the amplitude of motion grows with time, the response transitions to a wing-rock type of limit cycle oscillation. The wing rocking motion may be actively suppressed, however, through the use of a rate-feedback control law and antisymmetrically deflected leading edge flaps. The descriptions of the conical Euler flow solver and the free-to-roll analysis are presented. Results are also presented which give insight into the flow physics associated with unsteady vortical flows about forced and free-to-roll delta wings, including the active roll suppression of this wing-rock phenomenon.

  13. People can understand descriptions of motion without activating visual motion brain regions

    PubMed Central

    Dravida, Swethasri; Saxe, Rebecca; Bedny, Marina

    2013-01-01

    What is the relationship between our perceptual and linguistic neural representations of the same event? We approached this question by asking whether visual perception of motion and understanding linguistic depictions of motion rely on the same neural architecture. The same group of participants took part in two language tasks and one visual task. In task 1, participants made semantic similarity judgments with high motion (e.g., “to bounce”) and low motion (e.g., “to look”) words. In task 2, participants made plausibility judgments for passages describing movement (“A centaur hurled a spear … ”) or cognitive events (“A gentleman loved cheese …”). Task 3 was a visual motion localizer in which participants viewed animations of point-light walkers, randomly moving dots, and stationary dots changing in luminance. Based on the visual motion localizer we identified classic visual motion areas of the temporal (MT/MST and STS) and parietal cortex (inferior and superior parietal lobules). We find that these visual cortical areas are largely distinct from neural responses to linguistic depictions of motion. Motion words did not activate any part of the visual motion system. Motion passages produced a small response in the right superior parietal lobule, but none of the temporal motion regions. These results suggest that (1) as compared to words, rich language stimuli such as passages are more likely to evoke mental imagery and more likely to affect perceptual circuits and (2) effects of language on the visual system are more likely in secondary perceptual areas as compared to early sensory areas. We conclude that language and visual perception constitute distinct but interacting systems. PMID:24009592

  14. A Miniature Controllable Flapping Wing Robot

    NASA Astrophysics Data System (ADS)

    Arabagi, Veaceslav Gheorghe

    The agility and miniature size of nature's flapping wing fliers has long baffled researchers, inspiring biological studies, aerodynamic simulations, and attempts to engineer their robotic replicas. Flapping wing flight is characterized by complex reciprocating wing kinematics, transient aerodynamic effects, and very small body lengths. These characteristics render robotic flapping wing aerial vehicles ideal for surveillance and defense applications, search and rescue missions, and environment monitoring, where their ability to hover and high maneuverability is immensely beneficial. One of the many difficulties in creating flapping wing based miniature robotic aerial vehicles lies in generating a proper wing trajectory that would result in sufficient lift forces for hovering and maneuvering. Since design of a flapping wing system is a balance between overall weight and the number of actuated inputs, we take the approach of having minimal controlled inputs, allowing passive behavior wherever possible. Hence, we propose a completely passive wing pitch reversal design that relies on wing inertial dynamics, an elastic energy storage mechanism, and low Reynolds number aerodynamic effects. Theoretical models, compiling previous research on piezoelectric actuators, four-bar transmissions, and aerodynamics effects, are developed and used as basis for a complete numerical simulation. Limitations of the model are discussed in comparison to experimental results obtained from a working prototype of the proposed passive pitch reversal flapping wing mechanism. Given that the mechanism is under-actuated, methods to control lift force generation by actively varying system parameters are proposed, discussed, and tested experimentally. A dual wing aerial platform is developed based on the passive pitch reversal wing concept. Design considerations are presented, favoring controllability and structural rigidity of the final platform. Finite element analysis and experimental

  15. Uses of motion imagery in activity-based intelligence

    NASA Astrophysics Data System (ADS)

    Lash, Thomas D.

    2013-05-01

    Activity-Based Intelligence (ABI) was defined by the Office of the Undersecretary of Defense for Intelligence as "a discipline of intelligence where the analysis and subsequent collection is focused on activity and transactions associated with an entity, population, or area of interest." ABI is inherently multi-INT, and motion imagery is a rich data source for ABI analysis. Motion imagery provides a unique temporal aspect which is critical for activity detection and classification. Additionally, motion imagery tends to have high spatial oversampling useful for determining activities and patterns above the noise threshold.

  16. Contractile activity of the pectoralis in the zebra finch according to mode and velocity of flap-bounding flight.

    PubMed

    Tobalske, Bret W; Puccinelli, Lisa A; Sheridan, David C

    2005-08-01

    We studied flying zebra finch (Taeniopygia guttata, N = 12), to provide a new test of a long-standing ;fixed-gear' hypothesis that flap-bounding birds use only intermittent non-flapping phases, instead of variation in muscle activity, to vary mechanical power output in flight. Using sonomicrometry and electromyography, we measured in vivo fascicle length and neuromuscular recruitment in the pectoralis as the birds flew in different flight modes (level, ascending, descending; mean velocity 1.6+/-0.3 m s(-1)) and across velocities in a new, variable-speed wind tunnel (0-12 m s(-1)). Synchronized high-speed digital video (250 Hz) provided a record of wing kinematics. Flight mode had a significant effect upon pectoralis strain, strain rate, fractional shortening and the relative timing of muscle activity (onset, offset and duration). Among flight velocities, we observed significant variation in pectoralis strain, fractional lengthening and shortening, strain rate, relative electromyographic (EMG) amplitude, and EMG duration and offset. In particular, variation in strain rate and relative EMG amplitude indicates that the fixed-gear hypothesis should be rejected. Instead, it appears that zebra finch vary work and power output within wingbeats by modulating muscle contractile behavior and between wingbeats using intermittent bounds. Muscle activity patterns and wing kinematics were similar between free flight and wind tunnel flight at similar speeds. Comparing flights with and without surgically implanted transducers and electrodes, zebra finch exhibited a reduction in maximum velocity (from 14 to 12 m s(-1)) and a significant increase in wingbeat frequency and percent time flapping. This identifies a potential limitation of in vivo flight measurements, and similar studies of bird flight should, therefore, include measurements of the extent to which flight performance is compromised by experimental protocol.

  17. Schooling of flapping wings: Simulations

    NASA Astrophysics Data System (ADS)

    Masoud, Hassan; Becker, Alexander; Ristroph, Leif; Shelley, Michael

    2014-11-01

    We examine the locomotion of an infinite array of wings that heave vertically with a prescribed sinusoidal motion and are free to translate in the horizontal direction. To do this, we simulate the motion of a freely translating flapping airfoil in a domain with periodic horizontal boundary conditions. These simulations indicate that the wings can ``take advantage'' of their collectively generated wake flows. In agreement with our experiments in a rotational geometry, we find ranges of flapping frequency over which there are multiple stable states of locomotion, with one of these swimming states having both higher speeds and efficiencies than an isolated flapping and locomoting wing. A simple mathematical model, which emphasizes the importance of history dependence in vortical flows, explains this multi-stability. These results may be important to understanding the role of hydrodynamic interactions in fish schooling and bird flocking.

  18. HIGH EFFICIENCY STRUCTURAL FLOWTHROUGH ROTOR WITH ACTIVE FLAP CONTROL: VOLUME ZERO: OVERVIEW AND COMMERCIAL PATH

    SciTech Connect

    Zuteck, Michael D.; Jackson, Kevin L.; Santos, Richard A.

    2015-05-16

    The Zimitar one-piece rotor primary structure is integrated, so balanced thrust and gravity loads flow through the hub region without transferring out of its composite material. Large inner rotor geometry is used since there is no need to neck down to a blade root region and pitch bearing. Rotor control is provided by a highly redundant, five flap system on each blade, sized so that easily handled standard electric linear actuators are sufficient.

  19. HIGH EFFICIENCY STRUCTURAL FLOWTHROUGH ROTOR WITH ACTIVE FLAP CONTROL: VOLUME TWO: INNOVATION & COST OF ENERGY

    SciTech Connect

    Zuteck, Michael D.; Jackson, Kevin L.; Santos, Richard A.

    2015-05-16

    The Zimitar one-piece rotor primary structure is integrated, so balanced thrust and gravity loads flow through the hub region without transferring out of its composite material. Large inner rotor geometry is used since there is no need to neck down to a blade root region and pitch bearing. Rotor control is provided by a highly redundant, five flap system on each blade, sized so that easily handled standard electric linear actuators are sufficient.

  20. HIGH EFFICIENCY STRUCTURAL FLOWTHROUGH ROTOR WITH ACTIVE FLAP CONTROL: VOLUME THREE: MARKET & TEAM

    SciTech Connect

    Zuteck, Michael D.; Jackson, Kevin L.; Santos, Richard A.

    2015-05-16

    The Zimitar one-piece rotor primary structure is integrated, so balanced thrust and gravity loads flow through the hub region without transferring out of its composite material. Large inner rotor geometry is used since there is no need to neck down to a blade root region and pitch bearing. Rotor control is provided by a highly redundant, five flap system on each blade, sized so that easily handled standard electric linear actuators are sufficient.

  1. HIGH EFFICIENCY STRUCTURAL FLOWTHROUGH ROTOR WITH ACTIVE FLAP CONTROL: VOLUME ONE: PRELIMINARY DESIGN REPORT

    SciTech Connect

    Zuteck, Michael D.; Jackson, Kevin L.; Santos, Richard A.; Chow, Ray; Nordenholz, Thomas R.; Wamble, John Lee

    2015-05-16

    The Zimitar one-piece rotor primary structure is integrated, so balanced thrust and gravity loads flow through the hub region without transferring out of its composite material. Large inner rotor geometry is used since there is no need to neck down to a blade root region and pitch bearing. Rotor control is provided by a highly redundant, five flap system on each blade, sized so that easily handled standard electric linear actuators are sufficient.

  2. Ontogeny of aerial righting and wing flapping in juvenile birds.

    PubMed

    Evangelista, Dennis; Cam, Sharlene; Huynh, Tony; Krivitskiy, Igor; Dudley, Robert

    2014-08-01

    Mechanisms of aerial righting in juvenile chukar partridge (Alectoris chukar) were studied from hatching to 14 days-post-hatching (dph). Asymmetric movements of the wings were used from 1 to 8 dph to effect progressively more successful righting behaviour via body roll. Following 8 dph, wing motions transitioned to bilaterally symmetric flapping that yielded aerial righting via nose-down pitch, along with substantial increases in vertical force production during descent. Ontogenetically, the use of such wing motions to effect aerial righting precedes both symmetric flapping and a previously documented behaviour in chukar (i.e. wing-assisted incline running) hypothesized to be relevant to incipient flight evolution in birds. These findings highlight the importance of asymmetric wing activation and controlled aerial manoeuvres during bird development and are potentially relevant to understanding the origins of avian flight. PMID:25165451

  3. Abdominal muscle activation changes if the purpose is to control pelvis motion or thorax motion.

    PubMed

    Vera-Garcia, Francisco J; Moreside, Janice M; McGill, Stuart M

    2011-12-01

    The aim of this study was to compare trunk muscular recruitment and lumbar spine kinematics when motion was constrained to either the thorax or the pelvis. Nine healthy women performed four upright standing planar movements (rotations, anterior-posterior translations, medial-lateral translations, and horizontal circles) while constraining pelvis motion and moving the thorax or moving the pelvis while minimizing thorax motion, and four isometric trunk exercises (conventional curl-up, reverse curl-up, cross curl-up, and reverse cross curl-up). Surface EMG (upper and lower rectus abdominis, lateral and medial aspects of external oblique, internal oblique, and latissimus dorsi) and 3D lumbar displacements were recorded. Pelvis movements produced higher EMG amplitudes of the oblique abdominals than thorax motions in most trials, and larger lumbar displacements in the medial-lateral translations and horizontal circles. Conversely, thorax movements produced larger rotational lumbar displacement than pelvis motions during rotations and higher EMG amplitudes for latissimus dorsi during rotations and anterior-posterior translations and for lower rectus abdominis during the crossed curl-ups. Thus, different neuromuscular compartments appear when the objective changes from pelvis to thorax motion. This would suggest that both movement patterns should be considered when planning spine stabilization programs, to optimize exercises for the movement and muscle activations desired.

  4. 4,5-Diarylisoxazol-3-carboxylic acids: A new class of leukotriene biosynthesis inhibitors potentially targeting 5-lipoxygenase-activating protein (FLAP).

    PubMed

    Banoglu, Erden; Çelikoğlu, Erşan; Völker, Susanna; Olgaç, Abdurrahman; Gerstmeier, Jana; Garscha, Ulrike; Çalışkan, Burcu; Schubert, Ulrich S; Carotti, Andrea; Macchiarulo, Antonio; Werz, Oliver

    2016-05-01

    In this article, we report novel leukotriene (LT) biosynthesis inhibitors that may target 5-lipoxygenase-activating protein (FLAP) based on the previously identified isoxazole derivative (8). The design and synthesis was directed towards a subset of 4,5-diaryl-isoxazole-3-carboxylic acid derivatives as LT biosynthesis inhibitors. Biological evaluation disclosed a new skeleton of potential anti-inflammatory agents, exemplified by 39 and 40, which potently inhibit cellular 5-LO product synthesis (IC50 = 0.24 μM, each) seemingly by targeting FLAP with weak inhibition on 5-LO (IC50 ≥ 8 μM). Docking studies and molecular dynamic simulations with 5-LO and FLAP provide valuable insights into potential binding modes of the inhibitors. Together, these diaryl-isoxazol-3-carboxylic acids may possess potential as leads for development of effective anti-inflammatory drugs through inhibition of LT biosynthesis. PMID:26922224

  5. Wavelet-based motion artifact removal for electrodermal activity.

    PubMed

    Chen, Weixuan; Jaques, Natasha; Taylor, Sara; Sano, Akane; Fedor, Szymon; Picard, Rosalind W

    2015-01-01

    Electrodermal activity (EDA) recording is a powerful, widely used tool for monitoring psychological or physiological arousal. However, analysis of EDA is hampered by its sensitivity to motion artifacts. We propose a method for removing motion artifacts from EDA, measured as skin conductance (SC), using a stationary wavelet transform (SWT). We modeled the wavelet coefficients as a Gaussian mixture distribution corresponding to the underlying skin conductance level (SCL) and skin conductance responses (SCRs). The goodness-of-fit of the model was validated on ambulatory SC data. We evaluated the proposed method in comparison with three previous approaches. Our method achieved a greater reduction of artifacts while retaining motion-artifact-free data.

  6. Reduction of Urease Activity by Interaction with the Flap Covering the Active Site

    PubMed Central

    Macomber, Lee; Minkara, Mona S.; Hausinger, Robert P.; Merz, Kenneth M.

    2015-01-01

    With the increasing appreciation for the human microbiome coupled with the global rise of antibiotic resistant organisms, it is imperative that new methods be developed to specifically target pathogens. To that end, a novel computational approach was devised to identify compounds that reduce the activity of urease, a medically important enzyme of Helicobacter pylori, Proteus mirabilis, and many other microorganisms. Urease contains a flexible loop that covers its active site; Glide was used to identify small molecules predicted to lock this loop in an open conformation. These compounds were screened against the model urease from Klebsiella aerogenes and the natural products epigallocatechin and quercetin were shown to inhibit at low and high micromolar concentrations, respectively. These molecules exhibit a strong time-dependent inactivation of urease that was not due to their oxygen sensitivity. Rather, these compounds appear to inactivate urease by reacting with a specific Cys residue located on the flexible loop. Substitution of this cysteine by alanine in the C319A variant increased the urease resistance to both epigallocatechin and quercetin, as predicted by the computational studies. Protein dynamics are integral to the function of many enzymes; thus, identification of compounds that lock an enzyme into a single conformation presents a useful approach to define potential inhibitors. PMID:25594724

  7. Video summarization using descriptors of motion activity: a motion activity based approach to key-frame extraction from video shots

    NASA Astrophysics Data System (ADS)

    Divakaran, Ajay; Radhakrishnan, Regunathan; Peker, Kadir A.

    2001-10-01

    We describe a video summarization technique that uses motion descriptors computed in the compressed domain. It can either speed up conventional color-based video summarization techniques, or rapidly generate a key-frame based summary by itself. The basic hypothesis of the work is that the intensity of motion activity of a video segment is a direct indication of its `summarizability,' which we experimentally verify using the MPEG-7 motion activity descriptor and the fidelity measure proposed in H. S. Chang, S. Sull, and S. U. Lee, `Efficient video indexing scheme for content-based retrieval,' IEEE Trans. Circuits Syst. Video Technol. 9(8), (1999). Note that the compressed domain extraction of motion activity intensity is much simpler than the color-based calculations. We are thus able to quickly identify easy to summarize segments of a video sequence since they have a low intensity of motion activity. We are able to easily summarize these segments by simply choosing their first frames. We can then apply conventional color-based summarization techniques to the remaining segments. We thus speed up color-based summarization by reducing the number of segments processed. Our results also motivate a simple and novel key-frame extraction technique that relies on a motion activity based nonuniform sampling of the frames. Our results indicate that it can either be used by itself or to speed up color-based techniques as explained earlier.

  8. Piezoelectrically actuated insect scale flapping wing

    NASA Astrophysics Data System (ADS)

    Mukherjee, Sujoy; Ganguli, Ranjan

    2010-04-01

    An energy method is used in order to derive the non-linear equations of motion of a smart flapping wing. Flapping wing is actuated from the root by a PZT unimorph in the piezofan configuration. Dynamic characteristics of the wing, having the same size as dragonfly Aeshna Multicolor, are analyzed using numerical simulations. It is shown that flapping angle variations of the smart flapping wing are similar to the actual dragonfly wing for a specific feasible voltage. An unsteady aerodynamic model based on modified strip theory is used to obtain the aerodynamic forces. It is found that the smart wing generates sufficient lift to support its own weight and carry a small payload. It is therefore a potential candidate for flapping wing of micro air vehicles.

  9. Active motion, communicative aggregations, and the spatial closure of Umwelt.

    PubMed

    Kull, K

    2000-01-01

    On the basis of a simple model of movable organisms that are supplied by semiotic force of attraction or repulsion, several general features of spatial behavior are demonstrated: (1) the stochastic spatial distribution of actively moving organisms is unstable; (2) simple or complex aggregations of organisms appear as a result of active motion; and (3) the ability for active motion ties the organisms with place. These results show that models that apply an internalist approach can considerably simplify the theory of spatial behavior of organic systems. Explanations based on the effects of Darwinian fitness may not be necessary for understanding the origin of biological aggregations.

  10. An Active Flow Circulation Controlled Flap Concept for General Aviation Aircraft Applications

    NASA Technical Reports Server (NTRS)

    Jones, Gregory S.; Viken, Sally A.; Washburn, Anthony E.; Jenkins, Luther N.; Cagle, C. Mark

    2002-01-01

    A recent focus on revolutionary aerodynamic concepts has highlighted the technology needs of general aviation and personal aircraft. New and stringent restrictions on these types of aircraft have placed high demands on aerodynamic performance, noise, and environmental issues. Improved high lift performance of these aircraft can lead to slower takeoff and landing speeds that can be related to reduced noise and crash survivability issues. Circulation Control technologies have been around for 65 years, yet have been avoided due to trade offs of mass flow, pitching moment, perceived noise etc. The need to improve the circulation control technology for general aviation and personal air-vehicle applications is the focus of this paper. This report will describe the development of a 2-D General Aviation Circulation Control (GACC) wing concept that utilizes a pulsed pneumatic flap.

  11. The plane problem of the flapping wing

    NASA Technical Reports Server (NTRS)

    Birnbaum, Walter

    1954-01-01

    In connection with an earlier report on the lifting vortex sheet which forms the basis of the following investigations this will show how the methods developed there are also suitable for dealing with the air forces for a wing with a circulation variable with time. The theory of a propulsive wing flapping up and down periodically in the manner of a bird's wing is developed. This study shows how the lift and its moment result as a function of the flapping motion, what thrust is attainable, and how high is the degree of efficiency of this flapping propulsion unit if the air friction is disregarded.

  12. Repositioning free laser in situ keratomileusis flaps.

    PubMed

    Todani, Amit; Al-Arfaj, Khalid; Melki, Samir A

    2010-02-01

    We describe a protocol for adequate repositioning of free laser in situ keratomileusis (LASIK) corneal flaps created by a Moria M2 microkeratome even in the absence of fiduciary marks. In an enucleated porcine globe, a free flap was created by initially placing a longitudinal incision at the proposed hinge site followed by activating the forward pass of the automated microkeratome. A protocol was devised based on placement of a positioning dot on the free flap before the flap is retrieved from the microkeratome head. Preplaced surgical landmarks were used as a guide to determine the correct alignment of the free flap. Adequate orientation of the free flap to the stromal bed was achieved in 9 porcine eyes using the positioning dot method. The technique is applicable to the Moria M2 microkeratome only and must be validated for other types of keratomes.

  13. A bio-inspired study on tidal energy extraction with flexible flapping wings.

    PubMed

    Liu, Wendi; Xiao, Qing; Cheng, Fai

    2013-09-01

    Previous research on the flexible structure of flapping wings has shown an improved propulsion performance in comparison to rigid wings. However, not much is known about this function in terms of power efficiency modification for flapping wing energy devices. In order to study the role of the flexible wing deformation in the hydrodynamics of flapping wing energy devices, we computationally model the two-dimensional flexible single and twin flapping wings in operation under the energy extraction conditions with a large Reynolds number of 106. The flexible motion for the present study is predetermined based on a priori structural result which is different from a passive flexibility solution. Four different models are investigated with additional potential local distortions near the leading and trailing edges. Our simulation results show that the flexible structure of a wing is beneficial to enhance power efficiency by increasing the peaks of lift force over a flapping cycle, and tuning the phase shift between force and velocity to a favourable trend. Moreover, the impact of wing flexibility on efficiency is more profound at a low nominal effective angle of attack (AoA). At a typical flapping frequency f * = 0.15 and nominal effective AoA of 10°, a flexible integrated wing generates 7.68% higher efficiency than a rigid wing. An even higher increase, around six times that of a rigid wing, is achievable if the nominal effective AoA is reduced to zero degrees at feathering condition. This is very attractive for a semi-actuated flapping energy system, where energy input is needed to activate the pitching motion. The results from our dual-wing study found that a parallel twin-wing device can produce more power compared to a single wing due to the strong flow interaction between the two wings.

  14. Investigation of Energy Harvesting Using Flapping Foils

    NASA Astrophysics Data System (ADS)

    Mivehchi, Amin; Persichetti, Amanda; Dunham, Brandon; Dahl, Jason M.

    2013-11-01

    When harvesting kinetic energy using a flapping foil, the separation of coherent structures in the wake is crucial for determining forces on the body. Applications for utilizing energy harvesting with a flapping foil include powering of local, low power equipment and recharging AUV batteries that use flapping foils for propulsion and maneuvering. In each of these cases, it is critical to accurately predict the physical behavior and location of vortices in relation to the motion of the body in order to maximize energy output. A two-dimensional open source boundary data immersion method (LilyPad) is used for simulating the flapping motion of a foil for energy harvesting in a current. Forced motion of the flapping body indicates theoretical efficiencies for energy harvesting near 43 percent under specific flapping conditions. A simple control scheme based on pressure sensing on the surface of the foil is developed to control pitch of the foil while energy harvesting occurs in the heave direction. The control scheme is tested through real time numerical simulation. Comparisons are made with physical laboratory experiments, demonstrating high efficiencies in energy harvesting.

  15. Contribution of complex stapes motion to cochlea activation.

    PubMed

    Eiber, Albrecht; Huber, Alexander M; Lauxmann, Michael; Chatzimichalis, Michail; Sequeira, Damien; Sim, Jae Hoon

    2012-02-01

    Classic theories of hearing have considered only a translational component (piston-like component) of the stapes motion as being the effective stimulus for cochlear activation and thus the sensation of hearing. Our previous study (Huber et al., 2008) qualitatively showed that rotational components around the long and short axes of the footplate (rocking-like components) lead to cochlear activation as well. In this study, the contribution of the piston-like and rocking-like components of the stapes motion to cochlea activation was quantitatively investigated with measurements in live guinea pigs and a related mathematical description. The isolated stapes in anesthetized guinea pigs was stimulated by a three-axis piezoelectric actuator, and 3-D motions of the stapes and compound action potential (CAP) of the cochlea were measured simultaneously. The measured values were used to fit a hypothesis of the CAP as a linear combination of the logarithms of the piston-like and rocking-like components. Both the piston-like and rocking-like components activate cochlear responses when they exceed certain thresholds. These thresholds as well as the relation between CAP and intensity of the motion component were different for piston-like and rocking-like components. The threshold was found to be higher and the sensitivity lower for the rocking-like component than the corresponding values for the piston-like component. The influence of the rocking-like component was secondary in cases of piston-dominant motions of the stapes although it may become significant for low amplitudes of the piston-like component.

  16. Internal motions prime cIAP1 for rapid activation.

    PubMed

    Phillips, Aaron H; Schoeffler, Allyn J; Matsui, Tsutomu; Weiss, Thomas M; Blankenship, John W; Zobel, Kerry; Giannetti, Anthony M; Dueber, Erin C; Fairbrother, Wayne J

    2014-12-01

    Cellular inhibitor of apoptosis 1 (cIAP1) is a ubiquitin ligase with critical roles in the control of programmed cell death and NF-κB signaling. Under normal conditions, the protein exists as an autoinhibited monomer, but proapoptotic signals lead to its dimerization, activation and proteasomal degradation. This view of cIAP1 as a binary switch has been informed by static structural studies that cannot access the protein's dynamics. Here, we use NMR spectroscopy to study micro- and millisecond motions of specific domain interfaces in human cIAP1 and use time-resolved small-angle X-ray scattering to observe the global conformational changes necessary for activation. Although motions within each interface of the 'closed' monomer are insufficient to activate cIAP1, they enable associations with catalytic partners and activation factors. We propose that these internal motions facilitate rapid peptide-induced opening and dimerization of cIAP1, which undergoes a dramatic spring-loaded structural transition. PMID:25383668

  17. Active motion induced break-up of colloidal gels

    NASA Astrophysics Data System (ADS)

    Szakasits, Megan; Solomon, Michael

    2015-03-01

    We found that fractal gel networks of polystyrene colloids can be broken up by active motion of Janus colloids that have been incorporated into them. Janus particles were synthesized by electron beam deposition of platinum onto one micron carboxylate modified polystyrene particles. Through addition of the divalent salt magnesium chloride, an initially stable suspension of Janus and polystyrene colloids, present in equal proportion, underwent aggregation to yield a fractal gel. The Janus colloids were activated by addition of 30% v/v hydrogen peroxide through a porous hydrogel membrane. Changes in structure and dynamics were visualized by two channel confocal laser scanning microscopy (CLSM). By means of image analysis, we calculated the mean squared displacement (MSD) and radial distribution function (RDF) for gel samples before and after addition of hydrogen peroxide. The MSD confirmed the Janus particles we synthesized undergo active motion. The RDF and cluster size distribution of gel samples before and after addition of peroxide demonstrate how active motion broke apart the gel network into smaller clusters.

  18. Motion.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    2002-01-01

    This issue of Exploratorium Magazine focuses on the topic of motion. Contents include: (1) "First Word" (Zach Tobias); (2) "Cosmic Collisions" (Robert Irion); (3) "The Mobile Cell" (Karen E. Kalumuck); (4) "The Paths of Paths" (Steven Vogel); (5) "Fragments" (Pearl Tesler); (6) "Moving Pictures" (Amy Snyder); (7) "Plants on the Go" (Katharine…

  19. Hybrid magnetic mechanism for active locomotion based on inchworm motion

    NASA Astrophysics Data System (ADS)

    Kim, Sung Hoon; Hashi, Shuichiro; Ishiyama, Kazushi

    2013-02-01

    Magnetic robots have been studied in the past. Insect-type micro-robots are used in various biomedical applications; researchers have developed inchworm micro-robots for endoscopic use. A biological inchworm has a looping locomotion gait. However, most inchworm micro-robots depend on a general bending, or bellows, motion. In this paper, we introduce a new robotic mechanism using magnetic force and torque control in a rotating magnetic field for a looping gait. The proposed robot is controlled by the magnetic torque, attractive force, and body mechanisms (two stoppers, flexible body, and different frictional legs). The magnetic torque generates a general bending motion. In addition, the attractive force and body mechanisms produce the robot’s looping motion within a rotating magnetic field and without the use of an algorithm for field control. We verified the device’s performance and analyzed the motion through simulations and various experiments. The robot mechanism can be applied to active locomotion for various medical robots, such as wireless endoscopes.

  20. Motion Sensor Reactivity in Physically Active Young Adults

    ERIC Educational Resources Information Center

    Behrens, Timothy K.; Dinger, Mary K.

    2007-01-01

    The purpose of this study was to examine whether young adults changed their physical activity (PA) behavior when wearing motion sensors. PA patterns of 119 young adults (M age = 20.82 years, SD = 1.50, M body mass index = 23.93 kg/m[superscript 2] , SD = 4.05) were assessed during 2 consecutive weeks. In Week 1, participants wore an accelerometer.…

  1. Thermally activated depinning motion of contact lines in pseudopartial wetting.

    PubMed

    Du, Lingguo; Bodiguel, Hugues; Colin, Annie

    2014-07-01

    We investigate pressure-driven motion of liquid-liquid menisci in circular tubes, for systems in pseudopartial wetting conditions. The originality of this type of wetting lies in the coexistence of a macroscopic contact angle with a wetting liquid film covering the solid surface. Focusing on small capillary numbers, we report observations of an apparent contact angle hysteresis at first sight similar to the standard partial wetting case. However, this apparent hysteresis exhibits original features. We observe very long transient regimes before steady state, up to several hundreds of seconds. Furthermore, in steady state, the velocities are nonzero, meaning that the contact line is not strongly pinned to the surface defects, but are very small. The velocity of the contact line tends to vanish near the equilibrium contact angle. These observations are consistent with the thermally activated depinning theory that has been proposed to describe partial wetting systems on disordered substrates and suggest that a single physical mechanism controls both the hysteresis (or the pinning) and the motion of the contact line. The proposed analysis leads to the conclusion that the depinning activated energy is lower with pseudopartial wetting systems than with partial wetting ones, allowing the direct observation of the thermally activated motion of the contact line. PMID:25122310

  2. Motion Sensor Use for Physical Activity Data: Methodological Considerations

    PubMed Central

    McCarthy, Margaret; Grey, Margaret

    2015-01-01

    Background Physical inactivity continues to be a major risk factor for cardiovascular disease, and only one half of adults in the United States meet physical activity (PA) goals. PA data are often collected for surveillance or for measuring change after an intervention. One of the challenges in PA research is quantifying exactly how much and what type of PA is taking place—especially because self-report instruments have inconsistent validity. Objective The purpose is to review the elements to consider when collecting PA data via motion sensors, including the difference between PA and exercise; type of data to collect; choosing the device; length of time to monitor PA; instructions to the participants; and interpretation of the data. Methods The current literature on motion sensor research was reviewed and synthesized to summarize relevant considerations when using a motion sensor to collect PA data. Results Exercise is a division of PA that is structured, planned, and repetitive. Pedometer data includes steps taken, and calculated distance and energy expenditure. Accelerometer data includes activity counts and intensity. The device chosen depends on desired data, cost, validity, and ease of use. Reactivity to the device may influence the duration of data collection. Instructions to participants may vary depending on purpose of the study. Experts suggest pedometer data be reported as steps—since that is the direct output—and distance traveled and energy expenditure are estimated values. Accelerometer count data may be analyzed to provide information on time spent in moderate or vigorous activity. Discussion Thoughtful decision making about PA data collection using motion sensor devices is needed to advance nursing science. PMID:26126065

  3. Flow field of flexible flapping wings

    NASA Astrophysics Data System (ADS)

    Sallstrom, Erik

    The agility and maneuverability of natural fliers would be desirable to incorporate into engineered micro air vehicles (MAVs). However, there is still much for engineers to learn about flapping flight in order to understand how such vehicles can be built for efficient flying. The goal of this study is to develop a methodology for capturing high quality flow field data around flexible flapping wings in a hover environment and to interpret it to gain a better understanding of how aerodynamic forces are generated. The flow field data was captured using particle image velocimetry (PIV) and required that measurements be taken around a repeatable flapping motion to obtain phase-averaged data that could be studied throughout the flapping cycle. Therefore, the study includes the development of flapping devices with a simple repeatable single degree of freedom flapping motion. The acquired flow field data has been examined qualitatively and quantitatively to investigate the mechanisms behind force production in hovering flight and to relate it to observations in previous research. Specifically, the flow fields have been investigated around a rigid wing and several carbon fiber reinforced flexible membrane wings. Throughout the whole study the wings were actuated with either a sinusoidal or a semi-linear flapping motion. The semi-linear flapping motion holds the commanded angular velocity nearly constant through half of each half-stroke while the sinusoidal motion is always either accelerating or decelerating. The flow fields were investigated by examining vorticity and vortex structures, using the Q criterion as the definition for the latter, in two and three dimensions. The measurements were combined with wing deflection measurements to demonstrate some of the key links in how the fluid-structure interactions generated aerodynamic forces. The flow fields were also used to calculate the forces generated by the flapping wings using momentum balance methods which yielded

  4. Autonomous Motion Learning for Intra-Vehicular Activity Space Robot

    NASA Astrophysics Data System (ADS)

    Watanabe, Yutaka; Yairi, Takehisa; Machida, Kazuo

    Space robots will be needed in the future space missions. So far, many types of space robots have been developed, but in particular, Intra-Vehicular Activity (IVA) space robots that support human activities should be developed to reduce human-risks in space. In this paper, we study the motion learning method of an IVA space robot with the multi-link mechanism. The advantage point is that this space robot moves using reaction force of the multi-link mechanism and contact forces from the wall as space walking of an astronaut, not to use a propulsion. The control approach is determined based on a reinforcement learning with the actor-critic algorithm. We demonstrate to clear effectiveness of this approach using a 5-link space robot model by simulation. First, we simulate that a space robot learn the motion control including contact phase in two dimensional case. Next, we simulate that a space robot learn the motion control changing base attitude in three dimensional case.

  5. The racquet conjunctival flap.

    PubMed

    Cies, W A; Odeh-Nasrala, N

    1976-01-01

    In situations requiring a conjunctival flap to cover a corneal defect, the racquet flap technique is a simple relatively noninvasive method. Less conjunctiva is sacrificed and yet the flap is fully maintained by the one pedicle. The bulbar conjunctiva is maintained in an essentially normal state.

  6. Motion of Euglena gracilis: Active fluctuations and velocity distribution

    NASA Astrophysics Data System (ADS)

    Romanczuk, P.; Romensky, M.; Scholz, D.; Lobaskin, V.; Schimansky-Geier, L.

    2015-07-01

    We study the velocity distribution of unicellular swimming algae Euglena gracilis using optical microscopy and active Brownian particle theory. To characterize a peculiar feature of the experimentally observed distribution at small velocities we use the concept of active fluctuations, which was recently proposed for the description of stochastically self-propelled particles [Romanczuk, P. and Schimansky-Geier, L., Phys. Rev. Lett. 106, 230601 (2011)]. In this concept, the fluctuating forces arise due to internal random performance of the propulsive motor. The fluctuating forces are directed in parallel to the heading direction, in which the propulsion acts. In the theory, we introduce the active motion via the depot model [Schweitzer, et al., Phys. Rev. Lett. 80(23), 5044 (1998)]. We demonstrate that the theoretical predictions based on the depot model with active fluctuations are consistent with the experimentally observed velocity distributions. In addition to the model with additive active noise, we obtain theoretical results for a constant propulsion with multiplicative noise.

  7. Acute Deep Hand Burns Covered by a Pocket Flap-Graft

    PubMed Central

    Pradier, Jean-Philippe; Oberlin, Christophe; Bey, Eric

    2007-01-01

    Objective: We evaluated the long-term outcome of the “pocket flap-graft” technique, used to cover acute deep burns of the dorsum of the hand, and analyzed surgical alternatives. Methods: This was a 6-year, retrospective study of 8 patients with extensive burns and 1 patient with a single burn (11 hands in all) treated by defatted abdominal wall pockets. We studied the medical records of the patients, and conducted a follow-up examination. Results: All hands had fourth-degree thermal burns caused by flames, with exposure of tendons, bones, and joints, and poor functional prognosis. One third of patients had multiple injuries. Burns affected an average of 36% of the hand surface, and mean coverage was 92.8 cm2. One patient died. The 8 others were seen at 30-month follow-up: the skin quality of the flap was found to be good in 55% of the cases, the score on the Vancouver Scar Scale was 2.4, the Kapandji score was 4.5, and total active motion was 37% of that of a normal hand. Hand function was limited in only 2 cases, 8 patients were able to drive, and 3 patients had gone back to work. Conclusion: The pocket flap-graft allows preservation of hand function following severe burns, when local or free flaps are impossible to perform. Debulking of the flap at the time of elevation limits the need for secondary procedures. PMID:17268577

  8. Photothermally activated motion and ignition using aluminum nanoparticles

    SciTech Connect

    Abboud, Jacques E.; Chong Xinyuan; Zhang Mingjun; Zhang Zhili; Jiang Naibo; Roy, Sukesh; Gord, James R.

    2013-01-14

    The aluminum nanoparticles (Al NPs) are demonstrated to serve as active photothermal media, to enhance and control local photothermal energy deposition via the photothermal effect activated by localized surface plasmon resonance (LSPR) and amplified by Al NPs oxidation. The activation source is a 2-AA-battery-powered xenon flash lamp. The extent of the photothermally activated movement of Al NPs can be {approx}6 mm. Ignition delay can be {approx}0.1 ms. Both scanning electron microscopy and energy-dispersive X-ray spectroscopy measurements of motion-only and after-ignition products confirm significant Al oxidation occurs through sintering and bursting after the flash exposure. Simulations suggest local heat generation is enhanced by LSPR. The positive-feedback effects from the local heat generation amplified by Al oxidation produce a large increase in local temperature and pressure, which enhances movement and accelerates ignition.

  9. Motion transition of active filaments: rotation without hydrodynamic interactions.

    PubMed

    Jiang, Huijun; Hou, Zhonghuai

    2014-02-21

    We investigate the dynamics of an active semiflexible filament in a bead–rod model involving dynamically the hydrodynamic interaction (HI), active force, filament flexibility and viscous drag. We find that the filament can show three distinct types of motion, namely, translation, snaking and rotation, with the variation of the rigidity or active force. The transition from translation to snaking is continuous and mainly due to transverse instability, while the snaking–rotation transition is first-order like and shown to result from a type of symmetry breaking associated with the shape kinematics. Of particular interest, we find that HI is not necessary for the rotation or snaking motion, but can enlarge remarkably the parameter regions in which they can occur. Combining with local collisions, we show that, for the parameter region where HI is essential for the maintenance of rotation curvature of a single filament, HI is also essential for the emergence of collective vortexes. Thus, our findings provide new insights into the subtle role of HI in the formation of collective structures in active systems PMID:24983114

  10. Fusion of smartphone motion sensors for physical activity recognition.

    PubMed

    Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J M

    2014-06-10

    For physical activity recognition, smartphone sensors, such as an accelerometer and a gyroscope, are being utilized in many research studies. So far, particularly, the accelerometer has been extensively studied. In a few recent studies, a combination of a gyroscope, a magnetometer (in a supporting role) and an accelerometer (in a lead role) has been used with the aim to improve the recognition performance. How and when are various motion sensors, which are available on a smartphone, best used for better recognition performance, either individually or in combination? This is yet to be explored. In order to investigate this question, in this paper, we explore how these various motion sensors behave in different situations in the activity recognition process. For this purpose, we designed a data collection experiment where ten participants performed seven different activities carrying smart phones at different positions. Based on the analysis of this data set, we show that these sensors, except the magnetometer, are each capable of taking the lead roles individually, depending on the type of activity being recognized, the body position, the used data features and the classification method employed (personalized or generalized). We also show that their combination only improves the overall recognition performance when their individual performances are not very high, so that there is room for performance improvement. We have made our data set and our data collection application publicly available, thereby making our experiments reproducible.

  11. Crew activity and motion effects on the space station

    NASA Technical Reports Server (NTRS)

    Rochon, Brian V.; Scheer, Steven A.

    1987-01-01

    Among the significant sources of internal disturbances that must be considered in the design of space station vibration control systems are the loads induced on the structure from various crew activities. Flight experiment T013, flown on the second manned mission of Skylab, measured force and moment time histories for a range of preplanned crew motions and activities. This experiment has proved itself invaluable as a source of on-orbit crew induced loads that has allowed a space station forcing function data base to be built. This will enable forced response such as acceleration and deflections, attributable to crew activity, to be calculated. The flight experiment, resultant database and structural model pre-processor, analysis examples and areas of combined research shall be described.

  12. Active Motion Control of Tetrahymena pyriformis by Galvanotaxis and Geotaxis

    NASA Astrophysics Data System (ADS)

    Kim, Jihoon; Byun, Doyoung; Kim, Min Jun

    2013-11-01

    Recently, there has been increasing interest in the swimming behavior of microorganisms and biologically inspired micro-robots. These microorganisms naturally accompanied by complex motions. Therefore it is important to understand the flow characteristics as well as control mechanisms. One of eukaryotic cells, the protozoa are a diverse group of unicellular organisms, many of which are motile cilia. Motile cilia are cover on the surface of cell in large numbers and beat in oriented waves. Sequential beating motions of a single cilium form metachronal strokes, producing a propagation wave, and therefore the body is achieved propulsion force. So preliminary studies are achieved to understand the flow induced by swimming microorganisms. Based on hydrodynamic results, the follow study of a few micro-scale protozoa cell, such as the Tetrahymena pyriformis, has provided active or passive control into several external stimuli. In typical control methods, the galvanotaxis and geotaxis were adopted active and passive control, respectively. The validation of galvanotaxis is used DC and AC voltage. In terms of geotaxis, corrugated microstructures were used to control in the microchannel. This research was supported by the Ministry of Education, Science and Technology (MEST, 2011-0016461), National Science Foundation (NSF) CMMI Control Systems Program (#1000255) and Army Research Office (W911NF-11-1-0490).

  13. Coupling of active motion and advection shapes intracellular cargo transport.

    PubMed

    Khuc Trong, Philipp; Guck, Jochen; Goldstein, Raymond E

    2012-07-13

    Intracellular cargo transport can arise from passive diffusion, active motor-driven transport along cytoskeletal filament networks, and passive advection by fluid flows entrained by such cargo-motor motion. Active and advective transport are thus intrinsically coupled as related, yet different representations of the same underlying network structure. A reaction-advection-diffusion system is used here to show that this coupling affects the transport and localization of a passive tracer in a confined geometry. For sufficiently low diffusion, cargo localization to a target zone is optimized either by low reaction kinetics and decoupling of bound and unbound states, or by a mostly disordered cytoskeletal network with only weak directional bias. These generic results may help to rationalize subtle features of cytoskeletal networks, for example as observed for microtubules in fly oocytes.

  14. Documenting Western Burrowing Owl Reproduction and Activity Patterns Using Motion-Activated Cameras

    SciTech Connect

    Hall, Derek B.; Greger, Paul D.

    2014-08-01

    We used motion-activated cameras to monitor the reproduction and patterns of activity of the Burrowing Owl (Athene cunicularia) above ground at 45 burrows in south-central Nevada during the breeding seasons of 1999, 2000, 2001, and 2005. The 37 broods, encompassing 180 young, raised over the four years represented an average of 4.9 young per successful breeding pair. Young and adult owls were detected at the burrow entrance at all times of the day and night, but adults were detected more frequently during afternoon/early evening than were young. Motion-activated cameras require less effort to implement than other techniques. Limitations include photographing only a small percentage of owl activity at the burrow; not detecting the actual number of eggs, young, or number fledged; and not being able to track individual owls over time. Further work is also necessary to compare the accuracy of productivity estimates generated from motion-activated cameras with other techniques.

  15. Vortex leading edge flap assembly for supersonic airplanes

    NASA Technical Reports Server (NTRS)

    Rudolph, Peter K. C. (Inventor)

    1997-01-01

    A leading edge flap (16) for supersonic transport airplanes is disclosed. In its stowed position, the leading edge flap forms the lower surface of the wing leading edge up to the horizontal center of the leading edge radius. For low speed operation, the vortex leading edge flap moves forward and rotates down. The upward curve of the flap leading edge triggers flow separation on the flap and rotational flow on the upper surface of the flap (vortex). The rounded shape of the upper fixed leading edge provides the conditions for a controlled reattachment of the flow on the upper wing surface and therefore a stable vortex. The vortex generates lift and a nose-up pitching moment. This improves maximum lift at low speed, reduces attitude for a given lift coefficient and improves lift to drag ratio. The mechanism (27) to move the vortex flap consists of two spanwise supports (24) with two diverging straight tracks (64 and 68) each and a screw drive mechanism (62) in the center of the flap panel (29). The flap motion is essentially normal to the airloads and therefore requires only low actuation forces.

  16. An aeroelastic instability provides a possible basis for the transition from gliding to flapping flight.

    PubMed

    Curet, Oscar M; Swartz, Sharon M; Breuer, Kenneth S

    2013-03-01

    The morphology, kinematics and stiffness properties of lifting surfaces play a key role in the aerodynamic performance of vertebrate flight. These surfaces, as a result of their flexible nature, may move both actively, owing to muscle contraction, and passively, in reaction to fluid forces. However, the nature and implications of this fluid-structure interaction are not well understood. Here, we study passive flight (flight with no active wing actuation) and explore a physical mechanism that leads to the emergence of a natural flapping motion. We model a vertebrate wing with a compliant shoulder and the ability to camber with an idealized physical model consisting of a cantilevered flat plate with a hinged trailing flap. We find that at low wind speed the wing is stationary, but at a critical speed the wing spontaneously flaps. The lift coefficient is significantly enhanced once the wing starts to oscillate, although this increase in lift generation is accompanied by an increase in drag. Flow visualization suggests that a strong leading edge vortex attached to the wing during downstroke is the primary mechanism responsible for the enhanced lift. The flapping instability we observe suggests a possible scenario for an evolutionary transition from gliding to powered flapping flight in animals that possess compliant wings capable of passive camber. Although the flapping state is accompanied by a lower lift-to-drag ratio, the increased lifting capability it confers might have enabled increased body mass, improved foraging performance and/or flight at lower speeds, any of which might have been selectively advantageous. PMID:23303221

  17. An aeroelastic instability provides a possible basis for the transition from gliding to flapping flight

    PubMed Central

    Curet, Oscar M.; Swartz, Sharon M.; Breuer, Kenneth S.

    2013-01-01

    The morphology, kinematics and stiffness properties of lifting surfaces play a key role in the aerodynamic performance of vertebrate flight. These surfaces, as a result of their flexible nature, may move both actively, owing to muscle contraction, and passively, in reaction to fluid forces. However, the nature and implications of this fluid–structure interaction are not well understood. Here, we study passive flight (flight with no active wing actuation) and explore a physical mechanism that leads to the emergence of a natural flapping motion. We model a vertebrate wing with a compliant shoulder and the ability to camber with an idealized physical model consisting of a cantilevered flat plate with a hinged trailing flap. We find that at low wind speed the wing is stationary, but at a critical speed the wing spontaneously flaps. The lift coefficient is significantly enhanced once the wing starts to oscillate, although this increase in lift generation is accompanied by an increase in drag. Flow visualization suggests that a strong leading edge vortex attached to the wing during downstroke is the primary mechanism responsible for the enhanced lift. The flapping instability we observe suggests a possible scenario for an evolutionary transition from gliding to powered flapping flight in animals that possess compliant wings capable of passive camber. Although the flapping state is accompanied by a lower lift-to-drag ratio, the increased lifting capability it confers might have enabled increased body mass, improved foraging performance and/or flight at lower speeds, any of which might have been selectively advantageous. PMID:23303221

  18. Piloted simulation study of two tilt-wing flap control concepts, phase 2

    NASA Technical Reports Server (NTRS)

    Birckelbaw, Lourdes G.; Corliss, Lloyd D.; Hindson, William S.; Churchill, Gary B.

    1994-01-01

    A two phase piloted simulation study has been conducted in the Ames Vertical Motion Simulator to investigate alternative wing and flap controls for tilt-wing aircraft. This report documents the flying qualities results and findings of the second phase of the piloted simulation study and describes the simulated tilt-wing aircraft, the flap control concepts, the experiment design and the evaluation tasks. The initial phase of the study compared the flying qualities of both a conventional programmed flap and an innovative geared flap. The second phase of the study introduced an alternate method of pilot control for the geared flap and further studied the flying qualities of the programmed flap and two geared flap configurations. In general, the pilot ratings showed little variation between the programmed flap and the geared flap control concepts. Some differences between the two control concepts were noticed and are discussed in this report. The geared flap configurations had very similar results. Although the geared flap concept has the potential to reduce or eliminate the pitch control power requirements from a tail rotor or a tail thruster at low speeds and in hover, the results did not show reduced tail thruster pitch control power usage with the geared flap configurations compared to the programmed flap configuration. The addition of pitch attitude stabilization in the second phase of simulation study greatly enhanced the aircraft flying qualities compared to the first phase.

  19. Keyhole Flap Nipple Reconstruction.

    PubMed

    Chen, Joseph I; Cash, Camille G; Iman, Al-Haj; Spiegel, Aldona J; Cronin, Ernest D

    2016-05-01

    Nipple-areola reconstruction is often one of the final but most challenging aspects of breast reconstruction. However, it is an integral and important component of breast reconstruction because it transforms the mound into a breast. We performed 133 nipple-areola reconstructions during a period of 4 years. Of these reconstructions, 76 of 133 nipple-areola complexes were reconstructed using the keyhole flap technique. The tissue used for the keyhole dermoadipose flap technique include transverse rectus abdominus myocutaneous flaps (60/76), latissimus dorsi flaps (15/76), or mastectomy skin flaps after tissue expanders (1/76). The average patient follow-up was 17 months. The design of the flap is based on a keyhole configuration. The base of the flap determines the width of the future nipple, whereas the length of the flap determines the projection. We try to match the projection of the contralateral nipple if present. The keyhole flap is simple to construct yet reliable. It provides good symmetry and projection and avoids the creation of new scars. The areola is then tattooed approximately 3 months after the nipple reconstruction. PMID:27579228

  20. Unwinding motion of a twisted active region filament

    SciTech Connect

    Yan, X. L.; Xue, Z. K.; Kong, D. F.; Liu, J. H.; Xu, C. L.

    2014-12-10

    To better understand the structures of active region filaments and the eruption process, we study an active region filament eruption in active region NOAA 11082 in detail on 2010 June 22. Before the filament eruption, the opposite unidirectional material flows appeared in succession along the spine of the filament. The rising of the filament triggered two B-class flares at the upper part of the filament. As the bright material was injected into the filament from the sites of the flares, the filament exhibited a rapid uplift accompanying the counterclockwise rotation of the filament body. From the expansion of the filament, we can see that the filament consisted of twisted magnetic field lines. The total twist of the filament is at least 5π obtained by using a time slice method. According to the morphology change during the filament eruption, it is found that the active region filament was a twisted flux rope and its unwinding motion was like a solar tornado. We also find that there was a continuous magnetic helicity injection before and during the filament eruption. It is confirmed that magnetic helicity can be transferred from the photosphere to the filament. Using the extrapolated potential fields, the average decay index of the background magnetic fields over the filament is 0.91. Consequently, these findings imply that the mechanism of solar filament eruption could be due to the kink instability and magnetic helicity accumulation.

  1. Repair of Fingertip Defect Using an Anterograde Pedicle Flap Based on the Dorsal Perforator

    PubMed Central

    Wei, Peng; Chen, Weiwei; Mei, Jin; Ding, Maochao; Yu, Yaling; Xi, Shanshan; Zhou, Renpeng

    2016-01-01

    Background: The purposes of this article are to introduce and assess the results of a long-term follow-up of using anterograde pedicle flap based on the dorsal branches of proper digital neurovascular bundles from the dorsum of the middle phalanx for the fingertip defect. Methods: Between February 2011 and December 2012, 31 patients underwent reconstruction of fingertip defects using a homodigital flap based on the dorsal perforator in the middle phalanx. The defect size ranged from 1.3 cm × 1.5 cm to 2.4 cm × 3.0 cm. During surgery, the flap was designed on the dorsal middle phalangeal region. The pedicle was a neurovascular bundle consisting of an artery, vein, and sensory nerve; the rotation of pedicle was <90 degrees. Results: The clinical results were satisfactory after 3 to 9 months of follow-up. The flaps were considered cosmetically acceptable by both patients and doctors. The sensory recovery was excellent, 2-point discrimination was 4.96 ± 1.47 mm, and the recovery of range of motion of the interphalangeal joints was very good. Conclusions: The anterograde island flap based on the dorsal branches of proper digital neurovascular bundles is an ideal aesthetic reconstruction method for fingertip defect. A 90-degree rotated island pedicle flap was very versatile, easy to design, and had good survival. This technique is simple with less damage to the donor site, without sacrificing the branch of the digital artery and nerve. The reliable source of blood supply and satisfactory recovery of sensation can be achieved without affecting the interphalangeal joint activity. PMID:27482478

  2. Motion verb sentences activate left posterior middle temporal cortex despite static context.

    PubMed

    Wallentin, Mikkel; Lund, Torben Ellegaard; Ostergaard, Svend; Ostergaard, Leif; Roepstorff, Andreas

    2005-04-25

    The left posterior middle temporal region, anterior to V5/MT, has been shown to be responsive both to images with implied motion, to simulated motion, and to motion verbs. In this study, we investigated whether sentence context alters the response of the left posterior middle temporal region. 'Fictive motion' sentences are sentences in which an inanimate subject noun, semantically incapable of self movement, is coupled with a motion verb, yielding an apparent semantic contradiction (e.g. 'The path comes into the garden.'). However, this context yields no less activation in the left posterior middle temporal region than sentences in which the motion can be applied to the subject noun. We speculate that the left posterior middle temporal region activity in fictive motion sentences reflects the fact that the hearer applies motion to the depicted scenario by scanning it egocentrically.

  3. Flow Over Swept Flaps and Flap Tips

    NASA Technical Reports Server (NTRS)

    Bradshaw, Peter; Buice, Carl U.

    1995-01-01

    Preliminary measurements have been made of the flow over the tip of an unswept wing flap. To achieve an acceptable Reynolds number based on flap chord, the flap chord was chosen equal to the chord of the main airfoil (c = 19 in. approx. 0.48 m). The model was mounted in a 30 in. x 30 in. wind tunnel running at up to 100 ft/sec. (30 m/s): severe wind-tunnel interference was accepted, and any computations would be done using the tunnel walls as the boundaries of the computational domain. Maximum Reynolds number based on flap chord and tunnel speed was about 1.O x lO(exp 6). The grant ended before a full set of measurements could be made, but the work done so far yields a useful picture of the flow. The vortex originates at about mid-chord on the flap and rises rapidly above the chord line. It has a concentrated core, with total pressure lower than the ambient static pressure, and there is no evidence of large-scale wandering. A simple method of model construction, giving light weight and excellent surface finish, was developed.

  4. Viewing the motion of human body parts activates different regions of premotor, temporal, and parietal cortex.

    PubMed

    Wheaton, Kylie J; Thompson, James C; Syngeniotis, Ari; Abbott, David F; Puce, Aina

    2004-05-01

    Activation of premotor and temporoparietal cortex occurs when we observe others movements, particularly relating to objects. Viewing the motion of different body parts without the context of an object has not been systematically evaluated. During a 3T fMRI study, 12 healthy subjects viewed human face, hand, and leg motion, which was not directed at or did not involve an object. Activation was identified relative to static images of the same human face, hand, and leg in both individual subject and group average data. Four clear activation foci emerged: (1) right MT/V5 activated to all forms of viewed motion; (2) right STS activated to face and leg motion; (3) ventral premotor cortex activated to face, hand, and leg motion in the right hemisphere and to leg motion in the left hemisphere; and (4) anterior intraparietal cortex (aIP) was active bilaterally to viewing hand motion and in the right hemisphere leg motion. In addition, in the group data, a somatotopic activation pattern for viewing face, hand, and leg motion occurred in right ventral premotor cortex. Activation patterns in STS and aIP were more complex--typically activation foci to viewing two types of human motion showed some overlap. Activation in individual subjects was similar; however, activation to hand motion also occurred in the STS with a variable location across subjects--explaining the lack of a clear activation focus in the group data. The data indicate that there are selective responses to viewing motion of different body parts in the human brain that are independent of object or tool use.

  5. Forelimb muscle function in pig-nosed turtles, Carettochelys insculpta: testing neuromotor conservation between rowing and flapping in swimming turtles.

    PubMed

    Rivera, Angela R V; Blob, Richard W

    2013-10-23

    Changes in muscle activation patterns can lead to new locomotor modes; however, neuromotor conservation-the evolution of new forms of locomotion through changes in structure without concurrent changes to underlying motor patterns-has been documented across diverse styles of locomotion. Animals that swim using appendages do so via rowing (anteroposterior oscilations) or flapping (dorsoventral oscilations). Yet few studies have compared motor patterns between these swimming modes. In swimming turtles, propulsion is generated exclusively by limbs. Kinematically, turtles swim using multiple styles of rowing (freshwater species), flapping (sea turtles) and a unique hybrid style with superficial similarity to flapping by sea turtles and characterized by increased dorsoventral motions of synchronously oscillated forelimbs that have been modified into flippers (Carettochelys insculpta). We compared forelimb motor patterns in four species of turtle (two rowers, Apalone ferox and Trachemys scripta; one flapper, Caretta caretta; and Carettochelys) and found that, despite kinematic differences, motor patterns were generally similar among species with a few notable exceptions: specifically, presence of variable bursts for pectoralis and triceps in Trachemys (though timing of the non-variable pectoralis burst was similar), and the timing of deltoideus activity in Carettochelys and Caretta compared with other taxa. The similarities in motor patterns we find for several muscles provide partial support for neuromotor conservation among turtles using diverse locomotor styles, but the differences implicate deltoideus as a prime contributor to flapping limb motions.

  6. Facial flap complications.

    PubMed

    Zoumalan, Richard A; Murakami, Craig S

    2012-06-01

    Knowledge of fundamental concepts can help decrease the chance of complications in plastic surgery. Local flap reconstruction for facial defects has many pitfalls. This article describes common complications in local flap reconstruction of the face and describes strategies that prevent problems.

  7. Does motion-related brain functional connectivity reflect both artifacts and genuine neural activity?

    PubMed

    Pujol, Jesus; Macià, Dídac; Blanco-Hinojo, Laura; Martínez-Vilavella, Gerard; Sunyer, Jordi; de la Torre, Rafael; Caixàs, Assumpta; Martín-Santos, Rocío; Deus, Joan; Harrison, Ben J

    2014-11-01

    Imaging research on functional connectivity is uniquely contributing to characterize the functional organization of the human brain. Functional connectivity measurements, however, may be significantly influenced by head motion that occurs during image acquisition. The identification of how motion influences such measurements is therefore highly relevant to the interpretation of a study's results. We have mapped the effect of head motion on functional connectivity in six different populations representing a wide range of potential influences of motion on functional connectivity. Group-level voxel-wise maps of the correlation between a summary head motion measurement and functional connectivity degree were estimated in 80 young adults, 71 children, 53 older adults, 20 patients with Down syndrome, 24 with Prader-Willi syndrome and 20 with Williams syndrome. In highly compliant young adults, motion correlated with functional connectivity measurements showing a system-specific anatomy involving the sensorimotor cortex, visual areas and default mode network. Further characterization was strongly indicative of these changes expressing genuine neural activity related to motion, as opposed to pure motion artifact. In the populations with larger head motion, results were more indicative of widespread artifacts, but showing notably distinct spatial distribution patterns. Group-level regression of motion effects was efficient in removing both generalized changes and changes putatively related to neural activity. Overall, this study endorses a relatively simple approach for mapping distinct effects of head motion on functional connectivity. Importantly, our findings support the intriguing hypothesis that a component of motion-related changes may reflect system-specific neural activity.

  8. Activity-based exploitation of Full Motion Video (FMV)

    NASA Astrophysics Data System (ADS)

    Kant, Shashi

    2012-06-01

    Video has been a game-changer in how US forces are able to find, track and defeat its adversaries. With millions of minutes of video being generated from an increasing number of sensor platforms, the DOD has stated that the rapid increase in video is overwhelming their analysts. The manpower required to view and garner useable information from the flood of video is unaffordable, especially in light of current fiscal restraints. "Search" within full-motion video has traditionally relied on human tagging of content, and video metadata, to provision filtering and locate segments of interest, in the context of analyst query. Our approach utilizes a novel machine-vision based approach to index FMV, using object recognition & tracking, events and activities detection. This approach enables FMV exploitation in real-time, as well as a forensic look-back within archives. This approach can help get the most information out of video sensor collection, help focus the attention of overburdened analysts form connections in activity over time and conserve national fiscal resources in exploiting FMV.

  9. Folding in and out: passive morphing in flapping wings.

    PubMed

    Stowers, Amanda K; Lentink, David

    2015-04-01

    We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover

  10. Active dipole clusters: From helical motion to fission.

    PubMed

    Kaiser, Andreas; Popowa, Katarina; Löwen, Hartmut

    2015-07-01

    The structure of a finite particle cluster is typically determined by total energy minimization. Here we consider the case where a cluster of soft-sphere dipoles becomes active, i.e., when the individual particles exhibit an additional self-propulsion along their dipole moments. We numerically solve the overdamped equations of motion for soft-sphere dipoles in a solvent. Starting from an initial metastable dipolar cluster, the self-propulsion generates a complex cluster dynamics. The final cluster state has in general a structure widely different to the initial one, the details depend on the model parameters and on the protocol of how the self-propulsion is turned on. The center of mass of the cluster moves on a helical path, the details of which are governed by the initial cluster magnetization. An instantaneous switch to a high self-propulsion leads to fission of the cluster. However, fission does not occur if the self-propulsion is increased slowly to high strengths. Our predictions can be verified through experiments with self-phoretic colloidal Janus particles and for macroscopic self-propelled dipoles in a highly viscous solvent.

  11. Implied motion because of instability in Hokusai Manga activates the human motion-sensitive extrastriate visual cortex: an fMRI study of the impact of visual art.

    PubMed

    Osaka, Naoyuki; Matsuyoshi, Daisuke; Ikeda, Takashi; Osaka, Mariko

    2010-03-10

    The recent development of cognitive neuroscience has invited inference about the neurosensory events underlying the experience of visual arts involving implied motion. We report functional magnetic resonance imaging study demonstrating activation of the human extrastriate motion-sensitive cortex by static images showing implied motion because of instability. We used static line-drawing cartoons of humans by Hokusai Katsushika (called 'Hokusai Manga'), an outstanding Japanese cartoonist as well as famous Ukiyoe artist. We found 'Hokusai Manga' with implied motion by depicting human bodies that are engaged in challenging tonic posture significantly activated the motion-sensitive visual cortex including MT+ in the human extrastriate cortex, while an illustration that does not imply motion, for either humans or objects, did not activate these areas under the same tasks. We conclude that motion-sensitive extrastriate cortex would be a critical region for perception of implied motion in instability.

  12. Unsteady aerodynamic modeling for arbitrary motions. [for active control techniques

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1977-01-01

    Results indicating that unsteady aerodynamic loads derived under the assumption of simple harmonic motions executed by airfoil or wing can be extended to arbitrary motions are summarized. The generalized Theodorsen (1953) function referable to loads due to simple harmonic oscillations of a wing section in incompressible flow, the Laplace inversion integral for unsteady aerodynamic loads, calculations of root loci of aeroelastic loads, and analysis of generalized compressible transient airloads are discussed.

  13. [The abdominal drop flap].

    PubMed

    Bodin, F; Liverneaux, P; Seigle-Murandi, F; Facca, S; Bruant-Rodier, C; Dissaux, C; Chaput, B

    2015-08-01

    The skin between the mastectomy scar and the future infra-mammary fold may be managed in different ways in delayed breast reconstruction using a DIEP (deep inferior epigastric perforator). Conserving this skin and positioning the flap skin paddle in the middle of the breast usually highlights skin color disparity because of two visible transition zones. Resection of the entire skin under the scar may be more aesthetic but limits direct closure possibility in case of flap failure. In order to benefit from both aesthetic result and safe surgical method, we propose the abdominal drop flap. The inferior thoracic skin flap is detached from the thoracic wall beyond the future infra-mammary fold, preserved and pushed under the breast.

  14. Total arm flap.

    PubMed

    Becker, D W

    1987-11-01

    The development of an unusual and rarely indicated total arm flap is described in the context of widely indicated and automatically used principles passed down by the recognized father of plastic surgery, Sir Harold G. Gillies.

  15. Flapping of Insectile Wings

    NASA Astrophysics Data System (ADS)

    Huang, Yangyang; Kanso, Eva

    2015-11-01

    Insects use flight muscles attached at the base of the wings to produce impressive wing flapping frequencies. Yet the effects of muscle stiffness on the performance of insect wings remain unclear. Here, we construct an insectile wing model, consisting of two rigid wings connected at their base by an elastic torsional spring and submerged in an oscillatory flow. The wing system is free to rotate and flap. We first explore the extent to which the flyer can withstand roll perturbations, then study its flapping behavior and performance as a function of spring stiffness. We find an optimal range of spring stiffness that results in large flapping amplitudes, high force generation and good storage of elastic energy. We conclude by conjecturing that insects may select and adjust the muscle spring stiffness to achieve desired movement. These findings may have significant implications on the design principles of wings in micro air-vehicles.

  16. Evaluation of flexible flapping wing concept

    NASA Astrophysics Data System (ADS)

    Rakotomamonjy, Thomas; Le Moing, Thierry; Danet, Brieuc; Gadoullet, Xavier; Osmont, Daniel; Dupont, Marc

    2009-03-01

    ONERA - The French Aerospace Lab - has launched an internal program on biologically-inspired Micro Air Vehicles (MAVs), covering many research topics such as unsteady aerodynamics, actuation, structural dynamics or control. The aim is to better understand the flapping flight performed in nature by insects, and to control state of the art technologies and applications in this field. For that purpose, a flight-dynamics oriented simulation model of a flapping-wing concept has been developed. This model, called OSCAB, features a body and two wings along which the aerodynamics efforts are integrated, so as to determine the global motion of the MAV. The model has been improved by taking into account the flexibility of the wings (flexion of the leading edge and passive torsion of the wings, induced by the flapping motion itself under wing inertia). Thus, it becomes possible to estimate the coupling between flexibility and the aerodynamic forces. Furthermore, the model shows that using elastic properties of the wings allows a diminution of the mechanical energy needed for wings motion, and a reduction of the number of actuators to be implanted into the MAV.

  17. Repair of large full-thickness cartilage defect by activating endogenous peripheral blood stem cells and autologous periosteum flap transplantation combined with patellofemoral realignment.

    PubMed

    Fu, Wei-Li; Ao, Ying-Fang; Ke, Xiao-Yan; Zheng, Zhuo-Zhao; Gong, Xi; Jiang, Dong; Yu, Jia-Kuo

    2014-03-01

    Minimal-invasive procedure and one-step surgery offer autologous mesenchymal stem cells derived from peripheral blood (PB-MSCs) a promising prospective in the field of cartilage regeneration. We report a case of a 19-year-old male athlete of kickboxing with ICRS grade IV chondral lesions at the 60° region of lateral femoral trochlea, which was repaired by activating endogenous PB-MSCs plus autologous periosteum flap transplantation combined with correcting the patellofemoral malalignment. After a 7.5 year follow-up, the result showed that the patient returned to competitive kickboxing. Second-look under arthroscopy showed a smooth surface at 8 months postoperation. The IKDC 2000 subjective score, Lysholm score and Tegner score were 95, 98 and 9 respectively at the final follow up. CT and MRI evaluations showed a significant improvement compared with those of pre-operation.

  18. Hydrodynamic schooling of flapping swimmers

    DOE PAGES

    Becker, Alexander D.; Masoud, Hassan; Newbolt, Joel W.; Shelley, Michael; Ristroph, Leif

    2015-10-06

    Fish schools and bird flocks are fascinating examples of collective behaviours in which many individuals generate and interact with complex flows. Motivated by animal groups on the move, here we explore how the locomotion of many bodies emerges from their flow-mediated interactions. Through experiments and simulations of arrays of flapping wings that propel within a collective wake, we discover distinct modes characterized by the group swimming speed and the spatial phase shift between trajectories of neighbouring wings. For identical flapping motions, slow and fast modes coexist and correspond to constructive and destructive wing–wake interactions. Simulations show that swimming in amore » group can enhance speed and save power, and we capture the key phenomena in a mathematical model based on memory or the storage and recollection of information in the flow field. Lastly, these results also show that fluid dynamic interactions alone are sufficient to generate coherent collective locomotion, and thus might suggest new ways to characterize the role of flows in animal groups.« less

  19. Hydrodynamic schooling of flapping swimmers

    SciTech Connect

    Becker, Alexander D.; Masoud, Hassan; Newbolt, Joel W.; Shelley, Michael; Ristroph, Leif

    2015-10-06

    Fish schools and bird flocks are fascinating examples of collective behaviours in which many individuals generate and interact with complex flows. Motivated by animal groups on the move, here we explore how the locomotion of many bodies emerges from their flow-mediated interactions. Through experiments and simulations of arrays of flapping wings that propel within a collective wake, we discover distinct modes characterized by the group swimming speed and the spatial phase shift between trajectories of neighbouring wings. For identical flapping motions, slow and fast modes coexist and correspond to constructive and destructive wing–wake interactions. Simulations show that swimming in a group can enhance speed and save power, and we capture the key phenomena in a mathematical model based on memory or the storage and recollection of information in the flow field. Lastly, these results also show that fluid dynamic interactions alone are sufficient to generate coherent collective locomotion, and thus might suggest new ways to characterize the role of flows in animal groups.

  20. Hydrodynamic schooling of flapping swimmers

    PubMed Central

    Becker, Alexander D.; Masoud, Hassan; Newbolt, Joel W.; Shelley, Michael; Ristroph, Leif

    2015-01-01

    Fish schools and bird flocks are fascinating examples of collective behaviours in which many individuals generate and interact with complex flows. Motivated by animal groups on the move, here we explore how the locomotion of many bodies emerges from their flow-mediated interactions. Through experiments and simulations of arrays of flapping wings that propel within a collective wake, we discover distinct modes characterized by the group swimming speed and the spatial phase shift between trajectories of neighbouring wings. For identical flapping motions, slow and fast modes coexist and correspond to constructive and destructive wing–wake interactions. Simulations show that swimming in a group can enhance speed and save power, and we capture the key phenomena in a mathematical model based on memory or the storage and recollection of information in the flow field. These results also show that fluid dynamic interactions alone are sufficient to generate coherent collective locomotion, and thus might suggest new ways to characterize the role of flows in animal groups. PMID:26439509

  1. Hydrodynamic schooling of flapping swimmers

    NASA Astrophysics Data System (ADS)

    Becker, Alexander D.; Masoud, Hassan; Newbolt, Joel W.; Shelley, Michael; Ristroph, Leif

    2015-10-01

    Fish schools and bird flocks are fascinating examples of collective behaviours in which many individuals generate and interact with complex flows. Motivated by animal groups on the move, here we explore how the locomotion of many bodies emerges from their flow-mediated interactions. Through experiments and simulations of arrays of flapping wings that propel within a collective wake, we discover distinct modes characterized by the group swimming speed and the spatial phase shift between trajectories of neighbouring wings. For identical flapping motions, slow and fast modes coexist and correspond to constructive and destructive wing-wake interactions. Simulations show that swimming in a group can enhance speed and save power, and we capture the key phenomena in a mathematical model based on memory or the storage and recollection of information in the flow field. These results also show that fluid dynamic interactions alone are sufficient to generate coherent collective locomotion, and thus might suggest new ways to characterize the role of flows in animal groups.

  2. Effects of Wing Platform on the Aerodynamic Performance of Finite-Span Flapping Wings

    NASA Astrophysics Data System (ADS)

    Yu, Meilin; Wang, Z. J.; Hu, Hui

    2010-11-01

    A numerical study is conducted to investigate the effects of wing platform on the aerodynamics performance of finite-span flapping wings. A three-dimensional high-order Navier-Stokes compressible flow solver was developed using the spectral difference method and dynamic grids. An AUSM^+-up Riemann solver was implemented to simulate the unsteady low Mach number flows over finite-span flapping wings with explicit third order Runge-Kutta time integration. The studied finite-span flapping wings, which include a rectangular flapping wing, an elliptic flapping wing and a bio-inspired flapping wing, have the same wing span, aspect ratio of the platform and the characteristics of the flapping motion (i.e., sinusoidal trajectory of the flapping wing tip, Strouhal number and reduced frequency). In the present study, the Strouhul number (Str) of the finite-span flapping wings was selected to be well within the optimal range usually used by flying insects and birds and swimming fishes (i.e., 0.2 < Str < 0.4). The effects of the wing platform on the aerodynamics performance of the finite-span flapping wings were elucidated in the terms of the evolutions and dynamic interaction between the leading edge vortices (LEV) and the wing tip vortices as well as the resultant aerodynamic forces (both lift and thrust) generated by the flapping wings.

  3. Postural activity and motion sickness during video game play in children and adults.

    PubMed

    Chang, Chih-Hui; Pan, Wu-Wen; Tseng, Li-Ya; Stoffregen, Thomas A

    2012-03-01

    Research has confirmed that console video games give rise to motion sickness in many adults. During exposure to console video games, there are differences in postural activity (movement of the head and torso) between participants who later experience motion sickness and those who do not, confirming a prediction of the postural instability theory of motion sickness. Previous research has not addressed relations between video games, movement and motion sickness in children. We evaluated the nauseogenic properties of a commercially available console video game in both adults and 10-year-old children. Individuals played the game for up to 50 min and were instructed to discontinue immediately if they experienced any symptoms of motion sickness, however mild. During game play, we monitored movement of the head and torso. Motion sickness was reported by 67% of adults and by 56% of children; these rates did not differ. As a group, children moved more than adults. Across age groups, the positional variability of the head and torso increased over time during game play. In addition, we found differences in movement between participants who later reported motion sickness and those who did not. Some of these differences were general across age groups but we also found significant differences between the movement of adults and children who later reported motion sickness. The results confirm that console video games can induce motion sickness in children and demonstrate that changes in postural activity precede the onset of subjective symptoms of motion sickness in children.

  4. Effective temperature and spontaneous collective motion of active matter

    NASA Astrophysics Data System (ADS)

    Wang, Shenshen; Wolynes, Peter

    2012-02-01

    Spontaneous directed motion, a hallmark of cell biology, is unusual in classical statistical physics. Here we study, using both numerical and analytical methods, organized motion in models of the cytoskeleton in which constituents are driven by energy-consuming motors. Although systems driven by small-step motors are described by an effective temperature and are thus quiescent, at higher order in step size, both homogeneous and inhomogeneous, flowing and oscillating behavior emerges. Motors that respond with a negative susceptibility to imposed forces lead to an apparent negative temperature system in which beautiful structures form resembling the asters seen in cell division.

  5. Flapping flexible fish

    NASA Astrophysics Data System (ADS)

    Root, Robert G.; Courtland, Hayden-William; Shepherd, William; Long, John H.

    In order to analyze and model the body kinematics used by fish in a wide range of swimming behaviors, we developed a technique to separate the periodic whole-body motions that characterize steady swimming from the secular motions that characterize changes in whole-body shape. We applied this harmonic analysis technique to the study of the forward and backward swimming of lamprey. We found that in order to vary the unsteadiness of swimming, lamprey superimpose periodic and secular components of their body motion, modulate the patterns and magnitudes of those components, and change shape. These kinematic results suggest the following hydromechanical hypothesis: steady swimming is a maneuver that requires active suppression of secular body reconfigurations.

  6. The effects of Juchumseogi and Juchumseo Jireugi motions of taekwondo on muscle activation of paraspinal muscles

    PubMed Central

    Baek, Jongmyeng; Lee, Jaeseok; Kim, Jonghyun; Kim, Jeonghun; Han, Dongwook; Byun, Sunghak

    2015-01-01

    [Purpose] The purpose of this study is to examine the effects of Juchumseogi and Juchumseo Jireugi motions on muscle activation of the paraspinal muscles. [Subjects] The subjects of this study were 20 healthy male students who listened to an explanation of the study methods and the purpose of the experiment, and agreed to participate in the study. [Methods] Muscle activation measurements of the paraspinal muscles at C3, T7, and L3 were taken while standing still and while performing Juchumseogi and Juchumseo Jireugi movements. The Juchumseogi and Juchumseo Jireugi motions were performed 3 times, and its mean value was used for analysis. [Results] The right and left muscle activation of paraspinal muscles induced by Juchumseogi and Juchumseo Jireugi motions in C3 and T7 were significantly higher than those induced by just standing. Muscle activation of paraspinal muscles induced by Juchumseo Jireugi motions in C3, T7, and L3 were significantly higher than those induced by Juchumseogi alone. The right and left muscle activation of paraspinal muscles induced by Juchumseo Jireugi motion in C3, T7, and L3 were significantly higher than those induced by standing and Juchumseogi alone. [Conclusion] This study demonstrated that Juchumseogi and Juchumseo Jireugi motions of Taekwondo could increase muscle activation of paraspinal muscles, and Juchumseo Jireugi motions were more effective for enhancing muscle activation of paraspinal muscles. PMID:26504295

  7. The effects of Juchumseogi and Juchumseo Jireugi motions of taekwondo on muscle activation of paraspinal muscles.

    PubMed

    Baek, Jongmyeng; Lee, Jaeseok; Kim, Jonghyun; Kim, Jeonghun; Han, Dongwook; Byun, Sunghak

    2015-09-01

    [Purpose] The purpose of this study is to examine the effects of Juchumseogi and Juchumseo Jireugi motions on muscle activation of the paraspinal muscles. [Subjects] The subjects of this study were 20 healthy male students who listened to an explanation of the study methods and the purpose of the experiment, and agreed to participate in the study. [Methods] Muscle activation measurements of the paraspinal muscles at C3, T7, and L3 were taken while standing still and while performing Juchumseogi and Juchumseo Jireugi movements. The Juchumseogi and Juchumseo Jireugi motions were performed 3 times, and its mean value was used for analysis. [Results] The right and left muscle activation of paraspinal muscles induced by Juchumseogi and Juchumseo Jireugi motions in C3 and T7 were significantly higher than those induced by just standing. Muscle activation of paraspinal muscles induced by Juchumseo Jireugi motions in C3, T7, and L3 were significantly higher than those induced by Juchumseogi alone. The right and left muscle activation of paraspinal muscles induced by Juchumseo Jireugi motion in C3, T7, and L3 were significantly higher than those induced by standing and Juchumseogi alone. [Conclusion] This study demonstrated that Juchumseogi and Juchumseo Jireugi motions of Taekwondo could increase muscle activation of paraspinal muscles, and Juchumseo Jireugi motions were more effective for enhancing muscle activation of paraspinal muscles.

  8. Blowing Flap Experiment: PIV Measurements

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Stead, Daniel J.; Bremmer, David M.

    2004-01-01

    PIV measurements of the flow in the region of a flap side edge are presented for several flap configurations. The test model is a NACA 63(sub 2)-215 Hicks Mod-B main element airfoil with a half-span Fowler flap. Air is blown from small slots located along the flap side edge on either the top, bottom or side surfaces. The test set up is described and flow measurements for a baseline and three blowing flap configurations are presented. The effects that the flap tip jets have on the structure of the flap side edge flow are discussed for each of the flap configurations tested. The results indicate that blowing air from a slot located along the top surface of the flap greatly weakened the top vortex system and pushed it further off the top surface. Blowing from the bottom flap surface kept the strong side vortex further outboard while blowing from the side surface only strengthened the flap vortex system. It is concluded that blowing from the top or bottom surfaces of the flap may lead to a reduction of flap side edge noise.

  9. Optimization of Kinematics of a Flapping Wing Mechanism

    NASA Astrophysics Data System (ADS)

    George, Ryan; Thomson, Scott; Mattson, Christopher; Colton, Mark; Tree, Mike

    2010-11-01

    Flapping flight offers several potential advantages over conventional fixed wing flight, such as agility and maneuverability in confined spaces, potentially decreased noise and detectability, and hovering capability. In this presentation, a water tunnel-based flapping wing apparatus is introduced that allows for arbitrary wing trajectories in three rotational degrees of freedom and simultaneous measurements of lift and thrust production. An optimal flapping trajectory for takeoff is found using hardware-in-the-loop optimization methodology. Wing motion derived from high-speed imaging of a ladybug during takeoff is used as a first iteration of the hardware-in-the-loop optimization. Using real-time force measurements and a gradient-based optimization approach, the algorithm searches for the optimal trajectory for a variety of parameters such as lift or efficiency. Hardware performance is assessed. Results from the optimization routine, including the final flapping trajectory are reported for both rigid and compliant wings.

  10. Wing compliance in self-propelled flapping flyers

    NASA Astrophysics Data System (ADS)

    Ramananarivo, Sophie; Thiria, Benjamin; Godoy-Diana, Ramiro

    2010-11-01

    Wing flexibility governs the flying performance of flapping wing flyers. Here we use the self-propelled flapping-wing model mounted on a "merry-go-round" described by Thiria and Godoy-Diana (Phys. Rev. E 82, 015303, 2010) to investigate the effect of chord-wise wing compliance on the propulsive performance of the system. The bending of the wings, which is driven mainly by wing inertia in the present experiments, redistributes the aerodynamic forces engendered by the flapping motion and improves the efficiency of the system for a wide range of wing flexibilities and flapping frequencies. A detailed analysis of the phase dynamics between the leading and trailing edges of the wings allows us to pinpoint the mechanisms that limit the beneficial effect of wing compliance.

  11. Analysis of neck muscle activity and comparison of head movement and body movement during rotational motion.

    PubMed

    Sirikantharajah, Shahini; Valter McConville, Kristiina M; Zolfaghari, Nika

    2015-08-01

    The neck is a very delicate part of the body that is highly prone to whiplash injuries, during jerk. A lot of the research relating to whiplash injuries performed to date has been tested in environments with linear motions and have mostly applied their work to car collisions. Whiplash injuries can also affect disabled individuals during falls, bed transfers, and while travelling in wheelchairs. The primary objective of this paper was to focus on neck and body behaviour during rotational motion, rather than linear motion which has been often associated with car collisions. This paper takes the current motion signal processing technique a step further by computing the differential between head and body motion. Neck electromyogram (EMG) and angular velocity data of the head and body were acquired simultaneously from 20 subjects, as they were rotated 45 degrees in the forward pitch plane, with and without visual input, in a motion simulator. The centre of rotation (COR) on the simulator was located behind the subject Results showed that neck muscle behaviour was affected by the forward rotations, as well as visual input. Anterior neck muscles were most active during forward rotations and trials including VR. Maximum effective muscle power and activity of 10.54% and 55.72 (mV/mV)·s were reached respectively. Furthermore, during forward rotations the motion profiles started off with dominance in body motion, followed by dominance in head motion.

  12. Analysis of neck muscle activity and comparison of head movement and body movement during rotational motion.

    PubMed

    Sirikantharajah, Shahini; Valter McConville, Kristiina M; Zolfaghari, Nika

    2015-08-01

    The neck is a very delicate part of the body that is highly prone to whiplash injuries, during jerk. A lot of the research relating to whiplash injuries performed to date has been tested in environments with linear motions and have mostly applied their work to car collisions. Whiplash injuries can also affect disabled individuals during falls, bed transfers, and while travelling in wheelchairs. The primary objective of this paper was to focus on neck and body behaviour during rotational motion, rather than linear motion which has been often associated with car collisions. This paper takes the current motion signal processing technique a step further by computing the differential between head and body motion. Neck electromyogram (EMG) and angular velocity data of the head and body were acquired simultaneously from 20 subjects, as they were rotated 45 degrees in the forward pitch plane, with and without visual input, in a motion simulator. The centre of rotation (COR) on the simulator was located behind the subject Results showed that neck muscle behaviour was affected by the forward rotations, as well as visual input. Anterior neck muscles were most active during forward rotations and trials including VR. Maximum effective muscle power and activity of 10.54% and 55.72 (mV/mV)·s were reached respectively. Furthermore, during forward rotations the motion profiles started off with dominance in body motion, followed by dominance in head motion. PMID:26737049

  13. Effects of attention and perceptual uncertainty on cerebellar activity during visual motion perception.

    PubMed

    Baumann, Oliver; Mattingley, Jason B

    2014-02-01

    Recent clinical and neuroimaging studies have revealed that the human cerebellum plays a role in visual motion perception, but the nature of its contribution to this function is not understood. Some reports suggest that the cerebellum might facilitate motion perception by aiding attentive tracking of visual objects. Others have identified a particular role for the cerebellum in discriminating motion signals in perceptually uncertain conditions. Here, we used functional magnetic resonance imaging to determine the degree to which cerebellar involvement in visual motion perception can be explained by a role in sustained attentive tracking of moving stimuli in contrast to a role in visual motion discrimination. While holding the visual displays constant, we manipulated attention by having participants attend covertly to a field of random-dot motion or a colored spot at fixation. Perceptual uncertainty was manipulated by varying the percentage of signal dots contained within the random-dot arrays. We found that attention to motion under high perceptual uncertainty was associated with strong activity in left cerebellar lobules VI and VII. By contrast, attending to motion under low perceptual uncertainty did not cause differential activation in the cerebellum. We found no evidence to support the suggestion that the cerebellum is involved in simple attentive tracking of salient moving objects. Instead, our results indicate that specific subregions of the cerebellum are involved in facilitating the detection and discrimination of task-relevant moving objects under conditions of high perceptual uncertainty. We conclude that the cerebellum aids motion perception under conditions of high perceptual demand.

  14. Tuning active Brownian motion with shot-noise energy pulses

    NASA Astrophysics Data System (ADS)

    Fiasconaro, Alessandro; Gudowska-Nowak, Ewa; Ebeling, Werner

    2009-01-01

    The main aim of this work is to explore the possibility of modeling the biological energy support mediated by absorption of ATP (adenosine triphosphate) as an energetic shot noise. We develop a general model with discrete input of energy pulses and study shot-noise-driven ratchets. We consider these ratchets as prototypes of Brownian motors driven by energy-rich ATP molecules. Our model is a stochastic machine able to acquire energy from the environment and convert it into kinetic energy of motion. We present characteristic features and demonstrate the possibility of tuning these motors by adapting the mean frequency of the discrete energy inputs, which are described as a special shot noise. In particular, the effect of stochastically driven directionality and uphill flux in systems acquiring energy from the shot noise is analyzed. As a possible application we consider the motion of kinesin on a microtubule under a constant load force.

  15. Experimental investigation and modeling of time resolved thrust of a flapping wing aircraft

    NASA Astrophysics Data System (ADS)

    Apker, Thomas B.

    This work presents a novel method of measuring the unsteady thrust of a hovering flapping wing vehicle and the development of phenomenological models to simulate it. The measurements were taken using a balance beam with the flapping wings mounted at one end and a counterweight plus an accelerometer mounted at the other. The trust axis of the flapping wings was mounted vertically, and the counterweight was adjusted to balance the weight and average thrust of the flapping wings. An accelerometer mounted above the counterweight measured the unsteady thrust. This method decoupled the force sensing element from the mass of the flapping wings, as opposed to standard force sensors that use a linear spring. This study showed that the spectral content of the flapping wings extended to 15 times the flapping frequency, well above the resonant frequency of the mass-spring-damper system formed by a load cell and flapping mechanism. High speed video of the wings was used to determine the motion of the flexible structure. This motion was used to develop phenomenological linear models of flapping wing thrust generation. The results show that this approach to linear modeling produces a system of equations that can be used for flight dynamics simulation and controller design.

  16. Bilobed flap in sole surgery

    SciTech Connect

    Sanchez-Conejo-Mir, J.; Bueno Montes, J.; Moreno Gimenez, J.C.; Camacho-Martinez, F.

    1985-09-01

    The bilobed flap is a simple reconstructive technique principally used to correct substantial defects in the facial region. The authors present their experience with this local flap in the difficult plantar area, with excellent short-term functional results. They describe the special characteristics of the bilobed flap in this zone, and comment on its indications and possible complications.

  17. Physical Activity Recognition Based on Motion in Images Acquired by a Wearable Camera.

    PubMed

    Zhang, Hong; Li, Lu; Jia, Wenyan; Fernstrom, John D; Sclabassi, Robert J; Mao, Zhi-Hong; Sun, Mingui

    2011-06-01

    A new technique to extract and evaluate physical activity patterns from image sequences captured by a wearable camera is presented in this paper. Unlike standard activity recognition schemes, the video data captured by our device do not include the wearer him/herself. The physical activity of the wearer, such as walking or exercising, is analyzed indirectly through the camera motion extracted from the acquired video frames. Two key tasks, pixel correspondence identification and motion feature extraction, are studied to recognize activity patterns. We utilize a multiscale approach to identify pixel correspondences. When compared with the existing methods such as the Good Features detector and the Speed-up Robust Feature (SURF) detector, our technique is more accurate and computationally efficient. Once the pixel correspondences are determined which define representative motion vectors, we build a set of activity pattern features based on motion statistics in each frame. Finally, the physical activity of the person wearing a camera is determined according to the global motion distribution in the video. Our algorithms are tested using different machine learning techniques such as the K-Nearest Neighbor (KNN), Naive Bayesian and Support Vector Machine (SVM). The results show that many types of physical activities can be recognized from field acquired real-world video. Our results also indicate that, with a design of specific motion features in the input vectors, different classifiers can be used successfully with similar performances.

  18. Physical Activity Recognition Based on Motion in Images Acquired by a Wearable Camera

    PubMed Central

    Zhang, Hong; Li, Lu; Jia, Wenyan; Fernstrom, John D.; Sclabassi, Robert J.; Mao, Zhi-Hong; Sun, Mingui

    2011-01-01

    A new technique to extract and evaluate physical activity patterns from image sequences captured by a wearable camera is presented in this paper. Unlike standard activity recognition schemes, the video data captured by our device do not include the wearer him/herself. The physical activity of the wearer, such as walking or exercising, is analyzed indirectly through the camera motion extracted from the acquired video frames. Two key tasks, pixel correspondence identification and motion feature extraction, are studied to recognize activity patterns. We utilize a multiscale approach to identify pixel correspondences. When compared with the existing methods such as the Good Features detector and the Speed-up Robust Feature (SURF) detector, our technique is more accurate and computationally efficient. Once the pixel correspondences are determined which define representative motion vectors, we build a set of activity pattern features based on motion statistics in each frame. Finally, the physical activity of the person wearing a camera is determined according to the global motion distribution in the video. Our algorithms are tested using different machine learning techniques such as the K-Nearest Neighbor (KNN), Naive Bayesian and Support Vector Machine (SVM). The results show that many types of physical activities can be recognized from field acquired real-world video. Our results also indicate that, with a design of specific motion features in the input vectors, different classifiers can be used successfully with similar performances. PMID:21779142

  19. Motion sickness susceptibility in parabolic flight and velocity storage activity

    NASA Technical Reports Server (NTRS)

    Dizio, Paul; Lackner, James R.

    1991-01-01

    In parabolic flight experiments, postrotary nystagmus is as found to be differentially suppressed in free fall (G) and in a high gravitoinertial force (1.8 G) background relative to 1 G. In addition, the influence of postrotary head movements on nystagmus suppression was found to be contingent on G-dependency of the velocity storage and dumping mechanisms. Here, susceptibility to motion sickness during head movements in 0 G and 1.8 G was rank-correlated with the following: (1) the decay time constant of the slow phase velocity of postrotary nystagmus under 1 G, no head movement, baseline conditions, (2) the extent of time constant reduction elicited in 0 G and 1.8 G; (3) the extent of time constant reduction elicited by head tilts in 1 G; and (4) changes in the extent of time constants reduction in 0 G and 1.8 G over repeated tests. Susceptibility was significantly correlated with the extent to which a head movement reduced the time constant in 1 G, was weakly correlated with the baseline time constant, but was not correlated with the extent of reduction in 0 G or 1.8 G. This pattern suggests a link between mechanisms evoking symptoms of space motion sickness and the mechanisms of velocity storage and dumping. Experimental means of evaluating this link are described.

  20. Effects of vascular endothelial growth factor on survival of surgical flaps: a review of experimental studies.

    PubMed

    Fang, Taolin; Lineaweaver, William C; Chen, Michael B; Kisner, Carson; Zhang, Feng

    2014-01-01

    Partial or complete necrosis of skin flaps remains a significant problem in plastic and reconstructive surgery. Growth factors have shown promise in improving flap survival through increased angiogenesis and blood supply to the flap. Vascular endothelial growth factor (VEGF) is the most widely investigated and successful one. But the mechanisms of the effects are still not very clear. In the course of a series of experiments, we indicated that tissue survival of surgical flaps could be improved by both preoperative (sustained phase effect) and intraoperative (acute phase effect) application of VEGF. We reviewed both experimental and clinical investigations on the use of VEGF with surgical flaps to summarize the evidence of both phases of VEGF activity in promotion of flaps survival in detail. With the combinations of acute and sustained phases of effects, VEGF protein and gene, VEGF morphologic actions, and VEGF histochemical modulations suggest a pattern of VEGF activity that can be superimposed on classic descriptive mechanisms of tissue survival of flaps.

  1. Local Flaps of The Hand

    PubMed Central

    Rehim, Shady A.; Chung, Kevin C.

    2014-01-01

    Synopsis A local flap consists of skin and subcutaneous tissue that is harvested from a site nearby a given defect while maintaining its intrinsic blood supply. When a soft tissue defect of the hand is not amenable to primary closure or skin grafting, local skin flaps can be a used as a reliable source of soft tissue replacement that replaces like with like. Flaps are categorized based on their composition, method of transfer, flap design and blood supply, yet flap circulation is considered the most critical factor for the flap survival. This article reviews the classification of local skin flaps of the hand and offers a practical reconstructive approach for several soft tissue defects of the hand and digits. PMID:24731606

  2. Noise Reduction of Aircraft Flap

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V. (Inventor); Brooks, Thomas F. (Inventor)

    2009-01-01

    A reduction in noise radiating from a side of a deployed aircraft flap is achieved by locating a slot adjacent the side of the flap, and then forcing air out through the slot with a suitable mechanism. One, two or even three or more slots are possible, where the slot is located at one;or more locations selected from a group of locations comprising a top surface of the flap, a bottom surface of the flap, an intersection of the top and side surface of the flap, an intersection of the bottom and side surfaces of the flap, and a side surface of the flap. In at least one embodiment the slot is substantially rectangular. A device for adjusting a rate of the air forced out through the slot can also be provided.

  3. Tracking of EEG activity using motion estimation to understand brain wiring.

    PubMed

    Nisar, Humaira; Malik, Aamir Saeed; Ullah, Rafi; Shim, Seong-O; Bawakid, Abdullah; Khan, Muhammad Burhan; Subhani, Ahmad Rauf

    2015-01-01

    The fundamental step in brain research deals with recording electroencephalogram (EEG) signals and then investigating the recorded signals quantitatively. Topographic EEG (visual spatial representation of EEG signal) is commonly referred to as brain topomaps or brain EEG maps. In this chapter, full search full search block motion estimation algorithm has been employed to track the brain activity in brain topomaps to understand the mechanism of brain wiring. The behavior of EEG topomaps is examined throughout a particular brain activation with respect to time. Motion vectors are used to track the brain activation over the scalp during the activation period. Using motion estimation it is possible to track the path from the starting point of activation to the final point of activation. Thus it is possible to track the path of a signal across various lobes.

  4. Aerodynamics and flight performance of flapping wing micro air vehicles

    NASA Astrophysics Data System (ADS)

    Silin, Dmytro

    Research efforts in this dissertation address aerodynamics and flight performance of flapping wing aircraft (ornithopters). Flapping wing aerodynamics was studied for various wing sizes, flapping frequencies, airspeeds, and angles of attack. Tested wings possessed both camber and dihedral. Experimental results were analyzed in the framework of momentum theory. Aerodynamic coefficients and Reynolds number are defined using a reference velocity as a vector sum of a freestream velocity and a strokeaveraged wingtip velocity. No abrupt stall was observed in flapping wings for the angle of attack up to vertical. If was found that in the presence of a freestream lift of a flapping wing in vertical position is higher than the propulsive thrust. Camber and dihedral increased both lift and thrust. Lift-curve slope, and maximum lift coefficient increased with Reynolds number. Performance model of an ornithopter was developed. Parametric studies of steady level flight of ornithopters with, and without a tail were performed. A model was proposed to account for wing-sizing effects during hover. Three micro ornithopter designs were presented. Ornithopter flight testing and data-logging was performed using a telemetry acquisition system, as well as motion capture technology. The ability of ornithopter for a sustained flight and a presence of passive aerodynamic stability were shown. Flight data were compared with performance simulations. Close agreement in terms of airspeed and flapping frequency was observed.

  5. sEMG during Whole-Body Vibration Contains Motion Artifacts and Reflex Activity

    PubMed Central

    Lienhard, Karin; Cabasson, Aline; Meste, Olivier; Colson, Serge S.

    2015-01-01

    The purpose of this study was to determine whether the excessive spikes observed in the surface electromyography (sEMG) spectrum recorded during whole-body vibration (WBV) exercises contain motion artifacts and/or reflex activity. The occurrence of motion artifacts was tested by electrical recordings of the patella. The involvement of reflex activity was investigated by analyzing the magnitude of the isolated spikes during changes in voluntary background muscle activity. Eighteen physically active volunteers performed static squats while the sEMG was measured of five lower limb muscles during vertical WBV using no load and an additional load of 33 kg. In order to record motion artifacts during WBV, a pair of electrodes was positioned on the patella with several layers of tape between skin and electrodes. Spectral analysis of the patella signal revealed recordings of motion artifacts as high peaks at the vibration frequency (fundamental) and marginal peaks at the multiple harmonics were observed. For the sEMG recordings, the root mean square of the spikes increased with increasing additional loads (p < 0.05), and was significantly correlated to the sEMG signal without the spikes of the respective muscle (r range: 0.54 - 0.92, p < 0.05). This finding indicates that reflex activity might be contained in the isolated spikes, as identical behavior has been found for stretch reflex responses evoked during direct vibration. In conclusion, the spikes visible in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activity. Key points The spikes observed in the sEMG spectrum during WBV exercises contain motion artifacts and possibly reflex activity The motion artifacts are more pronounced in the first spike than the following spikes in the sEMG spectrum Reflex activity during WBV exercises is enhanced with an additional load of approximately 50% of the body mass PMID:25729290

  6. The Deltopectoral Flap Revisited: The Internal Mammary Artery Perforator Flap.

    PubMed

    Ibrahim, Amir; Atiyeh, Bishara; Karami, Reem; Adelman, David M; Papazian, Nazareth J

    2016-03-01

    Pharyngo-esophageal and tracheostomal defects pose a challenge in head and neck reconstruction whenever microanastomosis is extremely difficult in hostile neck that is previously dissected and irradiated. The deltopectoral (DP) flap was initially described as a pedicled flap for such reconstruction with acceptable postoperative results. A major drawback is still that the DP flap is based on 3 perforator vessels leading to a decreased arc of rotation. The DP flap also left contour deformities in the donor site. The internal mammary artery perforator flap was described as a refinement of the deltopectoral flap. It is a pedicled fasciocutaneous flap based on a single perforator, with comparable and reliable blood supply compared with the DP flap, giving it the benefit of having a wide arc of rotation. It is both thin and pliable, with good skin color match and texture. The donor site can be closed primarily with no esthetic deformity and minimal morbidity. The procedure is relatively simple and does not require microvascular expertise. In this report, the authors describe a patient in whom bilateral internal mammary artery perforator flaps were used for subtotal pharyngo-esophageal reconstruction and neck resurfacing. The flaps healed uneventfully bilaterally with no postoperative complications. PMID:26854779

  7. Console video games, postural activity, and motion sickness during passive restraint.

    PubMed

    Chang, Chih-Hui; Pan, Wu-Wen; Chen, Fu-Chen; Stoffregen, Thomas A

    2013-08-01

    We examined the influence of passive restraint on postural activity and motion sickness in individuals who actively controlled a potentially nauseogenic visual motion stimulus (a driving video game). Twenty-four adults (20.09 ± 1.56 years; 167.80 ± 7.94 cm; 59.02 ± 9.18 kg) were recruited as participants. Using elastic bands, standing participants were passively restrained at the head, shoulders, hips, and knees. During restraint, participants played (i.e., controlled) a driving video game (a motorcycle race), for 50 min. During game play, we recorded the movement of the head and torso, using a magnetic tracking system. Following game play, participants answered a forced choice, yes/no question about whether they were motion sick, and were assigned to sick and well groups on this basis. In addition, before and after game play, participants completed the Simulator Sickness Questionnaire, which provided numerical ratings of the severity of individual symptoms. Five of 24 participants (20.83 %) reported motion sickness. Participants moved despite being passively restrained. Both the magnitude and the temporal dynamics of movement differed between the sick and well groups. The results show that passive restraint of the body can reduce motion sickness when the nauseogenic visual stimulus is under participants' active control and confirm that motion sickness is preceded by distinct patterns of postural activity even during passive restraint.

  8. Effects of attention and perceptual uncertainty on cerebellar activity during visual motion perception.

    PubMed

    Baumann, Oliver; Mattingley, Jason B

    2014-02-01

    Recent clinical and neuroimaging studies have revealed that the human cerebellum plays a role in visual motion perception, but the nature of its contribution to this function is not understood. Some reports suggest that the cerebellum might facilitate motion perception by aiding attentive tracking of visual objects. Others have identified a particular role for the cerebellum in discriminating motion signals in perceptually uncertain conditions. Here, we used functional magnetic resonance imaging to determine the degree to which cerebellar involvement in visual motion perception can be explained by a role in sustained attentive tracking of moving stimuli in contrast to a role in visual motion discrimination. While holding the visual displays constant, we manipulated attention by having participants attend covertly to a field of random-dot motion or a colored spot at fixation. Perceptual uncertainty was manipulated by varying the percentage of signal dots contained within the random-dot arrays. We found that attention to motion under high perceptual uncertainty was associated with strong activity in left cerebellar lobules VI and VII. By contrast, attending to motion under low perceptual uncertainty did not cause differential activation in the cerebellum. We found no evidence to support the suggestion that the cerebellum is involved in simple attentive tracking of salient moving objects. Instead, our results indicate that specific subregions of the cerebellum are involved in facilitating the detection and discrimination of task-relevant moving objects under conditions of high perceptual uncertainty. We conclude that the cerebellum aids motion perception under conditions of high perceptual demand. PMID:23982589

  9. The visual perception of natural motion: abnormal task-related neural activity in DYT1 dystonia.

    PubMed

    Sako, Wataru; Fujita, Koji; Vo, An; Rucker, Janet C; Rizzo, John-Ross; Niethammer, Martin; Carbon, Maren; Bressman, Susan B; Uluğ, Aziz M; Eidelberg, David

    2015-12-01

    Although primary dystonia is defined by its characteristic motor manifestations, non-motor signs and symptoms have increasingly been recognized in this disorder. Recent neuroimaging studies have related the motor features of primary dystonia to connectivity changes in cerebello-thalamo-cortical pathways. It is not known, however, whether the non-motor manifestations of the disorder are associated with similar circuit abnormalities. To explore this possibility, we used functional magnetic resonance imaging to study primary dystonia and healthy volunteer subjects while they performed a motion perception task in which elliptical target trajectories were visually tracked on a computer screen. Prior functional magnetic resonance imaging studies of healthy subjects performing this task have revealed selective activation of motor regions during the perception of 'natural' versus 'unnatural' motion (defined respectively as trajectories with kinematic properties that either comply with or violate the two-thirds power law of motion). Several regions with significant connectivity changes in primary dystonia were situated in proximity to normal motion perception pathways, suggesting that abnormalities of these circuits may also be present in this disorder. To determine whether activation responses to natural versus unnatural motion in primary dystonia differ from normal, we used functional magnetic resonance imaging to study 10 DYT1 dystonia and 10 healthy control subjects at rest and during the perception of 'natural' and 'unnatural' motion. Both groups exhibited significant activation changes across perceptual conditions in the cerebellum, pons, and subthalamic nucleus. The two groups differed, however, in their responses to 'natural' versus 'unnatural' motion in these regions. In healthy subjects, regional activation was greater during the perception of natural (versus unnatural) motion (P < 0.05). By contrast, in DYT1 dystonia subjects, activation was relatively greater

  10. The influence of yaw motion on the perception of active vs passive visual curvilinear displacement.

    PubMed

    Savona, Florian; Stratulat, Anca Melania; Roussarie, Vincent; Bourdin, Christophe

    2015-01-01

    Self-motion perception, which partly determines the realism of dynamic driving simulators, is based on multisensory integration. However, it remains unclear how the brain integrates these cues to create adequate motion perception, especially for curvilinear displacements. In the present study, the effect of visual, inertial and visuo-inertial cues (concordant or discordant bimodal cues) on self-motion perception was analyzed. Subjects were asked to evaluate (externally produced) or produce (self-controlled) curvilinear displacements as accurately as possible. The results show systematic overestimation of displacement, with better performance for active subjects than for passive ones. Furthermore, it was demonstrated that participants used unimodal or bimodal cues differently in performing their activity. When passive, subjects systematically integrated visual and inertial cues even when discordant, but with weightings that depended on the dynamics. On the contrary, active subjects were able to reject the inertial cue when the discordance became too high, producing self-motion perception on the basis of more reliable information. Thereby, multisensory integration seems to follow a non-linear integration model of, i.e., the cues' weight changes with the cue reliability and/or the intensity of the stimuli, as reported by previous studies. These results represent a basis for the adaptation of motion cueing algorithms are developed for dynamic driving simulators, by taking into account the dynamics of simulated motion in line with the status of the participants (driver or passenger).

  11. Point vortex model for prediction of sound generated by a wing with flap interacting with a passing vortex.

    PubMed

    Manela, A; Huang, L

    2013-04-01

    Acoustic signature of a rigid wing, equipped with a movable downstream flap and interacting with a line vortex, is studied in a two-dimensional low-Mach number flow. The flap is attached to the airfoil via a torsion spring, and the coupled fluid-structure interaction problem is analyzed using thin-airfoil methodology and application of the emended Brown and Michael equation. It is found that incident vortex passage above the airfoil excites flap motion at the system natural frequency, amplified above all other frequencies contained in the forcing vortex. Far-field radiation is analyzed using Powell-Howe analogy, yielding the leading order dipole-type signature of the system. It is shown that direct flap motion has a negligible effect on total sound radiation. The characteristic acoustic signature of the system is dominated by vortex sound, consisting of relatively strong leading and trailing edge interactions of the airfoil with the incident vortex, together with late-time wake sound resulting from induced flap motion. In comparison with the counterpart rigid (non-flapped) configuration, it is found that the flap may act as sound amplifier or absorber, depending on the value of flap-fluid natural frequency. The study complements existing analyses examining sound radiation in static- and detached-flap configurations. PMID:23556563

  12. Point vortex model for prediction of sound generated by a wing with flap interacting with a passing vortex.

    PubMed

    Manela, A; Huang, L

    2013-04-01

    Acoustic signature of a rigid wing, equipped with a movable downstream flap and interacting with a line vortex, is studied in a two-dimensional low-Mach number flow. The flap is attached to the airfoil via a torsion spring, and the coupled fluid-structure interaction problem is analyzed using thin-airfoil methodology and application of the emended Brown and Michael equation. It is found that incident vortex passage above the airfoil excites flap motion at the system natural frequency, amplified above all other frequencies contained in the forcing vortex. Far-field radiation is analyzed using Powell-Howe analogy, yielding the leading order dipole-type signature of the system. It is shown that direct flap motion has a negligible effect on total sound radiation. The characteristic acoustic signature of the system is dominated by vortex sound, consisting of relatively strong leading and trailing edge interactions of the airfoil with the incident vortex, together with late-time wake sound resulting from induced flap motion. In comparison with the counterpart rigid (non-flapped) configuration, it is found that the flap may act as sound amplifier or absorber, depending on the value of flap-fluid natural frequency. The study complements existing analyses examining sound radiation in static- and detached-flap configurations.

  13. Effects of eating on vection-induced motion sickness, cardiac vagal tone, and gastric myoelectric activity

    NASA Technical Reports Server (NTRS)

    Uijtdehaage, S. H.; Stern, R. M.; Koch, K. L.

    1992-01-01

    This study investigated the effect of food ingestion on motion sickness severity and its physiological mechanisms. Forty-six fasted subjects were assigned either to a meal group or to a no-meal group. Electrogastrographic (EGG) indices (normal 3 cpm activity and abnormal 4-9 cpm tachyarrhythmia) and respiratory sinus arrhythmia (RSA) were measured before and after a meal and during a subsequent exposure to a rotating drum in which illusory self-motion was induced. The results indicated that food intake enhanced cardiac parasympathetic tone (RSA) and increased gastric 3 cpm activity. Postprandial effects on motion sickness severity remain equivocal due to group differences in RSA baseline levels. During drum rotation, dysrhythmic activity of the stomach (tachyarrhythmia) and vagal withdrawal were observed. Furthermore, high levels of vagal tone prior to drum rotation predicted a low incidence of motion sickness symptoms, and were associated positively with gastric 3 cpm activity and negatively with tachyarrhythmia. These data suggest that enhanced levels of parasympathetic activity can alleviate motion sickness symptoms by suppressing, in part, its dysrhythmic gastric underpinnings.

  14. Embodied Semiotic Activities and Their Role in the Construction of Mathematical Meaning of Motion Graphs

    ERIC Educational Resources Information Center

    Botzer, Galit; Yerushalmy, Michal

    2008-01-01

    This paper examines the relation between bodily actions, artifact-mediated activities, and semiotic processes that students experience while producing and interpreting graphs of two-dimensional motion in the plane. We designed a technology-based setting that enabled students to engage in embodied semiotic activities and experience two modes of…

  15. Your Students Can Be Rocket Scientists! A Galaxy of Great Activities about Astronauts, Gravity, and Motion.

    ERIC Educational Resources Information Center

    Kepler, Lynne

    1994-01-01

    Presents activities for a springtime Space Day that can teach students about astronauts, gravity, and motion. Activities include creating a paper bag spacecraft to study liftoff and having students simulate gravity's effects by walking in various manners and recording pulse rates. A list of resources is included. (SM)

  16. Morphometrical investigations on the reproductive activity of the ovaries in rats subjected to immobilization and to motion activity

    NASA Technical Reports Server (NTRS)

    Konstantinov, N.; Cheresharov, L.; Toshkova, S.

    1982-01-01

    Wistar-strain white female rats were divided into three groups, with the first group subjected to motion loading, the second used as control, and the third group was immobilized. A considerable reduction in numbers of corpora lutea was observed in the immobilized group, together with smaller numbers of embryos, high percent of embryo mortality, fetal growth retardation, and endometrium disorders. The control group showed no deviation from normal conditions, and there was slight improvement in reproductive activity of animals under motion loading.

  17. Experimental study of flapping jets in a soap film

    NASA Astrophysics Data System (ADS)

    Lee, Julia; Kim, Ildoo; Mandre, Shreyas

    2015-11-01

    Plateau and Rayleigh's observation and explanation on jet instability have inspired us over the years and there has been a significant advance in understanding the jet dynamics. Here, we present a quasi-two-dimensional experimental study of flapping jets in a soap film. Newtonian and non-Newtonian solutions are injected in a flowing soap film. Thinning, break-ups, and beads-on-a-string of the jets, and axisymmetric vortices shredded from the flapping jets are visualized. We employ PIV of the flow motion around the jets to gain an understanding of the roles of instabilities in the flow.

  18. Skin flaps and grafts - self-care

    MedlinePlus

    ... Free flap - self-care; Skin autografting - self-care; Pressure ulcer skin flap self-care; Burns skin flap self- ... skin infection Surgery for skin cancer Venous ulcers , pressure ulcers , or diabetic ulcers that DO NOT heal After ...

  19. Multimodal integration of self-motion cues in the vestibular system: active versus passive translations.

    PubMed

    Carriot, Jerome; Brooks, Jessica X; Cullen, Kathleen E

    2013-12-11

    The ability to keep track of where we are going as we navigate through our environment requires knowledge of our ongoing location and orientation. In response to passively applied motion, the otolith organs of the vestibular system encode changes in the velocity and direction of linear self-motion (i.e., heading). When self-motion is voluntarily generated, proprioceptive and motor efference copy information is also available to contribute to the brain's internal representation of current heading direction and speed. However to date, how the brain integrates these extra-vestibular cues with otolith signals during active linear self-motion remains unknown. Here, to address this question, we compared the responses of macaque vestibular neurons during active and passive translations. Single-unit recordings were made from a subgroup of neurons at the first central stage of sensory processing in the vestibular pathways involved in postural control and the computation of self-motion perception. Neurons responded far less robustly to otolith stimulation during self-generated than passive head translations. Yet, the mechanism underlying the marked cancellation of otolith signals did not affect other characteristics of neuronal responses (i.e., baseline firing rate, tuning ratio, orientation of maximal sensitivity vector). Transiently applied perturbations during active motion further established that an otolith cancellation signal was only gated in conditions where proprioceptive sensory feedback matched the motor-based expectation. Together our results have important implications for understanding the brain's ability to ensure accurate postural and motor control, as well as perceptual stability, during active self-motion.

  20. Spontaneous Motion in Hierarchically Assembled Active Cellular Materials

    NASA Astrophysics Data System (ADS)

    Chen, Daniel

    2013-03-01

    With exquisite precision and reproducibility, cells orchestrate the cooperative action of thousands of nanometer-sized molecular motors to carry out mechanical tasks at much larger length scales, such as cell motility, division and replication. Besides their biological importance, such inherently far-from-equilibrium processes are an inspiration for the development of soft materials with highly sought after biomimetic properties such as autonomous motility and self-healing. I will describe our exploration of such a class of biologically inspired soft active materials. Starting from extensile bundles comprised of microtubules and kinesin, we hierarchically assemble active analogs of polymeric gels, liquid crystals and emulsions. At high enough concentration, microtubule bundles form an active gel network capable of generating internally driven chaotic flows that enhance transport and fluid mixing. When confined to emulsion droplets, these 3D networks buckle onto the water-oil interface forming a dense thin film of bundles exhibiting cascades of collective buckling, fracture, and self-healing driven by internally generated stresses from the kinesin clusters. When compressed against surfaces, this active nematic cortex exerts traction stresses that propel the locomotion of the droplet. Taken together, these observations exemplify how assemblies of animate microscopic objects exhibit collective biomimetic properties that are fundamentally distinct from those found in materials assembled from inanimate building blocks. These assemblies, in turn, enable the generation of a new class of materials that exhibit macroscale flow phenomena emerging from nanoscale components.

  1. Flexible Flapping Foils

    NASA Astrophysics Data System (ADS)

    Marais, Catherine; Godoy-Diana, Ramiro; Wesfreid, José. Eduardo

    2010-11-01

    Hydrodynamic tunnel experiments with flexible flapping foils of 4:1 span-to-chord aspect ratio are used in the present work to study the effect of foil compliance in the dynamical features of a propulsive wake. The average thrust force produced by the foil is estimated from 2D PIV measurements and the regime transitions in the wake are characterized according to a flapping frequency-amplitude phase diagram as in Godoy-Diana et al. (Phys. Rev. E 77, 016308, 2008). We show that the thrust production regime occurs on a broader region of the parameter space for flexible foils, with propulsive forces up to 3 times greater than for the rigid case. We examine in detail the vortex generation at the trailing edge of the foils, and propose a mechanism to explain how foil deformation leads to an optimization of propulsion.

  2. Engineered Vascularized Muscle Flap.

    PubMed

    Egozi, Dana; Shandalov, Yulia; Freiman, Alina; Rosenfeld, Dekel; Ben-Shimol, David; Levenberg, Shulamit

    2016-01-01

    One of the main factors limiting the thickness of a tissue construct and its consequential viability and applicability in vivo, is the control of oxygen supply to the cell microenvironment, as passive diffusion is limited to a very thin layer. Although various materials have been described to restore the integrity of full-thickness defects of the abdominal wall, no material has yet proved to be optimal, due to low graft vascularization, tissue rejection, infection, or inadequate mechanical properties. This protocol describes a means of engineering a fully vascularized flap, with a thickness relevant for muscle tissue reconstruction. Cell-embedded poly L-lactic acid/poly lactic-co-glycolic acid constructs are implanted around the mouse femoral artery and vein and maintained in vivo for a period of one or two weeks. The vascularized graft is then transferred as a flap towards a full thickness defect made in the abdomen. This technique replaces the need for autologous tissue sacrifications and may enable the use of in vitro engineered vascularized flaps in many surgical applications. PMID:26779840

  3. The Versatile Modiolus Perforator Flap

    PubMed Central

    Gunnarsson, Gudjon Leifur; Thomsen, Jorn Bo

    2016-01-01

    Background: Perforator flaps are well established, and their usefulness as freestyle island flaps is recognized. The whereabouts of vascular perforators and classification of perforator flaps in the face are a debated subject, despite several anatomical studies showing similar consistency. In our experience using freestyle facial perforator flaps, we have located areas where perforators are consistently found. This study is focused on a particular perforator lateral to the angle of the mouth; the modiolus and the versatile modiolus perforator flap. Methods: A cohort case series of 14 modiolus perforator flap reconstructions in 14 patients and a color Doppler ultrasonography localization of the modiolus perforator in 10 volunteers. Results: All 14 flaps were successfully used to reconstruct the defects involved, and the location of the perforator was at the level of the modiolus as predicted. The color Doppler ultrasonography study detected a sizeable perforator at the level of the modiolus lateral to the angle of the mouth within a radius of 1 cm. This confirms the anatomical findings of previous authors and indicates that the modiolus perforator is a consistent anatomical finding, and flaps based on it can be recommended for several indications from the reconstruction of defects in the perioral area, cheek and nose. Conclusions: The modiolus is a well-described anatomical area containing a sizeable perforator that is consistently present and readily visualized using color Doppler ultrasonography. We have used the modiolus perforator flap successfully for several indications, and it is our first choice for perioral reconstruction. PMID:27257591

  4. Flag flapping in a channel

    NASA Astrophysics Data System (ADS)

    Alben, Silas; Shoele, Kourosh; Mittal, Rajat; Jha, Sourabh; Glezer, Ari

    2015-11-01

    We study the flapping of a flag in an inviscid channel flow. We focus especially on how quantities vary with channel spacing. As the channel walls move inwards towards the flag, heavier flags become more unstable, while light flags' stability is less affected. We use a vortex sheet model to compute large-amplitude flapping, and find that the flag undergoes a series of jumps to higher flapping modes as the channel walls are moved towards the flag. Meanwhile, the drag on the flag and the energy lost to the wake first rise as the walls become closer, then drop sharply as the flag moves to a higher flapping mode.

  5. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow

    PubMed Central

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity. PMID:27597999

  6. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow.

    PubMed

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity. PMID:27597999

  7. Activation of the Human MT Complex by Motion in Depth Induced by a Moving Cast Shadow.

    PubMed

    Katsuyama, Narumi; Usui, Nobuo; Taira, Masato

    2016-01-01

    A moving cast shadow is a powerful monocular depth cue for motion perception in depth. For example, when a cast shadow moves away from or toward an object in a two-dimensional plane, the object appears to move toward or away from the observer in depth, respectively, whereas the size and position of the object are constant. Although the cortical mechanisms underlying motion perception in depth by cast shadow are unknown, the human MT complex (hMT+) is likely involved in the process, as it is sensitive to motion in depth represented by binocular depth cues. In the present study, we examined this possibility by using a functional magnetic resonance imaging (fMRI) technique. First, we identified the cortical regions sensitive to the motion of a square in depth represented via binocular disparity. Consistent with previous studies, we observed significant activation in the bilateral hMT+, and defined functional regions of interest (ROIs) there. We then investigated the activity of the ROIs during observation of the following stimuli: 1) a central square that appeared to move back and forth via a moving cast shadow (mCS); 2) a segmented and scrambled cast shadow presented beside the square (sCS); and 3) no cast shadow (nCS). Participants perceived motion of the square in depth in the mCS condition only. The activity of the hMT+ was significantly higher in the mCS compared with the sCS and nCS conditions. Moreover, the hMT+ was activated equally in both hemispheres in the mCS condition, despite presentation of the cast shadow in the bottom-right quadrant of the stimulus. Perception of the square moving in depth across visual hemifields may be reflected in the bilateral activation of the hMT+. We concluded that the hMT+ is involved in motion perception in depth induced by moving cast shadow and by binocular disparity.

  8. MAGNETIC HELICITY TRANSPORTED BY FLUX EMERGENCE AND SHUFFLING MOTIONS IN SOLAR ACTIVE REGION NOAA 10930

    SciTech Connect

    Zhang, Y.; Kitai, R.; Takizawa, K. E-mail: zhangyin@bao.ac.cn

    2012-06-01

    We present a new methodology which can determine magnetic helicity transport by the passage of helical magnetic field lines from the sub-photosphere and the shuffling motions of footpoints of preexisting coronal field lines separately. It is well known that only the velocity component, which is perpendicular to the magnetic field ({upsilon}{sub B}), has contributed to the helicity accumulation. Here, we demonstrate that {upsilon}{sub B} can be deduced from a horizontal motion and vector magnetograms under a simple relation of {upsilon}{sub t} = {mu}{sub t} + ({upsilon}{sub n}/B{sub n} ) B{sub t}, as suggested by Demoulin and Berger. Then after dividing {upsilon}{sub B} into two components, as one is tangential and the other is normal to the solar surface, we can determine both terms of helicity transport. Active region (AR) NOAA 10930 is analyzed as an example during its solar disk center passage by using data obtained by the Spectropolarimeter and the Narrowband Filter Imager of Solar Optical Telescope on board Hinode. We find that in our calculation the helicity injection by flux emergence and shuffling motions have the same sign. During the period we studied, the main contribution of helicity accumulation comes from the flux emergence effect, while the dynamic transient evolution comes from the shuffling motions effect. Our observational results further indicate that for this AR the apparent rotational motion in the following sunspot is the real shuffling motions on the solar surface.

  9. Spontaneous chiral symmetry breaking in collective active motion

    NASA Astrophysics Data System (ADS)

    Breier, Rebekka E.; Selinger, Robin L. B.; Ciccotti, Giovanni; Herminghaus, Stephan; Mazza, Marco G.

    2016-02-01

    Chiral symmetry breaking is ubiquitous in biological systems, from DNA to bacterial suspensions. A key unresolved problem is how chiral structures may spontaneously emerge from achiral interactions. We study a simple model of active swimmers in three dimensions that effectively incorporates hydrodynamic interactions. We perform large-scale molecular dynamics simulations (up to 106 particles) and find long-lived metastable collective states that exhibit chiral organization although the interactions are achiral. We elucidate under which conditions these chiral states will emerge and grow to large scales. To explore the complex phase space available to the system, we perform nonequilibrium quenches on a one-dimensional Lebwohl-Lasher model with periodic boundary conditions to study the likelihood of formation of chiral structures.

  10. Flapping dynamics of a flexible propulsor near ground

    NASA Astrophysics Data System (ADS)

    Ryu, Jaeha; Park, Sung Goon; Kim, Boyoung; Sung, Hyung Jin

    2016-06-01

    The flapping motion of a flexible propulsor near the ground was simulated using the immersed boundary method. The hydrodynamic benefits of the propulsor near the ground were explored by varying the heaving frequency (St) of the leading edge of the flexible propulsor. Propulsion near the ground had some advantages in generating thrust and propelling faster than propulsion away from the ground. The mode analysis and flapping amplitude along the Lagrangian coordinate were examined to analyze the kinematics as a function of the ground proximity (d) and St. The trailing edge amplitude (a_tail ) and the net thrust (overline{{F}}_x ) were influenced by St of the flexible propulsor. The vortical structures in the wake were analyzed for different flapping conditions.

  11. Method and apparatus for controlling pitch and flap angles of a wind turbine

    DOEpatents

    Deering, Kenneth J.; Wohlwend, Keith P.

    2009-05-12

    A wind turbine with improved response to wind conditions is provided. Blade flap angle motion is accompanied by a change in pitch angle by an amount defining a pitch/flap coupling ratio. The coupling ratio is non-constant as a function of a flap angle and is preferably a substantially continuous, non-linear function of flap angle. The non-constant coupling ratio can be provided by mechanical systems such as a series of linkages or by configuring electronic or other control systems and/or angle sensors. A link with a movable proximal end advantageously is part of the mechanical system. The system can provide relatively large coupling ratios and relatively large rates of coupling ratio changes especially for near-feather pitches and low flap angles.

  12. Numerical simulation and reduced-order modeling of a flapping airfoil

    NASA Astrophysics Data System (ADS)

    Lewin, Gregory Carl

    identical. The importance of viscous effects for low Reynolds number flapping flight is discussed. The computational model is used as the basis for developing a reduced-order model for active control of a flapping wing. Using proper orthogonal decomposition (POD), sets of orthogonal basis functions are generated for simulating flows at various heaving and pitching parameters. With POD, most of the energy in the flow is concentrated in just a few basis functions. These functions are used for the projection of the Navier-Stokes equations using a Galerkin projection, reducing them to a small set of coupled, non-linear ordinary differential equations. The Galerkin projection is used to simulate oscillatory motions that are both similar to, and different from, the motion used to generate the POD modes; however; errors are introduced into the model from several sources. The focus of the current work is on the causes and effects of errors in the model on important aspects of the flow, chiefly input and output power and efficiency. The suitability of this approach for controlling a flapping wing over a broad range of parameters is discussed.

  13. Reduction of Flap Side Edge Noise - the Blowing Flap

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Brooks, THomas F.

    2005-01-01

    A technique to reduce the noise radiating from a wing-flap side edge is being developed. As an airplane wing with an extended flap is exposed to a subsonic airflow, air is blown outward through thin rectangular chord-wise slots at various locations along the side edges and side surface of the flap to weaken and push away the vortices that originate in that region of the flap and are responsible for important noise emissions. Air is blown through the slots at up to twice the local flow velocity. The blowing is done using one or multiple slots, where a slot is located along the top, bottom or side surface of the flap along the side edge, or also along the intersection of the bottom (or top) and side surfaces.

  14. Image-based synchronization of force and bead motion in active electromagnetic microrheometry

    NASA Astrophysics Data System (ADS)

    Park, Chang-Young; Saleh, Omar A.

    2014-12-01

    In the past, electromagnetic tweezers have been used to make active microrheometers. An active microrheometer measures the dynamic mechanical properties of a material from the motion of embedded particles under external force, e.g. a sinusoidal magnetic force generated by a sinusoidal current on a coil. The oscillating amplitude and the phase lag of the motion are then used to estimate the material’s dynamic mechanical properties. The phase lag, in particular, requires precise synchronization of the particle motion with the external force. In previous works, synchronization difficulties have arisen from measuring two parameters with two instruments, one of them being a camera. We solved the synchronization issue by measuring two parameters with a single instrument, the camera alone. From captured images, particles can be tracked in three dimensions through an image-analysis algorithm while the current on the coil can be measured from the brightness of the image; this enables simultaneous synchronization of the phases of the driving current on the electromagnet coil and the motion of the magnetic probe particle. We calibrate the phase delay between the magnetic force and the particle’s motion in glycerol and confirm the calibration with a Hall probe. The technique is further tested by measuring the shear modulus of a polyacrylamide gel, and comparing the results to those obtained using a conventional rheometer.

  15. Active linear head motion improves dynamic visual acuity in pursuing a high-speed moving object.

    PubMed

    Hasegawa, Tatsuhisa; Yamashita, Masayuki; Suzuki, Toshihiro; Hisa, Yasuo; Wada, Yoshiro

    2009-04-01

    We usually move both our eyes and our head when pursuing a high-speed moving object. However, the vestibulo-ocular reflex (VOR), evoked by head motion, seems to disturb smooth pursuit eye movement because the VOR stabilizes the gaze against head motion. To determine whether head motion is advantageous for pursuing a high-speed moving object, we examined dynamic visual acuity (DVA) for a high-speed (80 degrees /s) rightward moving object with and without active linear rightward head motion (HM) at a maximum of 50 cm/s in nine healthy subjects. Furthermore, we analyzed eye and head movements to investigate the contribution of linear VOR (LVOR) and smooth eye movement under these conditions. In most subjects, active linear head motion improved DVA for a high-speed moving object. Subjects with higher DVA scores under HM had robust rightward gaze (eye + head) velocities (>60 cm/s), i.e., rightward smooth eye movements (>10 degrees /s). With the head stationary (HS), faster smooth eye movements (>40 degrees /s) were generated when the subjects pursued a high-speed moving object. They also showed anticipatory smooth eye movements under conditions HM and HS. However, the level of suppression of their LVOR abilities was equal to that of the others. These results suggest that the ability to generate anticipatory smooth pursuit eye movements for following a high-speed moving object against the LVOR is a determining factor for improvement of DVA under HM.

  16. Prospective active marker motion correction improves statistical power in BOLD fMRI.

    PubMed

    Muraskin, Jordan; Ooi, Melvyn B; Goldman, Robin I; Krueger, Sascha; Thomas, William J; Sajda, Paul; Brown, Truman R

    2013-03-01

    Group level statistical maps of blood oxygenation level dependent (BOLD) signals acquired using functional magnetic resonance imaging (fMRI) have become a basic measurement for much of systems, cognitive and social neuroscience. A challenge in making inferences from these statistical maps is the noise and potential confounds that arise from the head motion that occurs within and between acquisition volumes. This motion results in the scan plane being misaligned during acquisition, ultimately leading to reduced statistical power when maps are constructed at the group level. In most cases, an attempt is made to correct for this motion through the use of retrospective analysis methods. In this paper, we use a prospective active marker motion correction (PRAMMO) system that uses radio frequency markers for real-time tracking of motion, enabling on-line slice plane correction. We show that the statistical power of the activation maps is substantially increased using PRAMMO compared to conventional retrospective correction. Analysis of our results indicates that the PRAMMO acquisition reduces the variance without decreasing the signal component of the BOLD (beta). Using PRAMMO could thus improve the overall statistical power of fMRI based BOLD measurements, leading to stronger inferences of the nature of processing in the human brain.

  17. Evidence of left-lateral active motion at the North America-Caribbean plate boundary

    NASA Astrophysics Data System (ADS)

    Leroy, S. D.; Ellouz, N.; Corbeau, J.; Rolandone, F.; Mercier De Lepinay, B. F.; Meyer, B.; Momplaisir, R.; Granja, J. L.; Battani, A.; Burov, E. B.; Clouard, V.; Deschamps, R.; Gorini, C.; Hamon, Y.; LE Pourhiet, L.; Loget, N.; Lucazeau, F.; Pillot, D.; Poort, J.; Tankoo, K.; Cuevas, J. L.; Alcaide, J.; Poix, C. J.; Mitton, S.; Rodriguez, Y.; Schmitz, J.; Munoz Martin, A.

    2014-12-01

    The North America-Caribbean plate boundary is one of the least-known among large plate boundaries. Although it was identified early on as an example of a strike-slip fault in the north of Hispaniola, its structure and rate of motion remains poorly constrained. We present the first direct evidence for active sinistral strike-slip motion along this fault, based on swath seafloor mapping of the northern Haiti area. There is evidence for ~16.5 km of apparent strike-slip motion along the mapped segment of the Septentrional fault zone off Cap Haitien town which is terminated to the east onland Dominican republic and in the west to southern Cuban margin. By evaluating these new constraints within the context of geodetic models of global plate motions, we estimate an activity of the fault since 2 Ma with an angular velocity for the Caribbean plate relative to the North America predicted 6-12 mmyr-1 sinistral motion along the Septentrional fault zone. This transform fault was initiated around 20 million years ago in its western segment and since 2 Ma in its eastern segment in response to a regional reorganization of plate velocities and directions, which induced a change in configuration of plate boundaries.

  18. Thermostable flap endonuclease from the archaeon, Pyrococcus horikoshii, cleaves the replication fork-like structure endo/exonucleolytically.

    PubMed

    Matsui, E; Kawasaki, S; Ishida, H; Ishikawa, K; Kosugi, Y; Kikuchi, H; Kawarabayashi, Y; Matsui, I

    1999-06-25

    The flap endonuclease gene homologue from the hyperthermophilic archaeon, Pyrococcus horikoshii, was overexpressed in Escherichia coli and purified. The results of gel filtration indicated that this protein was a 41-kDa monomer. P. horikoshii flap endonuclease (phFEN) cleaves replication fork-like substrates (RF) and 5' double-strand flap structures (DF) using both flap endonuclease and 5'-3'-exonuclease activities. The mammalian flap endonuclease (mFEN) is a single-strand flap-specific endonuclease (Harrington, J. J., and Lieber, M. R. (1994) EMBO J. 13, 1235-1246), but the action patterns of phFEN appear to be quite different from those of mFEN at this point. The DF-specific flap endonuclease and 5'-exonuclease activities have not yet been reported. Therefore, this is the first report of the specific endo/exonuclease activities of phFEN. The DF-specific 5'-exonuclease activity degraded the downstream primer of 3' single-flap structure and was 15 times higher than the activities against nicked substrates without 3' flap strand. DF-specific flap endonuclease cleaved the 5' double-flap strand in DF and the lagging strand in RF at the junction portion. Because the RF appears to be the intermediate structure, due to the arrest of the replication fork, the double strand breaks after the arrests of the replication forks are probably caused by phFEN.

  19. Complex Human Activity Recognition Using Smartphone and Wrist-Worn Motion Sensors.

    PubMed

    Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J M

    2016-03-24

    The position of on-body motion sensors plays an important role in human activity recognition. Most often, mobile phone sensors at the trouser pocket or an equivalent position are used for this purpose. However, this position is not suitable for recognizing activities that involve hand gestures, such as smoking, eating, drinking coffee and giving a talk. To recognize such activities, wrist-worn motion sensors are used. However, these two positions are mainly used in isolation. To use richer context information, we evaluate three motion sensors (accelerometer, gyroscope and linear acceleration sensor) at both wrist and pocket positions. Using three classifiers, we show that the combination of these two positions outperforms the wrist position alone, mainly at smaller segmentation windows. Another problem is that less-repetitive activities, such as smoking, eating, giving a talk and drinking coffee, cannot be recognized easily at smaller segmentation windows unlike repetitive activities, like walking, jogging and biking. For this purpose, we evaluate the effect of seven window sizes (2-30 s) on thirteen activities and show how increasing window size affects these various activities in different ways. We also propose various optimizations to further improve the recognition of these activities. For reproducibility, we make our dataset publicly available.

  20. Complex Human Activity Recognition Using Smartphone and Wrist-Worn Motion Sensors.

    PubMed

    Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J M

    2016-01-01

    The position of on-body motion sensors plays an important role in human activity recognition. Most often, mobile phone sensors at the trouser pocket or an equivalent position are used for this purpose. However, this position is not suitable for recognizing activities that involve hand gestures, such as smoking, eating, drinking coffee and giving a talk. To recognize such activities, wrist-worn motion sensors are used. However, these two positions are mainly used in isolation. To use richer context information, we evaluate three motion sensors (accelerometer, gyroscope and linear acceleration sensor) at both wrist and pocket positions. Using three classifiers, we show that the combination of these two positions outperforms the wrist position alone, mainly at smaller segmentation windows. Another problem is that less-repetitive activities, such as smoking, eating, giving a talk and drinking coffee, cannot be recognized easily at smaller segmentation windows unlike repetitive activities, like walking, jogging and biking. For this purpose, we evaluate the effect of seven window sizes (2-30 s) on thirteen activities and show how increasing window size affects these various activities in different ways. We also propose various optimizations to further improve the recognition of these activities. For reproducibility, we make our dataset publicly available. PMID:27023543

  1. Complex Human Activity Recognition Using Smartphone and Wrist-Worn Motion Sensors

    PubMed Central

    Shoaib, Muhammad; Bosch, Stephan; Incel, Ozlem Durmaz; Scholten, Hans; Havinga, Paul J. M.

    2016-01-01

    The position of on-body motion sensors plays an important role in human activity recognition. Most often, mobile phone sensors at the trouser pocket or an equivalent position are used for this purpose. However, this position is not suitable for recognizing activities that involve hand gestures, such as smoking, eating, drinking coffee and giving a talk. To recognize such activities, wrist-worn motion sensors are used. However, these two positions are mainly used in isolation. To use richer context information, we evaluate three motion sensors (accelerometer, gyroscope and linear acceleration sensor) at both wrist and pocket positions. Using three classifiers, we show that the combination of these two positions outperforms the wrist position alone, mainly at smaller segmentation windows. Another problem is that less-repetitive activities, such as smoking, eating, giving a talk and drinking coffee, cannot be recognized easily at smaller segmentation windows unlike repetitive activities, like walking, jogging and biking. For this purpose, we evaluate the effect of seven window sizes (2–30 s) on thirteen activities and show how increasing window size affects these various activities in different ways. We also propose various optimizations to further improve the recognition of these activities. For reproducibility, we make our dataset publicly available. PMID:27023543

  2. Flap-Edge Blowing Experiments

    NASA Technical Reports Server (NTRS)

    Gaeta, R. J.; Englar, R. J.; Ahuja, K. K.

    2003-01-01

    This Appendix documents the salient results from an effort to mitigate the so-called flap-edge noise generated at the split between a flap edge that is deployed and the undeployed flap. Utilizing a Coanda surface installed at the flap edge, steady blowing was used in an attempt to diminish the vortex strength resulting from the uneven lift distribution. The strength of this lifting vortex was augmented by steady blowing over the deployed flap. The test article for this study was the same 2D airfoil used in the steady blowing program reported earlier (also used in pulsed blowing tests, see Appendix G), however its trailing edge geometry was modified. An exact duplicate of the airfoil shape was made out of fiberglass with no flap, and in the clean configuration. It was attached to the existing airfoil to make an airfoil that has half of its flap deployed and half un-deployed. Figure 1 shows a schematic of the planform showing the two areas where steady blowing was introduced. The flap-edge blowing or the auxiliary blowing was in the direction normal to the freestream velocity vector. Slot heights for the blowing chambers were on the order of 0.0 14 inches.

  3. Perturbation solutions for the influence of forward flight on helicopter rotor flapping stability

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1974-01-01

    The stability of the flapping motion of a helicopter rotor blade in forward flight is investigated, using a perturbation technique which gives analytic expressions for the eigenvalues, including the influence of the periodic aerodynamic forces in forward flight. The perturbation solutions are based on small advance ratio (the ratio of the helicopter forward speed to the rotor tip speed). The rotor configurations considered are a single, independent blade; a teetering rotor; a gimballed rotor with three, four, and five or more blades; and a rotor with N independent blades. The constant coefficient approximation with the equations and degrees of freedom in the nonrotating frame represents the flap dynamic reasonably well for the lower frequency modes, although it cannot, of course, be completely correct. The transfer function of the rotor flap response to sinusoidal pitch input is examined, as an alternative to the eigenvalues as a representation of the dynamic characteristics of the flap motion.

  4. An aeroelastic analysis of a flexible flapping wing using modified strip theory

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Kwan; Lee, Jun-Seong; Lee, Jin-Young; Han, Jae-Hung

    2008-03-01

    The present study proposed a coupling method for the fluid-structural interaction analysis of a flexible flapping wing. An efficient numerical aerodynamic model was suggested, which was based on the modified strip theory and further improved to take into account a high relative angle of attack and dynamic stall effects induced by pitching and plunging motions. The aerodynamic model was verified with experimental data of rigid wings. A reduced structural model of a rectangular flapping wing was also established by using flexible multibody dynamics and a modal approach technique, so as to consider large flapping motions and local elastic deformations. Then, the aeroelastic analysis method was developed by coupling these aerodynamic and structural modules. To measure the aerodynamic forces of the rectangular flapping wing, static and dynamic tests were performed in a low speed wind-tunnel for various flapping pitch angles, flapping frequencies and the airspeeds. Finally, the aerodynamic forces predicted by the aeroelastic analysis method showed good agreement with the experimental data of the rectangular flapping wing.

  5. Pathological tremor and voluntary motion modeling and online estimation for active compensation.

    PubMed

    Bo, Antônio Padilha Lanari; Poignet, Philippe; Geny, Christian

    2011-04-01

    This paper presents an algorithm to perform online tremor characterization from motion sensors measurements, while filtering the voluntary motion performed by the patient. In order to estimate simultaneously both nonstationary signals in a stochastic filtering framework, pathological tremor was represented by a time-varying harmonic model and voluntary motion was modeled as an auto-regressive moving-average (ARMA) model. Since it is a nonlinear problem, an extended Kalman filter (EKF) was used. The developed solution was evaluated with simulated signals and experimental data from patients with different pathologies. Also, the results were comprehensively compared with alternative techniques proposed in the literature, evidencing the better performance of the proposed method. The algorithm presented in this paper may be an important tool in the design of active tremor compensation systems.

  6. Active faults, stress field and plate motion along the Indo-Eurasian plate boundary

    NASA Astrophysics Data System (ADS)

    Nakata, Takashi; Otsuki, Kenshiro; Khan, S. H.

    1990-09-01

    The active faults of the Himalayas and neighboring areas are direct indicators of Recent and sub-Recent crustal movements due to continental collision between the Indian and Eurasian plates. The direction of the maximum horizontal shortening or horizontal compressive stress axes deduced from the strike and type of active faulting reveals a characteristic regional stress field along the colliding boundary. The trajectories of the stress axes along the transcurrent faults and the Eastern Himalayan Front, are approximately N-S, parallel to the relative motion of the two plates. However, along the southern margin of the Eurasian plate, they are NE-SW in the Western Himalayan Front and NW-SE to E-W in the Kirthar-Sulaiman Front, which is not consistent with the direction of relative plate motion. A simple model is proposed in order to explain the regional stress pattern. In this model, the tectonic sliver between the transcurrent faults and the plate margin, is dragged northward by the oblique convergence of the Indian plate. Thus, the direction of relative motion between the tectonic sliver and the Indian plate changes regionally, causing local compressive stress fields. Judging from the long-term slip rates along the active faults, the relative motion between the Indian and Eurasian plates absorbed in the colliding zone is about one fourth of its total amount; the rest may be consumed along the extensive strike-slip faults in Tibet and China.

  7. Population activity in the human dorsal pathway predicts the accuracy of visual motion detection.

    PubMed

    Donner, Tobias H; Siegel, Markus; Oostenveld, Robert; Fries, Pascal; Bauer, Markus; Engel, Andreas K

    2007-07-01

    A person's ability to detect a weak visual target stimulus varies from one viewing to the next. We tested whether the trial-to-trial fluctuations of neural population activity in the human brain are related to the fluctuations of behavioral performance in a "yes-no" visual motion-detection task. We recorded neural population activity with whole head magnetoencephalography (MEG) while subjects searched for a weak coherent motion signal embedded in spatiotemporal noise. We found that, during motion viewing, MEG activity in the 12- to 24-Hz ("beta") frequency range is higher, on average, before correct behavioral choices than before errors and that it predicts correct choices on a trial-by-trial basis. This performance-predictive activity is not evident in the prestimulus baseline and builds up slowly after stimulus onset. Source reconstruction revealed that the performance-predictive activity is expressed in the posterior parietal and dorsolateral prefrontal cortices and, less strongly, in the visual motion-sensitive area MT+. The 12- to 24-Hz activity in these key stages of the human dorsal visual pathway is correlated with behavioral choice in both target-present and target-absent conditions. Importantly, in the absence of the target, 12- to 24-Hz activity tends to be higher before "no" choices ("correct rejects") than before "yes" choices ("false alarms"). It thus predicts the accuracy, and not the content, of subjects' upcoming perceptual reports. We conclude that beta band activity in the human dorsal visual pathway indexes, and potentially controls, the efficiency of neural computations underlying simple perceptual decisions.

  8. Active contour-based visual tracking by integrating colors, shapes, and motions.

    PubMed

    Hu, Weiming; Zhou, Xue; Li, Wei; Luo, Wenhan; Zhang, Xiaoqin; Maybank, Stephen

    2013-05-01

    In this paper, we present a framework for active contour-based visual tracking using level sets. The main components of our framework include contour-based tracking initialization, color-based contour evolution, adaptive shape-based contour evolution for non-periodic motions, dynamic shape-based contour evolution for periodic motions, and the handling of abrupt motions. For the initialization of contour-based tracking, we develop an optical flow-based algorithm for automatically initializing contours at the first frame. For the color-based contour evolution, Markov random field theory is used to measure correlations between values of neighboring pixels for posterior probability estimation. For adaptive shape-based contour evolution, the global shape information and the local color information are combined to hierarchically evolve the contour, and a flexible shape updating model is constructed. For the dynamic shape-based contour evolution, a shape mode transition matrix is learnt to characterize the temporal correlations of object shapes. For the handling of abrupt motions, particle swarm optimization is adopted to capture the global motion which is applied to the contour in the current frame to produce an initial contour in the next frame.

  9. Active contour-based visual tracking by integrating colors, shapes, and motions.

    PubMed

    Hu, Weiming; Zhou, Xue; Li, Wei; Luo, Wenhan; Zhang, Xiaoqin; Maybank, Stephen

    2013-05-01

    In this paper, we present a framework for active contour-based visual tracking using level sets. The main components of our framework include contour-based tracking initialization, color-based contour evolution, adaptive shape-based contour evolution for non-periodic motions, dynamic shape-based contour evolution for periodic motions, and the handling of abrupt motions. For the initialization of contour-based tracking, we develop an optical flow-based algorithm for automatically initializing contours at the first frame. For the color-based contour evolution, Markov random field theory is used to measure correlations between values of neighboring pixels for posterior probability estimation. For adaptive shape-based contour evolution, the global shape information and the local color information are combined to hierarchically evolve the contour, and a flexible shape updating model is constructed. For the dynamic shape-based contour evolution, a shape mode transition matrix is learnt to characterize the temporal correlations of object shapes. For the handling of abrupt motions, particle swarm optimization is adopted to capture the global motion which is applied to the contour in the current frame to produce an initial contour in the next frame. PMID:23288333

  10. On the relationship between photospheric footpoint motions and coronal heating in solar active regions

    SciTech Connect

    Van Ballegooijen, A. A.; Asgari-Targhi, M.; Berger, M. A.

    2014-05-20

    Coronal heating theories can be classified as either direct current (DC) or alternating current (AC) mechanisms, depending on whether the coronal magnetic field responds quasi-statically or dynamically to the photospheric footpoint motions. In this paper we investigate whether photospheric footpoint motions with velocities of 1-2 km s{sup –1} can heat the corona in active regions, and whether the corona responds quasi-statically or dynamically to such motions (DC versus AC heating). We construct three-dimensional magnetohydrodynamic models for the Alfvén waves and quasi-static perturbations generated within a coronal loop. We find that in models where the effects of the lower atmosphere are neglected, the corona responds quasi-statically to the footpoint motions (DC heating), but the energy flux into the corona is too low compared to observational requirements. In more realistic models that include the lower atmosphere, the corona responds more dynamically to the footpoint motions (AC heating) and the predicted heating rates due to Alfvén wave turbulence are sufficient to explain the observed hot loops. The higher heating rates are due to the amplification of Alfvén waves in the lower atmosphere. We conclude that magnetic braiding is a highly dynamic process.

  11. The role of passive avian head stabilization in flapping flight

    PubMed Central

    Pete, Ashley E.; Kress, Daniel; Dimitrov, Marina A.; Lentink, David

    2015-01-01

    Birds improve vision by stabilizing head position relative to their surroundings, while their body is forced up and down during flapping flight. Stabilization is facilitated by compensatory motion of the sophisticated avian head–neck system. While relative head motion has been studied in stationary and walking birds, little is known about how birds accomplish head stabilization during flapping flight. To unravel this, we approximate the avian neck with a linear mass–spring–damper system for vertical displacements, analogous to proven head stabilization models for walking humans. We corroborate the model's dimensionless natural frequency and damping ratios from high-speed video recordings of whooper swans (Cygnus cygnus) flying over a lake. The data show that flap-induced body oscillations can be passively attenuated through the neck. We find that the passive model robustly attenuates large body oscillations, even in response to head mass and gust perturbations. Our proof of principle shows that bird-inspired drones with flapping wings could record better images with a swan-inspired passive camera suspension. PMID:26311316

  12. The role of passive avian head stabilization in flapping flight.

    PubMed

    Pete, Ashley E; Kress, Daniel; Dimitrov, Marina A; Lentink, David

    2015-09-01

    Birds improve vision by stabilizing head position relative to their surroundings, while their body is forced up and down during flapping flight. Stabilization is facilitated by compensatory motion of the sophisticated avian head-neck system. While relative head motion has been studied in stationary and walking birds, little is known about how birds accomplish head stabilization during flapping flight. To unravel this, we approximate the avian neck with a linear mass-spring-damper system for vertical displacements, analogous to proven head stabilization models for walking humans. We corroborate the model's dimensionless natural frequency and damping ratios from high-speed video recordings of whooper swans (Cygnus cygnus) flying over a lake. The data show that flap-induced body oscillations can be passively attenuated through the neck. We find that the passive model robustly attenuates large body oscillations, even in response to head mass and gust perturbations. Our proof of principle shows that bird-inspired drones with flapping wings could record better images with a swan-inspired passive camera suspension.

  13. The role of passive avian head stabilization in flapping flight.

    PubMed

    Pete, Ashley E; Kress, Daniel; Dimitrov, Marina A; Lentink, David

    2015-09-01

    Birds improve vision by stabilizing head position relative to their surroundings, while their body is forced up and down during flapping flight. Stabilization is facilitated by compensatory motion of the sophisticated avian head-neck system. While relative head motion has been studied in stationary and walking birds, little is known about how birds accomplish head stabilization during flapping flight. To unravel this, we approximate the avian neck with a linear mass-spring-damper system for vertical displacements, analogous to proven head stabilization models for walking humans. We corroborate the model's dimensionless natural frequency and damping ratios from high-speed video recordings of whooper swans (Cygnus cygnus) flying over a lake. The data show that flap-induced body oscillations can be passively attenuated through the neck. We find that the passive model robustly attenuates large body oscillations, even in response to head mass and gust perturbations. Our proof of principle shows that bird-inspired drones with flapping wings could record better images with a swan-inspired passive camera suspension. PMID:26311316

  14. Unsteady Adjoint Approach for Design Optimization of Flapping Airfoils

    NASA Technical Reports Server (NTRS)

    Lee, Byung Joon; Liou, Meng-Sing

    2012-01-01

    This paper describes the work for optimizing the propulsive efficiency of flapping airfoils, i.e., improving the thrust under constraining aerodynamic work during the flapping flights by changing their shape and trajectory of motion with the unsteady discrete adjoint approach. For unsteady problems, it is essential to properly resolving time scales of motion under consideration and it must be compatible with the objective sought after. We include both the instantaneous and time-averaged (periodic) formulations in this study. For the design optimization with shape parameters or motion parameters, the time-averaged objective function is found to be more useful, while the instantaneous one is more suitable for flow control. The instantaneous objective function is operationally straightforward. On the other hand, the time-averaged objective function requires additional steps in the adjoint approach; the unsteady discrete adjoint equations for a periodic flow must be reformulated and the corresponding system of equations solved iteratively. We compare the design results from shape and trajectory optimizations and investigate the physical relevance of design variables to the flapping motion at on- and off-design conditions.

  15. Active Control of Flow Separation on a High-Lift System with Slotted Flap at High Reynolds Number

    NASA Technical Reports Server (NTRS)

    Khodadoust, Abdollah; Washburn, Anthony

    2007-01-01

    The NASA Energy Efficient Transport (EET) airfoil was tested at NASA Langley's Low- Turbulence Pressure Tunnel (LTPT) to assess the effectiveness of distributed Active Flow Control (AFC) concepts on a high-lift system at flight scale Reynolds numbers for a medium-sized transport. The test results indicate presence of strong Reynolds number effects on the high-lift system with the AFC operational, implying the importance of flight-scale testing for implementation of such systems during design of future flight vehicles with AFC. This paper describes the wind tunnel test results obtained at the LTPT for the EET high-lift system for various AFC concepts examined on this airfoil.

  16. 14 CFR 23.701 - Flap interconnection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap interconnection. 23.701 Section 23.701... Systems § 23.701 Flap interconnection. (a) The main wing flaps and related movable surfaces as a system must— (1) Be synchronized by a mechanical interconnection between the movable flap surfaces that...

  17. Molecular dynamics study of the connection between flap closing and binding of fullerene-based inhibitors of the HIV-1 protease.

    PubMed

    Zhu, Zhongwei; Schuster, David I; Tuckerman, Mark E

    2003-02-11

    The complementary spatial relationship between fullerene C(60) and the hydrophobic cavity region of the human immunodeficiency virus (HIV) protease, which houses the active site of the enzyme, has led to the suggestion that fullerene-based derivatives could have potential use as effective HIV protease inhibitors. The ability of such compounds to desolvate the cavity region leads to a strong hydrophobic interaction between the C(60) moiety and residues in the cavity region. In this study, the connection between the motion of the so-called flexible flaps of the cavity and favorable binding of a fullerene-based protease inhibitor is explored using multiple-time scale molecular dynamics simulations and free energy techniques. In addition, the effect of the interaction between the C(60) moiety and the residues in the cavity region on the water content of the cavity is also investigated. Conformational free energy profiles along a suitably chosen flap opening coordinate show a considerable barrier to flap opening in the presence of the inhibitor, while no such barrier exists for the protease alone. This result is interpreted in terms of a strong hydrophobic interaction between the C(60) moiety and the flexible flaps, which cause the latter to close tightly around the inhibitor, thereby expelling water from the cavity and leading to a favorable binding interaction. This interpretation is rationalized by direct analysis of the water content in the cavity in the presence and absence of the inhibitor.

  18. MR-based motion correction for PET imaging using wired active MR microcoils in simultaneous PET-MR: Phantom study

    SciTech Connect

    Huang, Chuan; Brady, Thomas J.; El Fakhri, Georges; Ouyang, Jinsong; Ackerman, Jerome L.; Petibon, Yoann

    2014-04-15

    Purpose: Artifacts caused by head motion present a major challenge in brain positron emission tomography (PET) imaging. The authors investigated the feasibility of using wired active MR microcoils to track head motion and incorporate the measured rigid motion fields into iterative PET reconstruction. Methods: Several wired active MR microcoils and a dedicated MR coil-tracking sequence were developed. The microcoils were attached to the outer surface of an anthropomorphic{sup 18}F-filled Hoffman phantom to mimic a brain PET scan. Complex rotation/translation motion of the phantom was induced by a balloon, which was connected to a ventilator. PET list-mode and MR tracking data were acquired simultaneously on a PET-MR scanner. The acquired dynamic PET data were reconstructed iteratively with and without motion correction. Additionally, static phantom data were acquired and used as the gold standard. Results: Motion artifacts in PET images were effectively removed by wired active MR microcoil based motion correction. Motion correction yielded an activity concentration bias ranging from −0.6% to 3.4% as compared to a bias ranging from −25.0% to 16.6% if no motion correction was applied. The contrast recovery values were improved by 37%–156% with motion correction as compared to no motion correction. The image correlation (mean ± standard deviation) between the motion corrected (uncorrected) images of 20 independent noise realizations and static reference was R{sup 2} = 0.978 ± 0.007 (0.588 ± 0.010, respectively). Conclusions: Wired active MR microcoil based motion correction significantly improves brain PET quantitative accuracy and image contrast.

  19. Wind-Tunnel Investigation of the Effect of Angle of Attack and Flapping-Hinge Offset on Periodic Bending Moments and Flapping of a Small Rotor

    NASA Technical Reports Server (NTRS)

    McCarty, John Locke; Brooks, George W.; Maglieri, Domenic J.

    1959-01-01

    A two-blade rotor having a diameter of 4 feet and a solidity of 0.037 was tested in the Langley 300-MPH 7- by 10-foot tunnel to obtain information on the effect of certain rotor variables on the blade periodic bending moments and flapping angles during the various stages of transformation between the helicopter and autogiro configuration. Variables studied included collective pitch angle, flapping-hinge offset, rotor angle of attack, and tip-speed ratio. The results show that the blade periodic bending moments generally increase with tip-speed ratio up into the transition region, diminish over a certain range of tip-speed ratio, and increase again at higher tip-speed ratios. Above the transition region, the bending moments increase with collective pitch angle and rotor angle of attack. The absence of a flapping hinge results in a significant amplification of the periodic bending moments, the magnitudes of which increase with tip-speed ratio. When the flapping hinge is used, an increase in flapping-hinge offset results in reduced period bending moments. The aforementioned trends exhibited by the bending moments for changes in the variables are essentially duplicated by the periodic flapping motions. The existence of substantial amounts of blade stall increased both the periodic bending moments and the flapping angles. Harmonic analysis of the bending moments shows significant contributions of the higher harmonics, particularly in the transition region.

  20. Active vibration isolation of macro-micro motion stage disturbances using a floating stator platform

    NASA Astrophysics Data System (ADS)

    Zhang, Lufan; Long, Zhili; Cai, Jiandong; Liu, Yang; Fang, Jiwen; Wang, Michael Yu

    2015-10-01

    Macro-micro motion stage is mainly applied in microelectronics manufacturing to realize a high-acceleration, high-speed and nano-positioning motion. The high acceleration and nano-positioning accuracy would be influenced by the vibration of the motion stage. In the paper, a concept of floating stage is introduced in the macro-micro motion for isolating vibration disturbances. The design model of the floating stage is established and its theoretical analyses including natural frequency, transient and frequency response analyses are investigated, in order to demonstrate the feasibility of the floating stator platform as a vibration isolator for the macro-micro motion stage. Moreover, an optimal design of the floating stator is conducted and then verified by experiments. In order to characterize and quantify the performance of isolation obtained from the traditional fixed stator and the floating stator, the acceleration responses at different accelerations, speeds and displacements are measured in x, y and z directions. The theoretical and experimental analyses in time and frequency domains indicate that the floating stator platform is effective to actively isolate the vibration in the macro-micro motion stage. In macro-micro motion stage, high acceleration motion is provided by VCM. Vibration is induced from VCM, that is, VCM is a source system, the vibration response or force is felt by a receiver system. Generally, VCM is fixed on the base, which means that the base is the receiver system which absorbs or transfers the vibration. However, the vibration cannot completely disappear and the base vibration is inevitable. In the paper, a floated stator platform as isolation system is developed to decrease or isolate vibration between VCM and base. The floated stator platform consists of damper, stopper, floated lock, spring, limiter, sub base, etc. Unlike the traditional stator of VCM fixed on the base, the floated stator can be moved on the linear guide under vibration

  1. Complementary limb motion estimation for the control of active knee prostheses.

    PubMed

    Vallery, Heike; Burgkart, Rainer; Hartmann, Cornelia; Mitternacht, Jürgen; Riener, Robert; Buss, Martin

    2011-02-01

    To restore walking after transfemoral amputation, various actuated exoprostheses have been developed, which control the knee torque actively or via variable damping. In both cases, an important issue is to find the appropriate control that enables user-dominated gait. Recently, we suggested a generic method to deduce intended motion of impaired or amputated limbs from residual human body motion. Based on interjoint coordination in physiological gait, statistical regression is used to estimate missing motion. In a pilot study, this complementary limb motion estimation (CLME) strategy is applied to control an active knee exoprosthesis. A motor-driven prosthetic knee with one degree of freedom has been realized, and one above-knee amputee has used it with CLME. Performed tasks are walking on a treadmill and alternating stair ascent and descent. The subject was able to walk on the treadmill at varying speeds, but needed assistance with the stairs, especially to descend. The promising results with CLME are compared with the subject's performance with her own prosthesis, the C-Leg from Otto Bock.

  2. Complementary limb motion estimation for the control of active knee prostheses.

    PubMed

    Vallery, Heike; Burgkart, Rainer; Hartmann, Cornelia; Mitternacht, Jürgen; Riener, Robert; Buss, Martin

    2011-02-01

    To restore walking after transfemoral amputation, various actuated exoprostheses have been developed, which control the knee torque actively or via variable damping. In both cases, an important issue is to find the appropriate control that enables user-dominated gait. Recently, we suggested a generic method to deduce intended motion of impaired or amputated limbs from residual human body motion. Based on interjoint coordination in physiological gait, statistical regression is used to estimate missing motion. In a pilot study, this complementary limb motion estimation (CLME) strategy is applied to control an active knee exoprosthesis. A motor-driven prosthetic knee with one degree of freedom has been realized, and one above-knee amputee has used it with CLME. Performed tasks are walking on a treadmill and alternating stair ascent and descent. The subject was able to walk on the treadmill at varying speeds, but needed assistance with the stairs, especially to descend. The promising results with CLME are compared with the subject's performance with her own prosthesis, the C-Leg from Otto Bock. PMID:21303189

  3. Flap Conformations in HIV-1 Protease are Altered by Mutations

    NASA Astrophysics Data System (ADS)

    Fanucci, Gail; Blackburn, Mandy; Veloro, Angelo; Galiano, Luis; Fangu, Ding; Simmerling, Carlos

    2009-03-01

    HIV-1 protease (PR) is an enzyme that is a major drug target in the treatment of AIDS. Although the structure and function of HIV-1 PR have been studied for over 20 years, questions remain regarding the conformations and dynamics of the β-hairpin turns (flaps) that cover the active site cavity. Distance measurements with pulsed EPR spectroscopy of spin labeled constructs of HIV-1 PR have been used to characterize the flap conformations in the apo and inhibitor bound states. From the most probably distances and the breadth of the distance distribution profiles from analysis of the EPR data, insights regarding the flap conformations and flexibility are gained. The EPR results clearly show how drug pressure selected mutations alter the average conformation of the flaps and the degree of opening of the flaps. Molecular dynamics simulations successfully regenerate the experimentally determined distance distribution profiles, and more importantly, provide structural models for full interpretation of the EPR results. By combining experiment and theory to understand the role that altered flap flexibility/conformations play in the mechanism of drug resistance, key insights are gained toward the rational development of new inhibitors of this important enzyme.

  4. Effects of calcitriol on random skin flap survival in rats.

    PubMed

    Zhou, Kai-liang; Zhang, Yi-hui; Lin, Ding-sheng; Tao, Xian-yao; Xu, Hua-zi

    2016-01-01

    Calcitriol, a metabolite of vitamin D, is often used in osteoporosis clinics. However, the material has other bioactivities; for example, it accelerates angiogenesis, has anti-inflammatory properties, and inhibits oxidative stress. We investigated the effects of calcitriol in a random skin flap rat model. "McFarlane flap" models were established in 84 male Sprague Dawley rats, divided into two groups. One group received intraperitoneal injections of calcitriol (2 μg/kg/day) whereas control rats received intraperitoneal injections of saline. The percentage flap survival area and tissue water content were measured 7 days later, which showed that calcitriol improved flap survival area and reduced tissue edema. It also increased the mean vessel density and upregulated levels of VEGF mRNA/protein, both of which promote flap angiogenesis. Moreover, it decreased leukocyte and macrophage infiltration, reduced the inflammatory proteins IL1β and IL6, increased SOD activity, decreased MDA content, and upregulated the level of autophagy. Overall, our results suggest that calcitriol promotes skin flap survival by accelerating angiogenesis, having anti-inflammatory effects, reducing oxidative stress, and promoting autophagy. PMID:26732750

  5. Biocatalyst activity in nonaqueous environments correlates with centisecond-range protein motions.

    PubMed

    Eppler, Ross K; Hudson, Elton P; Chase, Shannon D; Dordick, Jonathan S; Reimer, Jeffrey A; Clark, Douglas S

    2008-10-14

    Recent studies exploring the relationship between enzymatic catalysis and protein dynamics in the aqueous phase have yielded evidence that dynamics and enzyme activity are strongly correlated. Given that protein dynamics are significantly attenuated in organic solvents and that proteins exhibit a wide range of motions depending on the specific solvent environment, the nonaqueous milieu provides a unique opportunity to examine the role of protein dynamics in enzyme activity. Variable-temperature kinetic measurements, X-band electron spin resonance spectroscopy, (1)H NMR relaxation, and (19)F NMR spectroscopy experiments were performed on subtilisin Carlsberg colyophilized with several inorganic salts and suspended in organic solvents. The results indicate that salt activation induces a greater degree of transition-state flexibility, reflected by a more positive DeltaDeltaS(dagger), for the more active biocatalyst preparations in organic solvents. In contrast, DeltaDeltaH(dagger) was negligible regardless of salt type or salt content. Electron spin resonance spectroscopy and (1)H NMR relaxation measurements, including spin-lattice relaxation, spin-lattice relaxation in the rotating frame, and longitudinal magnetization exchange, revealed that the enzyme's turnover number (k(cat)) was strongly correlated with protein motions in the centisecond time regime, weakly correlated with protein motions in the millisecond regime, and uncorrelated with protein motions on the piconanosecond timescale. In addition, (19)F chemical shift measurements and hyperfine tensor measurements of biocatalyst formulations inhibited with 4-fluorobenzenesulfonyl fluoride and 4-ethoxyfluorophosphinyl-oxy-TEMPO, respectively, suggest that enzyme activation was only weakly affected by changes in active-site polarity. PMID:18840689

  6. Examining the Magnetic Field Strength and the Horizontal and Vertical Motions in an Emerging Active Region

    NASA Astrophysics Data System (ADS)

    Lin, Chia-Hsien; Chen, Yu-Che

    2016-03-01

    Earlier observational studies have used the time evolution of emerging magnetic flux regions at the photosphere to infer their subsurface structures, assuming that the flux structure does not change significantly over the near-surface layer. In this study, we test the validity of this assumption by comparing the horizontal and vertical motions of an emerging active region. The two motions would be correlated if the emerging structure is rigid. The selected active region (AR) NOAA 11645 is not embedded in detectable preexisting magnetic field. The observed horizontal motion is quantified by the separation of the two AR polarities and the width of the region. The vertical motion is derived from the magnetic buoyancy theory. Our results show that the separation of the polarities is fastest at the beginning with a velocity of {≈ }4 Mm hr^{-1} and decreases to ≤ 1 Mm hr^{-1} after the main growing phase of flux emergence. The derived thick flux-tube buoyant velocity is between 1 and 3 Mm hr^{-1}, while the thin flux-tube approximation results in an unreasonably high buoyant velocity, consistent with the expectation that the approximation is inappropriate at the surface layer. The observed horizontal motion is not found to directly correlate with either the magnetic field strength or the derived buoyant velocities. However, the percentage of the horizontally oriented fields and the temporal derivatives of the field strength and the buoyant velocity show some positive correlations with the separation velocity. The results of this study imply that the assumption that the emerging active region is the cross section of a rising flux tube whose structure can be considered rigid as it rises through the near-surface layer should be taken with caution.

  7. Musculocutaneous flaps in head and neck reconstruction.

    PubMed Central

    Leonard, A. G.

    1989-01-01

    The introduction of musculocutaneous flaps to head and neck reconstructive surgery is described. The flaps available are listed, and the most important ones described and illustrated. Both the latissimus dorsi and pectoralis major flaps are felt to have a role in head and neck reconstruction, though they have largely been superseded by microvascular free flaps such as the radial forearm flap. Images fig. 1 fig. 2 fig. 3 fig. 4 fig. 5 fig. 6 fig. 7 fig. 8 PMID:2686511

  8. Radiated noise from an externally blown flap

    NASA Technical Reports Server (NTRS)

    Reddy, N. N.; Yu, J. C.

    1975-01-01

    The far field noise from subsonic jet impingement on a wing-flap with a 45 deg bend was experimentally investigated. The test parameters are jet Mach number and flap length. For long flaps, the primary source mechanisms are found to be turbulent mixing and flow impingement. For short flaps, the interaction of turbulent flow with the flap trailing edge appears to strongly influence the radiated noise.

  9. Nonlinear flap-lag axial equations of a rotating beam

    NASA Technical Reports Server (NTRS)

    Kaza, K. R. V.; Kvaternik, R. G.

    1977-01-01

    It is possible to identify essentially four approaches by which analysts have established either the linear or nonlinear governing equations of motion for a particular problem related to the dynamics of rotating elastic bodies. The approaches include the effective applied load artifice in combination with a variational principle and the use of Newton's second law, written as D'Alembert's principle, applied to the deformed configuration. A third approach is a variational method in which nonlinear strain-displacement relations and a first-degree displacement field are used. The method introduced by Vigneron (1975) for deriving the linear flap-lag equations of a rotating beam constitutes the fourth approach. The reported investigation shows that all four approaches make use of the geometric nonlinear theory of elasticity. An alternative method for deriving the nonlinear coupled flap-lag-axial equations of motion is also discussed.

  10. Flap Edge Noise Reduction Fins

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R. (Inventor); Choudhan, Meelan M. (Inventor)

    2015-01-01

    A flap of the type that is movably connected to an aircraft wing to provide control of an aircraft in flight includes opposite ends, wherein at least a first opposite end includes a plurality of substantially rigid, laterally extending protrusions that are spaced apart to form a plurality of fluidly interconnected passageways. The passageways have openings adjacent to upper and lower sides of the flap, and the passageways include a plurality of bends such that high pressure fluid flows from a high pressure region to a low pressure region to provide a boundary condition that inhibits noise resulting from airflow around the end of the flap.

  11. Coupling of postural activity with motion of a ship at sea.

    PubMed

    Varlet, Manuel; Bardy, Benoît G; Chen, Fu-Chen; Alcantara, Cristina; Stoffregen, Thomas A

    2015-05-01

    On land, body sway during stance becomes coupled with imposed oscillations of the illuminated environment or of the support surface. This coupling appears to have the function of stabilizing the body relative to the illuminated or inertial environment. In previous research, the stimulus has been limited to motion in a single axis. Little is known about our ability to couple postural activity with complex, multi-axis oscillations. On a ship at sea, we evaluated postural activity using measures of body movement, as such, and we separately evaluated a direct measure of coupling between body movement and ship motion. Participants were tested while facing fore-aft and athwartship. We compared postural activity between participants who had been seasick at the beginning of the voyage and those who had not. Coupling of postural activity with ship motion differed between body axes as a function of body orientation relative to the ship. In addition, coupling differed between participants who had been seasick at the beginning of the voyage and those who had not. We discuss the results in terms of implications for general theories of postural control, and for prediction of susceptibility to seasickness in individuals.

  12. Meridional motions of sunspots from 1947.9 to 1985.0. II - Latitude motions dependent on SPOT type and phase of the activity cycle

    NASA Astrophysics Data System (ADS)

    Lustig, G.; Hanslmeier, A.

    1987-01-01

    The dependence of the meridional motions of sunspots on sunspot-type and phase in the solar activity cycle for the time interval 1947.9-1985.0 is examined; this was done also with the sunspot data from the solar-observatory Kanzelhoehe. For the total time interval, investigations for each cycle were carried out only for the elder or long lasting G, H, and J sunspot groups and distinctions between similar sunspot types AB, C, D, EF, GHJ (Zuerich-classification). The meridional motions about the different activity maxima were also examined. In all investigations in the period from 1947.9 to 1985.0 a tendency to a southdrift can be observed on both hemispheres of the sun, but the mean meridional motions are between the error-bars not very significantly different from zero.

  13. An experimental study of spanwise flow effects on lift generation in flapping wings

    NASA Astrophysics Data System (ADS)

    Hong, Youngsun

    Using a combination of force transducer measurement to quantify net lift force, a high frame rate camera to quantify and subtract inertial contributions, and Digital Particle Image Velocimetry (DPIV) to calculate aerodynamic contributions in the spanwise plane, the contribution of spanwise flow to the generation of lift force in wings undergoing a pure flapping motion in hover is shown as a function of flapping angle throughout the flapping cycle. When flapping a flat plate wing and a wing of identical wing area and aspect ratio, but cambered in span (both wings in hover with no change in pitch), the spanwise cambered wing was found to generate a greater mean lift force through the whole flap cycle under the same acceleration. However, depending on the angle in flapping arc, the spanwise cambered wing can generate less lift than the flat wing. Additionally, since the lift force generated by the wingtip vortex in the spanwise plane resulting from the flapping motion has yet to be directly quantified, the wingtip vortex is investigated to determine precisely how it augments the lift force through the various phases in the flapping motion. Vortices in the vicinity of the wingtip generate lift force in the spanwise plane of flapping wings. In classical fixed wing aerodynamics, the presence of wing tip vortices has been shown to increase the lift locally near the tip. Also, the impingement of large vortices on the upper surface of delta wings is considered to contribute largely to the lift force at higher angles of attack. This study determined that vortices in the spanwise plane (streamwise vorticity) generate lift in a similar manner in flapping wings. Using a mechanical ornithopter with wings fabricated in-house, vortices were identified at several different locations along the span of the wing, and at numerous different points throughout the flapping cycle under a variety of operating conditions. The lift generated by these spanwise planar oriented vortices was

  14. 14 CFR 23.779 - Motion and effect of cockpit controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Aerodynamic controls: Motion and effect (1) Primary controls: Aileron Right (clockwise) for right wing down... auxiliary lift devices) Forward or up for flaps up or auxiliary device stowed; rearward or down for flaps down or auxiliary device deployed. Trim tabs (or equivalent) Switch motion or mechanical rotation...

  15. 14 CFR 25.779 - Motion and effect of cockpit controls.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... Controls Motion and effect Aileron Right (clockwise) for right wing down. Elevator Rearward for nose up... lift devices) Forward for flaps up; rearward for flaps down. Trim tabs (or equivalent) Rotate to...) Auxiliary. Controls Motion and effect Landing gear Down to extend....

  16. ``Schooling'' of wing pairs in flapping flight

    NASA Astrophysics Data System (ADS)

    Ramananarivo, Sophie; Zhang, Jun; Ristroph, Leif; AML, Courant Collaboration; Physics NYU Collaboration

    2015-11-01

    The experimental setup implements two independent flapping wings swimming in tandem. Both are driven with the same prescribed vertical heaving motion, but the horizontal motion is free, which means that the swimmers can take up any relative position and forward speed. Experiments show however clearly coordinated motions, where the pair of wings `crystallize' into specific stable arrangements. The follower wing locks into the path of the leader, adopting its speed, and with a separation distance that takes on one of several discrete values. By systematically varying the kinematics and wing size, we show that the set of stable spacings is dictated by the wavelength of the periodic wake structure. The forces maintaining the pair cohesion are characterized by applying an external force to the follower to perturb it away from the `stable wells'. These results show that hydrodynamics alone is sufficient to induce cohesive and coordinated collective locomotion through a fluid, and we discuss the hypothesis that fish schools and bird flocks also represent stable modes of motion.

  17. 14 CFR 25.779 - Motion and effect of cockpit controls.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... Controls Motion and effect Aileron Right (clockwise) for right wing down. Elevator Rearward for nose up. Rudder Right pedal forward for nose right. (2) Secondary. Controls Motion and effect Flaps (or...

  18. 14 CFR 25.779 - Motion and effect of cockpit controls.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .... Controls Motion and effect Aileron Right (clockwise) for right wing down. Elevator Rearward for nose up. Rudder Right pedal forward for nose right. (2) Secondary. Controls Motion and effect Flaps (or...

  19. 14 CFR 25.779 - Motion and effect of cockpit controls.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .... Controls Motion and effect Aileron Right (clockwise) for right wing down. Elevator Rearward for nose up. Rudder Right pedal forward for nose right. (2) Secondary. Controls Motion and effect Flaps (or...

  20. Efficiency of lift production in flapping and gliding flight of swifts.

    PubMed

    Henningsson, Per; Hedenström, Anders; Bomphrey, Richard J

    2014-01-01

    Many flying animals use both flapping and gliding flight as part of their routine behaviour. These two kinematic patterns impose conflicting requirements on wing design for aerodynamic efficiency and, in the absence of extreme morphing, wings cannot be optimised for both flight modes. In gliding flight, the wing experiences uniform incident flow and the optimal shape is a high aspect ratio wing with an elliptical planform. In flapping flight, on the other hand, the wing tip travels faster than the root, creating a spanwise velocity gradient. To compensate, the optimal wing shape should taper towards the tip (reducing the local chord) and/or twist from root to tip (reducing local angle of attack). We hypothesised that, if a bird is limited in its ability to morph its wings and adapt its wing shape to suit both flight modes, then a preference towards flapping flight optimization will be expected since this is the most energetically demanding flight mode. We tested this by studying a well-known flap-gliding species, the common swift, by measuring the wakes generated by two birds, one in gliding and one in flapping flight in a wind tunnel. We calculated span efficiency, the efficiency of lift production, and found that the flapping swift had consistently higher span efficiency than the gliding swift. This supports our hypothesis and suggests that even though swifts have been shown previously to increase their lift-to-drag ratio substantially when gliding, the wing morphology is tuned to be more aerodynamically efficient in generating lift during flapping. Since body drag can be assumed to be similar for both flapping and gliding, it follows that the higher total drag in flapping flight compared with gliding flight is primarily a consequence of an increase in wing profile drag due to the flapping motion, exceeding the reduction in induced drag. PMID:24587260

  1. Efficiency of Lift Production in Flapping and Gliding Flight of Swifts

    PubMed Central

    Henningsson, Per; Hedenström, Anders; Bomphrey, Richard J.

    2014-01-01

    Many flying animals use both flapping and gliding flight as part of their routine behaviour. These two kinematic patterns impose conflicting requirements on wing design for aerodynamic efficiency and, in the absence of extreme morphing, wings cannot be optimised for both flight modes. In gliding flight, the wing experiences uniform incident flow and the optimal shape is a high aspect ratio wing with an elliptical planform. In flapping flight, on the other hand, the wing tip travels faster than the root, creating a spanwise velocity gradient. To compensate, the optimal wing shape should taper towards the tip (reducing the local chord) and/or twist from root to tip (reducing local angle of attack). We hypothesised that, if a bird is limited in its ability to morph its wings and adapt its wing shape to suit both flight modes, then a preference towards flapping flight optimization will be expected since this is the most energetically demanding flight mode. We tested this by studying a well-known flap-gliding species, the common swift, by measuring the wakes generated by two birds, one in gliding and one in flapping flight in a wind tunnel. We calculated span efficiency, the efficiency of lift production, and found that the flapping swift had consistently higher span efficiency than the gliding swift. This supports our hypothesis and suggests that even though swifts have been shown previously to increase their lift-to-drag ratio substantially when gliding, the wing morphology is tuned to be more aerodynamically efficient in generating lift during flapping. Since body drag can be assumed to be similar for both flapping and gliding, it follows that the higher total drag in flapping flight compared with gliding flight is primarily a consequence of an increase in wing profile drag due to the flapping motion, exceeding the reduction in induced drag. PMID:24587260

  2. Conformational Flexibility in the Flap Domains of Ligand-Free HIV Protease

    SciTech Connect

    Heaslet, H.; Rosenfeld, R.; Giffin, M.; Lin, Y.-C.; Tam, K.; Torbett, B.E.; Elder, J.H.; Stout, C.D.

    2009-06-01

    The crystal structures of wild-type HIV protease (HIV PR) in the absence of substrate or inhibitor in two related crystal forms at 1.4 and 2.15 {angstrom} resolution are reported. In one crystal form HIV PR adopts an 'open' conformation with a 7.7 {angstrom} separation between the tips of the flaps in the homodimer. In the other crystal form the tips of the flaps are 'curled' towards the 80s loop, forming contacts across the local twofold axis. The 2.3 {angstrom} resolution crystal structure of a sixfold mutant of HIV PR in the absence of substrate or inhibitor is also reported. The mutant HIV PR, which evolved in response to treatment with the potent inhibitor TL-3, contains six point mutations relative to the wild-type enzyme (L24I, M46I, F53L, L63P, V77I, V82A). In this structure the flaps also adopt a 'curled' conformation, but are separated and not in contact. Comparison of the apo structures to those with TL-3 bound demonstrates the extent of conformational change induced by inhibitor binding, which includes reorganization of the packing between twofold-related flaps. Further comparison with six other apo HIV PR structures reveals that the 'open' and 'curled' conformations define two distinct families in HIV PR. These conformational states include hinge motion of residues at either end of the flaps, opening and closing the entire {beta}-loop, and translational motion of the flap normal to the dimer twofold axis and relative to the 80s loop. The alternate conformations also entail changes in the {beta}-turn at the tip of the flap. These observations provide insight into the plasticity of the flap domains, the nature of their motions and their critical role in binding substrates and inhibitors.

  3. Flap monitoring using infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Keller, Alex; Wright, Leigh P.; Elmandjra, Mohamed; Mao, Jian-min

    2006-02-01

    We report results of clinical trials on flap monitoring in 65 plastic surgeries. Hemoglobin oxygen saturation of flap tissue (StO II) was monitored non-invasively by using ODISsey TM tissue oximeter, an infrared spectroscopic device. StO II measurements were conducted both intra-operatively and post-operatively. From the intra-operative measurements, we observed that StO II values dropped when the main blood vessels supplying the flap were clamped in surgery, and that StO II jumped after anastomosis to a value close to its pre-operative value. From post-operative monitoring measurements for the 65 flap cases, each lasted two days or so, we found that the StO II values approach to a level close to the baseline if the surgery was successful, and that the StO II value dropped to a value below 30% if there is a perfusion compromise, such as vascular thrombosis.

  4. Managing Flap Vortices via Separation Control

    NASA Technical Reports Server (NTRS)

    Greenblatt, David

    2006-01-01

    A pilot study was conducted on a flapped semi-span model to investigate the concept and viability of near-wake vortex management by means of boundary layer separation control. Passive control was achieved using a simple fairing and active control was achieved via zero mass-flux blowing slots. Vortex sheet strength, estimated by integrating surface pressures, was used to predict vortex characteristics based on inviscid rollup relations and vortices trailing the flaps were mapped using a seven-hole probe. Separation control was found to have a marked effect on vortex location, strength, tangential velocity, axial velocity and size over a wide range of angles of attack and control conditions. In general, the vortex trends were well predicted by the inviscid rollup relations. Manipulation of the separated flow near the flap edges exerted significant control over either outboard or inboard edge vortices while producing small lift and moment excursions. Unsteady surface pressures indicated that dynamic separation and attachment control can be exploited to perturb vortices at wavelengths shorter than a typical wingspan. In summary, separation control has the potential for application to time-independent or time-dependent wake alleviation schemes, where the latter can be deployed to minimize adverse effects on ride-quality and dynamic structural loading.

  5. Use of passively actuated flaps for enhanced lift for pitching and heaving airfoils

    NASA Astrophysics Data System (ADS)

    Siala, Firas; Planck, Cameron; Liburdy, James

    2014-11-01

    The enhanced lift and reduced drag obtained by applying passively actuated leading and trailing flaps to a low aspect ratio flat wing during heaving and pitching at moderate Reynolds numbers (104) is demonstrated. Direct force measurements are obtained during the cyclic motion and are synchronized with the tracking of the motion of the passive flaps. The flaps are controlled using torsion springs and their natural frequency is found to play a dominant role in determining the lift enhancement. Results are shown for a range of heaving and pitching conditions of amplitude and frequency, with the pitching phase offset ninety degrees from the heaving. Flow visualization is used to document the transient wake conditions. The lift and drag forces are shown to be enhanced near the peak effective angle of attack during the cycling motion resulting in a net mean lift increase.

  6. Full scale upper surface blown flap noise

    NASA Technical Reports Server (NTRS)

    Heidelberg, L. J.; Homyak, L.; Jones, W. L.

    1975-01-01

    A highly noise suppressed TF 34 engine was used to investigate the noise of several powered lift configurations involving upper surface blown (USB) flaps. The configuration variables were nozzle type (i.e. slot and circular with deflector), flap chord length, and flap angle. The results of velocity surveys at both the nozzle exit and the flap trailing edge are also presented and used for correlation of the noise data. Configurations using a long flap design were 4 db quieter than a short flap typical of current trends in USB flap design. The lower noise for the long flap is attributed primarily to the greater velocity decay of the jet at the flap trailing edge. The full-scale data revealed substantially more quadrupole noise in the region near the deflected jet than observed in previous sub-scale tests.

  7. Physiological, aerodynamic and geometric constraints of flapping account for bird gaits, and bounding and flap-gliding flight strategies.

    PubMed

    Usherwood, James Richard

    2016-11-01

    Aerodynamically economical flight is steady and level. The high-amplitude flapping and bounding flight style of many small birds departs considerably from any aerodynamic or purely mechanical optimum. Further, many large birds adopt a flap-glide flight style in cruising flight which is not consistent with purely aerodynamic economy. Here, an account is made for such strategies by noting a well-described, general, physiological cost parameter of muscle: the cost of activation. Small birds, with brief downstrokes, experience disproportionately high costs due to muscle activation for power during contraction as opposed to work. Bounding flight may be an adaptation to modulate mean aerodynamic force production in response to (1) physiological pressure to extend the duration of downstroke to reduce power demands during contraction; (2) the prevention of a low-speed downstroke due to the geometric constraints of producing thrust; (3) an aerodynamic cost to flapping with very low lift coefficients. In contrast, flap-gliding birds, which tend to be larger, adopt a strategy that reduces the physiological cost of work due both to activation and contraction efficiency. Flap-gliding allows, despite constraints to modulation of aerodynamic force lever-arm, (1) adoption of moderately large wing-stroke amplitudes to achieve suitable muscle strains, thereby reducing the activation costs for work; (2) reasonably quick downstrokes, enabling muscle contraction at efficient velocities, while being (3) prevented from very slow weight-supporting upstrokes due to the cost of performing 'negative' muscle work.

  8. Physiological, aerodynamic and geometric constraints of flapping account for bird gaits, and bounding and flap-gliding flight strategies.

    PubMed

    Usherwood, James Richard

    2016-11-01

    Aerodynamically economical flight is steady and level. The high-amplitude flapping and bounding flight style of many small birds departs considerably from any aerodynamic or purely mechanical optimum. Further, many large birds adopt a flap-glide flight style in cruising flight which is not consistent with purely aerodynamic economy. Here, an account is made for such strategies by noting a well-described, general, physiological cost parameter of muscle: the cost of activation. Small birds, with brief downstrokes, experience disproportionately high costs due to muscle activation for power during contraction as opposed to work. Bounding flight may be an adaptation to modulate mean aerodynamic force production in response to (1) physiological pressure to extend the duration of downstroke to reduce power demands during contraction; (2) the prevention of a low-speed downstroke due to the geometric constraints of producing thrust; (3) an aerodynamic cost to flapping with very low lift coefficients. In contrast, flap-gliding birds, which tend to be larger, adopt a strategy that reduces the physiological cost of work due both to activation and contraction efficiency. Flap-gliding allows, despite constraints to modulation of aerodynamic force lever-arm, (1) adoption of moderately large wing-stroke amplitudes to achieve suitable muscle strains, thereby reducing the activation costs for work; (2) reasonably quick downstrokes, enabling muscle contraction at efficient velocities, while being (3) prevented from very slow weight-supporting upstrokes due to the cost of performing 'negative' muscle work. PMID:27418386

  9. Aerodynamic effects of corrugation and deformation in flapping wings of hovering hoverflies.

    PubMed

    Du, Gang; Sun, Mao

    2012-05-01

    We investigated the aerodynamic effects of wing deformation and corrugation of a three-dimensional model hoverfly wing at a hovering condition by solving the Navier-Stokes equations on a dynamically deforming grid. Various corrugated wing models were tested. Insight into whether or not there existed significant aerodynamic coupling between wing deformation (camber and twist) and wing corrugation was obtained by comparing aerodynamic forces of four cases: a smooth-plate wing in flapping motion without deformation (i.e. a rigid flat-plate wing in flapping motion); a smooth-plate wing in flapping motion with deformation; a corrugated wing in flapping motion without deformation (i.e. a rigid corrugated wing in flapping motion); a corrugated wing in flapping motion with deformation. There was little aerodynamic coupling between wing deformation and corrugation: the aerodynamic effect of wing deformation and corrugation acting together was approximately a superposition of those of deformation and corrugation acting separately. When acting alone, the effect of wing deformation was to increase the lift by 9.7% and decrease the torque (or aerodynamic power) by 5.2%, and that of wing corrugation was to decrease the lift by 6.5% and increase the torque by 2.2%. But when acting together, the wing deformation and corrugation only increased the lift by ~3% and decreased the torque by ~3%. That is, the combined aerodynamic effect of deformation and corrugation is rather small. Thus, wing corrugation is mainly for structural, not aerodynamic, purpose, and in computing or measuring the aerodynamic forces, using a rigid flat-plate wing to model the corrugated deforming wing at hovering condition can be a good approximation. PMID:22266123

  10. Aerodynamic effects of corrugation and deformation in flapping wings of hovering hoverflies.

    PubMed

    Du, Gang; Sun, Mao

    2012-05-01

    We investigated the aerodynamic effects of wing deformation and corrugation of a three-dimensional model hoverfly wing at a hovering condition by solving the Navier-Stokes equations on a dynamically deforming grid. Various corrugated wing models were tested. Insight into whether or not there existed significant aerodynamic coupling between wing deformation (camber and twist) and wing corrugation was obtained by comparing aerodynamic forces of four cases: a smooth-plate wing in flapping motion without deformation (i.e. a rigid flat-plate wing in flapping motion); a smooth-plate wing in flapping motion with deformation; a corrugated wing in flapping motion without deformation (i.e. a rigid corrugated wing in flapping motion); a corrugated wing in flapping motion with deformation. There was little aerodynamic coupling between wing deformation and corrugation: the aerodynamic effect of wing deformation and corrugation acting together was approximately a superposition of those of deformation and corrugation acting separately. When acting alone, the effect of wing deformation was to increase the lift by 9.7% and decrease the torque (or aerodynamic power) by 5.2%, and that of wing corrugation was to decrease the lift by 6.5% and increase the torque by 2.2%. But when acting together, the wing deformation and corrugation only increased the lift by ~3% and decreased the torque by ~3%. That is, the combined aerodynamic effect of deformation and corrugation is rather small. Thus, wing corrugation is mainly for structural, not aerodynamic, purpose, and in computing or measuring the aerodynamic forces, using a rigid flat-plate wing to model the corrugated deforming wing at hovering condition can be a good approximation.

  11. The Role of Muscle Flaps for Salvage of Failed Perforator Free Flaps

    PubMed Central

    2015-01-01

    Background: Despite the most heroic efforts, sometimes free flaps fail. Perforator free flaps are not invincible and can suffer the same fate. The real challenge is how to decide what is the next best choice for achieving the desired outcome. Methods: Over the past decade, 298 free perforator flaps were used in our institution. Total failure occurred in 16 patients, and partial failure requiring a second free flap occurred in an additional 6 patients for a true success rate of 93%. All failures had some form of secondary vascularized tissue transfer, which included the use of muscle flaps in 9 (41%) different patients. Results: Initial flap salvage after a failed perforator free flap was attempted with 12 perforator and 5 muscle free flaps as well as 1 perforator and 2 muscle local flaps. These were not all successful, with loss of 3 muscle free flaps and 3 perforator flaps. Tertiary free flap coverage was successful in 3 cases using 2 muscle flaps and 1 perforator free flap. Local fasciocutaneous flaps or primary wound closure was used in the remaining individuals. Conclusions: Microsurgical tissue transfers can be the most rewarding and at the same time the most challenging reconstructive endeavor. Persistence in achieving the desired outcome can require multiple steps. Perforator flaps are an important asset to obtain this goal. However, muscle flaps can still be a useful alternative, and the message is that they should not be overlooked as sometimes a viable option. PMID:26893989

  12. Active control of heave motion for TLP-type offshore platform under random waves

    NASA Astrophysics Data System (ADS)

    Battista, Ronaldo C.; Alves, Rosane M.

    1999-05-01

    In deep waters scenarios Tension Leg Platforms (TLP), under severe sea/wind conditions, may experience large response amplitudes of the hull motion. Large heave amplitudes caused by random dynamic loads appear as one of the most deleterious effects to the structural safety and integrity of the most critical components: mooring system and the handing risers. In a preliminary design reduction of these amplitudes is in general tentatively sought by compromised measures and concurrent design criteria like: high flutuability and deck payload vs. tendons and risers submerged weight; deck hydrodynamic vs. length variation of pretension tendons, etc. This paper shows that active control system may be installed inside the hull to attenuate dynamic amplitudes in heave motion. Optimal control theory are applicated for the idealization of mechanism to reduce the dynamic response amplitude, improving the safety conditions and increasing service life of tendons and risers, insuring the system functioning at all. The uncontrolled and controlled dynamic behaviors of a TLP prototype are investigated by using simplified mathematical models. The numerical results lead to the conclusion that active systems have good performance and efficiency in reducing and controlling the heave motion amplitudes and consequently the stress variations in tendons and risers of a TLP.

  13. A pertinent solution of helicopter rotor flapping stability

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1972-01-01

    The stability of the flapping motion of a single blade of a helicopter rotor is examined using the techniques of perturbation theory. The equation of motion studied is linear, with periodic aerodynamic coefficients due to the forward speed of the rotor. Solutions are found for four cases: small and large advance ratio and small and large Lock number. The perturbation techniques appropriate to each case are discussed and illustrated in the course of the analysis. The application of perturbation techniques to other problems in rotor dynamics is discussed. It is concluded that perturbation theory is a powerful mathematical technique which should prove very useful in analyzing some of the problems of helicopter dynamics.

  14. Dynamics, stability, and control analyses of flapping wing micro-air vehicles

    NASA Astrophysics Data System (ADS)

    Orlowski, Christopher T.; Girard, Anouck R.

    2012-05-01

    The paper presents an overview of the various analyses of flight dynamics, stability, and control of flapping wing micro-air vehicles available in the literature. The potential benefits of flapping wing micro-air vehicles for civil, military, and search and rescue operations are numerous. The majority of the flight dynamics research involves the standard aircraft (6DOF) equations of motion, although a growth is evident in examining the multibody flight dynamics models of flapping wing micro-air vehicles. The stability of flapping wing micro-air vehicles is largely studied in the vicinity of hover and forward flight. The majority of stability studies focus on linear, time-invariant stability in the vicinity of reference flight conditions, such as hover or forward flight. The consistent result is that flapping wing micro-air vehicles are unstable in an open loop setting. The unstable result is based on linear and nonlinear stability analyses. Control has been demonstrated for hovering and forward flight through various methods, both linear and nonlinear in nature. The entirety of reported research into the stability and control of flapping wing micro-air vehicles has neglected the mass effects of the wings on the position and orientation of the central body. Successful control of a flapping wing micro-air vehicle, with the wings' mass effects included, is still an open research area.

  15. Arm position influences the activation patterns of trunk muscles during trunk range-of-motion movements.

    PubMed

    Siu, Aaron; Schinkel-Ivy, Alison; Drake, Janessa Dm

    2016-10-01

    To understand the activation patterns of the trunk musculature, it is also important to consider the implications of adjacent structures such as the upper limbs, and the muscles that act to move the arms. This study investigated the effects of arm positions on the activation patterns and co-activation of the trunk musculature and muscles that move the arm during trunk range-of-motion movements (maximum trunk axial twist, flexion, and lateral bend). Fifteen males and fifteen females, asymptomatic for low back pain, performed maximum trunk range-of-motion movements, with three arm positions for axial twist (loose, crossed, abducted) and two positions for flexion and lateral bend (loose, crossed). Electromyographical data were collected for eight muscles bilaterally, and activation signals were cross-correlated between trunk muscles and the muscles that move the arms (upper trapezius, latissimus dorsi). Results revealed consistently greater muscle co-activation (higher cross-correlation coefficients) between the trunk muscles and upper trapezius for the abducted arm position during maximum trunk axial twist, while results for the latissimus dorsi-trunk pairings were more dependent on the specific trunk muscles (either abdominal or back) and latissimus dorsi muscle (either right or left side), as well as the range-of-motion movement. The findings of this study contribute to the understanding of interactions between the upper limbs and trunk, and highlight the influence of arm positions on the trunk musculature. In addition, the comparison of the present results to those of individuals with back or shoulder conditions may ultimately aid in elucidating underlying mechanisms or contributing factors to those conditions.

  16. Blade-mounted trailing edge flap control for BVI noise reduction

    NASA Technical Reports Server (NTRS)

    Hassan, A. A.; Charles, B. D.; Tadghighi, H.; Sankar, L. N.

    1992-01-01

    Numerical procedures based on the 2-D and 3-D full potential equations and the 2-D Navier-Stokes equations were developed to study the effects of leading and trailing edge flap motions on the aerodynamics of parallel airfoil-vortex interactions and on the aerodynamics and acoustics of the more general self-generated rotor blade vortex interactions (BVI). For subcritical interactions, the 2-D results indicate that the trailing edge flap can be used to alleviate the impulsive loads experienced by the airfoil. For supercritical interactions, the results show the necessity of using a leading edge flap, rather than a trailing edge flap, to alleviate the interaction. Results for various time dependent flap motions and their effect on the predicted temporal sectional loads, differential pressures, and the free vortex trajectories are presented. For the OLS model rotor, contours of a BVI noise metric were used to quantify the effects of the trailing edge flap on the size and directivity of the high/low intensity noise region(s). Average reductions in the BVI noise levels on the order of 5 dB with moderate power penalties on the order of 18 pct. for a four bladed rotor and 58 pct. for a two bladed rotor were obtained.

  17. Blade-mounted trailing edge flap control for BVI noise reduction

    NASA Astrophysics Data System (ADS)

    Hassan, A. A.; Charles, B. D.; Tadghighi, H.; Sankar, L. N.

    1992-02-01

    Numerical procedures based on the 2-D and 3-D full potential equations and the 2-D Navier-Stokes equations were developed to study the effects of leading and trailing edge flap motions on the aerodynamics of parallel airfoil-vortex interactions and on the aerodynamics and acoustics of the more general self-generated rotor blade vortex interactions (BVI). For subcritical interactions, the 2-D results indicate that the trailing edge flap can be used to alleviate the impulsive loads experienced by the airfoil. For supercritical interactions, the results show the necessity of using a leading edge flap, rather than a trailing edge flap, to alleviate the interaction. Results for various time dependent flap motions and their effect on the predicted temporal sectional loads, differential pressures, and the free vortex trajectories are presented. For the OLS model rotor, contours of a BVI noise metric were used to quantify the effects of the trailing edge flap on the size and directivity of the high/low intensity noise region(s). Average reductions in the BVI noise levels on the order of 5 dB with moderate power penalties on the order of 18 pct. for a four bladed rotor and 58 pct. for a two bladed rotor were obtained.

  18. Soap Films Burst Like Flapping Flags

    NASA Astrophysics Data System (ADS)

    Lhuissier, Henri; Villermaux, Emmanuel

    2009-07-01

    When punctured, a flat soap film bursts by opening a hole driven by liquid surface tension. The hole rim does not, however, remain smooth but soon develops indentations at the tip of which ligaments form, ultimately breaking and leaving the initially connex film into a mist of disjointed drops. We report on original observations showing that these indentations result from a flaglike instability between the film and the surrounding atmosphere inducing an oscillatory motion out of its plane. Just like a flag edge flaps in the wind, the film is successively accelerated on both sides perpendicularly to its plane, inducing film thickness modulations and centrifuging liquid ligaments that finally pinch off to form the observed spray. This effect exemplifies how the dynamics of fragile objects such as thin liquid films is sensitive to their embedding medium.

  19. PIV Measurements on a Blowing Flap

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Stead, Daniel J.

    2004-01-01

    PIV measurements of the flow in the region of a flap side edge are presented for several blowing flap configurations. The test model is a NACA 63(sub 2)-215 Hicks Mod-B main-element airfoil with a half-span Fowler flap. Air is blown from small slots located along the flap side edge on either the top, bottom or side surfaces. The test set up is described and flow measurements for a baseline and three blowing flap configurations are presented. The effects that the flap tip jets have on the structure of the flap side edge flow are discussed for each of the flap configurations tested. The results indicate that blowing air from a slot located along the top surface of the flap greatly weakened the top vortex system and pushed it further off the top surface. Blowing from the bottom flap surface kept the strong side vortex further outboard while blowing from the side surface only strengthened the vortex system or accelerated the merging of the side vortex to the flap top surface. It is concluded that blowing from the top or bottom surfaces of the flap may lead to a reduction of flap side edge noise.

  20. Predicting muscle activation patterns from motion and anatomy: modelling the skull of Sphenodon (Diapsida: Rhynchocephalia)

    PubMed Central

    Curtis, Neil; Jones, Marc E. H.; Evans, Susan E.; Shi, JunFen; O'Higgins, Paul; Fagan, Michael J.

    2010-01-01

    The relationship between skull shape and the forces generated during feeding is currently under widespread scrutiny and increasingly involves the use of computer simulations such as finite element analysis. The computer models used to represent skulls are often based on computed tomography data and thus are structurally accurate; however, correctly representing muscular loading during food reduction remains a major problem. Here, we present a novel approach for predicting the forces and activation patterns of muscles and muscle groups based on their known anatomical orientation (line of action). The work was carried out for the lizard-like reptile Sphenodon (Rhynchocephalia) using a sophisticated computer-based model and multi-body dynamics analysis. The model suggests that specific muscle groups control specific motions, and that during certain times in the bite cycle some muscles are highly active whereas others are inactive. The predictions of muscle activity closely correspond to data previously recorded from live Sphenodon using electromyography. Apparent exceptions can be explained by variations in food resistance, food size, food position and lower jaw motions. This approach shows considerable promise in advancing detailed functional models of food acquisition and reduction, and for use in other musculoskeletal systems where no experimental determination of muscle activity is possible, such as in rare, endangered or extinct species. PMID:19474084

  1. Modeling meiotic chromosome pairing: nuclear envelope attachment, telomere-led active random motion, and anomalous diffusion

    NASA Astrophysics Data System (ADS)

    Marshall, Wallace F.; Fung, Jennifer C.

    2016-04-01

    The recognition and pairing of homologous chromosomes during meiosis is a complex physical and molecular process involving a combination of polymer dynamics and molecular recognition events. Two highly conserved features of meiotic chromosome behavior are the attachment of telomeres to the nuclear envelope and the active random motion of telomeres driven by their interaction with cytoskeletal motor proteins. Both of these features have been proposed to facilitate the process of homolog pairing, but exactly what role these features play in meiosis remains poorly understood. Here we investigate the roles of active motion and nuclear envelope tethering using a Brownian dynamics simulation in which meiotic chromosomes are represented by a Rouse polymer model subjected to tethering and active forces at the telomeres. We find that tethering telomeres to the nuclear envelope slows down pairing relative to the rates achieved by unattached chromosomes, but that randomly directed active forces applied to the telomeres speed up pairing dramatically in a manner that depends on the statistical properties of the telomere force fluctuations. The increased rate of initial pairing cannot be explained by stretching out of the chromosome conformation but instead seems to correlate with anomalous diffusion of sub-telomeric regions.

  2. Experimental Study of Wake / Flap Interaction Noise and the Reduction of Flap Side Edge Noise

    NASA Technical Reports Server (NTRS)

    Hutcheson, Florence V.; Stead, Daniel J.; Plassman, Gerald E.

    2016-01-01

    The effects of the interaction of a wake with a half-span flap on radiated noise are examined. The incident wake is generated by bars of various widths and lengths or by a simplified landing gear model. Single microphone and phased array measurements are used to isolate the effects of the wake interaction on the noise radiating from the flap side edge and flap cove regions. The effects on noise of the wake generator's geometry and relative placement with respect to the flap are assessed. Placement of the wake generators upstream of the flap side edge is shown to lead to the reduction of flap side edge noise by introducing a velocity deficit and likely altering the instabilities in the flap side edge vortex system. Significant reduction in flap side edge noise is achieved with a bar positioned directly upstream of the flap side edge. The noise reduction benefit is seen to improve with increased bar width, length and proximity to the flap edge. Positioning of the landing gear model upstream of the flap side edge also leads to decreased flap side edge noise. In addition, flap cove noise levels are significantly lower than when the landing gear is positioned upstream of the flap mid-span. The impact of the local flow velocity on the noise radiating directly from the landing gear is discussed. The effects of the landing gear side-braces on flap side edge, flap cove and landing gear noise are shown.

  3. The binding landscape of plasmepsin V and the implications for flap dynamics.

    PubMed

    L, McGillewie; Soliman, Mahmoud E

    2016-04-26

    Plasmepsin V belongs to the plasmepsin family of aspartic proteases. PlmV is unique compared to other plasmepsins, as this membrane bound aspartic protease resides in the endoplasmic reticulum and is responsible for the cleavage of PEXEL tagged proteins destined for export outside of the host red blood cell. Plasmepsin V is highly conserved throughout the Plasmodium species, and is essential to the survival of the parasite. Recently, two potent inhibitors of Plmv have been identified, WEHI-916 and WEHI-842. Of these inhibitors, WEHI-842 has a higher binding affinity for P. vivax PlmV, and a crystal structure of PlmV in complex with WEHI-842 has recently been resolved (). The structure of PlmV is unique compared to other plasmepsins; it is stabilised internally by seven disulfide bonds, a NAP1 insert/fold is associated with the movement of the flap covering the active site and a highly conserved helix-turn-helix is situated towards the C-terminus. Flap motion and dynamics play an important role in enzyme selectivity and function. To better understand the impact of ligand binding on the flap dynamics, molecular dynamic simulations and post-dynamic analysis were employed in the present study on PlmV in complex with WEHI-842. Previously defined parameters, which accurately accounted for the opening and closing of the active site, were used to assess the conformational changes induced in the absence and presence of WEHI-842. From the simulations it can be seen that inhibitor binding significantly reduces the flexibility and mobility of not only the flap and flexible loop but areas outside of the active site. Ligand binding leads to the formation of a more stable compact structure. This being said, there is a possibility of reducing the flexibility even further with potentially more lethal effects on the plasmodium parasite. We believe that results presented herein would assist researchers in the discovery of potent PlmV inhibitors as potential antimalarial therapies

  4. Active breathing control (ABC): Determination and reduction of breathing-induced organ motion in the chest

    SciTech Connect

    Gagel, Bernd . E-mail: BGagel@UKAachen.de; Demirel, Cengiz M.P.; Kientopf, Aline; Pinkawa, Michael; Piroth, Marc; Stanzel, Sven; Breuer, Christian; Asadpour, Branka; Jansen, Thomas; Holy, Richard; Wildberger, Joachim E.; Eble, Michael J.

    2007-03-01

    Purpose: Extensive radiotherapy volumes for tumors of the chest are partly caused by interfractional organ motion. We evaluated the feasibility of respiratory observation tools using the active breathing control (ABC) system and the effect on breathing cycle regularity and reproducibility. Methods and Materials: Thirty-six patients with unresectable tumors of the chest were selected for evaluation of the ABC system. Computed tomography scans were performed at various respiratory phases starting at the same couch position without patient movement. Threshold levels were set at minimum and maximum volume during normal breathing cycles and at a volume defined as shallow breathing, reflecting the subjective maximal tolerable reduction of breath volume. To evaluate the extent of organ movement, 13 landmarks were considering using commercial software for image coregistration. In 4 patients, second examinations were performed during therapy. Results: Investigating the differences in a normal breathing cycle versus shallow breathing, a statistically significant reduction of respiratory motion in the upper, middle, and lower regions of the chest could be detected, representing potential movement reduction achieved through reduced breath volume. Evaluating interfraction reproducibility, the mean displacement ranged between 0.24 mm (chest wall/tracheal bifurcation) to 3.5 mm (diaphragm) for expiration and shallow breathing and 0.24 mm (chest wall) to 5.25 mm (diaphragm) for normal inspiration. Conclusions: By modifying regularity of the respiratory cycle through reduction of breath volume, a significant and reproducible reduction of chest and diaphragm motion is possible, enabling reduction of treatment planning margins.

  5. Processing 3D form and 3D motion: respective contributions of attention-based and stimulus-driven activity.

    PubMed

    Paradis, A-L; Droulez, J; Cornilleau-Pérès, V; Poline, J-B

    2008-12-01

    This study aims at segregating the neural substrate for the 3D-form and 3D-motion attributes in structure-from-motion perception, and at disentangling the stimulus-driven and endogenous-attention-driven processing of these attributes. Attention and stimulus were manipulated independently: participants had to detect the transitions of one attribute--form, 3D motion or colour--while the visual stimulus underwent successive transitions of all attributes. We compared the BOLD activity related to form and 3D motion in three conditions: stimulus-driven processing (unattended transitions), endogenous attentional selection (task) or both stimulus-driven processing and attentional selection (attended transitions). In all conditions, the form versus 3D-motion contrasts revealed a clear dorsal/ventral segregation. However, while the form-related activity is consistent with previously described shape-selective areas, the activity related to 3D motion does not encompass the usual "visual motion" areas, but rather corresponds to a high-level motion system, including IPL and STS areas. Second, we found a dissociation between the neural processing of unattended attributes and that involved in endogenous attentional selection. Areas selective for 3D-motion and form showed either increased activity at transitions of these respective attributes or decreased activity when subjects' attention was directed to a competing attribute. We propose that both facilitatory and suppressive mechanisms of attribute selection are involved depending on the conditions driving this selection. Therefore, attentional selection is not limited to an increased activity in areas processing stimulus properties, and may unveil different functional localization from stimulus modulation.

  6. Development of Kinematic Graphs of Median Nerve during Active Finger Motion: Implications of Smartphone Use

    PubMed Central

    2016-01-01

    Background Certain hand activities cause deformation and displacement of the median nerve at the carpal tunnel due to the gliding motion of tendons surrounding it. As smartphone usage escalates, this raises the public’s concern whether hand activities while using smartphones can lead to median nerve problems. Objective The aims of this study were to 1) develop kinematic graphs and 2) investigate the associated deformation and rotational information of median nerve in the carpal tunnel during hand activities. Methods Dominant wrists of 30 young adults were examined with ultrasonography by placing a transducer transversely on their wrist crease. Ultrasound video clips were recorded when the subject performing 1) thumb opposition with the wrist in neutral position, 2) thumb opposition with the wrist in ulnar deviation and 3) pinch grip with the wrist in neutral position. Six still images that were separated by 0.2-second intervals were then captured from the ultrasound video for the determination of 1) cross-sectional area (CSA), 2) flattening ratio (FR), 3) rotational displacement (RD) and 4) translational displacement (TD) of median nerve in the carpal tunnel, and these collected information of deformation, rotational and displacement of median nerve were compared between 1) two successive time points during a single hand activity and 2) different hand motions at the same time point. Finally, kinematic graphs were constructed to demonstrate the mobility of median nerve during different hand activities. Results Performing different hand activities during this study led to a gradual reduction in CSA of the median nerve, with thumb opposition together with the wrist in ulnar deviation causing the greatest extent of deformation of the median nerve. Thumb opposition with the wrist in ulnar deviation also led to the largest extent of TD when compared to the other two hand activities of this study. Kinematic graphs showed that the motion pathways of median nerve during

  7. Respiratory Motion of The Heart and Positional Reproducibility Under Active Breathing Control

    SciTech Connect

    Jagsi, Reshma; Moran, Jean M.; Kessler, Marc L.; Marsh, Robin B. C; Balter, James M.; Pierce, Lori J. . E-mail: ljpierce@umich.edu

    2007-05-01

    Purpose: To reduce cardiotoxicity from breast radiotherapy (RT), innovative techniques are under investigation. Information about cardiac motion with respiration and positional reproducibility under active breathing control (ABC) is necessary to evaluate these techniques. Methods and Materials: Patients requiring loco-regional RT for breast cancer were scanned by computed tomography using an ABC device at various breath-hold states, before and during treatment. Ten patients were studied. For each patient, 12 datasets were analyzed. Mutual information-based regional rigid alignment was used to determine the magnitude and reproducibility of cardiac motion as a function of breathing state. For each scan session, motion was quantified by evaluating the displacement of a point along the left anterior descending artery (LAD) with respect to its position at end expiration. Long-term positional reproducibility was also assessed. Results: Displacement of the LAD was greatest in the inferior direction, moderate in the anterior direction, and lowest in the left-right direction. At shallow breathing states, the average displacement of LAD position was up to 6 mm in the inferior direction. The maximum displacement in any patient was 2.8 cm in the inferior direction, between expiration and deep-inspiration breath hold. At end expiration, the long-term reproducibility (SD) of the LAD position was 3 mm in the A-P, 6 mm in the S-I, and 4 mm in the L-R directions. At deep-inspiration breath hold, long-term reproducibility was 3 mm in the A-P, 7 mm in the S-I, and 3 mm in the L-R directions. Conclusions: These data demonstrate the extent of LAD displacement that occurs with shallow breathing and with deep-inspiration breath hold. This information may guide optimization studies considering the effects of respiratory motion and reproducibility of cardiac position on cardiac dose, both with and without ABC.

  8. Beneficial Effects of Aminoguanidine on Skin Flap Survival in Diabetic Rats

    PubMed Central

    Ozturk, Ayse; Fırat, Cemal; Parlakpınar, Hakan; Bay-Karabulut, Aysun; Kirimlioglu, Hale; Gurlek, Ali

    2012-01-01

    Random flaps in DM patients have poor reliability for wound coverage, and flap loss remains a complex challenge. The protective effects of aminoguanidine (AG) administration on the survival of dorsal random flaps and oxidative stress were studied in diabetic rats. Two months after the onset of DM, dorsal McFarlane flaps were raised. Forty rats were divided into four groups: (1) control, (2) AG, (3) DM, and (4) DM + AG groups. Flap viability, determined with the planimetric method, and free-radical measurements were investigated. In addition, HbA1c and blood glucose levels, body weight measurements, and histopathological examinations were evaluated. The mean flap necrotic areas (%) in Groups I to IV were 50.9 ± 13.0, 32.9 ± 12.5, 65.2 ± 11.5, and 43.5 ± 14.7, respectively. The malondialdehyde (MDA) and nitric oxide (NO) levels were higher in the DM group than in the nondiabetic group, while the reduced glutathione (GSH) levels and superoxide dismutase (SOD) activity were reduced as a result of flap injury. In the diabetic and nondiabetic groups, AG administration significantly reduced the MDA and NO levels and significantly increased GSH content and SOD enzyme activity. We concluded that AG plays an important role in preventing random pattern flap necrosis. PMID:23304118

  9. Relationships between Paraspinal Muscle Activity and Lumbar Inter-Vertebral Range of Motion.

    PubMed

    du Rose, Alister; Breen, Alan

    2016-01-01

    Control of the lumbar spine requires contributions from both the active and passive sub-systems. Identifying interactions between these systems may provide insight into the mechanisms of low back pain. However, as a first step it is important to investigate what is normal. The purpose of this study was to explore the relationships between the lumbar inter-vertebral range of motion and paraspinal muscle activity during weight-bearing flexion in healthy controls using quantitative fluoroscopy (QF) and surface electromyography (sEMG). Contemporaneous lumbar sEMG and QF motion sequences were recorded during controlled active flexion of 60° using electrodes placed over Longissimus thoracis pars thoracis (TES), Longissimus thoracis pars lumborum (LES), and Multifidus (LMU). Normalised root mean square (RMS) sEMG amplitude data were averaged over five epochs, and the change in amplitude between epochs was calculated. The sEMG ratios of LMU/LES LMU/TES and LES/TES were also determined. QF was used to measure the maximum inter-vertebral range of motion from L2-S1, and correlation coefficients were calculated between sEMG amplitude variables and these measurements. Intra- and inter-session sEMG amplitude repeatability was also assessed for all three paraspinal muscles. The sEMG amplitude measurements were highly repeatable, and sEMG amplitude changes correlated significantly with L4-5 and L5-S1 IV-RoMmax (r = -0.47 to 0.59). The sEMG amplitude ratio of LES/TES also correlated with L4-L5 IV-RoMmax (r = -0.53). The relationships found may be important when considering rehabilitation for low back pain. PMID:27417592

  10. Relationships between Paraspinal Muscle Activity and Lumbar Inter-Vertebral Range of Motion

    PubMed Central

    du Rose, Alister; Breen, Alan

    2016-01-01

    Control of the lumbar spine requires contributions from both the active and passive sub-systems. Identifying interactions between these systems may provide insight into the mechanisms of low back pain. However, as a first step it is important to investigate what is normal. The purpose of this study was to explore the relationships between the lumbar inter-vertebral range of motion and paraspinal muscle activity during weight-bearing flexion in healthy controls using quantitative fluoroscopy (QF) and surface electromyography (sEMG). Contemporaneous lumbar sEMG and QF motion sequences were recorded during controlled active flexion of 60° using electrodes placed over Longissimus thoracis pars thoracis (TES), Longissimus thoracis pars lumborum (LES), and Multifidus (LMU). Normalised root mean square (RMS) sEMG amplitude data were averaged over five epochs, and the change in amplitude between epochs was calculated. The sEMG ratios of LMU/LES LMU/TES and LES/TES were also determined. QF was used to measure the maximum inter-vertebral range of motion from L2-S1, and correlation coefficients were calculated between sEMG amplitude variables and these measurements. Intra- and inter-session sEMG amplitude repeatability was also assessed for all three paraspinal muscles. The sEMG amplitude measurements were highly repeatable, and sEMG amplitude changes correlated significantly with L4-5 and L5-S1 IV-RoMmax (r = −0.47 to 0.59). The sEMG amplitude ratio of LES/TES also correlated with L4-L5 IV-RoMmax (r = −0.53). The relationships found may be important when considering rehabilitation for low back pain. PMID:27417592

  11. Effects of calcitriol on random skin flap survival in rats

    PubMed Central

    Zhou, Kai-liang; Zhang, Yi-hui; Lin, Ding-sheng; Tao, Xian-yao; Xu, Hua-zi

    2016-01-01

    Calcitriol, a metabolite of vitamin D, is often used in osteoporosis clinics. However, the material has other bioactivities; for example, it accelerates angiogenesis, has anti-inflammatory properties, and inhibits oxidative stress. We investigated the effects of calcitriol in a random skin flap rat model. “McFarlane flap” models were established in 84 male Sprague Dawley rats, divided into two groups. One group received intraperitoneal injections of calcitriol (2 μg/kg/day) whereas control rats received intraperitoneal injections of saline. The percentage flap survival area and tissue water content were measured 7 days later, which showed that calcitriol improved flap survival area and reduced tissue edema. It also increased the mean vessel density and upregulated levels of VEGF mRNA/protein, both of which promote flap angiogenesis. Moreover, it decreased leukocyte and macrophage infiltration, reduced the inflammatory proteins IL1β and IL6, increased SOD activity, decreased MDA content, and upregulated the level of autophagy. Overall, our results suggest that calcitriol promotes skin flap survival by accelerating angiogenesis, having anti-inflammatory effects, reducing oxidative stress, and promoting autophagy. PMID:26732750

  12. Extract the Relational Information of Static Features and Motion Features for Human Activities Recognition in Videos

    PubMed Central

    2016-01-01

    Both static features and motion features have shown promising performance in human activities recognition task. However, the information included in these features is insufficient for complex human activities. In this paper, we propose extracting relational information of static features and motion features for human activities recognition. The videos are represented by a classical Bag-of-Word (BoW) model which is useful in many works. To get a compact and discriminative codebook with small dimension, we employ the divisive algorithm based on KL-divergence to reconstruct the codebook. After that, to further capture strong relational information, we construct a bipartite graph to model the relationship between words of different feature set. Then we use a k-way partition to create a new codebook in which similar words are getting together. With this new codebook, videos can be represented by a new BoW vector with strong relational information. Moreover, we propose a method to compute new clusters from the divisive algorithm's projective function. We test our work on the several datasets and obtain very promising results. PMID:27656199

  13. Extract the Relational Information of Static Features and Motion Features for Human Activities Recognition in Videos

    PubMed Central

    2016-01-01

    Both static features and motion features have shown promising performance in human activities recognition task. However, the information included in these features is insufficient for complex human activities. In this paper, we propose extracting relational information of static features and motion features for human activities recognition. The videos are represented by a classical Bag-of-Word (BoW) model which is useful in many works. To get a compact and discriminative codebook with small dimension, we employ the divisive algorithm based on KL-divergence to reconstruct the codebook. After that, to further capture strong relational information, we construct a bipartite graph to model the relationship between words of different feature set. Then we use a k-way partition to create a new codebook in which similar words are getting together. With this new codebook, videos can be represented by a new BoW vector with strong relational information. Moreover, we propose a method to compute new clusters from the divisive algorithm's projective function. We test our work on the several datasets and obtain very promising results.

  14. New model of flap-gliding flight.

    PubMed

    Sachs, Gottfried

    2015-07-21

    A new modelling approach is presented for describing flap-gliding flight in birds and the associated mechanical energy cost of travelling. The new approach is based on the difference in the drag characteristics between flapping and non-flapping due to the drag increase caused by flapping. Thus, the possibility of a gliding flight phase, as it exists in flap-gliding flight, yields a performance advantage resulting from the decrease in the drag when compared with continuous flapping flight. Introducing an appropriate non-dimensionalization for the mathematical relations describing flap-gliding flight, results and findings of generally valid nature are derived. It is shown that there is an energy saving of flap-gliding flight in the entire speed range compared to continuous flapping flight. The energy saving reaches the highest level in the lower speed region. The travelling speed of flap-gliding flight is composed of the weighted average of the differing speeds in the flapping and gliding phases. Furthermore, the maximum range performance achievable with flap-gliding flight and the associated optimal travelling speed are determined.

  15. Kinematics of flap-bounding flight in the zebra finch over a wide range of speeds

    PubMed

    Tobalske; Peacock; Dial

    1999-07-01

    It has been proposed elsewhere that flap-bounding, an intermittent flight style consisting of flapping phases interspersed with flexed-wing bounds, should offer no savings in average mechanical power relative to continuous flapping unless a bird flies 1.2 times faster than its maximum range speed (Vmr). Why do some species use intermittent bounds at speeds slower than 1.2Vmr? The 'fixed-gear hypothesis' suggests that flap-bounding is used to vary mean power output in small birds that are otherwise constrained by muscle physiology and wing anatomy to use a fixed muscle shortening velocity and pattern of wing motion at all flight speeds; the 'body-lift hypothesis' suggests that some weight support during bounds could make flap-bounding flight aerodynamically advantageous in comparison with continuous flapping over most forward flight speeds. To test these predictions, we studied high-speed film recordings (300 Hz) of wing and body motion in zebra finches (Taenopygia guttata, mean mass 13.2 g, N=4) taken as the birds flew in a variable-speed wind tunnel (0-14 m s-1). The zebra finches used flap-bounding flight at all speeds, so their flight style was unique compared with that of birds that facultatively shift from continuous flapping or flap-gliding at slow speeds to flap-bounding at fast speeds. There was a significant effect of flight speed on all measured aspects of wing motion except percentage of the wingbeat spent in downstroke. Changes in angular velocity of the wing indicated that contractile velocity in the pectoralis muscle changed with flight speed, which is not consistent with the fixed-gear hypothesis. Although variation in stroke-plane angle relative to the body, pronation angle of the wing and wing span at mid-upstroke showed that the zebra finch changed within-wingbeat geometries according to speed, a vortex-ring gait with a feathered upstroke appeared to be the only gait used during flapping. In contrast, two small species that use continuous flapping

  16. Evidence That the DNA Mismatch Repair System Removes 1-Nucleotide Okazaki Fragment Flaps*♦

    PubMed Central

    Kadyrova, Lyudmila Y.; Dahal, Basanta K.; Kadyrov, Farid A.

    2015-01-01

    The DNA mismatch repair (MMR) system plays a major role in promoting genome stability and suppressing carcinogenesis. In this work, we investigated whether the MMR system is involved in Okazaki fragment maturation. We found that in the yeast Saccharomyces cerevisiae, the MMR system and the flap endonuclease Rad27 act in overlapping pathways that protect the nuclear genome from 1-bp insertions. In addition, we determined that purified yeast and human MutSα proteins recognize 1-nucleotide DNA and RNA flaps. In reconstituted human systems, MutSα, proliferating cell nuclear antigen, and replication factor C activate MutLα endonuclease to remove the flaps. ATPase and endonuclease mutants of MutLα are defective in the flap removal. These results suggest that the MMR system contributes to the removal of 1-nucleotide Okazaki fragment flaps. PMID:26224637

  17. Deep digital burns treated with 2 abdominal flaps: case report.

    PubMed

    Wu, Choulang; Zhou, Lichun; Zhu, Lili; Zheng, Jinman

    2013-11-01

    We present the case of a 22-year-old man with third- to fourth-degree flame burns to all fingers of the right hand. After removing the necrotic tissues and amputating the carbonized distal segments of each finger, we covered the injured thumb with a paraumbilical tubular flap and covered the other fingers with an abdominal wall marsupial flap. Fifty days after injury, all the wounds healed, and the remaining fingers were salvaged. Four months after injury, the grip strength and the first web span of the right hand was 23.6 kg and 53°, and the patient could fulfill almost all the activities of daily living.

  18. Development of a Wind Turbine Test Rig and Rotor for Trailing Edge Flap Investigation: Static Flap Angles Case

    NASA Astrophysics Data System (ADS)

    Abdelrahman, Ahmed; Johnson, David A.

    2014-06-01

    One of the strategies used to improve performance and increase the life-span of wind turbines is active flow control. It involves the modification of the aerodynamic characteristics of a wind turbine blade by means of moveable aerodynamic control surfaces. Trailing edge flaps are relatively small moveable control surfaces placed at the trailing edge of a blade's airfoil that modify the lift of a blade or airfoil section. An instrumented wind turbine test rig and rotor were specifically developed to enable a wide-range of experiments to investigate the potential of trailing edge flaps as an active control technique. A modular blade based on the S833 airfoil was designed to allow accurate instrumentation and customizable settings. The blade is 1.7 meters long, had a constant 178mm chord and a 6° pitch. The modular aerodynamic parts were 3D printed using plastic PC-ABS material. The blade design point was within the range of wind velocities in the available large test facility. The wind facility is a large open jet wind tunnel with a maximum velocity of 11m/s in the test area. The capability of the developed system was demonstrated through an initial study of the effect of stationary trailing edge flaps on blade load and performance. The investigation focused on measuring the changes in flapwise bending moment and power production for different trailing edge flap spanwise locations and deflection angles. The relationship between the load reduction and deflection angle was linear as expected from theory and the highest reduction was caused by the flap furthest from the rotor center. Overall, the experimental setup proved to be effective in measuring small changes in flapwise bending moment within the wind turbine blade and will provide insight when (active) flap control is targeted.

  19. Semi-active control of the rocking motion of monolithic art objects

    NASA Astrophysics Data System (ADS)

    Ceravolo, Rosario; Pecorelli, Marica Leonarda; Zanotti Fragonara, Luca

    2016-07-01

    The seismic behaviour of many art objects and obelisks can be analysed in the context of the seismic response of rigid blocks. Starting from the pioneering works by Housner, a large number of analytical studies of the rigid block dynamics were proposed. In fact, despite its apparent simplicity, the motion of a rigid block involves a number of complex dynamic phenomena such as impacts, sliding, uplift and geometric nonlinearities. While most of the current strategies to avoid toppling consist in preventing rocking motion, in this paper a novel semi-active on-off control strategy for protecting monolithic art objects was investigated. The control procedure under study follows a feedback-feedforward scheme that is realised by switching the stiffness of the anchorages located at the two lower corner of the block between two values. Overturning spectra have been calculated in order to clarify the benefits of applying a semi-active control instead of a passive control strategy. In accordance with similar studies, the numerical investigation took into account the dynamic response of blocks with different slenderness and size subject to one-sine pulse excitation.

  20. Reliability of the universal goniometer for assessing active cervical range of motion in asymptomatic healthy persons

    PubMed Central

    Farooq, Muhammad Nazim; Bandpei, Mohammad A. Mohseni; Ali, Mudassar; Khan, Ghazanfar Ali

    2016-01-01

    Objective: To determine within-rater and between-rater reliability of the universal goniometer (UG) for measuring active cervical range of motion (ACROM) in asymptomatic healthy subjects. Methods: Nineteen healthy subjects were tested in an identical seated position. Two raters used UG to measure active cervical movements of flexion, extension, right side flexion, left side flexion, right rotation and left rotation. Each motion was measured twice by each of the two raters and was re-measured all over again after one week. Data analysis was performed using the intraclass correlation coefficient (ICC). Results: The results demonstrated excellent within-session (ICC2,1 = 0.83 to 0.98) and between-session (ICC2,2 = 0.79 to 0.97) intra-rater reliability and excellent inter-rater reliability (ICC2,2 = 0.79 to 0.92). Conclusion: Considering above results it is concluded that UG is a reliable tool for assessing ACROM in a clinical setting for healthy subjects. PMID:27182261

  1. Flow structures around a flapping wing considering ground effect

    NASA Astrophysics Data System (ADS)

    Van Truong, Tien; Kim, Jihoon; Kim, Min Jun; Park, Hoon Cheol; Yoon, Kwang Joon; Byun, Doyoung

    2013-07-01

    Over the past several decades, there has been great interest in understanding the aerodynamics of flapping flight, namely the two flight modes of hovering and forward flight. However, there has been little focus on the aerodynamic characteristics during takeoff of insects. In a previous study we found that the Rhinoceros Beetle ( Trypoxylusdichotomus) takes off without jumping, which is uncommon for other insects. In this study we built a scaled-up electromechanical model of a flapping wing and investigated fluid flow around the beetle's wing model. In particular, the present dynamically scaled mechanical model has the wing kinematics pattern achieved from the real beetle's wing kinematics during takeoff. In addition, we could systematically change the three-dimensional inclined motion of the flapping model through each stroke. We used digital particle image velocimetry with high spatial resolution, and were able to qualitatively and quantitatively study the flow field around the wing at a Reynolds number of approximately 10,000. The present results provide insight into the aerodynamics and the evolution of vortical structures, as well as the ground effect experienced by a beetle's wing during takeoff. The main unsteady mechanisms of beetles have been identified and intensively analyzed as the stability of the leading edge vortex (LEV) during strokes, the delayed stall during upstroke, the rotational circulation in pronation periods, and wake capture in supination periods. Due to the ground effect, the LEV was enhanced during half downstroke, and the lift force could thus be increased to lift the beetle during takeoff. This is useful for researchers in developing a micro air vehicle that has a beetle-like flapping wing motion.

  2. Active and passive Brownian motion of charged particles in two-dimensional plasma models

    SciTech Connect

    Dunkel, Joern; Ebeling, Werner; Trigger, Sergey A.

    2004-10-01

    The dynamics of charged Coulomb grains in a plasma is numerically and analytically investigated. Analogous to recent experiments, it is assumed that the grains are trapped in an external parabolic field. Our simulations are based on a Langevin model, where the grain-plasma interaction is realized by a velocity-dependent friction coefficient and a velocity-independent diffusion coefficient. In addition to the ordinary case of positive (passive) friction between grains and plasma, we also discuss the effects of negative (active) friction. The latter case seems particularly interesting, since recent analytical calculations have shown that friction coefficients with negative parts may appear in some models of ion absorption by grains as well as in models of ion-grain scattering. Such negative friction may cause active Brownian motions of the grains. As our computer simulations show, the influence of negative friction leads to the formation of various stationary modes (rotations, oscillations), which, to some extent, can also be estimated analytically.

  3. The roles of aerodynamic and inertial forces on maneuverability in flapping flight

    NASA Astrophysics Data System (ADS)

    Vejdani, Hamid; Boerma, David; Swartz, Sharon; Breuer, Kenneth

    2015-11-01

    We investigate the relative contributions of aerodynamic and the whole-body dynamics in generating extreme maneuvers. We developed a 3D dynamical model of a body (trunk) and two rectangular wings using a Lagrangian formulation. The trunk has 6 degrees of freedom and each wing has 4 degrees of actuation (flapping, sweeping, wing pronation/supination and wing extension/flexion) and can be massless (like insect wings) or relatively massive (like bats). To estimate aerodynamic forces, we use a blade element method; drag and lift are calculated using a quasi-steady model. We validated our model using several benchmark tests, including gliding and hovering motion. To understand the roles of aerodynamic and inertial forces, we start the investigation by constraining the wing motion to flapping and wing length extension/flexion motion. This decouples the trunk degrees of freedom and affects only roll motion. For bats' dynamics (massive wings), the model is much more maneuverable than the insect dynamics case, and the effect of inertial forces dominates the behavior of the system. The role of the aerodynamic forces increases when the wings have sweeping and flapping motion, which affects the pitching motion of the body. We also analyzed the effect of all wing motions together on the behavior of the model in the presence and in the absence of aerodynamic forces.

  4. Flap/Lag/Torsion Dynamics of a Uniform, Cantilever Rotor Blade in Hover

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1977-01-01

    The dynamic stability of the flap/lag/torsion motion of a uniform, cantilever rotor blade in hover is calculated. The influence of blade collective pitch, lag frequency, torsional flexibility, structural coupling, and precone angle on the stability is examined. Good agreement is found with the results of an independent analytical investigation.

  5. Sternocleidomastoid Muscle Flap after Parotidectomy

    PubMed Central

    Nofal, Ahmad Abdel-Fattah; Mohamed, Morsi

    2015-01-01

    Introduction Most patients after either superficial or total parotidectomy develop facial deformity and Frey syndrome, which leads to a significant degree of patient dissatisfaction. Objective Assess the functional outcome and esthetic results of the superiorly based sternocleidomastoid muscle (SCM) flap after superficial or total parotidectomy. Methods A prospective cohort study for 11 patients subjected to parotidectomy using a partial-thickness superiorly based SCM flap. The functional outcome (Frey syndrome, facial nerve involvement, and ear lobule sensation) and the esthetic results were evaluated subjectively and objectively. Results Facial nerve palsy occurred in 5 cases (45%), and all of them recovered completely within 6 months. The Minor starch iodine test was positive in 3 patients (27%), although only 1 (9%) subjectively complained of gustatory sweating. The designed visual analog score completed by the patients themselves ranged from 0 to 3 with a mean of 1.55 ± 0.93; the scores from the blinded evaluators ranged from 1 to 3 with a mean 1.64 ± 0.67. Conclusion The partial-thickness superiorly based SCM flap offers a reasonable cosmetic option for reconstruction following either superficial or total parotidectomy by improving the facial deformity. The flap also lowers the incidence of Frey syndrome objectively and subjectively with no reported hazard of the spinal accessory nerve. PMID:26491478

  6. Thermal and Kinetic Properties of Motions in a Prominence Activation and Nearby Loop

    NASA Technical Reports Server (NTRS)

    Kucera, Therese; Landi, E.

    2005-01-01

    We perform a quantitative analysis of the thermal properties of a prominence activation and motions in a nearby loop. In order to make measurements of the quickly moving features seen in prominences in the UV we use the SOHO/SUMER spectrograph to take a time series of exposures from a single pointing position, providing a measurement of spectral line properties as a function of time and position along the slit. The lines observed cover a broad range of temperatures from 80,000 - 1.6 million K. These measurements are combined with TRACE movies in transition region and coronal temperature bands to obtain more complete information concerning prominence structure and motions. The resulting observations allow us to analyze the thermal and kinetic energy of the moving sources as functions of time. The loop and prominence are most apparent in lines formed at temperatures below 250,000 K. We find that in most cases the temperature distribution of plasma in a moving feature changes relatively little over time periods of about 20 minutes.

  7. The feasibility of shoulder motion tracking during activities of daily living using inertial measurement units.

    PubMed

    Kirking, Bryan; El-Gohary, Mahmoud; Kwon, Young

    2016-09-01

    Measurements of shoulder kinematics during activities of daily living (ADL) can be used to evaluate patient function before and after treatment and help define device testing conditions. The purpose of this study was to demonstrate the feasibility of using wearable inertial measurement units (IMUs) to track shoulder joint angles while performing actual ADLs outside of laboratory simulations. IMU data of 5 subjects with normal shoulders was collected for 4h at the subjects' workplace and up to 4h off-work. An Unscented Kalman Filter (UKF) enhanced with gyroscope bias modeling and zero velocity updates demonstrated an accuracy of about 2° and was used to estimate relative upper arm angles from the IMU data. The overall averaged 95th percentile angles were: flexion 128.8°, abduction 128.4°, and external rotation 69.5°. These peaks angles are similar to other investigator's reports using laboratory simulations of ADLs measured with optical and electromagnetic technologies. Additionally, with a Fourier transform the 50th percentile frequency was determined and used to extrapolate the typical number of arm cycles in a 10year period to be 649,000. Application of the UKF with the additional drift correction made substantial improvements in shoulder tracking performance and this feasibility data suggests that IMUs with the UKF are suitable for extended use outside of laboratory settings. The data provides a novel description of arm motion during ADLs including an estimate for the 10 year cycle count of upper arm motion. PMID:27371783

  8. Development of magnetically preloaded air bearings for a linear slide: active compensation of three degrees of freedom motion errors.

    PubMed

    Ro, Seung-Kook; Kim, Soohyun; Kwak, Yoonkeun; Park, Chun-Hong

    2008-03-01

    This article describes a linear air-bearing stage that uses active control to compensate for its motion errors. The active control is based on preloads generated by magnetic actuators, which were designed to generate nominal preloads for the air bearings using permanent magnets to maintain the desired stiffness while changing the air-bearing clearance by varying the magnetic flux generated by the current in electromagnetic coils. A single-axis linear stage with a linear motor and 240 mm of travel range was built to verify this design concept and used to test its performance. The motion of the table in three directions was controlled with four magnetic actuators driven by current amplifiers and a DSP (Digital Signal Processor)-based digital controller. The motion errors were measured using a laser interferometer combined with a two-probe method, and had 0.085 microm of repeatability for the straightness error. As a result of feed-forward active compensation, the errors were reduced from 1.09 to 0.11 microm for the vertical motion, from 9.42 to 0.18 arcsec for the pitch motion, and from 2.42 to 0.18 arcsec for the roll motion. PMID:18377049

  9. A new twist on gyroscopic sensing: body rotations lead to torsion in flapping, flexing insect wings

    PubMed Central

    Eberle, A. L.; Dickerson, B. H.; Reinhall, P. G.; Daniel, T. L.

    2015-01-01

    Insects perform fast rotational manoeuvres during flight. While two insect orders use flapping halteres (specialized organs evolved from wings) to detect body dynamics, it is unknown how other insects detect rotational motions. Like halteres, insect wings experience gyroscopic forces when they are flapped and rotated and recent evidence suggests that wings might indeed mediate reflexes to body rotations. But, can gyroscopic forces be detected using only changes in the structural dynamics of a flapping, flexing insect wing? We built computational and robotic models to rotate a flapping wing about an axis orthogonal to flapping. We recorded high-speed video of the model wing, which had a flexural stiffness similar to the wing of the Manduca sexta hawkmoth, while flapping it at the wingbeat frequency of Manduca (25 Hz). We compared the three-dimensional structural dynamics of the wing with and without a 3 Hz, 10° rotation about the yaw axis. Our computational model revealed that body rotation induces a new dynamic mode: torsion. We verified our result by measuring wing tip displacement, shear strain and normal strain of the robotic wing. The strains we observed could stimulate an insect's mechanoreceptors and trigger reflexive responses to body rotations. PMID:25631565

  10. Free thin anterolateral thigh flap for post-burn neck contractures - a functional and aesthetic solution.

    PubMed

    Sarkar, A; Raghavendra, S; Jeelani Naiyer, M G; Bhattacharya, D; Dutta, G; Bain, J; Asha, J

    2014-12-31

    Neck contractures after burn injuries produce restrictions in motion and unacceptable aesthetic outcomes. Although different methods of reconstruction have been used in the treatment of this ailment, a limited and unsatisfactory outcome often results. Free thin anterolateral flaps have been found to be a good single stage option for reconstruction of post-burn contractures of the neck. In our study, 11 patients with post flame burn contractures of the neck underwent surgical release and coverage by a free thin anterolateral thigh flap. Patients were followed up for an average of five years and various aspects of functional and aesthetic rehabilitation were assessed. Our findings revealed that the free thin anterolateral flaps covered the defects over anterior and lateral aspects of the neck with good colour match and contour. Furthermore, none of the flaps had any significant early or delayed complications. Two cases had to be reoperated for partial loss of flaps and all patients were satisfied with functional and aesthetic outcomes. We therefore consider free thin anterolateral thigh flaps to provide a good single stage reconstruction for post-burn cervical contractures with good functional and aesthetic outcomes.

  11. Multi-digit contracture release using medial sural artery perforator flap with syndactylization-desyndactylization method

    PubMed Central

    Eren, F; Oksuz, S; Karagöz, H; Melikoğlu, C; Ulkur, E

    2015-01-01

    Background: The medial sural artery perforator flap, with a long pedicle, has tremendous potential for applications in a variety of soft tissue defects. It can be used for reconstruction of multi-digit contractures of the palmar region. Materials and Methods: We present herein the key features of the management of postburn multi-digit volar contractures, using medial sural artery perforator flaps with the syndactylization and desyndactylization method. We describe the use of the free medial sural artery perforator flap in two patients, to reconstruct complex composite hand defects including the second, third, fourth and fifth digits following thermal burns. Results: Both flaps healed uneventfully. In both patients, the hand contractures released completely and adequate joint motion was achieved after a 3-month period of physiotherapy. Conclusions: The thin medial sural artery perforator flap permits high accuracy of soft tissue reconstruction of the hand and reduces the morbidity at the donor site. The MSAPF is a useful flap in areas such as the hands, in the case of soft tissue deficiency and tendon exposition. Hippokratia 2015; 19 (4): 366-368.

  12. A new twist on gyroscopic sensing: body rotations lead to torsion in flapping, flexing insect wings.

    PubMed

    Eberle, A L; Dickerson, B H; Reinhall, P G; Daniel, T L

    2015-03-01

    Insects perform fast rotational manoeuvres during flight. While two insect orders use flapping halteres (specialized organs evolved from wings) to detect body dynamics, it is unknown how other insects detect rotational motions. Like halteres, insect wings experience gyroscopic forces when they are flapped and rotated and recent evidence suggests that wings might indeed mediate reflexes to body rotations. But, can gyroscopic forces be detected using only changes in the structural dynamics of a flapping, flexing insect wing? We built computational and robotic models to rotate a flapping wing about an axis orthogonal to flapping. We recorded high-speed video of the model wing, which had a flexural stiffness similar to the wing of the Manduca sexta hawkmoth, while flapping it at the wingbeat frequency of Manduca (25 Hz). We compared the three-dimensional structural dynamics of the wing with and without a 3 Hz, 10° rotation about the yaw axis. Our computational model revealed that body rotation induces a new dynamic mode: torsion. We verified our result by measuring wing tip displacement, shear strain and normal strain of the robotic wing. The strains we observed could stimulate an insect's mechanoreceptors and trigger reflexive responses to body rotations.

  13. Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance.

    PubMed

    Ramananarivo, Sophie; Godoy-Diana, Ramiro; Thiria, Benjamin

    2011-04-12

    Saving energy and enhancing performance are secular preoccupations shared by both nature and human beings. In animal locomotion, flapping flyers or swimmers rely on the flexibility of their wings or body to passively increase their efficiency using an appropriate cycle of storing and releasing elastic energy. Despite the convergence of many observations pointing out this feature, the underlying mechanisms explaining how the elastic nature of the wings is related to propulsive efficiency remain unclear. Here we use an experiment with a self-propelled simplified insect model allowing to show how wing compliance governs the performance of flapping flyers. Reducing the description of the flapping wing to a forced oscillator model, we pinpoint different nonlinear effects that can account for the observed behavior--in particular a set of cubic nonlinearities coming from the clamped-free beam equation used to model the wing and a quadratic damping term representing the fluid drag associated to the fast flapping motion. In contrast to what has been repeatedly suggested in the literature, we show that flapping flyers optimize their performance not by especially looking for resonance to achieve larger flapping amplitudes with less effort, but by tuning the temporal evolution of the wing shape (i.e., the phase dynamics in the oscillator model) to optimize the aerodynamics. PMID:21444774

  14. Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance.

    PubMed

    Ramananarivo, Sophie; Godoy-Diana, Ramiro; Thiria, Benjamin

    2011-04-12

    Saving energy and enhancing performance are secular preoccupations shared by both nature and human beings. In animal locomotion, flapping flyers or swimmers rely on the flexibility of their wings or body to passively increase their efficiency using an appropriate cycle of storing and releasing elastic energy. Despite the convergence of many observations pointing out this feature, the underlying mechanisms explaining how the elastic nature of the wings is related to propulsive efficiency remain unclear. Here we use an experiment with a self-propelled simplified insect model allowing to show how wing compliance governs the performance of flapping flyers. Reducing the description of the flapping wing to a forced oscillator model, we pinpoint different nonlinear effects that can account for the observed behavior--in particular a set of cubic nonlinearities coming from the clamped-free beam equation used to model the wing and a quadratic damping term representing the fluid drag associated to the fast flapping motion. In contrast to what has been repeatedly suggested in the literature, we show that flapping flyers optimize their performance not by especially looking for resonance to achieve larger flapping amplitudes with less effort, but by tuning the temporal evolution of the wing shape (i.e., the phase dynamics in the oscillator model) to optimize the aerodynamics.

  15. Control of a Virtual Vehicle Influences Postural Activity and Motion Sickness

    ERIC Educational Resources Information Center

    Dong, Xiao; Yoshida, Ken; Stoffregen, Thomas A.

    2011-01-01

    Everyday experience suggests that drivers are less susceptible to motion sickness than passengers. In the context of inertial motion (i.e., physical displacement), this effect has been confirmed in laboratory research using whole body motion devices. We asked whether a similar effect would occur in the context of simulated vehicles in a visual…

  16. A new agent for flap survival - Hippophae rhamnoides L. (sea buckthorn): An experimental study in rats.

    PubMed

    Emsen, Ilteris Murat

    2005-01-01

    Hippophae rhamnoides L. (sea buckthorn) is a member of the Elaeagnaceae family, and is a temperate bush native to Europe and Asia. The antioxidant activity of H rhamnoides L. has been shown in vitro cell culture and animal studies. Different fractions of H rhamnoides L. fruits inhibit 2,2-azobis-(2,4 dimethylvaleronitrile) and ascorbate iron-induced lipid peroxidations in vitro. H rhamnoides L., as well as vitamin E, decrease the malondialdehyde content in hyperlipidemic rabbit serum-cultured smooth muscle cells. The aim of the present study was to investigate, in a rat model, the potential effect of H rhamnoides L. on survival of random pattern skin flaps. For this purpose, 30 Wistar Albino rats were used, and a McFarlane-type caudally based skin flap was created on the dorsum of the rat (2.5 cm × 8 cm). Rats were divided into three groups: one control (group A) and two treatment groups (groups B and C). H rhamnoides L. was administered orally to the experimental groups: group B received a single 15 mg/kg dose per day and group C received 15 mg/kg twice per day. The areas and lengths of flap necrosis were measured in each group. The extent of necrotic flap areas were evaluated as length and area of total flap area, and differences were studied by Student's t tests. The areas and lengths of necrosis of skin flaps decreased depending on H rhamnoides L., but viability of the flaps treated with 15 mg/kg/day was not significantly different from the control group. The rats receiving H rhamnoides L. 15 mg/kg twice per day had the highest flap survival rate (P<0.001). In conclusion, H rhamnoides L. may have a dose-dependent effect to increase flap survival in random skin flaps. PMID:24227931

  17. The possibility for use of venous flaps in plastic surgery

    NASA Astrophysics Data System (ADS)

    Baytinger, V. F.; Kurochkina, O. S.; Selianinov, K. V.; Baytinger, A. V.; Dzyuman, A. N.

    2015-11-01

    The use of venous flaps is controversial. The mechanism of perfusion of venous flaps is still not fully understood. The research was conducted on 56 white rats. In our experimental work we studied two different models of venous flaps: pedicled venous flap (PVF) and pedicled arterialized venous flap (PAVF). Our results showed that postoperative congestion was present in all flaps. However 66.7% of all pedicled venous flaps and 100% of all pedicled arterialized venous flaps eventually survived. Histological examination revealed that postoperatively the blood flow in the skin of the pedicled arterialized venous flap became «re-reversed» again; there were no differences between mechanism of survival of venous flaps and other flaps. On the 7-14th day in the skin of all flaps were processes of neoangiogenesis and proliferation. Hence the best scenario for the clinical use of venous flaps unfolds when both revascularization and skin coverage are required.

  18. The possibility for use of venous flaps in plastic surgery

    SciTech Connect

    Baytinger, V. F. Kurochkina, O. S. Selianinov, K. V.; Baytinger, A. V.; Dzyuman, A. N.

    2015-11-17

    The use of venous flaps is controversial. The mechanism of perfusion of venous flaps is still not fully understood. The research was conducted on 56 white rats. In our experimental work we studied two different models of venous flaps: pedicled venous flap (PVF) and pedicled arterialized venous flap (PAVF). Our results showed that postoperative congestion was present in all flaps. However 66.7% of all pedicled venous flaps and 100% of all pedicled arterialized venous flaps eventually survived. Histological examination revealed that postoperatively the blood flow in the skin of the pedicled arterialized venous flap became «re-reversed» again; there were no differences between mechanism of survival of venous flaps and other flaps. On the 7-14th day in the skin of all flaps were processes of neoangiogenesis and proliferation. Hence the best scenario for the clinical use of venous flaps unfolds when both revascularization and skin coverage are required.

  19. HIP MUSCLE ACTIVATION AND KNEE FRONTAL PLANE MOTION DURING WEIGHT BEARING THERAPEUTIC EXERCISES

    PubMed Central

    Lubahn, Amanda J.; Tyson, Tiffany L.; Merkitch, Kenneth W.; Reutemann, Paul; Chestnut, John Mark

    2011-01-01

    Purpose/Background: Hip abduction strengthening exercises may be critical in the prevention and rehabilitation of both overuse and traumatic injuries where knee frontal plane alignment is considered to be important. The purpose of the current investigation was to examine the muscular activation of the gluteus maximus and gluteus medius during the double-leg squat (DLS), single-leg squat (SLS), or front step-up (FSU), and the same exercises when an added load was used to pull the knee medially. Methods: Eighteen healthy females (ages 18-26) performed six exercises: DLS, DLS with load, FSU, FSU with load, SLS, and SLS with load. Integrated and peak surface electromyography of gluteus maximus and gluteus medius of the dominant leg were recorded and normalized. Motion analysis was used to measure knee abduction angle during each exercise. Results: SLS had the highest integrated and peak activation for both muscles, regardless of load. Adding load, only increased DLS integrated gluteus maximus activation (p=0.019). Load did not increase integrated gluteus medius or peak gluteus maximus activation. Adding load decreased SLS peak gluteus medius activation (p=0.003). Adding load increased peak knee abduction angle during DLS (p=0.013), FSU (p=0.000), and SLS (p=0.011). Conclusions: Overall, the SLS was most effective exercise for activating the gluteus maximus and gluteus medius. Applied knee load does not appear to increase muscle activation during SLS and FSU. DLS with an applied load may be more beneficial in activating the gluteus maximus. Overall, the use of applied loads appears to promote poorer musculoskeletal alignment in terms of peak knee valgus angle. Level of Evidence: 3 PMID:21713231

  20. Outperforming hummingbirds' load-lifting capability with a lightweight hummingbird-like flapping-wing mechanism.

    PubMed

    Leys, Frederik; Reynaerts, Dominiek; Vandepitte, Dirk

    2016-01-01

    The stroke-cam flapping mechanism presented in this paper closely mimics the wing motion of a hovering Rufous hummingbird. It is the only lightweight hummingbird-sized flapping mechanism which generates a harmonic wing stroke with both a high flapping frequency and a large stroke amplitude. Experiments on a lightweight prototype of this stroke-cam mechanism on a 50 mm-long wing demonstrate that a harmonic stroke motion is generated with a peak-to-peak stroke amplitude of 175° at a flapping frequency of 40 Hz. It generated a mass lifting capability of 5.1 g, which is largely sufficient to lift the prototype's mass of 3.39 g and larger than the mass-lifting capability of a Rufous hummingbird. The motor mass of a hummingbird-like robot which drives the stroke-cam mechanism is considerably larger (about five times) than the muscle mass of a hummingbird with comparable load-lifting capability. This paper presents a flapping wing nano aerial vehicle which is designed to possess the same lift- and thrust-generating principles of the Rufous hummingbird. The application is indoor flight. We give an overview of the wing kinematics and some specifications which should be met to develop an artificial wing, and also describe the applications of these in the mechanism which has been developed in this work. PMID:27444790

  1. Formation and evolution of flapping and ballooning waves in magnetospheric plasma sheet

    NASA Astrophysics Data System (ADS)

    Ma, J. Z. G.; Hirose, A.

    2016-05-01

    By adopting Lembége & Pellat's 2D plasma-sheet model, we investigate the flankward flapping motion and Sunward ballooning propagation driven by an external source (e.g., magnetic reconnection) produced initially at the sheet center. Within the ideal MHD framework, we adopt the WKB approximation to obtain the Taylor-Goldstein equation of magnetic perturbations. Fourier spectral method and Runge-Kutta method are employed in numerical simulations, respectively, under the flapping and ballooning conditions. Studies expose that the magnetic shears in the sheet are responsible for the flapping waves, while the magnetic curvature and the plasma gradient are responsible for the ballooning waves. In addition, the flapping motion has three phases in its temporal development: fast damping phase, slow recovery phase, and quasi-stabilized phase; it is also characterized by two patterns in space: propagating wave pattern and standing wave pattern. Moreover, the ballooning modes are gradually damped toward the Earth, with a wavelength in a scale size of magnetic curvature or plasma inhomogeneity, only 1-7% of the flapping one; the envelops of the ballooning waves are similar to that of the observed bursty bulk flows moving toward the Earth.

  2. Outperforming hummingbirds' load-lifting capability with a lightweight hummingbird-like flapping-wing mechanism.

    PubMed

    Leys, Frederik; Reynaerts, Dominiek; Vandepitte, Dirk

    2016-08-15

    The stroke-cam flapping mechanism presented in this paper closely mimics the wing motion of a hovering Rufous hummingbird. It is the only lightweight hummingbird-sized flapping mechanism which generates a harmonic wing stroke with both a high flapping frequency and a large stroke amplitude. Experiments on a lightweight prototype of this stroke-cam mechanism on a 50 mm-long wing demonstrate that a harmonic stroke motion is generated with a peak-to-peak stroke amplitude of 175° at a flapping frequency of 40 Hz. It generated a mass lifting capability of 5.1 g, which is largely sufficient to lift the prototype's mass of 3.39 g and larger than the mass-lifting capability of a Rufous hummingbird. The motor mass of a hummingbird-like robot which drives the stroke-cam mechanism is considerably larger (about five times) than the muscle mass of a hummingbird with comparable load-lifting capability. This paper presents a flapping wing nano aerial vehicle which is designed to possess the same lift- and thrust-generating principles of the Rufous hummingbird. The application is indoor flight. We give an overview of the wing kinematics and some specifications which should be met to develop an artificial wing, and also describe the applications of these in the mechanism which has been developed in this work.

  3. Outperforming hummingbirds’ load-lifting capability with a lightweight hummingbird-like flapping-wing mechanism

    PubMed Central

    Reynaerts, Dominiek; Vandepitte, Dirk

    2016-01-01

    ABSTRACT The stroke-cam flapping mechanism presented in this paper closely mimics the wing motion of a hovering Rufous hummingbird. It is the only lightweight hummingbird-sized flapping mechanism which generates a harmonic wing stroke with both a high flapping frequency and a large stroke amplitude. Experiments on a lightweight prototype of this stroke-cam mechanism on a 50 mm-long wing demonstrate that a harmonic stroke motion is generated with a peak-to-peak stroke amplitude of 175° at a flapping frequency of 40 Hz. It generated a mass lifting capability of 5.1 g, which is largely sufficient to lift the prototype's mass of 3.39 g and larger than the mass-lifting capability of a Rufous hummingbird. The motor mass of a hummingbird-like robot which drives the stroke-cam mechanism is considerably larger (about five times) than the muscle mass of a hummingbird with comparable load-lifting capability. This paper presents a flapping wing nano aerial vehicle which is designed to possess the same lift- and thrust-generating principles of the Rufous hummingbird. The application is indoor flight. We give an overview of the wing kinematics and some specifications which should be met to develop an artificial wing, and also describe the applications of these in the mechanism which has been developed in this work. PMID:27444790

  4. Flow visualization and wall shear stress of a flapping model hummingbird wing

    NASA Astrophysics Data System (ADS)

    Swanton, Erik W. M.; Vanier, Blake A.; Mohseni, Kamran

    2010-09-01

    The unsteady low Reynolds number aerodynamics of flapping flight was investigated experimentally through flow visualization by suspended particle imagery and wall shear stress measurement from micro-array hot-film anemometry. In conjunction, a mechanism was developed to create a flapping motion with three degrees of freedom and adjustable flapping frequency. The flapping kinematics and wing shape were selected for dynamic similarity to a hummingbird during hovering flight. Flow visualization was used to validate the anemometry observations of leading edge vortex (LEV) characteristics and to investigate the necessity of spanwise flow in LEV stability. The shear sensors determined LEV characteristics throughout the translation section of the stroke period for various wing speeds. It was observed that a minimum frequency between 2 and 3.5 Hz is required for the formation and stabilization of a LEV. The vortex strength peaked around 30% of the flapping cycle (corresponding to just past the translation midpoint), which agrees with results from previous studies conducted by others. The shear sensors also indicated a mild growth in LEV size during translation sections of the wing’s motion. This growth magnitude was nearly constant through a range of operating frequencies.

  5. Dopamine Activation Preserves Visual Motion Perception Despite Noise Interference of Human V5/MT

    PubMed Central

    Yousif, Nada; Fu, Richard Z.; Abou-El-Ela Bourquin, Bilal; Bhrugubanda, Vamsee; Schultz, Simon R.

    2016-01-01

    When processing sensory signals, the brain must account for noise, both noise in the stimulus and that arising from within its own neuronal circuitry. Dopamine receptor activation is known to enhance both visual cortical signal-to-noise-ratio (SNR) and visual perceptual performance; however, it is unknown whether these two dopamine-mediated phenomena are linked. To assess this, we used single-pulse transcranial magnetic stimulation (TMS) applied to visual cortical area V5/MT to reduce the SNR focally and thus disrupt visual motion discrimination performance to visual targets located in the same retinotopic space. The hypothesis that dopamine receptor activation enhances perceptual performance by improving cortical SNR predicts that dopamine activation should antagonize TMS disruption of visual perception. We assessed this hypothesis via a double-blinded, placebo-controlled study with the dopamine receptor agonists cabergoline (a D2 agonist) and pergolide (a D1/D2 agonist) administered in separate sessions (separated by 2 weeks) in 12 healthy volunteers in a William's balance-order design. TMS degraded visual motion perception when the evoked phosphene and the visual stimulus overlapped in time and space in the placebo and cabergoline conditions, but not in the pergolide condition. This suggests that dopamine D1 or combined D1 and D2 receptor activation enhances cortical SNR to boost perceptual performance. That local visual cortical excitability was unchanged across drug conditions suggests the involvement of long-range intracortical interactions in this D1 effect. Because increased internal noise (and thus lower SNR) can impair visual perceptual learning, improving visual cortical SNR via D1/D2 agonist therapy may be useful in boosting rehabilitation programs involving visual perceptual training. SIGNIFICANCE STATEMENT In this study, we address the issue of whether dopamine activation improves visual perception despite increasing sensory noise in the visual cortex

  6. Driving technology for improving motion quality of active-matrix organic light-emitting diode display

    NASA Astrophysics Data System (ADS)

    Kim, Jongbin; Kim, Minkoo; Kim, Jong-Man; Kim, Seung-Ryeol; Lee, Seung-Woo

    2014-09-01

    This paper reports transient response characteristics of active-matrix organic light emitting diode (AMOLED) displays for mobile applications. This work reports that the rising responses look like saw-tooth waveform and are not always faster than those of liquid crystal displays. Thus, a driving technology is proposed to improve the rising transient responses of AMOLED based on the overdrive (OD) technology. We modified the OD technology by combining it with a dithering method because the conventional OD method cannot successfully enhance all the rising responses. Our method can improve all the transitions of AMOLED without modifying the conventional gamma architecture of drivers. A new artifact is found when OD is applied to certain transitions. We propose an optimum OD selection method to mitigate the artifact. The implementation results show the proposed technology can successfully improve motion quality of scrolling texts as well as moving pictures in AMOLED displays.

  7. Aftershock activity of the 2015 Gorkha, Nepal, earthquake determined using the Kathmandu strong motion seismographic array

    NASA Astrophysics Data System (ADS)

    Ichiyanagi, Masayoshi; Takai, Nobuo; Shigefuji, Michiko; Bijukchhen, Subeg; Sasatani, Tsutomu; Rajaure, Sudhir; Dhital, Megh Raj; Takahashi, Hiroaki

    2016-02-01

    The characteristics of aftershock activity of the 2015 Gorkha, Nepal, earthquake (Mw 7.8) were evaluated. The mainshock and aftershocks were recorded continuously by the international Kathmandu strong motion seismographic array operated by Hokkaido University and Tribhuvan University. Full waveform data without saturation for all events enabled us to clarify aftershock locations and decay characteristics. The aftershock distribution was determined using the estimated local velocity structure. The hypocenter distribution in the Kathmandu metropolitan region was well determined and indicated earthquakes located shallower than 12 km depth, suggesting that aftershocks occurred at depths shallower than the Himalayan main thrust fault. Although numerical investigation suggested less resolution for the depth component, the regional aftershock epicentral distribution of the entire focal region clearly indicated earthquakes concentrated in the eastern margin of the major slip region of the mainshock. The calculated modified Omori law's p value of 1.35 suggests rapid aftershock decay and a possible high temperature structure in the aftershock region.

  8. Recommended survey designs for occupancy modelling using motion-activated cameras: insights from empirical wildlife data

    PubMed Central

    Lewis, Jesse S.; Gerber, Brian D.

    2014-01-01

    Motion-activated cameras are a versatile tool that wildlife biologists can use for sampling wild animal populations to estimate species occurrence. Occupancy modelling provides a flexible framework for the analysis of these data; explicitly recognizing that given a species occupies an area the probability of detecting it is often less than one. Despite the number of studies using camera data in an occupancy framework, there is only limited guidance from the scientific literature about survey design trade-offs when using motion-activated cameras. A fuller understanding of these trade-offs will allow researchers to maximise available resources and determine whether the objectives of a monitoring program or research study are achievable. We use an empirical dataset collected from 40 cameras deployed across 160 km2 of the Western Slope of Colorado, USA to explore how survey effort (number of cameras deployed and the length of sampling period) affects the accuracy and precision (i.e., error) of the occupancy estimate for ten mammal and three virtual species. We do this using a simulation approach where species occupancy and detection parameters were informed by empirical data from motion-activated cameras. A total of 54 survey designs were considered by varying combinations of sites (10–120 cameras) and occasions (20–120 survey days). Our findings demonstrate that increasing total sampling effort generally decreases error associated with the occupancy estimate, but changing the number of sites or sampling duration can have very different results, depending on whether a species is spatially common or rare (occupancy = ψ) and easy or hard to detect when available (detection probability = p). For rare species with a low probability of detection (i.e., raccoon and spotted skunk) the required survey effort includes maximizing the number of sites and the number of survey days, often to a level that may be logistically unrealistic for many studies. For common species with

  9. A Circular Motion Activity with Hot Wheels® Rev-Ups

    NASA Astrophysics Data System (ADS)

    Wagner, Glenn

    2009-02-01

    Hot Wheels® Rev-Ups provide a pedagogically engaging and inexpensive culminating activity for the application of circular motion with constant speed in introductory mechanics. The introductory Rev-Up, shown in Fig. 1, consists of a very durable car with two strong magnets built into the front and back of the car. The track is a piece of flexible plastic with a built-in metallic strip through its center that can then be formed into a circle. Pushing the car forward several times on a flat surface allows the car to move in a vertical circle when placed inside the track. What makes this toy attractive is that the gearing system allows the car to move at a relatively constant speed for about three to five seconds before slowing down appreciably.

  10. Recommended survey designs for occupancy modelling using motion-activated cameras: insights from empirical wildlife data.

    PubMed

    Shannon, Graeme; Lewis, Jesse S; Gerber, Brian D

    2014-01-01

    Motion-activated cameras are a versatile tool that wildlife biologists can use for sampling wild animal populations to estimate species occurrence. Occupancy modelling provides a flexible framework for the analysis of these data; explicitly recognizing that given a species occupies an area the probability of detecting it is often less than one. Despite the number of studies using camera data in an occupancy framework, there is only limited guidance from the scientific literature about survey design trade-offs when using motion-activated cameras. A fuller understanding of these trade-offs will allow researchers to maximise available resources and determine whether the objectives of a monitoring program or research study are achievable. We use an empirical dataset collected from 40 cameras deployed across 160 km(2) of the Western Slope of Colorado, USA to explore how survey effort (number of cameras deployed and the length of sampling period) affects the accuracy and precision (i.e., error) of the occupancy estimate for ten mammal and three virtual species. We do this using a simulation approach where species occupancy and detection parameters were informed by empirical data from motion-activated cameras. A total of 54 survey designs were considered by varying combinations of sites (10-120 cameras) and occasions (20-120 survey days). Our findings demonstrate that increasing total sampling effort generally decreases error associated with the occupancy estimate, but changing the number of sites or sampling duration can have very different results, depending on whether a species is spatially common or rare (occupancy = ψ) and easy or hard to detect when available (detection probability = p). For rare species with a low probability of detection (i.e., raccoon and spotted skunk) the required survey effort includes maximizing the number of sites and the number of survey days, often to a level that may be logistically unrealistic for many studies. For common species with

  11. Synergic co-activation of muscles in elbow flexion via fractional Brownian motion.

    PubMed

    Chang, Shyang; Hsyu, Ming-Chun; Cheng, Hsiu-Yao; Hsieh, Sheng-Hwu

    2008-12-31

    In reflex and volitional actions, co-activations of agonist and antagonist muscles are believed to be present. Recent studies indicate that such co-activations can be either synergic or dyssynergic. The aim of this paper is to investigate if the co-activations of biceps brachii, brachialis, and triceps brachii during volitional elbow flexion are in the synergic or dyssynergic state. In this study, two groups with each containing six healthy male volunteers participated. Each person of the first group performed 30 trials of volitional elbow flexion while each of the second group performed 30 trials of passive elbow flexion as control experiments. Based on the model of fractional Brownian motion, the intensity and frequency information of the surface electromyograms (EMGs) could be extracted simultaneously. No statistically significant changes were found in the control group. As to the other group, results indicated that the surface EMGs of all five muscle groups were temporally synchronized in frequencies with persistent intensities during each elbow flexion. In addition, the mean values of fractal dimensions for rest and volitional flexion states revealed significant differences with P < 0.01. The obtained positive results suggest that these muscle groups work together synergically to facilitate elbow flexion during the co-activations.

  12. Spinal Motion and Muscle Activity during Active Trunk Movements - Comparing Sheep and Humans Adopting Upright and Quadrupedal Postures.

    PubMed

    Valentin, Stephanie; Licka, Theresia F

    2016-01-01

    Sheep are used as models for the human spine, yet comparative in vivo data necessary for validation is limited. The purpose of this study was therefore to compare spinal motion and trunk muscle activity during active trunk movements in sheep and humans. Three-dimensional kinematic data as well as surface electromyography (sEMG) of spinal flexion and extension was compared in twenty-four humans in upright (UR) and 4-point kneeling (KN) postures and in 17 Austrian mountain sheep. Kinematic markers were attached over the sacrum, posterior iliac spines, and spinous and transverse processes of T5, T8, T11, L2 and L5 in humans and over the sacrum, tuber sacrale, T5, T8, T12, L3 and L7 in sheep. The activity of erector spinae (ES), rectus abdominis (RA), obliquus externus (OE), and obliquus internus (OI) were collected. Maximum sEMG (MOE) was identified for each muscle and trial, and reported as a percentage (MOE%) of the overall maximally observed sEMG from all trials. Spinal range of motion was significantly smaller in sheep compared to humans (UR / KN) during flexion (sheep: 6-11°; humans 12-34°) and extension (sheep: 4°; humans: 11-17°). During extension, MOE% of ES was greater in sheep (median: 77.37%) than UR humans (24.89%), and MOE% of OE and OI was greater in sheep (OE 76.20%; OI 67.31%) than KN humans (OE 21.45%; OI 19.34%), while MOE% of RA was lower in sheep (21.71%) than UR humans (82.69%). During flexion, MOE% of RA was greater in sheep (83.09%) than humans (KN 47.42%; UR 41.38%), and MOE% of ES in sheep (45.73%) was greater than KN humans (14.45%), but smaller than UR humans (72.36%). The differences in human and sheep spinal motion and muscle activity suggest that caution is warranted when ovine data are used to infer human spine biomechanics.

  13. Spinal Motion and Muscle Activity during Active Trunk Movements – Comparing Sheep and Humans Adopting Upright and Quadrupedal Postures

    PubMed Central

    Valentin, Stephanie; Licka, Theresia F.

    2016-01-01

    Sheep are used as models for the human spine, yet comparative in vivo data necessary for validation is limited. The purpose of this study was therefore to compare spinal motion and trunk muscle activity during active trunk movements in sheep and humans. Three-dimensional kinematic data as well as surface electromyography (sEMG) of spinal flexion and extension was compared in twenty-four humans in upright (UR) and 4-point kneeling (KN) postures and in 17 Austrian mountain sheep. Kinematic markers were attached over the sacrum, posterior iliac spines, and spinous and transverse processes of T5, T8, T11, L2 and L5 in humans and over the sacrum, tuber sacrale, T5, T8, T12, L3 and L7 in sheep. The activity of erector spinae (ES), rectus abdominis (RA), obliquus externus (OE), and obliquus internus (OI) were collected. Maximum sEMG (MOE) was identified for each muscle and trial, and reported as a percentage (MOE%) of the overall maximally observed sEMG from all trials. Spinal range of motion was significantly smaller in sheep compared to humans (UR / KN) during flexion (sheep: 6–11°; humans 12–34°) and extension (sheep: 4°; humans: 11–17°). During extension, MOE% of ES was greater in sheep (median: 77.37%) than UR humans (24.89%), and MOE% of OE and OI was greater in sheep (OE 76.20%; OI 67.31%) than KN humans (OE 21.45%; OI 19.34%), while MOE% of RA was lower in sheep (21.71%) than UR humans (82.69%). During flexion, MOE% of RA was greater in sheep (83.09%) than humans (KN 47.42%; UR 41.38%), and MOE% of ES in sheep (45.73%) was greater than KN humans (14.45%), but smaller than UR humans (72.36%). The differences in human and sheep spinal motion and muscle activity suggest that caution is warranted when ovine data are used to infer human spine biomechanics. PMID:26741136

  14. Comprehensive Evaluation of Risk Factors and Management of Impending Flap Loss in 2138 Breast Free Flaps.

    PubMed

    Chang, Edward I; Chang, Eric I; Soto-Miranda, Miguel A; Zhang, Hong; Nosrati, Naveed; Crosby, Melissa A; Reece, Gregory P; Robb, Geoffrey L; Chang, David W

    2016-01-01

    Loss of a breast free flap is a relatively rare but catastrophic occurrence. Our study aims to identify risk factors for flap loss and to assess whether different salvage techniques affect flap salvage. We performed a retrospective review of all breast free flaps performed at a single institution from 2000 to 2010. Overall, 2138 flaps were performed in 1608 patients (unilateral, 1120 and bilateral, 488) with 44 flap losses (2.1%). Age, body mass index, smoking, radiation, chemotherapy, and surgeon experience did not affect flap loss. Abdominal flaps based on a single perforator were at significantly higher risk for flap loss compared with flaps based on multiple perforators (P = 0.0007). Subgroup analysis of the subset of 166 compromised free flaps (flaps requiring a return to the operating room, an intraoperative anastomotic revision, or loss/partial loss of a free flap) demonstrated deep inferior epigastric perforator, and other flaps (superficial inferior epigastric artery and superior gluteal artery perforator) were significantly associated with flap loss [odds ratio (OR) 5.20; P = 0.03 and OR 6.91; P = 0.0004, respectively] compared with transverse rectus abdominis myocutaneous and muscle-sparing transverse rectus abdominis myocutaneous flaps. Although an intraoperative complication was not associated with a flap loss, the need for a reoperation was strongly predictive (P < 0.0001). Flap salvage was the highest within the first 24 hours (83.7%) and significantly less between days 1 and 3 (38.6%; P < 0.0001) and beyond 4 days (29.4%; P < 0.0001). Longer ischemia time was significantly associated with flap loss (P = 0.04). Salvage techniques (aspirin, heparinzation, thrombectomy, and thrombolytic) had no impact on flap salvage rates. Heparinization and thrombolytics were associated with higher loss rates (OR 3.40; P = 0.003 and OR 10.36; P < 0.0001, respectively). Free flap loss following breast reconstruction is multifactorial with higher losses in superficial

  15. Composite tissue flap at perforating branches of saphenous artery: a new design for repairing composite tissue defects in anterior knee

    PubMed Central

    Sun, Guangfeng; Nie, Kaiyu; Jin, Wenhu; Wei, Zairong; Qi, Jianping; Wang, Dali

    2015-01-01

    So far it has been difficult to repair and reconstruct the composite tissue defects in knee. Saphenous artery flap has been widely used to repair complex wounds, but the design and clinical application of composite tissue flap at perforating branches of saphenous artery were not reported. In this research, we design a new composite tissue flap by carrying fascial flap in the medial gastrocnemius muscle with perforators flap in saphenous artery to repair and reconstruct the composite tissue defects in knee. By anatomic observation and analysis, we find that there exists blood-supply in netty form among saphenous arteries, medial artery below the knee, intermuscular branch in high-order position of posterior tibial artery and perforating branch in medial artery of calf. We chose saphenous artery as blood-supplying artery; utilized the netty blood-supplying mode in middle-up and medial part of shank; cut the composite tissue flap at perforating branches of saphenous artery with fascial flap carried in the medial gastrocnemius muscle; reconstructed the ligamentum patellae using medial head of gastrocnemius muscle and Achilles’s tendon; and covered the wounds at front side of knee with flap. Composite tissues were survived completely, free from infection at wounds and exosmosis of joint fluid. Motion function of knee-joint proved satisfactory, and ambulatory function was recovered. There was no complication in donor site. Composite tissue flap at perforating branches of saphenous artery with fascial flap carried in the medial gastrocnemius muscle is one of the most ideal solutions for repairing the composite tissue defects at front side of knee joint. PMID:26885090

  16. Dynamic analysis of astronaut motions in microgravity: Applications for Extravehicular Activity (EVA)

    NASA Technical Reports Server (NTRS)

    Newman, Dava J.

    1995-01-01

    Simulations of astronaut motions during extravehicular activity (EVA) tasks were performed using computational multibody dynamics methods. The application of computational dynamic simulation to EVA was prompted by the realization that physical microgravity simulators have inherent limitations: viscosity in neutral buoyancy tanks; friction in air bearing floors; short duration for parabolic aircraft; and inertia and friction in suspension mechanisms. These limitations can mask critical dynamic effects that later cause problems during actual EVA's performed in space. Methods of formulating dynamic equations of motion for multibody systems are discussed with emphasis on Kane's method, which forms the basis of the simulations presented herein. Formulation of the equations of motion for a two degree of freedom arm is presented as an explicit example. The four basic steps in creating the computational simulations were: system description, in which the geometry, mass properties, and interconnection of system bodies are input to the computer; equation formulation based on the system description; inverse kinematics, in which the angles, velocities, and accelerations of joints are calculated for prescribed motion of the endpoint (hand) of the arm; and inverse dynamics, in which joint torques are calculated for a prescribed motion. A graphical animation and data plotting program, EVADS (EVA Dynamics Simulation), was developed and used to analyze the results of the simulations that were performed on a Silicon Graphics Indigo2 computer. EVA tasks involving manipulation of the Spartan 204 free flying astronomy payload, as performed during Space Shuttle mission STS-63 (February 1995), served as the subject for two dynamic simulations. An EVA crewmember was modeled as a seven segment system with an eighth segment representing the massive payload attached to the hand. For both simulations, the initial configuration of the lower body (trunk, upper leg, and lower leg) was a neutral

  17. Comparison of electromyographic activity and range of neck motion in violin students with and without neck pain during playing.

    PubMed

    Park, Kyue-nam; Kwon, Oh-yun; Ha, Sung-min; Kim, Su-jung; Choi, Hyun-jung; Weon, Jong-hyuck

    2012-12-01

    Neck pain is common in violin students during a musical performance. The purpose of this study was to compare electromyographic (EMG) activity in superficial neck muscles with neck motion when playing the violin as well as neck range of motion (ROM) at rest, between violin students with and without neck pain. Nine violin students with neck pain and nine age- and gender-matched subjects without neck pain were recruited. Muscle activity of the bilateral upper trapezius, sternocleidomastoid, and superficial cervical extensor muscles was measured using surface EMG. Kinematic data on neck motion while playing and active neck ROM were also measured using a three-dimensional motion analysis system. Independent t-tests were used to compare EMG activity with kinematic data between groups. These analyses revealed that while playing, both the angle of left lateral bending and leftward rotation of the cervical spine were significantly greater in the neck pain group than among those without neck pain. Similarly, EMG activity of the left upper trapezius, both cervical extensors, and both sternocleidomastoid muscles were significantly greater in the neck pain group. The active ROM of left axial rotation was significantly lower in the neck pain group. These results suggest that an asymmetric playing posture and the associated increased muscle activity as well as decreased neck axial rotation may contribute to neck pain in violin students. PMID:23247874

  18. Comparison of electromyographic activity and range of neck motion in violin students with and without neck pain during playing.

    PubMed

    Park, Kyue-nam; Kwon, Oh-yun; Ha, Sung-min; Kim, Su-jung; Choi, Hyun-jung; Weon, Jong-hyuck

    2012-12-01

    Neck pain is common in violin students during a musical performance. The purpose of this study was to compare electromyographic (EMG) activity in superficial neck muscles with neck motion when playing the violin as well as neck range of motion (ROM) at rest, between violin students with and without neck pain. Nine violin students with neck pain and nine age- and gender-matched subjects without neck pain were recruited. Muscle activity of the bilateral upper trapezius, sternocleidomastoid, and superficial cervical extensor muscles was measured using surface EMG. Kinematic data on neck motion while playing and active neck ROM were also measured using a three-dimensional motion analysis system. Independent t-tests were used to compare EMG activity with kinematic data between groups. These analyses revealed that while playing, both the angle of left lateral bending and leftward rotation of the cervical spine were significantly greater in the neck pain group than among those without neck pain. Similarly, EMG activity of the left upper trapezius, both cervical extensors, and both sternocleidomastoid muscles were significantly greater in the neck pain group. The active ROM of left axial rotation was significantly lower in the neck pain group. These results suggest that an asymmetric playing posture and the associated increased muscle activity as well as decreased neck axial rotation may contribute to neck pain in violin students.

  19. Wearable motion sensors to continuously measure real-world physical activities

    PubMed Central

    Dobkin, Bruce H.

    2014-01-01

    Purpose of review Rehabilitation for sensorimotor impairments aims to improve daily activities, walking, exercise, and motor skills. Monitoring of practice and measuring outcomes, however, is usually restricted to laboratory-based procedures and self-reports. Mobile health devices may reverse these confounders of daily care and research trials. Recent findings Wearable, wireless motion sensor data, analyzed by activity pattern-recognition algorithms, can describe the type, quantity, and quality of mobility-related activities in the community. Data transmission from sensors to the cell phone and Internet enable continuous monitoring. Remote access to laboratory-quality data about walking speed, duration and distance, gait asymmetry and smoothness of movements, as well as cycling, exercise, and skills practice, opens new opportunities to engage patients in progressive, personalized therapies with feedback about performance. Clinical trial designs will be able to include remote verification of the integrity of complex physical interventions and compliance with practice, as well as capture repeated, ecologically sound, ratio-scale outcome measures. Summary Given the progressively falling cost of miniaturized wearable gyroscopes, accelerometers, and other physiologic sensors, as well as inexpensive data transmission, sensing systems may become as ubiquitous as cell phones for health care. Neurorehabilitation can develop these mobile health platforms for daily care and clinical trials to improve exercise and fitness, skills learning, and physical functioning. PMID:24136126

  20. A pigeon-inspired design for a biomimetic flapping wing

    NASA Astrophysics Data System (ADS)

    Mahardika, Nanang; Nguyen, Quoc Viet; Park, Hoon Cheol

    2010-04-01

    As an effort to explore the potential implementation of wing feather separation and lead-lagging motion to a flapping wing, a biomimetic flapper with separable outer wings has been designed and demonstrated. The artificial wing feather separation is implemented to the biomimetic wing by dividing the wing into inner and outer wings. The features of flapping, lead-lagging and feather separation of the flapper are captured by a high-speed camera for evaluation. The performance of the biomimetic flapper with separable outer wings is compared with that of a flapper with inseparable outer wings in terms of lift and thrust production. For low flapping frequency ranging from 2.47 Hz to 3.90 Hz, the biomimetic flapper shows higher thrust and lift generation capability, which is demonstrated from a series of experiments. The experiments show that the outer parts of the separable wing are able to deform largely resulting smaller amount of drag production during upstroke, while still producing relatively larger lift and thrust during downstroke.

  1. The Wing Apparatus and Flapping Behavior of Hymenoptera

    NASA Astrophysics Data System (ADS)

    Sudo, Seiichi; Tsuyuki, Koji; Ito, Yoshiyasu; Tani, Junji

    The wing apparatus of Hymenoptera was observed with a scanning electron microscope, and the structure and function of insect wings were studied. The measurements of displacement of extrinsic skeleton vibration produced by wing flapping of a wasp were made by an optical displacement detector system. The free flight of the wasp was analyzed by a three dimensional motion analysis system. The results of a series of measurements revealed the flight characteristics of Hymenoptera, such as the wing tip velocity, wing path, wave form of extrinsic skeleton vibration, and so forth.

  2. Bifurcation theory applied to aircraft motions

    NASA Technical Reports Server (NTRS)

    Hui, W. H.; Tobak, M.

    1985-01-01

    Bifurcation theory is used to analyze the nonlinear dynamic stability characteristics of single-degree-of-freedom motions of an aircraft or a flap about a trim position. The bifurcation theory analysis reveals that when the bifurcation parameter, e.g., the angle of attack, is increased beyond a critical value at which the aerodynamic damping vanishes, a new solution representing finite-amplitude periodic motion bifurcates from the previously stable steady motion. The sign of a simple criterion, cast in terms of aerodynamic properties, determines whether the bifurcating solution is stable (supercritical) or unstable (subcritical). For the pitching motion of a flap-plate airfoil flying at supersonic/hypersonic speed, and for oscillation of a flap at transonic speed, the bifurcation is subcritical, implying either that exchanges of stability between steady and periodic motion are accompanied by hysteresis phenomena, or that potentially large aperiodic departures from steady motion may develop. On the other hand, for the rolling oscillation of a slender delta wing in subsonic flight (wing rock), the bifurcation is found to be supercritical. This and the predicted amplitude of the bifurcation periodic motion are in good agreement with experiments.

  3. A parallelogram-based compliant remote-center-of-motion stage for active parallel alignment.

    PubMed

    Qu, Jianliang; Chen, Weihai; Zhang, Jianbin

    2014-09-01

    Parallel alignment stage with remote-center-of-motion (RCM) is of key importance in precision out-of-plane aligning since it can eliminate the harmful lateral displacement generated at the output platform. This paper presents the development of a parallelogram-based compliant RCM stage for active parallel alignment. Different from conventional parallelogram-based RCM mechanism, the proposed stage is designed with compliant mechanisms, which endows the stage with many attractive merits when used in precision micro-/nanomanipulations. A symmetric double-parallelogram mechanism (SDPM) based on flexure hinges is developed as the rotary guiding component to realize desired RCM function. Due to the geometrical constraint of the SDPM, the operating space of the stage can be easily adjusted by bending the input links without loss of rotational precision. The stage is driven by a piezoelectric actuator and its output motion is measured by non-contact displacement sensors. Based on pseudo-rigid-body simplification method, the analytical models predicting kinematics, statics, and dynamics of the RCM stage have been established. Besides, the dimensional optimization is conducted in order to maximize the first resonance frequency of the stage. After that, finite element analysis is conducted to validate the established models and the prototype of the stage is fabricated for performance tests. The experimental results show that the developed RCM stage has a rotational range of 1.45 mrad while the maximum center shift of the RCM point is as low as 1 μm, which validate the effectiveness of the proposed scheme.

  4. A parallelogram-based compliant remote-center-of-motion stage for active parallel alignment

    NASA Astrophysics Data System (ADS)

    Qu, Jianliang; Chen, Weihai; Zhang, Jianbin

    2014-09-01

    Parallel alignment stage with remote-center-of-motion (RCM) is of key importance in precision out-of-plane aligning since it can eliminate the harmful lateral displacement generated at the output platform. This paper presents the development of a parallelogram-based compliant RCM stage for active parallel alignment. Different from conventional parallelogram-based RCM mechanism, the proposed stage is designed with compliant mechanisms, which endows the stage with many attractive merits when used in precision micro-/nanomanipulations. A symmetric double-parallelogram mechanism (SDPM) based on flexure hinges is developed as the rotary guiding component to realize desired RCM function. Due to the geometrical constraint of the SDPM, the operating space of the stage can be easily adjusted by bending the input links without loss of rotational precision. The stage is driven by a piezoelectric actuator and its output motion is measured by non-contact displacement sensors. Based on pseudo-rigid-body simplification method, the analytical models predicting kinematics, statics, and dynamics of the RCM stage have been established. Besides, the dimensional optimization is conducted in order to maximize the first resonance frequency of the stage. After that, finite element analysis is conducted to validate the established models and the prototype of the stage is fabricated for performance tests. The experimental results show that the developed RCM stage has a rotational range of 1.45 mrad while the maximum center shift of the RCM point is as low as 1 μm, which validate the effectiveness of the proposed scheme.

  5. Benefits of using omental pedicle flap over muscle flap for closure of open window thoracotomy

    PubMed Central

    Chikaishi, Yasuhiro; Kuwata, Taiji; Takenaka, Masaru; Oka, Soichi; Hirai, Ayako; Imanishi, Naoko; Kuroda, Koji; Tanaka, Fumihiro

    2016-01-01

    Background Open window thoracotomy (OWT) as well as its closure are challenging. Transposition of omental pedicle and muscle flaps is often performed for OWT closure; however, the better technique among the two is unknown. The purpose of this series was to evaluate the outcomes of using both omental pedicle and muscle flaps for the aforementioned closure. Methods This was an observational retrospective cohort study on 27 consecutive patients who underwent OWT closure at a single institution between January 2005 and December 2014. The operation was performed using either omental pedicle or muscle flap with thoracoplasty. We compared both techniques in terms of the patient background [sex, age, body mass index (BMI) and C-reactive protein (CRP) before OWT and serum albumin levels before OWT closure], presence of methicillin-resistant Staphylococcus aureus (MRSA) infection, rate of bronchopleural fistula (BPF), duration of OWT, recurrence of local infection, morbidity, duration of indwelling drainage after operation, success, mortality and postoperative hospital stay. Results There were 9 (33.3%) omental pedicle flap procedures and 18 (66.7%) muscle flap procedures. The rate of local recurrence after closure of OWT was significantly higher with muscle flap than with omental pedicle flap (0% vs. 50.0%, P=0.012). The median duration of postoperative hospital stay was significantly shorter with omental pedicle flap than that with muscle flap (16.0 vs. 41.5 days, P=0.037). Mortality was observed in 2 patients (11.2%) in the muscle flap group and no patient in the omental pedicle flap group. Success rate was similar between the two groups (100% for omental pedicle flap vs. 83.3% for muscle flap). Conclusions Omental pedicle flap was superior to muscle flap in terms of reducing local recurrence and shortening postoperative hospital stay. However, mortality, morbidity and success rates were not affected by the choice of flap. PMID:27499959

  6. Motion compensation for brain PET imaging using wireless MR active markers in simultaneous PET-MR: phantom and non-human primate studies

    PubMed Central

    Huang, Chuan; Ackerman, Jerome L.; Petibon, Yoann; Normandin, Marc D.; Brady, Thomas J.; El Fakhri, Georges; Ouyang, Jinsong

    2014-01-01

    Brain PET scanning plays an important role in the diagnosis, prognostication and monitoring of many brain diseases. Motion artifacts from head motion are one of the major hurdles in brain PET. In this work, we propose to use wireless MR active markers to track head motion in real time during a simultaneous PET-MR brain scan and incorporate the motion measured by the markers in the listmode PET reconstruction. Several wireless MR active markers and a dedicated fast MR tracking pulse sequence module were built. Data were acquired on an ACR Flangeless PET phantom with multiple spheres and a non-human primate with and without motion. Motions of the phantom and monkey’s head were measured with the wireless markers using a dedicated MR tracking sequence module. The motion PET data were reconstructed using list-mode reconstruction with and without motion correction. Static reference was used as gold standard for quantitative analysis. The motion artifacts, which were prominent on the images without motion correction, were eliminated by the wireless marker based motion correction in both the phantom and monkey experiments. Quantitative analysis was performed on the phantom motion data from 24 independent noise realizations. The reduction of bias of sphere-to-background PET contrast by active marker based motion correction ranges from 26% to 64% and 17% to 25% for hot (i.e., radioactive) and cold (i.e., non-radioactive) spheres, respectively. The motion correction improved the channelized Hotelling observer signal-to-noise ratio of the spheres by 1.2 to 6.9 depending on their locations and sizes. The proposed wireless MR active marker based motion correction technique removes the motion artifacts in the reconstructed PET images and yields accurate quantitative values. PMID:24418501

  7. Motion compensation for brain PET imaging using wireless MR active markers in simultaneous PET-MR: phantom and non-human primate studies.

    PubMed

    Huang, Chuan; Ackerman, Jerome L; Petibon, Yoann; Normandin, Marc D; Brady, Thomas J; El Fakhri, Georges; Ouyang, Jinsong

    2014-05-01

    Brain PET scanning plays an important role in the diagnosis, prognostication and monitoring of many brain diseases. Motion artifacts from head motion are one of the major hurdles in brain PET. In this work, we propose to use wireless MR active markers to track head motion in real time during a simultaneous PET-MR brain scan and incorporate the motion measured by the markers in the listmode PET reconstruction. Several wireless MR active markers and a dedicated fast MR tracking pulse sequence module were built. Data were acquired on an ACR Flangeless PET phantom with multiple spheres and a non-human primate with and without motion. Motions of the phantom and monkey's head were measured with the wireless markers using a dedicated MR tracking sequence module. The motion PET data were reconstructed using list-mode reconstruction with and without motion correction. Static reference was used as gold standard for quantitative analysis. The motion artifacts, which were prominent on the images without motion correction, were eliminated by the wireless marker based motion correction in both the phantom and monkey experiments. Quantitative analysis was performed on the phantom motion data from 24 independent noise realizations. The reduction of bias of sphere-to-background PET contrast by active marker based motion correction ranges from 26% to 64% and 17% to 25% for hot (i.e., radioactive) and cold (i.e., non-radioactive) spheres, respectively. The motion correction improved the channelized Hotelling observer signal-to-noise ratio of the spheres by 1.2 to 6.9 depending on their locations and sizes. The proposed wireless MR active marker based motion correction technique removes the motion artifacts in the reconstructed PET images and yields accurate quantitative values.

  8. Freestyle Local Perforator Flaps for Facial Reconstruction.

    PubMed

    Lee, Jun Yong; Kim, Ji Min; Kwon, Ho; Jung, Sung-No; Shim, Hyung Sup; Kim, Sang Wha

    2015-01-01

    For the successful reconstruction of facial defects, various perforator flaps have been used in single-stage surgery, where tissues are moved to adjacent defect sites. Our group successfully performed perforator flap surgery on 17 patients with small to moderate facial defects that affected the functional and aesthetic features of their faces. Of four complicated cases, three developed venous congestion, which resolved in the subacute postoperative period, and one patient with partial necrosis underwent minor revision. We reviewed the literature on freestyle perforator flaps for facial defect reconstruction and focused on English articles published in the last five years. With the advance of knowledge regarding the vascular anatomy of pedicled perforator flaps in the face, we found that some perforator flaps can improve functional and aesthetic reconstruction for the facial defects. We suggest that freestyle facial perforator flaps can serve as alternative, safe, and versatile treatment modalities for covering small to moderate facial defects. PMID:26236734

  9. Davis flap: the glory still present

    PubMed Central

    El-Sabbagh, Ahmed Hassan

    2016-01-01

    Background: Upper third defects of the ear are too large to be closed primarily without distorting the auricle. Full thickness defects can be reconstructed with local flaps. In this article, Davis flap was used to fill the upper third defects of the ear with some modifications. Patients and methods: Eight patients underwent reconstruction of full thickness auricular defects with Davis flaps from July 2012 to December 2014. The posterior surface of the flap and the raw area of conchal area were covered by full thickness graft taken from posterior surface of ear. Results: All flaps survived. No congestion was noted. The donor sites and skin grafts healed uneventfully. Conclusion: Davis flap is a simple and reproducible tool for reconstruction of upper third of ear. PMID:27274439

  10. Ground Motion Simulation for a Large Active Fault System using Empirical Green's Function Method and the Strong Motion Prediction Recipe - a Case Study of the Noubi Fault Zone -

    NASA Astrophysics Data System (ADS)

    Kuriyama, M.; Kumamoto, T.; Fujita, M.

    2005-12-01

    propagation. Moreover, it was clarified that the horizontal velocities by assuming the cascade model was underestimated more than one standard deviation of empirical relation by Si and Midorikawa (1999). The scaling and cascade models showed an approximately 6.4-fold difference for the case, in which the rupture started along the southeastern edge of the Umehara Fault at observation point GIF020. This difference is significantly large in comparison with the effect of different rupture starting points, and shows that it is important to base scenario earthquake assumptions on active fault datasets before establishing the source characterization model. The distribution map of seismic intensity for the 1891 Noubi Earthquake also suggests that the synthetic waveforms in the southeastern Noubi Fault zone may be underestimated. Our results indicate that outer fault parameters (e.g., earthquake moment) related to the construction of scenario earthquakes influence strong motion prediction, rather than inner fault parameters such as the rupture starting point. Based on these methods, we will predict strong motion for approximately 140 to 150 km of the Itoigawa-Shizuoka Tectonic Line.

  11. Regulation of yeast DNA polymerase δ-mediated strand displacement synthesis by 5'-flaps.

    PubMed

    Koc, Katrina N; Stodola, Joseph L; Burgers, Peter M; Galletto, Roberto

    2015-04-30

    The strand displacement activity of DNA polymerase δ is strongly stimulated by its interaction with proliferating cell nuclear antigen (PCNA). However, inactivation of the 3'-5' exonuclease activity is sufficient to allow the polymerase to carry out strand displacement even in the absence of PCNA. We have examined in vitro the basic biochemical properties that allow Pol δ-exo(-) to carry out strand displacement synthesis and discovered that it is regulated by the 5'-flaps in the DNA strand to be displaced. Under conditions where Pol δ carries out strand displacement synthesis, the presence of long 5'-flaps or addition in trans of ssDNA suppress this activity. This suggests the presence of a secondary DNA binding site on the enzyme that is responsible for modulation of strand displacement activity. The inhibitory effect of a long 5'-flap can be suppressed by its interaction with single-stranded DNA binding proteins. However, this relief of flap-inhibition does not simply originate from binding of Replication Protein A to the flap and sequestering it. Interaction of Pol δ with PCNA eliminates flap-mediated inhibition of strand displacement synthesis by masking the secondary DNA site on the polymerase. These data suggest that in addition to enhancing the processivity of the polymerase PCNA is an allosteric modulator of other Pol δ activities.

  12. Peak muscle activation, joint kinematics, and kinetics during elliptical and stepping movement pattern on a Precor Adaptive Motion Trainer.

    PubMed

    Rogatzki, Matthew J; Kernozek, Thomas W; Willson, John D; Greany, John F; Hong, Di-An; Porcari, John R

    2012-06-01

    Kinematic, kinetic, and electromyography data were collected from the biceps femoris, rectus femoris (RF), gluteus maximus, and erector spinae (ES) during a step and elliptical exercise at a standardized workload with no hand use. Findings depicted 95% greater ankle plantar flexion (p = .01), 29% more knee extension (p = .003), 101% higher peak knee flexor moments (p < .001) 54% greater hip extensor moments (p < .001), 268% greater anterior joint reaction force (p = .009), 37% more RF activation (p < .001), and 200 % more ES activation (p <. 001) for the elliptical motion. Sixteen percent more hip flexion (p < .001), 42% higher knee extensor moments (p < .001), and 54% greater hip flexor moments (p = .041) occurred during the step motion. Biomechanical differences between motions should be considered when planning an exercise regimen. PMID:22808700

  13. Cortical activation to object shape and speed of motion during the first year

    PubMed Central

    Wilcox, Teresa; Hawkins, Laura B.; Hirskkowitz, Amy; Boas, David A.

    2014-01-01

    A great deal is known about the functional organization of cortical networks that mediate visual object processing in the adult. The current research is part of a growing effort to identify the functional maturation of these pathways in the developing brain. The current research used near-infrared spectroscopy to investigate functional activation of the infant cortex during the processing of featural information (shape) and spatiotemporal information (speed of motion) during the first year of life. Our investigation focused on two areas that were implicated in previous studies: anterior temporal cortex and posterior parietal cortex. Neuroimaging data were collected with 207 infants across three age groups: 3 to 6 months (Experiment 1), 7 to 8 months (Experiment 2), and 10 to 12 months (Experiments 3 and 4). The neuroimaging data revealed age-related changes in patterns of activation to shape and speed information, mostly involving posterior parietal areas, some of which were predicted and others that were not. We suggest that these changes reflect age-related differences in the perceptual and/or cognitive processes engaged during the task. PMID:24821531

  14. Active knee range of motion assessment in elite track and field athletes: normative values

    PubMed Central

    Malliaropoulos, Nikos; Kakoura, Lena; Tsitas, Kostas; Christodoulou, Dimitris; Siozos, Alexandros; Malliaras, Peter; Maffulli, Nicola

    2015-01-01

    Summary Background flexibility is an important physical characteristic in athletes in terms of performance and injury prevention. Active Range Of Motion (AROM) was assessed in elite Greek track and field athletes. Methods prospective cohort study was carried out. In the period 2000–2010, the AROM was measured bilaterally with the Active Knee Extension (AKE) test during an in-season period with a goniometer in 127 athletes. Results male runners and jumpers had a higher mean AROM than throwers, but this result was not statistically significant. Female jumpers had a higher mean AROM than both runners and throwers, but the difference was also not statistically significant. Conclusion in athletes, mean posterior thigh muscle flexibility is likely to be between 72.3° and 73.9°. Posterior thigh muscle flexibility is associated with performance, the higher the AROM, the better performance is achieved athletes have generally high AROM, and this may be a result of their increased muscle flexibility. The normative values of posterior thigh flexibility may assist in better monitoring rehabilitation of the posterior thigh muscle injuries and be useful in pre-season screening of athletes’ flexibility. PMID:26605196

  15. Evolution of muscle activity patterns driving motions of the jaw and hyoid during chewing in Gnathostomes.

    PubMed

    Konow, Nicolai; Herrel, Anthony; Ross, Callum F; Williams, Susan H; German, Rebecca Z; Sanford, Christopher P J; Gintof, Chris

    2011-08-01

    Although chewing has been suggested to be a basal gnathostome trait retained in most major vertebrate lineages, it has not been studied broadly and comparatively across vertebrates. To redress this imbalance, we recorded EMG from muscles powering anteroposterior movement of the hyoid, and dorsoventral movement of the mandibular jaw during chewing. We compared muscle activity patterns (MAP) during chewing in jawed vertebrate taxa belonging to unrelated groups of basal bony fishes and artiodactyl mammals. Our aim was to outline the evolution of coordination in MAP. Comparisons of activity in muscles of the jaw and hyoid that power chewing in closely related artiodactyls using cross-correlation analyses identified reorganizations of jaw and hyoid MAP between herbivores and omnivores. EMG data from basal bony fishes revealed a tighter coordination of jaw and hyoid MAP during chewing than seen in artiodactyls. Across this broad phylogenetic range, there have been major structural reorganizations, including a reduction of the bony hyoid suspension, which is robust in fishes, to the acquisition in a mammalian ancestor of a muscle sling suspending the hyoid. These changes appear to be reflected in a shift in chewing MAP that occurred in an unidentified anamniote stem-lineage. This shift matches observations that, when compared with fishes, the pattern of hyoid motion in tetrapods is reversed and also time-shifted relative to the pattern of jaw movement.

  16. Refining the intrinsic chimera flap: a review.

    PubMed

    Agarwal, Jayant P; Agarwal, Shailesh; Adler, Neta; Gottlieb, Lawrence J

    2009-10-01

    Reconstruction of complex tissue deficiencies in which each missing component is in a different spatial relationship to each other can be particularly challenging, especially in patients with limited recipient vessels. The chimera flap design is uniquely suited to reconstruct these deformities. Chimera flaps have been previously defined in many ways with 2 main categories: prefabricated or intrinsic. Herein we attempt to clarify the definition of a true intrinsic chimeric flap and provide examples of how these constructs provide a method for reconstruction of complex defects. The versatility of the intrinsic chimera flap and its procurement from 7 different vascular systems is described. A clarification of the definition of a true intrinsic chimera flap is described. In addition, construction of flaps from the lateral femoral circumflex, deep circumflex iliac, inferior gluteal, peroneal, subscapular, thoracodorsal, and radial arterial systems is described to showcase the versatility of these chimera flaps. A true intrinsic chimera flap must consist of more than a single tissue type. Each of the tissue components receives its blood flow from separate vascular branches or perforators that are connected to a single vascular source. These vascular branches must be of appropriate length to allow for insetting with 3-dimensional spatial freedom. There are a multitude of sites from which true intrinsic chimera flaps may be harvested.

  17. Pressure Available for Cooling with Cowling Flaps

    NASA Technical Reports Server (NTRS)

    Stickle, George W; Naiman, Irven; Crigler, John L

    1941-01-01

    Report presents the results of a full-scale investigation conducted in the NACA 20-foot tunnel to determine the pressure difference available for cooling with cowling flaps. The flaps were applied to an exit slot of smooth contour at 0 degree flap angle. Flap angles of 0 degree, 15 degrees, and 30 degrees were tested. Two propellers were used; propeller c which has conventional round blade shanks and propeller f which has airfoil sections extending closer to the hub. The pressure available for cooling is shown to be a direct function of the thrust disk-loading coefficient of the propeller.

  18. Basic Perforator Flap Hemodynamic Mathematical Model

    PubMed Central

    Tao, Youlun; Ding, Maochao; Wang, Aiguo; Zhuang, Yuehong; Chang, Shi-Min; Mei, Jin; Hallock, Geoffrey G.

    2016-01-01

    Background: A mathematical model to help explain the hemodynamic characteristics of perforator flaps based on blood flow resistance systems within the flap will serve as a theoretical guide for the future study and clinical applications of these flaps. Methods: There are 3 major blood flow resistance network systems of a perforator flap. These were defined as the blood flow resistance of an anastomosis between artery and artery of adjacent perforasomes, between artery and vein within a perforasome, and then between vein and vein corresponding to the outflow of that perforasome. From this, a calculation could be made of the number of such blood flow resistance network systems that must be crossed for all perforasomes within a perforator flap to predict whether that arrangement would be viable. Results: The summation of blood flow resistance networks from each perforasome in a given perforator flap could predict which portions would likely survive. This mathematical model shows how this is directly dependent on the location of the vascular pedicle to the flap and whether supercharging or superdrainage maneuvers have been added. These configurations will give an estimate of the hemodynamic characteristics for the given flap design. Conclusions: This basic mathematical model can (1) conveniently determine the degree of difficulty for each perforasome within a perforator flap to survive; (2) semiquantitatively allow the calculation of basic hemodynamic parameters; and (3) allow the assessment of the pros and cons expected for each pattern of perforasomes encountered clinically based on predictable hemodynamic observations. PMID:27579238

  19. Arterialized Venous Bone Flaps: An Experimental Investigation

    PubMed Central

    Borumandi, Farzad; Higgins, James P.; Buerger, Heinz; Vasilyeva, Anna; Benlidayi, Memmet Emre; Sencar, Leman; Gaggl, Alexander

    2016-01-01

    In arterialized venous flaps (AVFs) the venous network is used to revascularize the flap. While the feasibility of AVFs in soft tissues has been reported there is no study on osseous AVFs. In this study we aim to assess the flap survival of osseous AVFs in a pig model. Medial femoral condyle flaps were elevated in 18 pigs. Three groups were created: AVF (n = 6), conventional arterial flap (cAF, n = 6) and bone graft (BG, n = 6). The AVFs were created by anastomosis of genicular artery with one vena comitans while leaving one efferent vein for drainage. After 6 months the specimens were harvested. The histology and histomorphometry of of the bone in cAF and AVF was significantly superior to bone grafts with a higher bone volume in AVFs (p = 0.01). This study demonstrates that osseous free flaps may be supported and survive using the technique of arterialization of the venous network. The concept of AVFs in osseous flaps may be feasible for revascularization of free flaps with an inadequate artery but well developed veins. Further experimental and clinical studies are needed to assess the feasibility of clinical use of arterialized venous bone flaps. PMID:27558705

  20. Numerical and experimental investigations on unsteady aerodynamics of flapping wings

    NASA Astrophysics Data System (ADS)

    Yu, Meilin

    the flow fields around a series of plunging NACA symmetric airfoils with thickness ratio ranging from 4.0% to 20.0% of the airfoil chord length. The contribution of viscous force to flapping propulsion is accessed and it is found that viscous force becomes thrust producing, instead of drag producing, and plays a non-negligible role in thrust generation for thin airfoils. This is closely related to the variations of the dynamics of the unsteady vortex structures around the plunging airfoils. As nature flyers use complex wing kinematics in flapping flight, kinematics effects on the aerodynamic performance with different airfoil thicknesses are numerically studied by using a series of NACA symmetric airfoils. It is found that the combined plunging and pitching motion can outperform the pure plunging or pitching motion by sophisticatedly adjusting the airfoil gestures during the oscillation stroke. The thin airfoil better manipulates leading edge vortices (LEVs) than the thick airfoil (NACA0030) does in studied cases, and there exists an optimal thickness for large thrust generation with reasonable propulsive efficiency. With the present kinematics and dynamic parameters, relatively low reduced frequency is conducive for thrust production and propulsive efficiency for all tested airfoil thicknesses. In order to obtain the optimal kinematics parameters of flapping flight, a kinematics optimization is then performed. A gradient-based optimization algorithm is coupled with a second-order SD Navier-Stokes solver to search for the optimal kinematics of a certain airfoil undergoing a combined plunging and pitching motion. Then a high-order SD scheme is used to verify the optimization results and reveal the detailed vortex structures associated with the optimal kinematics of the flapping flight. It is found that for the case with maximum propulsive efficiency, there exists no leading edge separation during most of the oscillation cycle. In order to provide constructive

  1. The need for higher-order averaging in the stability analysis of hovering, flapping-wing flight.

    PubMed

    Taha, Haithem E; Tahmasian, Sevak; Woolsey, Craig A; Nayfeh, Ali H; Hajj, Muhammad R

    2015-01-05

    Because of the relatively high flapping frequency associated with hovering insects and flapping wing micro-air vehicles (FWMAVs), dynamic stability analysis typically involves direct averaging of the time-periodic dynamics over a flapping cycle. However, direct application of the averaging theorem may lead to false conclusions about the dynamics and stability of hovering insects and FWMAVs. Higher-order averaging techniques may be needed to understand the dynamics of flapping wing flight and to analyze its stability. We use second-order averaging to analyze the hovering dynamics of five insects in response to high-amplitude, high-frequency, periodic wing motion. We discuss the applicability of direct averaging versus second-order averaging for these insects.

  2. Repair of Posterior Glottic Stenosis with the Modified Endoscopic Postcricoid Advancement Flap.

    PubMed

    Damrose, Edward J; Beswick, Daniel M

    2016-03-01

    Posterior glottic stenosis is a difficult clinical problem that frequently results in bilateral vocal fold immobility, dyspnea, and tracheostomy dependence. Charts were reviewed of all patients undergoing a modified endoscopic postcricoid advancement flap procedure for posterior glottic stenosis between October 1, 2003, and June 30, 2015. Age, sex, operative findings, complications, and outcomes were noted. Follow-up was available in 10 of 11 patients, 10 of whom were successfully decannulated. There were no complications. Regular diet was maintained in all patients. In patients with bilateral vocal fold immobility secondary to posterior glottis stenosis, endoscopic repair via endoscopic postcricoid advancement flap can restore full vocal fold motion and allow decannulation. In select patients with posterior glottic stenosis, repair via endoscopic postcricoid advancement flap should be considered in lieu of ablative methods, such as cordotomy, cordectomy, or arytenoidectomy. PMID:26861233

  3. Excitation, response, and fatigue life estimation methods for the structural design of externally blown flaps

    NASA Technical Reports Server (NTRS)

    Ungar, E. E.; Chandiramani, K. L.; Barger, J. E.

    1972-01-01

    Means for predicting the fluctuating pressures acting on externally blown flap surfaces are developed on the basis of generalizations derived from non-dimensionalized empirical data. Approaches for estimation of the fatigue lives of skin-stringer and honeycomb-core sandwich flap structures are derived from vibration response analyses and panel fatigue data. Approximate expressions for fluctuating pressures, structural response, and fatigue life are combined to reveal the important parametric dependences. The two-dimensional equations of motion of multi-element flap systems are derived in general form, so that they can be specialized readily for any particular system. An introduction is presented of an approach to characterizing the excitation pressures and structural responses which makes use of space-time spectral concepts and promises to provide useful insights, as well as experimental and analytical savings.

  4. The mechanism of body rotation in the flapping flight of butterflies

    NASA Astrophysics Data System (ADS)

    Fei, Yueh-Han; Yang, Jing-Tang

    2013-11-01

    The aerodynamic effects of the body rotation on the flapping flying of butterflies are experimentally and numerically investigated. We first observe and record the flying motion of a butterfly (Kallima inachus) in free flight, focusing especially on the body rotation, via two high speed video cameras and PIV. The body rotation is found in phase with wing flapping while the abdomen is out of phase with wing flapping. Further, we establish the model of flexible wings of a butterfly and exploit the fluid dynamics analysis via the dynamic mesh technique to study the contribution of body rotation to the lift. The results reveal that the body rotation is capable of strengthening the vortex ring structure and correspondingly enhancing the efficiency of lift production. Our simulation model shows the body rotation contributes 15% of total lift. The results of this study may serve as a useful guide for designing insect-like MAVs in the future.

  5. Initial piloted simulation study of geared flap control for tilt-wing V/STOL aircraft

    NASA Technical Reports Server (NTRS)

    Guerrero, Lourdes M.; Corliss, Lloyd D.

    1991-01-01

    A simulation study of a representative tilt wing transport aircraft was conducted in 1990 on the Ames Vertical Motion Simulator. This simulation is in response to renewed interest in the tilt wing concept for use in future military and civil applications. For past tilt wing concepts, pitch control in hover and low-speed flight has required a tail rotor or reaction jets at the tail. Use of mono cyclic propellers or a geared flap have also been proposed as alternate methods for providing pitch control at low speed. The geared flap is a subject of this current study. This report describes the geared flap concept, the tilt wing aircraft, the simulation model, the simulation facility and experiment setup, the pilots' evaluation tasks and procedures, and the results obtained from the simulation experiment. The pilot evaluations and comments are also documented in the report appendix.

  6. Experiments on the motion of gas bubbles in turbulence generated by an active grid

    NASA Astrophysics Data System (ADS)

    Poorte, R. E. G.; Biesheuvel, A.

    2002-06-01

    The random motion of nearly spherical bubbles in the turbulent flow behind a grid is studied experimentally. In quiescent water these bubbles rise at high Reynolds number. The turbulence is generated by an active grid of the design of Makita (1991), and can have turbulence Reynolds number R[lambda] of up to 200. Minor changes in the geometry of the grid and in its mode of operation improves the isotropy of the turbulence, compared with that reported by Makita (1991) and Mydlarski & Warhaft (1996). The trajectory of each bubble is measured with high spatial and temporal resolution with a specially developed technique that makes use of a position-sensitive detector. Bubble statistics such as the mean rise velocity and the root-mean-square velocity fluctuations are obtained by ensemble averaging over many identical bubbles. The resulting bubble mean rise velocity is significantly reduced (up to 35%) compared with the quiescent conditions. The vertical bubble velocity fluctuations are found to be non-Gaussian, whereas the horizontal displacements are Gaussian for all times. The diffusivity of bubbles is considerably less than that of fluid particles. These findings are qualitatively consistent with results obtained through theoretical analysis and numerical simulations by Spelt & Biesheuvel (1997).

  7. A framework for activity detection in wide-area motion imagery

    SciTech Connect

    Porter, Reid B; Ruggiero, Christy E; Morrison, Jack D

    2009-01-01

    Wide-area persistent imaging systems are becoming increasingly cost effective and now large areas of the earth can be imaged at relatively high frame rates (1-2 fps). The efficient exploitation of the large geo-spatial-temporal datasets produced by these systems poses significant technical challenges for image and video analysis and data mining. In recent years there has been significant progress made on stabilization, moving object detection and tracking and automated systems now generate hundreds to thousands of vehicle tracks from raw data, with little human intervention. However, the tracking performance at this scale, is unreliable and average track length is much smaller than the average vehicle route. This is a limiting factor for applications which depend heavily on track identity, i.e. tracking vehicles from their points of origin to their final destination. In this paper we propose and investigate a framework for wide-area motion imagery (W AMI) exploitation that minimizes the dependence on track identity. In its current form this framework takes noisy, incomplete moving object detection tracks as input, and produces a small set of activities (e.g. multi-vehicle meetings) as output. The framework can be used to focus and direct human users and additional computation, and suggests a path towards high-level content extraction by learning from the human-in-the-loop.

  8. Field-Aligned Current Sheet Motion and Its Correlation with Solar Wind Conditions and Geomagnetic Activities

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Le, G.; Boardsen, S. A.; Slavin, J. A.; Strangeway, R. J.

    2008-05-01

    Field-aligned currents (FACs) are the currents flowing into and out of the ionosphere which connect to the magnetosphere. They provide an essential linkage between the solar wind - magnetosphere system and the ionosphere, and the understanding of these currents is important for global magnetosphere dynamics and space weather prediction. The three spacecraft ST-5 constellation provides an unprecedented opportunity to study in situ FAC dynamics in time scales (10 sec to 10 min) that can not be achieved previously with single spacecraft studies or large-spaced conjugate spacecraft studies. In this study, we use the magnetic field observations during the whole ST-5 mission and their corresponding solar wind conditions to study the dependence of FAC current sheet motion and intensity on solar wind conditions. FAC peak current densities show very good correlations with some solar wind parameters, including IMF Bz, dynamic pressure, Ey, and some IMF angles, but not with other parameters. Instant FAC speeds show generally much weaker dependence on solar wind conditions comparing to FAC peak current densities. This obvious uncorrelation between FAC peak current densities and speeds implies that FAC peak current densities are more consistently controlled by solar wind conditions and geomagnetic activities, while FAC speeds are more oscillatory, sometimes with higher speeds during quieter times and lower speeds during more turbulent times.

  9. THE CHROMOSPHERIC ACTIVITY, AGE, METALLICITY, AND SPACE MOTIONS OF 36 WIDE BINARIES

    SciTech Connect

    Zhao, J. K.; Oswalt, T. D.; Rudkin, M.; Zhao, G.; Chen, Y. Q. E-mail: toswalt@fit.edu E-mail: gzhao@bao.ac.cn

    2011-04-15

    We present the chromospheric activity (CA) levels, metallicities, and full space motions for 41 F, G, K, and M dwarf stars in 36 wide binary systems. Thirty-one of the binaries contain a white dwarf (WD) component. In such binaries, the total age can be estimated by adding the cooling age of the WD to an estimate of the progenitor's main-sequence lifetime. To better understand how CA correlates to stellar age, 14 cluster member stars were also observed. Our observations demonstrate for the first time that, in general, CA decays with age from 50 Myr to at least 8 Gyr for stars with 1.0 {<=} V - I {<=} 2.4. However, little change occurs in the CA level for stars with V - I < 1.0 between 1 Gyr and 5 Gyr, consistent with the results of Pace et al. Our sample also exhibits a negative correlation between the stellar age and metallicity, a positive correlation between the stellar age and W space velocity component, and the W velocity dispersion increases with age. Finally, the population membership of these wide binaries is examined based upon their U, V, W kinematics, metallicity, and CA. We conclude that wide binaries are similar to field and cluster stars in these respects. More importantly, they span a much more continuous range in age and metallicity than is afforded by nearby clusters.

  10. Noise-enhanced stability and double stochastic resonance of active Brownian motion

    NASA Astrophysics Data System (ADS)

    Zeng, Chunhua; Zhang, Chun; Zeng, Jiakui; Liu, Ruifen; Wang, Hua

    2015-08-01

    In this paper, we study the transient and resonant properties of active Brownian particles (ABPs) in the Rayleigh-Helmholtz (RH) and Schweitzer-Ebeling-Tilch (SET) models, which is driven by the simultaneous action of multiplicative and additive noise and periodic forcing. It is shown that the cross-correlation between two noises (λ) can break the symmetry of the potential to generate motion of the ABPs. In case of no correlation between two noises, the mean first passage time (MFPT) is a monotonic decrease depending on the multiplicative noise, however in case of correlation between two noises, the MFPT exhibits a maximum, depending on the multiplicative noise for both models, this maximum for MFPT identifies the noise-enhanced stability (NES) effect of the ABPs. By comparing with case of no correlation (λ =0.0 ), we find two maxima in the signal-to-noise ratio (SNR) depending on the cross-correlation intensity, i.e. the double stochastic resonance is shown in both models. For the RH model, the SNR exhibits two maxima depending on the multiplicative noise for small cross-correlation intensity, while in the SET model, it exhibits only a maximum depending on the multiplicative noise. Whether λ =0.0 or not, the MFPT is a monotonic decrease, and the SNR exhibits a maximum, depending on the additive noise in both models.

  11. Fabric Active Transducer Stimulated by Water Motion for Self-Powered Wearable Device.

    PubMed

    Kwon, Soon-Hyung; Kim, Won Keun; Park, Junwoo; Yang, YoungJun; Yoo, Byungwook; Han, Chul Jong; Kim, Youn Sang

    2016-09-21

    The recent trend of energy-harvesting devices is an adoption of fabric materials with flexible and stretchable according to the increase of wearable electronics. But it is a difficult process to form a core structure of dielectric layer or electrode on fabric materials. In particular, a fabric-based energy-harvesting device in contact with water has not been studied, though there are many challenging issues including insulation and water absorption in a harsh environment. So we propose an effective method to obtain an electrical energy from the water contact using our new fabric energy harvesting device. Our water motion active transducer (WMAT) is designed to obtain electrical energy from the variable capacitance through the movement and contact of water droplet. In this paper, we succeeded in generating an electrical energy with peak to peak power of 280 μW using a 30 μL of water droplet with the fabric WMAT device of 70 mm × 50 mm dimension. Furthermore, we specially carried out spray-coating and transfer processes instead of the conventional spin-coating process on fabric materials to overcome the limitation of its uneven morphology and porous and deformable assembly. PMID:27564593

  12. Personalized Multilayer Daily Life Profiling Through Context Enabled Activity Classification and Motion Reconstruction: An Integrated System Approach.

    PubMed

    Xu, James Y; Wang, Yan; Barrett, Mick; Dobkin, Bruce; Pottie, Greg J; Kaiser, William J

    2016-01-01

    Profiling the daily activity of a physically disabled person in the community would enable healthcare professionals to monitor the type, quantity, and quality of their patients' compliance with recommendations for exercise, fitness, and practice of skilled movements, as well as enable feedback about performance in real-world situations. Based on our early research in in-community activity profiling, we present in this paper an end-to-end system capable of reporting a patient's daily activity at multiple levels of granularity: 1) at the highest level, information on the location categories a patient is able to visit; 2) within each location category, information on the activities a patient is able to perform; and 3) at the lowest level, motion trajectory, visualization, and metrics computation of each activity. Our methodology is built upon a physical activity prescription model coupled with MEMS inertial sensors and mobile device kits that can be sent to a patient at home. A novel context-guided activity-monitoring concept with categorical location context is used to achieve enhanced classification accuracy and throughput. The methodology is then seamlessly integrated with motion reconstruction and metrics computation to provide comprehensive layered reporting of a patient's daily life. We also present an implementation of the methodology featuring a novel location context detection algorithm using WiFi augmented GPS and overlays, with motion reconstruction and visualization algorithms for practical in-community deployment. Finally, we use a series of experimental field evaluations to confirm the accuracy of the system. PMID:25546868

  13. Personalized Multilayer Daily Life Profiling Through Context Enabled Activity Classification and Motion Reconstruction: An Integrated System Approach.

    PubMed

    Xu, James Y; Wang, Yan; Barrett, Mick; Dobkin, Bruce; Pottie, Greg J; Kaiser, William J

    2016-01-01

    Profiling the daily activity of a physically disabled person in the community would enable healthcare professionals to monitor the type, quantity, and quality of their patients' compliance with recommendations for exercise, fitness, and practice of skilled movements, as well as enable feedback about performance in real-world situations. Based on our early research in in-community activity profiling, we present in this paper an end-to-end system capable of reporting a patient's daily activity at multiple levels of granularity: 1) at the highest level, information on the location categories a patient is able to visit; 2) within each location category, information on the activities a patient is able to perform; and 3) at the lowest level, motion trajectory, visualization, and metrics computation of each activity. Our methodology is built upon a physical activity prescription model coupled with MEMS inertial sensors and mobile device kits that can be sent to a patient at home. A novel context-guided activity-monitoring concept with categorical location context is used to achieve enhanced classification accuracy and throughput. The methodology is then seamlessly integrated with motion reconstruction and metrics computation to provide comprehensive layered reporting of a patient's daily life. We also present an implementation of the methodology featuring a novel location context detection algorithm using WiFi augmented GPS and overlays, with motion reconstruction and visualization algorithms for practical in-community deployment. Finally, we use a series of experimental field evaluations to confirm the accuracy of the system.

  14. The vascularized periosteum flap as novel tissue engineering model for repair of cartilage defects

    PubMed Central

    Harhaus, Leila; Huang, Jung-Ju; Kao, Shu-Wei; Wu, Yen-Lin; Mackert, Gina Alicia; Höner, Bernd; Cheng, Ming-Huei; Kneser, Ulrich; Cheng, Chao-Min

    2015-01-01

    Periosteum is a promising tissue engineering scaffold in research of cartilage repair; so far however, periosteum transfers have not been realized successfully because of insufficient nourishment of the graft. In a translational approach we, for the first time, designed a vascularized periosteum flap as ‘independent’ biomaterial with its own blood supply to address this problem and to reconstruct circumscript cartilage defects. In six 3-month-old New Zealand rabbits, a critical size cartilage defect of the medial femur condyle was created and covered by a vascularized periosteum flap pedicled on the saphenous vessels. After 28 days, formation of newly built cartilage was assessed macroscopically, histologically and qualitatively via biomechanical compression testing, as well as on molecular biological level via immunohistochemistry. All wounds healed completely, all joints were stable and had full range of motion. All flaps survived and were perfused through their pulsating pedicles. They showed a stable attachment to the bone, although partially incomplete adherence. Hyaline cartilage with typical columnar cell distribution and positive Collagen II staining was formed in the transferred flaps. Biomechanical testing revealed a significantly higher maximum load than the positive control, but a low elasticity. This study proved that vascularization of the periosteum flap is the essential step for flap survival and enables the flap to transform into cartilage. Reconstruction of circumscript cartilage defects seems to be possible. Although these are the first results out of a pilot project, this technique, we believe, can have a wide range of potential applications and high relevance in the clinical field. PMID:25754287

  15. Extremely reduced motion in front of screens: investigating real-world physical activity of adolescents by accelerometry and electronic diary.

    PubMed

    Streb, Judith; Kammer, Thomas; Spitzer, Manfred; Hille, Katrin

    2015-01-01

    This paper reports accelerometer and electronic dairy data on typical daily activities of 139 school students from grade six and nine. Recordings covered a typical school day for each student and lasted on average for 23 h. Screen activities (watching television and using the computer) are compared to several other activities performed while sitting (e.g., playing, eating, sitting in school, and doing homework). Body movement was continuously recorded by four accelerometers and transformed into a motion sore. Our results show that extremely low motion scores, as if subjects were freezing, emerge to a greater extent in front of screens compared to other investigated activities. Given the substantial amount of time young people spend in front of screens and the rising obesity epidemic, our data suggest a mechanism for the association of screen time and obesity. PMID:25955531

  16. Oak Ridge National Laboratory's (ORNL) Weigh-In-Motion (WIM) Configuration and Data Management Activities

    SciTech Connect

    Abercrombie, Robert K; Sheldon, Frederick T; Schlicher, Bob G

    2006-01-01

    The Oak Ridge National Laboratory (ORNL) involvement in the Weigh-in-Motion (WIM) research with both government agencies and private companies dates back to 1989. The discussion here will focus on the US Army's current need for an automated WIM system to weigh and determine the center-of-balance for military wheeled vehicles and cargo and the expanded uses of WIM data. ORNL is addressing configuration and data management issues as they relate to deployments for both military and humanitarian activities. The transition from the previous WIM Gen I to the current Gen II system illustrates a configuration and data management solution that ensures data integration, integrity, coherence and cost effectiveness. Currently, Army units use portable and fixed scales, tape measures, and calculators to determine vehicle axle, total weights and center of balance for vehicles prior to being transshipped via railcar, ship, or airlifted. Manually weighing and measuring all vehicles subject to these transshipment operations is time-consuming, labor-intensive, hazardous and is prone to human errors (e.g., misreading scales and tape measures, calculating centers of balance and wheel, axle, and vehicle weights, recording data, and transferring data from manually prepared work sheets into an electronic data base and aggravated by adverse weather conditions). Additionally, in the context of the military, the timeliness, safety, success, and effectiveness of airborne heavy-drop operations can be significantly improved by the use of an automated system to weigh and determine center of balance of vehicles while they are in motion. The lack of a standardized airlift-weighing system for joint service use also creates redundant weighing requirements at the cost of scarce resources and time. This case study can be judiciously expanded into commercial operations related to safety and enforcement. The WIM program will provide a means for the Army to automatically identify/weigh and monitor

  17. Unraveling HIV protease flaps dynamics by Constant pH Molecular Dynamics simulations.

    PubMed

    Soares, Rosemberg O; Torres, Pedro H M; da Silva, Manuela L; Pascutti, Pedro G

    2016-08-01

    The active site of HIV protease (HIV-PR) is covered by two flaps. These flaps are known to be essential for the catalytic activity of the HIV-PR, but their exact conformations at the different stages of the enzymatic pathway remain subject to debate. Understanding the correct functional dynamics of the flaps might aid the development of new HIV-PR inhibitors. It is known that, the HIV-PR catalytic efficiency is pH-dependent, likely due to the influence of processes such as charge transfer and protonation/deprotonation of ionizable residues. Several Molecular Dynamics (MD) simulations have reported information about the HIV-PR flaps. However, in MD simulations the protonation of a residue is fixed and thus it is not possible to study the correlation between conformation and protonation state. To address this shortcoming, this work attempts to capture, through Constant pH Molecular Dynamics (CpHMD), the conformations of the apo, substrate-bound and inhibitor-bound HIV-PR, which differ drastically in their flap arrangements. The results show that the HIV-PR flaps conformations are defined by the protonation of the catalytic residues Asp25/Asp25' and that these residues are sensitive to pH changes. This study suggests that the catalytic aspartates can modulate the opening of the active site and substrate binding. PMID:27291071

  18. [The super extended sub-mental flap or combo sub-mental flap].

    PubMed

    Martin, D

    2014-08-01

    The author presents a technical variation of the sub-mental flap including in a conventional pedicled flap both sub-mental axes and their anastomoses on the midline. The assessment of the first flaps raised according to this method confirms the improvement of the distal blood supply. It allows the possibility to harvest "super extended" flaps reaching the contralateral auricular lobula. This variation can be considered as an axial flap which only the tip, located beyond the mandibular angle, is at random. The evolution of the sub-mental flap from its original description to this variation called "combo sub-mental flap" is then presented. Its reliability and the technical simplification it provides will have to be assessed in the future. PMID:24840945

  19. Motion patterns in activities of daily living: 3- year longitudinal follow-up after total shoulder arthroplasty using an optical 3D motion analysis system

    PubMed Central

    2014-01-01

    Background Total shoulder arthroplasty (TSA) can improve function in osteoarthritic shoulders, but the ability to perform activities of daily living (ADLs) can still remain impaired. Routinely, shoulder surgeons measure range of motion (ROM) using a goniometer. Objective data are limited, however, concerning functional three-dimensional changes in ROM in ADLs after TSA in patients with degenerative glenohumeral osteoarthritis. Methods This study included ten consecutive patients, who received TSA for primary glenohumeral osteoarthritis. The patients were examined the day before, 6 months, and 3 years after shoulder replacement as well. We compared them with a control group (n = 10) without any shoulder pathology and measured shoulder movement by 3D motion analysis using a novel 3 D model. The measurement included static maximum values, the ability to perform and the ROM of the ADLs “combing the hair”, “washing the opposite armpit”, “tying an apron”, and “taking a book from a shelf”. Results Six months after surgery, almost all TSA patients were able to perform the four ADLs (3 out of 40 tasks could not be performed by the 10 patients); 3 years postoperatively all patients were able to carry out all ADLs (40 out of 40 tasks possible). In performing the ADLs, comparison of the pre- with the 6-month and 3-year postoperative status of the TSA group showed that the subjects did not fully use the available maximum flexion/extension ROM in performing the four ADLs. The ROM used for flexion/extension did not change significantly (preoperatively 135°-0° -34° vs. 3 years postoperatively 131° -0° -53°). For abduction/adduction, ROM improved significantly from 33°-0° -27° preoperatively to 76° -0° -35° postoperatively. Compared to the controls (118°) the TSA group used less ROM for abduction to perform the four ADLs 3 years postoperatively. Conclusion TSA improves the ability to perform ADL and the individual ROM in ADLs in patients with

  20. MOJAVE. X. PARSEC-SCALE JET ORIENTATION VARIATIONS AND SUPERLUMINAL MOTION IN ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Lister, M. L.; Richards, J. L.; Aller, M. F.; Aller, H. D.; Homan, D. C.; Kellermann, K. I.; Kovalev, Y. Y.

    2013-11-01

    We describe the parsec-scale kinematics of 200 active galactic nucleus (AGN) jets based on 15 GHz Very Long Baseline Array (VLBA) data obtained between 1994 August 31 and 2011 May 1. We present new VLBA 15 GHz images of these and 59 additional AGNs from the MOJAVE and 2 cm Survey programs. Nearly all of the 60 most heavily observed jets show significant changes in their innermost position angle over a 12-16 yr interval, ranging from 10° to 150° on the sky, corresponding to intrinsic variations of ∼0.°5 to ∼2°. The BL Lac jets show smaller variations than quasars. Roughly half of the heavily observed jets show systematic position angle trends with time, and 20 show indications of oscillatory behavior. The time spans of the data sets are too short compared to the fitted periods (5-12 yr), however, to reliably establish periodicity. The rapid changes and large jumps in position angle seen in many cases suggest that the superluminal AGN jet features occupy only a portion of the entire jet cross section and may be energized portions of thin instability structures within the jet. We have derived vector proper motions for 887 moving features in 200 jets having at least five VLBA epochs. For 557 well-sampled features, there are sufficient data to additionally study possible accelerations. We find that the moving features are generally non-ballistic, with 70% of the well-sampled features showing either significant accelerations or non-radial motions. Inward motions are rare (2% of all features), are slow (<0.1 mas yr{sup –1}), are more prevalent in BL Lac jets, and are typically found within 1 mas of the unresolved core feature. There is a general trend of increasing apparent speed with distance down the jet for both radio galaxies and BL Lac objects. In most jets, the speeds of the features cluster around a characteristic value, yet there is a considerable dispersion in the distribution. Orientation variations within the jet cannot fully account for the

  1. MOJAVE. X. Parsec-scale Jet Orientation Variations and Superluminal Motion in Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Lister, M. L.; Aller, M. F.; Aller, H. D.; Homan, D. C.; Kellermann, K. I.; Kovalev, Y. Y.; Pushkarev, A. B.; Richards, J. L.; Ros, E.; Savolainen, T.

    2013-11-01

    We describe the parsec-scale kinematics of 200 active galactic nucleus (AGN) jets based on 15 GHz Very Long Baseline Array (VLBA) data obtained between 1994 August 31 and 2011 May 1. We present new VLBA 15 GHz images of these and 59 additional AGNs from the MOJAVE and 2 cm Survey programs. Nearly all of the 60 most heavily observed jets show significant changes in their innermost position angle over a 12-16 yr interval, ranging from 10° to 150° on the sky, corresponding to intrinsic variations of ~0.°5 to ~2°. The BL Lac jets show smaller variations than quasars. Roughly half of the heavily observed jets show systematic position angle trends with time, and 20 show indications of oscillatory behavior. The time spans of the data sets are too short compared to the fitted periods (5-12 yr), however, to reliably establish periodicity. The rapid changes and large jumps in position angle seen in many cases suggest that the superluminal AGN jet features occupy only a portion of the entire jet cross section and may be energized portions of thin instability structures within the jet. We have derived vector proper motions for 887 moving features in 200 jets having at least five VLBA epochs. For 557 well-sampled features, there are sufficient data to additionally study possible accelerations. We find that the moving features are generally non-ballistic, with 70% of the well-sampled features showing either significant accelerations or non-radial motions. Inward motions are rare (2% of all features), are slow (<0.1 mas yr-1), are more prevalent in BL Lac jets, and are typically found within 1 mas of the unresolved core feature. There is a general trend of increasing apparent speed with distance down the jet for both radio galaxies and BL Lac objects. In most jets, the speeds of the features cluster around a characteristic value, yet there is a considerable dispersion in the distribution. Orientation variations within the jet cannot fully account for the dispersion, implying

  2. Aerodynamic forces and vortical structures in flapping butterfly's forward flight

    NASA Astrophysics Data System (ADS)

    Yokoyama, Naoto; Senda, Kei; Iima, Makoto; Hirai, Norio

    2013-02-01

    Forward flights of a bilaterally symmetrically flapping butterfly modeled as a four-link rigid-body system consisting of a thorax, an abdomen, and left and right wings are numerically simulated. The joint motions of the butterflies are adopted from experimental observations. Three kinds of the simulations, distinguished by ways to determine the position and attitude of the thorax, are carried out: a tethered simulation, a prescribed simulation, and free-flight simulations. The upward and streamwise forces as well as the wake structures in the tethered simulation, where the thorax of the butterfly is fixed, reasonably agree with those in the corresponding tethered experiment. In the prescribed simulation, where the thoracic trajectories as well as the joint angles are given by those observed in a free-flight experiment, it is confirmed that the butterfly can produce enough forces to achieve the flapping flights. Moreover, coherent vortical structures in the wake and those on the wings are identified. The generation of the aerodynamic forces due to the vortical structures are also clarified. In the free-flight simulation, where only the joint angles are given as periodic functions of time, it is found that the free flight is longitudinally unstable because the butterfly cannot maintain the attitude in a proper range. Focusing on the abdominal mass, which largely varies owing to feeding and metabolizing, we have shown that the abdominal motion plays an important role in periodic flights. The necessity of control of the thoracic attitude for periodic flights and maneuverability is also discussed.

  3. Cortical activation associated with determination of depth order during transparent motion perception: A normalized integrative fMRI-MEG study.

    PubMed

    Natsukawa, Hiroaki; Kobayashi, Tetsuo

    2015-10-01

    When visual patterns drifting in different directions and/or at different speeds are superimposed on the same plane, observers perceive transparent surfaces on planes of different depths. This phenomenon is known as transparent motion perception. In this study, cortical activities were measured using functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) to reveal the cortical dynamics associated with determination of depth order during transparent motion perception. In addition, offline eye movement measurements were performed to determine the latencies of the start of both pursuit eye movements and depth attention that are important in determination of the depth order. MEG and fMRI data were analyzed by a normalized integrative fMRI-MEG method that enables reconstruction of time-varying dipole moments of activated regions from MEG signals. Statistical analysis of fMRI data was performed to identify activated regions. The activated regions were used as spatial constraints for the reconstruction using the integrative fMRI-MEG method. We focused on the period between latencies (216-405 ms) determined by eye movement experiment, which are related to determination of the depth order. The results of integrative analysis revealed that significant neural activities were observed in the visual association area, the human middle temporal area, the intraparietal sulcus, the lateral occipital cortex, and the anterior cingulate cortex between 216 and 405 ms. These results suggest that initial eye movement and accompanying cortical activations during focused duration play an important role in determining the depth order during transparent motion perception.

  4. 14 CFR 25.457 - Wing flaps.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Wing flaps. 25.457 Section 25.457 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.457 Wing flaps....

  5. 14 CFR 25.457 - Wing flaps.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Wing flaps. 25.457 Section 25.457 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.457 Wing flaps....

  6. 14 CFR 25.457 - Wing flaps.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Wing flaps. 25.457 Section 25.457 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.457 Wing flaps....

  7. 14 CFR 25.457 - Wing flaps.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Wing flaps. 25.457 Section 25.457 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.457 Wing flaps....

  8. 14 CFR 25.457 - Wing flaps.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Wing flaps. 25.457 Section 25.457 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Control Surface and System Loads § 25.457 Wing flaps....

  9. Influence of surface active substances on bubble motion and collision with various interfaces.

    PubMed

    Malysa, K; Krasowska, M; Krzan, M

    2005-06-30

    Bubble motion as a function of distance from a point of its detachment and phenomena occurring during the bubble approach and collision with liquid/gas and liquid/solid interfaces in pure water and solutions of various surface active substances are described and discussed. It is showed that presence of surface active substance has a profound influence on values of the terminal velocity and profiles of the local velocity. At low solutions concentrations there are three distinct stages in the bubble motion: (i) a rapid acceleration, (ii) a maximum velocity value followed by its monotonic decrease, and (iii) attainment of the terminal velocity, while at high concentrations (and in pure water) there are only stages (i) and (iii). It is showed that the bubble terminal velocity decreases rapidly at low surfactant concentration, but there can be found some characteristic concentrations (adsorption coverage's) above which the velocity almost stopped to decrease. Immobilization of the bubble surface resulting from adsorption of the surface active substances (surface tension gradients inducement) causes over twofold lowering of the bubble velocity. Presence of the maximum on the local velocity profiles is an indication that a stationary non-uniform distribution of adsorption coverage (needed for immobilization the bubble interface) was not established there. When the rising bubble arrives at liquid/gas interface or liquid/solid interface there can be formed either foam or wetting film or three-phase contact (TPC). It is showed that prior to the foam and/or wetting film formation the bubble colliding with the interfaces can bounce backward and simultaneously its shape pulsates rapidly with a frequency over 1000 Hz. It is rather unexpected that even in the case of the free surface the bubble's shape and consequently its surface area can vary so rapidly. It shows straightforward that on such a rapidly distorted interface the adsorption coverage can be very different from that

  10. Scrubbing noise of externally blown flaps

    NASA Technical Reports Server (NTRS)

    Fink, M. R.

    1975-01-01

    An experimental study was conducted to examine the aeroacoustic mechanism that produces externally blown flap (EBF) scrubbing noise, i.e. a surface-radiated noise which is generally strongest normal to UTW deflected flaps. Scrubbing noise was not radiated from portions of the surface adjacent to strong, locally coherent turbulent eddies. Instead, scrubbing noise seemed to come from weak loading fluctuations that were coherent along the scrubbed span. These loading fluctuations probably were induced by the convected large-scale vortex structure of the attached exhaust jet. Deflecting a UTW flap would reduce the distance between the vortex trajectory and the flap surface, increasing the resulting dipole noise and rotating its directivity. In contrast, deflecting a USB flap would increase this distance, so that observable scrubbing noise would be radiated only from the undeflected forward portion of the wing.

  11. Facial artery flaps in facial oncoplastic reconstruction.

    PubMed

    Fabrizio, Tommaso

    2013-10-01

    The face is one of the common sites for cutaneous cancer localization. It is well known that the face is the localization of more than 50% of skin cancers. Nowadays, the principles of modern "oncoplasty" recommend the complete excision of the cancer and the reconstruction with respect to cosmetic features of the face in terms of good color, good softness, and good texture of the flaps, utilized in cancer repair. The oncological and cosmetic results of facial reconstruction are strictly linked and the modern plastic and reconstructive surgeon must respect both oncological and cosmetic aspects. For that reason the best solution in facial cancer repair is the utilization of locoregional flaps based on the tributary vessels of the facial artery. In consideration of the dimension of recipient area to repair, the retroangular flap (RAF) or the submental flap could be used. This article is voted to illustrate a very large and long-term casuistry dedicated to these flaps.

  12. Modeling of flap endonuclease interactions with DNA substrate.

    PubMed

    Allawi, Hatim T; Kaiser, Michael W; Onufriev, Alexey V; Ma, Wu-Po; Brogaard, Andrew E; Case, David A; Neri, Bruce P; Lyamichev, Victor I

    2003-05-01

    Structure-specific 5' nucleases play an important role in DNA replication and repair uniquely recognizing an overlap flap DNA substrate and processing it into a DNA nick. However, in the absence of a high-resolution structure of the enzyme/DNA complex, the mechanism underlying this recognition and substrate specificity, which is key to the enzyme's function, remains unclear. Here, we propose a three-dimensional model of the structure-specific 5' flap endonuclease from Pyrococcus furiosus in its complex with DNA. The model is based on the known X-ray structure of the enzyme and a variety of biochemical and molecular dynamics (MD) data utilized in the form of distance restraints between the enzyme and the DNA. Contacts between the 5' flap endonuclease and the sugar-phosphate backbone of the overlap flap substrate were identified using enzyme activity assays on substrates with methylphosphonate or 2'-O-methyl substitutions. The enzyme footprint extends two to four base-pairs upstream and eight to nine base-pairs downstream of the cleavage site, thus covering 10-13 base-pairs of duplex DNA. The footprint data are consistent with a model in which the substrate is bound in the DNA-binding groove such that the downstream duplex interacts with the helix-hairpin-helix motif of the enzyme. MD simulations to identify the substrate orientation in this model are consistent with the results of the enzyme activity assays on the methylphosphonate and 2'-O-methyl-modified substrates. To further refine the model, 5' flap endonuclease variants with alanine point substitutions at amino acid residues expected to contact phosphates in the substrate and one deletion mutant were tested in enzyme activity assays on the methylphosphonate-modified substrates. Changes in the enzyme footprint observed for two point mutants, R64A and R94A, and for the deletion mutant in the enzyme's beta(A)/beta(B) region, were interpreted as being the result of specific interactions in the enzyme/DNA complex

  13. Flow visualization of vortices locked by spanwise blowing over wings featuring a unique leading and trailing-edge flap system

    NASA Technical Reports Server (NTRS)

    Erickson, G. E.; Campbell, J. F.

    1975-01-01

    Flow visualization studies were conducted to qualitatively determine the effects of active generation and augmentation of vortex flow over wings by blowing a discrete jet in a spanwise direction in the channel formed by extension of upper surface leading- and trailing-edge flaps. Spanwise blowing from a reflection plane over a rectangular wing was found to generate and lock a dual corotating vortex system within the channel and, at sufficient blowing rates, cause the separated flow off the upper end of the leading-edge flap to reattach to the trailing-edge flap. Test parameters included wing angle of attack, jet momentum coefficient, leading- and trailing-edge flap deflection angle, and jet location above the wing surface. Effects due to removal of the leading- and trailing-edge flap were also investigated.

  14. Personalization algorithm for real-time activity recognition using PDA, wireless motion bands, and binary decision tree.

    PubMed

    Pärkkä, Juha; Cluitmans, Luc; Ermes, Miikka

    2010-09-01

    Inactive and sedentary lifestyle is a major problem in many industrialized countries today. Automatic recognition of type of physical activity can be used to show the user the distribution of his daily activities and to motivate him into more active lifestyle. In this study, an automatic activity-recognition system consisting of wireless motion bands and a PDA is evaluated. The system classifies raw sensor data into activity types online. It uses a decision tree classifier, which has low computational cost and low battery consumption. The classifier parameters can be personalized online by performing a short bout of an activity and by telling the system which activity is being performed. Data were collected with seven volunteers during five everyday activities: lying, sitting/standing, walking, running, and cycling. The online system can detect these activities with overall 86.6% accuracy and with 94.0% accuracy after classifier personalization.

  15. DNA and Protein Requirements for Substrate Conformational Changes Necessary for Human Flap Endonuclease-1-catalyzed Reaction.

    PubMed

    Algasaier, Sana I; Exell, Jack C; Bennet, Ian A; Thompson, Mark J; Gotham, Victoria J B; Shaw, Steven J; Craggs, Timothy D; Finger, L David; Grasby, Jane A

    2016-04-01

    Human flap endonuclease-1 (hFEN1) catalyzes the essential removal of single-stranded flaps arising at DNA junctions during replication and repair processes. hFEN1 biological function must be precisely controlled, and consequently, the protein relies on a combination of protein and substrate conformational changes as a prerequisite for reaction. These include substrate bending at the duplex-duplex junction and transfer of unpaired reacting duplex end into the active site. When present, 5'-flaps are thought to thread under the helical cap, limiting reaction to flaps with free 5'-terminiin vivo Here we monitored DNA bending by FRET and DNA unpairing using 2-aminopurine exciton pair CD to determine the DNA and protein requirements for these substrate conformational changes. Binding of DNA to hFEN1 in a bent conformation occurred independently of 5'-flap accommodation and did not require active site metal ions or the presence of conserved active site residues. More stringent requirements exist for transfer of the substrate to the active site. Placement of the scissile phosphate diester in the active site required the presence of divalent metal ions, a free 5'-flap (if present), a Watson-Crick base pair at the terminus of the reacting duplex, and the intact secondary structure of the enzyme helical cap. Optimal positioning of the scissile phosphate additionally required active site conserved residues Tyr(40), Asp(181), and Arg(100)and a reacting duplex 5'-phosphate. These studies suggest a FEN1 reaction mechanism where junctions are bound and 5'-flaps are threaded (when present), and finally the substrate is transferred onto active site metals initiating cleavage.

  16. DNA and Protein Requirements for Substrate Conformational Changes Necessary for Human Flap Endonuclease-1-catalyzed Reaction*

    PubMed Central

    Algasaier, Sana I.; Exell, Jack C.; Bennet, Ian A.; Thompson, Mark J.; Gotham, Victoria J. B.; Shaw, Steven J.; Craggs, Timothy D.; Finger, L. David; Grasby, Jane A.

    2016-01-01

    Human flap endonuclease-1 (hFEN1) catalyzes the essential removal of single-stranded flaps arising at DNA junctions during replication and repair processes. hFEN1 biological function must be precisely controlled, and consequently, the protein relies on a combination of protein and substrate conformational changes as a prerequisite for reaction. These include substrate bending at the duplex-duplex junction and transfer of unpaired reacting duplex end into the active site. When present, 5′-flaps are thought to thread under the helical cap, limiting reaction to flaps with free 5′-termini in vivo. Here we monitored DNA bending by FRET and DNA unpairing using 2-aminopurine exciton pair CD to determine the DNA and protein requirements for these substrate conformational changes. Binding of DNA to hFEN1 in a bent conformation occurred independently of 5′-flap accommodation and did not require active site metal ions or the presence of conserved active site residues. More stringent requirements exist for transfer of the substrate to the active site. Placement of the scissile phosphate diester in the active site required the presence of divalent metal ions, a free 5′-flap (if present), a Watson-Crick base pair at the terminus of the reacting duplex, and the intact secondary structure of the enzyme helical cap. Optimal positioning of the scissile phosphate additionally required active site conserved residues Tyr40, Asp181, and Arg100 and a reacting duplex 5′-phosphate. These studies suggest a FEN1 reaction mechanism where junctions are bound and 5′-flaps are threaded (when present), and finally the substrate is transferred onto active site metals initiating cleavage. PMID:26884332

  17. Double strand binding – single strand incision mechanism for human flap endonuclease: implications for the superfamily

    PubMed Central

    Tsutakawa, Susan E.; Tainer, John A.

    2012-01-01

    Detailed structural, mutational, and biochemical analyses of human FEN1/DNA complexes have revealed the mechanism for recognition of 5′ flaps formed during lagging strand replication and DNA repair. FEN1 processes 5′ flaps through a previously unknown, but structurally elegant double-stranded (ds) recognition/single stranded (ss) incision mechanism that both selects for 5′ flaps and selects against ss DNA or RNA, intact dsDNA, and 3′ flaps. Two major DNA binding interfaces, including a K+ bridge between the DNA and the H2TH motif, are spaced one helical turn apart and together select for substrates with dsDNA. A conserved helical gateway and a helical cap protects the two-metal active site and selects for ss flaps with free termini. Structures of substrate and product reveal an unusual step between binding substrate and incision that involves a double base unpairing with incision occurring in the resulting unpaired DNA or RNA. Ordering of the active site requires a disorder-to-order transition induced by binding of an unpaired 3′ flap, which ensures that the product is ligatable. Comparison with FEN superfamily members, including XPG, EXO1, and GEN1, identifies superfamily motifs such as the helical gateway that select for ss-dsDNA junctions and provides key biological insights into nuclease specificity and regulation. PMID:22244820

  18. Hydrostatic Pressure Studies Distinguish Global from Local Protein Motions in C-H Activation by Soybean Lipoxygenase-1.

    PubMed

    Hu, Shenshen; Cattin-Ortolá, Jérôme; Munos, Jeffrey W; Klinman, Judith P

    2016-08-01

    The proposed contributions of distinct classes of local versus global protein motions during enzymatic bond making/breaking processes has been difficult to verify. We employed soybean lipoxygenase-1 as a model system to investigate the impact of high pressure at variable temperatures on the hydrogen-tunneling properties of the wild-type protein and three single-site mutants. For all variants, pressure dramatically elevates the enthalpies of activation for the C-H activation. In contrast, the primary kinetic isotope effects (KIEs) for C-H activation and their corresponding temperature dependencies remain unchanged up to ca. 700 bar. The differential impact of elevated hydrostatic pressure on the temperature dependencies of rate constants versus substrate KIEs provides direct evidence for two distinct classes of protein motions: local, isotope-dependent donor-acceptor distance-sampling modes, and a more global, isotope-independent search for productive protein conformational sub-states. PMID:27348724

  19. Local Injection of Deferoxamine Improves Neovascularization in Ischemic Diabetic Random Flap by Increasing HIF-1α and VEGF Expression

    PubMed Central

    Zhang, Yun; Xiong, Zhuyou; Li, Guangzao; Cui, Lei

    2014-01-01

    Background Although the systemic administration of deferoxamine (DFO) is protective in experimental models of normal ischemic flap and diabetic wound, its effect on diabetic flap ischemia using a local injection remains unknown. Objective To explore the feasibility of local injection of DFO to improve the survival of ischemic random skin flaps in streptozotocin (STZ)-induced diabetic mice. Methods Ischemic random skin flaps were made in 125 mice. Animals were divided into the DFO-treated (n = 20), PBS-treated (n = 16) and untreated (n = 16) groups. Surviving area, vessel density, and expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) were evaluated on the seventh day after local injection. Results The viability of DFO-treated flap was significantly enhanced, with increased regional blood perfusion and capillary density compared with those in the two control groups. Fluorescence-activated cell sorting (FACS) analysis demonstrated a marked increase in systemic Flk-1+/CD11b− endothelial progenitor cells (EPCs) in DFO-treated mice. Furthermore, the expression of VEGF and HIF-1α was increased not only in diabetic flap tissue, but also in dermal fibroblasts cultured under hyperglycemic and hypoxic conditions. Conclusions Local injection of DFO could exert preventive effects against skin flap necrosis in STZ-induced diabetic mice by elevating the expression of HIF-1α and VEGF, increased EPC mobilization, which all contributed to promote ischemic diabetic flap survival. PMID:24963878

  20. A review of progress and challenges in flapping foil power generation

    NASA Astrophysics Data System (ADS)

    Young, John; Lai, Joseph C. S.; Platzer, Max F.

    2014-05-01

    Power may be extracted from a flowing fluid in a variety of ways. Turbines using one or more oscillating foils are under increasingly active investigation, as an alternative to rotary wind turbines and river, oceanic and tidal current water turbines, although industrial development is at a very nascent stage. Such flapping foil turbines promise some key potential advantages, including lower foil velocities (and hence lower noise and wildlife impact), and more effective small-scale and shallow water operation. The role of a number of parameters is investigated, including foil kinematics (modes, frequencies, amplitudes and time histories of motion), foil and system geometry (shape, configuration and structural flexibility), and flow physics effects (Reynolds number and turbulence, shear flows and ground effect). Details of the kinematics are shown to have the single largest influence on power output and efficiency (measured as the ratio of power output to that available and accessible in the fluid stream). The highest levels of power and efficiency are associated with very large foil pitch angles (upwards of 70°) and angles of attack (30-40°), such that the flow is massively separated for much of the flapping cycle, in contrast to rotary turbines which rely on attached flow over as much of the rotor disk as possible. This leads to leading edge vortices comparable in size to the foil chord, and the evolution and interaction of these vortices with the foil as it moves play a central role in determining performance. The other parameters also influence the vortex behaviour, but in general to a lesser degree. Numerous gaps in the research literature and outstanding issues are highlighted.

  1. Lift and thrust generation by a butterfly-like 3D flapping wing model

    NASA Astrophysics Data System (ADS)

    Suzuki, Kosuke; Inamuro, Takaji

    2013-11-01

    The flapping flight of tiny insects such as a butterfly is of fundamental interest not only in biology itself but also in its practical use for the development of micro air vehicles. It is known that a butterfly flaps downward for generating lift force and backward for generating thrust force. In this study, we consider a simple butterfly-like 3D flapping wing model whose body is a thin rod, wings are rigid and rectangular, and wing motion is simplified. We investigate the lift and thrust generation by the butterfly-like flapping wing model by using the immersed boundary-lattice Boltzmann method. Firstly, we compute the lift and thrust forces when the body of the model is fixed for Reynolds numbers in the range of 50 - 1000. In addition, we evaluate the supportable mass for each Reynolds number by using the computed lift force. Secondly, we simulate the free flight where the body can move translationally but cannot rotate. As results, we find that the evaluated supportable mass can be supported even in the free flight, and the wing model with the mass and the Reynolds number of a fruit fly can go upward against the gravity. Finally, we simulate the effect of the rotation of the body. As results, we find that the body has a large pitching motion and consequently gets off-balance.

  2. Active control of the attitude motion and structural vibration of a flexible satellite by jet thrusters

    NASA Astrophysics Data System (ADS)

    Lee, Mokin

    A Lagrangian formulation is used to obtain the equations of motion of a flexible satellite in a tree-type geometry. The flexible satellite model is the geosynchronous INSAT-II type satellite with a flexible balance beam and a flexible solar panel attached to the rigid main body. In deriving the equations of motion, the orbital motion, the librational motion, and the structural motion of flexible bodies are involved. The assumed-modes method is used to express the deflections of the flexible structures in the form of a finite series of space-dependent admissible functions multiplied by time-dependent amplitudes. The kinetic energy, potential energy, strain energy, and virtual work of the flexible satellite are evaluated as functions of time in terms of the generalized coordinates. Then, by substituting them into Lagrange's equations for discrete systems, the governing equations of motion of the flexible satellite are obtained as a set of second-order nonlinear ordinary differential equations. The attitude motion and the structural motion of the flexible satellite are coupled motions with one another. Uncontrolled dynamics show that the librational and structural motions are oscillatory and undamped motions. The stability and performance of the flexible satellite needs to be improved by designing control systems. A control objective is proposed to improve the stability and performance for pointing accuracy maneuver by controlling the librational motions and flexible modes simultaneously. For the control objective, a control system is synthesized, using feedback linearization control, thrust determination, thrust management, and pulse-width pulse-frequency modulation. Feedback linearization for second-order nonlinear systems is used to obtain a stable feedback control system for the pointing-accuracy control. A stable feedback control system is obtained by adjusting the diagonal matrices of the linear second-order system. Jet thrusters are used as the primary

  3. Using Motion-Sensor Games to Encourage Physical Activity for Adults with Intellectual Disability.

    PubMed

    Taylor, Michael J; Taylor, David; Gamboa, Patricia; Vlaev, Ivo; Darzi, Ara

    2016-01-01

    Adults with Intellectual Disability (ID) are at high risk of being in poor health as a result of exercising infrequently; recent evidence indicates this is often due to there being a lack of opportunities to exercise. This pilot study involved an investigation of the use of motion-sensor game technology to enable and encourage exercise for this population. Five adults (two female; 3 male, aged 34-74 [M = 55.20, SD = 16.71] with ID used motion-sensor games to conduct exercise at weekly sessions at a day-centre. Session attendees reported to have enjoyed using the games, and that they would like to use the games in future. Interviews were conducted with six (four female; two male, aged 27-51 [M = 40.20, SD = 11.28]) day-centre staff, which indicated ways in which the motion-sensor games could be improved for use by adults with ID, and barriers to consider in relation to their possible future implementation. Findings indicate motion-sensor games provide a useful, enjoyable and accessible way for adults with ID to exercise. Future research could investigate implementation of motion-sensor games as a method for exercise promotion for this population on a larger scale.

  4. Tongue reconstruction with minimal donor site morbidity using a deep inferior epigastric perforator (DIEP) free flap in a 6-year-old girl.

    PubMed

    Yano, Tomoyuki; Okazaki, Mutsumi; Kawaguchi, Runa; Suesada, Nobuko; Tanaka, Kentaro; Kishimoto, Seiji

    2013-09-01

    Tongue reconstruction was performed using a deep inferior epigastric perforator (DIEP) free flap in a 6-year-old girl with undifferentiated sarcoma of the tongue. After hemi-glossectomy with upper neck dissection, a 3-lobed DIEP free flap was used for the reconstruction. Donor site was closed primarily with suturing umbilicus in proper position. No flap loss, leakage, or infection occurred. Postoperatively, the patient was able to consume a normal diet without difficulty or aspiration and displayed good speech function. No donor site morbidity, e.g., herniation or bulging, was observed, and the patient was able to perform their normal daily activities. DIEP flaps provide a pliable skin paddle, an adequate amount of adipose tissue, and reduced donor site morbidity, even in children. We did not have any difficulty harvesting the DIEP flap or with the microvascular anastomosis. We consider DIEP free flaps to be the ideal option for pediatric tongue reconstruction.

  5. Mechanically Activated Motion of a Single Self-Propelled Polymeric Microcapsule

    NASA Astrophysics Data System (ADS)

    Kolmakov, German; Schaefer, Alexander; Aranson, Igor; Balazs, Anna

    2011-03-01

    Using a hybrid computational approach, we demonstrate that a single nanoparticle-filled microcapsule on a rigid substrate can undergo self-sustained motion in response to initial mechanical deformation. Nanoparticles released from the capsule modify the underlying substrate and the adhesion gradients of the nanoparticle concentration formed at the surface sustain the motion of the capsule. The permeability of the microcapsule's shell increases with its deformation and therefore, more deformed microcapsules release nanoparticles at higher rates. An initial, non-uniform mechanical deformation of the capsule by an applied force causes an asymmetry in the nanoparticle distribution on the substrate that initiates the microcapsule motion. We also develop a two-dimensional model of the phenomenon within the phase-field approximation and compare the results of the two approaches.

  6. Comparison of the effects of troxerutin and heparinoid on flap necrosis.

    PubMed

    Celik, Alper; Ersoy, Omer F; Ozkan, Namik; Kayaoglu, Huseyin A; Ozugurlu, Fikret; Cakir, Ebru A; Lordlar, Nese; Omeroglu, Suna

    2010-05-01

    We aimed to assess the effects of local troxerutin and heparinoid (HEP) treatments in a model of flap necrosis. Three groups of Wistar albino rats, each comprising 10 animals were used. A cranially based 6x3-cm full-thickness random-pattern skin flap was raised and sutured to the same area in each model. The control group was treated daily with normal saline, the second with topical HEP and the third with topical troxerutin. The amount of flap necrosis was measured in all groups by the end of the seventh day. Flap tissues were excised for histological analysis and evaluation of the expression of vascular endothelial growth factor (VEGF) levels. Assessment of the blood levels of nitric oxide was also performed in each animal by cardiac puncture. The mean area of flap necrosis was 110.6mm(2) in the control, 39.44 mm(2) in the troxerutin and 47.11 mm(2) in the heparinoid-treated rats. The treatment arms exhibited significant reduction in areas of flap necrosis, compared with the control group (p<0.001), but it was similar among treatment groups (p=0.60). The rates of fibroblast proliferation were decreased in control group as compared to HEP and troxerutin arms (p<0.001). The mean level of collagen density, collagen organisation, granulation tissue and demarcation were similar in all rats. Measurement of VEGF expression did not show any significant difference between the groups (p=0.30). Nitric oxide levels were significantly higher in control rats, as compared to treatment groups (p<0.0001), but were similar in treatment arms (p=0.45). Our results suggest that troxerutin and HEP effectively reduce the flap necrosis and improve flap survival. The observed effects might be due to their anti-oedematogenic, radical-scavenging, antioxidant effects and supportive activities on capillary permeability and transudation.

  7. Aerodynamic characteristics of a wing with Fowler flaps including flap loads, downwash, and calculated effect on take-off

    NASA Technical Reports Server (NTRS)

    Platt, Robert C

    1936-01-01

    This report presents the results of wind tunnel tests of a wing in combination with each of three sizes of Fowler flap. The purpose of the investigation was to determine the aerodynamic characteristics as affected by flap chord and position, the air loads on the flaps, and the effect of flaps on the downwash.

  8. TRAM flap breast reconstruction after radiation treatment.

    PubMed Central

    Williams, J K; Bostwick, J; Bried, J T; Mackay, G; Landry, J; Benton, J

    1995-01-01

    OBJECTIVE: Patients with and without radiation treatment before their breast reconstruction were compared to study the relationship of radiation to flap-related complications. SUMMARY BACKGROUND DATA: The transverse rectus abdominis muscle (TRAM) flap for breast reconstruction involves a a vascular pedicle and recipient bed, both included in the radiated field of patients undergoing adjunctive therapy. Detailed reviews of flap-related complications in this subgroup of patients have been limited. METHODS: One hundred eight patients with radiation treatment who subsequently underwent a TRAM flap breast reconstruction were compared with 572 patients with no radiation treatment before similar reconstruction. Flap-related complications, radiation dosage, time, fields, relationships between risk factors, and complications were studied. RESULTS: Overall complication rates were comparable between the two groups. Only fat necrosis (> 10% of total reconstruction) was found to be statistically significant (17.6% vs. 10.1%, p = 0.03228). No difference was found for fat necrosis in unipedicled vs. bipedicled flaps controlled for radiation (17.7% vs. 17.4%). Obesity and radiation therapy were associated with fat necrosis and major infection in a logistic regression. Significant abdominal scarring was also associated with major infection (p = 0.0044). CONCLUSIONS: In this, the largest reported series, radiation therapy was associated with increased fat necrosis and major infection. The use of the TRAM flap was not found to be prohibitive in radiated patients and should still be the first choice in this subgroup of patients. Images Figure 1. Figure 2. PMID:7794079

  9. Preputial flaps to correct buried penis.

    PubMed

    Chu, Chih-Chun; Chen, Yi-Hsin; Diau, Guan-Yeu; Loh, Ih-Wei; Chen, Ke-Chi

    2007-11-01

    The authors developed a preputial skin flap technique to correct the buried penis which was simple and practical. This simple procedure can be applied to most boys with buried penis. In the last 3 years, we have seen 12 boys with buried penis and have been treated by using preputial flaps. The mean age is about 5.1 (from 3 to 12). By making a longitudinal incision on the ventral side of penis, the tightness of the foreskin is released and leave a diamond-shaped skin defect. It allows the penile shaft to extend out. A circumferential incision is made about 5 mm proximal to the coronal sulcus. Pedicled preputial flaps are obtained leaving optimal penile skin on the dorsal side. The preputial skin flaps are rotated onto the ventral side and tailored to cover the defect. All patients are followed for at least 3 months. Edema and swelling on the flaps are common, but improves with time. None of our patients need a second operation. The preputial flaps technique is a simple technique which allows surgeons to deal with most cases of buried penis by tailoring the flaps providing good cosmetic and functional results.

  10. Critical Mach Numbers of Thin Airfoil Sections with Plain Flaps

    NASA Technical Reports Server (NTRS)

    Pardee, Otway O'm.; Heaslet, Max A.

    1946-01-01

    Critical Mach number as function of lift coefficient is determined for certain moderately thick NACA low-drag airfoils. Results, given graphically, included calculations on same airfoil sections with plain flaps for small flap deflections. Curves indicate optimum critical conditions for airfoils with flaps in such form that they can be compared with corresponding results for zero flap deflections. Plain flaps increase life-coefficient range for which critical Mach number is in region of high values characteristic of low-drag airfoils.

  11. Magnetostrictively actuated control flaps for vibration reduction in helicopter rotors

    SciTech Connect

    Millott, T.; Friedmann, P.P.

    1994-12-31

    High vibration levels can impose constraints on helicopter operations and hinder passenger acceptance. Vibration reduction using blade root pitch control introduces a significant power penalty and may adversely affect the airworthiness of the flight control system. Comparable levels of vibration reduction can be achieved using considerably less power through an actively controlled trailing edge flap mounted on the blade. Such a device would have no effect on helicopter airworthiness since it is controlled by a loop separate from the primary flight control system which utilizes the swashplate. Control flap actuation using the magnetostrictive material Terfenol-D is studied in this paper by designing a minimum weight actuator, subject to a set of actuation and stress constraints. The resulting device is capable of producing vibration reduction in excess of 90% at cruise conditions.

  12. Extension of the stability of motions in a combustion chamber by non- linear active control based on hysteresis

    SciTech Connect

    Knoop, P.; Culick, F.E.C.; Zukoski, E.E.

    1996-07-01

    This report presents the first quantitative data establishing the details of hysteresis whose existence in dynamical behavior was reported by Sterling and Zukoski. The new idea was demonstrated that the presence of dynamical hysteresis provides opportunity for a novel strategy of active nonlinear control of unsteady motions in combustors. A figure shows the hysteresis exhibited for the amplitude of pressure oscillations as a function of equivalence ratio in a combustor having a recirculation zone, in this case a dump combustor.

  13. Pedicled Supraclavicular Artery Island Flap Versus Free Radial Forearm Flap for Tongue Reconstruction Following Hemiglossectomy.

    PubMed

    Zhang, Senlin; Chen, Wei; Cao, Gang; Dong, Zhen

    2015-09-01

    This study investigated the tongue function and donor-site morbidity of patients with malignant tumors who had undergone immediate flap reconstruction surgery. Twenty-seven patients who had undergone immediate reconstruction after hemiglossectomy were observed. Twelve patients were reconstructed using the pedicled supraclavicular artery island flap (PSAIF) and 15 patients using the free radial forearm flap (FRFF). Flap survival, speech and swallowing function, and donor-site morbidity at the 6-month follow-up were evaluated. All the flaps were successfully transferred. No obvious complications were found in either the transferred flaps or donor regions. Age, sex, defect extent, speech and swallowing function were comparable between the 2 groups. Donor-site complications were less frequent with PSAIF reconstruction than FRFF reconstruction. The PSAIF is reliable and well suited for hemiglossectomy defect. It has few significant complications, and allows preservation of oral function.

  14. On the generation of side-edge flap noise. [part span trailing edge flaps

    NASA Technical Reports Server (NTRS)

    Howe, M. S.

    1981-01-01

    A theory is proposed for estimating the noise generated at the side edges of part span trailing edge flaps in terms of pressure fluctuations measured just in-board of the side edge of the upper surface of the flap. Asymptotic formulae are developed in the opposite extremes of Lorentz contracted acoustic wavelength large/small compared with the chord of the flap. Interpolation between these limiting results enables the field shape and its dependence on subsonic forward flight speed to be predicted over the whole frequency range. It is shown that the mean width of the side edge gap between the flap and the undeflected portion of the airfoil has a significant influence on the intensity of the radiated sound. It is estimated that the noise generated at a single side edge of a full scale part span flap can exceed that produced along the whole of the trailing edge of the flap by 3 dB or more.

  15. A review of propeller flaps for distal lower extremity soft tissue reconstruction: Is flap loss too high?

    PubMed

    Nelson, Jonas A; Fischer, John P; Brazio, Philip S; Kovach, Stephen J; Rosson, Gedge D; Rad, Ariel N

    2013-10-01

    Soft tissue coverage in the distal lower extremity remains a significant challenge. While free flaps are often utilized for larger defects, local perforator-based propeller flaps may be ideal for smaller wounds requiring coverage. Propeller flaps can provide excellent form and function for both traumatic and atraumatic defects with minimal donor site morbidity but can have concerning rates of flap loss. We reviewed the literature, identifying 21 studies presenting 310 propeller flaps for distal lower extremity reconstruction. Total flap necrosis was noted in 5.5% of flaps, with partial necrosis in 11.6%. While these flaps do enable transfer of local, healthy tissue to the defect site without the need for a microsurgical anastomosis, this rate of flap loss is concerning and appropriate patient selection is crucial. This review provides a brief history and overview of the clinical application and research into distal lower extremity perforator propeller flaps to place this technique into a clinical context.

  16. Contrast Affects fMRI Activity in Middle Temporal Cortex Related to Center–Surround Interaction in Motion Perception

    PubMed Central

    Turkozer, Halide B.; Pamir, Zahide; Boyaci, Huseyin

    2016-01-01

    As the size of a high contrast drifting Gabor patch increases, perceiving its direction of motion becomes harder. However, the same behavioral effect is not observed for a low contrast Gabor patch. Neuronal mechanisms underlying this size–contrast interaction are not well understood. Here using psychophysical methods and functional magnetic resonance imaging (fMRI), we investigated the neural correlates of this behavioral effect. In the behavioral experiments, motion direction discrimination thresholds were assessed for drifting Gabor patches with different sizes and contrasts. Thresholds increased significantly as the size of the stimulus increased for high contrast (65%) but did not change for low contrast (2%) stimuli. In the fMRI experiment, cortical activity was recorded while observers viewed drifting Gabor patches with different contrasts and sizes. We found that the activity in middle temporal (MT) area increased with size at low contrast, but did not change at high contrast. Taken together, our results show that MT activity reflects the size–contrast interaction in motion perception. PMID:27065922

  17. Experimental and numerical characterization of the structural dynamics of flapping beams

    NASA Astrophysics Data System (ADS)

    Ozcelik, Orhan; Attar, Peter J.; Altan, M. Cengiz; Johnston, Jordan W.

    2013-10-01

    The nonlinear structural dynamics of a slender beam in flapping motion is examined both experimentally and computationally. In the experiments the periodic flapping motion is imposed on the clamped edge of the cantilever beam using a 4-bar crank-and-rocker mechanism. Aluminum beams with nominal dimensions of 150 mm×25 mm×0.4 mm are tested in air over a range of flapping frequencies up to 1.3 times the linear first modal frequency at two different flapping amplitudes, 15° and 30°. The response of the beam is characterized experimentally through bending strain and tip displacement data obtained from foil strain gage and high-speed camera, respectively. It was determined that for the particular combination of beam specimen (dimensions, material properties) and forcing parameters investigated, all experimental responses were periodic. The frequency response curves based upon the experimental bending strain data reveal a secondary superharmonic peak in addition to the primary resonance peak. As the flapping frequency is increased, the response of the beam is observed to change from symmetric (with respect to equilibrium position) periodic vibrations with a period equal to the flapping period to asymmetric periodic vibrations with higher harmonic content featuring local oscillations in the time histories. Experimental tip displacement results show that the beam spends more time during stroke reversals when the flapping frequency is near primary and secondary resonance regions. In addition to experiment, numerical simulations are performed using two-node, isoparametric degenerate-continuum based geometrically nonlinear beam elements. The HHT-α version of the Newmark finite difference scheme is used to discretize the problem in time and a linear viscous damping model is assumed. Overall the numerical simulations agree well with the experiments and capture most of the nonlinear dynamical features of the beam response. It is, however, found that in resonance regions the

  18. Flap-augmented shrouds for aerogenerators

    NASA Technical Reports Server (NTRS)

    Seginer, A.

    1976-01-01

    Axisymmetrical shrouds for windmills are augmented by ring-shaped 'flaps' and their performance is studied experimentally. The concept of the shroud as an annular 'wing' is justified, leading to the conclusion that high-lift techniques should be used in shroud design, and that high-lift devices, such as flaps, would increase the power output of the windmill. It is shown experimentally that the ideal power output of a flap-augmented shrouded turbine can be more than 4 times the power of unshrouded turbines of the same diameter.

  19. Dynamic response of a piezoelectric flapping wing

    NASA Astrophysics Data System (ADS)

    Kumar, Alok; Khandwekar, Gaurang; Venkatesh, S.; Mahapatra, D. R.; Dutta, S.

    2015-03-01

    Piezo-composite membranes have advantages over motorized flapping where frequencies are high and certain coupling between bending and twisting is useful to generate lift and forward flight. We draw examples of fruit fly and bumble bee. Wings with Piezo ceramic PZT coating are realized. The passive mechanical response of the wing is characterized experimentally and validated using finite element simulation. Piezoelectric actuation with uniform electrode coating is characterized and optimal frequencies for flapping are identified. The experimental data are used in an empirical model and advanced ratio for a flapping insect like condition for various angular orientations is estimated.

  20. Physics of active jamming during collective cellular motion in a monolayer.

    PubMed

    Garcia, Simon; Hannezo, Edouard; Elgeti, Jens; Joanny, Jean-François; Silberzan, Pascal; Gov, Nir S

    2015-12-15

    Although collective cell motion plays an important role, for example during wound healing, embryogenesis, or cancer progression, the fundamental rules governing this motion are still not well understood, in particular at high cell density. We study here the motion of human bronchial epithelial cells within a monolayer, over long times. We observe that, as the monolayer ages, the cells slow down monotonously, while the velocity correlation length first increases as the cells slow down but eventually decreases at the slowest motions. By comparing experiments, analytic model, and detailed particle-based simulations, we shed light on this biological amorphous solidification process, demonstrating that the observed dynamics can be explained as a consequence of the combined maturation and strengthening of cell-cell and cell-substrate adhesions. Surprisingly, the increase of cell surface density due to proliferation is only secondary in this process. This analysis is confirmed with two other cell types. The very general relations between the mean cell velocity and velocity correlation lengths, which apply for aggregates of self-propelled particles, as well as motile cells, can possibly be used to discriminate between various parameter changes in vivo, from noninvasive microscopy data.

  1. Physics of active jamming during collective cellular motion in a monolayer

    PubMed Central

    Garcia, Simon; Hannezo, Edouard; Elgeti, Jens; Joanny, Jean-François; Silberzan, Pascal; Gov, Nir S.

    2015-01-01

    Although collective cell motion plays an important role, for example during wound healing, embryogenesis, or cancer progression, the fundamental rules governing this motion are still not well understood, in particular at high cell density. We study here the motion of human bronchial epithelial cells within a monolayer, over long times. We observe that, as the monolayer ages, the cells slow down monotonously, while the velocity correlation length first increases as the cells slow down but eventually decreases at the slowest motions. By comparing experiments, analytic model, and detailed particle-based simulations, we shed light on this biological amorphous solidification process, demonstrating that the observed dynamics can be explained as a consequence of the combined maturation and strengthening of cell−cell and cell−substrate adhesions. Surprisingly, the increase of cell surface density due to proliferation is only secondary in this process. This analysis is confirmed with two other cell types. The very general relations between the mean cell velocity and velocity correlation lengths, which apply for aggregates of self-propelled particles, as well as motile cells, can possibly be used to discriminate between various parameter changes in vivo, from noninvasive microscopy data. PMID:26627719

  2. Application of a novel spinal posture and motion measurement system in active and static sitting.

    PubMed

    Pries, Esther; Dreischarf, Marcel; Bashkuev, Maxim; Schmidt, Hendrik

    2015-01-01

    The quantification of work-related musculoskeletal risk factors is of great importance; however, only a few tools allow objective, unrestricted measurements of spinal posture and motion in workplaces. This study was performed to evaluate the applicability of the Epionics system in a sedentary workplace. The system is mobile and wireless and assesses lumbar lordosis, pelvic orientation and spinal motion, without restricting subjects in their movements. In total, 10 males were monitored while sitting for 2 h on static and dynamic office chairs and on an exercise ball, to evaluate the effect of dynamic sitting. The volunteers were able to perform their work unhampered. No differences among the tested furniture could be detected with respect to either the lordosis or the number of spinal movements after habituation to the furniture; however, differences in pelvic orientation were statistically significant. The results of the present study indicate that Epionics may be useful for the quantitative assessment of work-related risk factors. Practitioner Summary: Only a few tools allow objective, unrestricted measurements of spinal posture and motion in the workplace. Epionics SPINE measures lumbar lordosis, pelvic orientation and spinal motion under nearly unrestricted conditions and can be used to quantify work-related musculoskeletal risk factors. We demonstrated the use of this tool in the workplace-analysis. PMID:25712870

  3. Physics of active jamming during collective cellular motion in a monolayer.

    PubMed

    Garcia, Simon; Hannezo, Edouard; Elgeti, Jens; Joanny, Jean-François; Silberzan, Pascal; Gov, Nir S

    2015-12-15

    Although collective cell motion plays an important role, for example during wound healing, embryogenesis, or cancer progression, the fundamental rules governing this motion are still not well understood, in particular at high cell density. We study here the motion of human bronchial epithelial cells within a monolayer, over long times. We observe that, as the monolayer ages, the cells slow down monotonously, while the velocity correlation length first increases as the cells slow down but eventually decreases at the slowest motions. By comparing experiments, analytic model, and detailed particle-based simulations, we shed light on this biological amorphous solidification process, demonstrating that the observed dynamics can be explained as a consequence of the combined maturation and strengthening of cell-cell and cell-substrate adhesions. Surprisingly, the increase of cell surface density due to proliferation is only secondary in this process. This analysis is confirmed with two other cell types. The very general relations between the mean cell velocity and velocity correlation lengths, which apply for aggregates of self-propelled particles, as well as motile cells, can possibly be used to discriminate between various parameter changes in vivo, from noninvasive microscopy data. PMID:26627719

  4. Validating the method of pressure sensing to optimize flapping foil energy extraction

    NASA Astrophysics Data System (ADS)

    Persichetti, Amanda J.

    Renewable energy resources are in high demand due to a world-wide desire for cleaner energy production. Flapping foil tidal driven systems have begun being tested and implemented at prototype scales. These prototype systems use limited control to maximize energy production. This thesis uses biological inspiration from the sensory system in fish to enhance the efficiency of these energy harnessing systems with the use of surface mounted pressure sensing. Eight pressure sensors were found to be a good balance for quantity with respect to cost and accuracy. Optimal locations around the foil were determined from application of a Random Search algorithm and a fluid moment approximation. A 2-D numerical code was created to simulate a NACA0015 flapping foil in uniform potential flow. A wide parameter space of sinusoidal heave and pitch motions was run and a database of force, pressure, and efficiency values along with flow visualization was built. An efficiency of 0.43 was reached for the trajectory of motion with a pitch amplitude of 90 degrees, heave amplitude of 1.25 and a Strouhal number of 0.5. A control platform dependent on pressure measurements at the eight sensor locations was created in the 2-D numerical code. By implementing basic control, motion trajectories converge to the optimal motion based on pressure comparisons around the foil to pressure traces from the motion with highest efficiency. In addition, a laboratory for experimental testing and validation was set-up. The motion control system was connected and tested for a tow tank set-up. Motion programs were written for the same parameter space modeled in this thesis. Through numerical modeling, pressure sensing was found to be an effective method to enhancing the efficiency of a flapping foil energy extraction system.

  5. Propeller Flap Reconstruction in Post Oncological Thigh Defect: "The Move in Flap".

    PubMed

    Nambi, G I; Salunke, Abhijeet Ashok

    2015-06-01

    Reconstruction of soft tissue defects of the limb after tumor resection is challenging question for oncosurgeons. The management differs from reconstruction of post traumatic defects due to the complexity of the primary surgery and subsequent radiation. The conventional propeller flap is based on a perforator which is located close to the defect; but in present case the perforator was located far away from the defect. So we describe it as "Move in flap" as the flap rotated a large volume of soft tissue lying between the defect and the perforator. We present a case of post oncological thigh defect with reconstruction using a propeller flap based on distal anteromedial perforator.

  6. Motion sickness in migraine sufferers.

    PubMed

    Marcus, Dawn A; Furman, Joseph M; Balaban, Carey D

    2005-12-01

    Motion sickness commonly occurs after exposure to actual motion, such as car or amusement park rides, or virtual motion, such as panoramic movies. Motion sickness symptoms may be disabling, significantly limiting business, travel and leisure activities. Motion sickness occurs in approximately 50% of migraine sufferers. Understanding motion sickness in migraine patients may improve understanding of the physiology of both conditions. Recent literature suggests important relationships between the trigeminal system and vestibular nuclei that may have implications for both motion sickness and migraine. Studies demonstrating an important relationship between serotonin receptors and motion sickness susceptibility in both rodents and humans suggest possible new motion sickness prevention therapies.

  7. Neural correlates of apparent motion perception of impoverished facial stimuli: A comparison of ERP and ERSP activity

    PubMed Central

    Kolchinsky, Artemy; Puce, Aina

    2014-01-01

    Our brains readily decode human movements, as shown by neural responses to face and body motion. N170 event-related potentials (ERPs) are earlier and larger to mouth opening movements relative to closing in both line-drawn and natural faces, and gaze aversions relative to direct gaze in natural faces (Puce and Perrett, 2003; Puce et al., 2000). Here we extended this work by recording both ERP and oscillatory EEG activity (event-related spectral perturbations, ERSPs) to line-drawn faces depicting eye and mouth movements (Eyes: Direct vs Away; Mouth: Closed vs Open) and non-face motion controls. Neural activity was measured in 2 occipitotemporal clusters of 9 electrodes, one in each hemisphere. Mouth opening generated larger N170s than mouth closing, replicating earlier work. Eye motion elicited robust N170s that did not differ between gaze conditions. Control condition differences were seen, and generated the largest N170. ERSP difference plots across conditions in the occipitotemporal electrode clusters (Eyes: Direct vs Away; Mouth: Closed vs Open) showed statistically significant differences in beta and gamma bands for gaze direction changes and mouth opening at similar post-stimulus times and frequencies. In contrast, control stimuli showed activity in the gamma band with a completely different time profile and hemispheric distribution to facial stimuli. ERSP plots were generated in two 9 electrode clusters centered on central sites, C3 and C4. In the left cluster for all stimulus conditions, broadband beta suppression persisted from about 250 ms post-motion onset. In the right cluster, beta suppression was seen for control conditions only. Statistically significant differences between conditions were confined between 4 – 15 Hz, unlike occipitotemporal sites where differences occurred at much higher frequencies (high beta/gamma). Our data indicate that N170 amplitude is sensitive to the amount of movement in the visual field, independent of stimulus type. In

  8. Energy Harvesting of a Flapping Airfoil in a Vortical Wake

    NASA Astrophysics Data System (ADS)

    Zheng, Z. Charlie; Wei, Zhenglun

    2014-11-01

    We study the response of a two-dimensional flapping airfoil in the wake downstream of an oscillating D-shape cylinder. The airfoil has either heaving or pitching motions. The leading edge vortex (LEV) and trailing edge vortex (TEV) of the airfoil play important roles in energy harvesting. Two major interaction modes between the airfoil and incoming vortices, the suppressing mode and the reinforcing mode, are identified. However, distinctions exist between the heaving and pitching motion in terms of their contributions to the interaction modes and the efficiency of the energy extraction. A potential theory and the related fluid dynamics analysis are developed to analytically demonstrate that the topology of the incoming vortices corresponding to the airfoil is the primary factor that determines the interaction modes. Finally, the trade-off between the input and the output is discussed. It is found that appropriate operational parameters for the heaving motion are preferable in order to preserve acceptable input power for energy harvesters, while appropriate parameters for the pitching motion are essential to achieve decent output power.

  9. Effects of diammonium glycyrrhizinate on random skin flap survival in rats: An experimental study

    PubMed Central

    Lv, Qing-Bo; Gao, Xiang; Lin, Ding-Sheng; Chen, Yun; Cao, Bin; Zhou, Kai-Liang

    2016-01-01

    Partial necrosis of skin flaps continues to restrict the survival of local skin flaps following plastic and reconstructive surgeries. The aim of the present study was to investigate the effects of diammonium glycyrrhizinate (DG), a salt of glycyrrhetinic acid that has been widely used in the therapy of chronic hepatitis and human immunodeficiency virus infection, on random skin flap survival in rats. McFarlane flaps were established in 60 male Sprague-Dawley rats randomly divided into three groups. Group I served as the control group and was injected with saline (10 mg/kg) once per day. Group II and group III were the experimental groups, and were injected with 10 mg/kg DG once and twice per day, respectively. On day 7, the survival area of the flap was measured. Tissue samples were stained with hematoxylin and eosin and immunohistochemically evaluated. Tissue edema, neutrophil density, superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were evaluated. The mean survival areas of the flaps of group II were significantly larger when compared with those of group I (P<0.05), and the rats of group III exhibited significantly higher survival areas than group II (P<0.05). Histologic and immunohistochemical evaluation showed that microvessel development and the expression level of vascular endothelial growth factor were higher in the two experimental groups than in the control group. Furthermore, SOD activity was significantly increased (P<0.05), while the neutrophil density and MDA level were significantly reduced (P<0.05) in group II when compared with group I. Significant differences between group II and group III with regard to SOD activity and MDA level were also observed (P<0.05). Thus, DG may have a dose-dependent effect on promoting the survival of random skin flaps. PMID:27588181

  10. Route Flap Damping Made Usable

    NASA Astrophysics Data System (ADS)

    Pelsser, Cristel; Maennel, Olaf; Mohapatra, Pradosh; Bush, Randy; Patel, Keyur

    The Border Gateway Protocol (BGP), the de facto inter-domain routing protocol of the Internet, is known to be noisy. The protocol has two main mechanisms to ameliorate this, MinRouteAdvertisementInterval (MRAI), and Route Flap Damping (RFD). MRAI deals with very short bursts on the order of a few to 30 seconds. RFD deals with longer bursts, minutes to hours. Unfortunately, RFD was found to severely penalize sites for being well-connected because topological richness amplifies the number of update messages exchanged. So most operators have disabled it. Through measurement, this paper explores the avenue of absolutely minimal change to code, and shows that a few RFD algorithmic constants and limits can be trivially modified, with the result being damping a non-trivial amount of long term churn without penalizing well-behaved prefixes' normal convergence process.

  11. Clinimetric evaluation of active range of motion measures in patients with non-specific neck pain: a systematic review

    PubMed Central

    van den Heuvel, Sylvia P.; Staal, J. Bart; Smits-Engelsman, Bouwien C. M.

    2008-01-01

    The study is to provide a critical analysis of the research literature on clinimetric properties of instruments that can be used in daily practice to measure active cervical range of motion (ACROM) in patients with non-specific neck pain. A computerized literature search was performed in Medline, Cinahl and Embase from 1982 to January 2007. Two reviewers independently assessed the clinimetric properties of identified instruments using a criteria list. The search identified a total of 33 studies, investigating three different types of measurement instruments to determine ACROM. These instruments were: (1) different types of goniometers/inclinometers, (2) visual estimation, and (3) tape measurements. Intra- and inter-observer reliability was demonstrated for the cervical range of motion instrument (CROM), Cybex electronic digital instrument (EDI-320) and a single inclinometer. The presence of agreement was assessed for the EDI-320 and a single inclinometer. The CROM received a positive rating for construct validity. When clinical acceptability is taken into account both the CROM and the single inclinometer can be considered appropriate instruments for measuring the active range of motion in patients with non-specific neck pain in daily practice. Reliability is the aspect most frequently evaluated. Agreement, validity and responsiveness are documented less frequently. PMID:18427843

  12. Mucocele formation under pedicled nasoseptal flap.

    PubMed

    Vaezeafshar, Reza; Hwang, Peter H; Harsh, Griffith; Turner, Justin H

    2012-01-01

    The pedicled nasoseptal flap has become an indispensible tool for the reconstruction of skull base defects. This flap is easily harvested, provides a large surface area of vascularized tissue, and has few reported complications. We describe the case of a 60-year-old man who underwent endoscopic, endonasal transsphenoidal surgery with septal flap reconstruction who developed a sphenoid sinus mucocele postoperatively. We also have reviewed the literature for similar findings and discuss this complication in the setting of pituitary surgery and endoscopic skull base repair. Although likely a rare occurrence, mucocele formation after septal flap reconstruction should be recognized and monitored with postoperative nasal endoscopy and radiologic imaging. Reoperation or mucocele drainage may be necessary if symptomatic or in cases of rapid enlargement.

  13. Postirradiation flap infection about the oral cavity

    SciTech Connect

    Cabbabe, E.B.; Herbold, D.R.; Sunwoo, Y.C.; Baroudi, I.F.

    1983-06-01

    Postirradiation alteration of oral flora is well documented in the literature. Infection as a complication leading to partial or complete loss of a flap used to reconstruct a defect in the oral cavity is a worrisome outcome. We describe how a flap that was judged clinically to be viable became overwhelmingly infected with the Klebsiella oxytoca, an oral cavity pathogen encountered in this patient following irradiation. Local and systemic changes led to detachment of the flap. This complication may be explained, in view of the absence of venous congestion or arterial ischemia both clinically and pathologically, by the proven contamination of the flap by the Klebsiella pathogen. Local factors resulted in lower resistance and subsequent overwhelming infection. Discussion of the case, review of pertinent literature, and proposed solutions are presented.

  14. A dynamical system for interacting flapping swimmers

    NASA Astrophysics Data System (ADS)

    Oza, Anand; Ramananarivo, Sophie; Ristroph, Leif; Shelley, Michael

    2015-11-01

    We present the results of a theoretical investigation into the dynamics of interacting flapping swimmers. Our study is motivated by the recent experiments of Becker et al., who studied a one-dimensional array of self-propelled flapping wings that swim within each other's wakes in a water tank. They discovered that the system adopts certain ``schooling modes'' characterized by specific spatial phase relationships between swimmers. To rationalize these phenomena, we develop a discrete dynamical system in which the swimmers are modeled as heaving airfoils that shed point vortices during each flapping cycle. We then apply our model to recent experiments in the Applied Math Lab, in which two tandem flapping airfoils are free to choose both their speed and relative positions. We expect that our model may be used to understand how schooling behavior is influenced by hydrodynamics in more general contexts. Thanks to the NSF for its support.

  15. Effect of torsional stiffness and inertia on the dynamics of low aspect ratio flapping wings.

    PubMed

    Xiao, Qing; Hu, Jianxin; Liu, Hao

    2014-03-01

    Micro air vehicle-motivated aerodynamics in biological flight has been an important subject in the past decade. Inspired by the novel flapping wing mechanisms in insects, birds and bats, we have carried out a numerical study systematically investigating a three-dimensional flapping rigid wing with passively actuated lateral and rotational motion. Distinguishing it from the limited existing studies, this work performs a systematic examination on the effects of wing aspect ratio (AR = 1.0 to infinity), inertia (density ratio σ = 4-32), torsional stiffness (frequency ratio F = 1.5-10 and infinity) and pivot point (from chord-center to leading edge) on the dynamics response of a low AR rectangular wing under an initial zero speed flow field condition. The simulation results show that the symmetry breakdown of the flapping wing results in a forward/backward motion with a rotational pitching. When the wing reaches its stable periodic state, the induced pitching frequency is identical to its forced flapping frequency. However, depending on various kinematic and dynamic system parameters, (i.e. flapping frequency, density ratio and pitching axis), the lateral induced velocity shows a number of different oscillating frequencies. Furthermore, compared with a one degree of freedom (DoF) wing in the lateral direction only, the propulsion performance of such a two DoF wing relies very much on the magnitude of torsional stiffness adding on the pivot point, as well as its pitching axis. In all cases examined here, thrust force and moment generated by a long span wing is larger than that of a short wing, which is remarkably linked to the strong reverse von Kármán vortex street formed in the wake of a wing.

  16. Optimal flapping wing for maximum vertical aerodynamic force in hover: twisted or flat?

    PubMed

    Phan, Hoang Vu; Truong, Quang Tri; Au, Thi Kim Loan; Park, Hoon Cheol

    2016-01-01

    This work presents a parametric study, using the unsteady blade element theory, to investigate the role of twist in a hovering flapping wing. For the investigation, a flapping-wing system was developed to create a wing motion of large flapping amplitude. Three-dimensional kinematics of a passively twisted wing, which is capable of creating a linearly variable geometric angle of attack (AoA) along the wingspan, was measured during the flapping motion and used for the analysis. Several negative twist or wash-out configurations with different values of twist angle, which is defined as the difference in the average geometric AoAs at the wing root and the wing tip, were obtained from the measured wing kinematics through linear interpolation and extrapolation. The aerodynamic force generation and aerodynamic power consumption of these twisted wings were obtained and compared with those of flat wings. For the same aerodynamic power consumption, the vertical aerodynamic forces produced by the negatively twisted wings are approximately 10%-20% less than those produced by the flat wings. However, these twisted wings require approximately 1%-6% more power than flat wings to produce the same vertical force. In addition, the maximum-force-producing twisted wing, which was found to be the positive twist or wash-in configuration, was used for comparison with the maximum-force-producing flat wing. The results revealed that the vertical aerodynamic force and aerodynamic power consumption of the two types of wings are almost identical for the hovering condition. The power loading of the positively twisted wing is only approximately 2% higher than that of the maximum-force-producing flat wing. Thus, the flat wing with proper wing kinematics (or wing rotation) can be regarded as a simple and efficient candidate for the development of hovering flapping-wing micro air vehicle. PMID:27387833

  17. Optimal flapping wing for maximum vertical aerodynamic force in hover: twisted or flat?

    PubMed

    Phan, Hoang Vu; Truong, Quang Tri; Au, Thi Kim Loan; Park, Hoon Cheol

    2016-07-08

    This work presents a parametric study, using the unsteady blade element theory, to investigate the role of twist in a hovering flapping wing. For the investigation, a flapping-wing system was developed to create a wing motion of large flapping amplitude. Three-dimensional kinematics of a passively twisted wing, which is capable of creating a linearly variable geometric angle of attack (AoA) along the wingspan, was measured during the flapping motion and used for the analysis. Several negative twist or wash-out configurations with different values of twist angle, which is defined as the difference in the average geometric AoAs at the wing root and the wing tip, were obtained from the measured wing kinematics through linear interpolation and extrapolation. The aerodynamic force generation and aerodynamic power consumption of these twisted wings were obtained and compared with those of flat wings. For the same aerodynamic power consumption, the vertical aerodynamic forces produced by the negatively twisted wings are approximately 10%-20% less than those produced by the flat wings. However, these twisted wings require approximately 1%-6% more power than flat wings to produce the same vertical force. In addition, the maximum-force-producing twisted wing, which was found to be the positive twist or wash-in configuration, was used for comparison with the maximum-force-producing flat wing. The results revealed that the vertical aerodynamic force and aerodynamic power consumption of the two types of wings are almost identical for the hovering condition. The power loading of the positively twisted wing is only approximately 2% higher than that of the maximum-force-producing flat wing. Thus, the flat wing with proper wing kinematics (or wing rotation) can be regarded as a simple and efficient candidate for the development of hovering flapping-wing micro air vehicle.

  18. Effect of torsional stiffness and inertia on the dynamics of low aspect ratio flapping wings.

    PubMed

    Xiao, Qing; Hu, Jianxin; Liu, Hao

    2014-03-01

    Micro air vehicle-motivated aerodynamics in biological flight has been an important subject in the past decade. Inspired by the novel flapping wing mechanisms in insects, birds and bats, we have carried out a numerical study systematically investigating a three-dimensional flapping rigid wing with passively actuated lateral and rotational motion. Distinguishing it from the limited existing studies, this work performs a systematic examination on the effects of wing aspect ratio (AR = 1.0 to infinity), inertia (density ratio σ = 4-32), torsional stiffness (frequency ratio F = 1.5-10 and infinity) and pivot point (from chord-center to leading edge) on the dynamics response of a low AR rectangular wing under an initial zero speed flow field condition. The simulation results show that the symmetry breakdown of the flapping wing results in a forward/backward motion with a rotational pitching. When the wing reaches its stable periodic state, the induced pitching frequency is identical to its forced flapping frequency. However, depending on various kinematic and dynamic system parameters, (i.e. flapping frequency, density ratio and pitching axis), the lateral induced velocity shows a number of different oscillating frequencies. Furthermore, compared with a one degree of freedom (DoF) wing in the lateral direction only, the propulsion performance of such a two DoF wing relies very much on the magnitude of torsional stiffness adding on the pivot point, as well as its pitching axis. In all cases examined here, thrust force and moment generated by a long span wing is larger than that of a short wing, which is remarkably linked to the strong reverse von Kármán vortex street formed in the wake of a wing. PMID:24434625

  19. Management of Vortices Trailing Flapped Wings via Separation Control

    NASA Technical Reports Server (NTRS)

    Greenblatt, David

    2005-01-01

    A pilot study was conducted on a flapped semi-span model to investigate the concept and viability of near-wake vortex management via separation control. Passive control was achieved by means of a simple fairing and active control was achieved via zero mass-flux blowing slots. Vortex sheet strength, estimated by integrating surface pressure ports, was used to predict vortex characteristics by means of inviscid rollup relations. Furthermore, vortices trailing the flaps were mapped using a seven-hole probe. Separation control was found to have a marked effect on vortex location, strength, tangential velocity, axial velocity and size over a wide range of angles of attack and control conditions. In general, the vortex trends were well predicted by the inviscid rollup relations. Manipulation of the separated flow near the flap edges exerted significant control over both outboard and inboard edge vortices while producing negligible lift excursions. Dynamic separation and attachment control was found to be an effective means for dynamically perturbing the vortex from arbitrarily long wavelengths down to wavelengths less than a typical wingspan. In summary, separation control has the potential for application to time-independent or time-dependent wake alleviation schemes, where the latter can be deployed to minimize adverse effects on ride-quality and dynamic structural loading.

  20. Interpreting laser Doppler recordings from free flaps.

    PubMed

    Svensson, H; Holmberg, J; Svedman, P

    1993-01-01

    Although the transfer of free flaps is nowadays accomplished with an increasing degree of safety, thrombosis of the microvascular anastomoses is still a problem. In order to avoid delay in re-operating, various methods for objective blood flow monitoring have been tried, among them Laser Doppler Flowmetry (LDF). When one reviews the literature, it is apparent that opinions differ about whether or not LDF is a reliable technique for this purpose. To focus on the need to interpret continuous recordings, this paper reports our findings in six latissimus dorsi free flaps chosen from our series of LDF monitoring procedures. One uneventful flap, no. 1, had an immediate postoperative LDF value of 4.5 perfusion units (PU). LDF values improved during the recovery period and the graphic recording showed fluctuations due to normal physiological variations of the blood flow in the flap. Another uneventful flap, no. 4, showed the same pattern, though at an appreciably lower level, 2 PU, on average. Flap no. 2 had an acceptably high value of 3.5 PU despite suffering a venous thrombosis. However, the LDF recording showed no fluctuations and the value declined gradually. Another flap, no. 3, showed fluctuations and blood flow was normal although the value decreased to 2.5 PU. In flap no. 5, any value between 2 and 3.5 PU could be obtained merely by adjusting the position of the probe in the holder. In no. 6, the LDF value suddenly dropped, accompanied by a decrease in the total amount of backscattered light, indicating venous obstruction which was confirmed at re-operation.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Extending the extended V-Y flap.

    PubMed

    Prowse, Phoebe; Morton, Jonathan

    2012-06-01

    This case report demonstrates a modification of the so-called 'Extended V-Y Flap' used to simultaneously reconstruct a defect involving the upper lip, floor of nose and alar rim following tumour excision. We hope that this case serves as a reminder of the versatility of the V-Y flap in the nasolabial region, and its considerable capacity for augmentation. PMID:22018837

  2. The origin of the temporalis muscle flap.

    PubMed

    Speculand, B

    1992-12-01

    This paper explores the origin of the temporalis muscle flap which has been attributed to Golovine, a Moscow ophthalmic surgeon, who described a forehead skin transposition flap. Small temporalis muscle transpositions were used in surgery for TMJ ankylosis, but the use of the majority of the muscle for reconstruction of facial defects was first described by Sir Harold Gillies during the 1914-18 war.

  3. Aerodynamic effects of flexibility in flapping wings.

    PubMed

    Zhao, Liang; Huang, Qingfeng; Deng, Xinyan; Sane, Sanjay P

    2010-03-01

    Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast, wings flapping at high angles of attack generate stable leading edge vorticity, which persists throughout the duration of the stroke and enhances mean aerodynamic forces. Here, we show that aerodynamic forces can be controlled by altering the trailing edge flexibility of a flapping wing. We used a dynamically scaled mechanical model of flapping flight (Re approximately 2000) to measure the aerodynamic forces on flapping wings of variable flexural stiffness (EI). For low to medium angles of attack, as flexibility of the wing increases, its ability to generate aerodynamic forces decreases monotonically but its lift-to-drag ratios remain approximately constant. The instantaneous force traces reveal no major differences in the underlying modes of force generation for flexible and rigid wings, but the magnitude of force, the angle of net force vector and centre of pressure all vary systematically with wing flexibility. Even a rudimentary framework of wing veins is sufficient to restore the ability of flexible wings to generate forces at near-rigid values. Thus, the magnitude of force generation can be controlled by modulating the trailing edge flexibility and thereby controlling the magnitude of the leading edge vorticity. To characterize this, we have generated a detailed database of aerodynamic forces as a function of several variables including material properties, kinematics, aerodynamic forces and centre of pressure, which can also be used to help validate computational models of aeroelastic flapping wings. These experiments will also be useful for wing design for small

  4. Aerodynamic effects of flexibility in flapping wings

    PubMed Central

    Zhao, Liang; Huang, Qingfeng; Deng, Xinyan; Sane, Sanjay P.

    2010-01-01

    Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast, wings flapping at high angles of attack generate stable leading edge vorticity, which persists throughout the duration of the stroke and enhances mean aerodynamic forces. Here, we show that aerodynamic forces can be controlled by altering the trailing edge flexibility of a flapping wing. We used a dynamically scaled mechanical model of flapping flight (Re ≈ 2000) to measure the aerodynamic forces on flapping wings of variable flexural stiffness (EI). For low to medium angles of attack, as flexibility of the wing increases, its ability to generate aerodynamic forces decreases monotonically but its lift-to-drag ratios remain approximately constant. The instantaneous force traces reveal no major differences in the underlying modes of force generation for flexible and rigid wings, but the magnitude of force, the angle of net force vector and centre of pressure all vary systematically with wing flexibility. Even a rudimentary framework of wing veins is sufficient to restore the ability of flexible wings to generate forces at near-rigid values. Thus, the magnitude of force generation can be controlled by modulating the trailing edge flexibility and thereby controlling the magnitude of the leading edge vorticity. To characterize this, we have generated a detailed database of aerodynamic forces as a function of several variables including material properties, kinematics, aerodynamic forces and centre of pressure, which can also be used to help validate computational models of aeroelastic flapping wings. These experiments will also be useful for wing design for small robotic

  5. A low-cost simulation platform for flapping wing MAVs

    NASA Astrophysics Data System (ADS)

    Kok, J. M.; Chahl, J. S.

    2015-03-01

    This paper describes the design of a flight simulator for analysing the systems level performance of a Dragonfly-Inspired Micro Air Vehicle (DIMAV). A quasi-steady blade element model is used to analyse the aerodynamic forces. Aerodynamic and environmental forces are then incorporated into a real world flight dynamics model to determine the dynamics of the DIMAV system. The paper also discusses the implementation of the flight simulator for analysing the manoeuvrability of a DIMAV, specifically several modes of flight commonly found in dragonflies. This includes take-off, roll turns and yaw turns. Our findings with the simulator are consistent with results from wind tunnel studies and slow motion cinematography of dragonflies. In the take-off mode of flight, we see a strong dependence of take-off accelerations with flapping frequency. An increase in wing-beat frequency of 10% causes the maximum vertical acceleration to increase by 2g which is similar to that of dragonflies in nature. For the roll and yaw modes of manoeuvring, asymmetrical inputs are applied between the left and right set of wings. The flapping amplitude is increased on the left pair of wings which causes a time averaged roll rate to the right of 1.76rad/s within two wing beats. In the yaw mode, the stroke plane angle is reduced in the left pair of wings to initiate the yaw manoeuvre. In two wing beats, the time averaged yaw rate is 2.54rad/s.

  6. Biofluiddynamic scaling of flapping, spinning and translating fins and wings.

    PubMed

    Lentink, David; Dickinson, Michael H

    2009-08-01

    Organisms that swim or fly with fins or wings physically interact with the surrounding water and air. The interactions are governed by the morphology and kinematics of the locomotory system that form boundary conditions to the Navier-Stokes (NS) equations. These equations represent Newton's law of motion for the fluid surrounding the organism. Several dimensionless numbers, such as the Reynolds number and Strouhal number, measure the influence of morphology and kinematics on the fluid dynamics of swimming and flight. There exists, however, no coherent theoretical framework that shows how such dimensionless numbers of organisms are linked to the NS equation. Here we present an integrated approach to scale the biological fluid dynamics of a wing that flaps, spins or translates. Both the morphology and kinematics of the locomotory system are coupled to the NS equation through which we find dimensionless numbers that represent rotational accelerations in the flow due to wing kinematics and morphology. The three corresponding dimensionless numbers are (1) the angular acceleration number, (2) the centripetal acceleration number, and (3) the Rossby number, which measures Coriolis acceleration. These dimensionless numbers consist of length scale ratios, which facilitate their geometric interpretation. This approach gives fundamental insight into the physical mechanisms that explain the differences in performance among flapping, spinning and translating wings. Although we derived this new framework for the special case of a model fly wing, the method is general enough to make it applicable to other organisms that fly or swim using wings or fins.

  7. The dog-ear flap as an alternative for breast reconstruction in patients who have already undergone a DIEAP flap.

    PubMed

    Colebunders, Britt; Depypere, Bernard; Van Landuyt, Koenraad

    2016-05-01

    Breast reconstruction in patients who have previously undergone deep inferior epigastric artery perforator flap (DIEAP) reconstruction or abdominoplasty is often challenging. Depending on patients' body habitus, several second-choice flaps have been described such as the transverse upper gracilis (TUG) flap, profundus femoris artery perforator (PFAP) flap, superior gluteal artery perforator (SGAP) flap, and lumbar artery perforator (LAP) flap. Patients who have undergone a DIEAP flap reconstruction or abdominoplasty occasionally present with dog ears on both sides of the abdominal scar. The adipose tissue and skin of these dog ears are supplied by perforators of the deep circumflex iliac artery (DCIA). The DCIA flap was first described in 1979 by Taylor. We introduce this abdominal "dog-ear" flap for autologous breast reconstruction. PMID:26951847

  8. Motion Sickness

    MedlinePlus

    ... people traveling by car, train, airplanes and especially boats. Motion sickness can start suddenly, with a queasy ... motion sickness. For example, down below on a boat, your inner ear senses motion, but your eyes ...

  9. Lower Extremity Strength and Active Range of Motion in College Baseball Pitchers: A Comparison between Stance Leg and Kick Leg.

    PubMed

    Tippett, S R

    1986-01-01

    The role of the lower extremities and torso is vital in the pitching mechanism. However, a review of the literature reveals information primarily dealing with the upper extremity's role in throwing. This pilot study was conducted to: 1) determine selected lower extremity strength and range of motion measurements in sixteen college baseball pitchers, and 2) compare measurements in the stance leg to the kick leg. When preseason profiling is not possible, clinical norms for those treating college pitchers can be valuable in proper rehabilitation of the lower extremity. Also, by determining trends in lower extremity strength and motion when comparing kick (plant) leg to stance (drive) leg, a better understanding of lower extremity kinematics in the pitching act can be appreciated. Statistically significant differences were found in the active range of motion in plantarflexion, hip internal rotation, and hip extension of the stance leg, as well as hip flexion of the kick leg. lsokinetic evaluations at slow and fast speeds revealed significant differences in the strength of ankle dorsiflexors and hip flexors at slow speeds of the kick leg. Strength of the hamstrings on the kick leg was significant at fast speeds as was strength of the hip external rotators on the stance leg. J Orthop Sports Phys Ther 1986;8(1):10-14.

  10. Kinematic control of aerodynamic forces on an inclined flapping wing with asymmetric strokes.

    PubMed

    Park, Hyungmin; Choi, Haecheon

    2012-03-01

    In the present study, we conduct an experiment using a one-paired dynamically scaled model of an insect wing, to investigate how asymmetric strokes with different wing kinematic parameters are used to control the aerodynamics of a dragonfly-like inclined flapping wing in still fluid. The kinematic parameters considered are the angles of attack during the mid-downstroke (α(md)) and mid-upstroke (α(mu)), and the duration (Δτ) and time of initiation (τ(p)) of the pitching rotation. The present dragonfly-like inclined flapping wing has the aerodynamic mechanism of unsteady force generation similar to those of other insect wings in a horizontal stroke plane, but the detailed effect of the wing kinematics on the force control is different due to the asymmetric use of the angle of attack during the up- and downstrokes. For example, high α(md) and low α(mu) produces larger vertical force with less aerodynamic power, and low α(md) and high α(mu) is recommended for horizontal force (thrust) production. The pitching rotation also affects the aerodynamics of a flapping wing, but its dynamic rotational effect is much weaker than the effect from the kinematic change in the angle of attack caused by the pitching rotation. Thus, the influences of the duration and timing of pitching rotation for the present inclined flapping wing are found to be very different from those for a horizontal flapping wing. That is, for the inclined flapping motion, the advanced and delayed rotations produce smaller vertical forces than the symmetric one and the effect of pitching duration is very small. On the other hand, for a specific range of pitching rotation timing, delayed rotation requires less aerodynamic power than the symmetric rotation. As for the horizontal force, delayed rotation with low α(md) and high α(mu) is recommended for long-duration flight owing to its high efficiency, and advanced rotation should be employed for hovering flight for nearly zero horizontal force. The

  11. Kinematic control of aerodynamic forces on an inclined flapping wing with asymmetric strokes.

    PubMed

    Park, Hyungmin; Choi, Haecheon

    2012-03-01

    In the present study, we conduct an experiment using a one-paired dynamically scaled model of an insect wing, to investigate how asymmetric strokes with different wing kinematic parameters are used to control the aerodynamics of a dragonfly-like inclined flapping wing in still fluid. The kinematic parameters considered are the angles of attack during the mid-downstroke (α(md)) and mid-upstroke (α(mu)), and the duration (Δτ) and time of initiation (τ(p)) of the pitching rotation. The present dragonfly-like inclined flapping wing has the aerodynamic mechanism of unsteady force generation similar to those of other insect wings in a horizontal stroke plane, but the detailed effect of the wing kinematics on the force control is different due to the asymmetric use of the angle of attack during the up- and downstrokes. For example, high α(md) and low α(mu) produces larger vertical force with less aerodynamic power, and low α(md) and high α(mu) is recommended for horizontal force (thrust) production. The pitching rotation also affects the aerodynamics of a flapping wing, but its dynamic rotational effect is much weaker than the effect from the kinematic change in the angle of attack caused by the pitching rotation. Thus, the influences of the duration and timing of pitching rotation for the present inclined flapping wing are found to be very different from those for a horizontal flapping wing. That is, for the inclined flapping motion, the advanced and delayed rotations produce smaller vertical forces than the symmetric one and the effect of pitching duration is very small. On the other hand, for a specific range of pitching rotation timing, delayed rotation requires less aerodynamic power than the symmetric rotation. As for the horizontal force, delayed rotation with low α(md) and high α(mu) is recommended for long-duration flight owing to its high efficiency, and advanced rotation should be employed for hovering flight for nearly zero horizontal force. The

  12. Using motion-sensor camera technology to infer seasonal activity and thermal niche of the desert tortoise (Gopherus agassizii)

    USGS Publications Warehouse

    Agha, Mickey; Augustine, Benjamin; Lovich, Jeffrey E.; Delaney, David F.; Sinervo, Barry; Murphy, Mason O.; Ennen, Joshua R.; Briggs, Jessica R.; Cooper, Robert J.; Price, Steven J.

    2015-01-01

    Understanding the relationships between environmental variables and wildlife activity is an important part of effective management. The desert tortoise (Gopherus agassizii), an imperiled species of arid environments in the southwest US, may have increasingly restricted windows for activity due to current warming trends. In summer 2013, we deployed 48 motion sensor cameras at the entrances of tortoise burrows to investigate the effects of temperature, sex, and day of the year on the activity of desert tortoises. Using generalized estimating equations, we found that the relative probability of activity was associated with temperature (linear and quadratic), sex, and day of the year. Sex effects showed that male tortoises are generally more active than female tortoises. Temperature had a quadratic effect, indicating that tortoise activity was heightened at a range of temperatures. In addition, we found significant support for interactions between sex and day of the year, and sex and temperature as predictors of the probability of activity. Using our models, we were able to estimate air temperatures and times (days and hours) that were associated with maximum activity during the study. Because tortoise activity is constrained by environmental conditions such as temperature, it is increasingly vital to conduct studies on how tortoises vary their activity throughout the Sonoran Desert to better understand the effects of a changing climate.

  13. Using motion-sensor camera technology to infer seasonal activity and thermal niche of the desert tortoise (Gopherus agassizii).

    PubMed

    Agha, Mickey; Augustine, Benjamin; Lovich, Jeffrey E; Delaney, David; Sinervo, Barry; Murphy, Mason O; Ennen, Joshua R; Briggs, Jessica R; Cooper, Robert; Price, Steven J

    2015-01-01

    Understanding the relationships between environmental variables and wildlife activity is an important part of effective management. The desert tortoise (Gopherus agassizii), an imperiled species of arid environments in the southwest US, may have increasingly restricted windows for activity due to current warming trends. In summer 2013, we deployed 48 motion sensor cameras at the entrances of tortoise burrows to investigate the effects of temperature, sex, and day of the year on the activity of desert tortoises. Using generalized estimating equations, we found that the relative probability of activity was associated with temperature (linear and quadratic), sex, and day of the year. Sex effects showed that male tortoises are generally more active than female tortoises. Temperature had a quadratic effect, indicating that tortoise activity was heightened at a range of temperatures. In addition, we found significant support for interactions between sex and day of the year, and sex and temperature as predictors of the probability of activity. Using our models, we were able to estimate air temperatures and times (days and hours) that were associated with maximum activity during the study. Because tortoise activity is constrained by environmental conditions such as temperature, it is increasingly vital to conduct studies on how tortoises vary their activity throughout the Sonoran Desert to better understand the effects of a changing climate.

  14. Shape, flapping and flexion: wing and fin design for forward flight.

    PubMed

    Combes, S A; Daniel, T L

    2001-06-01

    Both kinematics and morphology are critical determinants of performance in flapping flight. However, the functional consequences of changes in these traits are not yet well understood. Traditional aerodynamic studies of planform wing shape have suggested that high-aspect-ratio wings generate more force per area and perform more efficiently than low-aspect-ratio wings, but these analyses may neglect critical components of flapping flight such as unsteady fluid dynamics and wing or fin flexion. In this paper, we use an unsteady potential flow analysis that incorporates wing flexion to test predictions of optimal wing shape under varying degrees of unsteady motion and wing flexion. We focus on forward flapping flight and examine the effects of wing/fin morphology and movements on thrust generation and efficiency. We test the model by comparing our predictions with kinematic data derived from the aquatic flight of the ratfish Hydrolagus colliei. Our analyses show that aspect ratio and the proportion of area in the outer one-fifth of the wing can characterize wing shape in terms of aero- or hydrodynamic performance. By comparing the performance of wings that vary in these two parameters, we find that traditional predictions of optimal wing shape are valid only under limited circumstances (when flapping frequency is low, wings are stiff or wings are tapered at the tips). This indicates a complex relationship between locomotor traits and performance and helps explain the diversity of wing kinematics and morphologies observed in nature.

  15. Using adjoint-based optimization to study wing flexibility in flapping flight

    NASA Astrophysics Data System (ADS)

    Wei, Mingjun; Xu, Min; Dong, Haibo

    2014-11-01

    In the study of flapping-wing flight of birds and insects, it is important to understand the impact of wing flexibility/deformation on aerodynamic performance. However, the large control space from the complexity of wing deformation and kinematics makes usual parametric study very difficult or sometimes impossible. Since the adjoint-based approach for sensitivity study and optimization strategy is a process with its cost independent of the number of input parameters, it becomes an attractive approach in our study. Traditionally, adjoint equation and sensitivity are derived in a fluid domain with fixed solid boundaries. Moving boundary is only allowed when its motion is not part of control effort. Otherwise, the derivation becomes either problematic or too complex to be feasible. Using non-cylindrical calculus to deal with boundary deformation solves this problem in a very simple and still mathematically rigorous manner. Thus, it allows to apply adjoint-based optimization in the study of flapping wing flexibility. We applied the ``improved'' adjoint-based method to study the flexibility of both two-dimensional and three-dimensional flapping wings, where the flapping trajectory and deformation are described by either model functions or real data from the flight of dragonflies. Supported by AFOSR.

  16. Comparing semilunar coronally positioned flap to standard coronally positioned flap using periodontal clinical parameters.

    PubMed

    Nassar, Carlos Augusto; da Silva, Wilson Aparecido Dias; Tonet, Karine; Secundes, Mayron Barros; Nassar, Patricia Oehlmeyer

    2014-01-01

    This study compared the effectiveness of 2 surgical root coverage techniques--semilunar coronally positioned flap and coronally advanced flap--using the clinical parameters of periodontal tissues from patients with Miller Class I gingival recession. Twenty patients (20-50 years of age) were selected. Basic periodontal treatment was performed, and plaque index, gingival index, probing depth, clinical attachment level, and height of the attached gingiva were determined. Each patient was placed into 1 of 2 groups: Group 1 patients underwent the semilunar coronally positioned flap technique, and Group 2 patients underwent the coronally advanced flap technique. Patients were assessed for 180 days. Both groups showed significant reduction of plaque and gingival indices and an improvement in clinical attachment levels and probing depth. However, results showed the standard coronally positioned flap technique was deemed more effective due to significant clinical attachment level gains. PMID:24598495

  17. Blade-Mounted Flap Control for BVI Noise Reduction Proof-of-Concept Test

    NASA Technical Reports Server (NTRS)

    Dawson, Seth; Hassan, Ahmed; Straub, Friedrich; Tadghighi, Hormoz

    1995-01-01

    This report describes a wind tunnel test of the McDonnell Douglas Helicopter Systems (MDHS) Active Flap Model Rotor at the NASA Langley 14- by 22-Foot Subsonic Tunnel. The test demonstrated that BVI noise reductions and vibration reductions were possible with the use of an active flap. Aerodynamic results supported the acoustic data trends, showing a reduction in the strength of the tip vortex with the deflection of the flap. Acoustic results showed that the flap deployment, depending on the peak deflection angle and azimuthal shift in its deployment schedule, can produce BVI noise reductions as much as 6 dB on the advancing and retreating sides. The noise reduction was accompanied by an increase in low frequency harmonic noise and high frequency broadband noise. A brief assessment of the effect of the flap on vibration showed that significant reductions were possible. The greatest vibration reductions (as much as 76%) were found in the four per rev pitching moment at the hub. Performance improvement cam results were inconclusive, as the improvements were predicted to be smaller than the resolution of the rotor balance.

  18. Aerodynamic flight performance in flap-gliding birds and bats.

    PubMed

    Muijres, Florian T; Henningsson, Per; Stuiver, Melanie; Hedenström, Anders

    2012-08-01

    Many birds use a flight mode called undulating or flap-gliding flight, where they alternate between flapping and gliding phases, while only a few bats make use of such a flight mode. Among birds, flap-gliding is commonly used by medium to large species, where it is regarded to have a lower energetic cost than continuously flapping flight. Here, we introduce a novel model for estimating the energetic flight economy of flap-gliding animals, by determining the lift-to-drag ratio for flap-gliding based on empirical lift-to-drag ratio estimates for continuous flapping flight and for continuous gliding flight, respectively. We apply the model to flight performance data of the common swift (Apus apus) and of the lesser long-nosed bat (Leptonycteris yerbabuenae). The common swift is a typical flap-glider while-to the best of our knowledge-the lesser long-nosed bat does not use flap-gliding. The results show that, according to the model, the flap-gliding common swift saves up to 15% energy compared to a continuous flapping swift, and that this is primarily due to the exceptionally high lift-to-drag ratio in gliding flight relative to that in flapping flight for common swifts. The lesser long-nosed bat, on the other hand, seems not to be able to reduce energetic costs by flap-gliding. The difference in relative costs of flap-gliding flight between the common swift and the lesser long-nosed bat can be explained by differences in morphology, flight style and wake dynamics. The model presented here proves to be a valuable tool for estimating energetic flight economy in flap-gliding animals. The results show that flap-gliding flight that is naturally used by common swifts is indeed the most economic one of the two flight modes, while this is not the case for the non-flap-gliding lesser long-nosed bat.

  19. Extended thoracodorsal artery perforator flap for breast reconstruction.

    PubMed

    Angrigiani, Claudio; Rancati, Alberto; Escudero, Ezequiel; Artero, Guillermo

    2015-12-01

    A total of 45 patients underwent partial or total autologous breast reconstruction after skin-sparing mastectomy, skin-reducing mastectomy, and quadrantectomy using a thoracodorsal artery perforator (TDAP) flap. The detailed surgical technique with its variations is explained in this report. The propeller, flip-over, conventional perforator, and muscle-sparing flaps have been described and evaluated. The flaps were partially or completely de-epithelialized. The conventional TDAP can be enlarged or "extended" as the traditional latissimus dorsi musculocutaneous (LD-MC) flap by incorporating the superior and inferior fat compartments. It can be referred to as the "extended TDAP flap". This technique augments the flap volume. In addition, this flap can serve as a scaffold for lipofilling to obtain autologous breast reconstruction in medium to large cases. There were two complete failures due to technical errors during flap elevation. Distal partial tissue suffering was observed in four flaps. These flaps were longer than usual; they reached the midline of the back. It is advisable to discard the distal medial quarter of the flap when it is designed up to the midline to avoid steatonecrosis or fibrosis. A retrospective analysis of the 39 flaps that survived completely revealed a satisfactory result in 82% of the cases. The main disadvantage of this procedure is the final scar. The TDAP flap is a reliable and safe method for partial or total breast autologous reconstruction. PMID:26645006

  20. The weight of computer mouse affects the wrist motion and forearm muscle activity during fast operation speed task.

    PubMed

    Chen, Han-Ming; Lee, Chang-Sian; Cheng, Chih-Hsiu

    2012-06-01

    The frequent use of the computer mouse was reported to be associated with the development of the musculoskeletal disorders in the wrist, forearm, and shoulder regions. This study was to examine the effect of the mouse weights and operation speeds on the wrist motion and muscle activity. 25 subjects (20 males and 5 females) were instructed to repetitively point-and-click the mouse between two targets displaced in the monitor with five different weighted mice (weights around 70, 100, 130, 160, and 190 g) at the fast (50 repetition/min) and slow (25 repetition/min) operation speeds. Surface electromyographic activity of the extensor carpi radialis, extensor carpi ulnaris, extensor digitorum, and upper trapezius muscles were recorded, and the electrogoniometer was used to register the wrist motions. The results showed that the maximal ulnar deviation was not significantly different among the examined conditions. The wrist movement range and the forearm muscle activities showed a V-shape tendency with the lowest value in the mouse weight of 130 g. This tendency was diminished during the slow speed tasks. The results suggested that the proper mouse weight could benefit the users in terms of increasing the movement efficiency and decreasing the muscular costs.

  1. Flow Structure on a Flapping Wing: Quasi-Steady Limit

    NASA Astrophysics Data System (ADS)

    Ozen, Cem; Rockwell, Donald

    2011-11-01

    The flapping motion of an insect wing typically involves quasi-steady motion between extremes of unsteady motion. This investigation characterizes the flow structure for the quasi-steady limit via a rotating wing in the form of a thin rectangular plate having a low aspect ratio (AR =1). Particle Image Velocimetry (PIV) is employed, in order to gain insight into the effects of centripetal and Coriolis forces. Vorticity, velocity and streamline patterns are used to describe the overall flow structure with an emphasis on the leading-edge vortex. A stable leading-edge vortex is maintained over effective angles of attack from 30° to 75° and it is observed that at each angle of attack the flow structure remains relatively same over the Reynolds number range from 3,600 to 14,500. The dimensionless circulation of the leading edge vortex is found to be proportional to the effective angle of attack. Quasi-three-dimensional construction of the flow structure is used to identify the different regimes along the span of the wing which is then complemented by patterns on cross flow planes to demonstrate the influence of root and tip swirls on the spanwise flow. The rotating wing results are also compared with the equivalent of translating wing to further illustrate the effects of the rotation.

  2. Three speech sounds, one motor action: Evidence for speech-motor disparity from English flap production

    PubMed Central

    Derrick, Donald; Stavness, Ian; Gick, Bryan

    2015-01-01

    The assumption that units of speech production bear a one-to-one relationship to speech motor actions pervades otherwise widely varying theories of speech motor behavior. This speech production and simulation study demonstrates that commonly occurring flap sequences may violate this assumption. In the word “Saturday,” a sequence of three sounds may be produced using a single, cyclic motor action. Under this view, the initial upward tongue tip motion, starting with the first vowel and moving to contact the hard palate on the way to a retroflex position, is under active muscular control, while the downward movement of the tongue tip, including the second contact with the hard palate, results from gravity and elasticity during tongue muscle relaxation. This sequence is reproduced using a three-dimensional computer simulation of human vocal tract biomechanics and differs greatly from other observed sequences for the same word, which employ multiple targeted speech motor actions. This outcome suggests that a goal of a speaker is to produce an entire sequence in a biomechanically efficient way at the expense of maintaining parity within the individual parts of the sequence. PMID:25786960

  3. Reconstruction of active regular motion in amoeba extract: dynamic cooperation between sol and gel states.

    PubMed

    Nishigami, Yukinori; Ichikawa, Masatoshi; Kazama, Toshiya; Kobayashi, Ryo; Shimmen, Teruo; Yoshikawa, Kenichi; Sonobe, Seiji

    2013-01-01

    Amoeboid locomotion is one of the typical modes of biological cell migration. Cytoplasmic sol-gel conversion of an actomyosin system is thought to play an important role in locomotion. However, the mechanisms underlying sol-gel conversion, including trigger, signal, and regulating factors, remain unclear. We developed a novel model system in which an actomyosin fraction moves like an amoeba in a cytoplasmic extract. Rheological study of this model system revealed that the actomyosin fraction exhibits shear banding: the sol-gel state of actomyosin can be regulated by shear rate or mechanical force. Furthermore, study of the living cell indicated that the shear-banding property also causes sol-gel conversion with the same order of magnitude as that of shear rate. Our results suggest that the inherent sol-gel transition property plays an essential role in the self-regulation of autonomous translational motion in amoeba.

  4. Reconstruction of Active Regular Motion in Amoeba Extract: Dynamic Cooperation between Sol and Gel States

    PubMed Central

    Kazama, Toshiya; Kobayashi, Ryo; Shimmen, Teruo; Yoshikawa, Kenichi; Sonobe, Seiji

    2013-01-01

    Amoeboid locomotion is one of the typical modes of biological cell migration. Cytoplasmic sol–gel conversion of an actomyosin system is thought to play an important role in locomotion. However, the mechanisms underlying sol–gel conversion, including trigger, signal, and regulating factors, remain unclear. We developed a novel model system in which an actomyosin fraction moves like an amoeba in a cytoplasmic extract. Rheological study of this model system revealed that the actomyosin fraction exhibits shear banding: the sol–gel state of actomyosin can be regulated by shear rate or mechanical force. Furthermore, study of the living cell indicated that the shear-banding property also causes sol–gel conversion with the same order of magnitude as that of shear rate. Our results suggest that the inherent sol–gel transition property plays an essential role in the self-regulation of autonomous translational motion in amoeba. PMID:23940560

  5. Deltopectoral Flap in the Era of Microsurgery

    PubMed Central

    Chan, R. C. L.; Chan, J. Y. W.

    2014-01-01

    Background. Our study aimed to review the role of deltopectoral (DP) flap as a reconstructive option for defects in the head and neck region in the microvascular era. Methods. All patients who received DP flap reconstruction surgery at the Department of Surgery, Queen Mary Hospital, between 1999 and 2011 were recruited. Demographic data, indications for surgery, defect for reconstruction, and surgical outcomes were analyzed. Results. Fifty-four patients were included. All but two patients were operated for reconstruction after tumour resection. The remaining two patients were operated for necrotizing fasciitis and osteoradionecrosis. The majority of DP flaps were used to cover neck skin defect (63.0%). Other reconstructed defects included posterior pharyngeal wall (22.2%), facial skin defect (11.1%), and tracheal wall (3.7%). All donor sites were covered with partial thickness skin graft. Two patients developed partial flap necrosis at the tip and were managed conservatively. The overall flap survival rate was 96.3%. Conclusions. Albeit the technical advancements in microvascular surgery, DP still possesses multiple advantages (technical simplicity, reliable axial blood supply, large size, thinness, and pliability) which allows it to remain as a useful, reliable, and versatile surgical option for head and neck reconstruction. PMID:25374953

  6. The effects of lower extremity muscle activation and passive range of motion on single leg squat performance.

    PubMed

    Mauntel, Timothy C; Begalle, Rebecca L; Cram, Tyler R; Frank, Barnett S; Hirth, Christopher J; Blackburn, Troy; Padua, Darin A

    2013-07-01

    Knee valgus is a potential risk factor for lower extremity (LE) injuries. Clinical movement screenings and passive range of motion (PROM) measurements may help identify neuromuscular patterns, which contribute to knee valgus. The purpose of this study was to compare LE muscle activation and PROM between subjects who display visual medial knee displacement (MKD) during a single leg squat (SLS) and those who do not. We hypothesized that muscular activation and PROM would differ between the groups. Forty physically active adults (20 controls, 20 MKDs) participated in this study. Subjects completed 10 LE PROM assessments and performed 5 SLS trials while electromyography (EMG) data were collected from 8 LE muscles. Three separate multivariate analysis of variance were used to identify group differences in EMG data, muscle coactivation, and PROM. Results during the SLS indicated hip coactivation ratios revealed smaller gluteus medius to hip adductor (GMed:Hip Add) (p = 0.028) and gluteus maximus to hip adductor (GMax:Hip Add) coactivation ratios (p = 0.007) compared with the control group. Also, the MKD group displayed significantly less passive ankle dorsiflexion with the knee extended (p = 0.047) and flexed (p = 0.034), and greater talar glide motion (p = 0.012). The findings of this study indicate that MKD during a SLS seems to be influenced by decreased coactivation of the gluteal to the hip adductor muscles and restricted dorsiflexion. Therefore, conditioning, rehabilitation, and injury prevention programs should focus on decreasing hip adductor activity, increasing hip abductor and external rotator activity, and increasing ankle dorsiflexion in hopes to decrease the incidence of these injuries. PMID:23096063

  7. Complexity reduction in the H.264/AVC using highly adaptive fast mode decision based on macroblock motion activity

    NASA Astrophysics Data System (ADS)

    Abdellah, Skoudarli; Mokhtar, Nibouche; Amina, Serir

    2015-11-01

    The H.264/AVC video coding standard is used in a wide range of applications from video conferencing to high-definition television according to its high compression efficiency. This efficiency is mainly acquired from the newly allowed prediction schemes including variable block modes. However, these schemes require a high complexity to select the optimal mode. Consequently, complexity reduction in the H.264/AVC encoder has recently become a very challenging task in the video compression domain, especially when implementing the encoder in real-time applications. Fast mode decision algorithms play an important role in reducing the overall complexity of the encoder. In this paper, we propose an adaptive fast intermode algorithm based on motion activity, temporal stationarity, and spatial homogeneity. This algorithm predicts the motion activity of the current macroblock from its neighboring blocks and identifies temporal stationary regions and spatially homogeneous regions using adaptive threshold values based on content video features. Extensive experimental work has been done in high profile, and results show that the proposed source-coding algorithm effectively reduces the computational complexity by 53.18% on average compared with the reference software encoder, while maintaining the high-coding efficiency of H.264/AVC by incurring only 0.097 dB in total peak signal-to-noise ratio and 0.228% increment on the total bit rate.

  8. A Statistical Analysis of Activity-Based and Traditional Introductory Algebra Physics Using the Force and Motion Conceptual Evaluation

    NASA Astrophysics Data System (ADS)

    Trecia Markes, Cecelia

    2006-03-01

    With a three-year FIPSE grant, it has been possible at the University of Nebraska at Kearney (UNK) to develop and implement activity- based introductory physics at the algebra level. It has generally been recognized that students enter physics classes with misconceptions about motion and force. Many of these misconceptions persist after instruction. Pretest and posttest responses on the ``Force and Motion Conceptual Evaluation'' (FMCE) are analyzed to determine the effectiveness of the activity- based method of instruction relative to the traditional (lecture/lab) method of instruction. Data were analyzed to determine the following: student understanding at the beginning of the course, student understanding at the end of the course, how student understanding is related to the type of class taken, student understanding based on gender and type of class. Some of the tests used are the t-test, the chi-squared test, and analysis of variance. The results of these tests will be presented, and their implications will be discussed.

  9. 14 CFR 25.1511 - Flap extended speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap extended speed. 25.1511 Section 25... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so that it does not exceed the design flap speed V F chosen under §§ 25.335(e) and 25.345, for...

  10. 14 CFR 25.1511 - Flap extended speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flap extended speed. 25.1511 Section 25... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so that it does not exceed the design flap speed V F chosen under §§ 25.335(e) and 25.345, for...

  11. 14 CFR 25.1511 - Flap extended speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flap extended speed. 25.1511 Section 25... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so that it does not exceed the design flap speed V F chosen under §§ 25.335(e) and 25.345, for...

  12. 14 CFR 25.1511 - Flap extended speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Flap extended speed. 25.1511 Section 25... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so that it does not exceed the design flap speed V F chosen under §§ 25.335(e) and 25.345, for...

  13. 14 CFR 25.1511 - Flap extended speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flap extended speed. 25.1511 Section 25... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so that it does not exceed the design flap speed V F chosen under §§ 25.335(e) and 25.345, for...

  14. Calculation of the longitudinal aerodynamic characteristics of wing-flap configurations with externally blown flaps

    NASA Technical Reports Server (NTRS)

    Mendenhall, M. R.; Spangler, S. B.; Nielsen, J. N.; Goodwin, F. K.

    1976-01-01

    A theoretical investigation was carried out to extend and improve an existing method for predicting the longitudinal characteristics of wing flap configurations with externally blown flaps (EBF). Two potential flow models were incorporated into the prediction method: a wing and flap lifting-surface model and a turbofan engine wake model. The wing-flap model uses a vortex-lattice approach to represent the wing and flaps. The jet wake model consists of a series of closely spaced vortex rings normal to a centerline which may have vertical and lateral curvature to conform to the local flow field beneath the wing and flaps. Comparisons of measured and predicted pressure distributions, span load distributions on each lifting surface, and total lift and pitching moment coefficients on swept and unswept EBF configurations are included. A wide range of thrust coefficients and flap deflection angles is considered at angles of attack up to the onset of stall. Results indicate that overall lift and pitching-moment coefficients are predicted reasonably well over the entire range. The predicted detailed load distributions are qualitatively correct and show the peaked loads at the jet impingement points, but the widths and heights of the load peaks are not consistently predicted.

  15. Vortex Loop Topology During the Stroke Reversal of a Flapping Wing

    NASA Astrophysics Data System (ADS)

    Burge, Matthew; Wysochanski, Clara; Ringuette, Matthew

    2015-11-01

    The effect of kinematic variations on the instantaneous 3-D flow structures formed during stroke-reversal of a 2-degree-of-freedom flapping wing in hover is investigated. Previous work correlates large force and circulation peaks to unsteady motion kinematics, but information from experiments detailing the instantaneous, 3-D flow-structure evolution is lacking. The objective of this work is to generate the vortex topology of a flapping wing in hover and qualitatively study the flow-structure trajectories with multi-color dye-flow visualization. Pure pitching and fixed angle of attack rotation are first examined to identify the vortices produced by each degree-of-freedom separately. For flapping motions, the stroke-reversal phase during various rotational accelerations for a constant pitching reduced frequency is studied, emphasizing vortex interactions and re-connectivity of time-elapsed vortex loops. The flow features are visualized using a scaled wing model in water with an internal dye-manifold, and captured using 2 orthogonal cameras. Motivation exists for both symmetric and advanced timing of the pitching with respect to stroke-reversal, and both are compared against pitching reduced frequency to characterize the 3-D loop structures responsible for lift generation. This work is supported by the National Science Foundation, Award Number 1336548, supervised by Dr. Dimitrios Papavassiliou.

  16. A numerical study on the effect of sweep angle on flapping-wing flight using fluid-structure interaction analysis

    NASA Astrophysics Data System (ADS)

    Kim, Dae-Kwan; Lee, Jun-Seong; Han, Jae-Hung

    2009-07-01

    The sweep-back effect of a flexible flapping wing is investigated through fluid-structure interaction analysis. The aeroelastic analysis is carried out by using an efficient fluid-structure interaction analysis tool, which is based on the modified strip theory and the flexible multibody dynamics. To investigate the sweep-back effect, the aeroelastic analysis is performed on various sweep-back wing models defined by sweep-chord ratio and sweep-span ratio, and then the sweep-back effect on the aerodynamic performance is discussed. The aeroelastic results of the sweep-back wing analysis clearly confirm that the sweep-back angle can help a flexible flapping wing to generate greater twisting motion, resulting in the aerodynamic improvement of thrust and input power for all flapping-axis angle regimes. The propulsive efficiency can also be increased by the sweep-back effect. The sweep angle of a flapping wing should be considered as an important design feature for artificial flexible flapping wings.

  17. Reconstruction of eyelids with Washio flap in anophthalmia.

    PubMed

    Tvrdek, M; Kozák, J

    2014-01-01

    The authors present a case report of a patient with anophthalmia in whom retroauriculo-temporal flap (Washio flap) was used for reconstruction of eyelids. This flap, which is mostly used for reconstructions of nasal defects, was not used in this way according to available literature.

  18. Flap Thickness in Eyes with Ectasia after LASIK

    PubMed Central

    Randleman, J. Bradley; Hebson, Carolyn B.; Larson, Paul M.

    2015-01-01

    Purpose To measure central flap thickness in eyes with ectasia after LASIK and to compare these values with estimated anticipated flap thickness based on average published values for each device used for flap creation. Setting Emory Vision at Emory University, Atlanta GA, USA Methods Confocal microscopic analysis using the Confoscan 3 (Nidek technologies) to measure central flap thickness in eyes with ectasia after LASIK, and evaluation of pre-LASIK records, including basic patient demographics, preoperative corneal topographies, estimated anticipated flap thickness based on published average thickness values, and residual stromal bed thickness (RSB) calculations using both measured and estimated flap thicknesses. Results Fifty eyes from 29 patients were evaluated. Average measured flap thickness was (138 ± 26 μ, range 90 to 220 μ). There were no significant differences between measured and estimated flap thicknesses (138 vs. 135 μ, p = 0.5) or RSB (329 vs. 332 μ, p = 0.7), nor were there any differences in flap thickness between eyes with normal or abnormal corneal topographies. Only one eye had a measured flap resulting in unintended RSB < 250 microns; this occurred in an eye with abnormal topography. Conclusions Measured central flap thickness was not thicker than estimated for the vast majority of eyes developing ectasia after LASIK. Thus, excessively thick flaps do not appear to be a major contributing factor to the pathogenesis of ectasia after LASIK. PMID:22424807

  19. The distally based forearm island flap in hand reconstruction.

    PubMed

    Jeng, S F; Wei, F C

    1998-08-01

    The distally based forearm island flap is vascularized by the perforators of the distal radial artery. The skin flap is along the axis of the radial artery, and the pivot point of its subcutaneous pedicle is about 2 to 4 cm above the radial styloid process. We have treated 12 patients with 12 flaps for soft-tissue defects of the hand. Of these recipient sites, seven were in dorsal hands, two were in thumbs, two were in forearms, and one was in the palmar area. The donor-tissue variants included eight skin flaps, two adipofascial flaps, and two sensate flaps. The sizes of the flaps ranged from 6 x 4 cm to 14 x 6 cm. The donor site wound could be closed primarily in five patients. Two sensate flaps, innervated by the lateral antebrachial cutaneous nerve, could provide sensation for thumb reconstruction. The advantage of this flap is its constant and reliable blood supply without sacrifice of the main radial artery. The elevation of the flap is simple and rapid. There is the potential that this flap can be used as an innervated flap, and there is no need of microsurgical technique.

  20. Sural Versus Perforator Flaps for Distal Medial Leg Wounds.

    PubMed

    Schannen, Andrew P; Truchan, Lisa; Goshima, Kaoru; Bentley, Roger; DeSilva, Gregory L

    2015-12-01

    Soft tissue coverage of distal medial ankle wounds is a challenging problem in orthopedic surgery because of the limited local tissues and prominent instrumentation. Traditionally, these wounds required free tissue transfer to achieve suitable coverage and subsequent bony union. To better respect the reconstructive ladder and to avoid the inherent difficulty of free flap coverage, rotational flaps have been used to cover these wounds. Both sural fasciocutaneous flaps and rotational fasciocutaneous perforator (propeller) flaps have been described for distal medial soft tissue coverage. The authors performed a retrospective chart review of patients who underwent distal medial leg coverage with the use of either sural flaps or rotational fasciocutaneous perforator flaps. The authors identified 14 patients by Current Procedural Terminology code who met the study criteria. The average age and degree of medical comorbidities were comparable in the 2 groups. The authors reviewed their medical records to evaluate fracture healing, flap size, complications, and return to normal shoe wear. All 7 sural flaps healed without incident, with underlying fracture healing. Of the 7 perforator flaps, 6 healed without incident, with underlying fracture healing. One perforator-based flap was complicated by superficial tip necrosis and went on to heal with local wound care. All patients returned to normal shoe wear. Both sural artery rotational flaps and posterior tibial artery-based rotational flaps are viable options for coverage of the distal medial leg. Coverage can be achieved reliably without microsurgery, anticoagulation, or monitoring in the intensive care unit. PMID:26652325

  1. 14 CFR 23.1511 - Flap extended speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it...

  2. 14 CFR 23.1511 - Flap extended speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it...

  3. 14 CFR 23.1511 - Flap extended speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it...

  4. 14 CFR 23.1511 - Flap extended speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it...

  5. 14 CFR 23.1511 - Flap extended speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it...

  6. Posttraumatic eyebrow reconstruction with hair-bearing temporoparietal fascia flap.

    PubMed

    Denadai, Rafael; Raposo-Amaral, Cassio Eduardo; Marques, Frederico Figueiredo; Raposo-Amaral, Cesar Augusto

    2015-01-01

    The temporoparietal fascia flap has been extensively used in craniofacial reconstructions. However, its use for eyebrow reconstruction has been sporadically reported. We describe a successfully repaired hair-bearing temporoparietal fascia flap after traumatic avulsion of eyebrow. Temporoparietal fascia flap is a versatile tool and should be considered as a therapeutic option by all plastic surgeons.

  7. 14 CFR 23.699 - Wing flap position indicator.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Wing flap position indicator. 23.699 Section 23.699 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap...

  8. 14 CFR 23.699 - Wing flap position indicator.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Wing flap position indicator. 23.699 Section 23.699 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap...

  9. 14 CFR 23.699 - Wing flap position indicator.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Wing flap position indicator. 23.699 Section 23.699 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap...

  10. 14 CFR 23.699 - Wing flap position indicator.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Wing flap position indicator. 23.699 Section 23.699 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap...

  11. 14 CFR 23.699 - Wing flap position indicator.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Wing flap position indicator. 23.699 Section 23.699 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap...

  12. Treatment of Ischial Pressure Sores with Both Profunda Femoris Artery Perforator Flaps and Muscle Flaps

    PubMed Central

    Kim, Chae Min; Yun, In Sik; Lee, Dong Won; Lew, Dae Hyun; Rah, Dong Kyun

    2014-01-01

    Background Reconstruction of ischial pressure sore defects is challenging due to extensive bursas and high recurrence rates. In this study, we simultaneously applied a muscle flap that covered the exposed ischium and large bursa with sufficient muscular volume and a profunda femoris artery perforator fasciocutaneous flap for the management of ischial pressure sores. Methods We retrospectively analyzed data from 14 patients (16 ischial sores) whose ischial defects had been reconstructed using both a profunda femoris artery perforator flap and a muscle flap between January 2006 and February 2014. We compared patient characteristics, operative procedure, and clinical course. Results All flaps survived the entire follow-up period. Seven patients (50%) had a history of surgery at the site of the ischial pressure sore. The mean age of the patients included was 52.8 years (range, 18-85 years). The mean follow-up period was 27.9 months (range, 3-57 months). In two patients, a biceps femoris muscle flap was used, while a gracilis muscle flap was used in the remaining patients. In four cases (25%), wound dehiscence occurred, but healed without further complication after resuturing. Additionally, congestion occurred in one case (6%), but resolved with conservative treatment. Among 16 cases, there was only one (6%) recurrence at 34 months. Conclusions The combination of a profunda femoris artery perforator fasciocutaneous flap and muscle flap for the treatment of ischial pressure sores provided pliability, adequate bulkiness and few long-term complications. Therefore, this may be used as an alternative treatment method for ischial pressure sores. PMID:25075362

  13. Flap effectiveness appraisal for winged re-entry vehicles

    NASA Astrophysics Data System (ADS)

    de Rosa, Donato; Pezzella, Giuseppe; Donelli, Raffaele S.; Viviani, Antonio

    2016-05-01

    The interactions between shock waves and boundary layer are commonplace in hypersonic aerodynamics. They represent a very challenging design issue for hypersonic vehicle. A typical example of shock wave boundary layer interaction is the flowfield past aerodynamic surfaces during control. As a consequence, such flow interaction phenomena influence both vehicle aerodynamics and aerothermodynamics. In this framework, the present research effort describes the numerical activity performed to simulate the flowfield past a deflected flap in hypersonic flowfield conditions for a winged re-entry vehicle.

  14. Motion mitigation for lung cancer patients treated with active scanning proton therapy

    SciTech Connect

    Grassberger, Clemens; Dowdell, Stephen; Sharp, Greg; Paganetti, Harald

    2015-05-15

    Purpose: Motion interplay can affect the tumor dose in scanned proton beam therapy. This study assesses the ability of rescanning and gating to mitigate interplay effects during lung treatments. Methods: The treatments of five lung cancer patients [48 Gy(RBE)/4fx] with varying tumor size (21.1–82.3 cm{sup 3}) and motion amplitude (2.9–30.6 mm) were simulated employing 4D Monte Carlo. The authors investigated two spot sizes (σ ∼ 12 and ∼3 mm), three rescanning techniques (layered, volumetric, breath-sampled volumetric) and respiratory gating with a 30% duty cycle. Results: For 4/5 patients, layered rescanning 6/2 times (for the small/large spot size) maintains equivalent uniform dose within the target >98% for a single fraction. Breath sampling the timing of rescanning is ∼2 times more effective than the same number of continuous rescans. Volumetric rescanning is sensitive to synchronization effects, which was observed in 3/5 patients, though not for layered rescanning. For the large spot size, rescanning compared favorably with gating in terms of time requirements, i.e., 2x-rescanning is on average a factor ∼2.6 faster than gating for this scenario. For the small spot size however, 6x-rescanning takes on average 65% longer compared to gating. Rescanning has no effect on normal lung V{sub 20} and mean lung dose (MLD), though it reduces the maximum lung dose by on average 6.9 ± 2.4/16.7 ± 12.2 Gy(RBE) for the large and small spot sizes, respectively. Gating leads to a similar reduction in maximum dose and additionally reduces V{sub 20} and MLD. Breath-sampled rescanning is most successful in reducing the maximum dose to the normal lung. Conclusions: Both rescanning (2–6 times, depending on the beam size) as well as gating was able to mitigate interplay effects in the target for 4/5 patients studied. Layered rescanning is superior to volumetric rescanning, as the latter suffers from synchronization effects in 3/5 patients studied. Gating minimizes the

  15. Motion mitigation for lung cancer patients treated with active scanning proton therapy

    PubMed Central

    Grassberger, Clemens; Dowdell, Stephen; Sharp, Greg; Paganetti, Harald

    2015-01-01

    Purpose: Motion interplay can affect the tumor dose in scanned proton beam therapy. This study assesses the ability of rescanning and gating to mitigate interplay effects during lung treatments. Methods: The treatments of five lung cancer patients [48 Gy(RBE)/4fx] with varying tumor size (21.1–82.3 cm3) and motion amplitude (2.9–30.6 mm) were simulated employing 4D Monte Carlo. The authors investigated two spot sizes (σ ∼ 12 and ∼3 mm), three rescanning techniques (layered, volumetric, breath-sampled volumetric) and respiratory gating with a 30% duty cycle. Results: For 4/5 patients, layered rescanning 6/2 times (for the small/large spot size) maintains equivalent uniform dose within the target >98% for a single fraction. Breath sampling the timing of rescanning is ∼2 times more effective than the same number of continuous rescans. Volumetric rescanning is sensitive to synchronization effects, which was observed in 3/5 patients, though not for layered rescanning. For the large spot size, rescanning compared favorably with gating in terms of time requirements, i.e., 2x-rescanning is on average a factor ∼2.6 faster than gating for this scenario. For the small spot size however, 6x-rescanning takes on average 65% longer compared to gating. Rescanning has no effect on normal lung V20 and mean lung dose (MLD), though it reduces the maximum lung dose by on average 6.9 ± 2.4/16.7 ± 12.2 Gy(RBE) for the large and small spot sizes, respectively. Gating leads to a similar reduction in maximum dose and additionally reduces V20 and MLD. Breath-sampled rescanning is most successful in reducing the maximum dose to the normal lung. Conclusions: Both rescanning (2–6 times, depending on the beam size) as well as gating was able to mitigate interplay effects in the target for 4/5 patients studied. Layered rescanning is superior to volumetric rescanning, as the latter suffers from synchronization effects in 3/5 patients studied. Gating minimizes the irradiated volume

  16. Numerical linearized MHD model of flapping oscillations

    NASA Astrophysics Data System (ADS)

    Korovinskiy, D. B.; Ivanov, I. B.; Semenov, V. S.; Erkaev, N. V.; Kiehas, S. A.

    2016-06-01

    Kink-like magnetotail flapping oscillations in a Harris-like current sheet with earthward growing normal magnetic field component Bz are studied by means of time-dependent 2D linearized MHD numerical simulations. The dispersion relation and two-dimensional eigenfunctions are obtained. The results are compared with analytical estimates of the double-gradient model, which are found to be reliable for configurations with small Bz up to values ˜ 0.05 of the lobe magnetic field. Coupled with previous results, present simulations confirm that the earthward/tailward growth direction of the Bz component acts as a switch between stable/unstable regimes of the flapping mode, while the mode dispersion curve is the same in both cases. It is confirmed that flapping oscillations may be triggered by a simple Gaussian initial perturbation of the Vz velocity.

  17. Functional resurfacing of the palm: flap selection based on defect analysis.

    PubMed

    Engelhardt, T O; Rieger, U M; Schwabegger, A H; Pierer, G

    2012-02-01

    Extensive defect coverage of the palm and anatomical reconstruction of its unique functional capacity remains difficult. In manual laborers, reconstruction of sensation, range of motion, grip strength but also mechanical stability is required. Sensate musculo-/fasciocutaneous flaps bear disadvantages of tissue mobility with shifting/bulkiness under stress. Thin muscle and fascial flaps show adherence but preclude sensory nerve coaptation. The purpose of this review is to present our algorithm for reliable selection of the most appropriate procedure based on defect analysis. Defect analysis focusing on units of tactile gnosis provides information to weigh needs for sensation or soft tissue stability. We distinguish radial unit (r)-thenar, ulnar unit (u)-hypothenar and unit (c)-central plus distal palm. Individual parameters need similar consideration to choose adequate treatment. Unit (r) and unit (u) are regions of secondary touch demanding protective sensation. Restoration of sensation using neurovascular, fasciocutaneous flaps is recommended. In unit (c), tactile gnosis is of less, mechanical resistance of greater value. Reconstruction of soft tissue resistance is suggested first in this unit. In laborers, free fascial- or muscle flaps with plantar instep skin grafts may achieve near to anatomical reconstruction with minimal sensation. Combined defects involving unit (c) require correlation with individual parameters for optimal flap selection. Defect coverage of the palm should not consist of merely providing sensate vascularized tissue. The most appropriate procedure should be derived from careful defect analysis to achieve near to anatomical reconstruction. In laborers, defect related demands need close correlation with sensation and mechanical stability to be expected. PMID:22121075

  18. Block-like motion of Tibetan Plateau: Evidences from active faults , GPS velocities and recent earthquake slips

    NASA Astrophysics Data System (ADS)

    Xu, X.; Cheng, J.

    2012-12-01

    continuous models have been proposed to explain GPS observations in many active regions. Here we first describe a division of active blocks in the Tibetan plateau and its adjacent regions in detail from recently published and unpublished maps showing distribution of active faults, discuss basic features of boundary faults around the blocks, block-like motions and their interior deformation patterns in the Quaternary. Then we examine present-day vectors and mechanical parameters of the active blocks both from the GPS observations and recent earthquake slips. All these analyses demonstrate that the block-like motion prevail in the Tibetan Plateau.

  19. Toying with Motion.

    ERIC Educational Resources Information Center

    Galus, Pamela J.

    2002-01-01

    Presents a variety of activities that support the development of an understanding of Newton's laws of motion. Activities use toy cars, mobile roads, and a seat-of-nails. Includes a scoring rubric. (DDR)

  20. Application of Hyperelastic-based Active Mesh Model in Cardiac Motion Recovery.

    PubMed

    Yousefi-Banaem, Hossein; Kermani, Saeed; Daneshmehr, Alireza; Saneie, Hamid

    2016-01-01

    Considering the nonlinear hyperelastic or viscoelastic nature of soft tissues has an important effect on modeling results. In medical applications, accounting nonlinearity begets an ill posed problem, due to absence of external force. Myocardium can be considered as a hyperelastic material, and variational approaches are proposed to estimate stiffness matrix, which take into account the linear and nonlinear properties of myocardium. By displacement estimation of some points in the four-dimensional cardiac magnetic resonance imaging series, using a similarity criterion, the elementary deformations are estimated, then using the Moore-Penrose inverse matrix approach, all point deformations are obtained. Using this process, the cardiac wall motion is quantized to mechanically determine local parameters to investigate the cardiac wall functionality. This process was implemented and tested over 10 healthy and 20 patients with myocardial infarction. In all patients, the process was able to precisely determine the affected region. The proposed approach was also compared with linear one and the results demonstrated its superiority respect to the linear model. PMID:27563570

  1. Active Flow Control of the Near Wake of an Axisymmetric Body in Prescribed Motion

    NASA Astrophysics Data System (ADS)

    Lambert, Thomas; Vukasinovic, Bojan; Glezer, Ari

    2014-11-01

    Controlled interactions between fluidic actuators and the cross flow over the aft end of a wire-mounted axisymmetric moving wind tunnel bluff body model are exploited for modification of its near wake and thereby its global unsteady aerodynamic loads. The model is supported by eight servo-controlled wires, each including a miniature inline force transducer for measurements of the time-resolved tension. The body moves along a prescribed trajectory controllable in six degrees of freedom using closed loop feedback from an external camera system. Actuation is effected by an integrated azimuthally-segmented array of four aft-facing synthetic jet modules around the perimeter of the tail end. In the present investigations, the aerodynamic loads are controlled during time-periodic axial and rotational motions with varying reduced frequencies of up to 0.259. It is shown that this flow control approach modifies the near wake and induces aerodynamic loads that are comparable to the baseline model dynamic loads. Control of the model's unsteady aerodynamic characteristics may be adopted for in flight stabilization.

  2. Application of Hyperelastic-based Active Mesh Model in Cardiac Motion Recovery

    PubMed Central

    Yousefi-Banaem, Hossein; Kermani, Saeed; Daneshmehr, Alireza; Saneie, Hamid

    2016-01-01

    Considering the nonlinear hyperelastic or viscoelastic nature of soft tissues has an important effect on modeling results. In medical applications, accounting nonlinearity begets an ill posed problem, due to absence of external force. Myocardium can be considered as a hyperelastic material, and variational approaches are proposed to estimate stiffness matrix, which take into account the linear and nonlinear properties of myocardium. By displacement estimation of some points in the four-dimensional cardiac magnetic resonance imaging series, using a similarity criterion, the elementary deformations are estimated, then using the Moore–Penrose inverse matrix approach, all point deformations are obtained. Using this process, the cardiac wall motion is quantized to mechanically determine local parameters to investigate the cardiac wall functionality. This process was implemented and tested over 10 healthy and 20 patients with myocardial infarction. In all patients, the process was able to precisely determine the affected region. The proposed approach was also compared with linear one and the results demonstrated its superiority respect to the linear model. PMID:27563570

  3. Myocardial metabolism, perfusion, wall motion and electrical activity in Duchenne muscular dystrophy

    SciTech Connect

    Perloff, J.K.; Henze, E.; Schelbert, H.R.

    1982-01-01

    The cardiomyopathy of Duchenne's muscular dystrophy originates in the posterobasal left ventricle and extends chiefly to the contiguous lateral wall. Ultrastructural abnormalities in these regions precede connective tissue replacement. We postulated that a metabolic fault coincided with or antedated the subcellular abnormality. Accordingly, regional left ventricular metabolism, perfusion and wall motion were studied using positron computed tomography and metabolic isotopes supplemented by thallium perfusion scans, equilibrium radionuclide angiography and M-mode and two-dimensional echocardiography. To complete the assessment, electrocardiograms, vectorcardiograms, 24 hour taped electrocardiograms and chest x-rays were analyzed. Positron computed tomography utilizing F-18 2-fluoro 2-deoxyglucose (FDG) provided the first conclusive evidence supporting the hypothesis of a premorphologic regional metabolic fault. Thus, cardiac involvement in duchenne dystrophy emerges as a unique form of heart disease, genetically targeting specific regions of ventricular myocardium for initial metabolic and subcellular changes. Reported ultrastructural abnormalities of the impulse and conduction systems provide, at least in part, a basis for the clinically observed sinus node, intraatrial, internodal, AV nodal and infranodal disorders.

  4. Using structure-from-motion for monitoring active lava flows and domes

    NASA Astrophysics Data System (ADS)

    James, Mike R.; Robson, Stuart; Varley, Nick

    2016-04-01

    3-D reconstruction software based on structure-from-motion (SfM) algorithms can substantially reduce the requirements and learning curve for generating topographic data from photographs, and thus offers strong potential for data collection in many dynamic environments. Unfortunately, SfM-based software tends not to provide the rigorous metrics that are used to assess the quality of results in conventional photogrammetry software. Here, we use examples of repeat oblique airborne acquisitions from a volcanic dome (Volcán de Colima, Mexico) and terrestrial time-lapse stereo-photography (Mt. Etna, Sicily) to examine the sensitivity of results to imaging characteristics and SfM processing procedures. At Volcán de Colima, photographs were acquired with a relatively favourable convergent geometry, from an opened window in a light aircraft. However, hazards prevent the deployment of ground control, so the derived topographic shape relies entirely on the image tie points generated automatically by the software. In contrast, at Mt. Etna, control targets could be used but, with only two (mildly convergent) cameras, the image geometry is naturally weaker that at Colima. We use both of these cases to explore some of the challenges involved with understanding the error inherent in projects processed using SfM-based approaches. Results are compared with those achieved using a rigorous close-range photogrammetry package.

  5. 50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE... AND ANADROMOUS SPECIES Pt. 223, Fig. 16 Figure 16 to Part 223—Escape Opening and Flap Dimensions...

  6. 50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE... AND ANADROMOUS SPECIES Pt. 223, Fig. 16 Figure 16 to Part 223—Escape Opening and Flap Dimensions...

  7. 50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 10 2014-10-01 2014-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES... for the Double Cover Flap TED ER02JN04.003...

  8. 50 CFR Figure 16 to Part 223 - Escape Opening and Flap Dimensions for the Double Cover Flap TED

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 10 2013-10-01 2013-10-01 false Escape Opening and Flap Dimensions for the Double Cover Flap TED 16 Figure 16 to Part 223 Wildlife and Fisheries NATIONAL MARINE FISHERIES... for the Double Cover Flap TED ER02JN04.003...

  9. A study of a three-dimensional self-propelled flying bird with flapping wings

    NASA Astrophysics Data System (ADS)

    Zhu, LinLin; Guan, Hui; Wu, ChuiJie

    2015-09-01

    In this paper, a study of a three-dimensional (3D) self-propelled bionic flying bird in a viscous flow is carried out. This bionic bird is propelled and lifted through flapping and rotating wings, and better flying can be achieved by adjusting the flapping and rotation motion of wings. In this study, we found that the bird can fly faster forward and upward with appropriate center of rotation and oscillation without more energy consumption and have perfect flight performance at a certain angle of attack by adjusting the center of oscillation. The study utilizes a 3D computational fluid dynamics package which constitutes combined immersed boundary method and the volume of fluid method. In addition, it includes adaptive multigrid finite volume method and control strategy of swimming and flying.

  10. Airplane wing leading edge variable camber flap

    NASA Technical Reports Server (NTRS)

    Cole, J. B.

    1980-01-01

    The invention and design of an aerodynamic high lift device which provided a solution to an aircraft performance problem are described. The performance problem of converting a high speed cruise airfoil into a low speed aerodynamic shape that would provide landing and take-off characteristics superior to those available with contemporary high lift devices are addressed. The need for an improved wing leading edge device that would complement the high lift performance of a triple slotted trailing edge flap is examined. The mechanical and structural aspects of the variable camber flap are discussed and the aerodynamic performance aspects only as they relate to the invention and design of the device are presented.

  11. Flap Edge Aeroacoustic Measurements and Predictions

    NASA Technical Reports Server (NTRS)

    Brooks, Thomas F.; Humphreys, William M., Jr.

    2000-01-01

    An aeroacoustic model test has been conducted to investigate the mechanisms of sound generation on high-lift wing configurations. This paper presents an analysis of flap side-edge noise, which is often the most dominant source. A model of a main element wing section with a half-span flap was tested at low speeds of up to a Mach number of 0.17, corresponding to a wing chord Reynolds number of approximately 1.7 million. Results are presented for flat (or blunt), flanged, and round flap-edge geometries, with and without boundary-layer tripping, deployed at both moderate and high flap angles. The acoustic database is obtained from a Small Aperture Directional Array (SADA) of microphones, which was constructed to electronically steer to different regions of the model and to obtain farfield noise spectra and directivity from these regions. The basic flap-edge aerodynamics is established by static surface pressure data, as well as by Computational Fluid Dynamics (CFD) calculations and simplified edge flow analyses. Distributions of unsteady pressure sensors over the flap allow the noise source regions to be defined and quantified via cross-spectral diagnostics using the SADA output. It is found that shear layer instability and related pressure scatter is the primary noise mechanism. For the flat edge flap, two noise prediction methods based on unsteady-surface-pressure measurements are evaluated and compared to measured noise. One is a new causality spectral approach developed here. The other is a new application of an edge-noise scatter prediction method. The good comparisons for both approaches suggest that much of the physics is captured by the prediction models. Areas of disagreement appear to reveal when the assumed edge noise mechanism does not fully define, the noise production. For the different edge conditions, extensive spectra and directivity are presented. Significantly, for each edge configuration, the spectra for different flow speeds, flap angles, and

  12. Forehead flap in maxillofacial surgery: Our experiences

    PubMed Central

    Ahmed, Syed S.; Ghassemi, Alireza; Rehman, Sajjad A.; Ansari, Md. Kaleem

    2015-01-01

    The forehead flap is a commonly used technique to reconstruct the deep and large nasal defects. It can be conveniently performed under local or general anesthesia and provides a very good color and texture matching to the nasal skin, which makes it a suitable graft harvesting site for nasal reconstruction. It has only single disadvantage disadvantagethat it is a two-stage procedure and “finishing” surgeries are needed occasionally for best surgical and cosmetic outcome. In this paper, we describe three different applications of forehead flaps. PMID:26668457

  13. Modeling and classifying human activities from trajectories using a class of space-varying parametric motion fields.

    PubMed

    Nascimento, Jacinto C; Marques, Jorge S; Lemos, João M

    2013-05-01

    Many approaches to trajectory analysis, such as clustering or classification, use probabilistic generative models, thus not requiring trajectory alignment/registration. Switched linear dynamical models (e.g., HMMs) have been used in this context, due to their ability to describe different motion regimes. However, these models are not suitable for handling space-dependent dynamics that are more naturally captured by nonlinear models. As is well known, these are more difficult to identify. In this paper, we propose a new way of modeling trajectories, based on a mixture of parametric motion vector fields that depend on a small number of parameters. Switching among these fields follows a probabilistic mechanism, characterized by a field of stochastic matrices. This approach allows representing a wide variety of trajectories and modeling space-dependent behaviors without using global nonlinear dynamical models. Experimental evaluation is conducted in both synthetic and real scenarios. The latter concerning with human trajectory modeling for activity classification, a central task in video surveillance.

  14. Three-dimensional motion estimation using genetic algorithms from image sequence in an active stereo vision system

    NASA Astrophysics Data System (ADS)

    Dipanda, Albert; Ajot, Jerome; Woo, Sanghyuk

    2003-06-01

    This paper proposes a method for estimating 3D rigid motion parameters from an image sequence of a moving object. The 3D surface measurement is achieved using an active stereovision system composed of a camera and a light projector, which illuminates objects to be analyzed by a pyramid-shaped laser beam. By associating the laser rays and the spots in the 2D image, the 3D points corresponding to these spots are reconstructed. Each image of the sequence provides a set of 3D points, which is modeled by a B-spline surface. Therefore, estimating the motion between two images of the sequence boils down to matching two B-spline surfaces. We consider the matching environment as an optimization problem and find the optimal solution using Genetic Algorithms. A chromosome is encoded by concatenating six binary coded parameters, the three angles of rotation and the x-axis, y-axis and z-axis translations. We have defined an original fitness function to calculate the similarity measure between two surfaces. The matching process is performed iteratively: the number of points to be matched grows as the process advances and results are refined until convergence. Experimental results with a real image sequence are presented to show the effectiveness of the method.

  15. Modeling and classifying human activities from trajectories using a class of space-varying parametric motion fields.

    PubMed

    Nascimento, Jacinto C; Marques, Jorge S; Lemos, João M

    2013-05-01

    Many approaches to trajectory analysis, such as clustering or classification, use probabilistic generative models, thus not requiring trajectory alignment/registration. Switched linear dynamical models (e.g., HMMs) have been used in this context, due to their ability to describe different motion regimes. However, these models are not suitable for handling space-dependent dynamics that are more naturally captured by nonlinear models. As is well known, these are more difficult to identify. In this paper, we propose a new way of modeling trajectories, based on a mixture of parametric motion vector fields that depend on a small number of parameters. Switching among these fields follows a probabilistic mechanism, characterized by a field of stochastic matrices. This approach allows representing a wide variety of trajectories and modeling space-dependent behaviors without using global nonlinear dynamical models. Experimental evaluation is conducted in both synthetic and real scenarios. The latter concerning with human trajectory modeling for activity classification, a central task in video surveillance. PMID:23380856

  16. A one year long continuous record of seismic activity and surface motion at the tongue of Rhonegletscher (Valais, Switzerland)

    NASA Astrophysics Data System (ADS)

    Dalban Canassy, Pierre; Röösli, Claudia; Walter, Fabian; Gabbi, Jeannette

    2014-05-01

    A critical gap in our current understanding of glaciers is how high sub-glacial water pressure controls the coupling of the glacier to its bed. Processes at the base of a glacier are inherently difficult to investigate due to their remoteness. Investigation of the sub-glacial environment with passive seismic methods is an innovative, rapidly growing interdisciplinary and promising endeavor. In combination with observations of surface motion and basal water pressure, this method is ideally suited to localize and quantify frictional and fracture processes which occur during periods of rapidly changing sub-glacial water pressure with consequent stress redistribution at the contact interface between ice and bed. Here we present the results of the first one-year-long glacier seismic monitoring performed on an Alpine glacier to our knowledge. Together with records of surface motion and hydrological measurements, we examine whether seasonal changes can be captured by seismic recording. Experiments were carried out from June 2012 to July 2013 on Rhonegletscher (Valais, Switzerland), by means of 3 three-components seismometers settled close to the tongue in 2 meters boreholes. An additional array of eleven sensors installed at the ice surface was also maintained during September 2012, in order to achieve more accurate icequakes locations. A high seismic emission is observed on Rhonegletscher, with icequakes located close to the surface or in the vicinity of the bedrock. The temporal distribution of seismic activity is shown to nicely reflect the seasonal evolution of the glacier hydrology, with a dramatic seismic release in early spring. During summer, released seismic activity is generally driven by diurnal ice/snow melting cycle. In winter, snow-cover conditions are associated with a reduced seismic release, with nevertheless some unexpected activity possibly related to snow-pack metamorphism. Based on icequake locations derived from data recorded in September, we discuss

  17. Motion-related artefacts in EEG predict neuronally plausible patterns of activation in fMRI data

    PubMed Central

    Jansen, Marije; White, Thomas P.; Mullinger, Karen J.; Liddle, Elizabeth B.; Gowland, Penny A.; Francis, Susan T.; Bowtell, Richard; Liddle, Peter F.

    2012-01-01

    The simultaneous acquisition and subsequent analysis of EEG and fMRI data is challenging owing to increased noise levels in the EEG data. A common method to integrate data from these two modalities is to use aspects of the EEG data, such as the amplitudes of event-related potentials (ERP) or oscillatory EEG activity, to predict fluctuations in the fMRI data. However, this relies on the acquisition of high quality datasets to ensure that only the correlates of neuronal activity are being studied. In this study, we investigate the effects of head-motion-related artefacts in the EEG signal on the predicted T2*-weighted signal variation. We apply our analyses to two independent datasets: 1) four participants were asked to move their feet in the scanner to generate small head movements, and 2) four participants performed an episodic memory task. We created T2*-weighted signal predictors from indicators of abrupt head motion using derivatives of the realignment parameters, from visually detected artefacts in the EEG as well as from three EEG frequency bands (theta, alpha and beta). In both datasets, we found little correlation between the T2*-weighted signal and EEG predictors that were not convolved with the canonical haemodynamic response function (cHRF). However, all convolved EEG predictors strongly correlated with the T2*-weighted signal variation in various regions including the bilateral superior temporal cortex, supplementary motor area, medial parietal cortex and cerebellum. The finding that movement onset spikes in the EEG predict T2*-weighted signal intensity only when the time course of movements is convolved with the cHRF, suggests that the correlated signal might reflect a BOLD response to neural activity associated with head movement. Furthermore, the observation that broad-spectral EEG spikes tend to occur at the same time as abrupt head movements, together with the finding that abrupt movements and EEG spikes show similar correlations with the T2

  18. [Aseptic bone flap osteonecrosis following cranioplasty after decompressive cranietomy].

    PubMed

    Smoll, Nicolas R; Stienen, Martin N; Schaller, Karl; Gautschi, Oliver P

    2013-06-19

    This case report discusses a case of aseptic osteonecrosis in a cranioplasty bone flap after decompressive craniectomy, which is a known, but rare complication after autologous cranioplasty. We suggest that the pathophysiology of cranial bone flap necrosis may have a similar pathophysiology to free flap necrosis/failure. The key suggested problem causing the osteonecrosis is vessel thrombosis within the smaller vessels of the bone flap due to the prothrombotic effects of the factors released during drilling of the bone flap. Suspicious local findings like wound dehiscence or fluid leakage should lead to a head computed tomography in order to discuss a prophylactic artificial second cranioplasty if necessary. PMID:23773942

  19. Activity monitoring and motion classification of the lizard Chamaeleo jacksonii using multiple Doppler radars.

    PubMed

    Singh, Aditya; Lee, Scott S K; Butler, Marguerite; Lubecke, Victor

    2012-01-01

    We describe a simple, non-contact and efficient tool for monitoring the natural activity of a small lizard (Chamaeleo jacksonii) to yield valuable information about their metabolic activity and energy expenditure. It allows monitoring in a non-confined laboratory environment and uses multiple Doppler radars operating at 10.525 GHz. We developed a classification algorithm that can differentiate between fidgeting and locomotion by processing the quadrature baseband signals from the radars. The results have been verified by visual inspection and indicate that the tool could also be used for automated monitoring of the activities of reptiles and other small animals. PMID:23366934

  20. Activity monitoring and motion classification of the lizard Chamaeleo jacksonii using multiple Doppler radars.

    PubMed

    Singh, Aditya; Lee, Scott S K; Butler, Marguerite; Lubecke, Victor

    2012-01-01

    We describe a simple, non-contact and efficient tool for monitoring the natural activity of a small lizard (Chamaeleo jacksonii) to yield valuable information about their metabolic activity and energy expenditure. It allows monitoring in a non-confined laboratory environment and uses multiple Doppler radars operating at 10.525 GHz. We developed a classification algorithm that can differentiate between fidgeting and locomotion by processing the quadrature baseband signals from the radars. The results have been verified by visual inspection and indicate that the tool could also be used for automated monitoring of the activities of reptiles and other small animals.