WorldWideScience

Sample records for active flap control

  1. Active Control of Long Bridges Using Flaps

    DEFF Research Database (Denmark)

    Hansen, H. I.; Thoft-Christensen, Palle

    The main problem in designing ultra-long span suspension bridges is flutter. A solution to this problem might be to introduce an active flap control system to increase the flutter wind velocity. The investigated flap control system consists of flaps integrated in the bridge girder so each flap...... is the streamlined part of the edge of the girder. Additional aerodynamic derivatives are shown for the flaps and it is shown how methods already developed can be used to estimate the flutter wind velocity for a bridge section with flaps. As an example, the flutter wind velocity is calculated for different flap...

  2. Rotor Flapping Response to Active Control

    Science.gov (United States)

    Nguyen, Khanh; Johnson, Wayne

    2004-01-01

    Rotor active control using higher harmonic blade pitch has been proposed as a means to reduce both rotor radiated noise and airframe vibration and to enhance rotor performance. The higher harmonic input, however, can affect rotor thrust and cyclic flapping - the basic trim characteristics of the rotor. Some of the trim changes can negate the active control benefits. For example, wind tunnel test results of a full scale BO-105 rotor with individual-blade control indicate some rotor performance improvements, accompanied with changes in rotor trim, using two-per-rev blade pitch input. The observed performance benefits could therefore be a simple manifestation of the trim change rather than an efficient redistribution of the rotor airloads. More recently, the flight test of the BO-105 helicopter equip,ped with individual-blade-control actuators also reported trim changes whenever the two-per-rev blade pitch for noise reduction was activated. The pilot had to adjust the trim control to maintain the aircraft under a constant flight path. These two cases highlight the, importance of trim considerations in the application of active control to rotorcraft.

  3. Stability investigation of an airfoil section with active flap control

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Gaunaa, Mac

    2010-01-01

    This work presents a method to determine flutter and divergence instability limits for a two-dimensional (2-D) airfoil section fitted with an actively controlled trailing edge flap. This flap consists of a deformable trailing edge, which deformation is governed by control algorithms based...... for fatigue load alleviation. The structural model of the 2-D airfoil section contains three degrees of freedom: heave translation, pitch rotation and flap deflection. A potential flow model provides the aerodynamic forces and their distribution. The unsteady aerodynamics are described using an indicial....... The implemented stability tool is then applied to an airfoil section representative of a wind turbine blade with active flap control. It is thereby observed that the airfoil stability limits are significantly modified by the presence of the flap, and they depend on several parameters: flap structural...

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

    Science.gov (United States)

    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.

  5. Positioning the 5'-flap junction in the active site controls the rate of flap endonuclease-1-catalyzed DNA cleavage

    KAUST Repository

    Song, Bo

    2018-02-09

    Flap endonucleases catalyze cleavage of single-stranded DNA flaps formed during replication, repair and recombination, and are therefore essential for genome processing and stability. Recent crystal structures of DNA-bound human flap endonuclease (hFEN1) offer new insights into how conformational changes in the DNA and hFEN1 may facilitate the reaction mechanism. For example, previous biochemical studies of DNA conformation performed under non-catalytic conditions with Ca2+ have suggested that base unpairing at the 5\\'-flap:template junction is an important step in the reaction, but the new structural data suggest otherwise. To clarify the role of DNA changes in the kinetic mechanism, we measured a series of transient steps - from substrate binding to product release - during the hFEN1-catalyzed reaction in the presence of Mg2+. We found that while hFEN1 binds and bends DNA at a fast, diffusion-limited rate, much slower Mg2+-dependent conformational changes in DNA around the active site are subsequently necessary and rate-limiting for 5\\'-flap cleavage. These changes are reported overall by fluorescence of 2-aminopurine at the 5\\'-flap:template junction, indicating that local DNA distortion (e.g., disruption of base stacking observed in structures), associated with positioning the 5\\'-flap scissile phosphodiester bond in the hFEN1 active site, controls catalysis. hFEN1 residues with distinct roles in the catalytic mechanism, including those binding metal ions (Asp-34, Asp-181), steering the 5\\'-flap through the active site and binding the scissile phosphate (Lys-93, Arg-100), and stacking against the base 5\\' to the scissile phosphate (Tyr-40), all contribute to these rate-limiting conformational changes, ensuring efficient and specific cleavage of 5\\'-flaps.

  6. Load alleviation potential of active flaps and individual pitch control in a full design load basis

    OpenAIRE

    Barlas, Athanasios; Bergami, Leonardo; Hansen, Morten Hartvig; Pedersen, Mads Mølgaard; Verelst, David Robert; Thomsen, Kenneth; Aagaard Madsen , Helge

    2015-01-01

    The load alleviation potential of the Controllable Rubber Trailing Edge Flap (CRTEF) is verified on a full Design Load Basis (DLB) setup using the aeroelastic code HAWC2, and by investigating a flap configuration for the NREL 5MW Reference Wind Turbine (RWT) model. The performance of the CRTEF configuration is evaluated by comparing four setups: 1) baseline with collective pitch, 2) individual pitch control, 3) individual flap control and 4) individual flap control combined with individual pi...

  7. Load alleviation potential of active flaps and individual pitch control in a full design load basis

    DEFF Research Database (Denmark)

    Barlas, Athanasios; Bergami, Leonardo; Hansen, Morten Hartvig

    2015-01-01

    configuration is evaluated by comparing four setups: 1) baseline with collective pitch, 2) individual pitch control, 3) individual flap control and 4) individual flap control combined with individual pitch control. The CRTEF allows for a significant reduction of the lifetime fatigue on various load channels......The load alleviation potential of the Controllable Rubber Trailing Edge Flap (CRTEF) is verified on a full Design Load Basis (DLB) setup using the aeroelastic code HAWC2, and by investigating a flap configuration for the NREL 5MW Reference Wind Turbine (RWT) model. The performance of the CRTEF...

  8. A smart rotor configuration with linear quadratic control of adaptive trailing edge flaps for active load alleviation

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Poulsen, Niels Kjølstad

    2015-01-01

    The paper proposes a smart rotor configuration where adaptive trailing edge flaps (ATEFs) are employed for active alleviation of the aerodynamic loads on the blades of the NREL 5 MW reference turbine. The flaps extend for 20% of the blade length and are controlled by a linear quadratic (LQ....... The effects of active flap control are assessed with aeroelastic simulations of the turbine in normal operation conditions, as prescribed by the International Electrotechnical Commission standard. The turbine lifetime fatigue damage equivalent loads provide a convenient summary of the results achieved...

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

    Science.gov (United States)

    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.

  10. Local correlations for flap gap oscillatory blowing active flow control technology

    Directory of Open Access Journals (Sweden)

    Cătălin NAE

    2010-09-01

    Full Text Available Active technology for oscillatory blowing in the flap gap has been tested at INCAS subsonic wind tunnel in order to evaluate this technology for usage in high lift systems with active flow control. The main goal for this investigation was to validate TRL level 4 for this technology and to extend towards flight testing. CFD analysis was performed in order to identify local correlations with experimental data and to better formulate a design criteria so that a maximum increase in lift is possible under given geometrical constraints. Reference to a proposed metric for noise evaluation is also given. This includes basic 2D flow cases and also 2.5D configurations. In 2.5D test cases this work has been extended so that the proposed system may be selected as a mature technology in the JTI Clean Sky, Smart Fixed Wing Aircraft ITD. Complex post-processing of the experimental and CFD data was mainly oriented towards system efficiency and TRL evaluation for this active technology.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zuteck, Michael D. [Zimitar, Inc.; Jackson, Kevin L. [Zimitar, Inc.; Santos, Richard A. [Zimitar, Inc.; Chow, Ray [Zimitar, Inc.; Nordenholz, Thomas R. [The California Maritime Academy; Wamble, John Lee [Zimitar, Inc.

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  15. Suspension Bridge Flutter for Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, T.; Thoft-Christensen, Palle

    Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...... on the Great Belt Bridge streamlined girder....

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

    Science.gov (United States)

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

    1994-06-01

    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.

  17. Identification of Flap Motion Parameters for Vibration Reduction in Helicopter Rotors with Multiple Active Trailing Edge Flaps

    Directory of Open Access Journals (Sweden)

    Uğbreve;ur Dalli

    2011-01-01

    Full Text Available An active control method utilizing the multiple trailing edge flap configuration for rotorcraft vibration suppression and blade loads control is presented. A comprehensive model for rotor blade with active trailing edge flaps is used to calculate the vibration characteristics, natural frequencies and mode shapes of any complex composite helicopter rotor blade. A computer program is developed to calculate the system response, rotor blade root forces and moments under aerodynamic forcing conditions. Rotor blade system response is calculated using the proposed solution method and the developed program depending on any structural and aerodynamic properties of rotor blades, structural properties of trailing edge flaps and properties of trailing edge flap actuator inputs. Rotor blade loads are determined first on a nominal rotor blade without multiple active trailing edge flaps and then the effects of the active flap motions on the existing rotor blade loads are investigated. Multiple active trailing edge flaps are controlled by using open loop controllers to identify the effects of the actuator signal output properties such as frequency, amplitude and phase on the system response. Effects of using multiple trailing edge flaps on controlling rotor blade vibrations are investigated and some design criteria are determined for the design of trailing edge flap controller that will provide actuator signal outputs to minimize the rotor blade root loads. It is calculated that using the developed active trailing edge rotor blade model, helicopter rotor blade vibrations can be reduced up to 36% of the nominal rotor blade vibrations.

  18. A flight control through unstable flapping flight

    Science.gov (United States)

    Iima, Makoto; Yokoyama, Naoto; Hirai, Norio; Senda, Kei

    2012-11-01

    We have studied a flight control in a two-dimensional flapping flight model for insects. In this model, the model of center-of-mass can move in both horizontal and vertical directions according to the hydrodynamic force generated by flapping. Under steady flapping, the model converges to steady flight states depending on initial conditions. We demonstrate that simple changes in flapping motion, a finite-time stop of flapping, results in changes in the vortex structures, and the separation of two steady flight state by a quasi-steady flight. The model's flight finally converges to one of the final states by way of the quasi-steady state, which is not observed as a (stable) steady flight. The flight dynamic has been also analyzed. KAKENHI (23540433, 22360105, 21340019) and CREST No. PJ74100011.

  19. Active flap control on an aeroelastic wind turbine airfoil in gust conditions using both a CFD and an engineering model

    Science.gov (United States)

    Gillebaart, T.; Bernhammer, L. O.; van Zuijlen, A. H.; van Kuik, G. A. M.

    2014-06-01

    In the past year, smart rotor technology has been studied significantly as solution to the ever growing turbines. Aeroservoelastic tools are used to asses and predict the behavior of rotors using trailing edge devices like flaps. In this paper an unsteady aerodynamic model (Beddoes-Leishman type) and an CFD model (URANS) are used to analyze the aeroservoelastic response of a 2D three degree of freedom rigid body wind turbine airfoil with a deforming trailing edge flap encountering deterministic gusts. Both uncontrolled and controlled simulations are used to asses the differences between the two models for 2D aerservoelastic simulations. Results show an increase in the difference between models for the y component if the deforming trailing edge flap is used as control device. Observed flap deflections are significantly larger in the URANS model in certain cases, while the same controller is used. The pitch angle and moment shows large differences in the uncontrolled case, which become smaller, but remain significant when the controller is applied. Both models show similar reductions in vertical displacement, with a penalty of a significant increase in pitch angle deflections.

  20. Wind Tunnel Test of the SMART Active Flap Rotor

    Science.gov (United States)

    Straub, Friedrich K.; Anand, Vaidyanthan R.; Birchette, Terrence S.; Lau, Benton H.

    2009-01-01

    Boeing and a team from Air Force, NASA, Army, DARPA, MIT, UCLA, and U. of Maryland have successfully completed a wind-tunnel test of the smart material actuated rotor technology (SMART) rotor in the 40- by 80-foot wind-tunnel of the National Full-Scale Aerodynamic Complex at NASA Ames Research Center. The Boeing SMART rotor is a full-scale, five-bladed bearingless MD 900 helicopter rotor modified with a piezoelectric-actuated trailing edge flap on each blade. The eleven-week test program evaluated the forward flight characteristics of the active-flap rotor at speeds up to 155 knots, gathered data to validate state-of-the-art codes for rotor aero-acoustic analysis, and quantified the effects of open and closed loop active flap control on rotor loads, noise, and performance. The test demonstrated on-blade smart material control of flaps on a full-scale rotor for the first time in a wind tunnel. The effectiveness of the active flap control on noise and vibration was conclusively demonstrated. Results showed significant reductions up to 6dB in blade-vortex-interaction and in-plane noise, as well as reductions in vibratory hub loads up to 80%. Trailing-edge flap deflections were controlled within 0.1 degrees of the commanded value. The impact of the active flap on control power, rotor smoothing, and performance was also demonstrated. Finally, the reliability of the flap actuation system was successfully proven in more than 60 hours of wind-tunnel testing.

  1. Magnetostrictively actuated control flaps for vibration reduction in helicopter rotors

    Energy Technology Data Exchange (ETDEWEB)

    Millott, T.; Friedmann, P.P. [Univ. of California, Los Angeles, CA (United States). Mechanical, Aerospace and Nuclear Engineering Dept.

    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.

  2. Smart dynamic rotor control using active flaps on a small-scale wind turbine: aeroelastic modeling and comparison with wind tunnel measurements

    DEFF Research Database (Denmark)

    Barlas, Thanasis K.; van Wingerden, W.; Hulskamp, A.W.

    2013-01-01

    In this paper, the proof of concept of a smart rotor is illustrated by aeroelastic simulations on a small-scale rotor and comparison with wind tunnel experiments. The application of advanced feedback controllers using actively deformed flaps in the wind tunnel measurements is shown to alleviate...... dynamic loads leading to considerable fatigue load reduction. The numerical method for aeroelastically simulating such an experiment is described, together with the process of verifying the methods for accurate prediction of the load reduction potential of such concepts. The small-scale rotor is simulated...... using the aeroelastic tool, load predictions are compared with the wind tunnel measurements, and similar control concepts are compared and evaluated in the numerical environment. Conclusions regarding evaluation of the performance of smart rotor concepts for wind turbines are drawn from this threefold...

  3. Design, manufacturing and testing of Controllable Rubber Trailing Edge Flaps

    DEFF Research Database (Denmark)

    Løgstrup Andersen, Tom; Aagaard Madsen, Helge; Barlas, Thanasis K

    The overall goal for the INDUFLAP project was realization of a test facility for development and test of Controllable Rubber Trailing Edge Flaps (CRTEF) for wind turbines. This report covers experimental work at DTU Wind Energy including design, manufacture and test of different configurations...... of flaps with voids in chord- or spanwise direction. Development of rubber flaps has involved further design improvements. Non-metallic spring elements and solutions for sealing of continuous extruded rubber profiles have been investigated....

  4. Comprehensive aeroelastic analysis of helicopter rotor with trailing-edge flap for primary control and vibration control

    Science.gov (United States)

    Shen, Jinwei

    , torsional frequency, flap location, flap length, and overhang length. The swashplateless rotor is shown to achieve better rotor performance and overall more stable than the conventional configuration. Simulations of flaps performing both primary control and active vibration control are carried out, with the conclusion that trailing-edge flaps are capable of trimming the rotor and simultaneously minimizing vibratory rotor hub loads.

  5. The PELskin project-part V: towards the control of the flow around aerofoils at high angle of attack using a self-activated deployable flap.

    Science.gov (United States)

    Rosti, Marco E; Kamps, Laura; Bruecker, Christoph; Omidyeganeh, Mohammad; Pinelli, Alfredo

    2017-01-01

    During the flight of birds, it is often possible to notice that some of the primaries and covert feathers on the upper side of the wing pop-up under critical flight conditions, such as the landing approach or when stalking their prey (see Fig. 1) . It is often conjectured that the feathers pop up plays an aerodynamic role by limiting the spread of flow separation . A combined experimental and numerical study was conducted to shed some light on the physical mechanism determining the feathers self actuation and their effective role in controlling the flow field in nominally stalled conditions. In particular, we have considered a NACA0020 aerofoil, equipped with a flexible flap at low chord Reynolds numbers. A parametric study has been conducted on the effects of the length, natural frequency, and position of the flap. A configuration with a single flap hinged on the suction side at 70 % of the chord size c (from the leading edge), with a length of [Formula: see text] matching the shedding frequency of vortices at stall condition has been found to be optimum in delivering maximum aerodynamic efficiency and lift gains. Flow evolution both during a ramp-up motion (incidence angle from [Formula: see text] to [Formula: see text] with a reduced frequency of [Formula: see text], [Formula: see text] being the free stream velocity magnitude), and at a static stalled condition ([Formula: see text]) were analysed with and without the flap. A significant increase of the mean lift after a ramp-up manoeuvre is observed in presence of the flap. Stall dynamics (i.e., lift overshoot and oscillations) are altered and the simulations reveal a periodic re-generation cycle composed of a leading edge vortex that lift the flap during his passage, and an ejection generated by the relaxing of the flap in its equilibrium position. The flap movement in turns avoid the interaction between leading and trailing edge vortices when lift up and push the trailing edge vortex downstream when

  6. Design and construction of an airfoil with controlled flap

    Science.gov (United States)

    Amin, Md. Ruhul; Rahman, S. M. Mahbobur; Mashud, Mohammad; Rabbi, Md. Fazle

    2017-06-01

    For modern aircrafts maneuvering control and reduction of power loss is a matter of great concern in Aerodynamics. Separation of airflow over the wings of aircraft at high angle of attack or at other situations is a hindrance to proper maneuvering control. As flow separation increases drag force on the aircraft, it consumes excess power. For these reasons much effort and research has gone into the design of aerodynamic surfaces which delay flow separation and keep the local flow attached for as long as possible. One of the simple and cost-effective way is to use a hinged flap on the wing of the aircraft, which lifts and self-adjusts to a position dependent on the aerodynamic forces and flap weight due to reversed flow at increasing angle of attack. There is a limitation of this kind of process. At very high angles of attack, the reversed flow would cause the flap to tip forwards entirely and the effect of the flap would vanish. For recovering this limitation an idea of controlling the movement or rotation of the flap has been proposed in this paper. A light surface was selected as a flap and was coupled to the shaft of a servo motor, which was placed on a model airfoil. For controlling the angle of rotation of the motor as well as the flap arbitrarily, an electronic circuit comprising necessary components was designed and applied to the servo motor successfully.

  7. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

  8. Unsteady aerodynamics and flow control for flapping wing flyers

    Science.gov (United States)

    Ho, Steven; Nassef, Hany; Pornsinsirirak, Nick; Tai, Yu-Chong; Ho, Chih-Ming

    2003-11-01

    The creation of micro air vehicles (MAVs) of the same general sizes and weight as natural fliers has spawned renewed interest in flapping wing flight. With a wingspan of approximately 15 cm and a flight speed of a few meters per second, MAVs experience the same low Reynolds number (10 4-10 5) flight conditions as their biological counterparts. In this flow regime, rigid fixed wings drop dramatically in aerodynamic performance while flexible flapping wings gain efficacy and are the preferred propulsion method for small natural fliers. Researchers have long realized that steady-state aerodynamics does not properly capture the physical phenomena or forces present in flapping flight at this scale. Hence, unsteady flow mechanisms must dominate this regime. Furthermore, due to the low flight speeds, any disturbance such as gusts or wind will dramatically change the aerodynamic conditions around the MAV. In response, a suitable feedback control system and actuation technology must be developed so that the wing can maintain its aerodynamic efficiency in this extremely dynamic situation; one where the unsteady separated flow field and wing structure are tightly coupled and interact nonlinearly. For instance, birds and bats control their flexible wings with muscle tissue to successfully deal with rapid changes in the flow environment. Drawing from their example, perhaps MAVs can use lightweight actuators in conjunction with adaptive feedback control to shape the wing and achieve active flow control. This article first reviews the scaling laws and unsteady flow regime constraining both biological and man-made fliers. Then a summary of vortex dominated unsteady aerodynamics follows. Next, aeroelastic coupling and its effect on lift and thrust are discussed. Afterwards, flow control strategies found in nature and devised by man to deal with separated flows are examined. Recent work is also presented in using microelectromechanical systems (MEMS) actuators and angular speed

  9. Development and whirl tower test of the SMART active flap rotor

    Science.gov (United States)

    Straub, Friedrich K.; Kennedy, Dennis K.; Stemple, Alan D.; Anand, V. R.; Birchette, Terry S.

    2004-07-01

    A full scale Smart Material Actuated Rotor Technology (SMART) system with piezoelectric actuated blade flaps was developed and whirl tower tested. The development effort included design, fabrication, and component testing of rotor blades, trailing edge flaps, piezoelectric actuators, switching power amplifiers, and the data/power system. Simulations and model scale wind tunnel tests have shown that this system can provide 80% vibration reduction, 10dB noise reduction for a helicopter passing overhead, and substantial aerodynamic performance gains. Whirl tower testing of the 34-foot diameter rotor demonstrated the functionality, robustness, and required authority of the active flap system. The program involved extensive development work and risk reduction tests which resulted in a robust, high performance actuator and a tightly integrated actuator, flap, and blade system. The actuator demonstrated excellent performance during bench testing and has accumulated over 60 million cycles under a spectrum of loading conditions. The flight worthy active flap rotor blades were based on a modified design of the FAA certified MD900 Explorer production rotor blade. Whirl tower testing was conducted with full rotor instrumentation and a 5-component balance. The rotor was tested for 13 hours under a range of conditions, including 7 hours of flap operation. Flap inputs included open loop static and dynamic commands. The flaps showed excellent authority with oscillatory thrust greater than 10% of the steady baseline thrust. Various flap actuation frequency sweeps were run to investigate the dynamics of the rotor and the flap system. Limited closed loop tests used hub accelerations and hub loads for feedback. Proving the integration, robust operation, and authority of the flap system were the key objectives met by the whirl tower test. This success depended on tailoring the piezoelectric materials and actuator to the application and meeting actuator/blade integration requirements

  10. Model Predictive Control of Trailing Edge Flaps on a wind turbine blade

    DEFF Research Database (Denmark)

    Castaignet, Damien; Poulsen, Niels Kjølstad; Buhl, Thomas

    2011-01-01

    Trailing Edge Flaps on wind turbine blades have been studied in order to achieve fatigue load reduction on the turbine components. We show in this paper how Model Predictive Control can be used to do frequency weighted control of the trailing edge flaps in order to reduce fatigue damage...... significantly the blade root loads without damaging excessively the trailing edge flap actuators....

  11. Simulations of a rotor with active deformable trailing edge flaps in half-wake inflow: Comparison of EllipSys 3D with HAWC2

    DEFF Research Database (Denmark)

    Barlas, Thanasis K.; Zahle, Frederik; Sørensen, Niels N.

    2012-01-01

    Various research projects have focused on active aerodynamic load control of wind turbines using control devices on the blades, for example flaps. The aerodynamic load predictions of utilized aeroelastic codes have not yet been fully validated with full rotor CFD or experimental results......-uniform inflow mimicking a half-wake situation, using different control methods and maximum flap angles. Three different control inputs are simulated: a prescribed flap angle based on the a priori knowledge of the inflow velocity, a controller based on the blade root flap-wise moment feedback, and finally...

  12. Adaptive Trailing Edge Flaps for Active Load Alleviation in a Smart Rotor Configuration

    DEFF Research Database (Denmark)

    Bergami, Leonardo

    capture below rated conditions by using the flaps. Two model based control algorithms are developed to actively alleviate the fatigue loads on the smart rotor with ATEF. The first algorithm features a linear quadratic regulator with periodic disturbance rejection, and controls the deflection of the flap......The work investigates the development of an active smart rotor concept from an aero-servo-elastic perspective. An active smart rotor is a wind turbine rotor that, through a combination of sensors, control units and actuators, is able to alleviate the fluctuating part of the aerodynamic loads it has...... the available actuators: ATEF, individual blade pitch, and generator. Both algorithms include frequency-dependent weighting of the control actions in order to limit high frequency control activity, and thus effectively reduce actuators use and wear. The smart rotor performances are evaluated from HAWC2...

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

    Science.gov (United States)

    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.

  14. Neuroinspired control strategies with applications to flapping flight

    Science.gov (United States)

    Dorothy, Michael Ray

    This dissertation is centered on a theoretical, simulation, and experimental study of control strategies which are inspired by biological systems. Biological systems, along with sufficiently complicated engineered systems, often have many interacting degrees of freedom and need to excite large-displacement oscillations in order to locomote. Combining these factors can make high-level control design difficult. This thesis revolves around three different levels of abstraction, providing tools for analysis and design. First, we consider central pattern generators (CPGs) to control flapping-flight dynamics. The key idea here is dimensional reduction - we want to convert complicated interactions of many degrees of freedom into a handful of parameters which have intuitive connections to the overall system behavior, leaving the control designer unconcerned with the details of particular motions. A rigorous mathematical and control theoretic framework to design complex three-dimensional wing motions is presented based on phase synchronization of nonlinear oscillators. In particular, we show that flapping-flying dynamics without a tail or traditional aerodynamic control surfaces can be effectively controlled by a reduced set of central pattern generator parameters that generate phase-synchronized or symmetry-breaking oscillatory motions of two main wings. Furthermore, by using a Hopf bifurcation, we show that tailless aircraft (inspired by bats) alternating between flapping and gliding can be effectively stabilized by smooth wing motions driven by the central pattern generator network. Results of numerical simulation with a full six-degree-of-freedom flight dynamic model validate the effectiveness of the proposed neurobiologically inspired control approach. Further, we present experimental micro aerial vehicle (MAV) research with low-frequency flapping and articulated wing gliding. The importance of phase difference control via an abstract mathematical model of central

  15. Full-scale test of trailing edge flaps on a Vestas V27 wind turbine: active load reduction and system identification

    DEFF Research Database (Denmark)

    Castaignet, Damien; Barlas, Thanasis K.; Buhl, Thomas

    2014-01-01

    model, from trailing edge flap angle to flapwise blade root moment, was derived and compared with the linear analytical model used in the model predictive control design model. Flex5 simulations run with the same model predictive control showed a good correlation between the simulations......A full-scale test was performed on a Vestas V27 wind turbine equipped with one active 70 cm long trailing edge flap on one of its 13 m long blades. Active load reduction could be observed in spite of the limited spanwise coverage of the single active trailing edge flap. A frequency-weighted model...

  16. Deformable trailing edge flaps for modern megawatt wind turbine controllers using strain gauge sensors

    DEFF Research Database (Denmark)

    Andersen, Peter Bjørn; Henriksen, Lars Christian; Gaunaa, Mac

    2010-01-01

    . By enabling the trailing edge to move independently and quickly along the spanwise position of the blade, local small flutuations in the aerodynamic forces can be alleviated by deformation of the airfoil flap. Strain gauges are used as input for the flap controller, and the effect of placing strain gauges......The present work contains a deformable trailing edge flap controller integrated in a numerically simulated modern, variablespeed, pitch-regulated megawatt (MW)-size wind turbine. The aeroservoelastic multi-body code HAWC2 acts as a component in the control loop design. At the core of the proposed...... edge flaps on a wind turbine blade rather than a conclusive control design with traditional issues like stability and robustness fully investigated. Recent works have shown that the fatigue load reduction by use of trailing edge flaps may be greater than for traditional pitch control methods...

  17. Adaptive trailing edge flaps for active load alleviation in a smart rotor configuration

    Energy Technology Data Exchange (ETDEWEB)

    Bergami, L.

    2013-08-15

    The work investigates the development of an active smart rotor concept from an aero-servo-elastic perspective. An active smart rotor is a wind turbine rotor that, through a combination of sensors, control units and actuators, is able to alleviate the fluctuating part of the aerodynamic loads it has to withstand. The investigation focuses on a specific actuator type: the Adaptive Trailing Edge Flap (ATEF), which introduces a continuous deformation of the aft part of the airfoil camber-line. An aerodynamic model that accounts for the steady and unsteady effects of the flap deflection on a 2D airfoil section is developed, and, considering both attached and separated flow conditions, is validated by comparison against Computational Fluid Dynamic solutions and a panel code method. The aerodynamic model is integrated in the BEM-based aeroelastic simulation code HAWC2, thus providing a tool able to simulate the response of a wind turbine equipped with ATEF. A load analysis of the NREL 5 MW reference turbine in its baseline configuration reveals that the highest contribution to the blade flapwise fatigue damage originates from normal operation above rated wind speed, and from loads characterized by frequencies below 1 Hz. The analysis also reports that periodic load variations on the turbine blade account for nearly 11 % of the blade flapwise lifetime fatigue damage, while the rest is ascribed to load variations from disturbances of stochastic nature. The study proposes a smart rotor configuration with flaps laid out on the outer 20 % of the blade span, from 77 % to 97% of the blade length. The configuration is first tested with a simplified cyclic control approach, which gives a preliminary indication of the load alleviation potential, and also reveals the possibility to enhance the rotor energy capture below rated conditions by using the flaps. Two model based control algorithms are developed to actively alleviate the fatigue loads on the smart rotor with ATEF. The first

  18. Structural and mechanism design of an active trailing-edge flap blade

    DEFF Research Database (Denmark)

    Lee, Jae Hwan; Natarajan, Balakumaran; Eun, Won Jong

    2013-01-01

    , as the blade is able to withstand increased centrifugal force. The cross-section of the active blade is designed first. A stress/strain recovery analysis is then conducted to verify its structural integrity. A one-dimensional beam analysis is also carried out to assist with the construction of the fan diagram....... To select the actuator and design the flap actuation region, the flap hinge moment is estimated via a CFD analysis. To obtain the desired flap deflection of ±4°, three actuators are required. The design of the flap actuation region is validated using a test bed with a skin hinge. However, because the skin...... hinge induces additional flap hinge moment, it does not provide sufficient deflection angle. Therefore, the flap hinge is replaced by a pin-type hinge, and the results are evaluated....

  19. Load alleviation potential of the Controllable Rubber Trailing Edge Flap (CRTEF) in the INDUFLAP project

    DEFF Research Database (Denmark)

    Barlas, Thanasis K.; Bergami, Leonardo; Hansen, Morten Hartvig

    The load alleviation potential of the Controllable Rubber Trailing Edge Flap (CRTEF) is verified on a full Design Load Base (DLB) setup using the aeroelastic code HAWC2, and by investigating a flap configuration for the NREL 5MW Reference Wind Turbine (RWT) model. The performance of the CRTEF...

  20. Primary control of a Mach scale swashplateless rotor using brushless DC motor actuated trailing edge flaps

    Science.gov (United States)

    Saxena, Anand

    The focus of this research was to demonstrate a four blade rotor trim in forward flight using integrated trailing edge flaps instead of using a swashplate controls. A compact brushless DC motor was evaluated as an on-blade actuator, with the possibility of achieving large trailing edge flap amplitudes. A control strategy to actuate the trailing edge flap at desired frequency and amplitude was developed and large trailing edge flap amplitudes from the motor (instead of rotational motion) were obtained. Once the actuator was tested on the bench-top, a lightweight mechanism was designed to incorporate the motor in the blade and actuate the trailing edge flaps. A six feet diameter, four bladed composite rotor with motor-flap system integrated into the NACA 0012 airfoil section was fabricated. Systematic testing was carried out for a range of load conditions, first in the vacuum chamber followed by hover tests. Large trailing edge flap deflections were observed during the hover testing, and a peak to peak trailing edge flap amplitude of 18 degree was achieved at 2000 rotor RPM with hover tip Mach number of 0.628. A closed loop controller was designed to demonstrate trailing edge flap mean position and the peak to peak amplitude control. Further, a soft pitch link was designed and fabricated, to replace the stiff pitch link and thereby reduce the torsional stiffness of the blade to 2/rev. This soft pitch link allowed for blade root pitch motion in response to the trailing edge flap inputs. Blade pitch response due to both steady as well as sinusoidal flap deflections were demonstrated. Finally, tests were performed in Glenn L. Martin wind tunnel using a model rotor rig to assess the performance of motor-flap system in forward flight. A swashplateless trim using brushless DC motor actuated trailing edge flaps was achieved for a rotor operating at 1200 RPM and an advance ratio of 0.28. Also, preliminary exploration was carried out to test the scalability of the motor

  1. Flap/Lag Stall Flutter Control of Large-Scale Wind Turbine Blade Based on Robust H2 Controller

    Directory of Open Access Journals (Sweden)

    Tingrui Liu

    2016-01-01

    Full Text Available Flap/lag stall nonlinear flutter and active control of anisotropic composite wind turbine blade modeled as antisymmetric beam analysis have been investigated based on robust H2 controller. The blade is modeled as single-cell thin-walled beam structure, exhibiting flap bending moment-lag transverse shear deformation, and lag bending moment-flap transverse shear deformation, with constant pitch angle set. The stall flutter control of dynamic response characteristics of composite blade incorporating nonlinear aerodynamic model is investigated based on some structural and dynamic parameters. The aeroelastic partial differential equations are reduced by Galerkin method, with the aerodynamic forces decomposed by strip theory. Robust H2 optimal controller is developed to enhance the vibrational behavior and dynamic response to aerodynamic excitation under extreme wind conditions and stabilize structures that might be damaged in the absence of control. The effectiveness of the control algorithm is demonstrated in both amplitudes and frequencies by description of time responses, extended phase planes, and frequency spectrum analysis, respectively.

  2. A Model Based Control methodology combining Blade Pitch and Adaptive Trailing Edge Flaps in a common framework

    DEFF Research Database (Denmark)

    This work investigates how adaptive trailing edge flaps and classical blade pitch can work in concert using a model-based state space control formulation. The trade-off between load reduction and actuator activity is decided by setting different weights in the objective function used by the model...

  3. A Model Based Control methodology combining Blade Pitch and Adaptive Trailing Edge Flaps in a common framework

    DEFF Research Database (Denmark)

    Henriksen, Lars Christian; Bergami, Leonardo; Andersen, Peter Bjørn

    2013-01-01

    This work investigates how adaptive trailing edge flaps and classical blade pitch can work in concert using a model-based state space control formulation. The trade-off between load reduction and actuator activity is decided by setting different weights in the objective function used by the model...

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

    Science.gov (United States)

    Deering, Kenneth J [Seattle, WA; Wohlwend, Keith P [Issaquah, WA

    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.

  5. Computational Investigations of Small Deploying Tabs and Flaps for Aerodynamic Load Control

    Energy Technology Data Exchange (ETDEWEB)

    Dam, C P van [Mechanical and Aeronautical Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Chow, R [Mechanical and Aeronautical Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Zayas, J R [Wind Energy Technology Department, Sandia National Laboratories, PO Box 5800, MS 1124, Albuquerque, NM 87185-1124 (United States); Berg, D E [Wind Energy Technology Department, Sandia National Laboratories, PO Box 5800, MS 1124, Albuquerque, NM 87185-1124 (United States)

    2007-07-15

    The cost of wind-generated electricity can be reduced by mitigating fatigue loads acting on the blades of wind turbine rotors. One way to accomplish this is with active aerodynamic load control devices that supplement the load control obtainable with current full-span pitch control. Techniques to actively mitigate blade loads that are being considered include individual blade pitch control, trailing-edge flaps, and other much smaller trailing-edge devices such as microtabs and microflaps. The focus of this paper is on the latter aerodynamic devices, their time-dependent effect on sectional lift, drag, and pitching moment, and their effectiveness in mitigating high frequency loads on the wind turbine. Although these small devices show promise for this application, significant challenges must be overcome before they can be demonstrated to be a viable, cost-effective technology.

  6. Computational Investigations of Small Deploying Tabs and Flaps for Aerodynamic Load Control

    Science.gov (United States)

    van Dam, C. P.; Chow, R.; Zayas, J. R.; Berg, D. E.

    2007-07-01

    The cost of wind-generated electricity can be reduced by mitigating fatigue loads acting on the blades of wind turbine rotors. One way to accomplish this is with active aerodynamic load control devices that supplement the load control obtainable with current full-span pitch control. Techniques to actively mitigate blade loads that are being considered include individual blade pitch control, trailing-edge flaps, and other much smaller trailing-edge devices such as microtabs and microflaps. The focus of this paper is on the latter aerodynamic devices, their time-dependent effect on sectional lift, drag, and pitching moment, and their effectiveness in mitigating high frequency loads on the wind turbine. Although these small devices show promise for this application, significant challenges must be overcome before they can be demonstrated to be a viable, cost-effective technology.

  7. A Roll Controlling Approach for a Simple Dual-Actuated Flapping Aerial Vehicle Model

    Directory of Open Access Journals (Sweden)

    Labib Omar El-Farouk E.

    2016-01-01

    Full Text Available Aerial vehicles have been investigated recently in different contexts, due to their high potential of utilization in multiple application areas. Different mechanisms can be used for aerial vehicles actuation, such as the rotating multi-blade systems (Multi-Copters and more recently flapping wings. Flapping wing robots have attracted much attention from researchers in recent years. In this study, a simple dual-actuated flapping mechanism is proposed for actuating a flapping wing robot. The mechanism is designed, simulated and validated in both simulation and experiments. A roll controlling approach is proposed to control the roll angle of the robot via controlling the speeds of both motors actuating each of the wings. The results achieved are validated experimentally, and are promising opening the door for further investigation using our proposed system

  8. Flap preconditioning by pressure-controlled cupping in a rat model.

    Science.gov (United States)

    Koh, Kyung S; Park, Sung Woo; Oh, Tae Suk; Choi, Jong Woo

    2016-08-01

    Flap survival is essential for the success of soft-tissue reconstruction. Accordingly, various surgical and medical methods aim to increase flap survival. Because flap survival is affected by the innate vascular supply, traditional preconditioning methods mainly target vasodilatation or vascular reorientation to increase blood flow to the tissue. External stress on the skin, such as an external volume expander or cupping, induces vascular remodeling, and these approaches have been used in the fat grafting field and in traditional Asian medicine. In the present study, we used a rat random-pattern dorsal flap model to study the effectiveness of preconditioning with an externally applied device (cupping) at the flap site that directly applied negative pressure to the skin. The device, the pressure-controlled cupping, is connected to negative pressure vacuum device providing accurate pressure control from 0 mm Hg to -200 mm Hg. Flap surgery was performed after preconditioning under -25 mm Hg suction pressure for 30 min a day for 5 d, followed by 9 d of postoperative observation. Flap survival was assessed as the area of viable tissue and was compared between the preconditioned group and a control group. The preconditioned group showed absolute percentage increase of flap viability relative to the entire flap by 19.0± 7.6% (average 70.1% versus 51.0%). Tissue perfusion of entire flap, evaluated by laser Doppler imaging system, was improved with absolute percentage increase by 24.2± 10.4% (average 77.4% versus 53.1%). Histologic analysis of hematoxylin and eosin, CD31, and Masson-trichrome staining showed increased vascular density in the subdermal plexus and more organized collagen production with hypertrophy of the attached muscle. Our study suggests that flap preconditioning caused by controlled noninvasive suction induces vascular remodeling that increases tissue perfusion and improves flap survival in a rat model. Copyright © 2016 Elsevier Inc. All rights

  9. Wind tunnel tests with combined pitch and free-floating flap control: data-driven iterative feedforward controller tuning

    National Research Council Canada - National Science Library

    Sachin T Navalkar; Lars O Bernhammer; Jurij Sodja; Edwin van Solingen; Gijs A M van Kuik; Jan-Willem van Wingerden

    2016-01-01

      Wind turbine load alleviation has traditionally been addressed in the literature using either full-span pitch control, which has limited bandwidth, or trailing-edge flap control, which typically...

  10. Performance of Swashplateless Ultralight Helicopter Rotor with Trailing-edge Flaps for Primary Flight Control

    Science.gov (United States)

    Shen, Jin-Wei; Chopra, Inderjit

    2003-01-01

    The objective of present study is to evaluate the rotor performance, trailing-edge deflections and actuation requirement of a helicopter rotor with trailing-edge flap system for primary flight control. The swashplateless design is implemented by modifying a two-bladed teetering rotor of an production ultralight helicopter through the use of plain flaps on the blades, and by replacing the pitch link to fixed system control system assembly with a root spring. A comprehensive rotorcraft analysis based on UMARC is carried out to obtain the results for both the swashplateless and a conventional baseline rotor configuration. The predictions show swashplateless configuration achieve superior performance than the conventional rotor attributed from reduction of parasite drag by eliminating swashplate mechanic system. It is indicated that optimal selection of blade pitch index angle, flap location, length, and chord ratio reduces flap deflections and actuation requirements, however, has virtually no effect on rotor performance.

  11. Flap-lag-torsion aeroelastic stability of circulation-controlled rotors in hover

    Science.gov (United States)

    Chopra, I.; Johnson, W.

    1978-01-01

    The results of a theoretical investigation of the flap-lag-torsion stability of circulation controlled rotors in hover are presented. Stability boundaries are presented as a function of thrust and lag frequency, at several levels of blowing coefficient, for flap frequencies of 1.1/rev and 1.8/ rev. The effects of several parameters on the blade flap-lag stability are examined, including structural damping, structural coupling, pitch-lag and pitch-flap coupling, and the blade feathering motion. The trailing edge blowing can have a major impact on the blade aeroelastic stability, which should be considered in the rotor design. The implications of these results for the current CCR and X-Wing rotorcraft designs are considered.

  12. Buffeting Response of Suspension Bridge Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, Truc; Thoft-Christensen, Palle

    is of interest. The RMS response is determined on the basis of the equation of motion, which is formulated stochastically according to the wind random turbulence components. It is further assumed that the sum of the motion-induced forces and the buffeting-induced forces from the girder and the flaps is computed...

  13. Wind Tunnel Experiments with Active Control of Bridge Section Model

    DEFF Research Database (Denmark)

    Hansen, Henriette I.; Thoft-Christensen, Palle

    This paper describes results of wind tunnel experiments with a bridge section model where movable flaps are integrated in the bridge girder so each flap is the streamlined part of the edge of the girder. This active control flap system is patented by COWIconsult and may be used to increase...... the flutter wind velocity for future ultra-long span suspension bridges. The purpose of the wind tunnel experiments is to investigate the principle to use this active flap control system. The bridge section model used in the experiments is therefore not a model of a specific bridge but it is realistic...

  14. Flap controllers applied on the OffshoreWindChina (OWC) 5MW reference wind turbine for Chinese typhoon conditions

    DEFF Research Database (Denmark)

    Barlas, Athanasios

    The report describes the development of flap controllers applied on the OffshoreWindChina (OWC) 5MW reference wind turbine for Chinese typhoon conditions. Optimal flap controllers are designed and tuned based on linear aeroelastic models from HawcStab2. The controllers are evaluated in normal......, parked and storm conditions, targeting the alleviation of fatigue and extreme loads....

  15. Closed loop control of a flap exposed to harmonic aerodynamic actuation

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Mikkelsen, Robert Flemming; Sørensen, Jens Nørkær

    2012-01-01

    Wind tunnel testing of a two-dimensional aerofoil with a load reducing flap has been conducted under the influence of a closed-loop controller (PID). Upstream synthetic perturbations for well-defined testing of the controller were generated by instrumenting the wind tunnel with two fast turning...

  16. Investigation of the maximum load alleviation potential using trailing edge flaps controlled by inflow data

    DEFF Research Database (Denmark)

    Fischer, Andreas; Aagaard Madsen, Helge

    2014-01-01

    The maximum fatigue load reduction potential when using trailing edge flaps on mega-watt wind turbines was explored. For this purpose an ideal feed forward control algorithm using the relative velocity and angle of attack at the blade to control the loads was implemented. The algorithm was applied...

  17. Active load reduction by means of trailing edge flaps on a wind turbine blade

    DEFF Research Database (Denmark)

    Couchman, Ian; Castaignet, Damien; Poulsen, Niels Kjølstad

    2014-01-01

    This paper presents the blade fatigue load reduction achieved with a trailing edge flap during a full scale test on a Vestas V27 wind turbine. A frequency-weighted linear model predictive control (MPC) is tuned to decrease flapwise blade root fatigue loads at the frequencies where most of the blade...... damage occurs, i.e. the 1P and 2P frequencies (respectively 1 and 2 events per revolution). Frequency-weighted MPC is chosen for its ability to handle constraints on the trailing edge flap deflection and to optimise its actuation in order to decrease wear and tear of the actuator. The controller...

  18. Visualization of flow separation and control by vortex generators on an single flap in landing configuration

    Directory of Open Access Journals (Sweden)

    Matějka Milan

    2012-04-01

    Full Text Available This paper focuses on a suppression of the flow separation, which occurs on a deflected flap, by means of vortex generators (VG's. An airfoil NACA 63A421 with a simple flap and vane-type vortex generators were used. The investigation was carried out by using experimental and numerical methods. The data from the numerical simulation of the flapped airfoil without VG's control were used for the vortex generator design. Two sizes, two different shapes and various spacing of the vortex generators were tested. The flow past the airfoil was visualized through three methods, namely tuft filaments technique, oil and thermo camera visualization. The experiments were performed in closed circuit wind tunnels with closed and open test sections. The lift curves for both cases without and with vortex generators were acquired for a lift coefficient improvement determination. The improvement was achieved for several cases by means all of the applied methods.

  19. Material matters: Controllable rubber trailing edge flap regulates load on wind turbine blades

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge

    2010-01-01

    In wind farms, nearby wind turbines exert considerable influence and generate turbulence on turbine blades. Because the blades are so long, there can be considerable differences in localized loading from the gusts along the blade. The Risø DTU researchers has developed a controllable rubber...... trailing edge flap, known as CRTEF. The trailing edge blade design is expected to help mitigate localized loading, and its molded rubber design, the sharp trailing edge, produces less noise and greater output. With CRTEF, the blade automatically has a completely sharp edge. The elastic flap tested...

  20. Kinematic control of aerodynamic forces on an inclined flapping wing with asymmetric strokes.

    Science.gov (United States)

    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

  1. Investigation of the theoretical load alleviation potential using trailing edge flaps controlled by inflow data

    DEFF Research Database (Denmark)

    Fischer, Andreas; Aagaard Madsen, Helge

    2016-01-01

    A novel control concept for fatigue load reduction with trailing edge flaps based on the measurement of the inflow locally on the blade was presented. The investigation was conducted with the aeroelastic code HAWC2. The aerodynamic modelling in the code is based on blade element momentum theory...... effects seem to be negligible. Copyright © 2015 John Wiley & Sons, Ltd....

  2. Effects of nitroglycerin ointment on mastectomy flap necrosis in immediate breast reconstruction: a randomized controlled trial.

    Science.gov (United States)

    Gdalevitch, Perry; Van Laeken, Nancy; Bahng, Seokjae; Ho, Adelyn; Bovill, Esta; Lennox, Peter; Brasher, Penelope; Macadam, Sheina

    2015-06-01

    Mastectomy flap necrosis is a common complication of immediate breast reconstruction that impacts recovery time and reconstructive success. Nitroglycerin ointment is a topical vasodilator that has been shown to improve skin flap survival in an animal model. The objective of this study was to evaluate whether the application of nitroglycerin ointment to the breast skin after mastectomy and immediate reconstruction causes a decrease in the rate of mastectomy flap necrosis compared with placebo. This study was conducted as a randomized controlled trial and included patients aged 21 to 69 years undergoing mastectomy and immediate breast reconstruction at the University of British Columbia-affiliated hospitals (Vancouver, British Columbia, Canada). Patients with a medical history that precluded the administration of nitroglycerin were excluded from the study. The target sample size was 400 patients. Nitroglycerin ointment (45 mg) or a placebo was applied to the mastectomy skin at the time of surgical dressing. The trial was stopped at the first interim analysis after 165 patients had been randomized (85 to the treatment group and 80 to the placebo group). Mastectomy flap necrosis developed in 27 patients (33.8 percent) receiving placebo and in 13 patients (15.3 percent) receiving nitroglycerin ointment; the between-group difference was 18.5 percent (p = 0.006; 95 percent CI, 5.3 to 31.0 percent). Postoperative complications were similar in both groups [nitroglycerin, 22.4 percent (19 of 85); placebo, 28.8 percent (23 of 80)]. In patients undergoing mastectomy and immediate reconstruction, there was a marked reduction in mastectomy flap necrosis in patients who received nitroglycerin ointment. Nitroglycerin ointment application is a simple, safe, and effective way to help prevent mastectomy flap necrosis. Therapeutic, I.

  3. Wind tunnel tests with combined pitch and free-floating flap control: data-driven iterative feedforward controller tuning

    NARCIS (Netherlands)

    Navalkar, S.T.; Bernhammer, L.O.; Sodja, J.; van Solingen, E.; van Kuik, G.A.M.; van Wingerden, J.W.

    2016-01-01

    Wind turbine load alleviation has traditionally been addressed in the literature using either full-span pitch control, which has limited bandwidth, or trailing-edge flap control, which typically shows low control authority due to actuation constraints. This paper combines both methods and

  4. Multidisciplinary CFD/CSD Analysis of the Smart Active Flap Rotor

    Science.gov (United States)

    2010-05-01

    plus 5 beam elements for the flexbeam. Baseline structural properties were used for the flexbeam, pitchcase, and blade. The hub and swashplate are...produces forces equivalent to swashplate collective and cyclic pitch. Figure 14 shows CFD/CSD predicted control power for both 0P flap input and collective

  5. Wind tunnel testing of a full scale helicopter blade section with an upstream active Gurney flap

    NARCIS (Netherlands)

    Loendersloot, Richard; Freire Gomez, J.; Booker, J.D.

    2014-01-01

    Wind tunnel tests were performed on an aerofoil section comparable to that of a full scale helicopter blade section with an upstream active Gurney flap in the framework of the European project CleanSky ITD Green RotorCraft. A modified NACA0012 profile was used, with 23 Kulite pressure transducers

  6. Aeroelastic Optimization of a 10 MW Wind Turbine Blade with Active Trailing Edge Flaps

    DEFF Research Database (Denmark)

    Barlas, Athanasios; Tibaldi, Carlo; Zahle, Frederik

    2016-01-01

    This article presents the aeroelastic optimization of a 10MW wind turbine ‘smart blade’ equipped with active trailing edge flaps. The multi-disciplinary wind turbine analysis and optimization tool HawtOpt2 is utilized, which is based on the open-source framework Open-MDAO. The tool interfaces to ...

  7. Variable Camber Continuous Aerodynamic Control Surfaces and Methods for Active Wing Shaping Control

    Science.gov (United States)

    Nguyen, Nhan T. (Inventor)

    2016-01-01

    An aerodynamic control apparatus for an air vehicle improves various aerodynamic performance metrics by employing multiple spanwise flap segments that jointly form a continuous or a piecewise continuous trailing edge to minimize drag induced by lift or vortices. At least one of the multiple spanwise flap segments includes a variable camber flap subsystem having multiple chordwise flap segments that may be independently actuated. Some embodiments also employ a continuous leading edge slat system that includes multiple spanwise slat segments, each of which has one or more chordwise slat segment. A method and an apparatus for implementing active control of a wing shape are also described and include the determination of desired lift distribution to determine the improved aerodynamic deflection of the wings. Flap deflections are determined and control signals are generated to actively control the wing shape to approximate the desired deflection.

  8. Bio-Inspired Integrated Sensing and Control Flapping Flight for Micro Aerial Vehicles

    Science.gov (United States)

    2012-02-28

    experimentation of engineered flapping flight. A robotic bat with 8 motors has been developed and installed on a 3-DOF pendulum [B1]. This AFOSR project...metric which is based entirely on a steady maneuver [61]. It is also an important benchmark to evaluate the efficacy of a yaw control mechanism. 3.2...capability of the wings. The foam table on which the aircraft is resting is not part of the airframe. modified version of the commerically

  9. Roles of coactosin-like protein (CLP) and 5-lipoxygenase-activating protein (FLAP) in cellular leukotriene biosynthesis.

    Science.gov (United States)

    Basavarajappa, Devaraj; Wan, Min; Lukic, Ana; Steinhilber, Dieter; Samuelsson, Bengt; Rådmark, Olof

    2014-08-05

    5-Lipoxygenase (5LO) is a key enzyme in leukotriene (LT) biosynthesis. Two accessory proteins, coactosin-like protein (CLP) and 5-lipoxygenase-activating protein (FLAP), can support 5LO activity. To study the roles of CLP and FLAP, we knocked down these proteins in the human monocytic cell line Mono Mac 6 (MM6). Expression of CLP increased MM6 cellular 5LO activity for all stimuli tested. CLP is not absolutely crucial, however; some 5LO activity remained in all incubations of CLP knockdown cells. FLAP knockdown had minor effects in the presence of exogenous arachidonic acid, but led to prominent reductions in 5LO product formation from endogenous substrate. Similar effects were observed after CLP and FLAP knockdown in human primary macrophages as well. In addition, FLAP knockdown reduced conversion of leukotriene A4 to leukotriene C4 (LTC4), suggesting a role for the activity of LTC4 synthase. After stimulation of MM6 cells by phorbol myristate acetate and ionophore A23187, a perinuclear ring pattern was observed for 5LO. This redistribution from cytosolic to perinuclear was clearly compromised in both CLP- and FLAP-deficient cells. In addition, association of CLP with the nucleus was almost absent after 5LO knockdown, and was clearly reduced in FLAP knockdown cells. Coimmunoprecipitation experiments indicated that 5LO-CLP complex formation in MM6 cells was increased by stimulation with ionophore, and that this complex was formed to the same extent in FLAP knockdown cells. A possible interpretation of our findings is that on cell stimulation, formation of the 5LO-CLP complex augments the translocation from cytosol to nucleus, whereas FLAP stabilizes association of this complex with the perinuclear membrane.

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

    Science.gov (United States)

    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

  11. Investigation of the load reduction potential of two trailing edge flap controls using CFD

    DEFF Research Database (Denmark)

    Heinz, Joachim Christian; Sørensen, Niels N.; Zahle, Frederik

    2011-01-01

    In this work, a 2D aero‐servo‐elastic model of an airfoil section with 3 degrees of freedom (DOF) based on the 2D CFD solver EllipSys2D to calculate the aerodynamic forces is utilized to calculate the load reduction potential of an airfoil equipped with an adaptive trailing edge flap (ATEF...... normal forces on the airfoil due to a 4 s turbulent inflow signal and the best location of the measurement point for the respective control input is determined. While Control 1 uses the measurements of a Pitot tube mounted in front of the leading edge (LE) as input, Control 2 uses the pressure difference...

  12. 2D CFD Analysis of an Airfoil with Active Continuous Trailing Edge Flap

    Science.gov (United States)

    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.

  13. Swashplateless Helicopter Experimental Investigation: Primary Control with Trailing Edge Flaps Actuated with Piezobenders

    Science.gov (United States)

    Copp, Peter

    Helicopter rotor primary control is conventionally carried out using a swashplate with pitch links. Eliminating the swashplate promises to reduce the helicopter's parasitic power in high speed forward flight, as well as may lead to a hydraulic-less vehicle. A Mach-scale swashplateless rotor is designed with integrated piezobender-actuated trailing edge flaps and systematically tested on the benchtop, in the vacuum chamber and on the hoverstand. The blade is nominally based on the UH-60 rotor with a hover tip Mach number of 0.64. The blade diameter is 66 inches requiring 2400 RPM for Mach scale simulation. The rotor hub is modified to reduce the blade fundamental torsional frequency to less than 2.0/rev by replacing the rigid pitch links with linear springs, which results in an increase of the blade pitching response to the trailing edge flaps. Piezoelectric multilayer benders provide the necessary bandwidth, stroke and stiffness to drive the flaps for primary control while fitting inside the blade profile and withstanding the high centrifugal forces. This work focuses on several key issues. A piezobender designed from a soft piezoelectric material, PZT-5K4, is constructed. The new material is used to construct multi-layer benders with increased stroke for the same stiffness relative to hard materials such as PZT-5H2. Each layer has a thickness of 10 mils. The soft material with gold electrodes requires a different bonding method than hard material with nickel electrodes. With this new bonding method, the measured stiffness matches precisely the predicted stiffness for a 12 layer bender with 1.26 inch length and 1.0 inch width with a stiffness of 1.04 lb/mil. The final in-blade bender has a length of 1.38 inches and 1.0 inch width with a stiffness of 0.325 lb/mil and stroke of 20.2 mils for an energy output of 66.3 lb-mil. The behavior of piezobenders under very high electric fields is investigated. High field means +18.9 kV/cm (limited by arcing in air) and -3.54k

  14. Aerodynamics, sensing and control of insect-scale flapping-wing flight

    Science.gov (United States)

    Shyy, Wei; Kang, Chang-kwon; Chirarattananon, Pakpong; Ravi, Sridhar; Liu, Hao

    2016-01-01

    There are nearly a million known species of flying insects and 13 000 species of flying warm-blooded vertebrates, including mammals, birds and bats. While in flight, their wings not only move forward relative to the air, they also flap up and down, plunge and sweep, so that both lift and thrust can be generated and balanced, accommodate uncertain surrounding environment, with superior flight stability and dynamics with highly varied speeds and missions. As the size of a flyer is reduced, the wing-to-body mass ratio tends to decrease as well. Furthermore, these flyers use integrated system consisting of wings to generate aerodynamic forces, muscles to move the wings, and sensing and control systems to guide and manoeuvre. In this article, recent advances in insect-scale flapping-wing aerodynamics, flexible wing structures, unsteady flight environment, sensing, stability and control are reviewed with perspective offered. In particular, the special features of the low Reynolds number flyers associated with small sizes, thin and light structures, slow flight with comparable wind gust speeds, bioinspired fabrication of wing structures, neuron-based sensing and adaptive control are highlighted. PMID:27118897

  15. Aerodynamics, sensing and control of insect-scale flapping-wing flight.

    Science.gov (United States)

    Shyy, Wei; Kang, Chang-Kwon; Chirarattananon, Pakpong; Ravi, Sridhar; Liu, Hao

    2016-02-01

    There are nearly a million known species of flying insects and 13 000 species of flying warm-blooded vertebrates, including mammals, birds and bats. While in flight, their wings not only move forward relative to the air, they also flap up and down, plunge and sweep, so that both lift and thrust can be generated and balanced, accommodate uncertain surrounding environment, with superior flight stability and dynamics with highly varied speeds and missions. As the size of a flyer is reduced, the wing-to-body mass ratio tends to decrease as well. Furthermore, these flyers use integrated system consisting of wings to generate aerodynamic forces, muscles to move the wings, and sensing and control systems to guide and manoeuvre. In this article, recent advances in insect-scale flapping-wing aerodynamics, flexible wing structures, unsteady flight environment, sensing, stability and control are reviewed with perspective offered. In particular, the special features of the low Reynolds number flyers associated with small sizes, thin and light structures, slow flight with comparable wind gust speeds, bioinspired fabrication of wing structures, neuron-based sensing and adaptive control are highlighted.

  16. Numerical Investigation of Flow Control Feasibility with a Trailing Edge Flap

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2014-01-01

    the control system, a standard PID controller is implemented in a finite volume based incompressible flow solver. An immersed boundary method is applied to treat the problem of simulating a deformable airfoil trailing edge. The flow field is solved using a 2D Reynolds averaged Navier-Stokes finite volume......This paper concerns a numerical study of employing an adaptive trailing edge flap to control the lift of an airfoil subject to unsteady inflow conditions. The periodically varying inflow is generated by two oscillating airfoils, which are located upstream of the controlled airfoil. To establish...... solver. In order to more accurately simulate wall bounded flows around the immersed boundary, a modified boundary condition is introduced in the k- ω turbulence model. As an example, turbulent flow over a NACA 64418 airfoil with a deformable trailing edge is investigated. Results from numerical...

  17. The Lateral Port Control Pharyngeal Flap: A Thirty-Year Evolution and Followup

    Directory of Open Access Journals (Sweden)

    Sean Boutros

    2013-01-01

    Full Text Available In 1971, Micheal Hogan introduced the Lateral Port Control Pharyngeal Flap (LPCPF which obtained good results with elimination of VPI. However, there was a high incidence of hyponasality and OSA. We hypothesized that preoperative assessment with videofluoroscopy and nasal endoscopy would enable modification and customization of the LPCPF and result in improvement in the result in both hyponasality and obstructive apnea while still maintaining results in VPI. Thirty consecutive patients underwent customized LPCPF. All patients had preoperative diagnosis of VPI resulting from cleft palate. Patient underwent either videofluoroscopy or nasal endoscopy prior to the planning of surgery. Based on preoperative velar and pharyngeal movement, patients were assigned to wide, medium, or narrow port designs. Patients with significant lateral motion were given wide ports while patients with minimal movement were given narrow ports. There was a 96.66% success rate in the treatment of VPI with one patient with persistent VPI (3.33%. Six patients had mild hyponasality (20 %. Two patients had initial OSA (6.67%, one of which had OSA which lasted longer than six months (3.33%. The modifications of the original flap description have allowed for success in treatment of VPI along with an acceptably low rate of hyponasality and OSA.

  18. Viability and Tissue Quality of Cartilage Flaps From Patients With Femoroacetabular Hip Impingement: A Matched-Control Comparison

    Science.gov (United States)

    Rodriguez-Fontan, Francisco; Payne, Karin A.; Chahla, Jorge; Mei-Dan, Omer; Richards, Abigail; Uchida, Soshi; Pascual-Garrido, Cecilia

    2017-01-01

    Background: Chondrolabral damage is commonly observed in patients with cam-type femoroacetabular impingement (FAI). Chondral flap reattachment has recently been proposed as a possible preservation technique. Purpose/Hypothesis: The purpose of this study was to determine the viability and tissue quality of chondral flaps from patients with FAI at the time of arthroscopy. It was hypothesized that chondral flaps from patients with cam lesions of the hip would exhibit less viability and greater tissue degeneration than would those of a matched control group. Study Design: Cohort study; Level of evidence, 2. Methods: Patients with cam-type FAI who were treated with hip arthroscopy between 2014 and 2016 were asked to participate in this study. The cartilage lesions were localized and classified intraoperatively according to Beck classification. A chondral flap (study group) and a cartilage sample (control group) were obtained from each patient for histologic evaluation. Cellular viability and tissue quality were examined and compared in both groups. Cellular viability was determined with live/dead staining, and tissue quality was evaluated using safranin O/fast green, hematoxylin and eosin (H&E) staining, and immunohistochemistry for collagen II. Osteoarthritis Research Society International (OARSI) grading was used for quality assessment, and Image J software was used to calculate the percentage of tissue viability and Col II stain. Results: A total of 10 male patients with a mean age of 38.4 years (range, 30-55 years) were enrolled. All chondral flaps were classified as Beck grade 4. The mean cellular viability of the chondral flaps was reduced (54.6% ± 25.6%), and they were found to be degenerated (OARSI grade, 4 ± 1.27). Control samples also had reduced viability (38.8% ± 30.3%) and were degenerative (OARSI grade, 3.5 ± 1.38). There was no statistically significant intergroup difference for viability (P = .203) or OARSI grade (P = .645), nor was there an

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

    Science.gov (United States)

    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.

  20. Clinical, radiographic, microbiological, and immunological outcomes of flapped vs. flapless dental implants: a prospective randomized controlled clinical trial.

    Science.gov (United States)

    Tsoukaki, Marina; Kalpidis, Christos D R; Sakellari, Dimitra; Tsalikis, Lazaros; Mikrogiorgis, George; Konstantinidis, Antonis

    2013-09-01

    The objective of this study was to compare the placement of flapped vs. flapless dental implants utilizing clinical, radiographic, microbiological, and immunological parameters. A total of 20 patients received 30 dental implants following a one-stage protocol. The patients were randomly assigned into two study groups: control group with 15 flapped implants and test group with 15 flapless implants. Follow-up examinations were carried out after 1, 2, 6, and 12 weeks. Clinical recordings, sulcular fluid sampling, microbiological analysis, and digital subtraction radiography were utilized to compare the two surgical approaches. Peri-implant sulcus depth was significantly greater in flapped implants at both 6 and 12 postsurgical weeks (P flapless implants. Matrix metalloproteinase-8 values were higher to a statistically significant level in the control group at 1 (P = 0.003) and 6 weeks (P = 0.007) after placement. In the test group, the presence of Porphyromonas gingivalis was significantly higher at the 2nd postoperative week (P = 0.005), whereas the counts of Tannerella forsythia were significantly elevated at the 1st (P = 0.005), 2nd (P = 0.001), and 12th (P = 0.002) postoperative weeks, possibly indicating an earlier formation and maturation of the peri-implant sulcus. Patients reported more pain after flapped implant placement. Flapless implant placement yielded improved clinical, radiographic, and immunological outcomes compared with flapped implantation. In addition, patients seem to better withstand flapless implant placement. © 2012 John Wiley & Sons A/S.

  1. Design, Fabrication, and Structural Evaluation of an Advanced Composite Hydrofoil Control Flap.

    Science.gov (United States)

    1982-11-01

    edge and the flap crank and linkage were required to alleviate two interference problems . The flap crank was attached to the actuator, the strain gage...enancmen system~~~~~~~~~~~~~~~~ an- airtddniypoie anb sdt iea cuaetre dimensional characterizatio ’o h.l..Tepleeh utaoissol eue largert make thog -Rnsmisiong

  2. High-fidelity linear time-invariant model of a smart rotor with adaptive trailing edge flaps

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Hansen, Morten Hartvig

    2017-01-01

    aero-servo-elastic model support the design, systematic tuning and model synthesis of smart rotor control systems. As an example application, the gains of an individual flap controller are tuned using the Ziegler-Nichols method for the full-order poles. The flap controller is based on feedback...... of inverse Coleman transformed and low-pass filtered flapwise blade root moments to the cyclic flap angles through two proportional-integral controllers. The load alleviation potential of the active flap control, anticipated by the frequency response of the linear closed-loop model, is also confirmed by non...

  3. Open-flap versus flapless esthetic crown lengthening: 12-month clinical outcomes of a randomized controlled clinical trial.

    Science.gov (United States)

    Ribeiro, Fernanda V; Hirata, Daniel Y; Reis, André F; Santos, Vanessa R; Miranda, Tamires S; Faveri, Marcelo; Duarte, Poliana M

    2014-04-01

    Excessive gingival display (EGD) has a negative impact on a pleasant smile. Minimally invasive therapeutic modalities have become the standard treatment in many dentistry fields. Therefore, the aim of this study is to compare the clinical outcomes of open-flap (OF) and minimally invasive flapless (FL) esthetic crown lengthening (ECL) for the treatment of EGD. A split-mouth randomized controlled trial was conducted in 28 patients presenting with EGD. Contralateral quadrants received ECL using OF or FL techniques. Clinical parameters were evaluated at baseline and 3, 6, and 12 months post-surgery. The local levels of receptor activator of nuclear factor-κB ligand (RANKL) and osteoprotegerin (OPG) were assessed by enzyme-linked immunosorbent assay at baseline and 3 months. Patients' perceptions regarding morbidity and esthetic appearance were also evaluated. Periodontal tissue dimensions were obtained by computed tomography at baseline and correlated with the changes in the gingival margin (GM). Patients reported low morbidity and high satisfaction with esthetic appearance for both procedures (P >0.05). RANKL and OPG concentrations were increased in the OF group at 3 months (P 0.05). FL and OF surgeries produced stable and similar clinical results up to 12 months. FL ECL may be a predictable alternative approach for the treatment of EGD.

  4. Perforator-Based Interposition Flaps Perform Better Than Full-Thickness Grafts for the Release of Burn Scar Contractures: A Multicenter Randomized Controlled Trial.

    Science.gov (United States)

    Stekelenburg, Carlijn M; Jaspers, Mariëlle E H; Jongen, Sandra J M; Baas, Dominique C; Gardien, Kim L M; Hiddingh, Jakob; van Zuijlen, Paul P M

    2017-02-01

    Burn scar contractures remain a significant problem for the severely burned patient. Reconstructive surgery is often indicated to improve function and quality of life. Skin grafts (preferably full-thickness grafts) are frequently used to cover the defect that remains after scar release. Local flaps are also used for this purpose and provide healthy skin subcutaneous tissue. The vascularization and versatility of local flaps can be further improved by enclosing a perforator at the base of the flap. Until now, no randomized controlled trial has been performed to determine which technique has the best effectiveness in burn scar contracture releasing procedures. A multicenter randomized controlled trial was performed to compare the effectiveness of perforator-based interposition flaps to full-thickness skin grafts for the treatment of burn scar contractures. The primary outcome parameter was change in the surface area of the flap or full-thickness skin graft. Secondary outcome parameters were width, elasticity, color, Patient and Observer Scar Assessment Scale score, and range of motion. Measurements were performed after 3 and 12 months. The mean surface area between flaps (n = 16) and full-thickness skin grafts (n = 14) differed statistically significantly at 3 months (123 percent versus 87 percent; p Scar Assessment Scale observer score and color), interposition flaps showed superior results compared with full-thickness skin grafts. Perforator-based interposition flaps result in a more effective scar contracture release than full-thickness skin grafts and should therefore be preferred over full-thickness skin grafts when possible. Therapeutic, I.

  5. Energy extraction from a semi-passive flapping-foil turbine with active heave and passive pitch

    Science.gov (United States)

    Boudreau, Matthieu; Dumas, Guy; Gunther, Kevin; CFD Laboratory LMFN Team

    2017-11-01

    Due to the inherent complexity of the mechanisms needed to prescribe the heaving and the pitching motions of optimal flapping-foil turbines, several research groups are now investigating the potential of using unconstrained passive motions. The amplitude, the phase and the frequency of such free motions are thus the result of the interaction of the blade with the flow and its elastic supports, namely springs and dampers. In parallel with our current study on fully-passive flapping-foil turbines, we investigate in this work the possibility of using a semi-passive turbine. Unlike previous semi-passive turbines studied in the literature, we propose a turbine with a passive pitching motion and an active heaving motion constrained to be a sine wave with desired amplitude and frequency. As most of the energy extracted by flapping-foil turbines comes from the heaving motion, it is natural to connect an electric generator to this degree of freedom, thereby allowing one to constrain this motion. It is found that large-amplitude pitching motions leading to a considerable energy extraction can arise under different circumstances and mechanisms, either forced by the heaving motion or driven by an instability of the pitching motion itself. The authors gratefully acknowledge the support from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Tyler Lewis Clean Energy Research Foundation, Calcul Québec and Compute Canada.

  6. Active control for performance enhancement of electrically controlled rotor

    Directory of Open Access Journals (Sweden)

    Lu Yang

    2015-10-01

    Full Text Available Electrically controlled rotor (ECR system has the potential to enhance the rotor performance by applying higher harmonic flap inputs. In order to explore the feasibility and effectiveness for ECR performance enhancement using closed-loop control method, firstly, an ECR rotor performance analysis model based on helicopter flight dynamic model is established, which can reflect the performance characteristics of ECR helicopter at high advance ratio. Based on the simulation platform, an active control method named adaptive T-matrix algorithm is adopted to explore the feasibility and effectiveness for ECR performance enhancement. The simulation results verify the effectiveness of this closed-loop control method. For the sample ECR helicopter, about 3% rotor power reduction is obtained with the optimum 2/rev flap inputs at the advance ratio of 0.34. And through analyzing the distributions of attack of angle and drag in rotor disk, the underlying physical essence of ECR power reduction is cleared. Furthermore, the influence of the key control parameters, including convergence factor and weighting matrix, on the effectiveness of closed-loop control for ECR performance enhancement is explored. Some useful results are summarized, which can be used to direct the future active control law design of ECR performance enhancement.

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

    Science.gov (United States)

    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.

  8. Human exonuclease 1 (EXO1) activity characterization and its function on FLAP structures

    DEFF Research Database (Denmark)

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

    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...

  9. A Mission-Adaptive Variable Camber Flap Control System to Optimize High Lift and Cruise Lift-to-Drag Ratios of Future N+3 Transport Aircraft

    Science.gov (United States)

    Urnes, James, Sr.; Nguyen, Nhan; Ippolito, Corey; Totah, Joseph; Trinh, Khanh; Ting, Eric

    2013-01-01

    Boeing and NASA are conducting a joint study program to design a wing flap system that will provide mission-adaptive lift and drag performance for future transport aircraft having light-weight, flexible wings. This Variable Camber Continuous Trailing Edge Flap (VCCTEF) system offers a lighter-weight lift control system having two performance objectives: (1) an efficient high lift capability for take-off and landing, and (2) reduction in cruise drag through control of the twist shape of the flexible wing. This control system during cruise will command varying flap settings along the span of the wing in order to establish an optimum wing twist for the current gross weight and cruise flight condition, and continue to change the wing twist as the aircraft changes gross weight and cruise conditions for each mission segment. Design weight of the flap control system is being minimized through use of light-weight shape memory alloy (SMA) actuation augmented with electric actuators. The VCCTEF program is developing better lift and drag performance of flexible wing transports with the further benefits of lighter-weight actuation and less drag using the variable camber shape of the flap.

  10. Parametric study of fluid flow manipulation with piezoelectric macrofiber composite flaps

    Science.gov (United States)

    Sadeghi, O.; Tarazaga, P.; Stremler, M.; Shahab, S.

    2017-04-01

    Active Fluid Flow Control (AFFC) has received great research attention due to its significant potential in engineering applications. It is known that drag reduction, turbulence management, flow separation delay and noise suppression through active control can result in significantly increased efficiency of future commercial transport vehicles and gas turbine engines. In microfluidics systems, AFFC has mainly been used to manipulate fluid passing through the microfluidic device. We put forward a conceptual approach for fluid flow manipulation by coupling multiple vibrating structures through flow interactions in an otherwise quiescent fluid. Previous investigations of piezoelectric flaps interacting with a fluid have focused on a single flap. In this work, arrays of closely-spaced, free-standing piezoelectric flaps are attached perpendicular to the bottom surface of a tank. The coupling of vibrating flaps due to their interacting with the surrounding fluid is investigated in air (for calibration) and under water. Actuated flaps are driven with a harmonic input voltage, which results in bending vibration of the flaps that can work with or against the flow-induced bending. The size and spatial distribution of the attached flaps, and the phase and frequency of the input actuation voltage are the key parameters to be investigated in this work. Our analysis will characterize the electrohydroelastic dynamics of active, interacting flaps and the fluid motion induced by the system.

  11. 14 CFR 23.699 - Wing flap position indicator.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Wing flap position indicator. 23.699... Construction Control Systems § 23.699 Wing flap position indicator. There must be a wing flap position indicator for— (a) Flap installations with only the retracted and fully extended position, unless— (1) A...

  12. Viability and Tissue Quality of Cartilage Flaps From Patients With Femoroacetabular Hip Impingement: A Matched-Control Comparison

    OpenAIRE

    Rodriguez-Fontan, Francisco; Payne, Karin A.; Chahla, Jorge; Mei-Dan, Omer; Richards, Abigail; Uchida, Soshi; Pascual-Garrido, Cecilia

    2017-01-01

    Background: Chondrolabral damage is commonly observed in patients with cam-type femoroacetabular impingement (FAI). Chondral flap reattachment has recently been proposed as a possible preservation technique. Purpose/Hypothesis: The purpose of this study was to determine the viability and tissue quality of chondral flaps from patients with FAI at the time of arthroscopy. It was hypothesized that chondral flaps from patients with cam lesions of the hip would exhibit less viability and greater t...

  13. Advanced load alleviation for wind turbines using adaptive trailing edge flaps: Sensoring and control

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Peter Bjoern

    2010-02-15

    The purpose of wind turbines and their predecessors the windmill, is to convert the energy in the wind to usable energy forms. Whereas windmills of the past focused on the conversion of wind power to torque for grinding, pumping and winching, modern wind turbines convert the wind energy into electric power. They do so through incorporation of generators, which convert mechanical torque into electricity. Wind turbines are designed to keep the overall cost per produced Kilo Watt hour as low as possible. One way of improving the performance and lifetime of the wind turbine is through active flow control. Active control is often considered costly but if the lifespan of the components can be increased it could be justifiable. This thesis covers various aspects of 'smart control' such as control theory, sensoring, optimization, experiments and numerical modeling. (author)

  14. Precision Position Control of the DelFly II Flapping-wing Micro Air Vehicle in a Wind-tunnel

    NARCIS (Netherlands)

    Cunis, T.; Karasek, M.; de Croon, G.C.H.E.

    2016-01-01

    Flapping-wing MAVs represent an attractive alternative to conventional designs with rotary wings, since they promise a much higher efficiency in forward flight. However, further insight into the flapping-wing aerodynamics is still needed to get closer to the flight performance observed in natural

  15. Survival rate of one-piece dental implants placed with a flapless or flap protocol--a randomized, controlled study: 12-month results.

    Science.gov (United States)

    Froum, Stuart J; Cho, Sang Choon; Elian, Nicholas; Romanos, George; Jalbout, Ziad; Natour, Mazen; Norman, Robert; Neri, Dinah; Tarnow, Dennis P

    2011-01-01

    The purpose of this randomized controlled clinical study was to compare the survival of a one-piece anodically oxidized surface implant when placed with a flapless or flap protocol. Bone loss measurements on radiographs and changes in clinical probing depths 1 year post-definitive restoration placement were recorded and compared. Fifty-two of 60 patients (implants) remained in the study at the 1-year follow-up. At the time of final evaluation, no implant was lost in either group. At the time of placement of the definitive restoration, there was a mean mesial and distal bone gain in both groups compared to bone levels present at the time of implant insertion. There were no significant changes in bone levels between placement of the definitive restoration and those recorded 12 months later, and no significant differences in bone levels between the flap or flapless group at 6 or 12 months were noted. No significant differences were seen either in pocket depth or change in pocket depth at 6 and 12 months in the flapless and flap groups. It was therefore concluded that one-piece anodically oxidized surface implants, 1 year post-definitive restoration insertion, had high survival rates (100%) and stable marginal bone and probing depth levels whether a flapless or flap protocol was used for implant insertion.

  16. Effect of Smart Rotor Control Using a Deformable Trailing Edge Flap on Load Reduction under Normal and Extreme Turbulence

    Directory of Open Access Journals (Sweden)

    Jian Zhong Xu

    2012-09-01

    Full Text Available This paper presents a newly developed aero-servo-elastic platform for implementing smart rotor control and shows its effectiveness with aerodynamic loads on large-scale offshore wind turbines. The platform was built by improving the FAST/Aerodyn codes with the integration of an external deformable trailing edge flap controller in the Matlab/Simulink software. Smart rotor control was applied to an Upwind/NREL 5 MW reference wind turbine under various operating wind conditions in accordance with the IEC Normal Turbulence Model (NTM and Extreme Turbulence Model (ETM. Results showed that, irrespective of whether the NTM or ETM case was considered, aerodynamic load in terms of blade flapwise root moment and tip deflection were effectively reduced. Furthermore, the smart rotor control also positively affected generator power, pitch system and tower load. These results laying a foundation for a future migration of the “smart rotor control” concept into the design of large-scale offshore wind turbines.

  17. Wind-Tunnel Tests of a Bridge Model with Active Vibration Control

    DEFF Research Database (Denmark)

    Hansen, H. I.; Thoft-Christensen, Palle; Mendes, P. A.

    The application of active control systems to reduce wind vibrations in bridges is a new area of research. This paper presents the results that were obtained on a set of wind tunnel tests of a bridge model equipped with active movable flaps. Based on the monitored position and motion of the deck...

  18. Synthetic, structural mimetics of the β-hairpin flap of HIV-1 protease inhibit enzyme function.

    Science.gov (United States)

    Chauhan, Jay; Chen, Shen-En; Fenstermacher, Katherine J; Naser-Tavakolian, Aurash; Reingewertz, Tali; Salmo, Rosene; Lee, Christian; Williams, Emori; Raje, Mithun; Sundberg, Eric; DeStefano, Jeffrey J; Freire, Ernesto; Fletcher, Steven

    2015-11-01

    Small-molecule mimetics of the β-hairpin flap of HIV-1 protease (HIV-1 PR) were designed based on a 1,4-benzodiazepine scaffold as a strategy to interfere with the flap-flap protein-protein interaction, which functions as a gated mechanism to control access to the active site. Michaelis-Menten kinetics suggested our small-molecules are competitive inhibitors, which indicates the mode of inhibition is through binding the active site or sterically blocking access to the active site and preventing flap closure, as designed. More generally, a new bioactive scaffold for HIV-1PR inhibition has been discovered, with the most potent compound inhibiting the protease with a modest K(i) of 11 μM. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Flapless versus open flap implant surgery in partially edentulous patients subjected to immediate loading: 1-year results from a split-mouth randomised controlled trial.

    Science.gov (United States)

    Cannizzaro, Gioacchino; Felice, Pietro; Leone, Michele; Checchi, Vittorio; Esposito, Marco

    2011-01-01

    To evaluate the efficacy of flapless versus open flap implant placement in partially edentulous patients. Forty patients with two separate edentulous areas characterised by residual bone at least 5 mm thick and 10 mm in height had these sites randomised following a split-mouth design to receive at least one implant to each side after flap elevation or not. Implants were first placed in one site, and after 2 weeks in the other site freehand. Implants inserted with a torque >48 Ncm were immediately loaded with full occluding acrylic temporary restorations. Definitive single cemented crowns or screw-retained metal ceramic fixed dental prostheses were delivered after 2 months. Outcome measures were prosthesis and implant failures, complications, postoperative swelling and pain, consumption of analgesics, patient preference, surgical time, marginal bone level changes, and implant stability quotient (ISQ) values. Seventy-six implants were placed flapless and 67 after flap elevation. In the flapless group, four flaps had to be raised to control the direction of the bur, whereas one haemorrhage and one fracture of the buccal bone occurred in two patients of the flap elevation group. Four implants did not reach the planned stability (three belonging to the flapless group) and they were all immediately replaced by larger diameter ones. After 1 year, no drop-outs occurred. Two definitive bridges could not be placed when planned (one in each group) and two crowns had to be remade (one in each group). Two implants failed in each group, all in different patients. There were no statistically significant differences for prosthetic and implant failures, complications, ISQ values and marginal bone levels between groups. However, flapless implant placement required significantly less operation time (17 minutes less, saving almost two-thirds of the time for implant placement), induced less postoperative pain, swelling, analgesic consumption and was preferred by patients. Mean ISQ

  20. Forward flight of swallowtail butterfly with simple flapping motion

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Hiroto [School of Engineering and Applied Sciences, Harvard University, 60 Oxford Street, Cambridge, MA 02138 (United States); Shimoyama, Isao, E-mail: isao@i.u-tokyo.ac.j [Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan)

    2010-06-15

    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.

  1. Phosphate steering by Flap Endonuclease 1 promotes 5′-flap specificity and incision to prevent genome instability

    KAUST Repository

    Tsutakawa, Susan E.

    2017-06-27

    DNA replication and repair enzyme Flap Endonuclease 1 (FEN1) is vital for genome integrity, and FEN1 mutations arise in multiple cancers. FEN1 precisely cleaves single-stranded (ss) 5\\'-flaps one nucleotide into duplex (ds) DNA. Yet, how FEN1 selects for but does not incise the ss 5\\'-flap was enigmatic. Here we combine crystallographic, biochemical and genetic analyses to show that two dsDNA binding sites set the 5\\'polarity and to reveal unexpected control of the DNA phosphodiester backbone by electrostatic interactions. Via phosphate steering\\', basic residues energetically steer an inverted ss 5\\'-flap through a gateway over FEN1\\'s active site and shift dsDNA for catalysis. Mutations of these residues cause an 18,000-fold reduction in catalytic rate in vitro and large-scale trinucleotide (GAA) repeat expansions in vivo, implying failed phosphate-steering promotes an unanticipated lagging-strand template-switch mechanism during replication. Thus, phosphate steering is an unappreciated FEN1 function that enforces 5\\'-flap specificity and catalysis, preventing genomic instability.

  2. Design and stable flight of a 21 g insect-like tailless flapping wing micro air vehicle with angular rates feedback control.

    Science.gov (United States)

    Phan, Hoang Vu; Kang, Taesam; Park, Hoon Cheol

    2017-04-04

    An insect-like tailless flapping wing micro air vehicle (FW-MAV) without feedback control eventually becomes unstable after takeoff. Flying an insect-like tailless FW-MAV is more challenging than flying a bird-like tailed FW-MAV, due to the difference in control principles. This work introduces the design and controlled flight of an insect-like tailless FW-MAV, named KUBeetle. A combination of four-bar linkage and pulley-string mechanisms was used to develop a lightweight flapping mechanism that could achieve a high flapping amplitude of approximately 190°. Clap-and-flings at dorsal and ventral stroke reversals were implemented to enhance vertical force. In the absence of a control surface at the tail, adjustment of the location of the trailing edges at the wing roots to modulate the rotational angle of the wings was used to generate control moments for the attitude control. Measurements by a 6-axis load cell showed that the control mechanism produced reasonable pitch, roll and yaw moments according to the corresponding control inputs. The control mechanism was integrated with three sub-micro servos to realize the pitch, roll and yaw controls. A simple PD feedback controller was implemented for flight stability with an onboard microcontroller and a gyroscope that sensed the pitch, roll and yaw rates. Several flight tests demonstrated that the tailless KUBeetle could successfully perform a vertical climb, then hover and loiter within a 0.3 m ground radius with small variations in pitch and roll body angles.

  3. Experimental validation of a true-scale morphing flap for large civil aircraft applications

    Science.gov (United States)

    Pecora, R.; Amoroso, F.; Arena, M.; Noviello, M. C.; Rea, F.

    2017-04-01

    Within the framework of the JTI-Clean Sky (CS) project, and during the first phase of the Low Noise Configuration Domain of the Green Regional Aircraft - Integrated Technological Demonstration (GRA-ITD, the preliminary design and technological demonstration of a novel wing flap architecture were addressed. Research activities were carried out to substantiate the feasibility of morphing concepts enabling flap camber variation in compliance with the demanding safety requirements applicable to the next generation green regional aircraft, 130- seats with open rotor configuration. The driving motivation for the investigation on such a technology was found in the opportunity to replace a conventional double slotted flap with a single slotted camber-morphing flap assuring similar high lift performances -in terms of maximum attainable lift coefficient and stall angle- while lowering emitted noise and system complexity. Studies and tests were limited to a portion of the flap element obtained by slicing the actual flap geometry with two cutting planes distant 0.8 meters along the wing span. Further activities were then addressed in order to increase the TRL of the validated architecture within the second phase of the CS-GRA. Relying upon the already assessed concept, an innovative and more advanced flap device was designed in order to enable two different morphing modes on the basis of the A/C flight condition / flap setting: Mode1, Overall camber morphing to enhance high-lift performances during take-off and landing (flap deployed); Mode2, Tab-like morphing mode. Upwards and downwards deflection of the flap tip during cruise (flap stowed) for load control at high speed. A true-scale segment of the outer wing flap (4 meters span with a mean chord of 0.9 meters) was selected as investigation domain for the new architecture in order to duly face the challenges posed by real wing installation. Advanced and innovative solutions for the adaptive structure, actuation and control

  4. Flapless vs flapped implant insertion in patients with controlled type 2 diabetes subjected to delayed loading: 1-year follow-up results from a randomised controlled trial.

    Science.gov (United States)

    Agrawal, Kaushal Kishor; Rao, Jitendra; Anwar, Mohd; Singh, Kalpana; Himanshu, D

    2017-01-01

    To compare the outcome of dental implants placed following full-thickness flap surgery with flapless surgery in controlled type 2 diabetic patients. A total of 92 controlled type 2 diabetic patients, who needed missing mandibular first molars to be replaced by implants, were selected for a single-centre, parallel group, double-blinded randomised controlled trial. Patients were randomly allocated into two groups: flap (46 patients) vs flapless (46 patients) implant placement. Implants were loaded with metal-ceramic crowns, 4 months after placement in both groups. Implant and crown success, complications, post-operative pain and swelling, plaque index, sulcular bleeding index, pocket depth and HbA1c level. Follow up examinations were made after 24 h, and on the third and seventh days for soft tissue healing, pain and swelling evaluation; then at 6 months and 12 months (after loading) for dental plaque, sulcular bleeding, pocket depth, and HbA1c level evaluation. After 16 months of implant placement, no dropouts occurred. Five implants failed, two in the flap group and three in the flapless group (4.34% vs 6.52%, McNemar test P = 1, difference = 0.4457, 95% CI of difference = 4.554 to 47.234). Seven prosthesis failures occurred, three in the flap group and four in the flapless group (McNemar test P = 1; difference = 0.4239; 95% CI of difference = 29.95 to 3.86). Two patients in each group were affected by complications. There were statistically insignificant differences in the incidence of complications between the groups (McNemar test P = 1; difference = 0.457; 95% CI of difference = 90.75 to 5.33). After 24 h, the flapped group patients showed significantly greater pain compared with the flapless group (24 h: P = 0.017, difference = 0.37 and 95% CI = 0.673 to -0.067). After the third and seventh postoperative days, the mean pain level in both groups decreased linearly after the treatments (third day: P = 0.183, difference = 0.19 and 95% CI = -0.472 to 0.092; seventh

  5. Wind Tunnel Testing of Active Control System for Bridges

    DEFF Research Database (Denmark)

    Hansen, Henriette I.; Thoft-Christensen, Palle

    This paper describes preparation of wind tunnel testing of the principle of using flaps to control the motion of suspension bridges. The experiment will take place at the Instituto Superior Technico Lisbon, Portugal. The bridge section model is constructed of foam with an aluminium frame. The flaps...

  6. A Controllability Approach for Resonant Compliant Systems : Applied to a Flapping Wing Micro Air Vehicle

    NARCIS (Netherlands)

    Peters, H.J.

    2016-01-01

    This thesis studies a controllability approach for general resonant compliant systems. These systems exploit resonance to obtain a specific dynamic response at relatively low actuation power. This type of systems is often lightweight, is scalable and minimizes frictional losses through the use of

  7. Model predictive control of trailing edge flaps on a wind turbine blade

    DEFF Research Database (Denmark)

    Castaignet, Damien Bruno

    -weighted model predictive control, tuned in order to target only the flapwise blade root loads at the frequencies contributing the most to blade root fatigue damage (the 1P, 2P and 3P frequencies), and to avoid unnecessary wear and tear of the actuators at high frequencies. A disturbance model consisting...

  8. High Lift Common Research Model for Wind Tunnel Testing: An Active Flow Control Perspective

    Science.gov (United States)

    Lin, John C.; Melton, Latunia P.; Viken, Sally A.; Andino, Marlyn Y.; Koklu, Mehti; Hannon, Judith A.; Vatsa, Veer N.

    2017-01-01

    This paper provides an overview of a research and development effort sponsored by the NASA Advanced Air Transport Technology Project to achieve the required high-lift performance using active flow control (AFC) on simple hinged flaps while reducing the cruise drag associated with the external mechanisms on slotted flaps of a generic modern transport aircraft. The removal of the external fairings for the Fowler flap mechanism could help to reduce drag by 3.3 counts. The main challenge is to develop an AFC system that can provide the necessary lift recovery on a simple hinged flap high-lift system while using the limited pneumatic power available on the aircraft. Innovative low-power AFC concepts will be investigated in the flap shoulder region. The AFC concepts being explored include steady blowing and unsteady blowing operating in the spatial and/or temporal domain. Both conventional and AFC-enabled high-lift configurations were designed for the current effort. The high-lift configurations share the cruise geometry that is based on the NASA Common Research Model, and therefore, are also open geometries. A 10%-scale High Lift Common Research Model (HL-CRM) is being designed for testing at the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel during fiscal year 2018. The overall project plan, status, HL-CRM configurations, and AFC objectives for the wind tunnel test are described.

  9. Study to eliminate ground resonance using active controls

    Science.gov (United States)

    Straub, F. K.

    1984-01-01

    The effectiveness of active control blade feathering in increasing rotor body damping and the possibility to eliminate ground resonance instabilities were investigated. An analytical model representing rotor flapping and lead-lag degrees of freedom and body pitch, roll, longitudinal and lateral motion is developed. Active control blade feathering is implemented as state variable feedback through a conventional swashplate. The influence of various feedback states, feedback gain, and weighting between the cyclic controls is studied through stability and response analyses. It is shown that blade cyclic inplane motion, roll rate and roll acceleration feedback can add considerable damping to the system and eliminate ground resonance instabilities, which the feedback phase is also a powerful parameter, if chosen properly, it maximizes augmentation of the inherent regressing lag mode damping. It is shown that rotor configuration parameters, like blade root hinge offset, flapping stiffness, and precone considerably influence the control effectiveness. It is found that active control is particularly powerful for hingeless and bearingless rotor systems.

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

    NARCIS (Netherlands)

    Barlas, T; Jost, E.; Pirrung, G.; Tsiantas, T.; Navalkar, S.T.; Lutz, T.; van Wingerden, J.W.; Bossanyi, E.; Chaviaropoulos, T.; Cheng, P.W.

    2016-01-01

    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

  11. DNA and Protein Requirements for Substrate Conformational Changes Necessary for Human Flap Endonuclease-1-catalyzed Reaction*

    Science.gov (United States)

    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

  12. Mechanics of Flapping Flight: Analytical Formulations of Unsteady Aerodynamics, Kinematic Optimization, Flight Dynamics, and Control

    Science.gov (United States)

    Taneja, Jayant Kumar

    Electricity is an indispensable commodity to modern society, yet it is delivered via a grid architecture that remains largely unchanged over the past century. A host of factors are conspiring to topple this dated yet venerated design: developments in renewable electricity generation technology, policies to reduce greenhouse gas emissions, and advances in information technology for managing energy systems. Modern electric grids are emerging as complex distributed systems in which a portfolio of power generation resources, often incorporating fluctuating renewable resources such as wind and solar, must be managed dynamically to meet uncontrolled, time-varying demand. Uncertainty in both supply and demand makes control of modern electric grids fundamentally more challenging, and growing portfolios of renewables exacerbate the challenge. We study three electricity grids: the state of California, the province of Ontario, and the country of Germany. To understand the effects of increasing renewables, we develop a methodology to scale renewables penetration. Analyzing these grids yields key insights about rigid limits to renewables penetration and their implications in meeting long-term emissions targets. We argue that to achieve deep penetration of renewables, the operational model of the grid must be inverted, changing the paradigm from load-following supplies to supply-following loads. To alleviate the challenge of supply-demand matching on deeply renewable grids, we first examine well-known techniques, including altering management of existing supply resources, employing utility-scale energy storage, targeting energy efficiency improvements, and exercising basic demand-side management. Then, we create several instantiations of supply-following loads -- including refrigerators, heating and cooling systems, and laptop computers -- by employing a combination of sensor networks, advanced control techniques, and enhanced energy storage. We examine the capacity of each load

  13. The wonders of flap endonucleases: structure, function, mechanism and regulation.

    Science.gov (United States)

    Finger, L David; Atack, John M; Tsutakawa, Susan; Classen, Scott; Tainer, John; Grasby, Jane; Shen, Binghui

    2012-01-01

    Processing of Okazaki fragments to complete lagging strand DNA synthesis requires coordination among several proteins. RNA primers and DNA synthesised by DNA polymerase α are displaced by DNA polymerase δ to create bifurcated nucleic acid structures known as 5'-flaps. These 5'-flaps are removed by Flap Endonuclease 1 (FEN), a structure-specific nuclease whose divalent metal ion-dependent phosphodiesterase activity cleaves 5'-flaps with exquisite specificity. FENs are paradigms for the 5' nuclease superfamily, whose members perform a wide variety of roles in nucleic acid metabolism using a similar nuclease core domain that displays common biochemical properties and structural features. A detailed review of FEN structure is undertaken to show how DNA substrate recognition occurs and how FEN achieves cleavage at a single phosphate diester. A proposed double nucleotide unpairing trap (DoNUT) is discussed with regards to FEN and has relevance to the wider 5' nuclease superfamily. The homotrimeric proliferating cell nuclear antigen protein (PCNA) coordinates the actions of DNA polymerase, FEN and DNA ligase by facilitating the hand-off intermediates between each protein during Okazaki fragment maturation to maximise through-put and minimise consequences of intermediates being released into the wider cellular environment. FEN has numerous partner proteins that modulate and control its action during DNA replication and is also controlled by several post-translational modification events, all acting in concert to maintain precise and appropriate cleavage of Okazaki fragment intermediates during DNA replication.

  14. Efficient flapping flight of pterosaurs

    Science.gov (United States)

    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

  15. Free anterolateral thigh flap

    Directory of Open Access Journals (Sweden)

    Zoran M. Arnež

    2006-05-01

    Full Text Available Background: For reconstruction of soft tissue defects in reconstructive microsurgery after ablation of tumors or following trauma flaps having following characteristics are being searched for: large surface, long vascular pedicle with large diameter of vessels, possibility of transfer of multiple tissues (skin, muscle, fascia, tendons, bone on the same nutrient vessels, independent movement of different components of the flap in space, harvesting in supine position and primary donor site closure. Many of these characteristics are being met by the radial forearm flap however its main dissadvantage remains donor site closure by split thickness skin grafts. This can be avoided by the use of the anterolateral thigh (ALT flap.Methods: The ALT flap is raised, like other perforator flaps, arround the septocutaneous perforator, which is located by Doppler ultrasound at midpoint on the line connecting anterior superior iliac spine and upper lateral border of patella or arround musculocutaneous perforators. Vascular pedicle can be made longer by harvesting of the descendent branch of the lateral circomflex femoral artery.Results: We report the first successfull free ALT flap transfer for soft tissue reconstruction of oral cavity and cheek after ablation of a recurrency of a malignant tumor in Slovenia.Conclusions: Because of its proprieties the ALT flap is suitable for reconstruction of defects on head and neck and extremities following tumor ablation or trauma. Because of its advantages it will replace also in our country the radial forearm flap which is the most popular flap in Slovenija for these indications.

  16. New drag laws for flapping flight

    Science.gov (United States)

    Agre, Natalie; Zhang, Jun; Ristroph, Leif

    2014-11-01

    Classical aerodynamic theory predicts that a steadily-moving wing experiences fluid forces proportional to the square of its speed. For bird and insect flight, however, there is currently no model for how drag is affected by flapping motions of the wings. By considering simple wings driven to oscillate while progressing through the air, we discover that flapping significantly changes the magnitude of drag and fundamentally alters its scaling with speed. These measurements motivate a new aerodynamic force law that could help to understand the free-flight dynamics, control, and stability of insects and flapping-wing robots.

  17. Propeller TAP flap

    DEFF Research Database (Denmark)

    Thomsen, Jørn Bo; Bille, Camilla; Wamberg, Peter

    2013-01-01

    The aim of this study was to examine if a propeller thoracodorsal artery perforator (TAP) flap can be used for breast reconstruction. Fifteen women were reconstructed using a propeller TAP flap, an implant, and an ADM. Preoperative colour Doppler ultrasonography was used for patient selection...... to identify the dominant perforator in all cases. A total of 16 TAP flaps were performed; 12 flaps were based on one perforator and four were based on two. A permanent silicone implant was used in 14 cases and an expander implant in two. Minor complications were registered in three patients. Two cases had...... major complications needing additional surgery. One flap was lost due to a vascular problem. Breast reconstruction can be performed by a propeller TAP flap without cutting the descending branch of the thoracodorsal vessels. However, the authors would recommend that a small cuff of muscle is left around...

  18. Implementation of CPFD to Control Active and Passive Airfoil Propulsion

    Science.gov (United States)

    Young, Jay; Asselin, Daniel; Williamson, Charles

    2016-11-01

    The fluid dynamics of biologically-inspired flapping propulsion provides a fertile testing ground for the field of unsteady aerodynamics, serving as important groundwork for the design and development of fast, mobile underwater vehicles and flapping-wing micro air vehicles (MAVs). There has been a recent surge of interest in these technologies as they provide low cost, compact, and maneuverable means for terrain mapping, search and rescue operations, and reconnaissance. Propulsion by unsteady motions has been fundamentally modeled with an airfoil that heaves and pitches, and previous work has been done to show that actively controlling these motions can generate high thrust and efficiency (Read, Hover & Triantafyllou 2003). In this study, we examine the performance of an airfoil with an actuated heave motion coupled with a passively controlled pitch motion created by simulating the presence of a torsional spring using our cyber-physical fluid dynamics (CPFD) approach (Mackowski & Williamson 2011, 2015, 2016). By using passively controlled pitch, we have effectively eliminated an actuator, decreasing cost and mass, an important step for developing efficient vehicles. In many cases, we have achieved comparable or superior thrust and efficiency values to those obtained using two actively controlled degrees of freedom. This work was supported by the National Science Foundation and the Air Force Office of Scientific Research Grant No. FA9550-15-1-0243, monitored by Dr. Douglas Smith.

  19. Active noise control primer

    CERN Document Server

    Snyder, Scott D

    2000-01-01

    Active noise control - the reduction of noise by generating an acoustic signal that actively interferes with the noise - has become an active area of basic research and engineering applications. The aim of this book is to present all of the basic knowledge one needs for assessing how useful active noise control will be for a given problem and then to provide some guidance for designing, setting up, and tuning an active noise-control system. Written for students who have no prior knowledge of acoustics, signal processing, or noise control but who do have a reasonable grasp of basic physics and mathematics, the book is short and descriptive. It leaves for more advanced texts or research monographs all mathematical details and proofs concerning vibrations, signal processing and the like. The book can thus be used in independent study, in a classroom with laboratories, or in conjunction with a kit for experiment or demonstration. Topics covered include: basic acoustics; human perception and sound; sound intensity...

  20. Effect of implant support for prostheses on electromyographic activity of masseter muscle and jaw movement in patients after mandibular fibula free flap reconstruction.

    Science.gov (United States)

    Fueki, Kenji; Roumanas, Eleni D; Blackwell, Keith E; Freymiller, Earl; Abemayor, Elliot; Wong, Weng Kee; Kapur, Krishan K; Garrett, Neal

    2014-01-01

    Dental implants are used to stabilize, support, and retain prostheses in the mandible following fibula free flap reconstruction. A previous longitudinal prospective study showed that an implant-supported prosthesis (IP) provided additional improvement in masticatory performance compared to a conventional prosthesis (CP). Therefore, in this paper, the impact of implant retention and support of mandibular prostheses on neuromuscular function is reported via a within-subject analysis. Forty-six participants were enrolled in the study. Prosthetic treatment with a CP was completed in 33 subjects following oromandibular resection and fibula free flap reconstruction. Twenty-five subjects completed evaluation of the CP after an adaptation period. Standardized masticatory tests with peanuts were given to subjects on the defect and nondefect chewing sides. Electromyography (EMG) of masseter muscles and jaw movement was performed and recorded simultaneously in 19 of these subjects. IP treatment was then completed in 16 of these subjects, and 15 of them participated in the IP evaluation after an adaptation period. Of these 15 subjects, 13 completed EMG and jaw movement recordings for both CP and IP. EMG activity of the defect-side masseter muscle increased significantly from CP to IP conditions when chewing on either side, but no significant change was found for nondefect-side muscle activity. Jaw movement parameters showed no significant changes from CP to IP. In patients restored with mandibular fibula free flap reconstruction, implant support for mandibular prostheses has the benefit of permitting greater muscle effort on the defect side, irrespective of the side on which the bolus is being chewed. The impact of an IP on jaw movements is limited.

  1. Effect of inhibiting P38MAPK on inflammatory factors and cell apoptosis during flap ischemia-reperfusion injury

    Directory of Open Access Journals (Sweden)

    Tuo Chen

    2017-05-01

    Full Text Available Objective: To study the effect of inhibiting P38 mitogen activated protein kinase (P38MAPK on inflammatory factors and cell apoptosis during flap ischemia-reperfusion injury. Methods: Wistar rats were selected as experimental animals and randomly divided into control group, model group and intervention group (n=12, control group were made into routine abdominal superficial arteriovenous flap models, model group were made into ischemia-reperfusion flap models and intervention group were made into ischemia-reperfusion flap models and then received SB202190 intervention. 8 d after flap making, tissue was collected to detect the expression of inflammatory factors and apoptosis molecules as well as the levels of oxidative stress indicators. Results: NF-κB, IL-6, TNF-α, Bax and Caspase-3 mRNA expression and protein expression in flap tissue of model group were significantly higher than those of control group (P<0.05, ROS, MDA, AOPP and 8-OHdG levels were significantly higher than those of control group, and Bcl-2 mRNA expression and protein expression were significantly lower than those of control group (P<0.05; NF-κB, IL-6, TNF-α, Bax and Caspase-3 mRNA expression and protein expression in flap tissue of intervention group were significantly lower than those of model group (P<0.05, ROS, MDA, AOPP and 8-OHdG levels were significantly lower than those of model group (P<0.05, and Bcl-2 mRNA expression and protein expression were significantly higher than those of model group (P<0.05. Conclusions: Inhibiting P38MAPK can reduce the transplanted flap ischemia-reperfusion injury caused by inflammation, oxidative stress and cell apoptosis.

  2. Aerodynamics power consumption for mechanical flapping wings undergoing flapping and pitching motion

    Science.gov (United States)

    Razak, N. A.; Dimitriadis, G.; Razaami, A. F.

    2017-07-01

    Lately, due to the growing interest in Micro Aerial Vehicles (MAV), interest in flapping flight has been rekindled. The reason lies in the improved performance of flapping wing flight at low Reynolds number regime. Many studies involving flapping wing flight focused on the generation of unsteady aerodynamic forces such as lift and thrust. There is one aspect of flapping wing flight that received less attention. The aspect is aerodynamic power consumption. Since most mechanical flapping wing aircraft ever designed are battery powered, power consumption is fundamental in improving flight endurance. This paper reports the results of experiments carried out on mechanical wings under going active root flapping and pitching in the wind tunnel. The objective of the work is to investigate the effect of the pitch angle oscillations and wing profile on the power consumption of flapping wings via generation of unsteady aerodynamic forces. The experiments were repeated for different airspeeds, flapping and pitching kinematics, geometric angle of attack and wing sections with symmetric and cambered airfoils. A specially designed mechanical flapper modelled on large migrating birds was used. It will be shown that, under pitch leading conditions, less power is required to overcome the unsteady aerodnamics forces. The study finds less power requirement for downstroke compared to upstroke motion. Overall results demonstrate power consumption depends directly on the unsteady lift force.

  3. Fundamental Experimental and Numerical Investigation of Active Control of 3-D Flows

    Science.gov (United States)

    2011-10-06

    e.g., flaps, aileron , rudder, etc.) with active flow control, or at least augment their performance in terms of control authority as well as...a cross-flow. Furthermore, these studies involved synthetic jets that were issued through orifices of different geometry ranging between: (i) plane ...anemometry; which included both near- and far-field measurements as well as measurements on two planes along and across the slit. They showed that besides

  4. Experimental and computational studies of active flow control on a model truck-trailer

    Directory of Open Access Journals (Sweden)

    Jahanmiri Mohsen

    2012-04-01

    Full Text Available Active flow control is probably the most challenging research area in vehicle aerodynamics. Being able to manipulate a flow field in order to achieve desired results beneficial to engineering is the only way to meet today’s demands for competitive and efficient solutions in the automotive industry. The current work studies the flow control on a semi detailed model truck by using detached-eddy simulations and wind tunnel experiments aiming at reducing the aerodynamic drag. This study combines both passive and active flow control applied on the rear end of the trailer. An indigenous fluidic actuator (loudspeaker in cavity with slots is used as a synthetic jet in the experiment. Both experiments and computations demonstrate that the active flow control works successfully and results in flow reattachment to the flaps. The numerical simulations show that the drag coefficient, CD decreased by 3.9% when AFC was activated compared to the baseline case without flaps. The corresponding decrease when AFC was deactivated (with flaps was only 0.7%. The experimental results show a decrease of CD by 3.1% for the case with activated AFC compared to the baseline case. When AFC was deactivated the corresponding decrease in CD was 1.8%. A detailed flow analysis made in computations and experiments is used to explain these results.

  5. Aerodynamic effects of flexibility in flapping wings.

    Science.gov (United States)

    Zhao, Liang; Huang, Qingfeng; Deng, Xinyan; Sane, Sanjay P

    2010-03-06

    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

  6. Aerodynamic effects of flexibility in flapping wings

    Science.gov (United States)

    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

  7. Active Flow Control at Low Reynolds Numbers on a NACA 0015 Airfoil

    Science.gov (United States)

    Melton, LaTunia Pack; Hannon, Judith; Yao, Chung-Sheng; Harris, Jerome

    2008-01-01

    Results from a low Reynolds number wind tunnel experiment on a NACA 0015 airfoil with a 30% chord trailing edge flap tested at deflection angles of 0, 20, and 40 are presented and discussed. Zero net mass flux periodic excitation was applied at the ap shoulder to control flow separation for flap deflections larger than 0. The primary objective of the experiment was to compare force and moment data obtained from integrating surface pressures to data obtained from a 5-component strain-gage balance in preparation for additional three-dimensional testing of the model. To achieve this objective, active flow control is applied at an angle of attack of 6 where published results indicate that oscillatory momentum coefficients exceeding 1% are required to delay separation. Periodic excitation with an oscillatory momentum coefficient of 1.5% and a reduced frequency of 0.71 caused a significant delay of separation on the airfoil with a flap deflection of 20. Higher momentum coefficients at the same reduced frequency were required to achieve a similar level of flow attachment on the airfoil with a flap deflection of 40. There was a favorable comparison between the balance and integrated pressure force and moment results.

  8. Pedicled perforator flaps

    DEFF Research Database (Denmark)

    Demirtas, Yener; Ozturk, Nuray; Kelahmetoglu, Osman

    2009-01-01

    adequately to cover the defect. Defects measuring 3 x 3 cm up to 20 x 20 cm at diverse locations were successfully reconstructed in 20 of 21 patients with 26 flaps. Pedicled perforator flaps offer us reliable and satisfactory results of reconstruction at different anatomic territories of the body. It sounds...

  9. Preliminary Design and Evaluation of an Airfoil with Continuous Trailing-Edge Flap

    Science.gov (United States)

    Shen, Jinwei; Thornburgh, Robert P.; Kreshock, Andrew R.; Wilbur, Matthew L.; Liu, Yi

    2012-01-01

    This paper presents the preliminary design and evaluation of an airfoil with active continuous trailing-edge flap (CTEF) as a potential rotorcraft active control device. The development of structural cross-section models of a continuous trailing-edge flap airfoil is described. The CTEF deformations with MFC actuation are predicted by NASTRAN and UM/VABS analyses. Good agreement is shown between the predictions from the two analyses. Approximately two degrees of CTEF deflection, defined as the rotation angle of the trailing edge, is achieved with the baseline MFC-PZT bender. The 2D aerodynamic characteristics of the continuous trailing-edge flap are evaluated using a CFD analysis. The aerodynamic efficiency of a continuous trailing-edge flap is compared to that of a conventional discrete trailing-edge flap (DTEF). It is found that the aerodynamic characteristics of a CTEF are equivalent to those of a conventional DTEF with the same deflection angle but with a smaller flap chord. A fluid structure interaction procedure is implemented to predict the deflection of the continuous trailingedge flap under aerodynamic pressure. The reductions in CTEF deflection are overall small when aerodynamic pressure is applied: 2.7% reduction is shown with a CTEF deflection angle of two degrees and at angle of attack of six degrees. In addition, newly developed MFC-PMN actuator is found to be a good supplement to MFC-PZT when applied as the bender outside layers. A mixed MFC-PZT and MFC-PMN bender generates 3% more CTEF deformation than an MFC-PZT only bender and 5% more than an MFC-PMN only bender under aerodynamic loads.

  10. Wake Characteristics of a Flapping Wing Optimized for both Aerial and Aquatic Flight

    Science.gov (United States)

    Izraelevitz, Jacob; Kotidis, Miranda; Triantafyllou, Michael

    2017-11-01

    Multiple aquatic bird species (including murres, puffins, and other auks) employ a single actuator to propel themselves in two different fluid media: both flying and swimming using primarily their flapping wings. This impressive design compromise could be adopted by engineered implementations of dual aerial/aquatic robotic platforms, as it offers an existence proof for favorable flow physics. We discuss one realization of a 3D flapping wing actuation system for use in both air and water. The wing oscillates by the root and employs an active in-line motion degree-of-freedom. An experiment-coupled optimization routine generates the wing trajectories, controlling the unsteady forces throughout each flapping cycle. We elucidate the wakes of these wing trajectories using dye visualization, correlating the wake vortex structures with simultaneous force measurements. After optimization, the wing generates the large force envelope necessary for propulsion in both fluid media, and furthermore, demonstrate improved control over the unsteady wake.

  11. Comparative study of Emdogain and coronally advanced flap technique in the treatment of human gingival recessions. A prospective controlled clinical study.

    Science.gov (United States)

    Hägewald, Stefan; Spahr, Axel; Rompola, Eirini; Haller, Bernd; Heijl, Lars; Bernimoulin, Jean-Pierre

    2002-01-01

    Various surgical techniques have been proposed for coverage of denuded root surfaces. The aim of this study was to evaluate a comparison of coronally repositioned flap procedure with or without the use of enamel matrix proteins in the treatment of recession defects. This study was an intra-individual longitudinal test of 12 months duration conducted as a blinded, split-mouth, placebo-controlled and randomised design. It was performed in 2 dental schools. 36 patients, aged 22-62 years, with 2 paired buccal recession defects of at least 3 mm participated. Surgical recession coverage was performed as coronally-advanced flap technique at both sites in the same session. One site was additionally treated with commercially-available enamel matrix proteins (Emdogain) and the other site with placebo (propylene glycol alginate) in accordance with the randomisation list. A blinded examiner assessed pre- and post-surgical measurements. Clinical measurements and photographs were taken pre-surgically and after 1 week, 3 weeks, 3 months, 6 months and 12 months, postoperatively. Measurements comprised height and width of the gingival recession, height of keratinized tissue, probing attachment level, probing pocket depth and alveolar bone level by periodontal probe, Florida Probe or caliper to the nearest 0.5 mm. 12 months after therapy, both treatment modalities showed significant root coverage and probing attachment gain. Gingival recession decreased from 3.7 mm to 0.8 mm for the Emdogain treated sites and from 3.9 mm to 1.0 mm for the control sites, corresponding to mean root coverages of 80% and 79%, respectively. This difference was not significant. With the exception of keratinized tissue gain, which was significantly higher (p=0.003) in the Emdogain group, all other clinical variables were not different in the between-group comparison. As the additional use of Emdogain together with coronally advanced flap technique for recession coverage showed no difference in the overall

  12. Non-viral VEGF165 gene therapy ? magnetofection of acoustically active magnetic lipospheres (?magnetobubbles?) increases tissue survival in an oversized skin flap model

    OpenAIRE

    Holzbach, Thomas; Vlaskou, Dialekti; Neshkova, Iva; Konerding, Moritz A.; W?rtler, Klaus; Mykhaylyk, Olga; G?nsbacher, Bernd; Machens, H-G; Plank, Christian; Giunta, Riccardo E

    2008-01-01

    Abstract Adenoviral transduction of the VEGF gene in an oversized skin flap increases flap survival and perfusion. In this study, we investigated the potential of magnetofection of magnetic lipospheres containing VEGF165-cDNA on survival and perfusion of ischemic skin flaps and evaluated the method with respect to the significance of applied magnetic field and ultrasound. We prepared perfluoropropane-filled magnetic lipospheres (?magnetobubbles?) from Tween60-coated magnetic nanoparticles, Me...

  13. Immediately observation on post-LASIK corneal flap

    Directory of Open Access Journals (Sweden)

    Kun Wu

    2014-08-01

    Full Text Available AIM:To immediately observe the complication of corneal flap after LASIK surgery.METHODS:A retrospective case series were studies.Totally 2 040 cases(4 080 eyesfrom January 2010 to October 2012 in our hospital were collected, the corneal flap was observed using lamp microscope after LASIK within 30min. Corneal flap dislocation, corneal flap strial and intraface debris were examined after operation, the effective treatment and controlled measure should be taken for these complications.RESULTS: Postoperative complications were corneal flap dislocation 102 eyes(2.5%, corneal flapstriae 95 eyes(2.33%, interface debris 105 eyes(2.57%. No failure case was seen. There had no corneal flap-related complications, which seriously impact the visual quality after the surgery.CONCLUSION: Carefully postoperative examination at the first-time is an effective way to manage some complications of post-LASIK. Thus promoting the diagnosis and treatment of post-LASIK complications.

  14. Investigation at transonic speeds of the lateral-control and hinge-moment characteristics of a flap-type spoiler aileron on a 60 degree delta wing

    Science.gov (United States)

    Wiley, Harleth G; Taylor, Robert T

    1954-01-01

    This paper present results of an investigation of the lateral-control and hinge-moment characteristics of a 0.67 semispan flap-type spoiler aileron on a semispan thin 60 degree delta wing at transonic speeds by the reflection-plane technique. The spoiler-aileron had a constant chord of 10.29 percent mean aerodynamic chord and was hinged at the 81.9-percent-wing-root-chord station. Tests were made with the spoiler aileron slot open, partially closed, and closed. Incremental rolling-moment coefficients were obtained through a Mach number range of 0.62 to 1.08. Results indicated reasonably linear variations of rolling-moment and hinge-moment coefficients with spoiler projection except at spoiler projections of less than -2 percent mean aerodynamic chord and angles of attack greater than 12 degrees with results generally independent of slot geometry.

  15. The effect of local application of natural hirudin on random pattern skin flap microcirculation in a porcine model.

    Science.gov (United States)

    Yin, Guo-Qian; Sun, Zhi-Yong; Wang, Gang

    2014-07-01

    The aim of this study was to investigate the effect of local administration of hirudin in improving random pattern skin flap microcirculation in a porcine model. Five Chinese minipigs were used and six dorsal random pattern skin flaps were elevated in each animal (4 × 14 cm). All flaps (n = 30) were assigned to experimental (n = 10), control (n = 10), and sham (n = 10) groups. Flap edema measurement showed that edema in experimental flaps was more severe (P skin flap microcirculation in over dimensioned random pattern skin flaps in a porcine model.

  16. Microporous Polysaccharide Hemospheres Potentiate Ischemia-Induced Skin Flap Necrosis in a Murine Model.

    Science.gov (United States)

    Offodile, Anaeze C; Chen, Bin; Aherrera, Andrew S; Guo, Lifei

    2017-01-01

    Microporous polysaccharide hemospheres are an increasingly used adjunctive measure for obtaining operative field hemostasis. However, the impact of these agents on survival of vascularly challenged tissues is unknown. The aim of this study was to investigate the effect, if any, of microporous hemospheres on tissue survival in a murine model. Eighteen Sprague-Dawley rats underwent creation of two flanking dorsal, modified McFarlane-style flaps using a length-to-width ratio of 4:1. Microporous polysaccharide hemospheres were applied to the underside of only one flap in each animal. In a subset of five rats, tissue malondialdehyde activity was measured at 24 hours. The remaining 13 animals were killed after 7 days, and the area of flap necrosis was measured photographically. Histopathologic analysis was also performed on the margins of the necrotic area. Size comparison showed a significantly larger area of necrosis in the microporous polysaccharide hemosphere-treated flaps relative to controls (1.69 ± 1.21 cm versus 0.28 ± 0.28 cm; p = 0.00135). Higher malondialdehyde levels were also found in the microporous polysaccharide hemosphere-treated flaps at 24 hours (0.462 ± 0.098 versus 0.315 ± 0.065; p = 0.047). The areas of skin necrosis were noted to be partial thickness on histologic examination. Microporous polysaccharide hemospheres are associated with an increased incidence of distal tip necrosis in dorsal rat skin flaps. Despite their efficacy in surgical hemostasis, their use should be judicious, especially with marginally perfused tissues such as mastectomy skin flaps.

  17. Evaluation of a new jet flap propulsive-lift system for turbofan-powered STOL transports

    Science.gov (United States)

    Chin, Y. T.; Aiken, T. N.; Oates, G. S., Jr.

    1974-01-01

    A large-scale STOL transport model with a new jet flap propulsive-lift system was subject to wind-tunnel testing. Aerodynamically, this IBF system combines the benefits of the jet flap and the mechanical flap with boundary layer control. Structurally, it creates its own spanwise air duct with the deflection of the mechanical flap. An additional short-chord control flap, located at the jet-flap exit, provides a powerful means for flight path and lateral controls. The results show that the overall effectiveness of this flap system compares well with other jet flap propulsive-lift systems. A preliminary study based on the wind-tunnel data was made on a medium-size IBF STOL jet transport configuration for a typical-military mission. This study showed that the IBF results in a configuration with a relatively low T/W ratio, making the system an attractive candidate for future designs.

  18. Hypothyroidism improves random-pattern skin flap survival in rats.

    Science.gov (United States)

    Rahimpour, Sina; Nezami, Behtash Ghazi; Karimian, Negin; Sotoudeh-Anvari, Maryam; Ebrahimi, Farzad; Taleb, Shayandokht; Mirazi, Naser; Dehpour, Ahmad Reza

    2012-11-01

    The protective effect of hypothyroidism against ischemic or toxic conditions has been shown in various tissues. We investigated the effect of propylthiouracil (PTU)/methimazole (MMI)-induced hypothyroidism and acute local effect of MMI on the outcome of lethal ischemia in random-pattern skin flaps. Dorsal flaps with caudal pedicles were elevated at midline and flap survival was measured at the seventh day after surgery. The first group, as control, received 1 mL of 0.9% saline solution in the flap before flap elevation. In groups 2 and 3, hypothyroidism was induced by administration of either PTU 0.05% or MMI 0.04% in drinking water. The next four groups received local injections of MMI (10, 20, 50, or 100 μg/flap) before flap elevation. Local PTU injection was ignored due to insolubility of the agent. Hypothyroidism was induced in chronic PTU- and MMI-treated groups, and animals in these groups showed significant increase in their flap survival, compared to control euthyroid rats (79.47% ± 10.49% and 75.48% ± 12.93% versus 52.26% ± 5.75%, respectively, P hypothyroidism improves survival of random-pattern skin flaps in rats. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. A 2.3 A resolution structure of chymosin complexed with a reduced bond inhibitor shows that the active site beta-hairpin flap is rearranged when compared with the native crystal structure

    NARCIS (Netherlands)

    Groves, M R; Dhanaraj, V; Badasso, M; Nugent, P; Pitts, J E; Hoover, D J; Blundell, T L

    1998-01-01

    In the crystal structure of uncomplexed native chymosin, the beta-hairpin at the active site, known as 'the flap', adopts a different conformation from that of other aspartic proteinases. This conformation would prevent the mode of binding of substrates/inhibitors generally found in other aspartic

  20. Prediction of flap response.

    Science.gov (United States)

    Potgieter, Frederik J; Roberts, Cynthia; Cox, Ian G; Mahmoud, Ashraf M; Herderick, Edward E; Roetz, Marlize; Steenkamp, Wouter

    2005-01-01

    To find predictors of the induced biomechanical and optical effects of lamellar flap creation on the cornea. Optimed Eye and Laser Clinic, Pretoria, South Africa, and the Department of Ophthalmology and Biomedical Engineering Center, The Ohio State University, Columbus, Ohio, and Bausch & Lomb Vision Research Laboratory, Rochester, New York, USA. This prospective study monitored the refractive, wavefront aberration, and corneal topographic changes in 29 eyes of 15 patients for 3 months after the creation of a corneal lamellar flap. The main outcome measures for statistical analysis were refraction, total corneal thickness, residual corneal bed thickness, horizontal white-to-white corneal diameter, horizontal flap diameter, topography data, and wavefront data. Statistically significant changes were seen in the autorefraction mode. Wavefront data showed significant change in 4 Zernike modes-90/180-degree astigmatism, vertical coma, horizontal coma, and spherical aberration. The topography data indicated the corneal biomechanical response was significantly predicted by stromal bed thickness in the early follow-up period and by total corneal pachymetry and flap diameter in a 2-parameter statistical model in the late follow-up period. Uncomplicated lamellar flap creation is responsible for systematic changes in corneal topography and induction of higher-order optical aberrations. Predictors of this response include stromal bed thickness, flap diameter, and total corneal pachymetry.

  1. Non-viral VEGF165 gene therapy – magnetofection of acoustically active magnetic lipospheres (‘magnetobubbles’) increases tissue survival in an oversized skin flap model

    Science.gov (United States)

    Holzbach, Thomas; Vlaskou, Dialekti; Neshkova, Iva; Konerding, Moritz A; Wörtler, Klaus; Mykhaylyk, Olga; Gänsbacher, Bernd; Machens, H-G; Plank, Christian; Giunta, Riccardo E

    2010-01-01

    Abstract Adenoviral transduction of the VEGF gene in an oversized skin flap increases flap survival and perfusion. In this study, we investigated the potential of magnetofection of magnetic lipospheres containing VEGF165-cDNA on survival and perfusion of ischemic skin flaps and evaluated the method with respect to the significance of applied magnetic field and ultrasound. We prepared perfluoropropane-filled magnetic lipospheres (‘magnetobubbles’) from Tween60-coated magnetic nanoparticles, Metafectene, soybean-oil and cDNA and studied the effect in an oversized random-pattern-flap model in the rats (n= 46). VEGF-cDNA-magnetobubbles were administered under a magnetic field with simultaneously applied ultrasound, under magnetic field alone and with applied ultrasound alone. Therapy was conducted 7 days pre-operative. Flap survival and necrosis were measured 7 days post-operatively. Flap perfusion, VEGF-protein concentration in target and surrounding tissue, formation and appearance of new vessels were analysed additionally. Magnetofection with VEGF-cDNA-magnetobubbles presented an increased flap survival of 50% and increased flap perfusion (P < 0.05). Without ultrasound and without magnetic field, the effect is weakened. VEGF concentration in target tissue was elevated (P < 0.05), while underlying muscle was not affected. Our results demonstrate the successful VEGF gene therapy by means of magnetobubble magnetofection. Here, the method of magnetofection of magnetic lipospheres is equally efficient as adenoviral transduction, but has a presumable superior safety profile. PMID:19040418

  2. Non-viral VEGF(165) gene therapy--magnetofection of acoustically active magnetic lipospheres ('magnetobubbles') increases tissue survival in an oversized skin flap model.

    Science.gov (United States)

    Holzbach, Thomas; Vlaskou, Dialekti; Neshkova, Iva; Konerding, Moritz A; Wörtler, Klaus; Mykhaylyk, Olga; Gänsbacher, Bernd; Machens, H-G; Plank, Christian; Giunta, Riccardo E

    2010-03-01

    Adenoviral transduction of the VEGF gene in an oversized skin flap increases flap survival and perfusion. In this study, we investigated the potential of magnetofection of magnetic lipospheres containing VEGF(165)-cDNA on survival and perfusion of ischemic skin flaps and evaluated the method with respect to the significance of applied magnetic field and ultrasound. We prepared perfluoropropane-filled magnetic lipospheres ('magnetobubbles') from Tween60-coated magnetic nanoparticles, Metafectene, soybean-oil and cDNA and studied the effect in an oversized random-pattern-flap model in the rats (n= 46). VEGF-cDNA-magnetobubbles were administered under a magnetic field with simultaneously applied ultrasound, under magnetic field alone and with applied ultrasound alone. Therapy was conducted 7 days pre-operative. Flap survival and necrosis were measured 7 days post-operatively. Flap perfusion, VEGF-protein concentration in target and surrounding tissue, formation and appearance of new vessels were analysed additionally. Magnetofection with VEGF-cDNA-magnetobubbles presented an increased flap survival of 50% and increased flap perfusion (P < 0.05). Without ultrasound and without magnetic field, the effect is weakened. VEGF concentration in target tissue was elevated (P < 0.05), while underlying muscle was not affected. Our results demonstrate the successful VEGF gene therapy by means of magnetobubble magnetofection. Here, the method of magnetofection of magnetic lipospheres is equally efficient as adenoviral transduction, but has a presumable superior safety profile.

  3. A novel animal model for skin flap prelamination with biomaterials

    Science.gov (United States)

    Zhou, Xianyu; Luo, Xusong; Liu, Fei; Gu, Chuan; Wang, Xi; Yang, Qun; Qian, Yunliang; Yang, Jun

    2016-09-01

    Several animal models of skin flap construction were reported using biomaterials in a way similar to prefabrication. However, there are few animal model using biomaterials similar to prelamination, another main way of clinical skin flap construction that has been proved to be reliable. Can biomaterials be added in skin flap prelamination to reduce the use of autogenous tissues? Beside individual clinical attempts, animal model is needed for randomized controlled trial to objectively evaluate the feasibility and further investigation. Combining human Acellular Dermal Matrix (hADM) and autologous skin graft, we prelaminated flaps based on inguinal fascia. One, two, three and four weeks later, hADM exhibited a sound revascularization and host cell infiltration. Prelaminated skin flaps were then raised and microsurgically transplanted back to groin region. Except for flaps after one week of prelamination, flaps from other subgroups successfully reconstructed defects. After six to sixteen weeks of transplantation, hADM was proved to being able to maintain its original structure, having a wealth of host tissue cells and achieving full revascularization.To our knowledge, this is the first animal model of prelaminating skin flap with biomaterials. Success of this animal model indicates that novel flap prelamination with biomaterials is feasible.

  4. [Case-control study on the iliac bone flap transplantation with deep circumflex iliac artery and quadratus femoris bone flap transplantation for the treatment of Garden III/IV femoral neck fracture of young and middle-aged patients].

    Science.gov (United States)

    Zhang, Xue-quan; Fan, Shi-cai; Li, Hui-jin; Xie, Yan-hua; Luo, Peng-gang

    2015-09-01

    To compare the clinical effects between hip anterior S-P approach combined with iliac bone flap transplantation with deep circumflex iliac artery and posterior K-L approach combined with quadratus femoris bone flap transplantation for the treatment of femoral neck fracture of Garden III-IV in young and middle-aged patients. From January 2004 to January 2011,46 patients with femoral neck fractures were treated by two kinds of operation. Among them, 20 cases were treated with anterior S-P approach combined with iliac bone flap transplantation with deep circumflex iliac artery, included 12 males and 8 females with an average age of (32.1 ± 7.3) years old, involved 12 cases of Garden III and 8 cases of Garden IV. The other 26 cases were treated with posterior K-L approach combined with quadratus femoris bone flap transplantation, included 20 males and 6 females with an average age of (37.8 ± 6.9) years old, involved 16 cases of Garden III and 10 cases of Garden IV. The index of hospitalization (hospitalization time, total cost, operative time, intraoperative blood loss, postoperative complications), the quality index of operation (fracture reduction, position of internal fixation, fracture healing time, nonunion and femoral head necrosis) of two groups were observed and compared. Hip joint function were evaluated by Harris score. All patients were followed up from 28 to 41 months with an average of 36 months. The intraoperative blood loss of group S-P (92.3 ± 10.4) ml was less than that of group K-L (132.4 ± 11.2) ml, there was significant difference between two groups (P fracture healing time of S-P group (83.5 ± 7.3) d was shorter than that of group K-L (103.2 ± 12.6) d, there was significant difference between two groups (P femoral neck fracture of Garden III-IV of young and middle-aged patients, it has characteristics in clear anatomic and easy to operate. As compared with K-L approach, S-P approach can better reserve residual blood supply of femoral neck

  5. Patterns of flap loss related to arterial and venous insufficiency in the rat pedicled TRAM flap.

    Science.gov (United States)

    Qiao, Q; Moon, W; Zhang, F; Chen, S G; Kunda, L; Lineaweaver, W C; Buncke, H J

    1999-08-01

    Vascular supply to the contralateral portion of the conventional transverse rectus abdominis musculocutaneous (TRAM) flap (zone IV) may become compromised, resulting in partial flap loss and requiring segmental excision. The etiology of this necrosis is not clear. This study determines skin necrosis patterns on a superiorly pedicled caudal TRAM flap during conditions of venous and arterial insufficiency, and determines whether cutaneous venous outflow can sustain a flap with venous insufficiency. Twenty-eight adult male Sprague-Dawley rats underwent superior pedicled TRAM flap elevation, and the zones were marked on the skin paddle. The animals were divided into four groups: control (group A, N = 6), arterial ligation (group B, N = 6), venous ligation (group C, N = 8), and venous ligation with cutaneous venous outflow (group D, N = 8). After 10 days, the skin paddle was photographed and the areas of necrotic skin were measured. Results showed that group B (selective arterial ligation) had 51.7 +/- 2.8% and 40.0 +/- 2.0% skin necrosis in zones I and II respectively. Zone I necrosis was significantly greater in group B compared with the control (p < 0.05). Group C (selective venous ligation) resulted in 73.8 +/- 16.4% and 93.8 +/- 33.4% skin necrosis in zones III and IV respectively. This necrosis was significantly greater compared with the control (p < 0.001). Group D rats' lateral skin necrosis compared significantly less with group C (p < 0.001). These results demonstrate that the patterns of flap necrosis in rat TRAM flaps with poor arterial inflow differ from those with venous stasis. Necrosis of the contralateral portion (zone IV) of human TRAM flaps may be related to problems with venous stasis; thus, a cutaneous venous outflow may prevent this problem.

  6. Towards an industrial manufactured morphing trailing edge flap system for wind turbines

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Løgstrup Andersen, Tom; Bergami, Leonardo

    2014-01-01

    Industri (DK) work on flap manufacturing and Hydratech Industries (DK) is developing the powering system for the flaps and the control system. DTU is the coordinator of the project. Flap prototypes have been manufactured in a continuous thermoplastic extrusion process and a unique rotating test rig has...

  7. COLIBRI : A hovering flapping twin-wing robot

    NARCIS (Netherlands)

    Roshanbin, A.; Altartouri, H.; Karasek, M.; Preumont, André

    2017-01-01

    This paper describes the results of a six-year project aiming at designing and constructing a flapping twin-wing robot of the size of hummingbird (Colibri in French) capable of hovering. Our prototype has a total mass of 22 g, a wing span of 21 cm and a flapping frequency of 22 Hz; it is actively

  8. Reduction of Helicopter Blade-Vortex Interaction Noise by Active Rotor Control Technology

    Science.gov (United States)

    Yu, Yung H.; Gmelin, Bernd; Splettstoesser, Wolf; Brooks, Thomas F.; Philippe, Jean J.; Prieur, Jean

    1997-01-01

    Helicopter blade-vortex interaction noise is one of the most severe noise sources and is very important both in community annoyance and military detection. Research over the decades has substantially improved basic physical understanding of the mechanisms generating rotor blade-vortex interaction noise and also of controlling techniques, particularly using active rotor control technology. This paper reviews active rotor control techniques currently available for rotor blade vortex interaction noise reduction, including higher harmonic pitch control, individual blade control, and on-blade control technologies. Basic physical mechanisms of each active control technique are reviewed in terms of noise reduction mechanism and controlling aerodynamic or structural parameters of a blade. Active rotor control techniques using smart structures/materials are discussed, including distributed smart actuators to induce local torsional or flapping deformations, Published by Elsevier Science Ltd.

  9. [Modified sternocleidomastoid myocutaneous flap for reconstruction of soft tissue defects following tumorectomy of maxillofacial region].

    Science.gov (United States)

    Lin, Yi; Zhu, Huiyong; Liu, Jianhua; Wang, Huiming

    2010-04-01

    To investigate clinical effect and prognosis of the modified sternocleidomastoid (MSCM) myocutaneous flap for reconstruction of tissue defects in patients with oral carcinomas undergoing tumorectomy. From April 2001 to January 2007, 43 patients with large or medium-sized tissue defects because of oral carcinomas radical operation were treated with MSCM myocutaneous flap. There were 31 males and 12 females with an average age of 58.5 years (25-76 years). The disease course was 25 days to 14 months (4.5 months on average). There were 27 cases of well-differentiated squamous cell carcinoma (SC), 14 cases of poorly-differentiated SC, 1 case of rhabdomyosarcoma, and 1 case of adenoid cystic carcinoma. Affected locations were tongue in 25 cases, mouth floor in 11 cases, lower gingiva in 4 cases, and buccal mucous membranes in 3 cases. According to 2002 International Union Control Cancer criterion for clinical stage, there were 3 cases of stage I, 13 cases of stage II, 7 cases of stage III, and 20 cases of stage IV. Both the ranges of soft tissue defects and the flap were from 4 cm x 3 cm to 8 cm x 6 cm. The vitality of the flaps and the healing of wounds were observed postoperatively. The function restoration of deglutition and dehisce were observed during the follow-up period. Necrosis of quarter MSCM myocutaneous flap occurred in 3 cases 1 week after operation, wounds healed by secondary intention after dressing; other flaps were survival. Infection with fluidity occurred at the donor site of 2 cases, wounds healed by incision and drainage; other incision at the donor sites healed primarily. No arterial or venous crisis occurred in all 43 flaps after 48 hours of operation. Thirty-nine patients were followed up for 6 months to 6 years. The 3 patients with buccal carcinoma could open their mouths normally. The function of deglutition and pronunciation were recovered in 24 patients with tongue carcinoma. Only 3 patients needed to have soft diet after operation. In 26

  10. Flap double twist technique for prevention of LASIK flap striae

    Directory of Open Access Journals (Sweden)

    Nabil KM

    2016-11-01

    Full Text Available Karim Mahmoud Nabil Department of Ophthalmology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt Abstract: A novel flap double twist technique was applied to reduce the incidence of post-laser-assisted in situ keratomileusis (LASIK flap striae. The flap is floated and stroked in the same way as is done for management of first postoperative day striae, where the method is to float and irrigate the flap into position, followed by applying gentle pressure on the flap with a wet Merocel microsponge and moving the flap away from the hinge position. The sponge is then manually squeezed to become drier, and the flap is continuously stroked in a direction opposite to the hinge. Next, the flap is carefully twisted obliquely and sequentially in two opposite directions while applying gentle pressure on the flap in order to completely dehydrate the flap and stromal bed. Finally, the flap is repositioned while applying gentle horizontal pressure in two opposite directions. This novel flap double twist technique shows great success in post-LASIK striae prevention. Keywords: laser-assisted in situ keratomileusis, wrinkles, pressure, microsponge

  11. Corrigendum to: Discussion on "Active aeroelastic control of 2-D wing-flap systems operating in an incompressible flowfield and impacted by a blast pulse" by Librescu et al., Journal of Sound and Vibration 283 (3-5) (2005) 685-706 [Journal of Sound Vibration 332 (13) (2013) 3351-3358

    Science.gov (United States)

    Mozaffari-Jovin, S.; Firouz-Abadi, R. D.; Roshanian, J.; Ghaffari, A.

    2014-12-01

    This corrigendum supplies a corrected statement of an equation in our discussion paper recently appearing in Journal of Sound and Vibration 332 (13) (2013) 3351-3358. This equation concerns the control input coefficient matrix of the state-space representation of the aeroelastic system. It illustrates the influence of the error in the calculation of aeroelastic impulse, step, and ramp responses, as well as demonstrating the accuracy and legitimacy of the present model in comparison to well-established literature data.

  12. Coronally advanced flap + connective tissue graft techniques for the treatment of deep gingival recession in the lower incisors. A controlled randomized clinical trial.

    Science.gov (United States)

    Zucchelli, Giovanni; Marzadori, Matteo; Mounssif, Ilham; Mazzotti, Claudio; Stefanini, Martina

    2014-08-01

    The aim of this study was to compare the clinical and aesthetic outcomes of two different surgical approaches for the treatment of deep gingival recession affecting the mandibular incisors. Fifty patients with Miller class I and II gingival recessions (≥ 3 mm) in the lower incisors were enrolled. Twenty-five patients were randomly assigned to the control group and the other 25 patients to the test group. All defects were treated with the coronally advanced flap + connective tissue graft (CAF + CTG) and in the test group the labial submucosal tissue (LST) was removed. Post-operative morbidity was evaluated at 1 week. Clinical and aesthetic evaluations were made at 1 year. Statistically greater recession reduction, probability of CRC (adjusted OR 7.94 95% CI = 1.88-33.50, p = 0.0024) and greater increase in GT were observed in the test group. Greater graft exposure and increase in KTH were demonstrated in the control group. Better aesthetics outcomes were observed in the test group. No statistically significant between groups differences were demonstrated in patient analgesic assumption and post-operative discomfort and bleeding. LST removal during CAF + CTG surgery is indicated to provide better root coverage and aesthetic outcomes in the treatment of gingival recessions affecting the lower incisors. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Active control of convection

    Energy Technology Data Exchange (ETDEWEB)

    Bau, H.H. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    1995-12-31

    Using stability theory, numerical simulations, and in some instances experiments, it is demonstrated that the critical Rayleigh number for the bifurcation (1) from the no-motion (conduction) state to the motion state and (2) from time-independent convection to time-dependent, oscillatory convection in the thermal convection loop and Rayleigh-Benard problems can be significantly increased or decreased. This is accomplished through the use of a feedback controller effectuating small perturbations in the boundary data. The controller consists of sensors which detect deviations in the fluid`s temperature from the motionless, conductive values and then direct actuators to respond to these deviations in such a way as to suppress the naturally occurring flow instabilities. Actuators which modify the boundary`s temperature/heat flux are considered. The feedback controller can also be used to control flow patterns and generate complex dynamic behavior at relatively low Rayleigh numbers.

  14. Non-viral VEGF(165) gene therapy--magnetofection of acoustically active magnetic lipospheres ('magnetobubbles') increases tissue survival in an oversized skin flap model

    National Research Council Canada - National Science Library

    Holzbach, Thomas; Vlaskou, Dialekti; Neshkova, Iva; Konerding, Moritz A; Wörtler, Klaus; Mykhaylyk, Olga; Gänsbacher, Bernd; Machens, H-G; Plank, Christian; Giunta, Riccardo E

    2010-01-01

    .... We prepared perfluoropropane-filled magnetic lipospheres ('magnetobubbles') from Tween60-coated magnetic nanoparticles, Metafectene, soybean-oil and cDNA and studied the effect in an oversized random-pattern-flap model in the rats (n= 46...

  15. Smart Rotor Modeling: Aero-Servo-Elastic Modeling of a Smart Rotor with Adaptive Trailing Edge Flaps

    DEFF Research Database (Denmark)

    Bergami, Leonardo

    This book presents the formulation of an aero-servo-elastic model for a wind turbine rotor equipped with Adaptive Trailing Edge Flaps (ATEF), a smart rotor configuration. As the name suggests, an aero-servo-elastic model consists of three main components: an aerodynamic model, a structural model......, and a control model. The book first presents an engineering type of aerodynamic model that accounts for the dynamic effects of flap deflection. The aerodynamic model is implemented in a Blade Element Momentum framework, and coupled with a multi-body structural model in the aero-servoelastic simulation code HAWC...... the trailing edge flap deflection to actively reduce the fatigue loads on the structure. The performance of the smart rotor configuration and its control algorithms are finally quantified by aero-servo-elastic simulations of the smart rotor turbine operating in a standard turbulent wind field....

  16. Active Combustion Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past decade, research into active combustion control has yielded impressive results in suppressing thermoacoustic instabilities and widening the operational...

  17. An analysis of free flap failure using the ACS NSQIP database. Does flap site and flap type matter?

    Science.gov (United States)

    Kwok, Alvin C; Agarwal, Jayant P

    2017-09-01

    We sought to use the NSQIP database to determine the national rate and predictors of free flap failure based upon flap sites and flap types. Free flaps were identified using the 2005-2010 NSQIP database. We examined overall flap failure rates as well as failure rates based upon flap sites (head and neck, extremities, trunk, and breast) and flap types (muscle, fascial, skin, bone, and bowel flaps). Univariate and multivariate analyses were used to determine predictors of flap failure. There were 1,187 microvascular free tissue transfers identified. The overall flap failure rate was 5.1%. Head and neck flaps had the highest rate of free flap failure at 7.7%. Prolonged operative time is an independent predictor of flap failure for all free flaps (OR: 2.383, P = 0.0013). When examining predictors of failure by flap site, free flaps to the breast with prolonged operative time are independently associated with flap failure (OR: 2.288, P = 0.0152). When examining predictors of flap failure by flap type, muscle based free flaps with an ASA classification ≥3 are associated with flap failure (P = 0.0441). Risk factors for free flap failure differ based upon flap site and flap type. Prolonged operative time is an independent risk factor for the failure of free flaps used for breast reconstruction. An ASA classification ≥3 is associated with the failure of free muscle based flaps. Our findings identify actionable areas that may help to improve free flap success. © 2016 Wiley Periodicals, Inc.

  18. Long-term evaluation of donor-site morbidity after radial forearm flap phalloplasty for transsexual men.

    Science.gov (United States)

    Van Caenegem, Eva; Verhaeghe, Evelien; Taes, Youri; Wierckx, Katrien; Toye, Kaatje; Goemaere, Stefan; Zmierczak, Hans-Georg; Hoebeke, Piet; Monstrey, Stan; T'Sjoen, Guy

    2013-06-01

    Phalloplasty using the radial forearm flap is currently the most frequently used technique to create the neophallus in transsexual men (formerly described as female-to-male transsexual persons). Although it is considered the gold standard, its main disadvantage is the eventual donor-site morbidity in a young, healthy patient population. The study aims to examine the long-term effects of radial forearm flap phalloplasty in transsexual men and to evaluate aesthetic outcome, scar acceptance, bone health, and daily functioning. Scars were evaluated with the patient and observer scar assessment scale, the Vancouver Scar Scale, and self-reported satisfaction. Bone health was assessed using dual X-ray absorptiometry and peripheral quantitative computed tomography, and daily functioning using a physical activity questionnaire (Baecke). These measurements were compared with 44 age-matched control women. This is a cross-sectional study of 44 transsexual, a median of 7 years after radial forearm flap phalloplasty, recruited from the Center for Sexology and Gender Problems at the Ghent University Hospital, Belgium. We observed no functional limitations on daily life activities, a pain-free and rather aesthetic scar, and unaffected bone health a median of 7 years after radial foreram flap phalloplasty. Over 75% of transsexual men were either satisfied or neutral with the appearance of the scar. Transsexual men, despite scarring the forearm, consider the radial forearm flap phalloplasty as worthwhile. © 2013 International Society for Sexual Medicine.

  19. The effect of atorvastatin on survival of rat ischemic flap

    Directory of Open Access Journals (Sweden)

    Jian-Xun Chen

    2013-04-01

    Full Text Available Management of skin avulsion with tissue exposure is a challenge for plastic surgeons. Clinical observations have suggested that longer survival of skin flap prevents further contamination and infection. Less well known is the role of atorvastatin in avulsion skin flap. Therefore, we attempted to determine whether atorvastatin could alleviate avulsion skin flap in a rat model. Twenty male Sprague–Dawley rats were randomized into two groups: the atorvastatin group and the control. Before operation, each rat received an initial blood perfusion scan as baseline data. Then, each rat received an operation of skin flap incision, elevation, and resuturing to the original position under general anesthesia. Another blood perfusion scan was performed on each rat 30 minutes, 4 days, and 7 days postoperatively. On the 7th postoperative day, the necrotic area of skin flap was measured as the skin flap viability. The skin flap tissues at 2.5 and 5 cm distal to the skin flap base were collected for histopathological analysis, as well as measurement of vascular endothelial growth factor (VEGF mRNA expression, and vascular density. Compared with 30 minutes postoperation, there was a significant increase in the ratio of skin flap blood perfusion on the 4th and 7th days postoperation in both control and atorvastatin groups (p<0.05. Compared with the control group, there was a significant decrease in necrotic area, significant increase in ratio of skin flap blood perfusion on postoperation days 4 and 7, and significant increase in vascular density under high field at 2.5 cm distal to the base of skin flap in the atorvastatin group (p<0.05. The VEGF121 and VEGF165 mRNA expression at 2.5 cm distal to the base of skin flap differed significantly between the two groups (p<0.05. Compared with the control group, atorvastatin treatment improved skin flap blood perfusion, vascular density, and necrotic area dependent on VEGF mRNA expression.

  20. Automaticity or active control

    DEFF Research Database (Denmark)

    Tudoran, Ana Alina; Olsen, Svein Ottar

    aspects of the construct, such as routine, inertia, automaticity, or very little conscious deliberation. The data consist of 2962 consumers participating in a large European survey. The results show that habit strength significantly moderates the association between satisfaction and action loyalty, and......, respectively, between intended loyalty and action loyalty. At high levels of habit strength, consumers are more likely to free up cognitive resources and incline the balance from controlled to routine and automatic-like responses....

  1. Coronally advanced flap versus the pouch technique combined with a connective tissue graft to treat Miller's class I gingival recession: a randomized controlled trial.

    Science.gov (United States)

    Salhi, Leila; Lecloux, Geoffrey; Seidel, Laurence; Rompen, Eric; Lambert, France

    2014-04-01

    The objective of this study was to compare two different periodontal plastic surgery procedures to treat Miller's class I recession: a coronally advanced flap(control group) versus the pouch technique (test group), both of which were associated with connective tissue graft. Forty consecutive patients were included, with 20 patients being allocated for each group. The level of recession coverage, the keratinized tissue (KT)quantity, gingival aesthetics (PES) and post-operative outcomes were assessed for a follow-up period of 6 months. After 6 months, both techniques allowed for the excellent mean root coverage of 96.3 plus/minus 12.1% in the control group and of 91.3 plus/minus 17.6% in the test group.Complete root coverage was achieved in 89.5% (17/19) and 79% (15/19) of the recession cases in the control and the test groups respectively. A significant increase in KT height (p = 0.0011) was observed in the test group. A significant improvement in the pink aesthetic score was found in the two groups, but gingival texture displayed significantly better results in the test group (p < 0.0001). No significant difference between the two groups was found in terms of the morbidity outcomes. Pain killer consumption was similar in the two groups and significantly decreased over time. Both surgical techniques are relevant in treating Miller's class I recession. The pouch technique seems to increase the height of KT better and provides good gingival-related aesthetic outcomes.

  2. Application analysis on different suture of scleral flap in trabeculectomy

    Directory of Open Access Journals (Sweden)

    Ning Liu

    2014-05-01

    Full Text Available AIM: To research the application of scleral flap suture in trabeculectomy. METHODS: Totally 114 primary angle-closure glaucoma patients, aged from 36-72 years old, were selected as the objects, and randomly divided into research group and control group. The two groups received different administration methods. Traditional sewing method of sclera flap was used in research group and improved sewing method of sclera flap was used in control group. RESULTS: There was statistical differences between postoperative intraocular pressure of the patients in the observation group and the control group after 1d; 2wk; 1, 3mo(PPP>0.05.CONCLUSION: It is safe and effective that the improved sewing method of sclera flap for trabeculectomy of acute angle-closure glaucoma, and it is a better method to avoid the occurrence of shallow anterior chamber than the traditional sewing method in the early stage after operation.

  3. Vascular complications and microvascular free flap salvage: the role of thrombolytic agents.

    Science.gov (United States)

    Chang, Eric I; Mehrara, Babak J; Festekjian, Jaco H; Da Lio, Andrew L; Crisera, Christopher A

    2011-10-01

    Vascular thrombosis with flap loss is the most dreaded complication of microvascular free tissue transfer. Thrombolytic agents such as tissue plasminogen activator have been used clinically for free flap salvage in cases of pedicle thrombosis. Yet, there is a paucity of data in the literature validating the benefit of their use. A retrospective review of the breast reconstruction free flap database was performed at a single institution between the years of 1991-2010. The incidence of vascular complications (arterial and/or venous thrombosis) was examined to determine the role of adjuvant thrombolytic therapy in flap salvage. Pathologic examination was used to determine the incidence of fat necrosis after secondary revision procedures. Seventy-four cases were identified during the study period. In 41 cases, revision of the anastamoses was performed alone without thrombolytics with 38 cases of successful flap salvage (92.7%). In 33 cases, anastamotic revision was performed with adjuvant thrombolytic therapy, and successful flap salvage occurred in 28 of these cases (84.8%). Thrombolysis did not appear to significantly affect flap salvage. Interestingly, only two of the salvaged flaps that had received thrombolysis developed fat necrosis, whereas 11 of the nonthrombolysed flaps developed some amount fat necrosis (7.1% vs. 28.9%, P dissolution of thrombi in the microvasculature with the administration of thrombolytics. Although the use of adjuvant thrombolytic therapy does not appear to impact the rate of flap salvage, their use may have secondary benefits on overall flap outcomes. Copyright © 2011 Wiley-Liss, Inc.

  4. Computational Aerodynamics of Insects' Flapping Flight

    Science.gov (United States)

    Yang, Kyung Dong; Kyung, Richard

    2011-11-01

    The kinematics of the Insects' flapping flight is modeled through mathematical and computational observations with commercial software. Recently, study on the insects' flapping flight became one of the challenging research subjects in the field of aeronautics because of its potential applicability to intelligent micro-robots capable of autonomous flight and the next generation aerial-vehicles. In order to uncover its curious unsteady characteristics, many researchers have conducted experimental and computational studies on the unsteady aerodynamics of insects' flapping flight. In the present paper, the unsteady flow physics around insect wings is carried out by utilizing computer software e-AIRS. The e-AIRS (e-Science Aerospace Integrated Research System) analyzes and models the results of computational and experimental aerodynamics, along with integrated research process of these two research activities. Stroke angles and phase angles, the important two factors in producing lift of the airfoils are set as main parameters to determine aerodynamic characteristics of the insects' flapping flight. As a result, the optimal phase angle to minimize the drag and to maximize the lift are found. Various simulations indicate that using proper value of variables produce greater thrust due to an optimal angle of attack at the initial position during down stroke motion.

  5. Sizing and Control of Trailing Edge Flaps on a Smart Rotor for Maximum Power Generation in Low Fatigue Wind Regimes

    DEFF Research Database (Denmark)

    Smit, Jeroen; Berghammer, Lars O.; Navalkar, Sachin

    2014-01-01

    In this paper an extension of the spectrum of applicability of rotors with active aerody-namic devices is presented. Besides the classical purpose of load alleviation, a secondary objective is established: power capture optimization. As a _rst step, wind speed regions that contribute little...

  6. Sizing and control of trailing edge flaps on a smart rotor for maximum power generation in low fatigue wind regimes

    DEFF Research Database (Denmark)

    Smit, Jeroen; Bernhammer, Lars O.; Navalkar, Sachin T.

    2016-01-01

    An extension of the spectrum of applicability of rotors with active aerodynamic devices is presented in this paper. Besides the classical purpose of load alleviation, a secondary objective is established: optimization of power capture. As a first step, wind speed regions that contribute little...

  7. Prevention of Oral Candidiasis After Free Flap Surgery: Role of 3% Sodium Bicarbonate Saline in Oral Care.

    Science.gov (United States)

    Yang, Yue; Zhang, Fang; Lyu, Xin; Yan, Zhimin; Hua, Hong; Peng, Xin

    2017-03-01

    Relevant reports about oral candidiasis status and prevention measures after free flap surgery for the oral and maxillofacial region are limited. The present study explored oral candidiasis status after free flap surgery and its prevention through a prospective comparative study. One hundred four patients were randomized to a control group (n = 54) and an experimental group (n = 50). Compared with the control group, the experimental group was provided an additional 3% sodium bicarbonate saline solution for oral care after free flap surgery. The incidence of oral candidiasis was evaluated by objective examination (saliva culture and salivary pH measurement) and subjective evaluation (clinical signs of oral candidiasis) at admission and from postoperative days 1 to 14. The salivary pH values of the 2 groups were lower than the normal salivary pH, and postoperative salivary pH values were always lower than the active range of oral lysozymes in the control group. The salivary pH values of the experimental group were higher than those of the control group from postoperative days 6 to 14 (P candidiasis was 13.0% in the control group, which was higher than that in the experimental group (2.0%; P candidiasis. Oral candidiasis was common in patients after free flap reconstruction surgery, and the use of 3% sodium bicarbonate saline solution for oral care effectively prevented it. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  8. A dissolved oxygen dressing: a pilot study in an ischemic skin flap model.

    Science.gov (United States)

    Zellner, Susan; Manabat, Rowena; Roe, David F

    2015-02-01

    To determine if skin flap failure rates could be improved with the use of a dissolved oxygen wound dressing in a porcine model. Full-thickness skin flaps (4 × 16 cm) were raised on pigs. Flaps were randomly assigned after surgery to experimental treatment with a dissolved oxygen dressing (treatment group) or a hydrogel dressing (control group). Flaps were evaluated daily for 14 days. Skin flaps that failed any one of four key clinical outcomes were considered failures. Histological parameters (including skin and subcutaneous necrosis, inflammation, ischemia, fibrosis, and bacterial load) were compared by a blinded histopathologist. Sixteen full-thickness skin flaps were raised on four pigs. All animals survived surgery and all incisions were evaluable. Clinical flap failure was observed in six (75%) control-treated wounds and in two (25%) dissolved oxygen-treated wounds. Histological evaluation demonstrated no significant differences in the proximal 75% of the flaps. There were significant differences in a number of histological parameters in the distal 25% in favor of the dissolved oxygen dressing. Flaps treated with a dissolved oxygen dressing had fewer clinical failures and improved histological profiles compared with control-treated flaps, suggesting that increasing local oxygen supply may improve the local wound healing environment. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  9. Airbag-induced corneal flap.

    Science.gov (United States)

    Liyanage, Sidath E; Mearza, Ali A

    2009-02-01

    To describe a case of airbag-induced corneal flap in a previously normal cornea. Case report. A 27-year-old woman presented with complete loss of vision in her left eye following a road traffic accident which involved airbag deployment. There was no previous ocular history. Examination revealed a large corneal flap of 6mm in diameter, extending to the depth of anterior stroma. This was accompanied by a traumatic optic neuropathy. One month follow-up revealed complete reattachment of the corneal flap. This is the first reported case of a corneal flap induced by airbag deployment in a cornea with previously normal architecture.

  10. Effects of Sanguis Draconis on Perforator Flap Survival in Rats

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2016-09-01

    Full Text Available Sanguis draconis, a resin known to improve blood circulation, relieve pain, stimulate tissue regeneration, and heal wounds, is widely used in clinical practice. In this study, we prepared an ethanol extract of sanguis draconis (EESD containing 75.08 mg/g of dracorhodin. The experiment was carried out on 20 rats that were divided into two groups, a control group (n = 10 and an EESD group (n = 10. All the rats underwent a perforator flap surgery, after which post-operative abdominal compressions of EESD were given to the EESD group for seven days, while the control group received saline. Flap survival percentages were determined after seven days, and were found to be significantly higher in the EESD group than in the control group. Results of laser Doppler flowmetry (LDF showed that perforator flaps in the EESD group had higher perfusion values than those of the control group. The flap tissues were stained with hematoxylin and eosin, followed by immunohistochemical evaluation. Superoxide dismutase (SOD expression and micro-vessel development markedly increased in the EESD group, while malondialdehyde (MDA levels decreased. This is the first study to investigate the effect of sanguis draconis on perforator flap survival. Our results demonstrate that sanguis draconis can improve perforator flap survival in rats by promoting microvessel regeneration and blood perfusion.

  11. Effects of Sanguis Draconis on Perforator Flap Survival in Rats.

    Science.gov (United States)

    Zhang, Yang; Cai, Xiaobing; Shen, Lifeng; Huang, Xiaowen; Wang, Xuping; Lan, Yinan; Shou, Dan

    2016-09-26

    Sanguis draconis, a resin known to improve blood circulation, relieve pain, stimulate tissue regeneration, and heal wounds, is widely used in clinical practice. In this study, we prepared an ethanol extract of sanguis draconis (EESD) containing 75.08 mg/g of dracorhodin. The experiment was carried out on 20 rats that were divided into two groups, a control group (n = 10) and an EESD group (n = 10). All the rats underwent a perforator flap surgery, after which post-operative abdominal compressions of EESD were given to the EESD group for seven days, while the control group received saline. Flap survival percentages were determined after seven days, and were found to be significantly higher in the EESD group than in the control group. Results of laser Doppler flowmetry (LDF) showed that perforator flaps in the EESD group had higher perfusion values than those of the control group. The flap tissues were stained with hematoxylin and eosin, followed by immunohistochemical evaluation. Superoxide dismutase (SOD) expression and micro-vessel development markedly increased in the EESD group, while malondialdehyde (MDA) levels decreased. This is the first study to investigate the effect of sanguis draconis on perforator flap survival. Our results demonstrate that sanguis draconis can improve perforator flap survival in rats by promoting microvessel regeneration and blood perfusion.

  12. Active control: Wind turbine model

    DEFF Research Database (Denmark)

    Bindner, H.

    1999-01-01

    This report is a part of the reporting of the work done in the project 'Active Control of Wind Turbines'. This project aim is to develop a simulation model for design of control systems for turbines with pitch control and to use that model to designcontrollers. This report describes the model...... developed for controller design and analysis. Emphasis has been put on establishment of simple models describing the dynamic behavior of the wind turbine in adequate details for controller design. This hasbeen done with extensive use of measurements as the basis for selection of model complexity and model....... The models are all formulated as linear differential equations. The models are validated throughcomparisons with measurements performed on a Vestas WD 34 400 kW wind turbine. It is shown from a control point of view simple linear models can be used to describe the dynamic behavior of a pitch controlled wind...

  13. Optical control of antibacterial activity.

    Science.gov (United States)

    Velema, Willem A; van der Berg, Jan Pieter; Hansen, Mickel J; Szymanski, Wiktor; Driessen, Arnold J M; Feringa, Ben L

    2013-11-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a 'smart' antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism. 

  14. Endoscopic grading of the gastroesophageal flap valve is correlated with reflux activity and can predict the size of the esophageal hiatus in patients with gastroesophageal reflux disease.

    Science.gov (United States)

    Koch, Oliver Owen; Spaun, Georg; Antoniou, Stavros A; Rabl, Charlotte; Köhler, Gernot; Emmanuel, Klaus; Öfner, Dietmar; Pointner, Rudolph

    2013-12-01

    Endoscopic grading of the gastroesophageal flap valve (GEFV) is simple, reproducible, and suggested to be a good predictor of reflux activity. This study aimed to investigate the potential correlation between grading of the GEFV and quality of life (QoL), gastroesophageal reflux disease (GERD) symptoms, esophageal manometry, multichannel intraluminal impedance monitoring (MII) data, and size of the hiatal defect. The study included 43 patients with documented chronic GERD who underwent upper gastrointestinal endoscopy, esophageal manometry, and ambulatory MII monitoring before laparoscopic fundoplication. The GEFV was graded 1-4 using Hill's classification. QoL was evaluated using the Gastrointestinal Quality-of-Life Index (GIQLI), and gastrointestinal symptoms were documented using a standardized questionnaire. The size of the esophageal hiatus was measured during surgery by calculating the hiatal surface area (HSA). Analysis of the correlation between QoL, GERD symptoms, esophageal manometry, MII data, HSA size, and GEFV grading was performed. Statistical significance was set at a p value of 0.05. A significant positive correlation was found between increased GEFV grade and DeMeester score, total number of acid reflux events, number of reflux events in the supine position, and number of reflux events in the upright position. Additionally, a significant positive correlation was found between HSA size and GEFV grading. No significant influence from intensity of GERD symptoms, QoL, and the GEFV grading was found. The mean LES pressures were reduced with increased GEFV grade, but not significantly. The GEFV plays a major role in the pathophysiology of GERD. The results underscore the importance of reconstructing a valve in patients with GERD and an altered geometry of the gastroesophageal junction when they receive a laparoscopic or endoscopic intervention.

  15. Papilla Preservation Flap as Aesthetic Consideration in Periodontal Flap Surgery

    Directory of Open Access Journals (Sweden)

    Sandra Olivia

    2013-07-01

    Full Text Available Flap surgery is treatment for periodontal disease with alveolar bone destruction. Surgical periodontal flap with conventional incision will result in gingival recession and loss of interdental papillae after treatment. Dilemma arises in areas required high aesthetic value or regions with a fixed denture. It is challenging to perform periodontal flap with good aesthetic results and minimal gingival recession. This case report aimed to inform and to explain the work procedures, clinical and radiographic outcomes of surgical papilla preservation flap in the area that requires aesthetic. Case 1 was a surgical incision flap with preservation of papillae on the anterior region of teeth 11 and 12, with a full veneer crown on tooth 12. Case 2 was a surgical incision flap with preservation of papillae on the posterior region of tooth 46 with inlay restoration. Evaluation for both cases were obtained by incision papilla preservation of primary closure was perfect, good aesthetic results, minimal gingival recession and the interdental papillae can be maintained properly. In conclusion, periodontal flap surgery on the anterior region or regions that require high aesthetic value could be addressed with papilla preservation incision. Incision papilla preservation should be the primary consideration in periodontal flap surgery if possible.DOI: 10.14693/jdi.v19i3.144

  16. Active Flow Control Activities at NASA Langley

    Science.gov (United States)

    Anders, Scott G.; Sellers, William L., III; Washburn, Anthony E.

    2004-01-01

    NASA Langley continues to aggressively investigate the potential advantages of active flow control over more traditional aerodynamic techniques. This paper provides an update to a previous paper and describes both the progress in the various research areas and the significant changes in the NASA research programs. The goals of the topics presented are focused on advancing the state of knowledge and understanding of controllable fundamental mechanisms in fluids as well as to address engineering challenges. An organizational view of current research activities at NASA Langley in active flow control as supported by several projects is presented. On-center research as well as NASA Langley funded contracts and grants are discussed at a relatively high level. The products of this research are to be demonstrated either in bench-top experiments, wind-tunnel investigations, or in flight as part of the fundamental NASA R&D program and then transferred to more applied research programs within NASA, DOD, and U.S. industry.

  17. Demonstration of Active Combustion Control

    Science.gov (United States)

    Lovett, Jeffrey A.; Teerlinck, Karen A.; Cohen, Jeffrey M.

    2008-01-01

    The primary objective of this effort was to demonstrate active control of combustion instabilities in a direct-injection gas turbine combustor that accurately simulates engine operating conditions and reproduces an engine-type instability. This report documents the second phase of a two-phase effort. The first phase involved the analysis of an instability observed in a developmental aeroengine and the design of a single-nozzle test rig to replicate that phenomenon. This was successfully completed in 2001 and is documented in the Phase I report. This second phase was directed toward demonstration of active control strategies to mitigate this instability and thereby demonstrate the viability of active control for aircraft engine combustors. This involved development of high-speed actuator technology, testing and analysis of how the actuation system was integrated with the combustion system, control algorithm development, and demonstration testing in the single-nozzle test rig. A 30 percent reduction in the amplitude of the high-frequency (570 Hz) instability was achieved using actuation systems and control algorithms developed within this effort. Even larger reductions were shown with a low-frequency (270 Hz) instability. This represents a unique achievement in the development and practical demonstration of active combustion control systems for gas turbine applications.

  18. Effects of Rosmarinus officinalis on the survivability of random-patterned skin flaps: an experimental study.

    Science.gov (United States)

    Ince, Bilsev; Yildirim, Alpagan Mustafa; Okur, Mehmet Ihsan; Dadaci, Mehmet; Yoruk, Ebru

    2015-04-01

    Improving survival of skin flaps used in soft-tissue reconstruction is clinically an important goal, and several systemic and local agents have been used for this purpose. However, a substance that prevents the flap necrosis has not yet been defined. This study aimed to investigate whether a Rosmarinus officinalis extract could improve the skin flap survival. In this study, 21 Wistar albino rats were divided into three groups. Rectangular 8 × 2 cm random-pattern flaps were elevated from the back of the rats. Group I was considered the control group. In Group II, a 0.5-cc of Rosmarinus officinalis oil was applied with an ear bud to the flap area 30 minutes before the flap elevation. After suturing the flaps to their location, the oil was administered twice a day for a week. In Group III, 0.5 cc of the oil was applied twice a day to the area that was elevated for a week until surgery. At the end of the week, the flaps were sutured to their location, and wiped postoperatively twice a day for a week with the oil. Mean percentage of these areas was found to be 29.81%, 58.99%, and 67.68% in Group I, Group II, and Group III, respectively. The mean percentage of the flap survival areas and vessel diameters were significantly greater in the Groups II and III than in the control group (p Rosmarinus officinalis extract can increase the flap survivability.

  19. A high voltage DC-DC converter driving a Dielectric Electro Active Polymer actuator for wind turbine flaps

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.

    2012-01-01

    The Dielectric Electro Active Polymer (DEAP) material is a very thin (~80 μm) silicone elastomer film with a compliant metallic electrode layer on both sides. The DEAP is fundamentally a capacitor that is capable of very high strain. The property that the polymer changes its shape, as a result...

  20. Active Control of Stationary Vortices

    Science.gov (United States)

    Nino, Giovanni; Breidenthal, Robert; Bhide, Aditi; Sridhar, Aditya

    2016-11-01

    A system for active stationary vortex control is presented. The system uses a combination of plasma actuators, pressure sensors and electrical circuits deposited on aerodynamic surfaces using printing electronics methods. Once the pressure sensors sense a change on the intensity or on the position of the stationary vortices, its associated controller activates a set of plasma actuator to return the vortices to their original or intended positions. The forces produced by the actuators act on the secondary flow in the transverse plane, where velocities are much less than in the streamwise direction. As a demonstration case, the active vortex control system is mounted on a flat plate under low speed wind tunnel testing. Here, a set of vortex generators are used to generate the stationary vortices and the plasma actuators are used to move them. Preliminary results from the experiments are presented and compared with theoretical values. Thanks to the USAF AFOSR STTR support under contract # FA9550-15-C-0007.

  1. Innervated digital artery perforator flap.

    Science.gov (United States)

    Ozcanli, Haluk; Coskunfirat, Osman Koray; Bektas, Gamze; Cavit, Ali

    2013-02-01

    To describe a technique for covering defects of the fingertips: the innervated digital artery perforator (IDAP) flap. A total of 17 patients were treated with an IDAP flap. The size of the flaps varied between 2 ×1 cm and 3.5 × 2 cm. Postoperative evaluation of the patients consisted of the Semmes-Weinstein Monofilament test, static 2-point discrimination, patient satisfaction, extension loss, and an investigation into complications. All IDAP flaps survived completely, and no patients required secondary interventions. The mean follow-up period was 7 months (range, 6-10 mo). The Semmes-Weinstein monofilament test results ranged from 3.22 to 3.84. The static 2-point discrimination in the flaps ranged from 2 mm to 4 mm (mean, 3.4 mm) compared with a range of 2 mm to 3 mm (mean, 2.7 mm) on the contralateral hand. There were no joint contractures in the reconstructed fingertips, although 2 patients developed mild hook nail deformity. One patient experienced mild cold intolerance, and 1 patient exhibited mild postoperative hypersensitivity. The advantages of the IDAP flap include minimally invasive surgery; a reliable, versatile flap; and the ease of the technique for different-sized fingertip defect reconstructions with few complications. The IDAP flap may be useful in fingertip amputations when the amputated part is not suitable for replantation. Therapeutic IV. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  2. Modeling of Airfoil Trailing Edge Flap with Immersed Boundary Method

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2011-01-01

    The present work considers incompressible flow over a 2D airfoil with a deformable trailing edge. The aerodynamic characteristics of an airfoil with a trailing edge flap is numerically investigated using computational fluid dynamics. A novel hybrid immersed boundary (IB) technique is applied...... to simulate the moving part of the trailing edge. Over the main fixed part of the airfoil the Navier-Stokes (NS) equations are solved using a standard body-fitted finite volume technique whereas the moving trailing edge flap is simulated with the immersed boundary method on a curvilinear mesh. The obtained...... results show that the hybrid approach is an efficient and accurate method for solving turbulent flows past airfoils with a trailing edge flap and flow control using trailing edge flap is an efficient way to regulate the aerodynamic loading on airfoils....

  3. Early Detection of Complete Vascular Occlusion in a Pedicle Flap Model Using Quantitation Spectral Imaging

    Science.gov (United States)

    Pharaon, Michael R.; Scholz, Thomas; Bogdanoff, Scott; Cuccia, David; Durkin, Anthony J.; Hoyt, David B.; Evans, Gregory R. D.

    2012-01-01

    Background Vascular occlusion after tissue transfer is a devastating complication that can lead to complete flap loss. Spatial frequency domain imaging is a new, noncontact, noninvasive, wide-field imaging technology capable of quantifying oxygenated and deoxygenated hemoglobin levels, total hemoglobin, and tissue saturation. Methods Pedicled fasciocutaneous flaps on Wistar rats (400 to 500 g) were created and underwent continuous imaging using spatial frequency domain imaging before and after selective vascular occlusion. Three flap groups (control, selective arterial occlusion, and selective venous occlusion) and a fourth group composed of native skin between the flaps were measured. Results There were no statistically significant differences between the control flap group and the experimental flap groups before selective vascular occlusion: oxyhemoglobin (p = 0.2017), deoxyhemoglobin (p = 0.3145), total hemoglobin (p = 0.2718), and tissue saturation,(p = 0.0777). In the selective arterial occlusion flap group, percentage change in total hemoglobin was statistically different from that of the control flap group (p = 0.0218). The remaining parameters were not statistically different from those of the control flap: percentage change in oxyhemoglobin (p = 0.0888), percentage change in deoxyhemoglobin (p = 0.5198), and percentage change in tissue saturation (p = 0.4220). The selective venous occlusion flap group demonstrated changes statistically different compared with the control flap group: percentage change in oxyhemoglobin (p = 0.0029) and deoxyhemoglobin, total hemoglobin, and tissue saturation (p oxyhemoglobin, deoxyhemoglobin, total hemoglobin, and tissue saturation. Results presented here indicate that this can be used to quantify and detect physiologic changes that occur after arterial and venous occlusion in a rodent tissue transfer flap model. This portable, noncontact, noninvasive device may have a high clinical applicability in monitoring postoperative

  4. Early detection of complete vascular occlusion in a pedicle flap model using quantitative [corrected] spectral imaging.

    Science.gov (United States)

    Pharaon, Michael R; Scholz, Thomas; Bogdanoff, Scott; Cuccia, David; Durkin, Anthony J; Hoyt, David B; Evans, Gregory R D

    2010-12-01

    Vascular occlusion after tissue transfer is a devastating complication that can lead to complete flap loss. Spatial frequency domain imaging is a new, noncontact, noninvasive, wide-field imaging technology capable of quantifying oxygenated and deoxygenated hemoglobin levels, total hemoglobin, and tissue saturation. Pedicled fasciocutaneous flaps on Wistar rats (400 to 500 g) were created and underwent continuous imaging using spatial frequency domain imaging before and after selective vascular occlusion. Three flap groups (control, selective arterial occlusion, and selective venous occlusion) and a fourth group composed of native skin between the flaps were measured. There were no statistically significant differences between the control flap group and the experimental flap groups before selective vascular occlusion: oxyhemoglobin (p=0.2017), deoxyhemoglobin (p=0.3145), total hemoglobin (p=0.2718), and tissue saturation, (p=0.0777). In the selective arterial occlusion flap group, percentage change in total hemoglobin was statistically different from that of the control flap group (p=0.0218). The remaining parameters were not statistically different from those of the control flap: percentage change in oxyhemoglobin (p=0.0888), percentage change in deoxyhemoglobin (p=0.5198), and percentage change in tissue saturation (p=0.4220). The selective venous occlusion flap group demonstrated changes statistically different compared with the control flap group: percentage change in oxyhemoglobin (p=0.0029) and deoxyhemoglobin, total hemoglobin, and tissue saturation (poxyhemoglobin, deoxyhemoglobin, total hemoglobin, and tissue saturation. Results presented here indicate that this can be used to quantify and detect physiologic changes that occur after arterial and venous occlusion in a rodent tissue transfer flap model. This portable, noncontact, noninvasive device may have a high clinical applicability in monitoring postoperative patients.

  5. Extended Active Disturbance Rejection Controller

    Science.gov (United States)

    Gao, Zhiqiang (Inventor); Tian, Gang (Inventor)

    2016-01-01

    Multiple designs, systems, methods and processes for controlling a system or plant using an extended active disturbance rejection control (ADRC) based controller are presented. The extended ADRC controller accepts sensor information from the plant. The sensor information is used in conjunction with an extended state observer in combination with a predictor that estimates and predicts the current state of the plant and a co-joined estimate of the system disturbances and system dynamics. The extended state observer estimates and predictions are used in conjunction with a control law that generates an input to the system based in part on the extended state observer estimates and predictions as well as a desired trajectory for the plant to follow.

  6. [Application of near infrared spectroscopy in monitoring blood oxygen saturation of fibula flaps].

    Science.gov (United States)

    Shan, Xiao-feng; Cai, Zhi-gang; Yu, Guang-yan; Li, Yue; Ding, Hai-shu

    2008-07-01

    To study the change of tissue oxygen index (TOI) by non-invasive near infrared spectroscopy (NIRS) and to investigate the blood flow variety of fibula flaps after operation. Thirty-six patients who accepted fibula flap reconstruction were chosen as subjects. Authors measured the TOI of the fibula flaps and the control side every four hours in the first twenty-four hours, and measured these positions with the intermittence of twelve hours from second to eighth day after operation. Thirty-five flaps were successful and one failed. The TOI of fibula flaps shortly after operation was significantly lower than that before the operation( P<0.05). In the successful cases the TOI of fibula flaps and the control sides was fluctuated from 50.0% to 72.0%. The TOI of fibula flaps was significantly lower than that of the control sides within 144 hours after operation(P<0.05). After 144 hours the TOI was equal to that of the control side. TOI of the failed case decreased dramatically. NIRS can reliably indicate the change of TOI in buried flaps and detect ischemia at the early stage. The TOI of the fibula flaps depress at the early stage and returns to normal at 144 hours after operation.

  7. [Clinical application of free perforator hypothenar flap for thumb pulp defect].

    Science.gov (United States)

    Xiao, Zhou; Yongjun, Rui; Mingyu, Xue; Yajun, Xu; Li, Qiang; Heping, Zheng

    2015-05-01

    To summarize the therapeutic effect of free perforator hypothenar flap for thumb pulp defect. From Jun. 2012 to Mar. 2013,8 cases with thumb pulp defect accompanied with exposure of phalanges ans tendons were treated by free ipsilateral perforator hypothenar flap. The flaps were 1.4 cm x 2.0 cm-1.8 cm x 2.2 cm in size. Ulnar finger artery in the flap was anastomosed with thumb artery. The accompanied veins and superficial veins were respectively anastomosed with thumb dorsal veins. Nerve branches in flaps were sutured with unilateral finger nerve to reconstruct flap feeling with 9-0 thread. Wounds in the hypothenar donor site were sutured directly. All the flaps survived completely with primary healing both in donor and recipient area. 8 cases (8 fingers) were followed up for 6-13 months (average 9 months). The flaps appearance, texture were good. The two-point discrimination distance on flap was 7-10 mm. The active and passive movement of thumb joints was normal. There was no complain about the feeling at the donor site. Linear scar was left on the donor site. Patients hand grip strength was not decreased. The free perforator hypothenar flap which has constant vascular anatomy is a new method for thumb soft tissue defect with less morbidity to donor site. The operative procedures are relatively simple.

  8. Spectral diffuse reflectance and autofluorescence imaging can perform early prediction of blood vessel occlusion in skin flaps.

    Science.gov (United States)

    Chen, Shuo; Zhu, Caigang; Hoe-Kong Chui, Christopher; Sheoran, Gyanendra; Tan, Bien-Keem; Liu, Quan

    2016-11-17

    Flap transfer has become a common technique in reconstructive surgery. However, a significant number of compromised skin flaps are not successfully salvaged because the current clinical method for flap assessment relies heavily on the clinician's experience. Vascular occlusion is the major reason for flap failure, thus the accurate and objective early prediction of blood vessel occlusion is vitally important. Our parallel point measurement study has demonstrated the great potential of joint diffuse reflectance and autofluorescence spectroscopy in the early detection and differentiation of venous and arterial occlusion in skin flaps. Unfortunately, the technique of point measurements is not suitable to examine a large skin flap when a high spatial resolution is required. In this study, we attempted to overcome this problem by performing spectral diffuse reflectance and autofluorescence imaging on a rat skin flap model. Both imaging data and reconstructed spectra were used to statistically differentiate control flaps, arterially occluded flaps and venously occluded flaps. Our preliminary results suggest that the technique of joint diffuse reflectance and autofluorescence spectroscopic imaging can achieve high classification accuracy thus could be used to detect and differentiate flaps with venous and arterial occlusion accurately at an early time point in a large skin flap. Typical reconstructed spectra of (a) diffuse reflectance and (b) autofluorescence after normalization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The use of active controls to augment rotor/fuselage stability

    Science.gov (United States)

    Straub, F. K.; Warmbrodt, W.

    1985-01-01

    The use of active blade pitch control to increase helicopter rotor/body damping is studied. Control is introduced through a conventional nonrotating swashplate. State variable feedback of rotor and body states is used. Feedback parameters include cyclic rotor flap and lead-lag states, and body pitch and roll rotations. The use of position, rate, and acceleration feedback is studied for the various state variables. In particular, the influence of the closed loop feedback gain and phase on system stability is investigated. For the rotor/body configuration analyzed, rotor cyclic inplane motion and body roll-rate and roll-acceleration feedback can considerably augment system damping levels and eliminate ground resonance instabilities. Scheduling of the feedback state, phase, and gain with rotor rotation speed can be used to maximize the damping augmentation. This increase in lead-lag damping can be accomplished without altering any of the system modal frequencies. Investigating various rotor design parameters (effective hinge offset, blade precone, blade flap stiffness) indicates that active control for augmenting rotor/body damping will be particularly powerful for hingeless and bearingless rotor hubs.

  10. Versatility of the thin groin flap.

    Science.gov (United States)

    Murakami, R; Fujii, T; Itoh, T; Tsutsui, K; Tanaka, K; Lio, Y; Yano, H

    1996-01-01

    The groin flap is one of the most usable flaps. It provides a large amount of skin coverage with an easily concealed donor site. However, when the flap is used to reconstruct areas of the neck, hand, or foot, a secondary procedure for defatting is usually necessary. Thinner flaps are thought to be more useful in these areas. We present an anatomical study of the thin groin flap, including its dissection and defatting, and 12 clinical cases using the thin groin flap for neck (n = 7), foot (n = 4), and scalp (n = 1) reconstruction. The largest successful flap measured 13 x 30 cm. Eight flaps survived completely, two had partial necrosis, and two had total necrosis. Complications were thought to be caused by dissection around the pedicle. Meticulous dissection and thinning are required to create the thin groin flap. Excellent aesthetic results requiring no secondary defatting procedures are possible with this new thin groin flap.

  11. Local and systemic coagulation marker response to musculocutaneous flap ischemia-reperfusion injury and remote ischemic conditioning: An experimental study in a porcine model.

    Science.gov (United States)

    Krag, Andreas Engel; Hvas, Christine Lodberg; Kiil, Birgitte Jul; Eschen, Gete Toft; Damsgaard, Tine Engberg; Hvas, Anne-Mette

    2018-01-08

    Remote ischemic conditioning (RIC) administered by non-lethal periods of extremity ischemia and reperfusion attenuates ischemia-reperfusion injury. We aimed to investigate the local and systemic coagulation marker response to flap ischemia-reperfusion injury, and the effects of RIC on coagulation markers following flap ischemia-reperfusion injury. A musculocutaneous latissimus dorsi flap was subjected to 4 h of ischemia followed by 7 h of reperfusion in 16 female Danish Landrace pigs (39 kg). Systemic venous blood samples were collected 1 h before flap reperfusion. Flap and systemic venous blood samples were collected at reperfusion and hourly during reperfusion. We measured thrombin generation, fibrinogen, von Willebrand factor, antithrombin, thrombin-antithrombin complex, activated partial thromboplastin time (aPTT), and prothrombin time (PT). RIC was performed 1 h before flap reperfusion in the intervention group by three 10-min periods of hind limb ischemia and reperfusion (n = 8). RIC was not performed in the control group (n = 8). Local and systemic coagulation marker changes were comparable following flap ischemia-reperfusion injury. Flap ischemia-reperfusion injury reduced thrombin generation lag time from 2.0 ± 0.3 to 1.6 ± 0.3 min (P < .001), time-to-peak thrombin from 3.5 ± 0.3 to 3.0 ± 0.5 min (P = .001), peak thrombin from 79.6 ± 8.1 to 74.5 ± 7.1 nM (P = .033), endogenous thrombin potential from 211 ± 24 to 197 ± 19 nM × min (P = .01), antithrombin from 0.91 ± 0.07 to 0.79 ± 0.06 103 IU/l (P = .002), and aPTT from 37 ± 21 to 21 ± 9 s (P = .017). RIC increased peak thrombin (P < .001), endogenous thrombin potential (P < .001), and aPTT (P = .019). The local coagulation marker response to musculocutaneous flap ischemia-reperfusion could be measured systemically by moderate hypercoagulation. RIC did not substantially influence

  12. Ethylene oxide sterilization of autologous bone flaps following decompressive craniectomy.

    Science.gov (United States)

    Missori, P; Polli, F M; Rastelli, E; Baiocchi, P; Artizzu, S; Rocchi, G; Salvati, M; Paolini, S; Delfini, R

    2003-10-01

    In patients undergoing decompressive craniectomy, the bone flap is temporarily preserved either in the subcutaneous tissue of the patient or frozen. However, there are some drawbacks related to these methods. In 16 patients in whom the bone flap was removed for decompressive craniectomy, the bone was firstly washed in hydrogen peroxide and then placed in hermetically-sealed bags and sterilized using ethylene oxide. The bone was repositioned after an average period of 4.3 months. One patient sustained an infection of the surgical wound which required permanent exclusion of the bone flap. In all the others, esthetic and functional results were good after an average follow-up of 20 months. Control CT-scan of the bone flap demonstrated preservation of its structural features with fusion of the bone margins and revitalization of the flap. On MRI a subdural space was again visible. Sterilization of the bone flap with ethylene oxide in patients undergoing decompressive craniectomy avoids some of the drawbacks related to the techniques currently used. The easiness, low cost, good aesthetic and functional results of this procedure make it a valid alternative to other techniques for preservation of autologous bone in decompressive craniectomies.

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

    Science.gov (United States)

    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.

  14. Novel Active Combustion Control Valve

    Science.gov (United States)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  15. Fractional active disturbance rejection control.

    Science.gov (United States)

    Li, Dazi; Ding, Pan; Gao, Zhiqiang

    2016-05-01

    A fractional active disturbance rejection control (FADRC) scheme is proposed to improve the performance of commensurate linear fractional order systems (FOS) and the robust analysis shows that the controller is also applicable to incommensurate linear FOS control. In FADRC, the traditional extended states observer (ESO) is generalized to a fractional order extended states observer (FESO) by using the fractional calculus, and the tracking differentiator plus nonlinear state error feedback are replaced by a fractional proportional-derivative controller. To simplify controller tuning, the linear bandwidth-parameterization method has been adopted. The impacts of the observer bandwidth ωo and controller bandwidth ωc on system performance are then analyzed. Finally, the FADRC stability and frequency-domain characteristics for linear single-input single-output FOS are analyzed. Simulation results by FADRC and ADRC on typical FOS are compared to demonstrate the superiority and effectiveness of the proposed scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  16. The Pedicled LICAP Flap Combined with a Free Abdominal Flap In Autologous Breast Reconstructions

    Directory of Open Access Journals (Sweden)

    Thomas Sjøberg, MD

    2018-01-01

    Conclusion:. In selected patients with insufficient abdominal flap tissue, a combination of a free abdominal flap and a pedicled LICAP flap is a valuable option to increase breast size and cosmetic outcome. Additional symmetrizing surgery might still be necessary.

  17. Dancing girl flap: a new flap suitable for web release.

    Science.gov (United States)

    Shinya, K

    1999-12-01

    To create a deep web, a flap must be designed to have a high elongation effect in one direction along the mid-lateral line of the finger and also to have a shortening effect in the other direction, crossing at a right angle to the mid-lateral line. The dancing girl flap is a modification of a four-flap Z-plasty with two additional Z-plasties. It has a high elongation effect in one direction (>550%) and a shortening effect in the other direction at a right angle (<33%), creating a deep, U-shaped surface. This new flap can be used to release severe scar contracture with a web, and is most suitable for incomplete syndactyly with webs as high as the proximal interphalangeal joint.

  18. Low-rise scar deep inferior epigastric artery perforator flap for breast reconstruction.

    Science.gov (United States)

    Akita, Shinsuke; Mitsukawa, Nobuyuki; Tokumoto, Hideki; Kuriyama, Motone; Kubota, Yoshitaka; Kira, Tomoe; Sasahara, Yoshitaro; Sakakibara, Masahiro; Nagashima, Takeshi; Satoh, Kaneshige

    2015-09-01

    To achieve an unnoticeable postoperative scar in patients with little abdominal skin laxity for breast reconstruction by deep inferior epigastric artery perforator (DIEP) flap, we devised a new design called the low-rise scar DIEP flap; the skin paddle of this flap is located lower with a smaller vertical width, and more adipose tissue is elevated to obtain enough volume. The purpose of this report is to evaluate the utility of the low-rise scar DIEP flap compared with that of the conventionally designed flap. Twelve patients who underwent low-rise scar DIEP flaps (study group) and 11 patients who underwent conventionally-designed DIEP flaps (control group) were included in the present study. The distance from the umbilicus to horizontal scar was divided by the patient's height. The length of the scar was divided by the abdominal circumference. These ratios were compared between groups. All flaps survived completely and no recipient site complication was observed, except for one case in the control group with small-range fat necrosis. No donor site complication was observed in either group. The distance ratio was significantly larger in study group (scar DIEP flap leaves a lower and shorter postoperative scar. © 2015 Wiley Periodicals, Inc.

  19. Micro-electro-mechanical flapping wing technology for micro air vehicles

    Science.gov (United States)

    Hall, Asha J.; Riddick, Jaret C.

    2012-04-01

    Army combat operations have placed a high premium on reconnaissance missions for Unmanned Aerial Vehicles (UAVs) and Micro Air Vehicles (MAVs) (less than 15 cm in dimension and less than 20 g in mass). One approach for accomplishing this mission is to develop a biologically inspired flapping wing insect that can maneuver into confined areas and possess hovering capabilities. Analysis of insect flight indicates that in addition to the bending excitation (flapping), simultaneous excitation of the twisting degree-of-freedom (pitching) is required to manipulate the control surface adequately. Traditionally, bimorph piezoelectric PZT (Pb(Zr0.55Ti0.45)O3) actuators have been used in many applications to excite the bending degree-of-freedom. In laminated or layered structures, bend-twist coupling is governed by the existence of at least one anisotropic layer not aligned with the primary plate axes. By adding a layer of off-axis PZT segments to a PZT bimorph actuator, thereby producing a layered structure to be referred to as a functionally- modified bimorph, bend-twist coupling may be introduced to the flexural response of the layered PZT. Furthermore, by selectively charging off-axis layers in specific combinations with the bimorph, the response of the functionally-modified bimorph may be tailored yielding a biaxial actuator to actively control the flapping wing response. The present study presents an experimental investigation of both traditional bimorph and functionally-modified PZT bimorph designs intended for active bend-twist actuation of cm-scale flapping wing devices.

  20. Aspects of the influence of an oscillating mini-flap upon the near wake of an airfoil NACA 4412

    Science.gov (United States)

    Delnero, J. S.; Marañón Di Leo, J.; Colman, J.; García Sainz, M.; Muñoz, F.; Hérouard, N.; Camocardi, M. E.

    2011-05-01

    A NACA 4412 airfoil was tested, in a boundary layer wind tunnel, with the aim to study the effect of a Gurney mini-flap, as an active and passive flow control device submitted to a turbulent flow field. The main objective was the experimental determination of flow pattern characteristics downstream the airfoil in the near wake. The untwisted wing model used for the experiments had 80cm wingspan and 50cm chord, with airfoil NACA 4412. The mini-flap was located on the lower surface at a distance, from the trailing edge, of 8%c (c airfoil chord). The Reynolds number, based upon the wing chord and the mean free stream velocity was 326,000 and 489,000. The turbulence intensity was 1.8%. The model was located into the wind tunnel between two panels, in order to assure a close approximation to two-dimensional flow over the model. As an active control device a rotating mini-flaps, geared by an electromechanical system (which rotate to a 30°) was constructed. The wake pattern and pressure values near the trailing edge were measured. The results obtained, for this mechanism, show us that the oscillating mini-flap change the wake flow pattern, alleviating the near wake turbulence and enhancing the vortex pair near the trailing edge at the mini-flap level and below that level, magnifying the effect described first by Liebeck [1]. That effect grows with the oscillating frequency. Additionally, the wake alleviation probably affects also the far wake. All of these facts suggest us to continue with the experiments, trying to measure the pressure distribution around the airfoil in all the cases, obtaining the lift and drag characteristics.

  1. The Technique and Benefits of Angiographic Embolization of Inferior Epigastric Arteries Prior to Pedicled TRAM Flap Breast Reconstruction: Results from a Single Center.

    Science.gov (United States)

    Sever, Alysse J; Patel, Chirag; Albeer, Yahya; Darian, Vigen B

    2017-12-01

    To report a single center's experience with selective arterial embolization of the deep inferior epigastric arteries (DIEA) prior to pedicled TRAM flap breast reconstruction including techniques and outcomes. Retrospective chart review was performed for 15 patients who underwent pedicled TRAM flap breast reconstruction after selective embolization of bilateral DIEA. Data were analyzed to display the spectrum of postoperative outcomes following the TRAM flap procedure status post-selective angiographic embolization of the bilateral DIEA to improve vascularity of the TRAM flaps by rendering the tissue partially ischemic to undergo neovascularization. We then compared our results to historical controls of those delayed by ligating the DIEA via traditional surgical means to see if the outcomes are similar. We also compared our results to historical non-delayed TRAM flap reconstruction. One patient had a small area of partial flap skin necrosis, and no patients had total flap loss. 13.3% of patients had clinically significant TRAM flap fat necrosis. Outcomes of TRAM flaps delayed by selective arterial embolization are comparable to historical controls of those delayed by traditional surgical means and better than non-delayed flaps. Angiographic delayed TRAM flap reconstruction procedure is a reasonable safe alternative to the surgical delayed TRAM flap reconstruction procedure with less morbidity and is better than non-delayed TRAM flap procedures.

  2. Shape and Structural Optimization of Flapping Wings

    Science.gov (United States)

    Stewart, Eric Colby

    This dissertation presents shape and structural optimization studies on flapping wings for micro air vehicles. The design space of the optimization includes the wing planform and the structural properties that are relevant to the wing model being analyzed. The planform design is parameterized using a novel technique called modified Zimmerman, which extends the concept of Zimmerman planforms to include four ellipses rather than two. Three wing types are considered: rigid, plate-like deformable, and membrane. The rigid wing requires no structural design variables. The structural design variables for the plate-like wing are the thickness distribution polynomial coefficients. The structural variables for the membrane wing control the in-plane distributed forces which modulate the structural deformation of the wing. The rigid wing optimization is performed using the modified Zimmerman method to describe the wing. A quasi-steady aerodynamics model is used to calculate the thrust and input power required during the flapping cycle. An assumed inflow model is derived based on lifting-line theory and is used to better approximate the effects of the induced drag on the wing. A multi-objective optimization approach is used since more than one aspect is considered in flapping wing design. The the epsilon-constraint approach is used to calculate the Pareto optimal solutions that maximize the cycle-average thrust while minimizing the peak input power and the wing mass. An aeroelastic model is derived to calculate the aerodynamic performance and the structural response of the deformable wings. A linearized unsteady vortex lattice method is tightly coupled to a linear finite element model. The model is cost effective and the steady-state solution is solved by inverting a matrix. The aeroelastic model is used to maximize the thrust produced over one flapping cycle while minimizing the input power.

  3. Active load control using microtabs

    Science.gov (United States)

    Yen, Dora Te-Lun

    2001-11-01

    Micro-electro-mechanical (MEM) translational tabs are introduced for enhancing and controlling the aerodynamic loading on lifting surfaces. These microtabs are mounted near the trailing edge of lifting surfaces, retract and extend approximately normal to the surface and have a maximum deployment height on the order of the boundary-layer thickness. Deployment of the device effectively modifies the camber distribution of the lifting surface and hence, the lift generated. The effect of the microtabs on lift is shown to be as powerful as conventional control surfaces with lift changes of 30%--50% in the linear range of the lift curve using a tab with a height of 1% of airfoil chord placed at 5% of chord upstream of the trailing edge on the lower surface. A multi-disciplinary approach incorporating aspects of experimental and computational aerodynamics, mechanical design and microfabrication techniques has been taken to develop and test a "proof of concept" model. Flow simulations, using a Reynolds-averaged Navier Stokes solver, have been conducted to optimize the size and placement of the devices based on trailing edge volume constraints. Numerical and experimental wind tunnel results are in good agreement, and both confirm that these micro-scale devices create macro-scale changes in aerodynamic loading. Application of this rather simple but innovative lift control system based on microfabrication techniques introduces a robust, dynamic control device and will allow for the miniaturization of conventional high lift and control systems. The result is a significant reduction in typical control system weight, complexity and cost. Also due to the minute size of these tabs, their activation and response times are much faster than that of conventional trailing edge devices. The "proof of concept" tab design, fabrication techniques, computational and experimental setup, and test results using a representative airfoil are presented in this research. (For more information, see

  4. Ornithopter Type Flapping Wings for Autonomous Micro Air Vehicles

    Directory of Open Access Journals (Sweden)

    Sutthiphong Srigrarom

    2015-05-01

    resonance phenomenon of a two-degree of freedom elastic system, that is, the wing is supported by the springs for flapping and feathering motions. Being oscillated close to the resonance frequency of the system, only by the torque in flapping motion, the amplitude gained is a few times higher than that of normal case. The first prototype was made from acrylic using a laser cutting machine. The wings were made up of carbon rods and kite material Ripstop. First test showed that the wings were too heavy for the mechanism to work. The third prototype was a smaller single gear crank design which was fabricated using a 3D printer. Initial test proved that the second prototype could withstand the high frequency flapping and near resonance amplitude as designed. With remote control, the third prototype was able to take off, climb, cruise and land in flapping mode successfully.

  5. Venous Complications in One Versus Two Vein Anastomoses in Head and Neck Free Flaps.

    Science.gov (United States)

    Khaja, Sobia F; Rubin, Nathan; Bayon, Rodrigo

    2017-10-01

    The purpose of this study was to compare rates of reexploration and flap failure in patients with 1- and 2-vein anastomoses in free flap reconstructions. Retrospective chart review of 300 patients undergoing free flap reconstruction to head and neck defects from 2010 to 2014. One venous anastomosis was performed in 229 patients, and 2 venous anastomoses were performed in 71 patients. The 1-vein group had significantly more reexplorations in the operating room (36/229, 15.7%) compared with the 2-vein group (4/71, 5.6%; P = .028), even when controlling for flap type ( P = .022). This finding remained true among radial forearm flaps (17/81, 21% vs 3/53, 5.7%; P = .024). The number of venous anastomoses was not significantly associated with flap failure, though patients with flap failure did have a significantly greater proportion of venous issues ( P < .001). Two-vein anastomoses do not appear to reduce rates of flap failure or postoperative venous thrombosis but are associated with a lower number of reexplorations in the operating room even after accounting for differences in flap types and surgeons.

  6. Smart helicopter rotors optimization and piezoelectric vibration control

    CERN Document Server

    Ganguli, Ranjan; Viswamurthy, Sathyamangalam Ramanarayanan

    2016-01-01

    Exploiting the properties of piezoelectric materials to minimize vibration in rotor-blade actuators, this book demonstrates the potential of smart helicopter rotors to achieve the smoothness of ride associated with jet-engined, fixed-wing aircraft. Vibration control is effected using the concepts of trailing-edge flaps and active-twist. The authors’ optimization-based approach shows the advantage of multiple trailing-edge flaps and algorithms for full-authority control of dual trailing-edge-flap actuators are presented. Hysteresis nonlinearity in piezoelectric stack actuators is highlighted and compensated by use of another algorithm. The idea of response surfaces provides for optimal placement of trailing-edge flaps. The concept of active twist involves the employment of piezoelectrically induced shear actuation in rotating beams. Shear is then demonstrated for a thin-walled aerofoil-section rotor blade under feedback-control vibration minimization. Active twist is shown to be significant in reducing vibra...

  7. Development and Investigation of a Flapping Rotor for Micro Air Vehicles

    Science.gov (United States)

    2007-01-01

    and transitioning to forward flight......................................... 9 Figure 9: Aerovironment “ Microbat ...depend on a forward airspeed to generate lift and utilize flapping to produce a forward thrust. The Aerovironment 10 Microbat , seen in Figure 9...is only one example of an MAV whose flapping motion is based upon avian flight [12]. The wings of the Microbat do not actively change shape

  8. The protective efficacy and safety of bandage contact lenses in children aged 5 to 11 after frontalis muscle flap suspension for congenital blepharoptosis: A single-center randomized controlled trial.

    Science.gov (United States)

    Chen, Lin; Pi, Lianhong; Ke, Ning; Chen, Xinke; Liu, Qing

    2017-09-01

    Postoperative complications, lagophthalmos and exposure keratopathy sometimes occur after surgery for congenital blepharoptosis. Bandage contact lenses (BCL) can help prevent some ocular surface disorders. The study aims to evaluate the efficacy and safety of BCL for protection of the ocular surface in children aged 5 to 11 years after frontalis muscle flap suspension for congenital blepharoptosis. We conducted a prospective randomized clinical study of 30 eyes of 30 patients with congenital blepharoptosis consecutively enrolled at the Ophthalmology Ward of the Children's Hospital of Chongqing Medical University, China from September 1, 2016, to February 30, 2017. After frontalis muscle flap suspension surgery, patients were randomly assigned to undergo BCL application (BCL group, 15 eyes) or no BCL application (control group, 15 eyes). All patients were treated with bramycin 0.3% and polyvinyl alcohol drops after surgery. The primary outcomes were dry eye assessed by tear film break time (TFBUT), fluoresce in corneal staining (FCS) on slit-lamp on days 1, 3, and 15 postoperatively, and lower tear meniscus height (LTMH) on optical coherence tomography on days 1 and 15 postoperatively. Secondary outcomes were pairwise correlation of TFBUT, FCS and LTMH. In the BCL group, abnormal TFBUT and FCS were only found in 2 patients (13.33%) on postoperative day 15. In the control group, the incidence of dry eye assessed by TFBUT was 67.00% (10/15 eyes) on day 1, 73.33% (11/15 eyes) on day 3, and 53.33% (8/15 eyes) on day 15 (P < .001). LTMH were significantly higher in the BCL group than the control group postoperatively (P < .001). Significant positive correlations were found between LTMH and TFBUT pre-operation and on days 1 and 15 post-operation. For LTMH and FCSS (R = -0.815, P < .001), and TFBUT and FCS (R = -0.837, P < .001), the Pearson coefficient was negative on postoperative day 1, but not correlated on day 15. Silicone hydrogel BCL were

  9. Remote ischemic perconditioning attenuates acute inflammation of experimental musculocutaneous flaps following ischemia-reperfusion injury.

    Science.gov (United States)

    Krag, Andreas E; Eschen, Gete T; Damsgaard, Tine E; Svaerdborg, Mille; Steiniche, Torben; Kiil, Birgitte J

    2017-02-01

    In free flap reconstruction and replantation surgery, prolonged ischemia time may lead to flap or replantation failure. The aim of the study was to investigate the effects of hypothermic flap ischemia or remote ischemic perconditioning (RIPER) during normothermic ischemia on acute inflammation of musculocutaneous flaps subjected to ischemia-reperfusion injury. In 24 pigs, a musculocutaneous latissimus dorsi flap was dissected and subjected to 4 hours of arterial ischemia and 7 hours of reperfusion. The animals were allocated into two experimental groups: hypothermic flap ischemia at 4°C (n = 8) or normothermic flap ischemia with RIPER (n = 8), and one control group with normothermic flap ischemia (n = 8). The hypothermic ischemic flaps were cooled in a basin with fresh water and ice. RIPER was initiated 1 hour before reperfusion, by inducing three 10 min cycles of hind limb ischemia with a tourniquet, each separated by 10 min of reperfusion. Acute inflammation was described by inflammatory cytokine secretion (IL-1β, IL-6, IL-10, IL-12p40, and TNF-α) from the flap during reperfusion, and by quantitative determination of macrophages in flap biopsies of dermis, subcutaneous tissue, and skeletal muscle following reperfusion. No significant differences were found between normothermic and hypothermic flap ischemia in inflammatory cytokine secretion. However, the IL-6 secretion was significantly reduced in the RIPER group compared with the control group at 5 hours of reperfusion (P = 0.036), and in the RIPER group compared with the hypothermic ischemia group at 3 (P = 0 0.0063), 5 (P = 0.0026), and 7 hours of reperfusion (P = 0.028). The IL-12p40 secretion was significantly reduced in the RIPER group compared with the control group (P = 0.0054) as well as the hypothermic ischemia group (P = 0.028) at 5 hours of reperfusion. No significant difference was found among groups in macrophage infiltration. RIPER reduced IL-6 and IL-12p40 secretion

  10. Development of smart blade technology - trailing edge flaps

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge

    2014-01-01

    With blade lengths presently up to 80+ m there is a need for a supplement to the standard pitch system for control of power and loads. Distributed load control along the blade span with trailing edge flaps is a promising concept where numerical simulations have shown considerable load alleviation...

  11. Gracilis Flap Reconstruction of the Perineum: An Outcomes Analysis.

    Science.gov (United States)

    Singh, Mansher; Kinsley, Sarah; Huang, Anne; Ricci, Joseph A; Clancy, Thomas E; Irani, Jennifer; Goldberg, Joel; Breen, Elizabeth; Bleday, Ronald; Talbot, Simon G

    2016-10-01

    Immediate reconstruction of perineal defects secondary to abdominoperineal resection (APR) or pelvic exenteration with pedicled flaps decreases postoperative wound complications when compared with direct closure in high-risk patients. Although some authors have been proponents of abdominal-based flaps, here we evaluate the role for thigh-based flaps founded on acceptable outcomes and low morbidity. Consecutive patients referred to a single surgeon between January 2012 and August 2015 who underwent perineal reconstruction with a pedicled gracilis flap were identified. Patients were evaluated for routine preoperative variables and outcomes data were analyzed, including time to healing and abdominal and perineal complications. Forty patients were included in the study, with a mean follow-up period of 2 years. There were no 30-day mortalities and 37 patients (92.5%) were alive at the last follow-up. Five patients (12.5%) experienced donor site complications and 16 patients (40%) had recipient site complications, including hematoma, seroma, or dehiscence. Minor complications were seen in 10 (25%) patients, and 7 (17.5%) patients had major complications. Obesity (odds ratio = 7.5; p = 0.01) and active smoking status (odds ratio = 9.3; p = 0.01) were significantly associated with minor complications, and a history of neoadjuvant chemoradiation (odds ratio = 21.4; p = 0.04) was a significant risk factor for any complication. The overall complication rate with this technique is comparable with the more commonly used vertical rectus abdominis myocutaneous flap, but the potential for, and severity of, donor site complications is reduced with this technique. As such, gracilis flaps can be considered an acceptable alternative to abdominal flaps for selected perineal wounds. Copyright © 2016 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  12. The "Tokyo" consensus on propeller flaps.

    Science.gov (United States)

    Pignatti, Marco; Ogawa, Rei; Hallock, Geoffrey G; Mateev, Musa; Georgescu, Alexandru V; Balakrishnan, Govindasamy; Ono, Shimpei; Cubison, Tania C S; D'Arpa, Salvatore; Koshima, Isao; Hyakusoku, Hikko

    2011-02-01

    Over the past few years, the use of propeller flaps, which base their blood supply on subcutaneous tissue or isolated perforators, has become increasingly popular. Because no consensus has yet been reached on terminology and nomenclature of the propeller flap, different and confusing uses of the term can be found in the literature. In this article, the authors report the consensus on the definition and classification of propeller flaps reached by the authors that gathered at the First Tokyo Meeting on Perforator and Propeller Flaps in June of 2009. Some peculiar aspects of the surgical technique are discussed. A propeller flap can be defined as an "island flap that reaches the recipient site through an axial rotation." The classification is based on the nourishing pedicle (subcutaneous pedicled propeller flap, perforator pedicled propeller flap, supercharged propeller flap), the degrees of skin island rotation (90 to 180 degrees) and, when possible, the artery of origin of the perforator. The propeller flap is a useful reconstructive tool that can achieve good cosmetic and functional results. A flap should be called a propeller flap only if it fulfils the definition above. The type of nourishing pedicle, the source vessel (when known), and the degree of skin island rotation should be specified for each flap.

  13. Combined posterior flap and anterior suspended flap dacryocystorhinostomy: A modification of external dacryocystorhinostomy

    Directory of Open Access Journals (Sweden)

    Amarendra Deka

    2010-01-01

    Conclusion : We believe that combined posterior flap and anterior suspended flap DCR technique is simple to perform and has the advantage of both double flap DCR and anterior suspension of anterior flaps. The results of the study showed the efficacy of this simple modification.

  14. 14 CFR 23.701 - Flap interconnection.

    Science.gov (United States)

    2010-01-01

    ... Systems § 23.701 Flap interconnection. (a) The main wing flaps and related movable surfaces as a system... on one side of the plane of symmetry inoperative and the remaining engines at takeoff power. For...

  15. [Anterolateral thigh perforator flaps for facial reconstruction after tumour surgery].

    Science.gov (United States)

    Gaggl, Alexander; Bürger, Heinz; Lesnik, Gerald; Müller, Ernst; Chiari, Friedrich

    2006-09-01

    Individual flap design and minor donor site morbidity are main criteria in the treatment of facial defects after tumour surgery. Microvascular perforator flaps seem to follow these criteria well. In the following study our experiences with microvascular anterolateral thigh perforator flaps (ALTPF) in reconstruction of the face following ablative tumour surgery are described and discussed in comparison to the present literature. In 19 patients with squamous cell carcinomas of the floor of the mouth (8), the cheek (6) or the mandible (5) of stadium T3 or T4 ablative tumour surgery followed by reconstruction was performed. For covering the soft tissue defects 19 ALTPF were used. In the five patients with carcinomas of the mandible a microvascular iliac crest transplant was combined with the anterolateral thigh perforator flap for complete chin reconstruction. In one patient an intraoperative dissection of the perforator vessels happened. In all other patients surgery and postoperative period was free of complications. Five patients had minor second surgery for aesthetic of functional reasons. At the end there were good aesthetic and functional results in every patient. The anterolateral thigh perforator flap is of great advantage in reconstruction of the face after tumour surgery. Individual designing, central and save perfusion, easy to be controlled, and a low incidence of donor site morbidity are their main advantages.

  16. Flapping and flexible wings for biological and micro air vehicles

    Science.gov (United States)

    Shyy, Wei; Berg, Mats; Ljungqvist, Daniel

    1999-07-01

    Micro air vehicles (MAVs) with wing spans of 15 cm or less, and flight speed of 30-60 kph are of interest for military and civilian applications. There are two prominent features of MAV flight: (i) low Reynolds number (10 4-10 5), resulting in unfavorable aerodynamic conditions to support controlled flight, and (ii) small physical dimensions, resulting in certain favorable scaling characteristics including structural strength, reduced stall speed, and low inertia. Based on observations of biological flight vehicles, it appears that wing motion and flexible airfoils are two key attributes for flight at low Reynolds number. The small size of MAVs corresponds in nature to small birds, which do not glide like large birds, but instead flap with considerable change of wing shape during a single flapping cycle. With flapping and flexible wings, birds overcome the deteriorating aerodynamic performance under steady flow conditions by employing unsteady mechanisms. In this article, we review both biological and aeronautical literatures to present salient features relevant to MAVs. We first summarize scaling laws of biological and micro air vehicles involving wing span, wing loading, vehicle mass, cruising speed, flapping frequency, and power. Next we discuss kinematics of flapping wings and aerodynamic models for analyzing lift, drag and power. Then we present issues related to low Reynolds number flows and airfoil shape selection. Recent work on flexible structures capable of adjusting the airfoil shape in response to freestream variations is also discussed.

  17. Reconstruction of fingertip defects with digital artery perforator flap.

    Science.gov (United States)

    Özcanlı, Haluk; Bektaş, Gamze; Cavit, Ali; Duymaz, Ahmet; Coşkunfırat, O Koray

    2015-01-01

    The aim of this study was to present our findings for the use of the digital artery perforator (DAP) flap in the covering of digital pulp defects. The study included 15 patients who underwent reconstruction of the fingertip using a DAP flap between July 2007 and February 2012. The blood supply of the perforator island flap was based on the distal and either radial or ulnar sides of the digit. Donor sites were closed using skin grafting in all cases. Static two-point discrimination (s2PD) and Semmes-Weinstein monofilament (SWM) testing was performed at the final follow-up to determine extension loss and sensorial improvement. Mean follow-up was 22 (range: 7 to 62) months. Flaps size was between 2 x 1 cm and 2.5 x 1.5 cm. Temporary venous congestion was observed in 12 of the 15 patients and was without complication. All patients returned to their normal daily activities and work within an average of 39 (range: 30 to 45) days. Mean two-point discrimination was 5.3 mm and SWM test results were between 3.61 and 4.56 at the final follow-up. The DAP flap appears to be a reliable procedure with several advantages as a single-stage operating procedure, easy to harvest, good sensory recovery and preservation of digital arteries.

  18. Wind-Tunnel Investigation of Control-Surface Characteristics. 4 - A Medium Aerodynamic Balance of Various Nose Shapes Used with a 30-Percent-Chord Flap on an NACA 0009 Airfoil

    Science.gov (United States)

    1941-09-01

    rid.4(d).) . > ,.. . .. . .. .. . . . ‘ . . . Hinge ~omeri~s of the” E’lap The effect of the presence of a gap, gap size, and flap-nose shape on the...balance effectiveness with the largest gap for all angles of attack investigated. Nor the f,laps with the 0..35cf overhang, however, the effect of the presence of gap

  19. Vascularized Fibula Flaps for Mandibular Reconstruction: An ...

    African Journals Online (AJOL)

    For decades, osseous vascularised flaps have been used for reconstruction of the mandible with the vascularised fibula flap (VFF) remaining the commonly used osseous free flap, reasons ranging from its adequate bone and pedicle length to its receptive dental implant placement quality. This report considers a modest use ...

  20. New model of flap-gliding flight.

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Active Load Control Using a Non-traditional MEMs Approach

    Science.gov (United States)

    Yen Nakafuji, Dora; van Dam, Cornelis

    2001-11-01

    An active load control concept using micro-electro-mechanical (MEM) translational tabs has been undergoing testing and development at the University of California at Davis. The concept utilizes microfabricated sliding components to retract and extend small tabs located near the trailing edge of a lifting surface. The tab assembly, referred to as a microtab, extends approximately normal to the surface and has a maximum deployment height on the order of the boundary-layer thickness. Deployment of these retractable devices on either the suction or pressure side of a lifting surface effectively modifies the camber distribution and changes the lift and moments generated. On the pressure side, the effect of the microtabs on lift is shown to be as powerful as conventional flap-like control surfaces resulting in positive DCl changes of 30conventional control surfaces which typically occupy 20of the lifting surface, these large-scale load changes are achieved using microtabs with heights of 1located 5suction side, these microtabs work by decreasing the lift resulting in negative DCl changes in the linear range of the lift curve. Numerical and experimental wind tunnel results are in good agreement, and both confirm that these micro-scale devices are capable of generating macro-scale changes in the aerodynamic loading. Application of this rather simple but innovative load control system based on microfabrication techniques will allow for miniaturization of conventional systems. With further development and integration with an activation and feedback network, these microtabs may result in significant reductions in typical control system weight, complexity and cost. Due to their minute size, the activation and response times are expected to be much faster than that of conventional trailing edge devices. Using a multi-disciplinary approach incorporating aspects of experimental and computational aerodynamics, mechanical design and microfabrication, the potentials of this concept

  2. Global-local optimization of flapping kinematics in hovering flight

    KAUST Repository

    Ghommem, Mehdi

    2013-06-01

    The kinematics of a hovering wing are optimized by combining the 2-d unsteady vortex lattice method with a hybrid of global and local optimization algorithms. The objective is to minimize the required aerodynamic power under a lift constraint. The hybrid optimization is used to efficiently navigate the complex design space due to wing-wake interference present in hovering aerodynamics. The flapping wing is chosen so that its chord length and flapping frequency match the morphological and flight properties of two insects with different masses. The results suggest that imposing a delay between the different oscillatory motions defining the flapping kinematics, and controlling the way through which the wing rotates at the end of each half stroke can improve aerodynamic power under a lift constraint. Furthermore, our optimization analysis identified optimal kinematics that agree fairly well with observed insect kinematics, as well as previously published numerical results.

  3. Aerodynamic characteristics of the ventilated design for flapping wing micro air vehicle.

    Science.gov (United States)

    Zhang, G Q; Yu, S C M

    2014-01-01

    Inspired by superior flight performance of natural flight masters like birds and insects and based on the ventilating flaps that can be opened and closed by the changing air pressure around the wing, a new flapping wing type has been proposed. It is known that the net lift force generated by a solid wing in a flapping cycle is nearly zero. However, for the case of the ventilated wing, results for the net lift force are positive which is due to the effect created by the "ventilation" in reducing negative lift force during the upstroke. The presence of moving flaps can serve as the variable in which, through careful control of the areas, a correlation with the decrease in negative lift can be generated. The corresponding aerodynamic characteristics have been investigated numerically by using different flapping frequencies and forward flight speeds.

  4. Corneal hysteresis, resistance factor, topography, and pachymetry after corneal lamellar flap.

    Science.gov (United States)

    Gatinel, Damien; Chaabouni, Slim; Adam, Pierre-Alexandre; Munck, Jacques; Puech, Michel; Hoang-Xuan, Thanh

    2007-01-01

    To measure prospectively the early changes in corneal hysteresis, topography, and pachymetry after the creation of a stromal flap cut without laser photoablation. A 37-year-old man was referred for a bioptic procedure to correct for compound myopic astigmatism in the left eye. A 159-microm-thick 8x8.5-mm superior hinged flap was created with a mechanical microkeratome in the left cornea. Changes in the corneal hysteresis, corneal resistance factor, Goldmann correlated intraocular pressure (lOP), corneal compensated IOP, anterior and posterior topography, and optical and ultrasound pachymetry were monitored prospectively before and at 1 hour, 1 day, 5 days, and 25 days after flap creation. The right eye served as a control. In the left eye, corneal hysteresis and corneal resistance factor decreased immediately after the flap cut and remained lower than preoperatively at 1 hour, 1 day, 5 days, and 25 days. Corneal compensated IOP varied significantly less than Goldmann correlated IOP in both eyes. Central flattening of the horizontal meridians was observed on the difference topography maps. The values of the left eye posterior best fit sphere increased after the flap cut. Increased central corneal thickness occurred immediately after the flap cut and decreased over time without returning to its preoperative value. The creation of a stromal flap can modify the biomechanical properties of the cornea, including a reduction in corneal hysteresis. The topographic changes were consistent with previously reported cases of flap cut in normal corneas.

  5. Microbial contamination assessment of cryostored autogenous cranial bone flaps: should bone biopsies or swabs be performed?

    Science.gov (United States)

    Bhaskar, Ivan P; Inglis, Timothy J J; Bowman, Jacintha; Lee, Gabriel Y F

    2013-02-01

    Autogenous cranioplasty infection requiring bone flap removal is under-recognised as a major complication causing significant morbidity. Microbial contamination of stored bone flaps may be a significant contributing factor. Current infection control practices and storage procedures vary. It is not known whether 'superficial' swabs or bone cultures provide a more accurate assessment. Twenty-five skull flaps that were cryo-stored for more than 6 months were studied. Two swab samples (superficial and deep) and a bone biopsy sample were taken from each skull flap sample and cultured. Half blood agar and half chocolate agar plates were inoculated with the swabs for anaerobic and aerobic cultures respectively. The bone biopsy samples were cultured in brain-heart broth and subcultured similar to the swabs for 5 days. Incidence of microbial contamination was 20 % in the bone flaps studied. One swab culture and five bone biopsy cultures were positive for bacterial growth, all of which contained Propionibacterium acnes (p = 0.014). Positive cultures were from bone flaps stored less than 18 months, whereas no growth was obtained from bone flaps that were stored longer (p = 0.014). Bone biopsy culture is a more sensitive technique of assessing microbial contamination of cryo-stored autogenous bone flaps than swab cultures. The clinical implications of in vitro demonstration of microbial contamination require further study.

  6. Determination of trim curves for a flapping-wing MAV

    NARCIS (Netherlands)

    Armanini, S.F.; Verboom, J.L.; De Croon, G.C.H.E.; De Visser, C.C.

    2014-01-01

    This paper presents the results of a series of flight tests conducted in order to assess the steady-state flight characteristics and basic control behaviour of the DelFly, a flapping-wing micro aerial vehicle (FWMAV). Flights were conducted in an indoor motion tracking facility and included

  7. Etanercept protects myocutaneous flaps from ischaemia reperfusion injury: An experimental study in a rat tram flap model.

    Science.gov (United States)

    Ersoy, Burak; Çevik, Özge; Çilingir, Özlem Tuğçe

    2016-08-01

    Background Being an inevitable component of free tissue transfer, ischemia-reperfusion injury tends to contribute to flap failure. TNF-α is an important proinflammatory cytokine and a prominent mediator of the ischemia-reperfusion injury. Etanercept, a soluble TNF-α binding protein, has shown anti-inflammatory and anti-apoptotic effects in animal models of renal and myocardial ischemia-reperfusion injury. We have designed an experimental study to investigate the effect of etanercept on myocutaneous ischemia-reperfusion injury on transverse rectus abdominis myocutaneous flap model in rats. Methods Twenty-four male Sprague-Dawley rats were divided into 3 groups: In group 1 (sham), the TRAM flap was raised and sutured back without further intervention. In group 2 (control), the flap was raised and the ischemia-reperfusion protocol was followed. In group 3, etanercept (10 mg/kg, i.v.) was administered 10 minutes before reperfusion. At the end of the reperfusion period, biochemical and histolopathological evaluations were performed on serum and tissue samples. Results In the etanercept group the IMA and 8-OHdG levels (p = 0.005 and p = 0.004, respectively) were found significantly lower, and the GSH and SOD levels (p = 0.01 and p etanercept group compared to the control group. Conclusion The results of our experimental study indicate that etanercept offers protection against ischemia-reperfusion injury in skeletal muscle tissue, enhancing the TRAM flap viability. The ability of etanercept to induce ischemic tolerance suggests that it may be applicable in free-flap surgery.

  8. System noise assessment of an aircraft with coanda flaps

    NARCIS (Netherlands)

    Blinstrub, J.; Heinze, W; Bertsch, E.L.; Simons, D.G.; Snellen, M.

    2016-01-01

    An innovative aircraft design of the Collaborative Research Centre (SFB) 880 features a new active high-lift system. This high-lift system is comprised of a droop-nose leading edge device and a Coanda flap as the trailing edge device. It offers very high lift coefficients and thus the ability to

  9. Flapping rates of migrating and foraging Turkey Vultures Cathartes ...

    African Journals Online (AJOL)

    Local and migrating populations of Turkey Vultures Cathartes aura co-exist in Costa Rica in autumn and spring (Stiles & Skutch 1989). We studied the flapping rates of individuals from these two populations to compare flight modes and the amount of energy invested in active flight. Migrants tended to fly higher in more ...

  10. Platelet-rich plasma reduces skin flap inflammatory cells infiltration and improves survival rates through induction of angiogenesis: An experiment in rabbits.

    Science.gov (United States)

    Wang, Biao; Geng, Qiuhua; Hu, Junling; Shao, Jianchuan; Ruan, Jing; Zheng, Jiansheng

    2016-08-01

    This study was conducted to evaluate the effects of platelet-rich plasma (PRP) on flap survival in an experimental rabbit model. Symmetrical rectangular dorsal cutaneous flaps (8 × 2 cm) were elevated in 15 rabbits. The rabbits were randomly divided into a 3-day group (n = 5), a 7-day group (n = 5), and a 14-day group (n = 5). Either side of the dorsum was selected for injection of PRP into the flap basal surface, while the other side received an equal volume of saline as a control. The flaps were immediately sutured back, after which the flap survival was measured and histology specimens were collected at 3, 7, and 14 days. Platelet-rich plasma significantly improved flap survival rates of the PRP side flaps relative to the control in the 3-day (74.4% ± 4.7% vs 65.8% ± 6.8%; p platelet-rich plasma side flap vs the blank control side flap. Platelet-rich plasma (PRP) promotes the survival of random rabbit flaps and, therefore, represents a promising treatment to prevent skin flap necrosis in reconstructive and plastic surgery.

  11. Sternocleidomastoid Muscle Flap after Parotidectomy

    Directory of Open Access Journals (Sweden)

    Nofal, Ahmad Abdel-Fattah

    2015-04-01

    Full Text Available 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.

  12. The inner arm fasciocutaneous flap.

    Science.gov (United States)

    Budo, J; Finucan, T; Clarke, J

    1984-04-01

    A fasciocutaneous flap raised on the inner surface of the upper arm has been used to release 16 burn scar contractures of the anterior axillary fold. It is a relatively quick and simple procedure that adequately corrects the contracture and does not have to followed by prolonged splinting.

  13. Control system design of active seat suspensions

    Science.gov (United States)

    Maciejewski, I.

    2012-03-01

    This paper presents an approach to the control system design of seat suspension systems for the active vibration attenuation. The paper presents the studies of the active vibration control strategy based on the reverse dynamics of force actuator and the primary controller. The multi-criteria optimization procedure is utilized in order to calculate the primary controller settings which subsequently define the vibro-isolation characteristics of active suspensions. As an example of the proposed control system design, the seat with a pneumatic suspension is investigated and its vibro-isolation properties are shaped by an appropriate selection of the controller settings.

  14. Smart rotor modeling aero-servo-elastic modeling of a smart rotor with adaptive trailing edge flaps

    CERN Document Server

    Bergami, Leonardo

    2014-01-01

    A smart rotor is a wind turbine rotor that, through a combination of sensors, control units and actuators actively reduces the variation of the aerodynamic loads it has to withstand. Smart rotors feature?promising load alleviation potential and might provide the technological breakthrough required by the next generation of large wind turbine rotors.The book presents the aero-servo-elastic model of a smart rotor with Adaptive Trailing Edge Flaps for active load alleviation and provides an insight on the rotor aerodynamic, structural and control modeling. A novel model for the unsteady aerodynam

  15. Effect of natural hirudin on random pattern skin flap survival in a porcine model.

    Science.gov (United States)

    Zhao, H; Shi, Q; Sun, Z Y; Yin, G Q; Yang, H L

    2012-01-01

    The effect of local administration of hirudin on random pattern skin flap survival was investigated in a porcine model. Three random pattern skin flaps (4 × 14 cm) were created on each flank of five Chinese minipigs. The experimental group (10 flaps) received 20 antithrombin units of hirudin, injected subdermally into the distal half immediately after surgery and on days 1 and 2; a control group (10 flaps) was injected with saline and a sham group (10 flaps) was not injected. All flaps were followed for 10 days postoperatively. Macroscopically, the congested/necrotic length in the experimental group was significantly decreased compared with the other two groups by day 3. Histopathological evaluation revealed venous congestion and inflammation in the control and sham groups from day 1, but minimal changes in the experimental group. By day 10, the mean ± SD surviving area was significantly greater in the experimental group (67.6 ± 2.1%) than in the control (45.2 ± 1.4%) or sham (48.3 ± 1.1%) groups. Local administration of hirudin can significantly increase the surviving area in overdimensioned random pattern skin flaps, in a porcine model.

  16. Vibration reduction in helicopter rotors using an active control surface located on the blade

    Science.gov (United States)

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

    1992-01-01

    A feasibility study of vibration reduction in a four-bladed helicopter rotor using individual blade control (IBC), which is implemented by an individually controlled aerodynamic surface located on each blade, is presented. For this exploratory study, a simple offset-hinged spring restrained model of the blade is used with fully coupled flap-lag-torsional dynamics for each blade. Deterministic controllers based on local and global system models are implemented to reduce 4/rev hub loads using both an actively controlled aerodynamic surface on each blade as well as conventional IBC, where the complete blade undergoes cyclic pitch change. The effectiveness of the two approaches for simultaneous reduction of the 4/rev hub shears and hub moments is compared. Conventional IBC requires considerably more power to achieve approximately the same level of vibration reduction as that obtained by implementing IBC using an active control surface located on the outboard segment of the blade. The effect of blade torsional flexibility on the vibration reduction effectiveness of the actively controlled surface was also considered and it was found that this parameter has a very substantial influence.

  17. Cooperative Control Method of Active and Semiactive Control: New Framework for Vibration Control

    OpenAIRE

    Kazuhiko Hiramoto

    2014-01-01

    A new control design framework for vibration control, the cooperative control of active and semiactive control, is proposed in the paper. In the cooperative control, a structural system having both of an actuator and a semiactive control device, for example, MR damper and so forth, is defined as the control object. In the proposed control approach, the higher control performance is aimed by the cooperative control between the active control with the actuator and the semiactive control with th...

  18. Developing Internal Controls through Activities

    Science.gov (United States)

    Barnes, F. Herbert

    2009-01-01

    Life events can include the Tuesday afternoon cooking class with the group worker or the Saturday afternoon football game, but in the sense that Fritz Redl thought of them, these activities are only threads in a fabric of living that includes all the elements of daily life: playing, working, school-based learning, learning through activities,…

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

    Energy Technology Data Exchange (ETDEWEB)

    Baytinger, V. F., E-mail: baitinger@mail.tomsknet.ru; Kurochkina, O. S., E-mail: kurochkinaos@yandex.ru; Selianinov, K. V.; Baytinger, A. V. [Research Institute of Microsurgery, Tomsk (Russian Federation); Dzyuman, A. N. [Siberian State Medical University, Tomsk (Russian Federation)

    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.

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

    Science.gov (United States)

    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.

  1. A split mouth randomized controlled study to evaluate the adjunctive effect of platelet-rich fibrin to coronally advanced flap in Miller's class-I and II recession defects

    Science.gov (United States)

    Padma, Rajan; Shilpa, Ande; Kumar, Pavaluri Aravind; Nagasri, Meganderao; Kumar, Chetan; Sreedhar, Annaji

    2013-01-01

    Background: There are various techniques developed to treat the exposed roots, a recent innovation in dentistry is the use of second generation platelet concentrate which is an autologous platelet-rich fibrin gel (PRF) with growth factors and cicatricial properties for root coverage procedures. Therefore, the present research was undertaken to study the additional benefits of PRF when used along with coronally advanced flap (CAF). Materials and Methods: Total of 15 systemically healthy subjects presenting bilateral isolated Miller's class I and II recession were enrolled into the study. Each patient was randomly treated with a combination of CAF along with a platelet-rich fibrin (PRF) membrane on the test site and CAF alone on the control site. Recession depth, clinical attachment level (CAL), and width of keratinized gingiva (WKG) were compared with baseline at 1, 3, and 6 months between test and control sites. Results: Mean percentage root coverage in the test group after 1, 3, and 6 months was 34.58, 70.73, and 100, respectively. Differences between the control and test groups were statistically significant. This study also showed a statistically significant increase in WKG in the test group (2.94 ± 0.77 at baseline to 5.38 ± 1.67 at 6 months). Conclusion: CAF is a predictable treatment for isolated Miller's class I and II recession defects. The addition of PRF membrane with CAF provides superior root coverage with additional benefits of gain in CAL and WKG at 6 months postoperatively. PMID:24174758

  2. Vibration control of active structures an introduction

    CERN Document Server

    Preumont, Andre

    2002-01-01

    This text is an introduction to the dynamics of active structures and to the feedback control of lightly damped flexible structures. The emphasis is placed on basic issues and simple control strategies that work.

  3. Natural Hirudin Increases Rat Flap Viability by Anti-Inflammation via PARs/p38/NF-κB Pathway

    Directory of Open Access Journals (Sweden)

    Liu Peng

    2015-01-01

    Full Text Available The present study aimed to evaluate the effect of natural hirudin on rat random skin flap viability and to determine the mechanism. Forty-eight rats were randomly divided into 2 groups. After the dorsal skin flap operation (3 cm × 10 cm in size, subcutaneous injections of 6 ATU hirudin were administered to group H (n=24 every 12 h, while group C (n=24 received an equal volume of 0.9% normal saline. Six rats from each group were euthanized 1, 2, 4, and 7 days after the operation. A full skin sample was collected from these rats to measure the p38-mitogen-activated protein kinase (p38-MAPK, phospho-p38- (Pp38- MAPK, nuclear factor-κB (NF-κB p65, phosphor-NF-κB (pNF-κB p65, tumour necrosis factor- (TNF- α, interleukin- (IL- 6, and intercellular adhesion molecule- (ICAM- 1 levels via western blot (WB assays. The results showed that flap viability was significantly higher in the hirudin-treated group, which showed a reduced inflammatory response compared with the control group. The Pp38/p38, pNF-κB p65/NF-κB p65, TNF-α, IL-6, and ICAM-1 levels in the hirudin-treated group were lower than those in the control group. The results demonstrated that hirudin could improve random skin flap viability and suggested that this effect maybe occurs by blocking the thrombin/proteinase-activated receptors (PARs/p38/NF-κB signalling pathway, thus decreasing the inflammatory response.

  4. Design of an active helicopter control experiment at the Princeton Rotorcraft Dynamics Laboratory

    Science.gov (United States)

    Marraffa, Andrew M.; Mckillip, R. M., Jr.

    1989-01-01

    In an effort to develop an active control technique for reducing helicopter vibrations stemming from the main rotor system, a helicopter model was designed and tested at the Princeton Rotorcraft Dynamics Laboratory (PRDL). A description of this facility, including its latest data acquisition upgrade, are given. The design procedures for the test model and its Froude scaled rotor system are also discussed. The approach for performing active control is based on the idea that rotor states can be identified by instrumenting the rotor blades. Using this knowledge, Individual Blade Control (IBC) or Higher Harmonic Control (HHC) pitch input commands may be used to impact on rotor dynamics in such a way as to reduce rotor vibrations. Discussed here is an instrumentation configuration utilizing miniature accelerometers to measure and estimate first and second out-of-plane bending mode positions and velocities. To verify this technique, the model was tested, and resulting data were used to estimate rotor states as well as flap and bending coefficients, procedures for which are discussed. Overall results show that a cost- and time-effective method for building a useful test model for future active control experiments was developed. With some fine-tuning or slight adjustments in sensor configuration, prospects for obtaining good state estimates look promising.

  5. Optical control of antibacterial activity

    NARCIS (Netherlands)

    Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

    2013-01-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly

  6. Optogenetic control of epileptiform activity

    DEFF Research Database (Denmark)

    Tønnesen, Jan; Sørensen, Andreas T; Deisseroth, Karl

    2009-01-01

    hyperpolarization of principal cortical neurons by NpHR is sufficient to curtail paroxysmal activity in transduced neurons and can inhibit stimulation train-induced bursting in hippocampal organotypic slice cultures, which represents a model tissue of pharmacoresistant epilepsy. This study demonstrates...

  7. The role of tip deflection on the thrust produced by rigid flapping fins

    Science.gov (United States)

    Huera-Huarte, Francisco; Gharib, Morteza

    2015-11-01

    It is well known that flexibility plays an important role in the propulsion performance and efficiency of oscillating fin based propulsion systems. Compliance is one of the aspects that has received more attention, as it seems to be a common feature in nature's flyers and swimmers. Active control strategies are also common in nature. We will show how by deflecting only the last 10% of length of a rigid fin, at the tip, the thrust can be changed dramatically. This can be thought as an alternative to passive flexibility for controlling very efficiently the momentum transfer in the wake and therefore the thrust generation when flapping. A series of experiments have been carried with a robotic fin that allowed the control of its flapping kinematics as well as the control of the motions of its tip independently. We will be showing situations in which the tip was kept at a certain fixed position during a power stroke, and others in which it moved either in-phase or out-of-phase with the fin. The observed thrust and wake dynamics will be discussed for all these situations. The authors would like to acknowledge the financial support provided by the Gordon and Betty Moore Foundation and by the Spanish Ministerio de Economia y competitividad (MINECO) through grant DPI2012-37904. Visiting Associate in Aerospace, California Institute of Technology.

  8. [Significance of abdominal wall CT-angiography in planning DIEA perforator flaps, TRAM flaps and SIEA flaps].

    Science.gov (United States)

    Fansa, H; Schirmer, S; Frerichs, O; Gehl, H B

    2011-04-01

    Muscle sparing TRAM flaps and DIEA perforator flaps are standard procedures for breast reconstruction. Recently CT-angiography has been established to evaluate perforator vessels pre-operatively. CT-angiography was introduced to our department in July 2009. In a retrospective analysis data of the last 20 patients (altogether 22 flaps) before CT-angiography introduction and the following 20 (also 22 flaps) patients after introduction of CT-angiography were analysed with regard to the ratio of TRAM to DIEP flaps, and the time required to raise the flaps. The same surgeon raised all flaps. As different surgeons performed dissection of the recipient site, anastomoses, and insertion of flaps, and patients received primary (with sentinel or complete lymphadenctomy) or secondary reconstructions, only the time required harvesting the flap was compared. Thus other influences on raising the flap were eliminated. DIEP flaps were harvested with one single perforator. If perfusion or was considered not to be safe via one single perforator a muscle sparing TRAM flap (ms2) was raised. Angiography was performed using a 64-slice multi-detector CT scanner. CT-angiography did not lead to an increased rate of DIEP flaps in relation to ms2-TRAM flaps. Harvesting time of all flap types with CT-angiography on average was 121 min, without CT-angiography 135 min. This was not significantly different. However, separate analysis of DIEP flaps and ms2-TRAM flaps revealed a significant advantage of CT-angiography based harvesting of DIEP flaps of 26 min: with CT-angiography 101 min vs. 127 min without CT-angiography (p<0.028). There were no significant differences for ms2-TRAM flaps. All scans showed course and branching, diameter and size of the inferior epigastric artery. If evident the superficial inferior epigastric artery (SIEA) was marked. Dosage was 292 mGy-606 mGy×cm dependent on body weight. CTDI was 6.8-14.7 mGy. CT-angiography is a reproducible and observer independent procedure

  9. Jacket substructure fatigue mitigation through active control

    DEFF Research Database (Denmark)

    Hanis, Tomas; Natarajan, Anand

    2014-01-01

    Active fatigue control system developed within DTU Wind Energy is used to enhance structural design by increasing lifetime or possible mass reduction.......Active fatigue control system developed within DTU Wind Energy is used to enhance structural design by increasing lifetime or possible mass reduction....

  10. Contrast-enhanced magnetic resonance angiography for preoperative imaging in DIEP flap breast reconstruction.

    Science.gov (United States)

    Schaverien, Mark V; Ludman, Catherine N; Neil-Dwyer, Jason; Perks, Graeme B; Akhtar, Nadeem; Rodrigues, Jeremy N; Benetatos, Konstantinos; Raurell, Anna; Rasheed, Tuabin; McCulley, Stephen J

    2011-07-01

    Contrast-enhanced magnetic resonance angiography has been shown to be very accurate for identifying the perforator size, location, and intramuscular course, and the associated venous system, without exposing the patient to ionizing radiation. This study reports the authors' experience using this imaging modality in a large patient series. A retrospective review of patients who had undergone preoperative contrast-enhanced magnetic resonance angiography followed by free abdominal flap breast reconstruction was conducted. The results of imaging were compared with intraoperative findings, and surgical outcomes were compared with scan data. The results were compared with control data in patients who did not undergo presurgical imaging. One hundred thirty-two patients underwent contrast-enhanced magnetic resonance angiography presurgical imaging, and the results were compared with 84 controls. The imaging was found to be accurate for evaluating the perforator anatomy for free abdominal flap planning, with a high concordance between imaging and intraoperative findings. Without presurgical angiography, the ratio of deep inferior epigastric perforator (DIEP) flap-to-free transverse rectus abdominis musculocutaneous flap harvest was 0.9:1; with presurgical imaging, the ratio was 1.6:1 (p angiography, there was a mean reduction in operating time of 26 minutes for unilateral DIEP flap harvest and 40 minutes for bilateral harvest, although these values were not significant. There was a significant reduction in the partial flap failure rate with preoperative imaging. Presurgical imaging using contrast-enhanced magnetic resonance angiography demonstrates a high concordance with intraoperative findings. In this series, the percentage of flaps that were raised as DIEP flaps was significantly increased in patients who underwent preoperative imaging, and the partial flap failure rate was significantly reduced. : Therapeutic, III.(Figure is included in full-text article.).

  11. Exotic wakes of flapping fins

    DEFF Research Database (Denmark)

    Schnipper, Teis

    We present, in 8 chapters, experiments on and numerical simulations of bodies flapping in a fluid. Focus is predominantly on a rigid foil, a model fish, that performs prescribed pitching oscillations where the foil rotates around its leading edge. In a flowing soap film is measured, with unpreced......We present, in 8 chapters, experiments on and numerical simulations of bodies flapping in a fluid. Focus is predominantly on a rigid foil, a model fish, that performs prescribed pitching oscillations where the foil rotates around its leading edge. In a flowing soap film is measured......-speed and the strength ratio of the vortices formed at the foil’s leading and trailing edge. The simulated vortex particles and measured thickness variations in the soap film show similar behaviour which indicates that the soap film provides a good approximation the flow of a two-dimensional incompressible and Newtonian...

  12. The Gradual Expansion Muscle Flap

    Science.gov (United States)

    2014-01-01

    struck an improvised explosive device, sustaining a III-B open tibia fracture with large anteromedial soft tissue defect and bone loss involving the...GEM flap technique. The average age was 26.0 years (range, 21–39 years), and all patients were male. Four patients had sustained their injuries as a...Biochem Cytol. 1961;9:493 495. 42. Sola OM, Christensen DL, Martin AW. Hypertrophy and hyperplasia of adult chicken anterior latissimus dorsi muscles

  13. The place of nasolabial flap in orofacial reconstruction: A review

    Directory of Open Access Journals (Sweden)

    Amin Rahpeyma

    2016-12-01

    Conclusion: Nasolabial flap is an old flap for reconstructive purposes. Over time different modifications have been introduced to expand its usage. Clear definition of the terms used with this flap is given.

  14. Congenital breast deformity reconstruction using perforator flaps.

    Science.gov (United States)

    Gautam, Abhinav K; Allen, Robert J; LoTempio, Maria M; Mountcastle, Timothy S; Levine, Joshua L; Allen, Robert J; Chiu, Ernest S

    2007-04-01

    Congenital breast deformities such as Poland syndrome, unilateral congenital hypoplasia, tuberous breast anomaly, and amastia pose a challenging plastic surgical dilemma. The majority of patients are young, healthy individuals who seek esthetic restoration of their breast deformities. Currently, both implant and autologous reconstructive techniques are used. This study focuses on our experience with congenital breast deformity patients who underwent reconstruction using a perforator flap. From 1994 to 2005, a retrospective chart review was performed on women who underwent breast reconstruction using perforator flaps to correct congenital breast deformities and asymmetry. Patient age, breast deformity type, perforator flap type, flap volume, recipient vessels, postoperative complications, revisions, and esthetic results were determined. Over an 11-year period, 12 perforator flaps were performed. All cases were for unilateral breast deformities. The patients ranged from 16 to 43 years of age. Six patients had undergone previous correctional surgeries. Eight (n = 8) flaps were used for correction of Poland syndrome and its associated chest wall deformities. Four (n = 4) flaps were used for correction of unilateral breast hypoplasia. In all cases, the internal mammary vessels were the recipient vessels of choice. No flaps were lost. No vein grafts were used. All patients were discharged on the fourth postoperative day. Complications encountered included seroma, hematoma, and nipple malposition. Revisional surgery was performed in 30% of the cases. Esthetic results varied from poor to excellent. Perforator flaps are an acceptable choice for patients with congenital breast deformities seeking autologous breast reconstruction. Deep inferior epigastric artery (DIEP) or superficial inferior epigastric artery (SIEA) flaps are performed when adequate abdominal tissue is available; however, many young patients have inadequate abdominal tissue, thus a GAP flap can be used

  15. A systematic review of flap fixation techniques in reducing seroma formation and its sequelae after mastectomy.

    Science.gov (United States)

    van Bastelaar, J; van Roozendaal, L; Granzier, R; Beets, G; Vissers, Y

    2018-01-01

    Seroma formation is a common complication after mastectomy. This review aims to elucidate which surgical techniques are most effective in reducing the dead space and therefore seroma formation in patients undergoing mastectomy. A literature search was performed to identify clinical studies comparing any form of flap fixation to conventional closure technique in patients undergoing mastectomy with or without axillary clearance. Studies were eligible for inclusion if outcome was described in terms of seroma formation and/or complications of seroma formation. Studies on animal research or breast reconstruction with tissue expanders or flap harvesting (latissimus dorsi) were excluded. A total of nine articles were eligible for inclusion. Five were retrospective studies and four were prospective. Retrospective and prospective studies have demonstrated the higher incidence of seroma formation in patients not undergoing mechanical flap fixation. The incidence of seroma-related complications in these studies vary. Four out of the nine studies demonstrate that patients undergoing flap fixation, need significantly fewer seroma aspirations. There are very few studies on the use of tissue glues preventing seroma formation. The scientific body of evidence favoring flap fixation after mastectomy is convincing. Mechanical flap fixation seems to reduce seroma formation and seroma aspiration after mastectomy. There are, however, no well-powered randomized controlled trials evaluating all aspects of seroma formation and its sequelae. Further research should elucidate whether flap fixation using sutures or tissue glue is superior.

  16. Active Flow Control on Bidirectional Rotors for Tidal MHK Applications

    Energy Technology Data Exchange (ETDEWEB)

    Shiu, Henry [Research Engineer; van Dam, Cornelis P. [Professor

    2013-08-22

    A marine and hydrokinetic (MHK) tidal turbine extracts energy from tidal currents, providing clean, sustainable electricity generation. In general, all MHK conversion technologies are confronted with significant operational hurdles, resulting in both increased capital and operations and maintenance (O&M) costs. To counter these high costs while maintaining reliability, MHK turbine designs can be simplified. Prior study found that a tidal turbine could be cost-effectively simplified by removing blade pitch and rotor/nacelle yaw. Its rotor would run in one direction during ebb and then reverse direction when the current switched to flood. We dubbed such a turbine a bidirectional rotor tidal turbine (BRTT). The bidirectional hydrofoils of a BRTT are less efficient than conventional hydrofoils and capture less energy, but the elimination of the pitch and yaw systems were estimated to reduce levelized cost of energy by 7.8%-9.6%. In this study, we investigated two mechanisms for recapturing some of the performance shortfall of the BRTT. First, we developed a novel set of hydrofoils, designated the yy series, for BRTT application. Second, we investigated the use of active flow control via microtabs. Microtabs are small deployable/retractable tabs, typically located near the leading or trailing edge of an air/hydrofoil with height on the order of the boundary layer thickness (1% - 2% of chord). They deploy approximately perpendicularly to the foil surface and, like gurney flaps and plain flaps, globally affect the aerodynamics of the airfoil. By strategically placing microtabs and selectively deploying them based on the direction of the inflow, performance of a BRTT rotor can be improved while retaining bidirectional operation. The yy foils were computationally designed and analyzed. They exhibited better performance than the baseline bidirectional foil, the ellipse. For example, the yyb07cn-180 had 14.7% higher (l/d)max than an ellipse of equal thickness. The yyb07cn

  17. Effect’s of Danazol use on the viability of dorsal rat flap

    Directory of Open Access Journals (Sweden)

    Altan Yücetaş

    2009-03-01

    Full Text Available Repaire of large skin defects is one of the most challenging problem on reconstructive surgery. As known that, the most suitable functional and aesthetic way for flaps are preferrable for aesthetic and functional results. But flaps which used for large skin defects lenght are limited. When the flap’s height lenghtens, flap surviving decreases. In this situation, necrosis and tissue lost is encorded. To prevent this problems, symphatolytic agents and anticoagulans which increases blood flow and changes reolytic property of blood are used. Moreover, cell membrane stabilization is attempted to be maintained.Danazol is antiinflammatory agent in the treatment of endometriosis and it has weak gonadotropic activity. In this study twenty female, adult Sprague-Dawley rat were included. Danazol can decrease random pattern skin flap necrosis due to the fact that danazol has anticoagulant and anti-inflammation property. Danazol may used for increasing survival of flap by decresing development of necrosis on distal part of random pattern skin flap. In this article, we mentioned antiinflammatory mechanism of danazol and influence viability of flap.

  18. Aeroelastic Stability of a 2D Airfoil Section equipped with a Trailing Edge Flap

    DEFF Research Database (Denmark)

    Bergami, Leonardo

    Recent studies conclude that important reduction of the fatigue loads encountered by a wind turbine blade can be achieved using a deformable trailing edge control system. The focus of the current work is to determine the effect of this flap-like system on the aeroelastic stability of a 2D airfoil...... section. A simulation tool is implemented to predict the flow speed at which a flap equipped section may become unstable, either due to flutter or divergence. First, the stability limits of the airfoil without flap are determined, and, in the second part of the work, a deformable trailing edge flap...... of the pressure difference between the two sides of the airfoil. The stability of the aeroservoelastic system in a defined equilibrium state, and for a given flow speed, is then determined by solving an eigenvalue problem. Results show that the trailing edge control system modifies significantly the stability...

  19. Activities of the control services; Activites des services du controle

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This paper summarizes the control activities of the technical service of electric power and big dams: annual examinations, administrative instructions (draining, floods, granting renewal), decennial examinations etc. (J.S.)

  20. Simulation of Moving Trailing Edge Flaps on a Wind Turbine Blade using a Navier-Stokes based Immersed Boundary Method

    DEFF Research Database (Denmark)

    Behrens, Tim

    As the rotor diameter of wind turbines increases, turbine blades with distributed aerodynamic control surfaces promise significant load reductions. Therefore, they are coming into focus in relation to research in academia and industry. Trailing edge flaps are of particular interest in terms of co...... field around trailing edge flaps.......As the rotor diameter of wind turbines increases, turbine blades with distributed aerodynamic control surfaces promise significant load reductions. Therefore, they are coming into focus in relation to research in academia and industry. Trailing edge flaps are of particular interest in terms...... trailing edge flap geometries in two and three dimensions. Validation cases were presented for the circular cylinder in a Cartesian mesh topology as well as in a topology similar to a standard body fitted mesh. To simulate trailing edge flaps, a hybrid approach was developed that modeled only the moving...

  1. A split mouth randomized controlled study to evaluate the adjunctive effect of platelet-rich fibrin to coronally advanced flap in Miller′s class-I and II recession defects

    Directory of Open Access Journals (Sweden)

    Rajan Padma

    2013-01-01

    Full Text Available Background: There are various techniques developed to treat the exposed roots, a recent innovation in dentistry is the use of second generation platelet concentrate which is an autologous platelet-rich fibrin gel (PRF with growth factors and cicatricial properties for root coverage procedures. Therefore, the present research was undertaken to study the additional benefits of PRF when used along with coronally advanced flap (CAF. Materials and Methods: Total of 15 systemically healthy subjects presenting bilateral isolated Miller′s class I and II recession were enrolled into the study. Each patient was randomly treated with a combination of CAF along with a platelet-rich fibrin (PRF membrane on the test site and CAF alone on the control site. Recession depth, clinical attachment level (CAL, and width of keratinized gingiva (WKG were compared with baseline at 1, 3, and 6 months between test and control sites. Results: Mean percentage root coverage in the test group after 1, 3, and 6 months was 34.58, 70.73, and 100, respectively. Differences between the control and test groups were statistically significant. This study also showed a statistically significant increase in WKG in the test group (2.94 ± 0.77 at baseline to 5.38 ± 1.67 at 6 months. Conclusion: CAF is a predictable treatment for isolated Miller′s class I and II recession defects. The addition of PRF membrane with CAF provides superior root coverage with additional benefits of gain in CAL and WKG at 6 months postoperatively.

  2. Innovation in the planning of V-Y rotation advancement flaps: A template for flap design

    Directory of Open Access Journals (Sweden)

    Utku Can Dölen

    2018-01-01

    Full Text Available Local flaps exhibit excellent color matching that no other type of flap can compete with. Moreover, surgery using a local flap is easier and faster than surgery using a distant or free flap. However, local flaps can be much more difficult to design. We designed 2 templates to plan a V-Y rotation advancement flap. The template for a unilateral V-Y rotation advancement flap was used on the face (n=5, anterior tibia (n=1, posterior axilla (n=1, ischium (n=1, and trochanter (n=2. The template for a bilateral flap was used on the sacrum (n=8, arm (n=1, and anterior tibia (n=1. The causes of the defects were meningocele (n=3, a decubitus ulcer (n=5, pilonidal sinus (n=3, and skin tumor excision (n=10. The meningocele patients were younger than 8 days. The mean age of the adult patients was 50.4 years (range, 19–80 years. All the donor areas of the flaps were closed primarily. None of the patients experienced wound dehiscence or partial/total flap necrosis. The templates guided surgeons regarding the length and the placement of the incision for a V-Y rotation advancement flap according to the size of the wound. In addition, they could be used for the training of residents.

  3. Innovation in the planning of V-Y rotation advancement flaps: A template for flap design.

    Science.gov (United States)

    Dölen, Utku Can; Koçer, Uğur

    2018-01-01

    Local flaps exhibit excellent color matching that no other type of flap can compete with. Moreover, surgery using a local flap is easier and faster than surgery using a distant or free flap. However, local flaps can be much more difficult to design. We designed 2 templates to plan a V-Y rotation advancement flap. The template for a unilateral V-Y rotation advancement flap was used on the face (n=5), anterior tibia (n=1), posterior axilla (n=1), ischium (n=1), and trochanter (n=2). The template for a bilateral flap was used on the sacrum (n=8), arm (n=1), and anterior tibia (n=1). The causes of the defects were meningocele (n=3), a decubitus ulcer (n=5), pilonidal sinus (n=3), and skin tumor excision (n=10). The meningocele patients were younger than 8 days. The mean age of the adult patients was 50.4 years (range, 19-80 years). All the donor areas of the flaps were closed primarily. None of the patients experienced wound dehiscence or partial/total flap necrosis. The templates guided surgeons regarding the length and the placement of the incision for a V-Y rotation advancement flap according to the size of the wound. In addition, they could be used for the training of residents.

  4. Controls on fire activity over the Holocene

    Science.gov (United States)

    Kloster, S.; Brucher, T.; Brovkin, V.; Wilkenskjeld, S.

    2015-05-01

    Changes in fire activity over the last 8000 years are simulated with a global fire model driven by changes in climate and vegetation cover. The changes were separated into those caused through variations in fuel availability, fuel moisture or wind speed, which react differently to changes in climate. Disentangling these controlling factors helps in understanding the overall climate control on fire activity over the Holocene. Globally the burned area is simulated to increase by 2.5% between 8000 and 200 cal yr BP, with larger regional changes compensating nearly evening out on a global scale. Despite the absence of anthropogenic fire ignitions, the simulated trends in fire activity agree reasonably well with continental-scale reconstructions from charcoal records, with the exception of Europe. For some regions the change in fire activity is predominantly controlled through changes in fuel availability (Australia monsoon, Central America tropics/subtropics). For other regions changes in fuel moisture are more important for the overall trend in fire activity (North America, Sub-Saharan Africa, Europe, Asia monsoon). In Sub-Saharan Africa, for example, changes in fuel moisture alone lead to an increase in fire activity between 8000 and 200 cal yr BP, while changes in fuel availability lead to a decrease. Overall, the fuel moisture control is dominating the simulated fire activity for Sub-Saharan Africa. The simulations clearly demonstrate that both changes in fuel availability and changes in fuel moisture are important drivers for the fire activity over the Holocene. Fuel availability and fuel moisture do, however, have different climate controls. As such, observed changes in fire activity cannot be related to single climate parameters such as precipitation or temperature alone. Fire models, as applied in this study, in combination with observational records can help in understanding the climate control on fire activity, which is essential to project future fire

  5. Monitoring by Control Technique - Activated Carbon Adsorber

    Science.gov (United States)

    Stationary source emissions monitoring is required to demonstrate that a source is meeting the requirements in Federal or state rules. This page is about Activated Carbon Adsorber control techniques used to reduce pollutant emissions.

  6. Unraveling HIV protease flaps dynamics by Constant pH Molecular Dynamics simulations.

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. DSP Control of Line Hybrid Active Filter

    DEFF Research Database (Denmark)

    Dan, Stan George; Benjamin, Doniga Daniel; Magureanu, R.

    2005-01-01

    Active Power Filters have been intensively explored in the past decade. Hybrid active filters inherit the efficiency of passive filters and the improved performance of active filters, and thus constitute a viable improved approach for harmonic compensation. In this paper a parallel hybrid filter ...... active filter. Simulation and experimental results obtained in laboratory confirmed the validity and effectiveness of the control.......Active Power Filters have been intensively explored in the past decade. Hybrid active filters inherit the efficiency of passive filters and the improved performance of active filters, and thus constitute a viable improved approach for harmonic compensation. In this paper a parallel hybrid filter...... is studied for current harmonic compensation. The hybrid filter is formed by a single tuned Le filter and a small-rated power active filter, which are directly connected in series without any matching transformer. Thus the required rating of the active filter is much smaller than a conventional standalone...

  8. Simulations on Active Fan Noise Control

    OpenAIRE

    Fischer, Helen

    2012-01-01

    International audience; Noise reduction by active noise control in jet engines and its prediction is of high interest, since the acoustic goals of flightpath 2050 can hardly be achieved by passive acoustic treatments. Numerous former test campaigns showed that significant noise reduction is possible by active noise control. Simulations are needed for further understanding of test results and in order to predict the noise reduction and possibly impact on the performance of future jet engines. ...

  9. Aeroservoelastic stability of a 2D airfoil section equipped with a trailing edge flap

    Energy Technology Data Exchange (ETDEWEB)

    Bergami, Leonardo

    2008-11-15

    Recent studies conclude that important reduction of the fatigue loads encountered by a wind turbine blade can be achieved using a deformable trailing edge control system. The focus of the current work is to determine the effect of this flap-like system on the aeroelastic stability of a 2D airfoil section. A simulation tool is implemented to predict the flow speed at which a flap equipped section may become unstable, either due to flutter or divergence. First, the stability limits of the airfoil without flap are determined, and, in the second part of the work, a deformable trailing edge flap is applied. Stability is investigated for the uncontrolled flap, and for three different control algorithms. The three controls are tuned for fatigue load alleviation and they are based on, respectively, measurement of the heave displacement and velocity, measurement of the local angle of attack, measurement of the pressure difference between the two sides of the airfoil. The stability of the aeroservoelastic system in a defined equilibrium state, and for a given flow speed, is then determined by solving an eigenvalue problem. Results show that the trailing edge control system modifies significantly the stability limits of the section. In the investigated case, increased flutter limits are reported when the elastic flap is left without control, whereas, by applying any of the control algorithms, the flutter velocity is reduced. Nevertheless, only in the heave control case the flutter limit becomes critically close to normal operation flow speeds. Furthermore, a marked dependence of the stability limits on the control gain is also observed and, by tuning the gain parameters, flutter and divergence can be suppressed for flow speed even above the flutter velocity encountered with uncontrolled flap. (author)

  10. The Lateral Thigh Perforator Flap for Autologous Breast Reconstruction: A Prospective Analysis of 138 Flaps.

    Science.gov (United States)

    Tuinder, Stefania M H; Beugels, Jop; Lataster, Arno; de Haan, Michiel W; Piatkowski, Andrzej; Saint-Cyr, Michel; van der Hulst, René R W J; Allen, Robert J

    2018-02-01

    The septocutaneous tensor fasciae latae or lateral thigh perforator flap was previously introduced by the authors' group as an alternative flap for autologous breast reconstruction when the abdomen is not suitable as a donor site. The authors analyzed their experience with the lateral thigh perforator flap and present the surgical refinements that were introduced. A prospective study was conducted of all lateral thigh perforator flap breast reconstructions performed since September of 2012. Patient demographics, operative details, complications, and flap reexplorations were recorded. Preoperative imaging with magnetic resonance angiography was performed in all patients. Surgical refinements introduced during this study included limitation of the flap width and the use of quilting sutures at the donor site. A total of 138 lateral thigh perforator flap breast reconstructions were performed in 86 consecutive patients. Median operative times were 277 minutes (range, 196 to 561 minutes) for unilateral procedures and 451 minutes (range, 335 to 710 minutes) for bilateral. Median flap weight was 348 g (range, 175 to 814 g). Two total flap losses (1.4 percent) were recorded, and 11 flaps (8.0 percent) required reexploration, which resulted in viable flaps. The incidence of donor-site complications was reduced significantly after the surgical refinements were introduced. Wound problems decreased from 40.0 percent to 6.3 percent, seroma decreased from 25.0 percent to 9.5 percent, and infection decreased from 27.5 percent to 9.5 percent. The lateral thigh perforator flap is an excellent option for autologous breast reconstruction, with minimal recipient-site complications. The surgical refinements resulted in a significant reduction of donor-site complications. Therefore, the lateral thigh perforator flap is currently the authors' second choice after the deep inferior epigastric artery perforator flap. Therapeutic, IV.

  11. Reconstruction of Complex Facial Defects Using Cervical Expanded Flap Prefabricated by Temporoparietal Fascia Flap.

    Science.gov (United States)

    Zhang, Ling; Yang, Qinghua; Jiang, Haiyue; Liu, Ge; Huang, Wanlu; Dong, Weiwei

    2015-09-01

    Reconstruction of complex facial defects using cervical expanded flap prefabricated by temporoparietal fascia flap. Complex facial defects are required to restore not only function but also aesthetic appearance, so it is vital challenge for plastic surgeons. Skin grafts and traditional flap transfer cannot meet the reconstructive requirements of color and texture with recipient. The purpose of this sturdy is to create an expanded prefabricated temporoparietal fascia flap to repair complex facial defects. Two patients suffered severe burns on the face underwent complex facial resurfacing with prefabricated cervical flap. The vasculature of prefabricated flap, including the superficial temporal vessel and surrounding fascia, was used as the vascular carrier. The temporoparietal fascia flap was sutured underneath the cervical subcutaneous tissue, and expansion was begun in postoperative 1 week. After 4 to 6 months of expansion, the expander was removed, facial scars were excised, and cervical prefabricated flap was elevated and transferred to repair the complex facial defects. Two complex facial defects were repaired successfully by prefabricated temporoparietal fascia flap, and prefabricated flaps survived completely. On account of donor site's skin was thinner and expanded too fast, 1 expanded skin flap was rupture during expansion, but necrosis was not occurred after the 2nd operation. Venous congestion was observed in 1 patient, but after dressing, flap necrosis was not happened. Donor site was closed primarily. Postoperative follow-up 6 months, the color, texture of prefabricated flap was well-matched with facial skin. This method of expanded prefabricated flap may provide a reliable solution to the complex facial resurfacing.

  12. Median forehead flap - beyond classic indication

    Directory of Open Access Journals (Sweden)

    Cristian R. Jecan

    2016-11-01

    Full Text Available Introduction. The paramedian forehead flap is one of the best options for reconstruction of the median upper two-thirds of the face due to its vascularity, color, texture match and ability to resurface all or part of the reconstructed area. The forehead flap is the gold standard for nasal soft tissue reconstruction and the flap of choice for larger cutaneous nasal defects having a robust pedicle and large amount of tissue. Materials and Methods. We are reporting a clinical series of cutaneous tumors involving the nose, medial canthus, upper and lower eyelid through a retrospective review of 6 patients who underwent surgical excision of the lesion and primary reconstruction using a paramedian forehead flap. Results. The forehead flap was used for total nose reconstruction, eyelids and medial canthal reconstruction. All flaps survived completely and no tumor recurrence was seen in any of the patients. Cosmetic and functional results were favorable. Conclusions. The forehead flap continues to be one of the best options for nose reconstruction and for closure of surgical defects of the nose larger than 2 cm. Even though is not a gold standard, median forehead flap can be an advantageous technique in periorbital defects reconstruction.

  13. Analysis of tail effects in flapping flight

    NARCIS (Netherlands)

    Tay, W.B.; Bijl, H.; Van Oudheusden, B.W.

    2011-01-01

    Numerical simulations have been performed to examine the interference effects between an upstream flapping airfoil and a downstream stationary airfoil in a tandem configuration at a Reynolds number of 1000, which is around the regime of small flapping micro aerial vehicles. The objective is to

  14. POSTERIOR INTEROSSEOUS FLAP IN PEDIATRIC HAND RECONSTRUCTIONS

    Directory of Open Access Journals (Sweden)

    I. O. Golubev

    2014-01-01

    Full Text Available Purpose: to assess early and long-term results of the pediatric hand reconstructions with posterior interosseous flap, including those in children younger than 3 years old. Materials and methods: results of the hand reconstructions with posterior interosseous artery reverse flap were studied in 10 children (4 males and 6 females aged from 1 year and 1 month to 13 years old. In 4 cases flap coverage were performed due to acquired posttraumatic hand deformity, in 6 cases reconstruction was assumed for congenital hand deformities. Combined procedures consisted of posterior interosseous artery flap coverage and other types of microsurgical reconstructions were suggested in 4 patients. Preoperative color doppler visualization of the posterior interosseous vessels were mandatory. All flaps were risen under 3.5x-4.5x magnification. Results: all flaps survived completely in 3 weeks postoperatively. There were no postoperative complications such as flap’s arterial or venous insufficiency, deep infection, or posterior interosseous nerve palsy. Nearly whole group (9 of 10 of patients and/or their parents were satisfied with the esthetic view of the reconstructed hand and donor site of the forearm 1 year postoperatively. Conclusion: posterior interosseous flap is a reliable and versatile option in pediatric hand reconstructions, providing excellent skin coverage with good color match and texture. Preservation of major vascular bundles of the forearm (radial and ulnar arteries during flap harvest gives a possibility to perform a simultaneous microsurgical reconstructions of the hand (e.g. free toe transfer.

  15. Active load control techniques for wind turbines.

    Energy Technology Data Exchange (ETDEWEB)

    van Dam, C.P. (University of California, Davis, CA); Berg, Dale E.; Johnson, Scott J. (University of California, Davis, CA)

    2008-07-01

    This report provides an overview on the current state of wind turbine control and introduces a number of active techniques that could be potentially used for control of wind turbine blades. The focus is on research regarding active flow control (AFC) as it applies to wind turbine performance and loads. The techniques and concepts described here are often described as 'smart structures' or 'smart rotor control'. This field is rapidly growing and there are numerous concepts currently being investigated around the world; some concepts already are focused on the wind energy industry and others are intended for use in other fields, but have the potential for wind turbine control. An AFC system can be broken into three categories: controls and sensors, actuators and devices, and the flow phenomena. This report focuses on the research involved with the actuators and devices and the generated flow phenomena caused by each device.

  16. Active spatial control of plasmonic fields

    NARCIS (Netherlands)

    Gjonaj, Bergin; Aulbach, Jochen; Aulbach, Jochen; Johnson, Patrick M.; Mosk, Allard; Kuipers, L.; Kuipers, L.; Lagendijk, Ad; Lagendijk, Aart

    2011-01-01

    The field of plasmonics1 offers a route to control light fields with metallic nanostructures through the excitation of surface plasmon polaritons2. These surface waves, bound to a metal dielectric interface, can tightly confine electromagnetic energy3. Active control over surface plasmon polaritons

  17. Development of an Active Flow Control Technique for an Airplane High-Lift Configuration

    Science.gov (United States)

    Shmilovich, Arvin; Yadlin, Yoram; Dickey, Eric D.; Hartwich, Peter M.; Khodadoust, Abdi

    2017-01-01

    This study focuses on Active Flow Control methods used in conjunction with airplane high-lift systems. The project is motivated by the simplified high-lift system, which offers enhanced airplane performance compared to conventional high-lift systems. Computational simulations are used to guide the implementation of preferred flow control methods, which require a fluidic supply. It is first demonstrated that flow control applied to a high-lift configuration that consists of simple hinge flaps is capable of attaining the performance of the conventional high-lift counterpart. A set of flow control techniques has been subsequently considered to identify promising candidates, where the central requirement is that the mass flow for actuation has to be within available resources onboard. The flow control methods are based on constant blowing, fluidic oscillators, and traverse actuation. The simulations indicate that the traverse actuation offers a substantial reduction in required mass flow, and it is especially effective when the frequency of actuation is consistent with the characteristic time scale of the flow.

  18. Recovery of infraorbital nerve function after zygomaticomaxillary cheek pedicled flap.

    Science.gov (United States)

    Giannì, A B; Biglioli, F; Brevi, B; Brusati, R

    1995-10-01

    The zygomaticomaxillary cheek pedicled flap (ZMCF) involves the intentional section of the infraorbital nerve to reflect the flap laterally in order to give access to the rhinopharynx, clivus and upper cervical spine. The aim of this trial was to examine the recovery of sensation of the infraorbital nerve, both quantitatively (touch sensation, localisation test, two-point discrimination) and qualitatively (sharp/blunt test, temperature sensation, pain sensitivity, dental sensitivity) in 7 patients, at least 12 months after surgery. In each patient, four cutaneous areas (lower eyelid, nose ala, upper lip, cheek) and the upper vestibulum were tested. Results of each test in all the examined areas were evaluated and compared with the data obtained on the nonoperated side (control side). Results of neurosensory tests indicated good recovery of sensation with little difference in comparison with the control side, showing that the functional consequence of ZMCF should actually be considered only as a transitory event.

  19. Modeling and control of active twist aircraft

    Science.gov (United States)

    Cramer, Nicholas Bryan

    The Wright Brothers marked the beginning of powered flight in 1903 using an active twist mechanism as their means of controlling roll. As time passed due to advances in other technologies that transformed aviation the active twist mechanism was no longer used. With the recent advances in material science and manufacturability, the possibility of the practical use of active twist technologies has emerged. In this dissertation, the advantages and disadvantages of active twist techniques are investigated through the development of an aeroelastic modeling method intended for informing the designs of such technologies and wind tunnel testing to confirm the capabilities of the active twist technologies and validate the model. Control principles for the enabling structural technologies are also proposed while the potential gains of dynamic, active twist are analyzed.

  20. Self-Propulsion of a Flapping Airfoil Using Cyber-Physical Fluid Dynamics

    Science.gov (United States)

    Young, Jay; Asselin, Daniel; Williamson, C. H. K.

    2017-11-01

    The fluid dynamics of biologically-inspired flapping propulsion provides a fertile testing ground for the field of unsteady aerodynamics, serving as important groundwork for the design and development of underwater vehicles and micro air vehicles (MAVs). These technologies can provide low cost, compact, and maneuverable means for terrain mapping, search and rescue operations, and reconnaissance. However, most laboratory experiments and simulations have been conducted using tethered airfoils with an imposed freestream velocity, which does not necessarily reflect the conditions under which an airfoil employed as a propulsor would operate. Using a closed-loop force-feedback control system, defined as Cyber-Physical Fluid Dynamics, or CPFD (Mackowski & Williamson 2011, 2015, & 2016), we allow a flapping airfoil to fly forward freely, achieving an equilibrium velocity at which thrust and drag are balanced. We study a combination of actively and passively controlled pitching and heaving dynamics in order to find motions that minimize the energy expended per distance traveled by the propulsion system. This work was supported by the National Science Foundation and the Air Force Office of Scientific Research Grant No. FA9550-15-1-0243, monitored by Dr. Douglas Smith.

  1. Blood flow autoregulation in pedicled flaps

    DEFF Research Database (Denmark)

    Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

    2009-01-01

    INTRODUCTION: Clinical work on the blood perfusion in skin and muscle flaps has suggested that some degree of blood flow autoregulation exists in such flaps. An autoregulatory mechanism would enable the flap to protect itself from changes in the perfusion pressure. The purpose of the present study...... was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......-type calcium channel blocker nimodipine and the vasodilator papaverine. MATERIAL AND METHODS: Pedicled flaps were raised in pigs. Flow in the pedicle was reduced by constriction of the feed artery (n=34). A transit time flow probe measured the effect on blood flow continuously. Following this, three different...

  2. Fasciocutaneous flap for vaginal and perineal reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.N.; Whetzel, T.; Mathes, S.J.; Vasconez, L.O.

    1987-07-01

    A skin and fascia flap from the medial thigh is proposed for vaginal and perineal reconstruction. Dissection, vascular injection, and radiographs of 20 fresh cadaver limbs uniformly demonstrated the presence of a communicating suprafascial vascular plexus in the medial thigh. Three to four nonaxial vessels were consistently found to enter the proximal plexus from within 5 cm of the perineum. Preservation of these vessels permitted reliable elevation of a 9 X 20 cm fasciocutaneous flap without using the gracilis muscle as a vascular carrier. Fifteen flaps in 13 patients were used for vaginal replacement and coverage of vulvectomy, groin, and ischial defects. Depending on the magnitude of the defect, simultaneous and independent elevation of the gracilis muscle provided additional vascularized coverage as needed. Our experience indicates that the medial thigh fasciocutaneous flap is a durable, less bulky, and potentially sensate alternative to the gracilis musculocutaneous flap for vaginal and perineal reconstruction.

  3. Control of nucleus accumbens activity with neurofeedback.

    Science.gov (United States)

    Greer, Stephanie M; Trujillo, Andrew J; Glover, Gary H; Knutson, Brian

    2014-08-01

    The nucleus accumbens (NAcc) plays critical roles in healthy motivation and learning, as well as in psychiatric disorders (including schizophrenia and attention deficit hyperactivity disorder). Thus, techniques that confer control of NAcc activity might inspire new therapeutic interventions. By providing second-to-second temporal resolution of activity in small subcortical regions, functional magnetic resonance imaging (fMRI) can resolve online changes in NAcc activity, which can then be presented as "neurofeedback." In an fMRI-based neurofeedback experiment designed to elicit NAcc activity, we found that subjects could increase their own NAcc activity, and that display of neurofeedback significantly enhanced their ability to do so. Subjects were not as capable of decreasing their NAcc activity, however, and enhanced control did not persist after subsequent removal of neurofeedback. Further analyses suggested that individuals who recruited positive aroused affect were better able to increase NAcc activity in response to neurofeedback, and that NAcc neurofeedback also elicited functionally correlated activity in the medial prefrontal cortex. Together, these findings suggest that humans can modulate their own NAcc activity and that fMRI-based neurofeedback may augment their efforts. The observed association between positive arousal and effective NAcc control further supports an anticipatory affect account of NAcc function. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Active fault diagnosis by controller modification

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, Hans Henrik

    2010-01-01

    Two active fault diagnosis methods for additive or parametric faults are proposed. Both methods are based on controller reconfiguration rather than on requiring an exogenous excitation signal, as it is otherwise common in active fault diagnosis. For the first method, it is assumed that the system...... in a way that guarantees the continuity of transition and global stability using a recent result on observer parameterization. An illustrative example inspired by a field study of a drag racing vehicle is given. For the second method, an active fault diagnosis method for parametric faults is proposed...... considered is controlled by an observer-based controller. The method is then based on a number of alternate observers, each designed to be sensitive to one or more additive faults. Periodically, the observer part of the controller is changed into the sequence of fault sensitive observers. This is done...

  5. Active vibration control of civil structures

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.; Baker, W.; Fales, J.; Shevitz, D.

    1996-11-01

    This is a final report of a one year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Active vibration control (AVC) of structural and mechanical systems is one of the rapidly advancing areas of engineering research. The multifaceted nature of AVC covers many disciplines, such as sensors and instrumentation, numerical modeling, experimental mechanics, and advanced power systems. This work encompassed a review of the literature on active control of structures focusing both on active control hardware and on control algorithms, a design of an isolation systems using magneto-rheological fluid-filled (MRF) dampers and numerical simulations to study the enhanced vibration mitigation effects of this technology.

  6. THE CONTROL AND EVALUATION OF PROMOTIONAL ACTIVITIES

    Directory of Open Access Journals (Sweden)

    Felicia Sabou

    2012-01-01

    Full Text Available The paper focused on importance and benefits of control and evaluation of marketing activities. The control of efficiency review the assessment of the resources for marketing activity, checking also the efficiency of the human resources, advertising, promotion activities and distribution activities. In the analyse of human resources the most important ratio are: the average of costumers visits on a day, the number of custom order received from 100 visits, the number of new customers from a period, the number of lost customers from a period, the marketing human expenditures from all the sales.The strategic control is made to check if the objectives and the company strategy are adapted to the marketing environment.

  7. A study of the use of the supraclavicular artery flap for resurfacing of head, neck, and upper torso defects

    Directory of Open Access Journals (Sweden)

    Telang Parag

    2009-01-01

    Full Text Available The head and neck region is an aesthetically demanding area to resurface because of its high visibility. Tissue defects in this area often require distant flaps or free flaps to achieve an aesthetically acceptable result. The use of the Supraclavicular artery flap represents an extremely versatile and useful option for the resurfacing of head, neck and upper torso defects. Furthermore, islanding the flap gives it a wide arc of rotation and the color and texture match is superior to that of free flaps harvested from distant sites. In our study, we used the flap (both unexpanded and expanded predominantly for resurfacing neck defects resulting from the release of post-burn contractures. However, its applicability in other indications would also be similar. Except one, all our flaps survived almost completely and the post-operative morbidity was very low. We conclude that the supraclavicular artery flap not only provides a reasonably good color and texture match but also maintains the multi-directional activity in the neck region.

  8. Investigation of Boundary-Layer Control to Improve the Lift and Drag Characteristics of the NACA 652-415 Airfoil Section with Double Slotted and Plain Flaps

    National Research Council Canada - National Science Library

    Horton, Elmer

    1950-01-01

    A two-dimensional wind-tunnel investigation has been made of the relative effectiveness of two methods of boundary-layer control in increasing the maximum lift coefficient of an NACA airfoil section...

  9. [Clinical applications of the anterolateral skin flap and the fascial flap in the lower leg].

    Science.gov (United States)

    Feng, D; Chen, P; Feng, D

    1999-07-01

    To introduce the applied anatomy, operative method and clinical application of the anterolateral skin flap and fascial flap of the lower leg. Anatomic dissection was performed on 14 adult cadavers' legs and one amputated lower limb. The origin, course and distribution of cutaneous branches of the superficial peroneal vessels were traced. Four types of anterolateral flaps were designed in the lower leg including the island skin flap, the island fascial flap, the rectangular flap, and the cross-leg flap. Since 1988, twenty-six cases of leg defects(21 patients), chronic osteomyelitis of the tibia(3 cases) and defects on the back of the opposite heel and ankle(2 cases) were treated with the operative methods. All the flaps survived. Primary healing occurred in 23 and secondary in 3 cases. Twenty cases were followed-up for 4 months to 5 years. The flaps were growing well, the tibia fracture healed 3 months after the treatment and the chronic osteomyelitis of tibia had no recurrence. This flap is a useful method for repairing various defects in the leg and adjacent regions. It is simple, safe and reliable in manipulation and has minimal influence to the donor site.

  10. Total endoscopic free flap harvest of a serratus anterior fascia flap for microsurgical lower leg reconstruction

    Directory of Open Access Journals (Sweden)

    Erdmann, Alfons

    2014-04-01

    Full Text Available [english] Background: A tremendous number of free flaps have been developed in the past. As the surgical result depends not only on a successful flap transfer but also on the harvest, this paper details the procedures for undertaking the first total endoscopic harvest of a serratus fascia flap for free flap transplantation to the lower leg. Patient and methods: In September 2012 we performed the first total endoscopic serratus anterior fascia free flap harvest. The incision of 2.5 cm length was made 10 cm in front of anterior muscle border of the latissimus dorsi at level with the midthorax. After insertion of a flexible laparoscopic single port system we started CO gas insufflation. We used this setting to meticulously prepare a neo cavity between atissimus dorsi and M. serratus anterior. The vessels were dissected and the thoraco-dorsal nerve was separated. With a second auxiliary incision we used a clamp to support the raising of the fascia flap from the underlying muscle. Finally we clipped the vessels to the latissimus dorsi muscle and the flap vessels at the Arteria and Vena axillaris. The flap was extracted via the 2.5 cm incision.Results: We were able to perform a total endoscopic harvest of a serratus fascia flap for free flap reconstruction of soft tissues. With this new operative technique we were able to avoid a long skin incision, which in our view lowers the morbidity at the harvest area.Conclusion: We describe a new method for the total endoscopic harvest of the serratus fascia flap for free flap transfer. The flap was harvested within reasonable time and following surgery leaves the patient with minimal donor site morbidity compared to the open technique.

  11. Hydrodynamic schooling of flapping swimmers

    Science.gov (United States)

    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.

  12. Simulation studies for multichannel active vibration control

    Science.gov (United States)

    Prakash, Shashikala; Balasubramaniam, R.; Praseetha, K. K.

    2003-10-01

    Traditional approach to vibration control uses passive techniques, which are relatively large, costly and ineffective at low frequencies. Active Vibration Control (AVC) is used to overcome these problems & in AVC additional sources (secondary) are used to cancel vibration from primary source based on the principle of superposition theorem Since the characteristics of the vibration source and environment are time varying, the AVC system must be adaptive. Adaptive systems have the ability to track time varying disturbances and provide optimal control over a much broader range of conditions than conventional fixed control systems. In multi channel AVC vibration fields in large dimensions are controlled & is more complicated. Therefore to actively control low frequency vibrations on large structures, multi channel AVC requires a control system that uses multiple secondary sources to control the vibration field simultaneously at multiple error sensor locations. The error criterion that can be directly measured is the sum of squares of outputs of number of sensors. The adaptive algorithm is designed to minimize this & the algorithm implemented is the "Multiple error LMS algorithm." The best known applications of multiple channel FXLMS algorithm is in real time AVC and system identification. More wider applications are in the control of propeller induced noise in flight cabin interiors. In the present paper the results of simulation studies carried out in MATLAB as well as on TMS320C32 DSP processor will be brought out for a two-channel case.

  13. A Flap Endonuclease (TcFEN1) Is Involved in Trypanosoma cruzi Cell Proliferation, DNA Repair, and Parasite Survival.

    Science.gov (United States)

    Ponce, Ivan; Aldunate, Carmen; Valenzuela, Lucia; Sepúlveda, Sofia; Garrido, Gilda; Kemmerling, Ulrike; Cabrera, Gonzalo; Galanti, Norbel

    2017-07-01

    FLAP endonucleases (FEN) are involved both in DNA replication and repair by processing DNA intermediaries presenting a nucleotide flap using its phosphodiesterase activity. In spite of these important functions in DNA metabolism, this enzyme was not yet studied in Trypanosomatids. Trypanosoma cruzi, the ethiological agent of Chagas disease, presents two dividing cellular forms (epimastigote and amastigote) and one non-proliferative, infective form (trypomastigote). The parasite survives DNA damage produced by reactive species generated in its hosts. The activity of a T. cruzi FLAP endonuclease (TcFEN1) was determined in the three cellular forms of the parasite using a DNA substrate generated by annealing three different oligonucleotides to form a double-stranded DNA with a 5' flap in the middle. This activity showed optimal pH and temperature similar to other known FENs. The substrate cut by the flap endonuclease activity could be ligated by the parasite generating a repaired DNA product. A DNA flap endonuclease coding sequence found in the T. cruzi genome (TcFEN1) was cloned, inserted in parasite expression vectors and transfected to epimastigotes. The purified native recombinant protein showed DNA flap endonuclease activity. This endonuclease was found located in the parasite nucleus of transfected epimastigotes and its over-expression increased both parasite proliferation and survival to H 2 O 2 . The presence of a flap endonuclease activity in T. cruzi and its nuclear location are indicative of the participation of this enzyme in DNA processing of flap fragments during DNA replication and repair in this parasite of ancient evolutive origin. J. Cell. Biochem. 118: 1722-1732, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  14. Active control of ionized boundary layers

    CERN Document Server

    Mendes, R V

    1997-01-01

    The challenging problems, in the field of control of chaos or of transition to chaos, lie in the domain of infinite-dimensional systems. Access to all variables being impossible in this case and the controlling action being limited to a few collective variables, it will not in general be possible to drive the whole system to the desired behaviour. A paradigmatic problem of this type is the control of the transition to turbulence in the boundary layer of fluid motion. By analysing a boundary layer flow for an ionized fluid near an airfoil, one concludes that active control of the transition amounts to the resolution of an generalized integro-differential eigenvalue problem. To cope with the required response times and phase accuracy, electromagnetic control, whenever possible, seems more appropriate than mechanical control by microactuators.

  15. Anterolateral thigh myocutaneous flaps as the preferred flaps for reconstruction of oral and maxillofacial defects.

    Science.gov (United States)

    Ren, Zhen-Hu; Wu, Han-Jiang; Wang, Kai; Zhang, Sheng; Tan, Hong Yu; Gong, Zhao Jian

    2014-12-01

    The anterolateral thigh myocutaneous flap is one of the most commonly used flaps in reconstructive procedures, but its application in oral and maxillofacial defects has not been fully determined. Herein, we summarize the application of 1212 anterolateral thigh myocutaneous flaps in the repair of oral and maxillofacial defects and examine their benefits in maxillofacial reconstruction of these defects. Patients were recruited from February 2002 to June 2013 in the Department of Oral and Maxillofacial Surgery of Central South University. All patients underwent reconstructive surgery employing anterolateral thigh myocutaneous flaps. Patient ages ranged from 6 to 82 years with a mean age of 51.2 years. There are 1015 flaps showing single lobe and 197 flaps showing a multi-island pedicle and one of which carries the iliac bone. The largest area among the single flaps was 28 × 12 cm(2), and the smallest was 3 × 2 cm(2). Among the 1212 transferred flaps, 1176 survived and 36 showed necrosis, a survival rate of about 97.0%. The common complications at flap donor site were poor wound healing (10.1%), localized paraesthesia (50.1%), and altered quadriceps force (11.0%). No cases presented with local serious complications, and 90% of patients achieved good functional recovery and aesthetically acceptable results after reconstruction of oral and maxillofacial defects at various locations using anterolateral thigh myocutaneous flaps. The time (23-121 min; average 51 min) for anastomosis of one vein and one artery was significantly less than that for two veins and one artery (45-153 min, average 83 min; p = 0.0003), which indicates one vein anastomosis can significantly reduce the operating time. The anterolateral thigh myocutaneous flaps can be easily obtained and can provide a good amount of muscle for filling dead space and fascia lata. These flaps can be prepared into a separate fat flap, multi-island fascia with iliac bone, and other composite pedicle flaps to meet the

  16. [Digital artery bilobed flap for the treatment of skin degloving injury of thumb].

    Science.gov (United States)

    Zhang, Yang; Xin, Chang-Tai

    2014-04-01

    To explore clinical effects of digital artery bilobed flap for the treatment of skin degloving injury of thumb. From January 2007 to December 2012, 45 patients with skin degloving injury of thumb were treated with grafting of digital artery bilobed flap. There were 39 males and 6 females, ranging in age from 19 to 46 years, with an average of 32 years. The disease course ranged from 0.5 to 15 h. Eighteen patients suffered from defect of palmar skin above nail root and nail bed, 19 patients suffered from skin degloving injury of thumb phalangette, and 8 patients had whole skin degloving injury of thumb. The double lobe flaps were designed at the ulnar side of middle finger and the radial side of ring finger according to the defect of thumb skin. The arteria digitalis communis between the middle and ring fingers and its two branches of arteriae digitales propriae supplying the two fingers were used as a vessel pedicle. The flap with digitales proprii nervi was transposed and used to cover the exposed phalanx of thumb. Full thickness graft was used for the donor site. Observation of the appearance, texture, color and wear resistance of flap, appearance, color and depression of grafting area, skin feeling, and finger activities was conducted. All the flaps and grafts were alive. Forty-three patients were followed up with an average duration of 25 months, and two patients lost follow-up. The color and texture of the flaps were similar to that of the contralateral thumb pulp. The average two point discrimination was 4.2 +/- 0.3 mm. The color of graft skin was slightly deeper than that of the surroundings skin. Digital artery bilobed flap graft is an effective and ideal operation, which is of low risk and high success rates for skin degloving injury of thumb.

  17. Compartmentalization of immune responses during Staphylococcus aureus cranial bone flap infection.

    Science.gov (United States)

    Cheatle, Joseph; Aldrich, Amy; Thorell, William E; Boska, Michael D; Kielian, Tammy

    2013-08-01

    Decompressive craniectomy is often required after head trauma, stroke, or cranial bleeding to control subsequent brain swelling and prevent death. The infection rate after cranial bone flap replacement ranges from 0.8% to 15%, with an alarming frequency caused by methicillin-resistant Staphylococcus aureus, which is problematic because of recalcitrance to antibiotic therapy. Herein we report the establishment of a novel mouse model of S. aureus cranial bone flap infection that mimics several aspects of human disease. Bacteria colonized bone flaps for up to 4 months after infection, as revealed by scanning electron microscopy and quantitative culture, demonstrating the chronicity of the model. Analysis of a human cranial bone flap with confirmed S. aureus infection by scanning electron microscopy revealed similar structural attributes as the mouse model, demonstrating that it closely parallels structural facets of human disease. Inflammatory indices were most pronounced within the subcutaneous galeal compartment compared with the underlying brain parenchyma. Specifically, neutrophil influx and chemokine expression (CXCL2 and CCL5) were markedly elevated in the galea, which demonstrated substantial edema on magnetic resonance images, whereas the underlying brain parenchyma exhibited minimal involvement. Evaluation of immune mechanisms required for bacterial containment and inflammation revealed critical roles for MyD88-dependent signaling and neutrophils. This novel mouse model of cranial bone flap infection can be used to identify key immunologic and therapeutic mechanisms relevant to persistent bone flap infection in humans. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  18. Jacket Substructure Fatigue Mitigation through Active Control

    DEFF Research Database (Denmark)

    Hanis, Tomas; Natarajan, Anand

    2014-01-01

    to the fatigue design loads on the braces of the jacket. Since large wind turbines of 10MW rating have low rotor speeds (p), the modal frequencies of the sub structures approach 3p at low wind speeds, which leads to a modal coupling and resonance. Therefore an active control system is developed which provides...... sufficient structural damping and consequently a fatigue reduction at the substructure. The resulting reduction in fatigue design loads on the jacket structure based on the active control system is presented....

  19. The DelFly design, aerodynamics, and artificial intelligence of a flapping wing robot

    CERN Document Server

    de Croon, G C H E; Remes, B D W; Ruijsink, R; De Wagter, C

    2016-01-01

    This book introduces the topics most relevant to autonomously flying flapping wing robots: flapping-wing design, aerodynamics, and artificial intelligence. Readers can explore these topics in the context of the "Delfly", a flapping wing robot designed at Delft University in The Netherlands. How are tiny fruit flies able to lift their weight, avoid obstacles and predators, and find food or shelter? The first step in emulating this is the creation of a micro flapping wing robot that flies by itself. The challenges are considerable: the design and aerodynamics of flapping wings are still active areas of scientific research, whilst artificial intelligence is subject to extreme limitations deriving from the few sensors and minimal processing onboard. This book conveys the essential insights that lie behind success such as the DelFly Micro and the DelFly Explorer. The DelFly Micro, with its 3.07 grams and 10 cm wing span, is still the smallest flapping wing MAV in the world carrying a camera, whilst the DelFly Expl...

  20. Comparison of soft tissue healing around implants in beagle dogs: flap surgery versus flapless surgery.

    Science.gov (United States)

    Lei, Qun; Chen, Jiang; Jiang, Jianhui; Fu, Xiaoming; Lin, Hengzhang; Cai, Zhiyu

    2013-03-01

    The objective of this study was to compare soft tissue healing after implant placement in flap and flapless surgery in the dog model. Mandibular premolars were extracted from 10 beagle dogs. The extraction sockets were allowed to heal for 8 weeks. After healing, 3 implants on each side of the mandible were implanted using either flap or flapless techniques. One implant was installed on each side at the 0-, 4-, and 6-week time point. Eight weeks later, the peri-implant soft tissue healing was subjected to clinical and immunohistochemical analysis. It was revealed that vascular endothelial growth factor (VEGF) expression, peri-implant crevicular fluid (PICF) volume, and the aspartate aminotransferase and alkaline phosphatase activity in PICF increased significantly in the 2-week flap group compared with the 2-week flapless group. Microvascular density and VEGF expression in the 8-week flap group was statistically significantly lower than the 8-week flapless group and normal group. Buccal gingival recession was less pronounced in the flapless group than in the flap group after 4 and 8 weeks. Within the limits of this study, the results demonstrate that flapless surgery contributes to better esthetic outcomes in implants compared with the flap approach. Crown Copyright © 2013. Published by Mosby, Inc. All rights reserved.

  1. JCMT active surface control system: implementation

    Science.gov (United States)

    Smith, Ian A.

    1998-05-01

    The James Clerk Maxwell Telescope on the summit of Mauna Kea in Hawaii is a 15 meter sub-millimeter telescope which operates in the 350 microns to 2 millimeter region. The primary antenna surface consists of 276 panels, each of which is positioned by 3 stepper motors. In order to achieve the highest possible surface accuracy we are embarking upon a project to actively control the position of the panels adjuster system is based on a 6809 micro connected to the control computer by a GPIB interface. This system is slow and inflexible and it would prove difficult to build an active surface control system with it. Part of the upgrade project is to replace the existing micro with a 68060 VME micro. The poster paper will describe how the temperature of the antenna is monitored with the new system, how a Finite Element Analyses package transforms temperature changes into a series of panel adjuster moves, and how these moves are then applied to the surface. The FEA package will run on a high end Sun workstation. A series of DRAMA tasks distributed between the workstation and the Baja 68060 VxWorks Active Surface Control System micro will control the temperature monitoring, FEA and panel adjustment activities. Users can interact with the system via a Tcl/TK based GUI.

  2. Designing Trailing Edge Flaps of Wind Turbines using an Integrated Design Approach

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

    In this paper designing a controller for trailing edge flaps (TEF) as well as optimizing its position on the wind turbine blade will be considered. An integrated design approach will be used to optimize both TEF placement and controller simultaneously. Youla parameterization will be used to param......In this paper designing a controller for trailing edge flaps (TEF) as well as optimizing its position on the wind turbine blade will be considered. An integrated design approach will be used to optimize both TEF placement and controller simultaneously. Youla parameterization will be used...

  3. Tobacco Control and Health Promotion Activities

    OpenAIRE

    Spasovski, Mome; Donev, Doncho; Arnikov, Aleksandar; Karadzinski, Jaroslav

    2008-01-01

    The use of tobacco is considered as one of the main risk factors for numerous chronic diseases, such as: lung diseases, cancer, and cardiovascular diseases. 4.9 million deaths per year worldwide are tobacco related, having an increasing trend that will lead to double death toll by 2020. WHO is one of the leading organizations in the world actively involved in the health promotion activities related to tobacco consumption reduction and tobacco control. In this regard WHO prepared the Framework...

  4. Active disturbance rejection controller for chemical reactor

    Energy Technology Data Exchange (ETDEWEB)

    Both, Roxana; Dulf, Eva H.; Muresan, Cristina I., E-mail: roxana.both@aut.utcluj.ro [Technical University of Cluj-Napoca, 400114 Cluj-Napoca (Romania)

    2015-03-10

    In the petrochemical industry, the synthesis of 2 ethyl-hexanol-oxo-alcohols (plasticizers alcohol) is of high importance, being achieved through hydrogenation of 2 ethyl-hexenal inside catalytic trickle bed three-phase reactors. For this type of processes the use of advanced control strategies is suitable due to their nonlinear behavior and extreme sensitivity to load changes and other disturbances. Due to the complexity of the mathematical model an approach was to use a simple linear model of the process in combination with an advanced control algorithm which takes into account the model uncertainties, the disturbances and command signal limitations like robust control. However the resulting controller is complex, involving cost effective hardware. This paper proposes a simple integer-order control scheme using a linear model of the process, based on active disturbance rejection method. By treating the model dynamics as a common disturbance and actively rejecting it, active disturbance rejection control (ADRC) can achieve the desired response. Simulation results are provided to demonstrate the effectiveness of the proposed method.

  5. The plane problem of the flapping wing

    Science.gov (United States)

    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.

  6. Flap Gap Oscillatory Blowing on 2D and 2.5D Wing

    Directory of Open Access Journals (Sweden)

    Cătălin NAE

    2009-12-01

    Full Text Available Here we present preliminary results obtained in developing an active flow control system for highlift systems at advanced TRL level. The work is based on theoretical and experimental workperformed in AVERT EU FP6 project where the oscillatory flap gap blowing system was designedand tested on a INCAS F15 2D wing model. Pressure data and global loads have been recorded fora complex evaluation of the basic flow control mechanism. In 2.5D test cases this work has beenextended so that the proposed system may be selected as a mature technology in the JTI Clean Sky,Smart Fixed Wing Aircraft ITD. For this goal, new experimental setup was used and also updatedelectronics for the blowing system have been introduces. This was complemented by a newextension for the data acquisition system and visualization tools. Finally global correlations forbasic lift increments have been compared with the reference 2D case and analysed with respect tothe system efficiency.

  7. Topical application of nitrosonifedipine, a novel radical scavenger, ameliorates ischemic skin flap necrosis in a mouse model.

    Science.gov (United States)

    Fukunaga, Yutaka; Izawa-Ishizawa, Yuki; Horinouchi, Yuya; Sairyo, Eriko; Ikeda, Yasumasa; Ishizawa, Keisuke; Tsuchiya, Koichiro; Abe, Yoshiro; Hashimoto, Ichiro; Tamaki, Toshiaki

    2017-04-01

    Ischemic skin flap necrosis can occur in random pattern flaps. An excess amount of reactive oxygen species is generated and causes necrosis in the ischemic tissue. Nitrosonifedipine (NO-NIF) has been demonstrated to possess potent radical scavenging ability. However, there has been no study on the effects of NO-NIF on ischemic skin flap necrosis. Therefore, they evaluated the potential of NO-NIF in ameliorating ischemic skin flap necrosis in a mouse model. A random pattern skin flap (1.0 × 3.0 cm) was elevated on the dorsum of C57BL/6 mice. NO-NIF was administered by topical injection immediately after surgery and every 24 hours thereafter. Flap survival was evaluated on postoperative day 7. Tissue samples from the skin flaps were harvested on postoperative days 1 and 3 to analyze oxidative stress, apoptosis and endothelial dysfunction. The viable area of the flap in the NO-NIF group was significantly increased (78.30 ± 7.041%) compared with that of the control group (47.77 ± 6.549%, p NIF reduced oxidative stress, apoptosis and endothelial dysfunction, which were evidenced by the decrease of malondialdehyde, p22phox protein expression, number of apoptotic cells, phosphorylated p38 MAPK protein expression, and vascular cell adhesion molecule-1 protein expression while endothelial nitric oxide synthase protein expression was increased. In conclusion, they demonstrated that NO-NIF ameliorated ischemic skin flap necrosis by reducing oxidative stress, apoptosis, and endothelial dysfunction. NO-NIF is considered to be a candidate for the treatment of ischemic flap necrosis. © 2017 by the Wound Healing Society.

  8. Control of Liquid Sloshing Container using Active Force Control Method

    Science.gov (United States)

    Setyo Purnomo, Didik; Rachmad Anom Besari, Adnan; Darojah, Zaqiatud

    2017-04-01

    This paper presents a robust control method to relieve the sloshing of liquid container transport using Active Force Control (AFC) method. A model of two degree-of-freedom (2-DOF) liquid container transfer was implemented in this research as the main dynamical system to be controlled. The surface of liquid is maintained in a flat position, so that changes the slope of liquid surface countered by changing the acceleration of container. The focus of this research is how to use AFC method being applied to the system, so that it can suppress liquid sloshing. The control scheme were simulated, compare between PID-AFC and pure PID. Simulations has been conducted, the results show that the PID-AFC have superior performance to suppress the sloshing compared with pure PID, especially if disturbance occurred.

  9. On the Use of Active Higher Harmonic Blade Pitch Control for Helicopter Vibration Reduction,

    Science.gov (United States)

    1980-06-01

    superimposing non-rotating swashplate motions at the blade passage frequency (4P for a 4 bladed rotor) upon the basic collective and cyclic flight...is changed using a remotely controlled hydraulic actuator and electric servo system. The rotor control system is a conventional swashplate system...measured by linear potentiometers connected to the swashplate . Rotor blade flapping and lagging are measured by rotary potentiometers mounted on the

  10. Limited Investigation of Active Feel Control Stick System (Active Stick)

    Science.gov (United States)

    2009-06-01

    the event the safety pilot became incapacitated or certain control cable failures occurred, the evaluation pilot was able to fly the aircraft as a... Kingfisher Dr Charlotte, NC 28226 Paper/PDF 1 Total Copies 21 June 2009 Active Stick G-2

  11. Neural predictive control for active buffet alleviation

    Science.gov (United States)

    Pado, Lawrence E.; Lichtenwalner, Peter F.; Liguore, Salvatore L.; Drouin, Donald

    1998-06-01

    The adaptive neural control of aeroelastic response (ANCAR) and the affordable loads and dynamics independent research and development (IRAD) programs at the Boeing Company jointly examined using neural network based active control technology for alleviating undesirable vibration and aeroelastic response in a scale model aircraft vertical tail. The potential benefits of adaptive control includes reducing aeroelastic response associated with buffet and atmospheric turbulence, increasing flutter margins, and reducing response associated with nonlinear phenomenon like limit cycle oscillations. By reducing vibration levels and thus loads, aircraft structures can have lower acquisition cost, reduced maintenance, and extended lifetimes. Wind tunnel tests were undertaken on a rigid 15% scale aircraft in Boeing's mini-speed wind tunnel, which is used for testing at very low air speeds up to 80 mph. The model included a dynamically scaled flexible fail consisting of an aluminum spar with balsa wood cross sections with a hydraulically powered rudder. Neural predictive control was used to actuate the vertical tail rudder in response to strain gauge feedback to alleviate buffeting effects. First mode RMS strain reduction of 50% was achieved. The neural predictive control system was developed and implemented by the Boeing Company to provide an intelligent, adaptive control architecture for smart structures applications with automated synthesis, self-optimization, real-time adaptation, nonlinear control, and fault tolerance capabilities. It is designed to solve complex control problems though a process of automated synthesis, eliminating costly control design and surpassing it in many instances by accounting for real world non-linearities.

  12. Patient morbidity and root coverage outcomes after the application of a subepithelial connective tissue graft in combination with a coronally advanced flap or via a tunneling technique: a randomized controlled clinical trial.

    Science.gov (United States)

    Gobbato, Luca; Nart, Jose; Bressan, Eriberto; Mazzocco, Fabio; Paniz, Gianluca; Lops, Diego

    2016-11-01

    Subepithelial connective tissue grafts (SeCTG) in conjunction with a coronally advanced flap (CAF) or with tunneling technique (TT) are common periodontal procedures with similar indications for the treatment of a denuded root surface; however, it is unclear whether patient discomfort and postoperative morbidity are comparable in both approaches. The aim of this randomized controlled clinical trial was to compare the patient morbidity and root coverage outcomes of a SeCTG used in combination with a CAF or TT. For this single-center, randomized, clinical trial, patients were randomly assigned to receive SeCTG + CAF (control group) or SeCTG + TT (test group). Postoperative questionnaires at 3 days post intervention were administered to evaluate postoperative discomfort, bleeding, and inability to masticate. Evaluation of patients' perception of pain was performed using a visual analog scale (VAS). Clinical outcomes including percentage of root coverage (RC) and complete root coverage (CRC) were recorded 12 months postoperatively. Fifty patients (25 SeCTG + CAF and 25 SeCTG + TT) completed the study. Healing was uneventful for all test and control patients. The SeCTG + TT group showed a longer chair time (33.6 (3.6) and 23.6 (4.2) min for the SeCTG + TT and the SeCTG + CAF, respectively), as well as more painkiller consumption: 2736 vs. 1536 mg (p < 0.001). At the same time, the SeCTG + CAF group reported less pain or discomfort in all four sections of the questionnaire: pain experienced within the mouth as a whole, pain experienced throughout the day, pain experienced at night, and edema experienced after the surgery (p = 0.002, p = 0.001, p = 0.001, and p = 0001, respectively). Both treatments showed clinical efficacy in terms of root coverage as no differences per group were observed in the percentage of root coverage (87 vs. 85 %, p = 704) or patients with complete root coverage (60 vs. 52 %, p = 0.569). SeCTG + TT is

  13. Active controls technology to maximize structural efficiency

    Science.gov (United States)

    Hoy, J. M.; Arnold, J. M.

    1978-01-01

    The implication of the dependence on active controls technology during the design phase of transport structures is considered. Critical loading conditions are discussed along with probable ways of alleviating these loads. Why fatigue requirements may be critical and can only be partially alleviated is explained. The significance of certain flutter suppression system criteria is examined.

  14. Helium-neon laser in viability of random skin flap in rats.

    Science.gov (United States)

    Pinfildi, Carlos E; Liebano, Richard E; Hochman, Bernardo S; Ferreira, Lydia M

    2005-07-01

    The purpose of this study was to determine the role of helium-neon (He-Ne) laser random skin flap viability in rats. Experimentally controlled randomized study. Forty-eight Wistar-EPM rats were used, weighed, and divided into 4 groups with 12 rats each. The random skin flap was performed measuring 10 x 4 cm, with a plastic sheet interposed between the flap and the donor site. The Group 1 (control) underwent sham irradiation with He-Ne laser. The Group 2 was submitted to laser irradiation, using the punctual contact technique on the skin flap surface. The Group 3 was submitted to laser irradiation surrounding the skin flap, and the Group 4 was submitted to laser irradiation both on the skin flap surface and around it. The experimental groups were submitted to He-Ne laser irradiation with 3 J/cm(2) energy density immediately after the surgery and for the four subsequent days. The percentage of necrotic area of the four groups was calculated at the 7th post-operative day, through a paper-template method. Group 1 reached an average necrotic area of 48.86%; Group 2, 38.67%; Group 3, 35.34%; and Group 4, 22.61%. After the statistic analysis, results showed that all experimental groups reached statistically significant values when compared to the control group, and Group 4 was the best one, when compared to all groups of this study (P<0.001). The He-Ne laser irradiation was efficient to increase random skin flap viability in rats. (c) 2005 Wiley-Liss, Inc.

  15. Growth control: brassinosteroid activity gets context.

    Science.gov (United States)

    Singh, Amar Pal; Savaldi-Goldstein, Sigal

    2015-02-01

    Brassinosteroid activity controls plant growth and development, often in a seemingly opposing or complex manner. Differential impact of the hormone and its signalling components, acting both as promoters and inhibitors of organ growth, is exemplified by meristem differentiation and cell expansion in above- and below-ground organs. Complex brassinosteroid-based control of stomata count and lateral root development has also been demonstrated. Here, mechanisms underlying these phenotypic outputs are examined. Among these, studies uncovering core brassinosteroid signalling components, which integrate with distinct peptide, hormone, and environmental pathways, are reviewed. Finally, the differential spatiotemporal context of brassinosteroid activity within the organ, as an important determinant of controlled growth, is discussed. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. Wind Turbine Rotors with Active Vibration Control

    DEFF Research Database (Denmark)

    Svendsen, Martin Nymann

    This thesis presents a framework for structural modeling, analysis and active vibration damping of rotating wind turbine blades and rotors. A structural rotor model is developed in terms of finite beam elements in a rotating frame of reference. The element comprises a representation of general...... formulation. The element provides an accurate representation of the eigenfrequencies and whirling modes of the gyroscopic system, and identifies lightly damped edge-wise modes. By adoption of a method for active, collocated resonant vibration of multi-degree-of-freedom systems it is demonstrated...... that these are geometrically well separated. For active vibration control in three-bladed wind turbine rotors the present work presents a resonance-based method for groups of one collective and two whirling modes. The controller is based on the existing resonant format and introduces a dual system targeting the collective...

  17. Active control of transmitted sound in buildings

    Science.gov (United States)

    Thompsett, Russell Harvey George

    The problem of noise from neighbours has increased dramatically over the last few years. Many of the noise complaints are due to the high level, low frequency noise from modern stereo equipment, and are often described in terms of the low frequency characteristics of the music; the repetitive, booming, bass beat. The objective of this research was to establish the feasibility of applying active noise control to alleviate this problem. The initial approach was to evaluate the possibility of exploiting the dominance of individual modes in the response of rooms at low frequency to effect global control. However, initial investigations using a modal model of the sound field revealed that this would be difficult due to the contribution of many acoustic modes excited off resonance. This conclusion was supported by measurements of acoustic room responses in typical buildings, illustrating a non-resonant characteristic. Consequently, attention was turned to the feasibility of using local active control systems to create zones of quiet by concentrating control at a specific location near the observers ears, for example in a seat headrest, or near the pillows of a bed. The lack of a reference signal in either approach requires the use of a feedback control strategy. With a typically non-resonant system, the predictability in the disturbance necessary for successful feedback control must be contained in the primary excitation, namely the music. Examples of different music styles were investigated and of those with the potential to be a nuisance surprisingly few were significantly more predictable than a random disturbance. As expected the most encouraging control performance simulations were found for modern dance music, with a strong repetitive beat. A real-time, local controller was demonstrated in the laboratory with such a disturbance signal and the properties of the quiet zone were measured. The subjective response when hearing the controller in operation was found to be

  18. Improving Accuracy of Processing Through Active Control

    Directory of Open Access Journals (Sweden)

    N. N. Barbashov

    2016-01-01

    Full Text Available An important task of modern mathematical statistics with its methods based on the theory of probability is a scientific estimate of measurement results. There are certain costs under control, and under ineffective control when a customer has got defective products these costs are significantly higher because of parts recall.When machining the parts, under the influence of errors a range scatter of part dimensions is offset towards the tolerance limit. To improve a processing accuracy and avoid defective products involves reducing components of error in machining, i.e. to improve the accuracy of machine and tool, tool life, rigidity of the system, accuracy of the adjustment. In a given time it is also necessary to adapt machine.To improve an accuracy and a machining rate there, currently  become extensively popular various the in-process gaging devices and controlled machining that uses adaptive control systems for the process monitoring. Improving the accuracy in this case is compensation of a majority of technological errors. The in-cycle measuring sensors (sensors of active control allow processing accuracy improvement by one or two quality and provide a capability for simultaneous operation of several machines.Efficient use of in-cycle measuring sensors requires development of methods to control the accuracy through providing the appropriate adjustments. Methods based on the moving average, appear to be the most promising for accuracy control since they include data on the change in some last measured values of the parameter under control.

  19. [Flap endonuclease-1 and its role in the processes of DNA metabolism in eucaryotic cells].

    Science.gov (United States)

    Nazarkina, Zh K; Lavrik, O I; Khodyreva, S N

    2008-01-01

    Flap endonuclease-1 (FEN1) is a structure specific endonuclease. The natural substrates of FEN1 are 5'-flap structures formed by three DNA chains one of them has unannealed flapped 5'-end (flap). Flap structures are the intermediates of different processes of DNA metabolism, such as DNA recombination, Okazaki fragment maturation during replication of lagging strand, as well as strand displacement DNA synthesis in base excision repair. FEN1 also possesses 5'-exonuclease activity and newly discovered gap endonuclease activity. FEN1 is known to interact physically and functionally with a number of DNA replication and repair proteins such as the proliferating cell nuclear antigen, helicase/nuclease Dna2, WRN and BLM proteins, replication protein A, apurinic/apyrimidinic endonuclease 1, DNA polymerase beta, poly(ADP-riboso) polymerase 1, high mobility group protein 1, integrase of human immunodeficiency virus, transcription coactivator p300, chromatin proteins, cyclin-dependent kinases (Cdk1, Cdk2, Cyclin A). FEN1 activity is significant for maintaining the integrity of repeat sequences in genome. Recent data suppose the correlation between the abnormality of hFEN1 activity and arising/progression of neurodegenerative and cancer diseases. FEN1 has the dramatic effect on cell growth and development thereby attracting the interest to this enzyme.

  20. Postirradiation flap infection about the oral cavity

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Periodic and Chaotic Flapping of Insectile Wings

    CERN Document Server

    Huang, Yangyang

    2015-01-01

    Insects use flight muscles attached at the base of the wings to produce impressive wing flapping frequencies. The maximum power output of these flight muscles is insufficient to maintain such wing oscillations unless there is good elastic storage of energy in the insect flight system. Here, we explore the intrinsic self-oscillatory behavior of an insectile wing model, consisting of two rigid wings connected at their base by an elastic torsional spring. We study the wings behavior as a function of the total energy and spring stiffness. Three types of behavior are identified: end-over-end rotation, chaotic motion, and periodic flapping. Interestingly, the region of periodic flapping decreases as energy increases but is favored as stiffness increases. These findings are consistent with the fact that insect wings and flight muscles are stiff. They further imply that, by adjusting their muscle stiffness to the desired energy level, insects can maintain periodic flapping mechanically for a range of operating condit...

  2. A novel algorithm for OSPF link flap damping

    Science.gov (United States)

    Yang, Yang; Liu, Guangyi; Lin, Xiaokang

    2005-02-01

    Open shortest path first (OSPF) is the most widely used routing protocol in today"s IP networks, and its excellent performance has been proved in wired environments. However, when it is executed under bad channel conditions such as in wireless networks or areas with severe signal interference, links may flap frequently and some terrible problems will appear. This paper proposes a novel algorithm called OSPF link flap damping algorithm (OLFDA). The objective of OLFDA is to reduce the events of link state advertisement (LSA) update and damp the link flap with the precondition that the overall network performance is satisfying. To accomplish this, we can define criteria to identify and dynamically suppress the poorly behaved links. Information of the suppressed links won"t be advertised in OSPF domain and used in calculation of the routing tables. In addition, we can control the maximal number of links suppressed simultaneously by a router to ensure the network connectivity. OLFDA are simulated in many scenarios, and the results indicate that the algorithm has an excellent performance.

  3. Modeling the Motion of a Flapping Wing Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Vorochaeva L.Y.

    2017-01-01

    Full Text Available The article discusses the vertical flight of a flapping wing aerial vehicle, which is also called an ornithopter. The robot is a chain of five links connected in series by active cylindrical hinges with the central link being the body and the remainder forming folding wings in pairs. The distinctive feature of this device is that the flaps of its wings imitate those of a seagull i.e. the device has a biological prototype. We construct a mathematical model of this device; much attention is given to the model of the interaction of the wings with the air environment and we determine the positions and velocities of points of application of the reduced aerodynamic forces to each of the links. Based on the results of numerical modelling of the vertical flight of the robot three modes of flight were established: ascent, hovering at a certain height and descent. The device can operate in these modes based on the oscillation parameters of the wings in particular flapping frequency and amplitude, the ratio of the amplitudes of two links and one wing and the shift of the equilibrium oscillation position of the wings relative to zero.

  4. Actively controlled vibration welding system and method

    Science.gov (United States)

    Cai, Wayne W.; Kang, Bongsu; Tan, Chin-An

    2013-04-02

    A vibration welding system includes a controller, welding horn, an active material element, and anvil assembly. The assembly may include an anvil body connected to a back plate and support member. The element, e.g., a piezoelectric stack or shape memory alloy, is positioned with respect to the assembly. The horn vibrates in a desirable first direction to form a weld on a work piece. The element controls any vibrations in a second direction by applying calibrated response to the anvil body in the second direction. A method for controlling undesirable vibrations in the system includes positioning the element with respect to the anvil assembly, connecting the anvil body to the support member through the back plate, vibrating the horn in a desirable first direction, and transmitting an input signal to the element to control vibration in an undesirable second direction.

  5. Control Systems Cyber Security Standards Support Activities

    Energy Technology Data Exchange (ETDEWEB)

    Robert Evans

    2009-01-01

    The Department of Homeland Security’s Control Systems Security Program (CSSP) is working with industry to secure critical infrastructure sectors from cyber intrusions that could compromise control systems. This document describes CSSP’s current activities with industry organizations in developing cyber security standards for control systems. In addition, it summarizes the standards work being conducted by organizations within the sector and provides a brief listing of sector meetings and conferences that might be of interest for each sector. Control systems cyber security standards are part of a rapidly changing environment. The participation of CSSP in the development effort for these standards has provided consistency in the technical content of the standards while ensuring that information developed by CSSP is included.

  6. Flapping flight aerodynamics for flying animals

    OpenAIRE

    Norizham, Abdul Razak; Dimitriadis, Grigorios

    2011-01-01

    Most research into the aerodynamics of flying animals is based on aircraft aerodynamics. Aircraft have rigid wings, therefore such research is mostly suited to the study of the gliding flight of animals. However, many species spend more time flapping than gliding. Some species don’t glide at all. This seminar presents recent work on flapping flight carried out at the University of Liège.

  7. Active vibration control using DEAP actuators

    Science.gov (United States)

    Sarban, Rahimullah; Jones, Richard W.

    2010-04-01

    Dielectric electro-active polymer (DEAP) is a new type of smart material, which has the potential to be used to provide effective actuation for a wide range of applications. The properties of DEAP material place it somewhere between those of piezoceramics and shape memory alloys. Of the range of DEAP-based actuators that have been developed those having a cylindrical configuration are among the most promising. This contribution introduces the use of a tubular type DEAP actuator for active vibration control purposes. Initially the DEAP-based tubular actuator to be used in this study, produced by Danfoss PolyPower A/S, is introduced along with the static and dynamic characteristics. Secondly an electromechanical model of the tubular actuator is briefly reviewed and its ability to model the actuator's hysteresis characteristics for a range of periodic input signals at different frequencies demonstrated. The model will be used to provide hysteresis compensation in future vibration isolation studies. Experimental active vibration control using the actuator is then examined, specifically active vibration isolation of a 250 g mass subject to shaker generated 'ground vibration'. An adaptive feedforward control strategy is used to achieve this. The ability of the tubular actuator to reject both tonal and broadband random vibratory disturbances is then demonstrated.

  8. New perspective on the in vivo use of cold stress dynamic thermography in integumental reconstruction with the use of skin-muscle flaps.

    Science.gov (United States)

    Kolacz, Szymon; Moderhak, Mateusz; Jankau, Jerzy

    2017-05-15

    Among the problems encountered by plastic surgeons is the reconstruction of defects following tumors. One of the reconstructive options is trans rectus abdominis (TRAM) flap. Despite that anatomy is well explored, marginal flap necrosis may develop. To minimize the complications, imaging examinations were designed to determine the degree of flap perfusion. One of them is the thermographic examination. We examined 38 patients who had undergone 10 reconstructive breast surgeries with a pedicled TRAM ipsilateral flap, 10 patients with a TRAM contralateral flap, and 18 patients with a TRAM supercharged flap. Each operated patient underwent a thermographic examination before the surgery, after the dissection of the skin-muscle flap, immediately after suturing flap, and during the first and seventh day after the surgery. The collected data were then processed to yield results in a numerical form and compared with clinical examination. The aim of this study is to evaluate the efficacy of new thermal model calculation of dTnorm and t90_10 in cold stress dynamic thermography in the in vivo assessment of intraoperative and postoperative skin blood supply in humans before ischemic lesions become clinically apparent. Of 38 patients participating in the study, nine patients developed marginal necrosis of the skin flap despite intraoperative clinical evaluation of blood supply. Explicit circulatory disorders apparent in a clinical examination developed after 24 h. Cold stress tnorm and t90_10 dynamic thermography can be a helpful additional tool to assess and monitor the blood supply to the flap skin both intraoperatively and postoperatively. Active dynamic thermography; cold stress dynamic thermography, thermography; TRAM; flap necrosis; flap monitoring, breast reconstruction. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Mastoid fascia kite flap for cryptotia correction.

    Science.gov (United States)

    Simon, François; Celerier, Charlotte; Garabedian, Erea-Noël; Denoyelle, Françoise

    2016-11-01

    Cryptotia is one of the most common malformations of the upper auricle with aesthetic and functional consequences, however there is no standard treatment. We present the surgical technique and results of a kite flap procedure which can be used in the different cryptotia subtypes. We reviewed all patients treated in our department from 2010 to 2015, using a mastoid fascia kite flap technique. The incision of this local flap follows the retro-auricular sulcus along the rim of the helix superiorly and drawing a skin paddle inferiorly. The mastoid fascia is exposed and a superiorly and posteriorly based flap is drawn and detached from the skull. Finally, the skin paddle is rotated and sutured between the superior helix and temporal skin creating the superior sulcus. The retro-auricular incision is closed directly inferiorly. Six patients (mean age 12) and seven ears were studied. One patient had bilateral cryptotia and only two had a normal contralateral ear. Mean follow-up was of 45 months. There was no skin necrosis, no complications reported and no revision surgery. We describe a reliable flap with a simple design and improved aesthetic result, as the thickness of the flap projects the helix well, the scar is entirely hidden in the retro-auricular sulcus and the direct suture induces a harmonious medialization of the inferior part of the ear and earlobe. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Combination of ischemic preconditioning and postconditioning can minimise skin flap loss: experimental study.

    Science.gov (United States)

    Akcal, Arzu; Sirvan, Selami Serhat; Karsidag, Semra; Görgülü, Tahsin; Akcal, Mehmet Akif; Ozagari, Aysim; Tatlidede, Soner

    2016-08-01

    Ischaemic preconditioning and postconditioning, which consist of one or a series of short ischaemic events. This study aimed to determine the efficiency of post-conditioning a flap in the minimisation of flap loss after a preconditioned skin flap. The rats were divided into five groups: sham group, control group, pre-con group, post-con group, and pre + post-con group. On postoperative days 3 and 7, the entire flaps along with the margins of necrosis were traced onto transparent sheets. The areas of intact skin and tissue were recorded. The flap necrosis area and percentage of necrosis were calculated for each animal. The necrotic area percentage of the control group was found to be significantly higher than those of the other groups on Days 3 and 7 (p = 0.01 and p = 0.03, respectively). The necrotic area percentage of the pre-con group was significantly higher than the pre + post-con group on Day 7 (p = 0.01). VEGFR-3 expression was observed at a rate of more than 50% in the post-con group. The presence of a protective effect in the late period was separately investigated by immunohistochemical staining of VEGFR-3 in the proliferating vessels. The necrotic areas was reduced in the flaps of the pre-con, post-con, and pre + post-con groups and the combined preconditioning and postconditioning group has reduced necrotic area compared to preconditioning of the skin flap. The protective effect was observed on day 7 for combined ischaemic preconditioning and postconditioning. The presence of a protective effect in the late period was separately investigated by immunohistochemical staining of VEGFR-3 in the proliferating vessels.

  11. The effect of recombinant hirudin on rabbit ear flaps with venous insufficiency

    Directory of Open Access Journals (Sweden)

    Serdar Duzgun

    2014-01-01

    Full Text Available The effect of recombinant hirudin, which is the most powerful antithrombotic agent, on flaps with venous insufficiency was investigated. Oedema and congestion are frequent on flaps, causing necrosis unpredictably. Venous insufficiency and thrombosis are experimentally and clinically more frequent than arterial occlusion. Twenty-one adult New Zealand rabbits were used in this study. Skin flaps (3 × 6 cm were elevated on a 1-cm-wide pedicle on rabbit ears. The artery, nerve, and vein were exposed and examined with the aid of a surgical microscope. Venous insufficiency was established by cutting the vein and nerve. In the control group, no additional surgical or medical procedures were performed and the ear flap was inset to its original location. Subcutaneous low molecular weight heparin (LMWH; 320 IU/kg was administered to a second group of rabbits after the same surgery, and recombinant hirudin (2 μg was administered via the pedicle artery 5 minutes after the vein and nerve were bound and cut in a third group of rabbits. Compared with control and LMWH groups on day 3 and 7, the hirudin-treated group had less hair loss, lower oedema scores and less haematoma formation. Furthermore, a lower size of necrotic areas and an increase in the circulating area on day 7 was found in the hirudin-treated group. In addition, angiography revealed new vessel development (neovascularisation only in the hirudin group. On histologic sections, hirudin-treated animals had lower oedema, inflammation and congestion scores than animals in the other two groups. Thus, when administered into the ear flap through the pedicle as a pure recombinant preparation, hirudin increased flap survival by its antithrombotic effects and by accelerating neoangiogenesis. Recombinant hirudin may be used in clinical practice to treat flaps with venous problems and to increase survival rates.

  12. A role of abdomen in butterfly's flapping flight

    Science.gov (United States)

    Jayakumar, Jeeva; Senda, Kei; Yokoyama, Naoto

    2017-11-01

    Butterfly's forward flight with periodic flapping motion is longitudinally unstable, and control of the thoracic pitching angle is essential to stabilize the flight. This study aims to comprehend roles which the abdominal motion play in the pitching stability of butterfly's flapping flight by using a two-dimensional model. The control of the thoracic pitching angle by the abdominal motion is an underactuated problem because of the limit on the abdominal angle. The control input of the thorax-abdomen joint torque is obtained by the hierarchical sliding mode control in this study. Numerical simulations reveal that the control by the abdominal motion provides short-term pitching stabilization in the butterfly's flight. Moreover, the control input due to a large thorax-abdomen joint torque can counteract a quite large perturbation, and can return the pitching attitude to the periodic trajectory with a short recovery time. These observations are consistent with biologists' view that living butterflies use their abdomens as rudders. On the other hand, the abdominal control mostly fails in long-term pitching stabilization, because it cannot directly alter the aerodynamic forces. The control for the long-term pitching stabilization will also be discussed.

  13. Effect of Frontal Gusts and Stroke Deviation in Forward Flapping Flight and Deconstructing the Aerodynamics of a Fruit Bat

    Science.gov (United States)

    Viswanath, Kamal

    dominated by the oscillatory motion. From the data the bat exhibits fine control of its mechanics by actively varying wing camber, wing area, torsional rotation of the wing, forward and backward translational sweep of the wing, and wing conformation to dictate the fluid dynamics. As is common in flapping flight, the primary force generation is through the attached unsteady vortices on the wing surface. This force output is modulated by the bat through varying wing camber and the wing area. Proper orthogonal decomposition of the wing kinematics is undertaken to compile a simpler set of kinematic modes that can approximate the original motion used by the fruit bat. These modes are then analyzed based on aerodynamic performance and power cost for more efficient flight. Understanding the physics of these modes will help us use them as prescribed kinematics for mechanical flappers as well as improve upon them from nature.

  14. The effect of polylactide membranes on the levels of reactive oxygen species in periodontal flaps during wound healing.

    Science.gov (United States)

    Aliyev, Eldar; Sakallioğlu, Umur; Eren, Zafer; Açikgöz, Gökhan

    2004-08-01

    It is consented that reactive oxygen species (ROS) are deleterious to wound healing process due to the harmful effects on cells and tissues. Absorbable synthetic biomaterials are considered to be degraded via ROS. Free-radical-scavenging enzymes (FRSE) are a cytoprotective enzymal group that has an essential role in the reduction, de-activation and removal of ROS as well as regulating wound healing process. In the present study, synthetic and absorbable polylactide (PLA) barrier membranes were evaluated by means of ROS activity levels during degradation in the healing periodontal flaps measuring the activity of FRSE superoxide dismutase (SOD) and catalase (CAT). Gingival biopsies taken from 10 patients allowing both guided tissue regeneration (test) and conventional flap surgery (control) before and 1 month after the operations were processed and the supernatants were studied by Mc Cord and Fridovich, Flohe and Otting, and Luck methods to measure total SOD and CAT levels respectively. A significantly increased enzyme activity of SOD and CAT was observed in both groups (phealing of periodontium at least for one-month period.

  15. Robust Active Damping Control of LCL Filtered Grid Connected Converter Based Active Disturbance Rejection Control

    DEFF Research Database (Denmark)

    Abdeldjabar, Benrabah; Xu, Dianguo; Wang, Xiongfei

    2016-01-01

    This paper deals with the problem of LCL filter resonance in grid connected inverter control. The system equations are reformulated to allow the application of the active disturbance rejection control (ADRC). The resonance, assumed unknown, is treated as a disturbance, then estimated and mitigated....... By using this new robust control, a high level of performance is achieved with a minimum complexity in the controller design, and without any adaptive algorithm. It is demonstrated that the true quality of the control system is obtained by the proposed solution. Furthermore, it is shown that this control...... is robust against parameter variations and disturbances....

  16. Shape optimisation and performance analysis of flapping wings

    KAUST Repository

    Ghommem, Mehdi

    2012-09-04

    In this paper, shape optimisation of flapping wings in forward flight is considered. This analysis is performed by combining a local gradient-based optimizer with the unsteady vortex lattice method (UVLM). Although the UVLM applies only to incompressible, inviscid flows where the separation lines are known a priori, Persson et al. [1] showed through a detailed comparison between UVLM and higher-fidelity computational fluid dynamics methods for flapping flight that the UVLM schemes produce accurate results for attached flow cases and even remain trend-relevant in the presence of flow separation. As such, they recommended the use of an aerodynamic model based on UVLM to perform preliminary design studies of flapping wing vehicles Unlike standard computational fluid dynamics schemes, this method requires meshing of the wing surface only and not of the whole flow domain [2]. From the design or optimisation perspective taken in our work, it is fairly common (and sometimes entirely necessary, as a result of the excessive computational cost of the highest fidelity tools such as Navier-Stokes solvers) to rely upon such a moderate level of modelling fidelity to traverse the design space in an economical manner. The objective of the work, described in this paper, is to identify a set of optimised shapes that maximise the propulsive efficiency, defined as the ratio of the propulsive power over the aerodynamic power, under lift, thrust, and area constraints. The shape of the wings is modelled using B-splines, a technology used in the computer-aided design (CAD) field for decades. This basis can be used to smoothly discretize wing shapes with few degrees of freedom, referred to as control points. The locations of the control points constitute the design variables. The results suggest that changing the shape yields significant improvement in the performance of the flapping wings. The optimisation pushes the design to "bird-like" shapes with substantial increase in the time

  17. Flapping Wing Flight Dynamic Modeling

    Science.gov (United States)

    2011-08-22

    future ight dynamic models. Acknowledgments I would like to thank Dr. Patil and Dr. Woolsey for giving me the opportunity to work on my thesis here...In general the results pointed towards unstable or slightly unstable eigenvalues necessitating active control but also providing opportunities for...Stream, Tech. Rep. 1326, NACA, June 1947. [22] Wagner, H., Uber die Entstehung des Dynamischen Auftriebs von Tragugeln, Bd. 5, ZAMM, Feb 1925. [23

  18. Terfenol-D-driven flaps for helicopter vibration reduction

    Science.gov (United States)

    Fenn, Ralph C.; Downer, James R.; Bushko, Dariusz A.; Gondhalekar, Vijay; Ham, Norman D.

    1993-09-01

    The utility of helicopter aviation is limited by the high vibration levels caused by interaction of each rotor blade with the wake of preceding blades. Existing full blade actuation using a swashplate has various problems such as insufficient bandwidth, limitations in the number of harmonics controlled, high maintenance, and lack of spanwise lift variation. These problems are avoided by the proposed flap operated, individual blade control system, which uses magnetostrictive actuation technology. Terfenol-D actuation has many advantages over competing technologies such as hydraulic systems, electric motors, and piezoelectric elements. These benefits include all-electric operation, simplicity and reliability, low mass, low voltage, and insensitivity to centripetal acceleration.

  19. Backup perforator flap derived from a previously transferred musculocutaneous free flap.

    Science.gov (United States)

    Topalan, Murat; Guven, Erdem; Demirtas, Yener

    2010-09-01

    Reconstruction of the lower leg commonly requires a free tissue transfer after Gustillo grade IIIB-IIIC injuries and severe postoncological resections, where, free musculocutaneous flaps (MCF) are preferred for their size and robust blood supply. The anastomoses are performed at more proximal levels to keep them away from the trauma zone. This reasonable maneuver causes the distal of the flap to cover the most critical part of the defect. Any marginal necrosis, then, ends in exposure of the bone or implant. Reported here is the use of a perforator flap derived from a previously transferred free MCF as a backup tissue. Distal marginal necrosis exposing vital structures were encountered after six free MCF transfers during the last 6 years. These were highly complicated cases in which no regional flap options were available and a second free flap was unfeasible due to recipient vessel problems. A perforator flap was elevated on the perforator vessel(s) penetrating the underlying muscle of the previous MCF and either advanced or transposed to cover the defect. Donor sites on MCF were closed primarily. Wound dehiscence that healed secondarily was observed in two cases. The knee prosthesis was removed in one case due to uncontrolled osteomyelitis. No complications were detected in other three cases. The described flap can be a leg saver whenever a previously transferred free MCF fails to cover the distal site of the defect. The flap can be advanced for 3-5 cm and allows more than 90 degrees of rotation.

  20. The prepuce free flap in 10 patients : modifications in flap design and surgical technique

    NARCIS (Netherlands)

    Werker, Paul M N

    The prepuce free flap was used in 10 oral and oropharyngeal reconstructions. During the course of this study, various modifications took place. Residual penile skin necrosis and skin island necrosis early in the series led to modification of flap design. This solved the donor-site problem by placing

  1. Rescue of Primary Incomplete Microkeratome Flap with Secondary Femtosecond Laser Flap in LASIK

    Directory of Open Access Journals (Sweden)

    E. A. Razgulyaeva

    2014-01-01

    Full Text Available For laser-assisted in situ keratomileusis (LASIK retreatments with a previous unsuccessful mechanical microkeratome-assisted surgery, some surgical protocols have been described as feasible, such as relifting of the flap or the creation of a new flap and even the change to a surface ablation procedure (photorefractive keratectomy (PRK. This case shows the use of femtosecond technology for the creation of a secondary flap to perform LASIK in a cornea with a primary incomplete flap obtained with a mechanical microkeratome. As we were unable to characterize the interface of the first partial lamellar cut, a thick flap was planned and created using a femtosecond laser platform. As the primary cut was very thick in the nasal quadrant, a piece of loose corneal tissue appeared during flap lifting which was fitted in its position and not removed. Despite this condition and considering the regularity of the new femtosecond laser cut, the treatment was uneventful. This case report shows the relevance of a detailed corneal analysis with an advanced imaging technique before performing a secondary flap in a cornea with a primary incomplete flap. The femtosecond laser technology seems to be an excellent tool to manage such cases successfully.

  2. Umbilicoplasty with 3 triangular skin flaps and excised diamond-shaped skin flap.

    Science.gov (United States)

    Takasu, Hidemi; Watanabe, Yoshio

    2010-10-01

    In cases of large umbilical hernias, standard surgical techniques have proven inadequate for diminishing the diameter of the umbilicus. We have modified the 3- and 4-triangular-skin-flap techniques to diminish the diameter of the umbilicus and achieve a cosmetically acceptable umbilicus. Umbilicoplasty was performed in 149 children (median age, 2.5 years; range, 3 months-10 years) between 2003 and 2008. We created 4 skin flaps 1.5 cm in length on the umbilicus and excised the cranial diamond-shaped skin flap. After closure of the fascial defect, the diameter of the umbilicus was diminished by suturing the opened cranial part of the diamond-shaped skin flap vertically. The tips of the 3 remaining flaps were then anchored to the closed fascia. Postoperatively, granulation tissue occurred in 18 cases (12%), transient erythema of a flap in 15 cases (10%), and bulging of a skin flap in 15 cases (10%). These complications were reduced by suturing adjoining skin flaps. No recurrent hernias were encountered. The postoperative umbilical appearance was satisfactory in all cases. This surgical technique is effective for diminishing the diameter of the umbilicus and creating a cosmetically acceptable shaped umbilicus, even for large umbilical hernias. Copyright © 2010 Elsevier Inc. All rights reserved.

  3. Use of brimonidine before LASIK with femtosecond laser-created flaps for the correction of myopia: a contralateral eye study.

    Science.gov (United States)

    Rodríguez-Galietero, Antonio; Martínez, José Vicente González; Del Buey, Angeles; Bescós, José Angel Cristóbal

    2010-01-01

    To evaluate the changes in the incidence of subconjunctival hemorrhage, hyperemia, photophobia, flap displacements, and flap retractions in myopic patients who have undergone LASIK with an IntraLase 15-kHz femtosecond laser (intraLASIK) with or without the application of brimonidine tartrate 0.2% in one eye. Two hundred eyes of 100 myopic patients were enrolled in this brimonidine tartrate fellow eye control study. These myopic patients were treated with the intraLASIK technique in both eyes. Only 1 eye was treated with brimonidine tartrate 0.2% 30 minutes before surgery. One day after surgery, subconjunctival hemorrhage, photophobia, and hyperemia were evaluated. Flap slippage and flap retractions were evaluated 1 day, 1 week, 1 month, and 3 months after surgery. Of the 100 eyes treated with brimonidine tartrate before intraLASIK, 3 (3%) eyes showed subconjunctival hemorrhage. Complex hyperemia-photophobia was found in 8 (8%) of 100 eyes immediately after the surgery compared with non-brimonidine tartrate treated eyes (79% and 92%, respectively). Eyes treated with brimonidine showed no incidence of flap complications, whereas eyes not treated with brimonidine showed 11% flap retraction. This study suggests that brimonidine tartrate 0.2% administered before intraLASIK provides a reduction in the incidence of subconjunctival hemorrhage, hyperemia, and photophobia without increasing flap complications. Copyright 2010, SLACK Incorporated.

  4. [Application of the tension skin flap with different shapes in the pedicle of the reverse neurocutaneous island flap].

    Science.gov (United States)

    Li, Meng; Lan, Xu; Zheng, Ping; Liu, Xing-Yan; Gao, Qiu-Ming; Song, Ming-Jia

    2013-08-01

    To investigate the effects of the tension skin flap with different shapes on the transplantation of the reverse neurocutaneous island flap. From January 2006 to January 2012,there were 21 patients in the study (including 15 males and 6 females), and aged from 14 to 58 years old (35 years old on average). Tension skin flaps with different shapes (triangle ,round and ellipse) were used to improve the blood supply of the reverse neurocutaneous island flap. The tension skin flaps in the pedicle were designed triangularly (10 patients), spherically (8 patients) or elliptically (3 patients). There were 5 patients with defects in the hand (the size from 5.0 cm x 2.0 cm to 8.0 cm x 5.0 cm), and 16 patients with defects in the foot and inferior segment of leg, or around the ankle (the size from 6.0 cm x 4.0 cm to 13.0 cm x 7.0 cm). And all the patients were with the tendon and bone exposed. All the flaps were reversal transplanted, including 5 dorsal neurocutaneous flaps of foot, 4 superficial peroneal neurocutaneous flaps, 4 saphenous neurocutaneous flaps, 3 sural neurocutaneous flaps, 2 superficial radial neurocutaneous flaps, 3 lateral neurocutaneous flaps of forearm. And the survival rate, appearance and sensory recovery of the flaps were analyzed. The distant part of the reversed sural neurocutaneous island flap in 1 case necrosized and healed after dressing change. The other flaps survived entirely, and the donor site all healed primarily. The follow-up time was from 3 months to 2 years (averaged 7 months), and all the flaps had recovered pain and warm sensation with perfect appearance. The tension skin flap in the pedicle can enhance the blood supply and promote survival rate of the reverse neurocutaneous island flap, and can also improve its appearance.

  5. Intraoperative local flap transforming (iLoFT method; from hachet to reading-man flap

    Directory of Open Access Journals (Sweden)

    Motoi Kato

    2017-06-01

    Full Text Available Local flaps are widely used in soft tissue reconstruction because they result in good colour and texture match. They can be quickly placed without donor site morbidity. However, it is not always easy to preoperatively design a feasible procedure, predict the final scar line or image the tension that may occur on and around the flap, especially for inexperienced surgeons. Because the elasticity of the skin varies with anatomical location and among individuals, unpredictable intraoperative design changes are sometimes required. Therefore, a preoperative back-up plan would be helpful. We evaluated the possibilities and advantages of an intraoperative switch from a hatchet flap (HF to a reading man flap (RMF procedure. Using a previously reported computer simulation with the finite element method (FEM analysis, we developed an intraoperative local flap transformation (iLoFT model.

  6. Active Control of Flow-Induced Cavity Oscillations

    Science.gov (United States)

    Garg, Sanjay; Cattafesta, Louis N., III; Chung Won, Chin

    1996-11-01

    The interaction between a cavity and the shear layer spanning its mouth can result in the generation of high levels of tonal acoustic disturbances. The excitation and growth of instabilities in the shear layer is a fundamental part of this phenomenon. Control of such shear layer instabilities was attempted in a resonant cavity flow by actuating piezoelectric flaps at the leading edge of the cavity. Under natural flow conditions, a sound pressure level (SPL) of 140 dB was measured on the cavity floor; use of the actuators resulted in a 12 dB reduction in broadband SPL. In addition, the magnitude of the primary tone was attenuated by almost 25 dB. Detailed hot-wire measurements of instability growth and flow visualization will be presented for both the uncontrolled and controlled cases. The mean flow profile changes from that of a turbulent boundary layer at separation to one representative of a self-similar shear layer further downstream; this exerts significant influence on the development of the measured u^' eigenmode profile. An initial region of exponential growth is observed followed by a region in which nonlinear effects become important resulting in finite amplitude equilibration of disturbances. In the controlled case, nonlinear mode competition appears to determine the overall amplification experienced by any one mode. Experimental results will be compared with linear and nonlinear stability theory.

  7. The adverse effect of selective cyclooxygenase-2 inhibitor on random skin flap survival in rats.

    Directory of Open Access Journals (Sweden)

    Haiyong Ren

    Full Text Available BACKGROUND: Cyclooxygenase-2(COX-2 inhibitors provide desired analgesic effects after injury or surgery, but evidences suggested they also attenuate wound healing. The study is to investigate the effect of COX-2 inhibitor on random skin flap survival. METHODS: The McFarlane flap model was established in 40 rats and evaluated within two groups, each group gave the same volume of Parecoxib and saline injection for 7 days. The necrotic area of the flap was measured, the specimens of the flap were stained with haematoxylin-eosin(HE for histologic analysis. Immunohistochemical staining was performed to analyse the level of VEGF and COX-2 . RESULTS: 7 days after operation, the flap necrotic area ratio in study group (66.65 ± 2.81% was significantly enlarged than that of the control group(48.81 ± 2.33%(P <0.01. Histological analysis demonstrated angiogenesis with mean vessel density per mm(2 being lower in study group (15.4 ± 4.4 than in control group (27.2 ± 4.1 (P <0.05. To evaluate the expression of COX-2 and VEGF protein in the intermediate area II in the two groups by immunohistochemistry test .The expression of COX-2 in study group was (1022.45 ± 153.1, and in control group was (2638.05 ± 132.2 (P <0.01. The expression of VEGF in the study and control groups were (2779.45 ± 472.0 vs (4938.05 ± 123.6(P <0.01.In the COX-2 inhibitor group, the expressions of COX-2 and VEGF protein were remarkably down-regulated as compared with the control group. CONCLUSION: Selective COX-2 inhibitor had adverse effect on random skin flap survival. Suppression of neovascularization induced by low level of VEGF was supposed to be the biological mechanism.

  8. Use of Systemic Rosmarinus Officinalis to Enhance the Survival of Random-Pattern Skin Flaps.

    Science.gov (United States)

    İnce, Bilsev; Bilgen, Fatma; Gündeşlioğlu, Ayşe Özlem; Dadacı, Mehmet; Kozacıoğlu, Sümeyye

    2016-11-01

    Skin flaps are commonly used in soft-tissue reconstruction; however, necrosis can be a frequent complication. Several systemic and local agents have been used in attempts to improve skin flap survival, but none that can prevent flap necrosis have been identified. This study aims to determine whether the use of systemic Rosmarinus officinalis (R. officinalis) extract can prevent flap necrosis and improve skin flap recovery. Animal experimentation. Thirty-five Wistar albino rats were divided in five groups. A rectangular random-pattern flaps measuring 8×2 cm was elevated from the back of each rat. Group I was the control group. In Group II, 0.2 ml of R. officinalis oil was given orally 2h before surgery. R. officinalis oil was then applied orally twice a day for a week. In Group III, R. officinalis oil was given orally twice a day for one week before surgery. At the end of the week, 0.2 mL of R. officinalis oil was given orally 2 h before surgery. In Group IV, 0.2 mL of R. officinalis oil was injected subcutaneously 2 h before surgery. After the surgery, 0.2 mL R. officinalis oil was injected subcutaneously twice a day for one week. In Group V, 0.2 mL R. officinalis oil was injected subcutaneously twice a day for one week prior to surgery. At the end of the week, one last 0.2 mL R. officinalis oil injection was administered subcutaneously 2 h before surgery. After the surgery, 0.2 mL R. officinalis oil was injected subcutaneously twice a day for one week. The mean percentage of viable surface area was significantly greater (pofficinalis has vasodilatory effects that contribute to increased skin flap survival.

  9. Clinical parameters of implants placed in healed sites using flapped and flapless techniques: A systematic review.

    Science.gov (United States)

    Llamas-Monteagudo, O; Girbés-Ballester, P; Viña-Almunia, J; Peñarrocha-Oltra, D; Peñarrocha-Diago, M

    2017-09-01

    Dental implant placement using flapless surgery is a minimally invasive technique that improves blood supply compared with flapped surgery. However, the flapless technique does not provide access to allow bone regeneration. The aim of this systematic review was to evaluate the clinical parameters following implant surgery in healed sites, using two procedures: flapped vs. flapless surgery. A detailed electronic search was carried out in the PubMed/Medline, Embase and Cochrane Library databases. The focused question was, "How do flapped and flapless surgical techniques affect the clinical parameters of dental implants placed in healed sites?". All the studies included with a prospective controlled design were considered separately, depending on whether they had been conducted on animals or humans. The following data were recorded in all the included studies: number of implants, failures, location (maxilla, mandible), type of rehabilitation (partial or single), follow-up and flap design. The variables selected for comparison in the animal studies were the following: flap design, gingival index, mucosal height, recession and probing pocket depth. In humans studies the variables were as follows: flap design, plaque index, gingival index, recession, probing pocket depth, papilla index and keratinized gingiva. Ten studies were included, six were experimental studies and four were clinical studies. Studies in animals showed better results using the flapless technique in the parameters analyzed. There is no consensus in the clinical parameters analyzed in human studies, but there is a trend to better results using flapless approach. The animal studies included in the present review show that implants placed in healed sites with a flapless approach have better clinical parameters than the flapped procedure in a short-term follow-up. In human studies, there is no consensus about which technique offer better results in terms of clinical parameters. Therefore, more research in

  10. [Repair of soft tissue defect in finger with modified reverse dorsal digital fascia flap].

    Science.gov (United States)

    Li, Zhian; Li, Zhenwu; Zhang, Guiping

    2009-06-01

    To investigate the operative method of repairing soft tissue defect of finger with modified reverse dorsal digital fascia flap and its clinical effect of preventing and treating venous crisis. From February 2005 to March 2007, 19 cases (22 fingers) with soft tissue defect of finger were treated, including 14 males (17 fingers) and 5 females (5 fingers) aged 2-62 years old (median 26 years old). There were 8 cases of cutting injury, 6 cases of crush injury, 4 cases of avulsion injury, and 1 case of hot crush injury, involving 3 thumbs, 7 index fingers, 6 middle fingers, 4 ring fingers and 2 little fingers. The size of soft tissue defect was 1.5 cm x 0.8 cm-5.5 cm x 1.5 cm, and the time from injury to operation was 2-11 hours (average 7 hours). The axis of flaps was the line of transverse striation of fingers via dominant artery. The flaps were deflected dorsally, as "b" or "d", to cover the wounds. Reverse dorsal digital fascia flaps 1.8 cm x 1.0 cm-6.0 cm x 2.0 cm in size were Radopted to repair the defects. The donor site underwent skin grafting fixation. All flaps survived, without venous acrisis and obvious swollen. The grafted skin in the donor site all survived. All patients were followed for 6-18 months (average 11 months). Postoperatively, color and texture of the grafted flaps were similar to that of normal skin, and the pulp of the fingers was normal. The two-point discrimination was 8-11 mm, and the activities of interphalangeal joint of all injured fingers were normal. The modified reverse dorsal digital fascia flap is ideal for repairing soft tissues defects of the fingers, and can decrease the occurrence of venous crisis.

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

    Science.gov (United States)

    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.

  12. Structural design optimization of a morphing trailing edge flap for wind turbine blades

    DEFF Research Database (Denmark)

    Barlas, Athanasios; Lin, Yu-Huan; Aagaard Madsen, Helge

    A flap actuation system, the Controllable Rubber Trailing Edge Flap (CRTEF), for distributed load control on a wind turbine blade had been developed in the period from 2006 to 2013 at DTU (http://www.induflap.dk/). The purpose of the presented work is to optimize the structural design...... of the flexible part of the CRTEF based on a realistic blade section geometry in order to meet the required objectives and constraints. The objectives include the deflection requirements and the energy efficiency, while the constraints include the bending stiffness of the structure, the local shape deformations...... during operation of the turbine with the flap installed are evaluated with XFOIL and included in the simulations. The model is developed first by qualitative analyses to obtain a reasonable preliminary design, and then by parametric optimization to have the final design. The parameterization...

  13. Effect of vitamin C on tissue damage and oxidative stress following tunica vaginalis flap coverage after testicular torsion.

    Science.gov (United States)

    Moghimian, Maryam; Soltani, Malihe; Abtahi, Hossein; Shokoohi, Majid

    2017-10-01

    The aim was to investigate the protective effect of vitamin C on tissue damage and oxidative stress following tunica albuginea incision with tunica vaginalis flap coverage for testicular torsion. Adult male Wistar rats were randomly divided into two experimental groups. The first group experienced 5h of testicular torsion followed by treatment with vitamin C alone, with tunica vaginalis flap coverage alone, and with both vitamin C and tunica vaginalis flap coverage along with a control group subjected to a sham procedure. The second group experienced 9h of testicular torsion followed by the same treatment options as described for the 5h group. The oxidative stress and testosterone levels were measured 24h posttreatment. The Johnsen score, diameter of the seminiferous tubules, and thickness of the seminiferous tubule epithelium were recorded 30days following the treatment. The Johnsen score, diameter of the seminiferous tubules, and thickness of the seminiferous tubule epithelium significantly increased in the 5h testicular torsion group receiving treatment with vitamin C and tunica vaginalis flap coverage compared with the group receiving tunica vaginalis flap alone. The level of testosterone decreased significantly in all groups except for the 5h testicular torsion group receiving treatment with vitamin C and tunica vaginalis flap coverage. The MDA level also decreased in the group receiving treatment with vitamin C and tunica vaginalis flap coverage compared with the group receiving tunica vaginalis flap coverage alone. The results showed that the histological parameters and testosterone levels improved with the administration of vitamin C before tunica vaginalis flap coverage in the group experiencing 5h of torsion. This may be a result of the antioxidant effect of vitamin C. No advantage was observed for the 9h group, possibly because the dosage of vitamin C was inadequate. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Autologous limbus conjunctival flap transplantation for pterygium accompaniedwith conjunctival cyst

    Directory of Open Access Journals (Sweden)

    Jin-Hua Wang

    2017-06-01

    Full Text Available AIM: To observe the efficacy of surgical excision combined with autologous limbus conjunctival flap transplantation in the treatment of pterygium accompanied with conjunctival cyst. METHODS: Totally 126 patients 188 eyes with pterygium were hospitalized in Department of Ophthalmology of Tongji Hospital of Huazhong University of Science and Technology during August 2013 and August 2015. The patients were divided into two groups: observation group(11 eyes of 11 patientswith pterygium accompanied with conjunctival cyst and control group(177 eyes of 115 patientswith primary pterygium. All patients underwent slit lamp microscope examination, anterior segment photography, and anterior segment optical coherence tomography(OCT. The size of pterygium was calculated by multiplying neck width and length of the covered corneal. All patients underwent excision combined with autologous conjunctival flap transplantation, and the resections were performed pathological section with hematoxylin and eosin staining. All patients were followed up postoperatively for 4-28mo. RESULTS: All cases in the observation group were confirmed by postoperative pathological examination. All cyst walls were complete, and containing single layer of epithelial cells. The mean size of pterygium of the observation group was 6.9±1.7mm2, and 6.3±1.8mm2 for the control group. There was no significant difference between the two groups(P>0.05. The mean postoperative healing time of observation group was 2.1±0.9d, and 1.9±0.8d for the control group. There was no significant difference between the two groups(P>0.05. Recurrence was seen in two eyes within the follow-up period in the control group, and no recurrence in the observation group. CONCLUSION: Surgical excision combined with autologous limbus conjunctival flap transplantation is a safe and effective treatment for pterygium accompanied with conjunctival cyst.

  15. First dorsal metacarpal artery flap for thumb reconstruction: a retrospective clinical study

    Science.gov (United States)

    Muyldermans, Thomas

    2009-01-01

    patient. The mean Kapandji score of the reconstructed thumb was 7.43 over 10. Using the SF-36, mean physical health of the patients scored 66.88% and mean mental health scored 70.55%. Disturbing pain and paresthesia of the flap are exceptional. The static 2-PD is more than 10 mm, and is clinically over the limit. Cortical reorientation was incomplete in all but one patient. Touch on thumb is felt on the dorsum of the index finger; however, sensation is not disturbing or interfering with the patient’s activities. Foucher described the technique débranchement–rébranchement in order to improve this problem. The postoperative total amount of motion of the reconstructed thumb was very good. The results demonstrated that the FDMCA flap has a constant anatomy and easy dissection. It has a low donor site morbidity if FTSG is used. It also shows good functional and aesthetic results. Therefore, the FDMCA flap is a first treatment of choice for defects of the proximal phalanx and proximal part of the distal phalanx of the thumb. PMID:19340522

  16. Comparison of free anterolateral thigh flaps and free muscle-musculocutaneous flaps in soft tissue reconstruction of lower extremity.

    Science.gov (United States)

    Demirtas, Yener; Kelahmetoglu, Osman; Cifci, Mehmet; Tayfur, Volkan; Demir, Ahmet; Guneren, Ethem

    2010-01-01

    The objective of this study was to compare the free muscle-musculocutaneous flaps and free perforator skin flaps used for soft tissue reconstruction of the lower extremities. Fifty-three patients whose skin and soft tissue of the lower extremities had been reconstructed were divided into two groups: a perforator flap group, reconstructed using anterolateral thigh (ALT) free flap (23 cases), and a muscle-musculocutaneous flap group, in whom latissimus dorsi and rectus abdominus muscle-musculocutaneous free flaps were used (30 cases). Postoperative complications, long-term results, and donor site morbidities were studied in the two groups. Complete flap survival was 78.3% with four total and one partial flap loss in the ALT group and 90.0% with one total and two partial failure in the muscle-musculocutaneous flap group. Muscle-musculocutaneous flaps were the flaps of choice in Gustillo grade IIIB-C injuries and for reconstruction of more proximal localizations. ALT was preferred in relatively younger patients and was typically used for coverage of the distally localized defects. Flap complication rate was significantly higher in the ALT group, but the overall complication rate was similar between the groups. ALT perforator flap is a precious option for lower extremity soft tissue reconstruction with minimal donor site morbidity. Nevertheless, the beginners should be attentive to an increased rate of flap complications with the ALT flap and free axial muscle-musculocutaneous flaps would still be the tissue of choice for coverage of leg defects for a surgeon before gaining enough experience with perforator flap dissection.

  17. Flow field of flexible flapping wings

    Science.gov (United States)

    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

  18. Vibration reduction in helicopters using active control of structural response (ACSR) with improved aerodynamic modeling

    Science.gov (United States)

    Cribbs, Richard Clay

    This dissertation describes the development of a coupled rotor/flexible fuselage aeroelastic response model including rotor/fuselage aerodynamic interactions. This model is used to investigate fuselage vibrations and their suppression using active control of structural response (ACSR). The fuselage, modeled by a three dimensional structural dynamic finite element model, is combined with a flexible, four-bladed, hingeless rotor. Each rotor blade is structurally modeled as an isotropic Euler-Bernoulli beam with coupled flap-lag-torsional dynamics assuming moderate deflections. A free wake model is incorporated into the aeroelastic response model and is validated against previous studies. Two and three dimensional sources model the fuselage aerodynamics. Direct aerodynamic influences of the rotor and wake on the fuselage are calculated by integrating pressures over the surface of the fuselage. The fuselage distorts the wake and influences the air velocities at the rotor which alters the aerodynamic loading. This produces fully coupled rotor/fuselage aerodynamic interactions. The influence of the aerodynamic refinements on vibrations is studied in detail. Results indicate that a free wake model and the inclusion of fuselage aerodynamic effects on the rotor and wake are necessary for vibration prediction at all forward speeds. The direct influence of rotor and wake aerodynamics on the fuselage plays a minor role in vibrations. Accelerations with the improved aerodynamic model are significantly greater than uniform inflow results. The influence of vertical separation between the rotor and fuselage on vibrations is also studied. An ACSR control algorithm is developed that preferentially reduces accelerations at selected airframe locations of importance. Vibration reduction studies are carried out using this improved control algorithm and a basic algorithm studied previously at UCLA. Both ACSR methods markedly reduce acceleration amplitudes with no impact on the rotor

  19. A review of wind turbine-oriented active flow control strategies

    Science.gov (United States)

    Aubrun, Sandrine; Leroy, Annie; Devinant, Philippe

    2017-10-01

    To reduce the levelized cost of energy, the energy production, robustness and lifespan of horizontal axis wind turbines (HAWTs) have to be improved to ensure optimal energy production and operational availability during periods longer than 15-20 years. HAWTs are subject to unsteady wind loads that generate combinations of unsteady mechanical loads with characteristic time scales from seconds to minutes. This can be reduced by controlling the aerodynamic performance of the wind turbine rotors in real time to compensate the overloads. Mitigating load fluctuations and optimizing the aerodynamic performance at higher time scales need the development of fast-response active flow control (AFC) strategies located as close as possible to the torque generation, i.e., directly on the blades. The most conventional actuators currently used in HAWTs are mechanical flaps/tabs (similar to aeronautical accessories), but some more innovative concepts based on fluidic and plasma actuators are very promising since they are devoid of mechanical parts, have a fast response and can be driven in unsteady modes to influence natural instabilities of the flow. In this context, the present paper aims at giving a state-of-the-art review of current research in wind turbine-oriented flow control strategies applied at the blade scale. It provides an overview of research conducted in the last decade dealing with the actuators and devices devoted to developing AFC on rotor blades, focusing on the flow phenomena that they cause and that can lead to aerodynamic load increase or decrease. After providing some general background on wind turbine blade aerodynamics and on the atmospheric flows in which HAWTs operate, the review focuses on flow separation control and circulation control mainly through experimental investigations. It is followed by a discussion about the overall limitations of current studies in the wind energy context, with a focus on a few studies that attempt to provide a global

  20. Intraoperative flap complications in lasik surgery performed by ophthalmology residents

    Directory of Open Access Journals (Sweden)

    Lorena Romero-Diaz-de-Leon

    2016-01-01

    Conclusion: Flap-related complications are common intraoperative event during LASIK surgery performed by in-training ophthalmologists. Keratometries and surgeon's first procedure represent a higher probability for flap related complications than some other biometric parameters of patient's eye.

  1. The Versatile Extended Thoracodorsal Artery Perforator Flap for Breast Reconstruction

    DEFF Research Database (Denmark)

    Jacobs, Jordan; Børsen-Koch, Mikkel; Gunnarsson, Gudjon Leifur

    2015-01-01

    BACKGROUND: The thoracodorsal artery perforator (TAP) flap is a versatile tool that can be used to reconstruct the breast. The authors use preoperative perforator mapping using color Doppler ultrasonography and present a safe, efficient harvesting technique to demonstrate reliable use of the TAP...... flap in reconstructive surgery. METHODS: A multicenter, retrospective review was performed on all patients undergoing TAP flap reconstruction from August 2011 to November 2014. Data were collected from patient records as well as outpatient interviews. RESULTS: A total of 106 TAP flaps were performed...... complications occurred in 10 of 106 (10%) cases and included hematoma (1/108), venous congestion (2/108), and partial flap necrosis (7/108). The reconstructive goal was achieved in 103 of 106 (97%) flaps. CONCLUSIONS: The TAP flap is a pedicled, fasciocutaneous flap that can be used for total breast...

  2. Coordinated Voltage Control of Active Distribution Network

    Directory of Open Access Journals (Sweden)

    Xie Jiang

    2016-01-01

    Full Text Available This paper presents a centralized coordinated voltage control method for active distribution network to solve off-limit problem of voltage after incorporation of distributed generation (DG. The proposed method consists of two parts, it coordinated primal-dual interior point method-based voltage regulation schemes of DG reactive powers and capacitors with centralized on-load tap changer (OLTC controlling method which utilizes system’s maximum and minimum voltages, to improve the qualified rate of voltage and reduce the operation numbers of OLTC. The proposed coordination has considered the cost of capacitors. The method is tested using a radial edited IEEE-33 nodes distribution network which is modelled using MATLAB.

  3. Gas turbine engine active clearance control

    Science.gov (United States)

    Deveau, Paul J. (Inventor); Greenberg, Paul B. (Inventor); Paolillo, Roger E. (Inventor)

    1985-01-01

    Method for controlling the clearance between rotating and stationary components of a gas turbine engine are disclosed. Techniques for achieving close correspondence between the radial position of rotor blade tips and the circumscribing outer air seals are disclosed. In one embodiment turbine case temperature modifying air is provided in flow rate, pressure and temperature varied as a function of engine operating condition. The modifying air is scheduled from a modulating and mixing valve supplied with dual source compressor air. One source supplies relatively low pressure, low temperature air and the other source supplies relatively high pressure, high temperature air. After the air has been used for the active clearance control (cooling the high pressure turbine case) it is then used for cooling the structure that supports the outer air seal and other high pressure turbine component parts.

  4. Breast shaping by an isolated tissue flap.

    Science.gov (United States)

    Voigt, Matthias; Andree, C

    2006-01-01

    Breast reshaping surgery for tuberous breast, breast reduction, and mastopexy procedures aim to keep the gained shape for a long time. In breast reduction, the surgeon must avoid loss of fullness in the upper pole, descent of the breast mass known as secondary dropout, and relapsed shape of the repaired tuberous breasts. As described in their clinical report, the authors use a caudally based thoracic wall flap to avoid these problems. The blood supply to the breast comes from two main sources: the mammary internal and lateral arteries. Because of vessels constantly perforating the pectoralis major muscle, it is possible to isolate a caudally based thoracic wall flap. These vessels originate from intercostal arteries as anteromedial intercostal perforators, and from the thoracoacromial artery as in the skin paddle of the pectoralis major muscle flap. This flap is long enough to reach every part of the breast where it is needed. Between January 2002 and June 2005, 64 patients underwent procedures in which the caudally based thoracic wall flap was used.

  5. The forked flap repair for hypospadias

    Directory of Open Access Journals (Sweden)

    Anil Chadha

    2012-01-01

    Full Text Available Context: Despite the abundance of techniques for the repair of Hypospadias, its problems still persist and a satisfactory design to correct the penile curvature with the formation of neourethra from the native urethral tissue or genital or extragenital tissues, with minimal postoperative complications has yet to evolve. Aim: Persisting with such an endeavor, a new technique for the repair of distal and midpenile hypospadias is described. Materials and Methods: The study has been done in 70 cases over the past 11 years. The "Forked-Flap" repair is a single stage method for the repair of such Hypospadias with chordee. It takes advantage of the rich vascular communication at the corona and capitalizes on the established reliability of the meatal based flip-flap. The repair achieves straightening of the curvature of the penis by complete excision of chordee tissue from the ventral surface of the penis beneath the urethral plate. The urethra is reconstructed using the native plate with forked flap extensions and genital tissue relying on the concept of meatal based flaps. Water proofing by dartos tissue and reinforcement by Nesbit′s prepucial tissue transfer completes the one stage procedure. Statistical Analysis: An analysis of 70 cases of this single stage technique of repair of penile hypospadias with chordee, operated at 3 to 5 years of age over the past 11 years is presented. Results and Conclusion: The Forked Flap gives comparable and replicable results; except for a urethrocutaneous fistula rate of 4% no other complications were observed.

  6. Hardware removal after osseous free flap reconstruction.

    Science.gov (United States)

    Day, Kristine E; Desmond, Renee; Magnuson, J Scott; Carroll, William R; Rosenthal, Eben L

    2014-01-01

    Identifying risk factors for hardware removal in patients undergoing mandibular reconstruction with vascularized osseous free flaps remains a challenge. The purpose of this study is to identify potential risk factors, including osteocutaneous radial forearm versus fibular flap, for need for removal and to describe the fate of implanted hardware. Case series with chart review Setting Academic tertiary care medical center. Two hundred thirteen patients undergoing 227 vascularized osseous mandibular reconstructions between the years 2004 and 2012. Data were compiled through a manual chart review, and patients incurring hardware removals were identified. Thirty-four of 213 evaluable vascularized osseous free flaps (16%) underwent surgical removal of hardware. The average length of time to removal was 16.2 months (median 10 months), with the majority of removals occurring within the first year. Osteocutaneous radial forearm free flaps (OCRFFF) incurred a slightly higher percentage of hardware removals (9.9%) compared to fibula flaps (6.1%). Partial removal was performed in 8 of 34 cases, and approximately 38% of these required additional surgery for removal. Hardware removal was associated with continued tobacco use after mandibular reconstruction (P = .03). Removal of the supporting hardware most commonly occurs from infection or exposure in the first year. In the majority of cases the bone is well healed and the problem resolves with removal.

  7. Active Aircraft Pylon Noise Control System

    Science.gov (United States)

    Thomas, Russell H. (Inventor); Czech, Michael J. (Inventor); Elmiligui, Alaa A. (Inventor)

    2017-01-01

    An active pylon noise control system for an aircraft includes a pylon structure connecting an engine system with an airframe surface of the aircraft and having at least one aperture to supply a gas or fluid therethrough, an intake portion attached to the pylon structure to intake a gas or fluid, a regulator connected with the intake portion via a plurality of pipes, to regulate a pressure of the gas or fluid, a plenum chamber formed within the pylon structure and connected with the regulator, and configured to receive the gas or fluid as regulated by the regulator, and a plurality of injectors in communication with the plenum chamber to actively inject the gas or fluid through the plurality of apertures of the pylon structure.

  8. Active Flow Control on a Generic Trapezoidal Wing Planform

    Science.gov (United States)

    Wygnanski, Israel; Little, Jesse; Roentsch, Bernhard; Endrikat, Sebastian

    2016-11-01

    Fluidic oscillators are employed to increase the lift and improve longitudinal stability of a generic trapezoidal wing having aspect ratio of 1.15 and taper ratio of 0.27. Actuation is applied along the flap hinge which spans the entire wing and is parallel to the trailing edge. Experiments are conducted at a Reynolds number of 1 . 7 ×106 for a wide range of incidence (-8° o to 24°) and flap deflection angles (0° to 75°). Baseline flow on the deflected flap is directed inboard prior to boundary layer separation, but changes to outboard with increasing incidence and flap deflection. The attached spanwise flow can be redirected using a sparse distribution of fluidic oscillators acting as a fluidic fence. However, the majority of lift enhancement and pitch break improvement is accomplished using a more dense distribution of actuators which attaches separated flow to the flap. Integral force and moment results are supported by surface flow visualization, pressure sensitive paint and PIV which reveal unique flow features such as a hinge vortex analogous to the leading edge vortex on a forward swept wing and the possible existence of an absolute instability in a plane parallel to the highly deflected flap. Supported by U.S. Office of Naval Research (N00014-14-1-0387).

  9. Perforator plus flaps: Optimizing results while preserving function and esthesis

    Directory of Open Access Journals (Sweden)

    Mehrotra Sandeep

    2010-01-01

    Full Text Available Background: The tenuous blood supply of traditional flaps for wound cover combined with collateral damage by sacrifice of functional muscle, truncal vessels, or nerves has been the bane of reconstructive procedures. The concept of perforator plus flaps employs dual vascular supply to flaps. By safeguarding perforators along with supply from its base, robust flaps can be raised in diverse situations. This is achieved while limiting collateral damage and preserving nerves, vessels, and functioning muscle with better function and aesthesis. Materials and Methods: The perforator plus concept was applied in seven different clinical situations. Functional muscle and fasciocutaneous flaps were employed in five and adipofascial flaps in two cases, primarily involving lower extremity defects and back. Adipofascial perforator plus flaps were employed to provide cover for tibial fracture in one patients and chronic venous ulcer in another. Results: All flaps survived without any loss and provided long-term stable cover, both over soft tissue and bone. Functional preservation was achieved in all cases where muscle flaps were employed with no clinical evidence of loss of power. There was no sensory loss or significant oedema in or distal to the flap in both cases where neurovascular continuity was preserved during flap elevation. Fracture union and consolidation were satisfactory. One patient had minimal graft loss over fascia which required application of stored grafts with subsequent take. No patient required re-operation. Conclusions: Perforator plus concept is holistic and applicable to most flap types in varied situations. It permits the exercise of many locoregional flap options while limiting collateral functional damage. Aesthetic considerations are also addressed while raising adipofascial flaps because of no appreciable donor defects. With quick operating times and low failure risk, these flaps can be a better substitute to traditional flaps and at

  10. Identifying Sources of Lift Production on Rapidly Pitching Trailing Edge Flaps

    Science.gov (United States)

    Mancini, Peter; Jones, Anya; Ol, Michael

    2016-11-01

    Recent work has delved into the design and quantification of the aerodynamic response of large trailing edge flaps. Ultimately, these flaps would be used as a control mechanism to provide an immediate aerodynamic response to the vehicle, e.g. in the event of a gust encounter. The present work explores the individual sources and contributions of lift in the case of a large, rapidly pitching trailing edge flap. The flap is 50% of the chord length, and thus produces large acceleration and pitch rate terms that dominate the lift production. In the experiment and simulations presented here, the front element remains fixed at a constant angle of attack, while the rear element pitches to a final incidence angle, which in this study ranges from 5 degrees to 40 degrees. Although the front element does not pitch throughout the motion, it is important to consider the time history of the lift distribution on that wing section and assess whether the rapid pitching of the aft element affects the forces experienced on the stationary front element. These results are then used to suggest a simplified method for predicting lift production of a wing with a large trailing flap.

  11. A study on the aerodynamic characteristics of airfoil in the flapping adjustment stage during forward flight

    Science.gov (United States)

    Luo, Pan; Zhang, Xingwei; Huang, Panpan; Xie, Lingwang

    2017-10-01

    The aim of this study is to investigate the aerodynamic characteristics of a flapping airfoil in the adjustment stage between two specific flight patterns during the forward flight. Four flapping movement models in adjustment stage are firstly established by using the multi-objective optimization algorithm. Then, a numerical experiment is carried out by using finite volume method to solve the two-dimensional time-dependent incompressible Navier-Stokes equations. The attack angles are selected from ‑5° to 7.5° with an increase of 2.5°. The results are systematically analyzed and special attention is paid to the corresponding changes of aerodynamic forces, vortex shedding mechanism in the wake structure and thrust efficiency. Present results show that output aerodynamic performance of flapping airfoil can be improved by the increasement of amplitude and frequency in the flapping adjustment stage, which further validates and complements previous studies. Moreover, it is also show that the manner using multi-objective optimization algorithm to generate a movement model in adjustment stage, to connect other two specific plunging motions, is a feasible and effective method. Current study is dedicated to providing some helpful references for the design and control of artificial flapping wing air vehicles.

  12. Modified first dorsal metacarpal artery island flap for sensory reconstruction of thumb pulp defects.

    Science.gov (United States)

    Wang, H; Chen, C; Li, J; Yang, X; Zhang, H; Wang, Z

    2016-02-01

    Restoration of tactile sensation after reconstruction of a thumb pulp defect is import for hand function. We describe our clinical experience using a modified first dorsal metacarpal artery island flap innervated by the radial dorsal branch of the proper digital nerve and the terminal branch of the superficial radial nerve in 20 consecutive cases. The results were compared with 25 patients treated by the conventional Foucher's first dorsal metacarpal artery flap without nerve repair. At the final follow-up, flap sensation was assessed using static two-point discrimination and Semmes-Weinstein monofilament testing. All flaps survived uneventfully in both groups. At the final follow-up, the mean values for static two-point discrimination and Semmes-Weinstein monofilament testing in the study group were significantly different from the values in the control group. The modified first dorsal metacarpal artery island flap provides a reliable and simple option for sensory reconstruction of thumb pulp defects. Therapeutic, level III. © The Author(s) 2015.

  13. Chronic Open Infective Lateral Malleolus Bursitis Management Using Local Rotational Flap

    Directory of Open Access Journals (Sweden)

    Yong-Beom Lee

    2017-01-01

    Full Text Available Background. Using a sinus tarsi rotational flap is an uncommon approach to treating chronic open infective lateral malleolus bursitis. Methods. We treated eight patients, including six males, using this approach. First, we debrided all the infected tissues and used a negative pressure wound closure system where needed. After acute infection had been controlled, the local rotational flap was used for cases where the wound could not be closed by a simple suture or bone exposure. The rotational flap was detached with a curved skin incision at the sinus tarsi next to the open wound and sutured to the defect, paying careful attention to the superficial peroneal nerve. The donor site was managed with a split-thickness skin graft. Results. The patients’ mean age was 74.1 years. Six patients had a wound after suppurative infection, but two patients had ulcer-type bursitis. Six patients demonstrated full flap healing, but two patients had venous congestion necrosis. Conclusion. A sinus tarsi rotational flap is a useful method to ensure healing and coverage of chronic open lateral malleolus bursitis, especially for small to medium wounds with cavity and bone exposure.

  14. Ridge alterations following immediate implant placement in the dog: flap versus flapless surgery.

    Science.gov (United States)

    Blanco, Juan; Nuñez, Vanesa; Aracil, Luis; Muñoz, Fernando; Ramos, Isabel

    2008-07-01

    To assess the healing process after flap or flapless surgery in immediate implant placement. This study was carried out on five Beagle dogs. Four implants were placed in the lower jaw in each dog immediately after tooth extraction. Flap surgery was performed before the extraction on one side (control), and flapless on the contrary (test). After 3 months of healing, the dogs were sacrificed and prepared for histological analysis. Ten implants were placed in each group. Two failed (one of each group). The percentage of bone-implant contact was very similar in both groups: 64.8% and 65.1% for the flap and the flapless group, respectively. The difference between the mean distance from the peri-implant mucosa margin to the first bone-implant contact at the buccal aspect was statistically significant between both groups (3.02 mm. flapless and 3.69 mm. flap group). The mean first bone-implant contact at the buccal aspect was located in relation to the sand-blasted and acid-etched level at 0.82 mm for the flapless group and 1.33 mm for the flap group. This difference was not statistically significant. Flapless immediate implant surgery produces a significant reduction in the vestibular biologic width and a minor reduction in buccal bone plate resorption.

  15. Vertical and horizontal ridge alterations after tooth extraction in the dog: flap vs. flapless surgery.

    Science.gov (United States)

    Blanco, Juan; Mareque, Santiago; Liñares, Antonio; Muñoz, Fernando

    2011-11-01

    To compare ridge alterations after flap and flapless tooth extraction in the vertical and horizontal dimension in the dog model. This study was carried out on five Beagle dogs. Four extractions were performed in the lower jaw of each dog (two per side. Pm3, Pm4). At the time of tooth extraction, flap surgery was performed on one side (control group). On the contra-lateral side, a flapless extraction was performed (test group). Mesial sockets were left untreated on both sides. After 3 months of healing, the dogs were sacrificed and prepared for histological analysis. Ten samples were evaluated on each group. The vertical difference in height between the buccal and lingual crest was 1.48 mm for the flap, and 1.22 mm for the flapless group. The horizontal dimension of the ridge was 4.41 mm (at 1 mm from the crest), 5.72 mm (at 3 mm from the crest) and 6.67 mm (at 5 mm form the crest) in the flap group. In the flapless group, the measurements were 4.5, 5.58 mm and 6.44 at 1, 3 and 5 mm from the crest, respectively. Evaluating ridge alterations in the vertical and horizontal dimension after 3 months of healing following tooth extraction, results for the flap and the flapless group were very similar. © 2011 John Wiley & Sons A/S.

  16. The pudendal thigh flap as YV advanced flap for the release of perineum burns contractures.

    Science.gov (United States)

    Benito, P; De Juan, A; Cano, M

    2012-05-01

    Contractures secondary to burns affecting the perineum often cause severe functional, aesthetic and psychological harm. Many different surgical techniques are used to treat such conditions ranging from grafts, to triangular plasty transposition or advancement flaps of local tissue. It is usually advisable to use a flap or local perineoplasty because the quality of reconstruction tends to be better and the risk of reoccurrence of the contracture is lower. The pudendal thigh fasciocutaneous (PTF) flap is an axial patterned and sensate flap based on the groin crease. It has frequently been used for perineal and vaginal reconstructions. Technically, it is not difficult to perform, with a well tolerated scar located in the inguinal crease, and it is characterized by its thinness and its ready adaptation to the defects, and because it maintains sensitivity. To the best of our knowledge, no previous case of perineal contracture treatment has been reported with the use of a PTF flap harvested as an YV advanced flap. Here we report the case of a patient with a severe contracture who was treated using the flap described above, a satisfactory result being achieved. Copyright © 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  17. Reconstruction of Postburn Contracture of the Forefoot Using the Anterolateral Thigh Flap.

    Science.gov (United States)

    Lee, Sang Hyun; An, Sung Jin; Kim, Nu Ri; Kim, Um Ji; Kim, Jeung Il

    2016-12-01

    Severe forefoot deformities, particularly those involving the dorsum of the foot, cause inconvenience in daily activities of living including moderate pain on the dorsal aspect of the contracted foot while walking and difficulty in wearing nonsupportive shoes due to toe contractures. This paper presents clinical results of reconstruction of severe forefoot deformity using the anterolateral thigh (ALT) free flap. Severe forefoot deformities were reconstructed using ALT flaps in 7 patients (8 cases) between March 2012 and December 2015. The mean contracture duration was 28.6 years. All the flaps survived completely. The size of the flaps ranged from 8 cm × 5 cm to 19 cm × 8 cm. The mean follow-up period was 10 months (range, 7 to 15 months). There was no specific complication at both the recipient and donor sites. There was one case where the toe contracture could not be completely treated after surgery. All of the patients were able to wear shoes and walk without pain. Also, the patients were highly satisfied with cosmetic results. The ALT flap may be considered ideal for the treatment of severe forefoot deformity.

  18. The isolated perfused human skin flap model: A missing link in skin penetration studies?

    Science.gov (United States)

    Ternullo, Selenia; de Weerd, Louis; Flaten, Gøril Eide; Holsæter, Ann Mari; Škalko-Basnet, Nataša

    2017-01-01

    Development of effective (trans)dermal drug delivery systems requires reliable skin models to evaluate skin drug penetration. The isolated perfused human skin flap remains metabolically active tissue for up to 6h during in vitro perfusion. We introduce the isolated perfused human skin flap as a close-to-in vivo skin penetration model. To validate the model's ability to evaluate skin drug penetration the solutions of a hydrophilic (calcein) and a lipophilic (rhodamine) fluorescence marker were applied. The skin flaps were perfused with modified Krebs-Henseleit buffer (pH7.4). Infrared technology was used to monitor perfusion and to select a well-perfused skin area for administration of the markers. Flap perfusion and physiological parameters were maintained constant during the 6h experiments and the amount of markers in the perfusate was determined. Calcein was detected in the perfusate, whereas rhodamine was not detectable. Confocal images of skin cross-sections shoved that calcein was uniformly distributed through the skin, whereas rhodamine accumulated in the stratum corneum. For comparison, the penetration of both markers was evaluated on ex vivo human skin, pig skin and cellophane membrane. The proposed perfused flap model enabled us to distinguish between the penetrations of the two markers and could be a promising close-to-in vivo tool in skin penetration studies and optimization of formulations destined for skin administration. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Aerothermal Assment Of The Expert Flap In The SCIROCCO Wind Tunnel

    Science.gov (United States)

    Walpot, L.; Di Clemente, M.; Vos, J.; Etchells, J.; Trifoni, E.; Thoemel, J.; Gavira, J.

    2011-05-01

    In the frame of the “In-Flight Test Measurement Techniques for Aerothermodynamics” activity of the EXPERT Program, the EXPERT Instrumented Open Flap Assembly experiment has the objective to verify the design/sensor integration and validate the CFD tools. Ground based measurements were made in Europe’s largest high enthalpy plasma facility, Scirocco in Italy. Two EXPERT flaps of the flight article, instrumented with 14 thermocouples, 5 pressure ports, a pyrometer and an IR camera mounted in the cavity instrumented flap will collect in-flight data. During the Scirocco experiment, an EXPERT flap model identical to the flight article was mounted at 45 deg on a holder including cavity and was subjected to a hot plasma flow at an enthalpy up to 11MJ/kg at a stagnation pressure of 7 bar. The test model sports the same pressure sensors as the flight article. Hypersonic state-of-the-art codes were then be used to perform code-to-code and wind tunnel-to-code comparisons, including thermal response of the flap as collected during the tests by the sensors and camera.

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

    Science.gov (United States)

    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

  1. [Clinical study on effect of keeping perioperative normal body temperature on skin flap survival].

    Science.gov (United States)

    Xu, Hongwei; Luo, Jun; Huang, Fuguo

    2007-07-01

    To investigate the effect of perioperative body temperature on the survival of skin flap grafting. From July 2005 to November 2006, 50 cases of I-II grade patients undergoing elective skin flap grafting were randomly divided 2 groups. Pharyngeal temperature (PT) and skin temperature (ST) were monitored and recorded every 15 minutes. Operative time, anesthetic time, time from the end of operation to extubation, the volume of blood transfusion, the volume of fluid transfusion and the flap survival 7 days after operation were recorded. In the experimental group, the body temperature was maintained in normal range with water market and forced air heater. In the control group, the body temperature was only monitored without any treatment. Results There were no significant differences in operating room temperature, operative time, anesthetic time, the volume of blood transfusion and fluid transfusion between 2 groups (P > 0.05). After induction, PT decreased gradually in both groups during the first 45 minutes, compared with the time point of intubation (P 0.05); and ST rose in both groups during the first 45 minutes, compared with the time point of intubation (P 0.05). In the control group, both PT and ST decreased gradually and time-dependently compared with the time point of intubation (P skin flap grafts survived in the experimental group, and skin flap grafts necrosed in 2 cases in the control group. Keeping normal body temperature can improve the survival of skin flap grafting. Therefore, the body temperature should be monitored and maintained in a normal range.

  2. Girth augmentation of the penis using flaps "Shaeer's augmentation phalloplasty": the superficial circumflex iliac flap.

    Science.gov (United States)

    Shaeer, Osama

    2014-07-01

    Penile girth augmentation can be achieved by various techniques, among which are liposuction injection, synthetic grafts, and autologous grafts, with variable outcome, mostly related to viability and receptivity of the tissue used for augmentation. Flaps are considered superior to grafts considering their uninterrupted blood supply. The current work describes long-term experience with penile girth augmentation using the superficial circumflex iliac artery and vein (SCIAV) flap. SCIAV flap was used for penile girth augmentation in 40 candidates who followed up for a minimum of 18 months. The flap was mobilized from the groin region. The penis was pulled out of a peno-pubic incision. The flap was tunneled under the pubic region to emerge at the base of the penis and was sutured to the subcoronal area and on either sides of the spongiosum. Another session was required for either de-bulking of the oversized flap (four overweight candidates), flap pedicle (n = 6), or for donor site scar revision (n = 11). Gain in girth in centimeters was evaluated. Excluding dropouts (n = 8) and participants who had encountered de-bulking of the flap body (n = 4), 40 participants had a preoperative average flaccid girth (AFG) of 9.3 ± 1.1 cm. Immediately postoperative AFG was 14.9 ± 1.1 cm (P < 0.001). Postoperative AFG at the final follow-up visit (a minimum of 18 months) was 14.5 ± 1.1 cm (55.6% gain compared with baseline, P < 0.001). SCIAV flap is a reliable option for long-lasting and sizable penile girth augmentation. One-stage augmentation is more suited for non-obese candidates. A second session may be indicated in overweight candidates or for scar revision. © 2014 International Society for Sexual Medicine.

  3. Missile flight control using active flexspar actuators

    Science.gov (United States)

    Barrett, Ronald M.; Gross, R. Steven; Brozoski, Fred

    1995-05-01

    A new type of subsonic missile flight control surface using piezoelectric flexspar actuators is presented. The flexspar design uses an aerodynamic shell which is pivoted at the quarter-chord about a graphite main spar. The shell is pitched up and down by a piezoelectric bender element which is rigidly attached to a base mount and allowed to rotate freely at the tip. The element curvature, shell pitch deflection and torsional stiffness are modeled using laminated plate theory. A one-third scale TOW 2B missile model was used as a demonstration platform. A static wing of the missile was replaced with an active flexspar wing. The 1' X 2.7' active flight control surface was powered by a bi-morph bender with 5-mil PZT-5H sheets. Bench and wind tunnel testing showed good correlation between theory and experiment and static pitch deflections in excess of +/- 14 degree(s). A natural frequency of 78.5 rad/s with a break frequency of 157 rad/s was measured. Wind tunnel tests revealed no flutter or divergence tendencies. Maximum changes in lift coefficient were measured at (Delta) CL equals +/- .73 which indicates that terminal and initial missile load factors may be increased by approximately 3.1 and 12.6 g's respectively, leading to a greatly reduced turn radius of only 2,400 ft.

  4. scrotal reconstruction with a pedicled gracilis muscle flap after ...

    African Journals Online (AJOL)

    better functional and cosmetic outcomes. Muscle and myocutaneous flaps like gracilis, rectus abdominis, split gluteus maximus flaps are needed for large skin defects with deep pockets or cavities to eliminate the dead space (2,3). The pedicled or free greater omental flap as well as scrotal tissue expansion have also been ...

  5. Study of design parameters of flapping-wings

    NARCIS (Netherlands)

    Wang, Q.; Goosen, J.F.L.; Van Keulen, F.

    2014-01-01

    As one of the most important components of a flapping-wing micro air vehicle (FWMAV), the design of an energy-efficient flapping-wing has been a research interest recently. Research on insect flight from different perspectives has been carried out, mainly with regard to wing morphology, flapping

  6. Prospective evaluation of outcome measures in free-flap surgery.

    LENUS (Irish Health Repository)

    Kelly, John L

    2004-08-01

    Free-flap failure is usually caused by venous or arterial thrombosis. In many cases, lack of experience and surgical delay also contribute to flap loss. The authors prospectively analyzed the outcome of 57 free flaps over a 28-month period (January, 1999 to April, 2001). The setting was a university hospital tertiary referral center. Anastomotic technique, ischemia time, choice of anticoagulant, and the grade of surgeon were recorded. The type of flap, medications, and co-morbidities, including preoperative radiotherapy, were also documented. Ten flaps were re-explored (17 percent). There were four cases of complete flap failure (6.7 percent) and five cases of partial failure (8.5 percent). In patients who received perioperative systemic heparin or dextran, there was no evidence of flap failure (p = .08). The mean ischemia time was similar in flaps that failed (95 +\\/- 29 min) and in those that survived (92 +\\/- 34 min). Also, the number of anastomoses performed by trainees in flaps that failed (22 percent), was similar to the number in flaps that survived (28 percent). Nine patients received preoperative radiotherapy, and there was complete flap survival in each case. This study reveals that closely supervised anastomoses performed by trainees may have a similar outcome to those performed by more senior surgeons. There was no adverse effect from radiotherapy or increased ischemia time on flap survival.

  7. Peroperative evaluation of vascularity of various flaps by fluorescein technique

    Directory of Open Access Journals (Sweden)

    Bhattacharya V

    2006-01-01

    Full Text Available Background: The viability of any pedicled flap depends upon its vascularity. When a flap is dissected it becomes relatively ischaemic. Ultimately, the viability of the flap depends on the vessels incorporated in the pedicle and their perfusion capacity. There are different techniques to evaluate the blood supply of a flap. Aims: This study deals with experimental and clinical efficiency of fluorescein dye technique to evaluate the vascularity of flaps of various compositions. Materials and Methods: The experimental study was conducted on rats to standardize the technique. Thereafter clinical evaluation was conducted for different flaps namely fasciocutaneous, skeletonized perforator based fasciocutaneous, adipofascial, fasciocutaneous flap with adipofascial extension, fasciocutaneous flap with fascial extension and fasciocutaneous flap with split fascial extension. Conclusions: The paper deals in detail with the technique and method of documentation of a fluorescein study on flaps both experimentally and clinically. The appearance of fluorescein on both the surfaces and distal margin of the flap confirmed the adequacy of vascularity soon after dissection of the flaps. It was found to be an easy, safe and reliable objective method.

  8. Propeller Flap for Complex Distal Leg Reconstruction: A Versatile ...

    African Journals Online (AJOL)

    Reverse sural artery fasciocutaneous flap has become a workhorse for the reconstruction of distal leg soft ... A Versatile Alternative when Reverse Sural Artery Flap is. Not Feasible. Samuel A. Ademola, Afieharo I. .... flaps that were raised in the patient and the logistics of limb positioning after application of external fixators ...

  9. The management of pelvic pressure ulcers by myocutaneous flaps ...

    African Journals Online (AJOL)

    The sex ratio was 5 men for 4 women 10 sacral ulcers were treated by gluteus maximus myocutaneous flaps, 10 trochanteric and 4 ischiatic ulcers were covered by tensor fascia lata myocutaneous flaps. The cure rate was 100%. The main complications were: infection (63.5%), serous fluid discharge (21.05%), and flap ...

  10. Posttraumatic eyebrow reconstruction with hair-bearing temporoparietal fascia flap

    Science.gov (United States)

    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. PMID:25993077

  11. Double papilla flap technique for dual purpose

    Directory of Open Access Journals (Sweden)

    P Mohan Kumar

    2012-01-01

    Full Text Available Marginal tissue recession exposes the anatomic root on the teeth, which gives rise to -common patient complaints. It is associated with sensitivity, tissue irritation, cervical abrasions, and esthetic concerns. Various types of soft tissue grafts may be performed when recession is deep and marginal tissue health cannot be maintained. Double papilla flap is an alternative technique to cover isolated recessions and correct gingival defects in areas of insufficient attached gingiva, not suitable for a lateral sliding flap. This technique offers the advantages of dual blood supply and denudation of interdental bone only, which is less susceptible to permanent damage after surgical exposure. It also offers the advantage of quicker healing in the donor site and reduces the risk of facial bone height loss. This case report presents the advantages of double papilla flap in enhancing esthetic and functional outcome of the patient.

  12. Biological width following immediate implant placement in the dog: flap vs. flapless surgery.

    Science.gov (United States)

    Blanco, Juan; Alves, Célia Coutinho; Nuñez, Vanesa; Aracil, Luis; Muñoz, Fernando; Ramos, Isabel

    2010-06-01

    To assess the marginal soft tissue healing process after flap or flapless surgery in immediate implant placement in a dog model. This study was carried out on five Beagle dogs. Four implants were placed in the lower jaw in each dog immediately after tooth extraction. Flap surgery was performed before the extraction on one side (control) and flapless on the other (test). After 3 months of healing, the dogs were sacrificed and prepared for histological analysis. Ten implants were placed in each group. Two failed (one of each group). The length of the junctional epithelium in the flapless group was 2.54 mm (buccal) and 2.11 mm (lingual). In the flap group, the results were very similar: 2.59 mm (buccal) and 2.07 mm (lingual), with no significant differences observed between the groups. The length of the connective tissue in the flapless group was 0.68 mm (buccal) and 0.54 mm (lingual), and 1.09 mm at the buccal and 0.91 mm at the lingual aspect in the flap group, with no significant differences between groups. The difference between the mean distance from the peri-implant mucosa margin to the first bone-implant contact at the buccal aspect was significant between both groups (3.02 mm-flapless and 3.69 mm flap group). However, this difference was mostly due to the Pm3 group (flapless: 2.95/flap: 3.76) because no difference could be detected in the Pm4 group. Both groups showed minimal recession, with no significant differences between groups (flapless group - 0.6 mm buccal and 0.42 mm lingual; flap group - 0.67 and 0.13 mm). The clinical evaluation of immediate implant placement after 3 months of healing indicated that buccal soft tissue retraction was lower in the flapless group than in the flap group, without significant differences. The mean values of the biological width longitudinal dimension at the buccal aspect were higher in the flap group than in the flapless group, this difference being mostly due to the Pm3, probably because of a thinner biotype in this

  13. Internal control activities in small Turkish companies

    Directory of Open Access Journals (Sweden)

    Ismail Bilgi

    2017-01-01

    Full Text Available The purpose of this paper is to present major outcomes from an empirical study concerning internal control activities in small Turkish companies, as to propose the improvement guidelines. Methods of analysis and synthesis, descriptive statistics, and statistical comparison were used. The collected data was processed with the help of the SPSS software. Тhe study is limited to organizations based in the European part of Turkey. Most of them operate in areas around large cities, such as Istanbul, Edirne, Kırklareli, and Tekirdağ. They employ on average 19-20 people and have a turnover of about TRY 3 million (≈€715,000, https://sdw.ecb.europa.eu on average. The survey concentrates mainly on small family businesses, which have been present on the market for more than ten years, with managers of good education and other characteristics that presuppose availability of internal control systems. The research results were used to compile main points of a SWOT analysis, as a part of the broader effort to help modernizing the internal control system in Turkish small businesses.

  14. Getting Started with PEAs-Based Flapping-Wing Mechanisms for Micro Aerial Systems

    Directory of Open Access Journals (Sweden)

    José Carlos Durán Hernández

    2016-05-01

    Full Text Available This paper introduces recent advances on flapping-wing Micro and Nano Aerial Vehicles (MAVs and NAVs based on Piezoelectric Actuators (PEA. Therefore, this work provides essential information to address the development of such bio-inspired aerial robots. PEA are commonly used in micro-robotics and precise positioning applications (e.g., micro-positioning and micro-manipulation, whereas within the Unmanned Aerial Vehicles (UAVs domain, motors are the classical actuators used for rotary or fixed-wing configurations. Therefore, we consider it pertinent to provide essential information regarding the modeling and control of piezoelectric cantilever actuators to accelerate early design and development stages of aerial microrobots based on flapping-wing systems. In addition, the equations describing the aerodynamic behavior of a flapping-wing configuration are presented.

  15. Hybrid immersed boundary method for airfoils with a trailing-edge flap

    DEFF Research Database (Denmark)

    Zhu, Wei Jun; Behrens, Tim; Shen, Wen Zhong

    2013-01-01

    In this paper, a hybrid immersed boundary technique has been developed for simulating turbulent flows past airfoils with moving trailing-edge flaps. Over the main fixed part of the airfoil, the equations are solved using a standard body-fitted finite volume technique, whereas the moving trailing...... boundaries the k-ωturbulence model is modified and adapted to the local conditions associated with the immersed boundary method. The obtained results show that the hybrid approach is an efficient and accurate method for solving turbulent flows past airfoils with a trailing-edge flap and that flow control...... using an adjustable trailing-edge flap is an efficient way to regulate the aerodynamic loading on airfoils. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved....

  16. Reflection-plane tests of spoilers on an advanced technology wing with a large Fowler flap

    Science.gov (United States)

    Wentz, W. H., Jr.; Volk, C. G., Jr.

    1976-01-01

    Wind tunnel experiments were conducted to determine the effectiveness of spoilers applied to a finite-span wing which utilizes the GA(W)-1 airfoil section and a 30% chord full-span Fowler flap. A series of spoiler cross sectioned shapes were tested utilizing a reflection-plane model. Five-component force characteristics and hinge moment measurements were obtained. Results confirm earlier two-dimensional tests which showed that spoilers could provide large lift increments at any flap setting, and that spoiler control reversal tendencies could be eliminated by providing a vent path from lower surface to upper surface. Performance penalties due to spoiler leakage airflow were measured.

  17. The transversely split gracilis twin free flaps

    Directory of Open Access Journals (Sweden)

    Upadhyaya Divya

    2010-01-01

    Full Text Available The gracilis muscle is a Class II muscle that is often used in free tissue transfer. The muscle has multiple secondary pedicles, of which the first one is the most consistent in terms of position and calibre. Each pedicle can support a segment of the muscle thus yielding multiple small flaps from a single, long muscle. Although it has often been split longitudinally along the fascicles of its nerve for functional transfer, it has rarely been split transversely to yield multiple muscle flaps that can be used to cover multiple wounds in one patient without subjecting him/her to the morbidity of multiple donor areas .

  18. Early Mobilization after Free-flap Transfer to the Lower Extremities: Preferential Use of Flow-through Anastomosis.

    Science.gov (United States)

    Miyamoto, Shimpei; Kayano, Shuji; Fujiki, Masahide; Chuman, Hirokazu; Kawai, Akira; Sakuraba, Minoru

    2014-03-01

    Prolonged bed rest and elevation have traditionally been considered necessary after free-flap transfer to the lower extremities. In this retrospective study, we tried to mobilize patients early after free-flap transfer to the lower extremity by means of flow-through anastomosis for both arteries and veins. This study included 13 consecutive patients who underwent immediate free-flap transfer after wide resection of soft-tissue tumors of the lower extremity from March 2012 through July 2013. The defects were above the knee in 5 patients and below the knee in 8 patients. In all patients, flow-through anastomosis was used for both arteries and veins. The patients were mobilized starting on the first postoperative day, and their activities of daily life were gradually expanded, depending on the wound conditions. Postoperative complications and the progression of their activities of daily life were investigated retrospectively. No anastomotic failure or take back occurred. Partial flap necrosis occurred in 1 patient because of a poor perforator but was unrelated to early mobilization. All patients could move to wheelchairs on the first postoperative day. Within 1 week, 12 of 13 patients could start dangling and 10 of 13 patients could start ambulating. This study demonstrates that early mobilization after free-flap transfer to the lower extremity is made possible by flow-through anastomosis for both arteries and veins. Flow-through flaps have stable circulation from the acute phase and can tolerate early dangling and ambulation.

  19. Curling of flap tips in HIV-1 protease as a mechanism for substrate entry and tolerance of drug resistance.

    Science.gov (United States)

    Scott, W R; Schiffer, C A

    2000-12-15

    The human immunodeficiency virus type 1 (HIV-1) protease is an essential viral protein that is a major drug target in the fight against Acquired Immune Deficiency Syndrome (AIDS). Access to the active site of this homodimeric enzyme is gained when two large flaps, one from each monomer, open. The flap movements are therefore central to the function of the enzyme, yet determining how these flaps move at an atomic level has not been experimentally possible. In the present study, we observe the flaps of HIV-1 protease completely opening during a 10 ns solvated molecular dynamics simulation starting from the unliganded crystal structure. This movement is on the time scale observed by Nuclear Magnetic Resonance (NMR) relaxation data. The highly flexible tips of the flaps, with the sequence Gly-Gly-Ile-Gly-Gly, are seen curling back into the protein and thereby burying many hydrophobic residues. This curled-in conformational change has never been previously described. Previous models of this movement, with the flaps as rigid levers, are not consistent with the experimental data. The residues that participate in this hydrophobic cluster as a result of the conformational change are highly sensitive to mutation and often contribute to drug resistance when they do change. However, several of these residues are not part of the active site cavity, and their essential role in causing drug resistance could possibly be rationalized if this conformational change actually occurs. Trapping HIV-1 protease in this inactive conformation would provide a unique opportunity for future drug design.

  20. Dynamics of Micro-Air-Vehicle with Flapping Wings

    Directory of Open Access Journals (Sweden)

    K. Sibilski

    2004-01-01

    Full Text Available Small (approximately 6 inch long, or hand-held reconnaissance micro air vehicles (MAVs will fly inside buildings, and require hover for observation, and agility at low speeds to move in confined spaces. For this flight envelope insect-like flapping wings seem to be an optimal mode of flying. Investigation of the aerodynamics of flapping wing MAVs is very challenging. The problem involves complex unsteady, viscous flow (mainly laminar, with the moving wing generating vortices and interacting with them. At this early stage of research only a preliminary insight into the nature of the little known aerodynamics of MAVs has been obtained. This paper describes computational models for simulation of the controlled motion of a microelectromechanical flying insect – entomopter. The design of software simulation for entomopter flight (SSEF is presented. In particular, we will estimate the flight control algorithms and performance for a Micromechanical Flying Insect (MFI, a 80–100 mm (wingtip-to-wingtip device capable of sustained autonomous flight. The SSEF is an end-to-end tool composed of several modular blocks which model the wing aerodynamics and dynamics, the body dynamics, and in the future, the environment perception, control algorithms, the actuators dynamics, and the visual and inertial sensors. We present the current state of the art of its implementation, and preliminary results. 

  1. Ischemic flap survival improvement by composition-selective fat grafting with novel adipose tissue derived product - stromal vascular fraction gel.

    Science.gov (United States)

    Zhang, Pan; Feng, Jingwei; Liao, Yunjun; Cai, Junrong; Zhou, Tao; Sun, Mingliang; Gao, Jianhua; Gao, Kai

    2017-11-30

    Flap necrosis due to insufficient blood supply is a common postoperative complication in random pattern flaps. Stem cell therapies have emerged as promising biologics for tissue ischemia. A novel fat derived product, stromal vascular fraction gel (SVF-gel), can be prepared with lipoaspirate through simple mechanical processing, removing only the lipid content. SVF-gel enriches adipose-derived stem cells and potentially beneficial for flap necrosis. Nude mice ischemic flaps were treated with human SVF-gel, stromal vascular fraction (SVF) cell suspension or saline (n = 10). They were injected to the flap recipient beds, and necrosis and vascularization was assessed on postoperative day 14. We harvested the necrosis-free distal to evaluated skin healthiness and neovasculogenesis by Masson's trichrome stain and immunofluorescence, etc. Pro-angiogenic factors were assessed with tissue qRT-PCR. Finally, we traced the grafted human tissue with immunofluorescence. SVF-gel-treated flaps have the smallest necrotic zones (22.05% ± 0.0438) compared with the saline controls (53.78% ± 0.1412) or SVF-treated ones (35.54% ± 0.0850, p = 0.039). Numerous functional musculocutaneous perforators were developed around SVF-gel grafts. The SVF-gel-treated skin had the best fat restoration (231.3 ± 48.1 μm) among three groups (F = 10.83, p = 0.0102) while saline-treated flap distal appeared fibrotic. SVF-gel-treated flaps also had ∼43% more CD31 + capillaries (p = 0.0152) with ∼3 folds more gene expression of angiogenic cytokines of VEGF and bFGF (p = 0.0310 and 0.0303, respectively) than saline-treated controls. Furthermore, we found hSVF-gel cells (hGolgi+) had directly engrafted as vessel component (α-smooth muscle actin, α-SMA+) to the flap. Adipose cellular matrix enhanced flap neovascularization partly by direct incorporation, improved flap survival and fat restoration. The composition-selective fat grafting with SVF-gel demonstrated efficacy

  2. Towards Efficient Fluid-Structure-Control Interaction for Smart Rotors

    NARCIS (Netherlands)

    Gillebaart, T.

    2016-01-01

    One of the solutions to speed up the energy transition is the smart rotor concept: wind turbine blades with actively controlled Trailing Edge Flaps. In the past decade feasibility studies (both numerical and experimental) have been performed to assess the applicability of smart rotors in future

  3. Fascia-only anterolateral thigh flap for extremity reconstruction.

    Science.gov (United States)

    Fox, Paige; Endress, Ryan; Sen, Subhro; Chang, James

    2014-05-01

    The ability to use the anterolateral thigh (ALT) flap as a vascularized fascial flap, without skin or muscle, was first documented by Koshima et al in 1989. The authors mention the possibility of using the fascia alone for dural reconstruction. Despite its description more than 20 years ago, little literature exists on the application of the ALT flap as a vascularized fascial flap. In our experience, the ALT flap can be used as a fascia-only flap for thin, pliable coverage in extremity reconstruction. After approval from the institutional review board, the medical records and photographs of patients who had undergone fascia-only ALT free flaps for extremity reconstruction were reviewed. Photographic images of patients were then matched to patients who had undergone either a muscle-only or a fasciocutaneous free flap reconstruction of an extremity. Photographs of the final reconstruction were then given to medical and nonmedical personnel for analysis, focusing on aesthetics including color and contour. Review of cases performed over a 2-year period demonstrated similar ease of harvest for fascia-only ALT flaps compared to standard fasciocutaneous ALT flaps. Fascia-only flaps were used for thin, pliable coverage in the upper and lower extremities. There was no need for secondary procedures for debulking or aesthetic flap revision. In contrast to muscle flaps, which require muscle atrophy over time to achieve their final appearance, there was a similar flap contour from approximately 1 month postoperatively throughout the duration of follow-up. When a large flap is required, the fascia-only ALT has the advantage of a single-line donor-site scar. Photograph comparison to muscle flaps with skin grafts and fasciocutaneous flaps demonstrated improved color, contour, and overall aesthetic appearance of the fascia-only ALT over muscle and fasciocutaneous flaps. The fascia-only ALT flap provides reliable, thin, and pliable coverage with improved contour and color over

  4. Active Shielding and Control of Environmental Noise

    Science.gov (United States)

    Tsynkov, S. V.

    2001-01-01

    In the framework of the research project supported by NASA under grant # NAG-1-01064, we have studied the mathematical aspects of the problem of active control of sound, i.e., time-harmonic acoustic disturbances. The foundations of the methodology are described in our paper [1]. Unlike. many other existing techniques, the approach of [1] provides for the exact volumetric cancellation of the unwanted noise on a given predetermined region airspace, while leaving unaltered those components of the total acoustic field that are deemed as friendly. The key finding of the work is that for eliminating the unwanted component of the acoustic field in a given area, one needs to know relatively little; in particular, neither the locations nor structure nor strength of the exterior noise sources need to be known. Likewise, there is no need to know the volumetric properties of the supporting medium across which the acoustic signals propagate, except, maybe, in a narrow area of space near the perimeter of the protected region. The controls are built based solely on the measurements performed on the perimeter of the domain to be shielded; moreover, the controls themselves (i.e., additional sources) are concentrated also only on or near this perimeter. Perhaps as important, the measured quantities can refer to the total acoustic field rather than to its unwanted component only, and the methodology can automatically distinguish between the two. In [1], we have constructed the general solution for controls. The apparatus used for deriving this general solution is closely connected to the concepts of generalized potentials and boundary projections of Calderon's type. For a given total wave field, the application of a Calderon's projection allows one to definitively tell between its incoming and outgoing components with respect to a particular domain of interest, which may have arbitrary shape. Then, the controls are designed so that they suppress the incoming component for the domain

  5. Flap testing on the rotating test rig in the INDUFLAP project

    DEFF Research Database (Denmark)

    Barlas, Athanasios; Aagaard Madsen, Helge; Enevoldsen, Karen

    Tests of a prototype Controllable Rubber Trailing Edge Flap (CRTEF) are performed on the rotating test rig at the Risø campus of DTU. The general description and objectives are presented, along with an overview of sensors on the setup and the test cases. The post-processing of data is discussed...

  6. Monitoring and controlling ovarian activity in elephants.

    Science.gov (United States)

    Thitaram, Chatchote; Brown, Janine L

    2017-12-13

    Both Asian (Elephas maximus) and African (Loxodonta africana) elephants are important keystone, umbrella and flagship species. Paradoxically, world population numbers of both species are declining in many of their natural ranges due mainly to poaching, while over population of elephants in some areas is resulting in serious human-elephant conflict, and modifications of natural habitats that impact biodiversity. Understanding mechanisms of reproductive control is vital to effective population management, and for that reason significant advances have been made in endocrine and ultrasonographic monitoring techniques, particularly in studies of elephants ex situ. However, there remains a need to develop new methods to control ovarian activity, both for enhancing and inhibiting reproduction, to maintain population numbers at levels that ensure species survival and their ability to safely cohabitate with humans and other species. We present an overview of reproductive monitoring methods and how they have contributed to our knowledge of elephant reproductive biology, as well as their application for in situ and ex situ conservation purposes. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Development of Variable Camber Continuous Trailing Edge Flap for Performance Adaptive Aeroelastic Wing

    Science.gov (United States)

    Nguyen, Nhan; Kaul, Upender; Lebofsky, Sonia; Ting, Eric; Chaparro, Daniel; Urnes, James

    2015-01-01

    This paper summarizes the recent development of an adaptive aeroelastic wing shaping control technology called variable camber continuous trailing edge flap (VCCTEF). As wing flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. The initial VCCTEF concept was developed in 2010 by NASA under a NASA Innovation Fund study entitled "Elastically Shaped Future Air Vehicle Concept," which showed that highly flexible wing aerodynamic surfaces can be elastically shaped in-flight by active control of wing twist and bending deflection in order to optimize the spanwise lift distribution for drag reduction. A collaboration between NASA and Boeing Research & Technology was subsequently funded by NASA from 2012 to 2014 to further develop the VCCTEF concept. This paper summarizes some of the key research areas conducted by NASA during the collaboration with Boeing Research and Technology. These research areas include VCCTEF design concepts, aerodynamic analysis of VCCTEF camber shapes, aerodynamic optimization of lift distribution for drag minimization, wind tunnel test results for cruise and high-lift configurations, flutter analysis and suppression control of flexible wing aircraft, and multi-objective flight control for adaptive aeroelastic wing shaping control.

  8. An aerodynamic model for insect flapping wings in forward flight.

    Science.gov (United States)

    Han, Jong-Seob; Chang, Jo Won; Han, Jae-Hung

    2017-03-31

    This paper proposes a semi-empirical quasi-steady aerodynamic model of a flapping wing in forward flight. A total of 147 individual cases, which consisted of advance ratios J of 0 (hovering), 0.125, 0.25, 0.5, 0.75, 1 and  ∞, and angles of attack α of  -5 to 95° at intervals of 5°, were examined to extract the aerodynamic coefficients. The Polhamus leading-edge suction analogy and power functions were then employed to establish the aerodynamic model. In order to preserve the existing level of simplicity, K P and K V , the correction factors of the potential and vortex force models, were rebuilt as functions of J and α. The estimations were nearly identical to direct force/moment measurements which were obtained from both artificial and practical wingbeat motions of a hawkmoth. The model effectively compensated for the influences of J, particularly showing outstanding moment estimation capabilities. With this model, we found that using a lower value of α during the downstroke would be an effective strategy for generating adequate lift in forward flight. The rotational force and moment components had noticeable portions generating both thrust and counteract pitching moment during pronation. In the upstroke phase, the added mass component played a major role in generating thrust in forward flight. The proposed model would be useful for a better understanding of flight stability, control, and the dynamic characteristics of flapping wing flyers, and for designing flapping-wing micro air vehicles.

  9. Breast reconstruction by pedicled transverse rectus abdominis myocutaneous flap

    Directory of Open Access Journals (Sweden)

    Kozarski Jefta

    2004-01-01

    Full Text Available Reconstruction of the amputated breast in female patients after surgical management of breast carcinoma is possible with the use of autologous tissue, synthetic implants, or by combining autologous tissue and synthetic materials. Autologous tissue provides soft and sufficiently elastic tissue which is usable for breast reconstruction and eventually obtains original characteristics of the surrounding tissue on the chest wall. The use of the TRAM flap for breast reconstruction was introduced in 1982 by Hartrampf Scheflan, and Black. The amount of the TRAM flap tissue allows breast reconstruction in the shape most adequate to the remaining breast. The possibilities of using the TRAM flap as pedicled myocutaneous flap or as free TRAM flap make this flap a superior choice for breast reconstruction in comparison with other flaps.

  10. Prevention of hair growth in myocutaneous flap reconstruction.

    Science.gov (United States)

    Eliachar, I; Kraus, D H; Bergfeld, W F; Tucker, H M

    1990-08-01

    Myocutaneous flaps play a prominent role in the immediate reconstruction of surgical defects following ablative oncologic procedures in the head and neck. Transfer of hair-bearing skin into the reconstructed upper digestive tract can be a major disadvantage associated with the pectoralis major flap. De-epithelialization of skin to the dermal level, removing the majority of skin appendages, can convert a myocutaneous flap to a "myodermal" flap. Platysma myocutaneous and myodermal flaps were grafted into the oral cavity of 13 dogs. Gross and histologic evaluation confirmed decreased hair growth in the experimental myodermal flap. Wound complications and graft survival were similar for both techniques. Diminished hair growth further supports the utility of myodermal flaps in hairy male patients undergoing upper digestive tract reconstruction.

  11. BATMAV: a 2-DOF bio-inspired flapping flight platform

    Science.gov (United States)

    Bunget, Gheorghe; Seelecke, Stefan

    2010-04-01

    Due to the availability of small sensors, Micro-Aerial Vehicles (MAVs) can be used for detection missions of biological, chemical and nuclear agents. Traditionally these devices used fixed or rotary wings, actuated with electric DC motortransmission, a system which brings the disadvantage of a heavier platform. The overall objective of the BATMAV project is to develop a biologically inspired bat-like MAV with flexible and foldable wings for flapping flight. This paper presents a flight platform that features bat-inspired wings which are able to actively fold their elbow joints. A previous analysis of the flight physics for small birds, bats and large insects, revealed that the mammalian flight anatomy represents a suitable flight platform that can be actuated efficiently using Shape Memory Alloy (SMA) artificial-muscles. A previous study of the flight styles in bats based on the data collected by Norberg [1] helped to identify the required joint angles as relevant degrees of freedom for wing actuation. Using the engineering theory of robotic manipulators, engineering kinematic models of wings with 2 and 3-DOFs were designed to mimic the wing trajectories of the natural flier Plecotus auritus. Solid models of the bat-like skeleton were designed based on the linear and angular dimensions resulted from the kinematic models. This structure of the flight platform was fabricated using rapid prototyping technologies and assembled to form a desktop prototype with 2-DOFs wings. Preliminary flapping test showed suitable trajectories for wrist and wingtip that mimic the flapping cycle of the natural flyer.

  12. To flap or not to flap: a discussion between a fish and a jellyfish

    Science.gov (United States)

    Martin, Nathan; Roh, Chris; Idrees, Suhail; Gharib, Morteza

    2016-11-01

    Fish and jellyfish are known to swim by flapping and by periodically contracting respectively, but which is the more effective propulsion mechanism? In an attempt to answer this question, an experimental comparison is made between simplified versions of these motions to determine which generates the greatest thrust for the least power. The flapping motion is approximated by pitching plates while periodic contractions are approximated by clapping plates. A machine is constructed to operate in either a flapping or a clapping mode between Reynolds numbers 1,880 and 11,260 based on the average plate tip velocity and span. The effect of the total sweep angle, total sweep time, plate flexibility, and duty cycle are investigated. The average thrust generated and power required per cycle are compared between the two modes when their total sweep angle and total sweep time are identical. In general, operating in the clapping mode required significantly more power to generate a similar thrust compared to the flapping mode. However, modifying the duty cycle for clapping caused the effectiveness to approach that of flapping with an unmodified duty cycle. These results suggest that flapping is the more effective propulsion mechanism within the range of Reynolds numbers tested. This work was supported by the Charyk Bio-inspired Laboratory at the California Institute of Technology, the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144469, and the Summer Undergraduate Research Fellowships program.

  13. The vastus intermedius periosteal (VIP) flap: a novel flap for osteoinduction.

    Science.gov (United States)

    Maercks, Rian Adam; Runyan, Christopher Michael; Jones, Donna Carlson; Taylor, Jesse Adam

    2010-07-01

    Periosteum's role in fracture healing is widely recognized, and its function in bone tissue engineering shows great potential. Here we introduce a novel periosteal free flap to be used as an abundant source of periosteum in the engineering and repair of bone. The descending branch of the lateral femoral circumflex vessels were isolated on 11 fresh human cadavers, preserving perforators to the vastus intermedius muscle. A cuff of vastus intermedius and approximately 75% of the circumference of the femoral periosteum were harvested from 6 cm proximal to the knee to 8 cm distal to the greater trochanter. Flap pedicle length and periosteal dimensions were measured. The pedicle arteries were injected with radiopaque dye, and radiographs were taken. A musculoperiosteal flap was elevated with visible descending perforators in each case. Mean flap surface area was 128 cm(2) (+/-99-143 cm(2)). Average pedicle length was 8 cm (+/-6-11 cm). Dye injection confirmed that the flaps blood supply was the descending branch of the lateral femoral circumflex artery. This anatomical study confirms the vascular supply of this large musculoperiosteal flap. Future work will test its efficacy as an osteoinductive agent in bone repair and tissue engineering in humans. Thieme Medical Publishers.

  14. Flapping micro plane watches where it goes

    NARCIS (Netherlands)

    de Wagter, C.; Lentink, D.; Mols, B.

    2005-01-01

    In a time span of only ten weeks, a team of eleven highly dedicated students have managed to design a unique flapping miniature aircraft, named DelFly. The aircraft can hover almost motionless in one spot and fly at considerable speed as well while being more stable and less vulnerable than a

  15. Regional skin flaps in partial laryngectomy.

    Science.gov (United States)

    Conley, J

    1975-06-01

    The use of regional neck flaps for rehabilitation has permitted an extension of operations on the glottis. The resection may include both vocal cords, both ventricular bands, one arytenoid and slight subglottic extension in a one- or two-stage technique. The resultant voice is low pitched, soft and has limited range. The cure rate was 85 percent.

  16. Clinical application of free omental flap transfer

    Energy Technology Data Exchange (ETDEWEB)

    Harii, K.

    1978-04-01

    In the field of reconstruction surgery, the greater omentum has been used as a transposed flap for the treatment of chronic lymphedema, radionecrosis, and so forth. Its transferable range was limited by the length of its pedicle. Microvascular anastomosis allows for free transplantation of this organ and has vastly expanded its usefulness.

  17. Oral cavity reconstruction with the masseter flap

    NARCIS (Netherlands)

    Mahieu, R.; Russo, S.; Gualtieri, T.; Colletti, G.; Deganello, A.

    The purpose of this report is to highlight how an unusual, outdated, unpopular and overlooked reconstructive method such as the masseter flap can be a reliable, straightforward and effective solution for oral reconstruction in selected cases. We report the transposition of the masseter crossover

  18. Flapping wing aerodynamics: from insects to vertebrates.

    Science.gov (United States)

    Chin, Diana D; Lentink, David

    2016-04-01

    More than a million insects and approximately 11,000 vertebrates utilize flapping wings to fly. However, flapping flight has only been studied in a few of these species, so many challenges remain in understanding this form of locomotion. Five key aerodynamic mechanisms have been identified for insect flight. Among these is the leading edge vortex, which is a convergent solution to avoid stall for insects, bats and birds. The roles of the other mechanisms - added mass, clap and fling, rotational circulation and wing-wake interactions - have not yet been thoroughly studied in the context of vertebrate flight. Further challenges to understanding bat and bird flight are posed by the complex, dynamic wing morphologies of these species and the more turbulent airflow generated by their wings compared with that observed during insect flight. Nevertheless, three dimensionless numbers that combine key flow, morphological and kinematic parameters - the Reynolds number, Rossby number and advance ratio - govern flapping wing aerodynamics for both insects and vertebrates. These numbers can thus be used to organize an integrative framework for studying and comparing animal flapping flight. Here, we provide a roadmap for developing such a framework, highlighting the aerodynamic mechanisms that remain to be quantified and compared across species. Ultimately, incorporating complex flight maneuvers, environmental effects and developmental stages into this framework will also be essential to advancing our understanding of the biomechanics, movement ecology and evolution of animal flight. © 2016. Published by The Company of Biologists Ltd.

  19. Intraoperative Hemifacial Composite Flap Perfusion Assessment Using Spatial Frequency Domain Imaging: A Pilot Study in Preparation for Facial Transplantation.

    Science.gov (United States)

    Vargas, Christina R; Nguyen, John T; Ashitate, Yoshitomo; Angelo, Joseph; Venugopal, Vivek; Kettenring, Frank; Neacsu, Florin; Frangioni, John V; Gioux, Sylvain; Lee, Bernard T

    2016-02-01

    Vascularized composite allotransplantation represents an important advancement in the field of reconstructive microsurgery and has continued to increase in popularity. The significant clinical morbidity associated with flap failure represents an important barrier to even more widespread use of these techniques. Early identification of vascular compromise has been associated with a higher salvage rate, yet most surgeons rely only on clinical assessment intraoperatively. Spatial frequency domain imaging (SFDI) presents a noncontact, objective measurement of tissue oxygenation over a large field of view. This study aims to evaluate the use of SFDI technology in hemifacial composite flap compromise as could occur during facial transplant. Six composite hemifacial flaps were created in three 35-kg Yorkshire pigs and continuously imaged using SFDI before, during, and after 15-minute selective vascular pedicle occlusion. Arterial and venous clamping trials were performed for each flap. Changes in oxyhemoglobin concentration, deoxyhemoglobin concentration, and total hemoglobin were quantified over time. The SFDI successfully measured changes in oxygenation parameters in all 6 composite tissue flaps. Significant changes in oxyhemoglobin, deoxyhemoglobin, and total hemoglobin were seen relative to controls. Early and distinct patterns of alteration were noted in arterial and in venous compromise relative to one another. The need for noninvasive, reliable assessment of composite tissue graft viability is apparent, given the morbidity associated with flap failure. The results of this study suggest that SFDI technology shows promise in providing intraoperative guidance with regard to pedicle vessel integrity during reconstructive microsurgery.

  20. Impact of cigarette smoking on clinical outcomes of periodontal flap surgical procedures: a systematic review and meta-analysis.

    Science.gov (United States)

    Kotsakis, Georgios A; Javed, Fawad; Hinrichs, James E; Karoussis, Ioannis K; Romanos, Georgios E

    2015-02-01

    Periodontal flap surgery is frequently used to remove subgingival deposits, yielding consequential reductions in gingival inflammation and probing depth (PD) with a gain in clinical attachment level (CAL) to treat advanced periodontal disease. However, clinical studies have reported diminished periodontal healing in smokers compared with non-smokers. The aim of the present systematic review and meta-analysis was to assess the impact of cigarette smoking on clinical outcomes following periodontal flap surgical procedures. A systematic electronic review of articles relevant to periodontal flap surgical procedures in smokers was conducted from 1977 to March 2014 inclusive, using predefined, optimized search strategies. Meta-analyses were done separately for changes in the two primary outcomes of PD and CAL. The initial search yielded 390 titles and abstracts. After screening, eight controlled clinical studies were finally selected. Three studies were assessed as having a low risk of bias, two as having moderate risk of bias, and three as having a high risk of bias. Qualitative assessment of the articles consistently showed an improved treatment effect among non-smokers versus smokers. The reduction in PD in smokers and non-smokers ranged from 0.76 to 2.05 mm and 1.27 to 2.40 mm, respectively. For CAL, the gain in non-smokers versus smokers ranged from 0.29 to 1.6 mm and 0.09 to 1.2 mm, respectively. Meta-analysis on eight studies reporting on 363 study participants demonstrated an increased reduction in mean (95% confidence interval) PD of 0.39 (0.33 to 0.45) mm. Similar results were found for mean gain in CAL (0.35 [0.30 to 0.40] mm, n = 4 studies). Considering the relatively homogenous information available, the authors conclude that active smokers could be candidates for periodontal flap surgical procedures. However, the magnitude of the therapeutic effect is compromised in smokers compared with non-smokers. Therefore, cigarette smokers should be: 1) encouraged to

  1. Development of a generic activities model of command and control

    OpenAIRE

    Stanton, NA; Baber, C; Walker, GH; Houghton, RJ; McMaster, R; Stewart, R.; D.; Harris; Jenkins, DP; Young, MS; Salmon, PM

    2008-01-01

    This paper reports on five different models of command and control. Four different models are reviewed: a process model, a contextual control model, a decision ladder model and a functional model. Further to this, command and control activities are analysed in three distinct domains: armed forces, emergency services and civilian services. From this analysis, taxonomies of command and control activities are developed that give rise to an activities model of command and control. This model w...

  2. Corneal flap thickness and topography changes induced by flap creation during laser in situ keratomileusis.

    Science.gov (United States)

    Güell, José L; Velasco, Fortino; Roberts, Cynthia; Sisquella, Maria Teresa; Mahmoud, Ashraf

    2005-01-01

    To determine the corneal flap thickness profile produced by 3 microkeratomes and the topographic changes induced by flap creation in laser in situ keratomileusis (LASIK). Cornea and Refractive Surgery Unit, Instituto de Microcirugia Ocular de Barcelona, Autonoma University, Barcelona, Spain. In this prospective consecutive nonrandomized comparative study, patients were divided into 2 groups. In Group 1 (75 eyes), 3 microkeratomes were used: Moria LSX One, Moria M2, and Amadeus (AMO); 25 eyes per microkeratome. Pachymetry was measured with a DGH pachymeter in the center of the cornea and 3.0 mm from the center at 4 cardinal points (superior, inferior, nasal, and temporal; 3 measurements at each point) before and after the cut. The flap thickness in each sector was calculated by subtracting the mean post-flap corneal thickness from the mean pre-flap corneal thickness. In Group 2 (33 eyes), the M2 microkeratome with a 130 microm plate was used to create a superotemporal hinged flap (9 eyes) or a superonasal hinged flap (24 eyes). The topographic change induced by the microkeratome cut was evaluated using 4 sequential data acquisitions by the Keratron Scout topographic unit (Optikon) before and immediately after the cut (before laser ablation). Cardinal and oblique astigmatism and change in the axis were calculated by vectorial analysis of the simulated keratometry. Topographic Zernike analysis was performed in a subgroup. With the LSX One microkeratome, the mean flap thickness was 151.7 microm centrally, 161.9 microm superiorly, 151.4 microm inferiorly, 156.1 microm temporally, and 167.5 microm nasally. There was no statistically significant difference between the areas studied (P.05). With the Amadeus microkeratome, the mean flap thickness was 140.0 microm centrally, 152.5 superiorly, 128.5 microm inferiorly, 145.0 microm temporally, and 147.0 microm nasally. Statistically significant differences (P>.05) were found in the 4 sectors of the flap. With vectorial

  3. A comparison of two implant techniques on patient-based outcome measures: a report of flapless vs. conventional flapped implant placement

    NARCIS (Netherlands)

    Lindeboom, Jerome A.; van Wijk, Arjen J.

    2010-01-01

    Background Flapless implant surgery is considered to offer advantages over the traditional flap access approach. There may be minimized bleeding, decreased surgical times and minimal patient discomfort. Controlled studies comparing patient outcome variables to support these assumptions, however, are

  4. A comparison of two implant techniques on patient-based outcome measures: a report of flapless vs. conventional flapped implant placement

    NARCIS (Netherlands)

    Lindeboom, J.A.; van Wijk, A.J.

    2010-01-01

    Background: Flapless implant surgery is considered to offer advantages over the traditional flap access approach. There may be minimized bleeding, decreased surgical times and minimal patient discomfort. Controlled studies comparing patient outcome variables to support these assumptions, however,

  5. Aerodynamic Control using Distributed Active Bleed

    Science.gov (United States)

    Kearney, John; Glezer, Ari

    2015-11-01

    The global aerodynamic loads on a stationary and pitching airfoil at angles of attack beyond the static and dynamic stall margins, respectively are controlled in wind tunnel experiments using regulated distributed bleed driven by surface pressure differences. High-speed PIV and proper orthogonal decomposition of the vorticity flux on the static airfoil show that the bleed engenders trains of discrete vortices that advect along the surface and are associated with a local instability that is manifested by a time-averaged bifurcation of the vorticity layer near the bleed outlets and alters the vorticity flux over the airfoil and thereby the aerodynamic loads. Active bleed is used on a dynamically pitching airfoil (at reduced frequencies up to k = 0.42) to modulate the evolution of vorticity concentrations during dynamic stall. Time-periodic bleed improved the pitch stability by reducing adverse pitching moment (``negative damping'') that can precipitate structural instabilities. At the same time, the maintains the cycle-average loads to within 5% of the base flow levels by segmenting the vorticity layer during upstroke and promoting early flow attachment during downstroke segments of the pitch cycle. Supported by Georgia Tech VLRCOE.

  6. Reverse-Flow Lateral Tarsal Island Flap for Covering the Great Toe Donor Site of Wraparound Flap.

    Science.gov (United States)

    Jia, Yachao; Xu, Jia; Kang, Qinglin; Zhang, Changqing; Chai, Yimin

    2016-10-01

    Coverage of the great toe donor site of wraparound flap remains a challenge. This report presents the results of using an innervated pedicled reverse-flow lateral tarsal island flap for covering the great toe donor site of wraparound flap. Between 2005 and 2010, 11 reverse-flow lateral tarsal island flaps were used to cover the great toe donor site of wraparound flap in 11 patients. This pedicled flap designed on the lateral tarsal area of foot was based distally on the dorsalis pedis artery; the lateral dorsal pedal cutaneous nerve was incorporated into the reverse-flow lateral tarsal island flap and coapted with the first plantar digital nerve. The donor sites of reverse-flow lateral tarsal island flap were covered with inguinal full-thickness skin grafts. All flaps achieved primary healing except for two that suffered from mild venous insufficiency which was managed by conservative intervention. All skin grafts covering the donor site of reverse-flow lateral tarsal island flap healed uneventfully. The mean follow-up was 24 months (range, 18-48 months). The mean hallux metatarsophalangeal-interphalangeal scale score was 92 points (range, 85-97 points) at 6 months postoperatively. The static 2-point discrimination of the reverse-flow lateral tarsal island flap ranged from 6 to 14 mm (mean 10 mm). None of the patients were restricted in standing or walking during follow-up. The reverse-flow lateral tarsal island flap based distally on the dorsalis pedis artery has a constant pedicle that is sufficiently long. This innervated pedicle flap is a reliable option to cover the great toe donor site of wraparound flap with satisfactory functional and cosmetic results and acceptable donor site morbidity.

  7. Wing loading on a 60 degree delta wing with vortex flaps

    Science.gov (United States)

    Marchman, J. F., III; Donatelli, D. A.; Terry, J. E.

    1983-01-01

    Wind tunnel tests were conducted on a 60 deg delta wing with three vortex flap designs to determine pressure distributions over the wing and flap. The results showed that an optimum vortex flap design depends on proper definition of the vortex flap deflection angle. They also revealed that flap thickness plays an important role in the behavior of the vortex flow over the flap and wing and can have a substantial effect on wing and flap pressure loading. Design codes which fail to account for thickness may result in a much less than optimum flap and deprive the designer of an important tool in designing an effective flap with optimum loading.

  8. Expression microarray identifies novel markers of free flap failure in a rat model.

    Science.gov (United States)

    Mithani, Suhail K; Bluebond-Langner, Rachel; Rodriguez, Eduardo D

    2009-09-01

    Clinical detection of free flap failure lacks sensitivity. Failure is likely accompanied by altered gene expression; however, a genomic approach that identifies potential biomarkers and therapeutic targets has not been described. This study identifies genetic RNA expression alterations via microarray in a free flap failure animal model. A free tissue transfer rat model based on the inferior epigastric vessels was utilized. After microscopic anastomosis, the vein was occluded and RNA extracted from flap tissue of failure and control groups. Gene expression of 3 experimental and control group samples was assessed with the Affymetrix GeneChip Rat 230 v2.0 microarray. Quantitative reverse transcription polymerase chain reaction was performed on RNA of genes identified on an additional 6 experimental and 7 control group flaps. Eight hundred ninety of 28,000 genes had greater than 2-fold expression differences between experimental and controls. Student t test and 2-way analysis of variance filtering with equal variance identified 53 genes with statistically significant differences. Hierarchical clustering by gene ontology identified 4 genes with likely involvement in failure pathogenesis: RT1 class II, locus Bb, secreted frizzled-related protein 1, platelet/endothelial cell adhesion molecule, and Claudin 5. Validation performed by quantitative reverse transcription polymerase chain reaction revealed statistically significant expression alterations in locus Bb, platelet/endothelial cell adhesion molecule, and Claudin 5 of the failure group. Utilizing expression thresholds for test positivity, venous occlusion was predicted with 100% sensitivity and 86% specificity. Three highly sensitive and specific novel genes predictive of flap failure from venous occlusion were identified with altered expression in an animal model.

  9. Periodontal wound healing with and without platelet-rich plasma: histologic observations and assessment of flap tensile strength.

    Science.gov (United States)

    Powell, Charles A; Bannister, Sharon R; Mackey, Scott A; Maller, Steven C; McDonnell, Howard T; Deas, David E

    2009-06-01

    Platelet-rich plasma (PRP) has been promoted as a surgical adjunct to enhance hard and soft tissue wound healing. Although anecdotally reported to be of value, the results of controlled studies examining the added effects of PRP on surgical procedures have been mixed. The purpose of this study was to test the effect of PRP on flap strength at various post-surgical time points in a minipig animal model. Twelve Yucatan minipigs provided four sites per animal. PRP was prepared from each animal at the time of surgery. Following reflection of a mucoperiosteal flap in each quadrant, subgingival plaque and calculus were removed. Each surgical site was irrigated with sterile saline; prior to suturing, one randomly selected test quadrant in each arch was treated with PRP. Four animals were euthanized at day 14, and two animals were euthanized at 2, 7, 10, and 28 days. The flap strength in each quadrant was tested by attaching to a loop of 3-0 silk suture through the tissue; the force required to separate the flap from the tooth/bone interface was recorded for each site. A separate portion of each flap site was prepared for descriptive histologic examination, including inflammation, hemorrhage, and new bone growth. Flap strength was significantly less on day 2 compared to later time points, and there were no significant differences between the test and control groups. No histologic differences in healing between test and control sites were seen at any time point. PRP did not seem to contribute to greater flap strength at any post-surgical time point, nor was it associated with any histologic differences in wound healing in this Yucatan minipig model. The time points chosen for observation post-surgery, as well as the variability in the PRP platelet count, may have contributed to the lack of positive findings in this study.

  10. Comparison of crestal bone loss around dental implants placed in healed sites using flapped and flapless techniques: a systematic review.

    Science.gov (United States)

    Vohra, Fahim; Al-Kheraif, Abdulaziz A; Almas, Khalid; Javed, Fawad

    2015-02-01

    The aim of the present systematic review is to compare the crestal bone loss (CBL) around dental implants placed in healed sites using flapped and flapless surgical techniques. The focused question was, "Does flapped and flapless surgical technique influence CBL around dental implants placed in healed sites?" Databases were searched from 1975 up to and including May 2014 using different combinations of the following keywords: "crestal bone loss"; "dental implant"; "surgery"; "flap"; and "flapless." Unpublished data, experimental studies, letters to the editor, review articles, case reports, commentaries, and articles published in languages other than English were excluded. In all studies, the test group comprised implants placed using flapless surgery, and the control group, implants placed after reflection of a full-thickness mucoperiosteal flap. Ten clinical studies were included. In five studies, CBL around implants was comparable between the test and control groups. In four studies, implants in the test group showed significantly less CBL compared with the control group. In one study, CBL was significantly higher in the test group than the control group. CBL around dental implants placed in healed sites using flapped and flapless techniques is comparable.

  11. Lateral thoracic artery axial pattern flap in cats.

    Science.gov (United States)

    Benzioni, Hadas; Shahar, Ron; Yudelevich, Sigal; Shipov, Anna; Milgram, Joshua

    2009-01-01

    To describe the location of the lateral thoracic artery (LTA), determine dimensions of an axial pattern flap based on this artery, and report use of this flap in 2 cats. Ex vivo study and case reports. Cat cadavers (n=8); cats (n=2) with thoracic limb skin defects. Dissection of the LTA was carried out on 1 side of each cadaver and the contralateral side was used for injection studies. In 4 specimens, the LTA was cannulated and injected with positive contrast material and the flap was raised and radiographed. In 4 specimens, the flap was injected with methylene blue. Adequacy of flap injection was subjectively evaluated and leakage of methylene blue from the cut edge was noted. The cutaneous location of the LTA caudal to the triceps muscle was confirmed. Mean flap size was 8.7 cm x 15.5 cm for a mature, average-sized cat. Perfusion of the entire flap was demonstrated and viability of the flap was confirmed in 2 clinical cases. The LTA flap is useful for repair of skin defects of the brachium and antebrachium in cats. The LTA flap is an alternative technique for repair of skin defects involving the thoracic limb of cats.

  12. Active Vibration Control of a Flexible Structure Using Piezoceramic Actuators

    Directory of Open Access Journals (Sweden)

    J. Fei

    2008-03-01

    Full Text Available Considerable attention has been devoted recently to active vibration control using intelligent materials as actuators. This paper presents results on active control schemes for vibration suppression of flexible steel cantilever beam with bonded piezoelectric actuators. The PZT patches are surface bonded near the fixed end of flexible steel cantilever beam. The dynamic model of the flexible steel cantilever beam is derived. Active vibration control methods, strain rate feedback control (SRF, positive position feedback control (PPF are investigated and implemented using xPC Target real-time system. Experimental results demonstrate that the SRF control and PPF control achieve effective vibration suppression results of steel cantilever beam.

  13. Active controllers and the time duration to learn a task

    Science.gov (United States)

    Repperger, D. W.; Goodyear, C.

    1986-01-01

    An active controller was used to help train naive subjects involved in a compensatory tracking task. The controller is called active in this context because it moves the subject's hand in a direction to improve tracking. It is of interest here to question whether the active controller helps the subject to learn a task more rapidly than the passive controller. Six subjects, inexperienced to compensatory tracking, were run to asymptote root mean square error tracking levels with an active controller or a passive controller. The time required to learn the task was defined several different ways. The results of the different measures of learning were examined across pools of subjects and across controllers using statistical tests. The comparison between the active controller and the passive controller as to their ability to accelerate the learning process as well as reduce levels of asymptotic tracking error is reported here.

  14. Management Control of Public and Not-for-Profit Activities

    OpenAIRE

    Hofstede, G.

    1981-01-01

    Traditional approaches to management control usually fail for public and not-for-profit activities. The type of control applicable to such activities depends on four criteria: are objectives unambiguous, outputs measurable, effects of interventions known, and is the activity repetitive? Depending on where activities stand with regard to these criteria, the control applicable corresponds to one of six different types: routine, expert, trial-and-error, intuitive, judgemental, or political contr...

  15. Low Activity Waste Feed Process Control Strategy

    Energy Technology Data Exchange (ETDEWEB)

    STAEHR, T.W.

    2000-06-14

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system.

  16. Use of the Anterolateral Thigh and Vertical Rectus Abdominis Musculocutaneous Flaps as Utility Flaps in Reconstructing Large Groin Defects

    Directory of Open Access Journals (Sweden)

    Edwin Jonathan Aslim

    2014-09-01

    Full Text Available BackgroundGroin dissections result in large wounds with exposed femoral vessels requiring soft tissue coverage, and the reconstructive options are diverse. In this study we reviewed our experience with the use of the pedicled anterolateral thigh and vertical rectus abdominis musculocutaneous flaps in the reconstruction of large groin wounds.MethodsGroin reconstructions performed over a period of 10 years were evaluated, with a mean follow up of two years. We included all cases with large or complex (involving perineum defects, which were reconstructed with the pedicled anterolateral thigh musculocutaneous or the vertical rectus abdominis musculocutaneous (VRAM flaps. Smaller wounds which were covered with skin grafts, locally based flaps and pedicled muscle flaps were excluded.ResultsTwenty-three reconstructions were performed for large or complex groin defects, utilising the anterolateral thigh (n=10 and the vertical rectus abdominis (n=13 pedicled musculocutaneous flaps. Femoral vein reconstruction with a prosthetic graft was required in one patient, and a combination flap (VRAM and gracilis muscle flap was performed in another. Satisfactory coverage was achieved in all cases without major complications. No free flaps were used in our series.ConclusionsThe anterolateral thigh and vertical rectus abdominis pedicled musculocutaneous flaps yielded consistent results with little morbidity in the reconstruction of large and complex groin defects. A combination of flaps can be used in cases requiring extensive cover.

  17. The radial artery superficial palmar branch flap: a modified free thenar flap with constant innervation.

    Science.gov (United States)

    Yang, Jae-Won; Kim, Jin-Soo; Lee, Dong-Chul; Ki, Sae-Hwi; Roh, Si-Young; Abdullah, Shalimar; Tien, Huey-Yuan

    2010-10-01

    The free thenar flap is useful for coverage of volar finger defects but has an inconstant innervation based on the presence of either the lateral antebrachial cutaneous nerve (LABC) or the superficial sensory branch of the radial nerve (SSRN). A detailed anatomic study on 30 adult fresh frozen cadavers preinjected with silicone rubber compound to demarcate arterial anatomy documented locations, numbers, and diameters of arteries and skin perforators with surrounding nerves. The palmar cutaneous branch of the median nerve (PCMN) was present within the flap in all cases. However, the LABC and the SSRN were available in only 43.33% and 46.66%, respectively, with neither of them in 33.33% of the cases. The constantly present PCMN allowed the design of a new flap named the radial artery superficial palmar branch (RASP) flap. The RASP flap is large enough to cover volar finger defects and contain direct skin perforators. Because it is constantly innervated, it is an excellent option for coverage of volar finger defects extending to the fingertips. © Thieme Medical Publishers.

  18. Proximally Based Anterolateral-Thigh (ALT) Flap for Knee Reconstruction: An Advancement Propeller Perforator Flap.

    Science.gov (United States)

    Cadenelli, Pierfrancesco; Bordoni, Daniele; Radaelli, Stefano; Marchesi, Andrea

    2015-10-01

    Adequate coverage of the knee region is often challenging for plastic and orthopedic surgeons. In the last decade, among several reconstructive techniques, local perforator flaps have become useful reconstructive units. After a wide resection for soft-tissue sarcoma, the knee vascular web may be reasonably damaged and, consequently, perforator flaps based on a local pedicle [such as the distally based anterolateral thigh (ALT) flap] are not reliable. Thus, we harvested a proximally based ALT for knee coverage. A 52-year-old man underwent local radiation therapy and a wide resection of a soft-tissue sarcoma on the anterior-lateral aspect of the left knee, which resulted in a 15 × 10 cm defect. The defect was covered with a proximally based ALT, through an advancement and propeller relocation of its skin paddle. All margins were tumor free. After 5 days, the donor site was closed primarily because of edema. Neither necrosis of the flap nor dehiscence of the wound was detected. No local relapses were detected at 6-month follow-up. In case of soft-tissue defects of the knee region, with likely involvement of the local vascular web, a local perforator solution is the advancement and propeller proximally based ALT flap. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  19. Temporal-based pericranial flaps for orbitofrontal Dural repair: A technical note and Review of the literature

    Directory of Open Access Journals (Sweden)

    Esther Dupépé

    2016-03-01

    Conclusions: A temporal-based pericranial flap represents an alternative vascularized pedicle flap to the classic frontal-based pericranial flap used in orbitofrontal dural repair. In certain clinical settings, the temporal-based flap may be preferable.

  20. Modeling the Benchmark Active Control Technology Wind-Tunnel Model for Active Control Design Applications

    Science.gov (United States)

    Waszak, Martin R.

    1998-01-01

    This report describes the formulation of a model of the dynamic behavior of the Benchmark Active Controls Technology (BACT) wind tunnel model for active control design and analysis applications. The model is formed by combining the equations of motion for the BACT wind tunnel model with actuator models and a model of wind tunnel turbulence. The primary focus of this report is the development of the equations of motion from first principles by using Lagrange's equations and the principle of virtual work. A numerical form of the model is generated by making use of parameters obtained from both experiment and analysis. Comparisons between experimental and analytical data obtained from the numerical model show excellent agreement and suggest that simple coefficient-based aerodynamics are sufficient to accurately characterize the aeroelastic response of the BACT wind tunnel model. The equations of motion developed herein have been used to aid in the design and analysis of a number of flutter suppression controllers that have been successfully implemented.

  1. Active magnetic levitation guide based on magnetic damping control

    Science.gov (United States)

    Zheng, Zhongqiao; Xu, Minzheng

    2017-07-01

    With the application of active magnetic levitation technology, flutter is a problem in the planar multi-point support system, which reduces the bearing capacity and the control precision, and it is difficult to apply advanced control strategies. Therefore, a new method called magnetic damping control is proposed to solve the flutter problem, which can make active magnetic levitation guide to run smoothly.

  2. [APPLICATION OF DIGITAL TECHNOLOGY IN ANTEROLATERAL THIGH FLAP FOR REPAIRING WOUNDS OF HAND AND FOOT].

    Science.gov (United States)

    Duan, Jiazhang; He, Xiaoqing; Xu, Yongqing; Fan, Xinyu; Luo, Haotian; Wang, Teng; Dong, Kaixuan; Yu, Kaifu

    2015-07-01

    survived completely. All cases were followed up 6-17 months (mean, 9 months). Fifteen flaps had good shape; but a second- stage operation was performed to make the flap thinner in 1 case. At last follow-up, the results were excellent in 3 cases, good in 2 cases, and fair in 1 case according to total active motion (TAM) in 6 cases of hand and forearm injury; the results were excellent in 5 cases, good in 3 cases, and fair in 2 cases according to American Orthopaedic Foot and Ankle Society (AOFAS) in 10 cases of foot injury. The total excellent and good rate was 81.25%. The preoperative individualization design of the flap can be realized through CTA digital technology and Mimics 15.0 software; it can reduce the operation risk.

  3. A prospective, contralateral comparison of photorefractive keratectomy (PRK versus thin-flap LASIK: assessment of visual function

    Directory of Open Access Journals (Sweden)

    Hatch BB

    2011-04-01

    Full Text Available Bryndon B Hatch1, Majid Moshirfar1, Andrew J Ollerton1, Shameema Sikder2, Mark D Mifflin11John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA; 2Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USAPurpose: To compare differences in visual acuity, contrast sensitivity, complications, and higher-order ocular aberrations (HOAs in eyes with stable myopia undergoing either photorefractive keratectomy (PRK or thin-flap laser in situ keratomileusis (LASIK (intended flap thickness of 90 µm using the VISX Star S4 CustomVue excimer laser and the IntraLase FS60 femtosecond laser at 1, 3, and 6 months postoperatively.Methods: In this prospective, masked, and randomized pilot study, refractive surgery was performed contralaterally on 52 eyes: 26 with PRK and 26 with thin-flap LASIK. Primary outcome measures were uncorrected distance visual acuity (UDVA, corrected distance visual acuity (CDVA, contrast sensitivity, and complications.Results: At 6 months, mean values for UDVA (logMAR were -0.043 ± 0.668 and -0.061 ± 0.099 in the PRK and thin-flap LASIK groups, respectively (n = 25, P = 0.466. UDVA of 20/20 or better was achieved in 96% of eyes undergoing PRK and 92% of eyes undergoing thin-flap LASIK, whereas 20/15 vision or better was achieved in 73% of eyes undergoing PRK and 72% of eyes undergoing thin-flap LASIK (P > 0.600. Significant differences were not found between treatment groups in contrast sensitivity (P ≥ 0.156 or CDVA (P = 0.800 at postoperative 6 months. Types of complications differed between groups, notably 35% of eyes in the thin-flap LASIK group experiencing complications, including microstriae and 2 flap tears.Conclusion: Under well-controlled surgical conditions, PRK and thin-flap LASIK refractive surgeries achieve similar results in visual acuity, contrast sensitivity, and induction of HOAs, with differences in experienced complications.Keywords: photorefractive keratectomy, thin-flap LASIK, visual

  4. Shape and Structural Optimization of Flapping Wings

    OpenAIRE

    Stewart, Eric C

    2014-01-01

    This dissertation presents shape and structural optimization studies on flapping wings for micro air vehicles. The design space of the optimization includes the wing planform and the structural properties that are relevant to the wing model being analyzed. The planform design is parameterized using a novel technique called modified Zimmerman, which extends the concept of Zimmerman planforms to include four ellipses rather than two. Three wing types are considered: rigid, plate-like deformable...

  5. Current indications for the osteoplastic flap.

    Science.gov (United States)

    Rivera, Teresa; Rodríguez, Manuel; Pulido, Natalia; García-Alcántara, Fernando; Sanz, Lorena

    2016-01-01

    Endoscopic sinus surgery is the technique of choice in most of the frontal sinus diseases, both inflammatory and tumour-related. This is why the external approach using osteoplastic flap (OF) would be limited to cases with a difficult endoscopic approach. Our aim was to review the current indications of the osteoplastic flap in the treatment of frontal sinus pathology, through a retrospective study of patients undergoing this technique. We performed a retrospective study of 14 patients who were treated with the osteoplastic flap procedure. All the surgical indication criteria, type of sinus disease, presence or absence of prior endoscopic surgery, surgical findings, complications and recurrence were reviewed. The pathologies found were 1 osteoma (7.1%), 3 inverted papilloma (21.4%) and 10 mucoceles (71.4%). Nine patients had a prior endoscopic surgery and 10 patients had an orbital dehiscence (9 mucocele, 1 papilloma). Frontal osteoma was Grade IV and the papilloma cases were Krouse Stage III. Surgical revision was required for 21.4%. The main indications for an OF in patients with inflammatory disease are lateral extension and frontal recess neo-osteogenesis. In osteoma cases, it depends on the size of the tumour. In inverted papilloma cases, the indication is multifocal implantation with origin in the anterior and lateral wall. In all cases, performing the osteoplastic flap must be individualised. Copyright © 2014 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Patología Cérvico-Facial. All rights reserved.

  6. A New Method for Creating the Bladder Flap

    Directory of Open Access Journals (Sweden)

    Alexandria J. Hill

    2013-01-01

    Full Text Available Background Bladder flaps are commonly created during routine cesarean deliveries and often require multiple steps that increase operating time and expose the surgeon to inadvertent injury. Objective We report a simple method of creating a bladder flap that eliminates the need for multiple instrument handoffs and repositioning. Conclusion The simplicity of this method allows the surgeon decreased operative entry time while decreasing exposure to injuries from multiple instrument handoffs during bladder flap development.

  7. Interpolated conjunctival pedicle flaps for the treatment of exposed glaucoma drainage devices.

    Science.gov (United States)

    Godfrey, David G; Merritt, James H; Fellman, Ronald L; Starita, Richard J

    2003-12-01

    To describe an alternative method to repair exposed glaucoma drainage devices (GDDs) when conventional attempts have failed. Four eyes, from 3 patients, with severe ocular surface disease were included in the study. All eyes had previously received a Baerveldt GDD for uncontrollable intraocular pressure and postoperatively had exposed GDDs. The conjunctival defects were unrepairable with a scleral patch or pericardium, conjunctival advancement, or a conjunctival patch graft. Two eyes had chemical burns, one eye had extensive scarring from multiple surgical procedures, and one patient had rheumatoid arthritis. Each patient provided informed consent, and was given the option of removing the GDD and undergoing diode cyclophotocoagulation or attempting to save the GDD by a conjunctival pedicle flap. An interpolated conjunctival pedicle flap was taken from the cul-de-sac (fornix). The conjunctiva and Tenon capsule were incised radially to the tube, rotated from the fornix at a 90 degrees angle, and sutured to the remaining healthy conjunctiva to cover the exposed tube. Postoperatively, all eyes had vascularized flaps that showed viable tissue. All eyes retained the GDDs, and the intraocular pressure has been under control during follow-up (7, 13, 25, and 27 months). Interpolated conjunctival pedicle flaps seem to be a viable alternative to repairing exposed GDDs when other methods are impractical or impossible.

  8. Mastectomy skin flap necrosis: challenges and solutions

    Science.gov (United States)

    Robertson, Stuart A; Jeevaratnam, Johann A; Agrawal, Avi; Cutress, Ramsey I

    2017-01-01

    Introduction Mastectomy skin flap necrosis (MSFN) has a reported incidence of 5%–30% in the literature. It is often a significant and underappreciated problem. The aim of this article was to review the associated challenges and possible solutions. Methods A MEDLINE search was performed using the search term “mastectomy skin flap necrosis”. Titles and abstracts from peer-reviewed publications were screened for relevance. Results MSFN is a common complication and may present as partial- or full-thickness necrosis. Predictive patient risk factors include smoking, diabetes, obesity, radiotherapy, previous scars and severe medical comorbidity. MSFN leads to a number of challenges, including wound management problems, delays to adjuvant therapy, esthetic compromise, implant extrusion, patient distress and financial loss. Careful preoperative planning and meticulous surgical technique may reduce the incidence of MSFN. A number of intraoperative techniques are available to try and predict skin flaps at risk of MSFN. MSFN may be managed operatively or nonoperatively. Early intervention may reduce the morbidity of MSFN in selected cases. Topical nitroglycerin ointment may be beneficial in reducing MSFN following immediate reconstruction, but the evidence base is still limited. Conclusion MSFN can result in considerable challenges for the patient and the health care service. This review discusses the management options for this problem. PMID:28331365

  9. The extended abdominal wall flap for transplantation.

    Science.gov (United States)

    Hollenbeck, S T; Senghaas, A; Turley, R; Ravindra, K V; Zenn, M R; Levin, L S; Erdmann, D

    2011-06-01

    Patients with extensive loss of the abdominal wall tissue have few options for restoring the abdominal cavity. Composite tissue allotransplantation has been used for limited abdominal wall reconstruction in the setting of visceral transplantation, yet replacement of the entire abdominal wall has not been described. The purpose of this study was to determine the maximal abdominal skin surface available through an external iliac/femoral cuff-based pedicle. Five human cadaveric abdominal walls were injected with methylene blue to analyze skin perfusion based on either the deep inferior epigastric artery (DIEA; n = 5) or a cuff of external iliac/femoral artery (n = 5) containing the deep circumflex iliac, deep inferior epigastric, and superficial inferior epigastric, and superficial circumflex iliac arteries. Abdominal wall flaps were taken full thickness from the costal margin to the midaxillary line and down to the pubic tubercle and proximal thigh. In all specimens, the deep inferior epigastric, deep circumflex iliac, superficial inferior epigastric, and superficial circumflex iliac arteries were found to originate within a 4-cm cuff of the external iliac/femoral artery. Abdominal wall flaps injected through a unilateral external iliac/femoral segment had a significantly greater degree of total flap perfusion than those injected through the DIEA alone (76.5% ± 4% vs 57.2% ± 5%; Student t test, P DIEA vessel alone. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Tuning of active vibration controllers for ACTEX by genetic algorithm

    Science.gov (United States)

    Kwak, Moon K.; Denoyer, Keith K.

    1999-06-01

    This paper is concerned with the optimal tuning of digitally programmable analog controllers on the ACTEX-1 smart structures flight experiment. The programmable controllers for each channel include a third order Strain Rate Feedback (SRF) controller, a fifth order SRF controller, a second order Positive Position Feedback (PPF) controller, and a fourth order PPF controller. Optimal manual tuning of several control parameters can be a difficult task even though the closed-loop control characteristics of each controller are well known. Hence, the automatic tuning of individual control parameters using Genetic Algorithms is proposed in this paper. The optimal control parameters of each control law are obtained by imposing a constraint on the closed-loop frequency response functions using the ACTEX mathematical model. The tuned control parameters are then uploaded to the ACTEX electronic control electronics and experiments on the active vibration control are carried out in space. The experimental results on ACTEX will be presented.

  11. Position dependent rate dampening in any active hand controller

    Science.gov (United States)

    Gregory, William W. (Inventor); Kauffman, James W. (Inventor)

    1994-01-01

    A control system for an active hand controller, for example, uses a control stick connected to and controlled by a motor. Electronics are provided to control the motor to eliminate oscillations due to motor torque and high gain due to breakout at the control stick when the control stick is at about its null position. Both hardware as well as software implementations can provide position dependent dampening to the control sticks such that when the control stick is located about a null position, a higher rate of dampening is provided than when the control stick is located outside the null position, when a lower rate of dampening is provided. The system provides a stable active hand controller control stick without degraded force and feel characteristics of the system.

  12. Perineoscrotal reconstruction using a medial circumflex femoral artery perforator flap.

    Science.gov (United States)

    Karsidag, Semra; Akcal, Arzu; Sirvan, Selami Serhat; Guney, Soner; Ugurlu, Kemal

    2011-02-01

    Major scrotal defects may result from infection due to Fournier's gangrene, excision of scrotal skin diseases, traumatic avulsion of scrotal and penile skin, and genital burns. The wide spectrum of bacterial flora of the perineum, difficulty in providing immobilisation, and obtaining a natural contour of the testes make testicular cover very difficult. Various methods have been reported to cover the penoscrotal area, including skin grafting, transposing them to medial thigh skin, and use of local fasciocutaneous or musculocutaneous flaps. In this report, reconstruction using six local medial circumflex femoral artery perforator (MCFAP) flaps was undertaken in five male patients (mean age, 47 years) with complex penoscrotal or perineal wounds. The cause of the wounds in four patients was Fournier's gangrene, and was a wide papillomateous lesion in the other patient. Flap width was 6-10 cm and flap length was 10-18 cm. The results showed that a MCFAP flap provided the testes with a pliable local flap without being bulky and also protected the testicle without increasing the temperature. The other advantage of the MCFAP flap was that the donor-site scar could be concealed in the gluteal crease. Our results demonstrated that the MCFAP flap is an ideal local flap for covering penoscrotal defects. Copyright © 2011 Wiley-Liss, Inc.

  13. Reconstruction of scalp defects with the radial forearm free flap

    Science.gov (United States)

    2012-01-01

    Background Advanced and recurrent cutaneous squamous cell carcinoma of the scalp and forehead require aggressive surgical excision often resulting in complex defects requiring reconstruction. This study evaluates various microvascular free flap reconstructions in this patient population, including the rarely utilized radial forearm free flap. Patients and methods A retrospective review of patients undergoing free flap surgeries (n = 47) of the scalp between 1997 and 2011 were included. Patients were divided primarily into two cohorts: a new primary lesion (n = 21) or recurrence (n = 26). Factors examined include patient demographics, indication for surgery, defect, type of flap used, complications (major and minor), and outcomes. Results The patients were primarily male (n = 34), with a mean age of 67 years (25–91). A total of 58 microvascular free flap reconstructions were performed (radial forearm free flap: n = 28, latissimus dorsi: n = 20, rectus abdominis: n = 9, scapula: n = 1). Following reconstruction with a radial forearm free flap, duration of hospitalization was shorter (P = 0.04) and complications rates were similar (P = 0.46). Donor site selection correlated with defect area (P scalp are aggressive and challenging to treat. The radial forearm free flap is an underutilized free flap in the reconstruction of complex scalp defects. PMID:22583845

  14. Dorsal hand coverage with free serratus fascia flap

    DEFF Research Database (Denmark)

    Fotopoulos, Peter; Holmer, Per; Leicht, Pernille

    2003-01-01

    In reconstructing a defect on the dorsum of the hand, with the extensor tendons exposed or even missing, functional, as well as cosmetic, goals are of major importance. The authors present three cases of extensor tendon reconstruction, combined with soft-tissue reconstruction, with the free...... in the flap, leaving the long thoracic nerve intact on the serratus muscle. Coverage of the flap with split-thickness skin graft is done immediately. The free serratus fascia flap is an ideal flap for dorsal hand coverage when the extensor tendons are exposed, especially because of low donor-site morbidity....

  15. Cervicopectoral flap in head and neck cancer surgery

    Directory of Open Access Journals (Sweden)

    Sivrioglu Nazan S

    2003-12-01

    Full Text Available Abstract Background Reconstruction of the head and neck after adequate resection of primary tumor and neck dissection is a challenge. It should be performed at one sitting in advanced tumors. Defects caused by the resection should be closed with flaps which match in color, texture and hair bearing characteristics with the face. Cervicopectoral flap is a one such flap from chest and neck skin mainly used to cover the cheek defects. Methods This study included twelve patients presenting with cancer of the head and neck to Izmir Ataturk Training Hospital and Adnan Menderes University Hospital. Tumor resection and neck dissection was performed in one session by the same surgeon. A single incision was made and a medially based cervicopectoral fascio-cutaneous flap was used for surgical exposure in neck dissection and for closure of defects after tumor resection. Results There was no major complication. Two flaps had partial superficial epidermolysis at the suture line. Good aesthetic and functional results were achieved. Conclusion The cervicopectoral flap is an excellent alternative for the reconstruction of head and neck. Harvesting and application of the flap is rapid and safe. Only a single incision is sufficient for dissection and flap elevation. This flap achieves perfect surgical exposure, makes neck dissection easy and allows one to perform both tumor resection and neck dissection in one session.

  16. Rotational flaps in oncologic breast surgery. Anatomical and technical considerations.

    Science.gov (United States)

    Acea Nebril, Benigno; Builes Ramírez, Sergio; García Novoa, Alejandra; Varela Lamas, Cristina

    2016-01-01

    Local flaps are a group of surgical procedures that can solve the thoracic closure of large defects after breast cancer surgery with low morbidity. Its use in skin necrosis complications after conservative surgery or skin sparing mastectomies facilitates the initiation of adjuvant treatments and reduces delays in this patient group. This article describes the anatomical basis for the planning of thoracic and abdominal local flaps. Also, the application of these local flaps for closing large defects in the chest and selective flaps for skin coverage by necrosis in breast conserving surgery. Copyright © 2016 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  17. Modeling stability of flap-enabled HAWT blades using spinning finite elements

    Science.gov (United States)

    Velazquez, A.; Swartz, R. Andrew; Dai, Qingli; Sun, Xiao

    2014-04-01

    Horizontal-axis wind turbines (HAWTs) are growing in size and popularity for the generation of renewable energy to meet the world's ever increasing demand. Long-term safety and stability are major concerns related to the construction and use-phase of these structures. Braking and active pitch control are important tools to help maintain safe and stable operation, however variable cross-section control represents another possible tool as well. To properly evaluate the usefulness of this approach, modeling tools capable of representing the dynamic behavior of blades with conformable cross sections are necessary. In this study, a modeling method for representing turbine blades as a series of interconnected spinning finite elements (SPEs) is presented where the aerodynamic properties of individual elements may be altered to represent changes in the cross section due to conformability (e.g., use of a mechanical flap or a "smart" conformable surface). Such a model is expected to be highly valuable in design of control rules for HAWT blades with conformable elements. Sensitivity and stability of the modeling approach are explored.

  18. Large-Scale Wind-Tunnel Tests of Inverting Flaps on a STOL Utility Aircraft Model.

    Science.gov (United States)

    1980-06-01

    instru- mented flap supports and exhibited acceptable behavior. Integral spoilers were investigated for lateral control and were found to produce...and 60/32 inboard - 90/37 outboard, with a nomina free-stream dynamic pressure of 192 N/m 2 (4 psf) and with nominal thrust coefficients of 0, 1...panel only, as shown in fig- ures 2(a) and 2(c) and was deflected 400 from the nesting position for the lateral control effective- ness tests. The

  19. Active magnetic bearing system based on sliding mode control

    Science.gov (United States)

    Zhang, Yanhong

    2017-07-01

    A new sliding mode variable structure control algorithm suitable for active magnetic bearing is proposed, which is widely used for nonlinear control system. The model and controller is designed, simulation and experimental parts are also made, according to the switching function and the sliding mode control law. The current of electromagnet is adjusted to realize stable levitation of the rotor. The experimental result shows that the sliding mode variable structure controller is an effective way for magnetic bearing control, and the active magnetic bearing system is a highly nonlinear and advanced control method that can reduce the setting time and the cost.

  20. Short Horizon Control Strategies for an Alternating Activated Sludge Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard

    1996-01-01

    Three control strategies allowing improved operational flexibility of an alternating type activated sludge process are presented in a unified model based framework. The control handles employed are the addition rate of an external carbon source to denitrification, the cycle length...

  1. Modeling the effects of control systems of wind turbine fatigue life

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, K.G.; Laino, D.J. [Univ. of Utah, Salt Lake City, UT (United States)

    1996-12-31

    In this study we look at the effect on fatigue life of two types of control systems. First, we investigate the Micon 65, an upwind, three bladed turbine with a simple yaw control system. Results indicate that increased fatigue damage to the blade root can be attributed to continuous operation at significant yaw error allowed by the control system. Next, we model a two-bladed teetered rotor turbine using three different control systems to adjust flap deflections. The first two limit peak power output, the third limits peak power and cyclic power output over the entire range of operation. Results for simulations conducted both with and without active control are compared to determine how active control affects fatigue life. Improvement in fatigue lifetimes were seen for all control schemes, with increasing fatigue lifetime corresponding to increased flap deflection activity. 13 refs., 6 figs., 2 tabs.

  2. Optimization design and dynamic analysis on the drive mechanisms of flapping-wing air vehicles based on flapping trajectories

    Science.gov (United States)

    Xie, Lingwang; Zhang, Xingwei; Luo, Pan; Huang, Panpan

    2017-10-01

    The optimization designs and dynamic analysis on the driving mechanism of flapping-wing air vehicles on base of flapping trajectory patterns is carried out in this study. Three different driving mechanisms which are spatial double crank-rocker, plane five-bar and gear-double slider, are systematically optimized and analysed by using the Mat lab and Adams software. After a series debugging on the parameter, the comparatively ideal flapping trajectories are obtained by the simulation of Adams. Present results indicate that different drive mechanisms output different flapping trajectories and have their unique characteristic. The spatial double crank-rocker mechanism can only output the arc flapping trajectory and it has the advantages of small volume, high flexibility and efficient space utilization. Both planar five-bar mechanism and gear-double slider mechanism can output the oval, figure of eight and double eight flapping trajectories. Nevertheless, the gear-double slider mechanism has the advantage of convenient parameter setting and better performance in output double eight flapping trajectory. This study can provide theoretical basis and helpful reference for the design of the drive mechanisms of flapping-wing air vehicles with different output flapping trajectories.

  3. Clinical efficacy of coronally advanced flap with or without connective tissue graft for the treatment of multiple adjacent gingival recessions in the aesthetic area: a randomized controlled clinical trial.

    Science.gov (United States)

    Cairo, Francesco; Cortellini, Pierpaolo; Pilloni, Andrea; Nieri, Michele; Cincinelli, Sandro; Amunni, Franco; Pagavino, Gabriella; Tonetti, Maurizio S

    2016-10-01

    The aim of this study was to assess the clinical efficacy of coronally advanced flap (CAF) with or without connective tissue graft (CTG) for the treatment of multiple adjacent gingival recessions in the upper arch. Thirty-two patients with a total of 74 gingival recessions were randomly allocated to the two groups. Outcome measures, collected by a blind examiner, included complete root coverage (CRC), recession reduction (RecRed), keratinized tissue (KT) gain, increase in gingival thickness (GT), patient satisfaction and root coverage esthetic score (RES). An interaction between treatment and baseline GT was detected. At 1 year, CAF + CTG resulted in better outcomes in terms of CRC (p = 0.0016) and RecRed (p 0.8 mm). CAF resulted in higher aesthetic scores (RES) than CAF + CTG at sites with thick gingiva. CAF + CTG was associated with greater KT gain (p Connective tissue graft under CAF results in increased probability of CRC only at sites with thin baseline gingiva. CAF alone is associated with similar clinical outcomes and better aesthetics at sites with thick baseline gingiva. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Controller modification applied for active fault detection

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob; Poulsen, Niels Kjølstad

    2014-01-01

    with the result that the detection and isolation time can be long. In this paper it will be shown, that this problem can be handled by using a modification of the feedback controller. By applying the YJBK-parameterization (after Youla, Jabr, Bongiorno and Kucera) for the controller, it is possible to modify...... the feedback controller with a minor effect on the external output in the fault free case. Further, in the faulty case, the signature of the auxiliary input can be optimized. This is obtained by using a band-pass filter for the YJBK parameter that is only effective in a small frequency range where...... the frequency for the auxiliary input is selected. This gives that it is possible to apply an auxiliary input with a reduced amplitude. An example is included to show the results....

  5. Formal Verification of Effectiveness of Control Activities in Business Processes

    Science.gov (United States)

    Arimoto, Yasuhito; Iida, Shusaku; Futatsugi, Kokichi

    It has been an important issue to deal with risks in business processes for achieving companies' goals. This paper introduces a method for applying a formal method to analysis of risks and control activities in business processes in order to evaluate control activities consistently, exhaustively, and to give us potential to have scientific discussion on the result of the evaluation. We focus on document flows in business activities and control activities and risks related to documents because documents play important roles in business. In our method, document flows including control activities are modeled and it is verified by OTS/CafeOBJ Method that risks about falsification of documents are avoided by control activities in the model. The verification is done by interaction between humans and CafeOBJ system with theorem proving, and it raises potential to discuss the result scientifically because the interaction gives us rigorous reasons why the result is derived from the verification.

  6. Broadband Radiation Modes: Estimation and Active Control

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    In this paper we give a formulation of the most efficiently radiating vibration patterns of a vibrating body, the radiation modes, in the time domain. The radiation modes can be used to arrive at efficient weighting schemes for an array of sensors in order to reduce the controller dimensionality.

  7. Selective Activation and Disengagement of Moral Control.

    Science.gov (United States)

    Bandura, Albert

    1990-01-01

    Analyzes psychological mechanisms by which moral control is selectively disengaged from inhumane conduct in ordinary and unusual circumstances. Explores the symptoms of moral exclusion as described in the literature. Presents categories that unify theory on moral exclusion and contribute practical classifications for use in empirical studies. (JS)

  8. ACOSS-16 (Active Control of Space Structures)

    Science.gov (United States)

    1982-10-01

    At NTIS it will be releasable to the general public, including foreign nations. Some of the machine-produced data are of poor quality reproduction...is extremely sensitive t9 additionaldesign model uncertainty. "o Higher contril b•andwidth would improve its control performance, but would require

  9. Practical Considerations for Perforator Flap Thinning Procedures Revisited

    Directory of Open Access Journals (Sweden)

    Theddeus OH Prasetyono

    2014-11-01

    Full Text Available BackgroundA thin perforator flap is one of the best methods for covering defects. This study aimed to revisit and further test the rapidly advancing field of flap thinning techniques.MethodsWe performed two cadaveric studies to test the known flap thinning methods, and then applied these methods to a clinical series. In the first study, five cadavers were used to observe the anatomical relation of the perforator with the subdermal plexuses and the subcutaneous fat layer by injecting a colored latex solution. The second study was done on four cadavers independently from the first study. Last, a clinical series was performed on 15 patients.ResultsThe areolar fat lobules of 10 anterolateral thigh perforator (ALT, seven deep inferior epigastric artery perforator (DIEAP, and six thoracodorsal artery perforator (TAP flaps were dissected to reduce the flap thickness guided by the colored vascular pattern. On average, the ALT, DIEAP, and TAP flaps were reduced to 32.76%±9.76%, 37.01%±9.21%, and 35.42%±9.41%, respectively. In the second study, the areolar fat lobules were directly dissected in six ALT, six TAP, and four MSAP flaps, and an average reduction in flap thickness of 53.41%±5.64%, 52.30%±2.88%, and 47.87%±6.41%, respectively, was found. In the clinical series, 13 out of the 15 cases yielded satisfactory outcomes with an average thickness reduction of 37.91%±7.15%.ConclusionsThese multiple studies showed that the deep fat layer could be safely removed to obtain a thin yet viable perforator flap. This evidence suggests that the macroscopic flap thinning technique can achieve thin flaps. Surgeons should consider this technique before embracing the latest technique of supermicrosurgery.

  10. A CFD-informed quasi-steady model of flapping wing aerodynamics.

    Science.gov (United States)

    Nakata, Toshiyuki; Liu, Hao; Bomphrey, Richard J

    2015-11-01

    Aerodynamic performance and agility during flapping flight are determined by the combination of wing shape and kinematics. The degree of morphological and kinematic optimisation is unknown and depends upon a large parameter space. Aimed at providing an accurate and computationally inexpensive modelling tool for flapping-wing aerodynamics, we propose a novel CFD (computational fluid dynamics)-informed quasi-steady model (CIQSM), which assumes that the aerodynamic forces on a flapping wing can be decomposed into the quasi-steady forces and parameterised based on CFD results. Using least-squares fitting, we determine a set of proportional coefficients for the quasi-steady model relating wing kinematics to instantaneous aerodynamic force and torque; we calculate power with the product of quasi-steady torques and angular velocity. With the quasi-steady model fully and independently parameterised on the basis of high-fidelity CFD modelling, it is capable of predicting flapping-wing aerodynamic forces and power more accurately than the conventional blade element model (BEM) does. The improvement can be attributed to, for instance, taking into account the effects of the induced downwash and the wing tip vortex on the force generation and power consumption. Our model is validated by comparing the aerodynamics of a CFD model and the present quasi-steady model using the example case of a hovering hawkmoth. It demonstrates that the CIQSM outperforms the conventional BEM while remaining computationally cheap, and hence can be an effective tool for revealing the mechanisms of optimization and control of kinematics and morphology in flapping-wing flight for both bio-flyers and unmanned air systems.

  11. Lightning protection of flap system for wind turbine blades

    OpenAIRE

    Candela Garolera, Anna; Holbøll, Joachim; Madsen, Søren Find

    2014-01-01

    Formålet med dette ph.d.-projekt har været at undersøge hvordan en Controllable Rubber Trailing Edge Flap (CRTEF) i en vindmøllevinge reagerer, når den bliver udsat for lynnedslag og finde den bedste tekniske løsning til at beskytte CRTEF’en og kontrolsystemet mod lyn, på baggrund af resultater fra simuleringsmodeller og højspændingsprøver.Vindmøller er ofte udsat for lynnedslag på grund af deres højde og placering, og vingerne er den del, der er mest udsat for direkte udladninger. At beskytt...

  12. Genetic control of active neural circuits

    Directory of Open Access Journals (Sweden)

    Leon Reijmers

    2009-12-01

    Full Text Available The use of molecular tools to study the neurobiology of complex behaviors has been hampered by an inability to target the desired changes to relevant groups of neurons. Specific memories and specific sensory representations are sparsely encoded by a small fraction of neurons embedded in a sea of morphologically and functionally similar cells. In this review we discuss genetics techniques that are being developed to address this difficulty. In several studies the use of promoter elements that are responsive to neural activity have been used to drive long lasting genetic alterations into neural ensembles that are activated by natural environmental stimuli. This approach has been used to examine neural activity patterns during learning and retrieval of a memory, to examine the regulation of receptor trafficking following learning and to functionally manipulate a specific memory trace. We suggest that these techniques will provide a general approach to experimentally investigate the link between patterns of environmentally activated neural firing and cognitive processes such as perception and memory.

  13. Effect of Flap Mutations on Structure of HIV-1 Protease and Inhibition by Sanquinavir and Darunavir

    Energy Technology Data Exchange (ETDEWEB)

    Liu, F.; Kovalevsky, A.; Tie, Y.; Ghosh, A.; Harrison, R.; Weber, I. (GSU); (Purdue)

    2008-08-25

    HIV-1 (human immunodeficiency virus type 1) protease (PR) and its mutants are important antiviral drug targets. The PR flap region is critical for binding substrates or inhibitors and catalytic activity. Hence, mutations of flap residues frequently contribute to reduced susceptibility to PR inhibitors in drug-resistant HIV. Structural and kinetic analyses were used to investigate the role of flap residues Gly48, Ile50, and Ile54 in the development of drug resistance. The crystal structure of flap mutants PR{sub I50V} (PR with I50V mutation), PR{sub I54V} (PR with I54V mutation), and PR{sub I54M} (PR with I54M mutation) complexed with saquinavir (SQV) as well as PR{sub G48V} (PR with G48V mutation), PR{sub I54V}, and PR{sub I54M} complexed with darunavir (DRV) were determined at resolutions of 1.05--1.40 {angstrom}. The PR mutants showed changes in flap conformation, interactions with adjacent residues, inhibitor binding, and the conformation of the 80s loop relative to the wild-type PR. The PR contacts with DRV were closer in PR{sub G48V}-DRV than in the wild-type PR-DRV, whereas they were longer in PR{sub I54M}-DRV. The relative inhibition of PR{sub I54V} and that of PR{sub I54M} were similar for SQV and DRV. PR{sub G48V} was about twofold less susceptible to SQV than to DRV, wheres the opposite was observed for PR{sub I50V}. The observed inhibition was in agreement with the association of G48V and I50V with clinical resistance to SQV and DRV, respectively. This analysis of structural and kinetic effects of the mutants will assist in the development of more effective inhibitors for drug-resistant HIV.

  14. Deltoid muscular flap transfer for the treatment of irreparable rotator cuff tears

    Directory of Open Access Journals (Sweden)

    Justus Gille

    2009-09-01

    Full Text Available The purpose of this study was to evaluate the outcome of deltoid muscle flap transfer for the treatment of irreparable rotator cuff tears. In a retrospective study 20 consecutive patients were evaluated. The index procedure took place between 2000 and 2003. Fifteen patients were male, mean age was 62 years. Inclusion criterion was a rotator cuff defect Bateman grade IV. Exclusion criteria were smaller defects, shoulder instability and fractures of the injured shoulder. An open reconstruction with acromioplasty and a pedicled delta flap was performed. Follow up period was mean 42 months. Follow-up included clinical examination, Magnetic Resonance Imaging (MRI and the Constant and Simple (CS shoulder tests. According to the Constant shoulder test the results were good in 13 patients, fair in 5 and unsatisfactory in 2. The pre-operative Constant Score improved from mean 25.7 points (±5.3 to 72.3 (±7.8 at follow-up. The mean values for the subcategories of CS increased significantly from 3.9 to 14.4 points for pain and from 4.2 to 15.9 points for activities daily routine (p0.05. Results of the Simple Shoulder Test showed a significant increase of the mean values from pre-operative 4.3 to 14.7 points post-operatively. MRI showed a subacromial covering of the defect in all cases, all flaps where intact on MRI but always the flap showed marked fatty degeneration. In conclusion, the delta flap is a simple method for the repair of large defects of the rotator cuff leading to satisfying medium results.

  15. Foundations of Active Control - Active Noise Reduction Helmets

    DEFF Research Database (Denmark)

    Elmkjær, Torsten Haaber Leth

    2008-01-01

    a detailed description of a new idea for a computational efficient implementation of a multi-channel system in which the adaptive filters for adaptive control as well as the adaptive filters used for plant modeling are allowing to take different lengths. A new and more general variant of the affine...... of this algorithm leads to the MC-αγΠ-NLMS algorithm that is an extended variant of the NLMS algorithm. Off-line simultaneous system identification capabilities of a complex system involving a total 4 secondary paths, 20 feedback paths and 4 control-performance paths is demonstrated. Different adaptive filters...... and parameterizations hereof are examined. A novel and general multi-rate adaptive filter for adaptive AC has been developed. Specifically, a system involving 3 different sampling rates has been implemented and the results hereof are presented. In this multi-rate system conversion take place at highly oversampled rates...

  16. Active control of noise radiation from vibrating structures

    DEFF Research Database (Denmark)

    Mørkholt, Jakob

    The thesis is concerned with the active control of randomly vibrating structures by means of feedback control, with particular emphasis on reducing the sound radiation from such structures. A time domain model of the structural and radiation dynamics of an actively controlled plate has been...... optimal and robust discrete-time feedback controllers for active vibration control of multimodal structures have been compared. They have been showed to yield controllers with identical frequency response characteristics, even though they employ completely different methods of numerical solutions...... developed, based on the theory of radiation filters for estimating the sound radiation from multimodal vibrations. This model has then been used in simulations of optimal feedback control, with special emphasis of the stability margins of the optimal control scheme. Two different methods of designing...

  17. Geometric Methods for Controlled Active Vision

    Science.gov (United States)

    2012-02-07

    learning for neonate pain intensity assessment using digital imaging” (with B. Gholami and W. Haddad), IEEE Trans. Biomedical Engineering 57 (2010), pp...for cardiopulmonary management and intensive care unit sedation using expert systems,” (with B. Gholami, W. Haddad, J. Bailey), to appear in IEEE...stabilized visual closed-loop tracking” (with P. Karasev and P. Vela), Proceedings ACC, 2010. 55. ”Closed-loop control for intensive care unit sedation

  18. Mission control activity during STS-61 EVA

    Science.gov (United States)

    1993-01-01

    Flight Director Milton Heflin monitors two space walkers as they change out the Wide Field/Planetary Camera (WF/PC) on the Hubble Space Telescope (HST), temporarily berthed in Endeavour's cargo bay. Astronaut Gregory J. Harbaugh, spacecraft communicator (CAPCOM), is at right edge. Astronauts F. Story Musgrave and Jeffrey A. Hoffman can be seen with the large camera on the screen in the front of the flight control room.

  19. Hybrid Architecture Active Wavefront Sensing and Control

    Science.gov (United States)

    Feinberg, Lee; Dean, Bruce; Hyde, Tupper

    2010-01-01

    A method was developed for performing relatively high-speed wavefront sensing and control to overcome thermal instabilities in a segmented primary mirror telescope [e.g., James Webb Space Telescope (JWST) at L2], by using the onboard fine guidance sensor (FGS) to minimize expense and complexity. This FGS performs centroiding on a bright star to feed the information to the pointing and control system. The proposed concept is to beam split the image of the guide star (or use a single defocused guide star image) to perform wavefront sensing using phase retrieval techniques. Using the fine guidance sensor star image for guiding and fine phasing eliminates the need for other, more complex ways of achieving very accurate sensing and control that is needed for UV-optical applications. The phase retrieval occurs nearly constantly, so passive thermal stability over fourteen days is not required. Using the FGS as the sensor, one can feed segment update information to actuators on the primary mirror that can update the primary mirror segment fine phasing with this frequency. Because the thermal time constants of the primary mirror are very slow compared to this duration, the mirror will appear extremely stable during observations (to the level of accuracy of the sensing and control). The sensing can use the same phase retrieval techniques as the JWST by employing an additional beam splitter, and having each channel go through a weak lens (one positive and one negative). The channels can use common or separate detectors. Phase retrieval can be performed onboard. The actuation scheme would include a coarse stage able to achieve initial alignment of several millimeters of range (similar to JWST and can use a JWST heritage sensing approach in the science camera) and a fine stage capable of continual updates.

  20. Robust design of multiple trailing edge flaps for helicopter vibration reduction: A multi-objective bat algorithm approach

    Science.gov (United States)

    Mallick, Rajnish; Ganguli, Ranjan; Seetharama Bhat, M.

    2015-09-01

    The objective of this study is to determine an optimal trailing edge flap configuration and flap location to achieve minimum hub vibration levels and flap actuation power simultaneously. An aeroelastic analysis of a soft in-plane four-bladed rotor is performed in conjunction with optimal control. A second-order polynomial response surface based on an orthogonal array (OA) with 3-level design describes both the objectives adequately. Two new orthogonal arrays called MGB2P-OA and MGB4P-OA are proposed to generate nonlinear response surfaces with all interaction terms for two and four parameters, respectively. A multi-objective bat algorithm (MOBA) approach is used to obtain the optimal design point for the mutually conflicting objectives. MOBA is a recently developed nature-inspired metaheuristic optimization algorithm that is based on the echolocation behaviour of bats. It is found that MOBA inspired Pareto optimal trailing edge flap design reduces vibration levels by 73% and flap actuation power by 27% in comparison with the baseline design.

  1. The accuracy of computer-assisted primary mandibular reconstruction with vascularized bone flaps: iliac crest bone flap versus osteomyocutaneous fibula flap

    Directory of Open Access Journals (Sweden)

    Modabber A

    2014-06-01

    Full Text Available Ali Modabber,1 Nassim Ayoub,1 Stephan Christian Möhlhenrich,1 Evgeny Goloborodko,1 Tolga Taha Sönmez,1 Mehrangiz Ghassemi,2 Christina Loberg,3 Bernd Lethaus,1 Alireza Ghassemi,1 Frank Hölzle1 1Department of Oral, Maxillofacial and Plastic Facial Surgery, 2Department of Orthodontics, 3Department of Diagnostic and Interventional Radiology, RWTH Aachen University Hospital, Aachen, Germany Background: The intention of mandibular reconstruction is to restore the complex anatomy with maximum possible functionality and high accuracy. The aim of this study was to evaluate the accuracy of computer-assisted surgery in primary mandibular reconstruction with an iliac crest bone flap compared with an osteomyocutaneous fibula flap. Materials and methods: Preoperative computed tomography data of the mandible and the iliac crest or fibula donor site were imported into a specific surgical planning software program. Surgical guides were manufactured using a rapid prototyping technique for translating the virtual plan, including information on the transplant dimensions and shape, into real-time surgery. Using postoperative computed tomography scans and an automatic surface-comparison algorithm, the actual postoperative situation was compared with the preoperative virtual simulation. Results: The actual flap position showed a mean difference from the virtual plan of 2.43 mm (standard deviation [SD] ±1.26 and a surface deviation of 39% <2 mm and 15% <1 mm for the iliac crest bone flap, and a mean difference of 2.18 mm (SD ±1.93 and a surface deviation of 60% <2 mm and 37% <1 mm for the osteomyocutaneous fibula flap. The position of the neomandible reconstructed with an osteomyocutaneous fibula flap indicated a mean difference from the virtual plan of 1.25 mm (SD ±1.31 and a surface deviation of 82% <2 mm and 57% <1 mm, in contrast to a mean difference of 1.68 mm (SD ±1.25 and a surface deviation of 63% <2 mm and 38% <1 mm for the neomandible after

  2. Cysteine Biosynthesis Controls Serratia marcescens Phospholipase Activity.

    Science.gov (United States)

    Anderson, Mark T; Mitchell, Lindsay A; Mobley, Harry L T

    2017-08-15

    Serratia marcescens causes health care-associated opportunistic infections that can be difficult to treat due to a high incidence of antibiotic resistance. One of the many secreted proteins of S. marcescens is the PhlA phospholipase enzyme. Genes involved in the production and secretion of PhlA were identified by screening a transposon insertion library for phospholipase-deficient mutants on phosphatidylcholine-containing medium. Mutations were identified in four genes (cyaA, crp, fliJ, and fliP) that are involved in the flagellum-dependent PhlA secretion pathway. An additional phospholipase-deficient isolate harbored a transposon insertion in the cysE gene encoding a predicted serine O-acetyltransferase required for cysteine biosynthesis. The cysE requirement for extracellular phospholipase activity was confirmed using a fluorogenic phospholipase substrate. Phospholipase activity was restored to the cysE mutant by the addition of exogenous l-cysteine or O-acetylserine to the culture medium and by genetic complementation. Additionally, phlA transcript levels were decreased 6-fold in bacteria lacking cysE and were restored with added cysteine, indicating a role for cysteine-dependent transcriptional regulation of S. marcescens phospholipase activity. S. marcescenscysE mutants also exhibited a defect in swarming motility that was correlated with reduced levels of flhD and fliA flagellar regulator gene transcription. Together, these findings suggest a model in which cysteine is required for the regulation of both extracellular phospholipase activity and surface motility in S. marcescensIMPORTANCESerratia marcescens is known to secrete multiple extracellular enzymes, but PhlA is unusual in that this protein is thought to be exported by the flagellar transport apparatus. In this study, we demonstrate that both extracellular phospholipase activity and flagellar function are dependent on the cysteine biosynthesis pathway. Furthermore, a disruption of cysteine biosynthesis

  3. Reconstruction of totally degloved fingers: a novel application of the bilobed spiraled innervated radial artery superficial palmar branch perforator flap design provides for primary donor-site closure.

    Science.gov (United States)

    Chi, Zhenglin; Yang, Peng; Song, Dajiang; Li, Zan; Tang, Liang; Gao, Weiyang; Song, Yonghuan; Chu, Tingang

    2017-05-01

    To investigate the results of resurfacing completely degloved digits using bilobed innervated radial artery superficial palmar branch (RASPB) perforator flap in a spiral fashion. A detailed anatomic study on 30 adult fresh frozen cadavers preinjected with silicone rubber compound to demarcate arterial anatomy documented locations, numbers, and diameters of arteries and skin perforators with surrounding nerves. The flap-raising procedure was performed using four fresh cadaver specimen. We reviewed the reconstruction of 12 digits by using a bilobed spiraled innervated RASPB free perforator flap after non-replantable degloving injury. Two skin paddles were marked out using standard points of reference. At least two separate cutaneous perforator vessels were identified using a hand-held Doppler and were dissected back to the RASPB in retrograde fashion. The skin paddles were then divided between the two cutaneous perforators to provide two separate paddles with a common vascular supply. The skin paddles were stacked in a spiral fashion on the flap inset, effectively increasing the width of the flap to cover the totally degloved finger while still allowing closure of the primary donor-site. The RASPB was present within the flap in all cadavers. The direct perforator and the musculocutaneous perforator were available in 93.33 and 76.67 %, respectively, with neither of them in 6.67 % of the cases. The constantly present two perforators allowed the design of a new bilobed spiraled innervated radial artery superficial palmar branch perforator flap. We used the proposed flap to reconstruct completely degloved digits in 12 patients (mean age 28.6 years; range 17-35 years). With our proposed flap, no flap failure or re-exploration occurred and the donor site was closed primarily in all cases. All the flaps survived uneventfully. Total active motion ranged from 92° to 140° and 111° to 155° in the cases with and without metacarpophalangeal joint involvement, respectively

  4. Crystal structures of the structure-selective nuclease Mus81-Eme1 bound to flap DNA substrates

    Science.gov (United States)

    Gwon, Gwang Hyeon; Jo, Aera; Baek, Kyuwon; Jin, Kyeong Sik; Fu, Yaoyao; Lee, Jong-Bong; Kim, YoungChang; Cho, Yunje

    2014-01-01

    The Mus81-Eme1 complex is a structure-selective endonuclease with a critical role in the resolution of recombination intermediates during DNA repair after interstrand cross-links, replication fork collapse, or double-strand breaks. To explain the molecular basis of 3′ flap substrate recognition and cleavage mechanism by Mus81-Eme1, we determined crystal structures of human Mus81-Eme1 bound to various flap DNA substrates. Mus81-Eme1 undergoes gross substrate-induced conformational changes that reveal two key features: (i) a hydrophobic wedge of Mus81 that separates pre- and post-nick duplex DNA and (ii) a “5′ end binding pocket” that hosts the 5′ nicked end of post-nick DNA. These features are crucial for comprehensive protein-DNA interaction, sharp bending of the 3′ flap DNA substrate, and incision strand placement at the active site. While Mus81-Eme1 unexpectedly shares several common features with members of the 5′ flap nuclease family, the combined structural, biochemical, and biophysical analyses explain why Mus81-Eme1 preferentially cleaves 3′ flap DNA substrates with 5′ nicked ends. PMID:24733841

  5. Fundamentals of active shielding based on implicit control

    Science.gov (United States)

    Quintana, Ricardo; Lam, Yiu; Patino, Diego

    2017-11-01

    Active noise control is a methodology to attenuate low frequency noise. The attenuation is usually achieved near the sensor which is used in the controller. In order to achieve the desired attenuation inside a desired zone without locating a sensor inside, a method called active shielding can be used. It works by controlling the pressure at boundaries of the desired zone. This article presents a novel method for implementing active shielding only using pressure sensors. It is based on a new concept called implicit control, which takes into account the locations of sensors. Some simulations validate the presented method for free fields.

  6. Development of a mouse model of abdominal cutaneous flaps for breast reconstruction.

    Science.gov (United States)

    Womac, Daniel John; Palanisamy, Arun Prathap; Eslick, Rene; Schimpf, Dennis Kenneth; Chavin, Kenneth David

    2013-01-01

    Autologous tissue transfer, in addition to replacing tissue that was lost during injury or surgery, offers women an excellent option to improve cosmetic appearance and self-confidence following mastectomy due to breast cancer. However, flap necrosis is a complication in obese patients undergoing this procedure. We created a mouse model to study the flap-related complications that leads to decreased flap survival in autologous breast reconstruction. Left superficial inferior epigastric (SIE) pedicle abdominal-cutaneous flaps were elevated in 8 week-old, obese ob/ob male mice and their lean littermates. Flaps were followed by serial photography. Area of flap necrosis was measured at 7 days. Statistical analysis was performed. Necrosis was observed at the distal margin of the flaps, in both lean and obese groups. Lean left SIE flaps (n = 8) had a total area flap necrosis of 9.1% at 7 days whereas obese left SIE flaps (n = 8) had a total area flap necrosis of 45.5% at 7 days. Obese flaps had a statistically significant increase in necrosis compared to the lean flaps, p = 0.001. There was a significant difference between flap survival in lean and obese SIE pedicle flaps in our mouse model. We have developed the first flap model of obesity utilizing the superficial epigastric pedicle in the mouse. This model is optimal for future studies to dissect out mechanisms that lead to the complications related to flap survival for breast reconstruction, especially in obese subjects.

  7. The Control of Transmitted Power in an Active Isolation System

    DEFF Research Database (Denmark)

    Elliott, S.J.; Gardonio, P.; Pinnington, R.J.

    1997-01-01

    and distributed active mounts, and these models can be connected together to produce an overall theoretical description of a realistic active isolation system. Total transmitted power has been found to be an excellent criterion to quantify the effect of various control strategies in this model in which...... the contributions to the transmitted power in the various degrees of freedom can be clearly understood. It has also been found, however, that an active control system which minimises a practical estimate of transmitted power, calculated from the product of the axial forces and velocities under the mounts, can give...... of such an active vibration control system are also discussed....

  8. Controllability and hippocampal activation during pain expectation in fibromyalgia syndrome.

    Science.gov (United States)

    González-Roldán, Ana María; Bomba, Isabelle C; Diesch, Eugen; Montoya, Pedro; Flor, Herta; Kamping, Sandra

    2016-12-01

    To examine the role of perceived control in pain perception, fibromyalgia patients and healthy controls participated in a reaction time experiment under different conditions of pain controllability. No significant differences between groups were found in pain intensity and unpleasantness ratings. However, during the expectation of uncontrollable pain, patients compared to controls showed higher hippocampal activation. In addition, hippocampal activity during the pain expectation period predicted activation of the posterior cingulate cortex (PCC), precuneus and hippocampus during pain stimulation in fibromyalgia patients. The increased activation of the hippocampus during pain expectation and subsequent activation of the PCC/precuneus during the lack of control phase points towards an influence of pain perception through heightening of alertness and anxiety responses to pain in fibromyalgia patients. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Regional Myocutaneous Flaps for Head and Neck Reconstruction ...

    African Journals Online (AJOL)

    Pectoralis major and other myofascial/ myocutaneous flaps in head and neck cancer reconstruction: Experience with 437 cases at a single institution. Head Neck. 2004;26:1018-23. 13. Funk GF, Karnell LH, Whitehead S, Paulino A, Ricks J, Smith RB. Free tissue transfer versus pedicled flap cost in head and neck cancer.

  10. Revisit of Nasolabial Flap in the Reconstruction of Defects Involving ...

    African Journals Online (AJOL)

    Departments of Oral and Maxillofacial Surgery, MGV's K.B.H. Dental College, Nashik, Maharashtra, 1Manipal College of Dental Sciences, Mangalore, Karnataka, ... oral cavity defects, reconstruction, regional flaps. Address for correspondence: ..... The Arterial Anatomy of Skin Flap. New York: Churchill Livingstone; 1986. 14.

  11. Propeller flaps for lower-limb trauma | Rogers | South African ...

    African Journals Online (AJOL)

    The minor blade of the propeller may be designed to close the donor defect completely for the 180o version. The propeller flap has the advantages of local flaps (reliability, contour, texture, 'like-with-like') with additional versatility of design and donor site management, and requires minimal expertise and operative time.

  12. Breast reconstruction using a latissimus dorsi flap after mastectomy

    DEFF Research Database (Denmark)

    Højvig, Jens B; Bonde, Christian Torsten

    2015-01-01

    INTRODUCTION: The latissimus dorsi (LD) myocutaneous flap has long been regarded as the second choice flap for autologous breast reconstruction following a mastectomy in our department. Despite uncertainty about donor-site morbidity, it is regarded as a relatively safe procedure; moreover...

  13. Flap Hitching Technique to the Teeth after Oral Cancer Resection

    African Journals Online (AJOL)

    Flap Hitching Technique to the Teeth after Oral Cancer. Resection. Krishnakumar Thankappan, Subramania Iyer, Mayuri Rajapurkar, Mohit Sharma, Pramod Subash1. INTRODUCTION. Flap surgery for reconstruction is an integral part in the surgical management of head and neck tumors. After resection of the tumors of oral ...

  14. Upper lip reconstruction using a pedicel superficial temporal artery flap

    Directory of Open Access Journals (Sweden)

    Mohammad M. Al-Qattan

    2018-01-01

    Conclusion: We demonstrate that the pedicle flap is much simpler than the free flap and is adequate for reconstruction of partial upper lip defects. We also demonstrate a good cosmetic and functional outcome; and highlight several technical points to ensure a satisfactory outcome.

  15. Propeller Flap for Complex Distal Leg Reconstruction: A Versatile ...

    African Journals Online (AJOL)

    A Versatile Alternative when Reverse Sural Artery Flap is. Not Feasible. Samuel A. Ademola, Afieharo I. Michael, Femi .... flaps that were raised in the patient and the logistics of limb positioning after application of external fixators for bone ... Financial support and sponsorship. Nil. Conflicts of interest. There are no conflicts of ...

  16. Scrotal Reconstruction with a Pedicled Gracilis Muscle Flap after ...

    African Journals Online (AJOL)

    We report a case of a 34 year old African male who presented as a referral from a district hospital with a scrotal defect and exposed testes following extensive debridement of Fournier's gangrene. Scrotal reconstruction with a pedicled gracilis muscle flap was done. The pedicled gracilis muscle flap is close to the scrotal area ...

  17. Restoration of thumb sensibility with innervated reverse homodigital dorsoradial flap.

    Science.gov (United States)

    Bao, Qi Yuan; Xiao, Cheng Wei; Peng, Feng; Han, Dong; Wang, Tao; Gu, Yu Dong

    2014-01-01

    This study investigates the use of homodigital reverse dorsoradial flap with neurorrhaphy for thumb soft tissue defect. From 1996 to 2010, the homodigital dorsoradial flap was performed on seven adult patients and one 3-year-old boy. The flaps ranged from 1.2 to approximately 3.0 cm × 2.0 to approximately 4.2 cm in size. In six of the eight patients, the dorsal collateral branch of the radial nerve supplying the flap was also included in the pedicle and coapted to the proper digital nerves of the thumb. At final follow-ups, flap sensation, thumb motion, and donor-site morbidity were assessed. All flaps survived completely. At final follow-up of 8.5 months (range, 3 to 14 months), all patients except the 3-year-old child (who could not express clearly) reported satisfactory sensory recovery, with the static two-point discrimination ranging between 6 and 12 mm (mean, 9.4 mm). Range of motion of the metacarpophalangeal and interphalangeal joints of the thumbs was also preserved with minimal donor-site morbidity in all cases. Innervated reverse homodigital dorsoradial flap serves as a reliable and sensate flap for extensive thumb soft tissue reconstruction. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  18. The superiorly based bilobed flap for nasal reconstruction.

    Science.gov (United States)

    Kelly-Sell, Michael; Hollmig, S Tyler; Cook, Joel

    2018-02-01

    The laterally based bilobed flap is commonly used for the reconstruction of small- to medium-sized defects of the distal portion of the nose; However, when this flap is used to repair defects that are larger, more cephalic, or more lateral on the nose, there is a risk for lower nasal distortion. Reorienting the base superiorly preserves the advantages of the traditional design while minimizing this risk. To demonstrate the design, execution, and efficacy of the superiorly based bilobed flap. A retrospective review examined all superiorly based bilobed flaps performed by 1 surgeon (J.C.) in 2000-2016 after tumor extirpation by Mohs micrographic surgery at a single institution. A total of 41 surgical defects were closed with 40 flaps between June 2000 and August 2016 (1 patient had 2 defects closed with a single flap). Of the tumors, 55% were located on the nasal dorsum, and the median of the longest postoperative tumor axis was 1.4 cm. Follow-up was available for 40 flaps, and no infections, hematomas, or episodes of full-thickness necrosis were observed. Data were collected retrospectively from a single institution without a standardized assessment tool for aesthetic outcomes. The superiorly based bilobed flap is useful for nasal reconstruction. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  19. The use of free flaps in skull base reconstruction.

    Science.gov (United States)

    Macía, G; Picón, M; Nuñez, J; Almeida, F; Alvarez, I; Acero, J

    2016-02-01

    Skull base tumours are rare, comprising less than 1% of all tumours of the head and neck. Surgical treatment of these tumours involves the approach, the resection, and the reconstruction of the defect, which present a challenge due to the technical difficulty and anatomical complexity. A retrospective study of 17 patients with tumours involving the skull base, treated by resection and immediate reconstruction using microsurgical free flaps, is presented; 11 were men and six were women. The following types of flap were used: osteocutaneous fibula flaps, fasciocutaneous anterolateral thigh flaps, and myocutaneous latissimus dorsi flaps. The most common histology of the tumours was squamous cell carcinoma. The most frequent point of origin was the paranasal sinuses (58.8%). All of the free flaps used for reconstruction were viable. A cerebrospinal fluid fistula occurred in two patients, and in one of these cases, meningoencephalitis led to death. In conclusion, the reconstruction of large defects of the skull base after ablation requires a viable tissue that in many cases can be obtained only through the use of microvascular free flaps. The type of flap to be selected depends on the anatomical structures and size of the defect to be restored. Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. Bifurcation to forward flapping flight at intermediate Reynolds number.

    Science.gov (United States)

    Vandenberghe, Nicolas; Zhang, Jun; Childress, Stephen

    2003-11-01

    The locomotion of most fish and birds is realized by flapping wings or fins transverse to the direction of travel. According to early theoretical studies, a flapping wing translating at finite speed in an inviscid fluid experiences a propulsive force. In steady forward flight this thrust is balanced by drag. Such "lift-based mechanisms" of thrust production are characteristic of the Eulerian realm, where discrete vortical structures are shed. But, when the Reynolds number is small, viscous forces dominate and reciprocal flapping motions are ineffective. A flapping wing experiences a net drag and cannot be used to propel an organism. We have devised an experiment to bridge the two regimes, and to examine the transition to forward flight at intermediate Reynolds numbers. We study the dynamics of an horizontal wing that is flapped up and down and is free to move either forwards or backwards. This very simple kinematics emphasizes the demarcation between low and high Reynolds number because it is effective in the Eulerian realm but has no effect in the Stokesian realm. We show that flapping flight occurs abruptly as a symmetry breaking bifurcation at a critical flapping frequency. Beyond the bifurcation the forward speed increases linearly with the flapping frequency. The experiment establishes a clear demarcation between the different strategies of locomotion at large and small Reynolds number.