WorldWideScience

Sample records for active flap control

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

    Science.gov (United States)

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

    2016-09-01

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

  2. 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.

  3. Control of Flap Vortices

    Science.gov (United States)

    Greenblatt, David

    2005-01-01

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

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

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Gaunaa, Mac

    2010-01-01

    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...

  5. 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...

  6. 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 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......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...

  7. 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.

  8. 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...

  9. Stall Inception Process and Prospects for Active Hub-Flap Control in Three-Stage Axial Flow Compressor

    Institute of Scientific and Technical Information of China (English)

    Tomoya OKADA; Atsushi KAWAJIRI; Yutaka OHTA; Eisuke OUTA

    2008-01-01

    The possibility to apply the active hub-flap control method, which is a proven rotating stall control method for a single-stage compressor, to a 3-stage axial compressor is experimentally discussed, where complex rotating stall inception processes ate observed. The research compressor is a 3-stage one and could change the stagger angle settings for rotor blades and stator vanes. Sixteen rotor blade/stator vane configuration patterns were tested by changing stagger angle for the stator vanes. By measurement of surface-pressure fluctuation, stall inception proc-esses are investigated and the measured pressure fluctuation data is used as a predictive signal for rotating stall. The experimental results show that the stall detection system applied to active hub-flap control in a single-stage compressor could be usefully applied to that in a 3-stage compressor with a more complex stall inception process.

  10. 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.

  11. 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.

  12. 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.

  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. A Miniature Controllable Flapping Wing Robot

    Science.gov (United States)

    Arabagi, Veaceslav Gheorghe

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

  15. Managing Flap Vortices via Separation Control

    Science.gov (United States)

    Greenblatt, David

    2006-01-01

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

  16. 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.

  17. Flapping propulsion with tip pitch control

    Science.gov (United States)

    Huera-Huarte, Francisco; Gharib, Morteza

    2014-11-01

    The effect of flexibility in the propulsion performance and efficiency of oscillating pitching foils has received a large amount of attention in the past years. Scientists have used simplified robotic models that mimic the kinematics of flying and swimming animals, in order to get inspiration to build more efficient engineering 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 or passive control elements are also common in nature. We will show how thrust generation in a pitching fin, can be greatly affected by controlling the tip pitch motion dynamically and independently of the fin itself. This is in fact a controlled local change of curvature of the end of the fin. A robotic system has been designed in a way that not only flapping amplitudes and frequencies can be controlled, but also the amplitudes and frequencies of the tip and the phase difference between the tip and the fin. We measured thrust forces and the vortex dynamics in the near wake of the system, by using planar DPIV (Digital Particle Image Velocimetry) in a wide variety of flapping situations with tip control. Funding from Spanish Ministry of Science through Grant DPI2012-37904 is gratefully acknowledged.

  18. 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

    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......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...

  19. Management of Vortices Trailing Flapped Wings via Separation Control

    Science.gov (United States)

    Greenblatt, David

    2005-01-01

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

  20. 14 CFR 23.697 - Wing flap controls.

    Science.gov (United States)

    2010-01-01

    ... wing flap control lever settings corresponding to those positions must be positively located such that a definite change of direction of movement of the lever is necessary to select settings beyond...

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

    Science.gov (United States)

    Khodadoust, Abdollah; Washburn, Anthony

    2007-01-01

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

  2. 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...

  3. Active Aerodynamic Blade Distributed Flap Control Design Procedure for Load Reduction on the UpWind 5MW Wind Turbine

    NARCIS (Netherlands)

    Wilson, D.G.; Resor, B.R.; Berg, D.E.; Barlas, T.K.; Van Kuik, G.A.M.

    2010-01-01

    This paper develops a system identification approach and procedure that is employed for distributed control system design for large wind turbine load reduction applications. The primary goal of the study is to identify the process that can be used with multiple sensor inputs of varying types (such a

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

    DEFF Research Database (Denmark)

    Huynh, Truc; Thoft-Christensen, Palle

    This paper presents the calculation of the root mean square (RMS) response of a suspension bridge using separate control flaps (SCF) in turbulence conditions. It is assumed that the mean wind velocity is not large enough to cause coupled vibrations and that single mode buffeting response is of in......This paper presents the calculation of the root mean square (RMS) response of a suspension bridge using separate control flaps (SCF) in turbulence conditions. It is assumed that the mean wind velocity is not large enough to cause coupled vibrations and that single mode buffeting response...... on the basis of independent flutter derivatives and independent aeroelastic coefficients from the girder and from the flaps. The theory is demonstrated by a numerical example based on a long-span suspension bridge model with the Great Belt girder....

  5. ANALYSIS OF AN ELECTROSTRICTIVE STACK ACTUATORFOR ACTIVE TRAILING EDGE FLAPS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Helicopter is a complex dynamic system with many rotating components. The rotor blades operate in a highly complex aerodynamic environment. The vibratory hub load, which is caused by cyclic variation of centrifugal and aerodynamic load of the rotating blades in flight, is transmitted to the fuselage, resulting in serious vibration and noise of the structure. It is one of the most important exciting sources in helicopters.  There has long been a desire to reduce helicopter vibration and to improve its performance. Control schemes adopted so far can be classified as either passive or active control technologies. The passive technologies include optimization of rotor hub, blade and the fuselage, hub or blade mounted passive vibration absorbers and anti-resonant vibration isolators. One of the major disadvantages with passive technologies is that they are designed to provide maximum vibration reduction at a specific frequency; therefore, their performance is degraded significantly with changes in the operating conditions of the rotor system.  With the development of computer science and active control technology, increasing efforts have been devoted to active control technologies to benefit helicopter vibration suppression in recent years. Earlier studies include Higher Harmonic Control (HHC)[1] and Individual Blade Control (IBC)[2], which is aimed to reduce the vibratory blade load by oscillating the blade in pitch motion using hydraulic actuators. It is successful in suppressing the vibration of the fuselage; however, its application is limited by serious energy consumption.  To overcome these difficulties, a new concept in helicopter vibration control is the smart rotor system. In this scheme, actuators are embedded in composite blades. They are used to activate the trailing edge flaps in higher harmonic pitch motion to adjust the lift force actively. Under the regulation of a control system, the vibratory hub load can be counteracted actively at

  6. 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...

  7. The Effect of the Active Ingredient Thymoquinone on Flap Viability in Random Pattern Flaps in Rats.

    Science.gov (United States)

    Kocak, Omer Faruk; Bozan, Nazim; Oksuz, Mustafa; Yuce, Serdar; Demir, Canser Yılmaz; Bulut, Gulay; Ragbetli, Murat Cetin

    2016-08-01

    Thymoquinone (TQ) is a plant extract that has been shown to have antioxidant, anti-inflammatory, angiogenic, antimicrobial, and anticarcinogenic effects. The aim of this study is to research how the use of TQ affects flap viability. 42 rats were placed into 6 groups, with 7 rats in each. A 3 × 10 cm McFarlane flap model was used on the test animals. The sham group had used neither surgical nor TQ treatment. The control group had surgery but no treatment afterwards. The preoperative TQ group was given oral doses of 2 mg/kg. TQ for 10 days preoperatively with no treatment after the surgical procedure. The postoperative TQ group received oral doses of 2 mg/kg TQ for 10 days after the surgical process. The preoperative + postoperative (pre + postoperative) TQ group was given oral doses of 2 mg/kg TQ for 10 days both preoperatively and postoperatively. Finally, the dimethylsulfoxide group received 10 mg/kg dimethylsulfoxide (DMSO) for 10 days both preoperatively and postoperatively. Ten days after surgery the findings were evaluated. The average rates of necrosis were found to be 29.7 % in the control group, 19.18 % in the preoperative TQ group, 13.05 % in the postoperative TQ group, 8.42 % in the pre + postoperative TQ group, and 29.03 % in the DMSO group. The experimental groups had better area measurement, histopathological, and electron microscopic results than the control group (All; p < 0.05). We believe that, because of its antioxidant, anti-inflammatory, and angiogenic properties, thymoquinone is an agent that can prevent ischemia-reperfusion damage and, therefore, prevent necrosis. PMID:27072137

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

    DEFF Research Database (Denmark)

    Castaignet, Damien Bruno

    with three trailing edge flaps on one blade, located on DTU’s Risø Campus in Roskilde, Denmark. This thesis is divided into three parts: the controller design, results from simulations, and results from the experiments. The trailing edge flaps controller designed for this project is based on a frequency......, in Roskilde, Denmark. One blade of the turbine was equipped with three independent trailing edge flaps. In spite of the failure of several sensors and actuators, the test of the trailing edge flaps controller described in this thesis showed a consistent flapwise blade root fatigue load reduction. An average...

  9. 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.

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

    DEFF Research Database (Denmark)

    Bergami, Leonardo

    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......-MPC requires lower flap activity, and also achieves higher reductions of the tower fatigue loads, thus indicating that a combined control approach that coordinates and integrates all available sensors and actuators has the potential for overall better results than achieved by a series of independent control...

  11. 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......-based controller. The combined control approach allow to achieve higher load alleviations, furthermore, in the presence of e.g. deterioration of an actuator, it enables an online re-tuning of the workload distribution of blade pitch and trailing edge flaps, thus potentially increasing the smart rotor reliability....

  12. 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......-based controller. The combined control approach allow to achieve higher load alleviations, furthermore, in the presence of e.g. deterioration of an actuator, it enables an online re-tuning of the workload distribution of blade pitch and trailing edge flaps, thus potentially increasing the smart rotor reliability....

  13. 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...... structures, we determined factors essential for the thermodynamic stability of EXO1. We show that enzymatic activity and stability of EXO1 on DNA is modulated by temperature. By characterization of EXO1 flap activity using various DNA flap substrates, we show that EXO1 has a strong capacity for degrading...... double stranded DNA and has a modest endonuclease or 5' flap activity. Furthermore, we report novel mechanistic insights into the processing of flap structures, showing that EXO1 preferentially cleaves one nucleotide inwards in a double stranded region of a forked and nicked DNA flap substrates...

  14. Passive control of a dynamically pitching wind turbine airfoil under aeroelastic conditions using a Gurney flap

    Science.gov (United States)

    Nikoueeyan, Pourya; Magstadt, Andrew; Strike, John; Hind, Michael; Naughton, Jonathan

    2014-11-01

    To reduce the cost of energy, wind turbine design has moved towards larger blades that are heavier and have lower relative structural stiffness compared to shorter blades. To address the lower blade stiffness, different flow control techniques have been considered. The Gurney flap, a small, low-cost and effective control method, is a promising control actuator. Wind tunnel testing has been performed on a DU97-W-300 10% flatback airfoil undergoing dynamic pitching relevant to flow conditions encountered by wind turbine blades. To mimic blade compliance, the airfoil is actively driven through a torsionally elastic element. Time-resolved surface pressure measurements have been acquired from which lift Cl and moment Cm coefficients were calculated. Changes in Cl and Cm in moderate and deep dynamic stall regimes for different Gurney flap heights were studied for different pitch drive conditions (amplitude and frequency). The results show the significant impact of compliance on the angle of attack (α) range experienced by the airfoil. Shifts in α range result in different hysteresis behavior in both Cl and Cm and demonstrate the effectiveness of the Gurney flap in modifying the aerodynamics of wind turbine blades experiencing dynamic pitching. This work supported by DOE and a gift from BP.

  15. 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

  16. Enhanced Correlation of SMART Active Flap Rotor Loads

    Science.gov (United States)

    Kottapalli, Sesi

    2011-01-01

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

  17. 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.

  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...... of the rotor through modification of unsteady aerodynamic loads. Piezoelectric actuators installed inside the blade manipulate the motion of the trailing edge flap. The proposed blade rotates at higher speed and additional structures are included to support the actuators and the flap. This improves the design....... 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...

  19. Development of Air Vehicle with Active Flapping and Twisting of Wing

    Institute of Scientific and Technical Information of China (English)

    Sangyol Yoon; Lae-Hyong Kang; Sungho Jo

    2011-01-01

    This paper addresses mechanisms for active flapping and twisting of robotic wings and assesses flying effectiveness as a function of twist angle. Unlike the flapping motion of bird wings, insects generally make a twisting motion at the root of their wings while flapping, which makes it possible for them to hover in midair. This work includes the development of a Voice Coil Motor (VCM) because a flapping-wing air vehicle should be assembled with a compact actuator to decrease size and weight. A linkage mechanism is proposed to transform the linear motion of the VCM into the flapping and twisting motions of wings. The assembled flapping-wing air vehicle, whose weight is 2.86 g, produces an average positive vertical force proportional to the twist angle. The force saturates because the twist angle is mechanically limited. This work demonstrates the possibility of developing a flapping-wing air vehicle that can hover in midair using a mechanism that actively twists the roots of wings during flapping.

  20. 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

  1. 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

    . In this study, a comparison between aerodynamic predictions of the aeroelastic code HAWC2 and the Navier-Stokes code EllipSys3D for the NREL 5MW reference wind turbine rotor in a stiff configuration equipped with a deformable trailing edge flap is performed. A case where the half rotor plane experiences......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...... an inflow resembling the wake from an upstream wind turbine is investigated, which is appropriate for comparing the predictions of the two codes related to the abrupt aerodynamic response and the influence of the controllable flap. The trailing edge flap is actuated to alleviate the added loads from a non...

  2. Effectiveness of Boundary-layer Control, Obtained by Blowing over a Plain Rear Flap in Combination with a Forward Slotted Flap, in Deflecting a Slipstream Downward for Vertical Take-off

    Science.gov (United States)

    Spreemann, Kenneth P

    1958-01-01

    The wing employed in this investigation had a 67-percent-chord slotted flap in combination with a 33-percent-chord plain rear flap equipped with a full-span blowing nozzle. The tests were conducted in a static-thrust facility at the Langley Aeronautical Laboratory. The investigation indicated that the plain rear flap alone with a low momentum coefficient for boundary-layer control provided larger turning angles than the combined slotted and plain flaps without boundary-layer control.

  3. Effects of leading-edge flap oscillation on unsteady delta wing flow and rock control

    Science.gov (United States)

    Kandil, Osama A.; Salman, Ahmed A.

    1991-01-01

    The isolated and interdisciplinary problems of unsteady fluid dynamics and rigid-body dynamics and control of delta wings with and without leading-edge flap oscillation are considered. For the fluid dynamics problem, the unsteady, compressible, thin-layer Navier-Stokes (NS) equations, which are written relative to a moving frame of reference, are solved along with the unsteady, linearized, Navier-displacement (ND) equations. The NS equations are solved for the flowfield using an implicit finite-volume scheme. The ND equations are solved for the grid deformation, if the leading-edge flaps oscillate, using an ADI scheme. For the dynamics and control problem, the Euler equation of rigid-body rolling motion for a wing and its flaps are solved interactively with the fluid dynamics equations for the wing-rock motion and subsequently for its control. A four-stage Runge-Kutta scheme is used to explicitly integrate the dynamics equation.

  4. 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...... compared with a real bridge. Five flap configurations are investigated during the wind tunnel experiments and depending on the actual flap configuration it is possible to decrease or increase the flutter wind velocity for the model....

  5. 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...... on the blade root. The design model is based on a modal model of the blade structure and a steady state aerodynamic model of the blade airfoils. Depending on the output filter, loads within different frequency range are decreased. A fine tuning of the Kalman filter and of the cost function allows to decrease...... significantly the blade root loads without damaging excessively the trailing edge flap actuators....

  6. 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...... in conditions with strong wind shear. The demands for the flap actuator in terms of deflection angles was ±10°. The requirements in terms of the flap deflection velocity depend mainly on the inflow turbulence intensity. The maximum value was±40°s-1 for 20% inflow turbulence intensity. Unsteady aerodynamic...... effects seem to be negligible. Copyright © 2015 John Wiley & Sons, Ltd....

  7. 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...... at various radial positions on the blade is investigated. An optimization routine minimizes blade root fatigue loads. Calculations are based on the 5 MW reference wind turbine part of the UpWind project primarily with a mean turbulent wind speed close to rated power. A fatigue load reduction of 25...

  8. 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

    vanes placed in front of the main test wing. These were situated symmetrically above and below the airfoil in a way that created a fast turning of the air flow without directly affecting the boundary layer on the test airfoil. The Reynolds number was Re=500.000. The PID-controlled flap was able...

  9. 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 several state-of-the art simulation codes, allowing for a wide variety of problem formulations and combinations of models. A simultaneous aerodynamic and structural optimization of a 10 MW wind turbine rotor is carried out with respect to material layups and outer shape. Active trailing edge flaps...... are integrated in the design taking into account their achieved fatigue load reduction. The optimized ‘smart blade’ design is compared to an aeroelastically optimized design with no flaps and the baseline design....

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

    Science.gov (United States)

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

    2015-09-01

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

  11. Aeroservoelastic Pitch Control of Stall-Induced Flap/Lag Flutter of Wind Turbine Blade Section

    Directory of Open Access Journals (Sweden)

    Tingrui Liu

    2015-01-01

    Full Text Available The aim of this paper is to analyze aeroelastic stability, especially flutter suppression for aeroelastic instability. Effects of aeroservoelastic pitch control for flutter suppression on wind turbine blade section subjected to combined flap and lag motions are rarely studied. The work is dedicated to solving destructive flapwise and edgewise instability of stall-induced flutter of wind turbine blade by aeroservoelastic pitch control. The aeroelastic governing equations combine a flap/lag structural model and an unsteady nonlinear aerodynamic model. The nonlinear resulting equations are linearized by small perturbation about the equilibrium point. The instability characteristics of stall-induced flap/lag flutter are investigated. Pitch actuator is described by a second-order model. The aeroservoelastic control is analyzed by three types of optimal PID controllers, two types of fuzzy PID controllers, and neural network PID controllers. The fuzzy controllers are developed based on Sugeno model and intuition method with good results achieved. A single neuron PID control strategy with improved Hebb learning algorithm and a radial basic function neural network PID algorithm are applied and performed well in the range of extreme wind speeds.

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

    NARCIS (Netherlands)

    Loendersloot, R.; 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 em

  13. 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.

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

    Science.gov (United States)

    Kottapalli, Sesi; Leyland, Jane

    2014-01-01

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

  15. Axial flow effects on robustness of vortical structures about actively deflected wings in flapping flight

    Science.gov (United States)

    Medina, Albert; Kweon, Jihoon; Choi, Haecheon; Eldredge, Jeff D.

    2012-11-01

    Flapping wing flight has garnered much attention in the past decade driven by our desire to understand capabilities observed in nature and to develop agile small-scale aerial vehicles. Nature has demonstrated the breadth of maneuverability achievable by flapping wing flight. However, despite recent advances the role of wing flexibility remains poorly understood. In an effort to develop a deeper understanding of wing deflection effects and to explore novel approaches to increasing leading-edge vortex robustness, this three-dimensional computational study explores the aerodynamics of low aspect ratio plates, in hovering kinematics, with isolated flexion lines undergoing prescribed deflection. Major flexion lines, recognized as the primary avenue for deflection in biological fliers, are isolated here in two distinct configurations, resulting in deflection about the wing root and the wing tip, respectively. Of interest is the interaction between axial flow along the span and the vortical structures about the wing. It is proposed that the modes of deflection explored may provide a means of axial flow control for favorably promoting LEV robustness over a broad range of flapping conditions, and provide insight into the nature of flexibility in flapping wing flight. National Science Foundation, National Research Foundation of Korea.

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

    OpenAIRE

    Freire Gomez, Jon; Booker, Julian D; Mellor, Phil

    2015-01-01

    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 ove...

  17. 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

  18. 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.

  19. Active Pedicle Epithelial Flap Transposition Combined with Amniotic Membrane Transplantation for Treatment of Nonhealing Corneal Ulcers

    Directory of Open Access Journals (Sweden)

    Ting Zhang

    2016-01-01

    Full Text Available Introduction. The objective was to evaluate the efficacy of active pedicle epithelial flap transposition combined with amniotic membrane transplantation (AMT in treating nonhealing corneal ulcers. Material and Methods. Eleven patients (11 eyes with nonhealing corneal ulcer who underwent the combined surgery were included. Postoperatively, ulcer healing time was detected by corneal fluorescein staining. Visual acuity, intraocular pressure, surgical complications, and recurrence were recorded. Corneal status was inspected by the laser scanning confocal microscopy and anterior segment optical coherence tomography (AS-OCT. Results. The primary diseases were herpes simplex keratitis (8 eyes, corneal graft ulcer (2 eyes, and Stevens-Johnson syndrome (1 eye. All epithelial flaps were intact following surgery, without shedding or displacement. Mean ulcer healing time was 10.8±3.1 days, with a healing rate of 91%. Vision significantly improved from 1.70 to 0.82 log MAR (P=0.001. A significant decrease in inflammatory cell infiltration and corneal stromal edema was revealed 2 months postoperatively by confocal microscopy and AS-OCT. Corneal ulcer recurred in 1 eye. None of the patients developed major complications. Conclusion. Active pedicle epithelial flap transposition combined with AMT is a simple and effective treatment for nonhealing corneal ulcers.

  20. Continuous Trailing-Edge Flaps for Primary Flight Control of a Helicopter Main Rotor

    Science.gov (United States)

    Thornburgh, Robert P.; Kreshock, Andrew R.; Wilbur, Matthew L.; Sekula, Martin K.; Shen, Jinwei

    2014-01-01

    The use of continuous trailing-edge flaps (CTEFs) for primary flight control of a helicopter main rotor is studied. A practical, optimized bimorph design with Macro-Fiber Composite actuators is developed for CTEF control, and a coupled structures and computational fluid dynamics methodology is used to study the fundamental behavior of an airfoil with CTEFs. These results are used within a comprehensive rotorcraft analysis model to study the control authority requirements of the CTEFs when utilized for primary flight control of a utility class helicopter. A study of the effect of blade root pitch index (RPI) on CTEF control authority is conducted, and the impact of structural and aerodynamic model complexity on the comprehensive analysis results is presented. The results show that primary flight control using CTEFs is promising; however, a more viable option may include the control of blade RPI, as well.

  1. 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...

  2. A flow control mechanism in wing flapping with stroke asymmetry during insect forward flight

    Institute of Scientific and Technical Information of China (English)

    Yongliang Yu; Binggang Tong

    2005-01-01

    A theoretical modeling approach as well as an unsteady analytical method is used to study aerodynamic characteristics of wing flapping with asymmetric stroke-cycles in connection with an oblique stroke plane during insect forward flight. It is revealed that the aerodynamic asymmetry between the downstroke and the upstroke due to stroke-asymmetrical flapping is a key to understand the flow physics of generation and modulation of the lift and the thrust. Predicted results for examples of given kinematics validate more specifically some viewpoints that the wing lift is more easily produced when the forward speed is higher and the thrust is harder, and the lift and the thrust are generated mainly during downstroke and upstroke, respectively. The effects of three controlling parameters, i.e. the angles of tilted stroke plane,the different downstroke duration ratios, and the different angles of attack in both down- and up-stroke, are further discussed. It is found that larger oblique angles of stroke planes generate larger thrust but smaller lift; larger downstroke duration ratios lead to larger thrust, while making little change in lift and input aerodynamic power; and again, a small increase of the angle of attack in downstroke or upstroke may cause remarkable changes in aerodynamic performance in the relevant stroke.

  3. Effectiveness Using Circular Fibre Steel Flap Gate As a Control Structure Towards the Hydraulic Characteristics in Open Channel

    Science.gov (United States)

    Adib, M. R. M.; Amirza, A. R. M.; Wardah, T.; Junaidah, A.

    2016-07-01

    Hydraulic control gate structure plays an important role in regulating the flow of water in river, canal or water reservoir. One of the most appropriate structures in term of resolving the problem of flood occured is the construction of circular fibre steel flap gate. Therefore, an experiment has been conducted by using an open channel model at laboratory. In this case, hydraulic jump and backwater were the method to determined the hydraulic characteristics of circular fibre steel flap gate in an open channel model. From the experiment, the opening angle of flap gate can receive discharges with the highest flow rate of 0.035 m3/s with opening angle was 47°. The type of jump that occurs at the slope of 1/200 for a distance of 5.0 m is a standing jump or undulating wave. The height of the backwater can be identified based on the differences of specific force which is specific force before jump, F1 and specific force after jump, F2 from the formation of backwater. Based on the research conducted, the tendency of incident backwater wave occurred was high in every distance of water control location from water inlet is flap slope and the slope of 1/300 which is 0.84 m/s and 0.75 m/s of celerity in open channel model.

  4. High-Lift System for a Supercritical Airfoil: Simplified by Active Flow Control

    Science.gov (United States)

    Melton, LaTunia Pack; Schaeffler, Norman W.; Lin, John C.

    2007-01-01

    Active flow control wind tunnel experiments were conducted in the NASA Langley Low-Turbulence Pressure Tunnel using a two-dimensional supercritical high-lift airfoil with a 15% chord hinged leading-edge flap and a 25% chord hinged trailing-edge flap. This paper focuses on the application of zero-net-mass-flux periodic excitation near the airfoil trailing edge flap shoulder at a Mach number of 0.1 and chord Reynolds numbers of 1.2 x 10(exp 6) to 9 x 10(exp 6) with leading- and trailing-edge flap deflections of 25 deg. and 30 deg., respectively. The purpose of the investigation was to increase the zero-net-mass-flux options for controlling trailing edge flap separation by using a larger model than used on the low Reynolds number version of this model and to investigate the effect of flow control at higher Reynolds numbers. Static and dynamic surface pressures and wake pressures were acquired to determine the effects of flow control on airfoil performance. Active flow control was applied both upstream of the trailing edge flap and immediately downstream of the trailing edge flap shoulder and the effects of Reynolds number, excitation frequency and amplitude are presented. The excitations around the trailing edge flap are then combined to control trailing edge flap separation. The combination of two closely spaced actuators around the trailing-edge flap knee was shown to increase the lift produced by an individual actuator. The phase sensitivity between two closely spaced actuators seen at low Reynolds number is confirmed at higher Reynolds numbers. The momentum input required to completely control flow separation on the configuration was larger than that available from the actuators used.

  5. ANALYSIS OF AN ELECTROSTRICTIVE STACK ACTUATOR FOR ACTIVE TRAILING EDGE FLAPS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Stack actuator is a solid-state driving component of Active Tailing Edge Flap in smart rotor systems. It is a multi-layer serial structure of basic units composed of electrostrictive and adhesive layers. In this paper, a dynamic model of the actuator is derived based on the constitutive equation of electrostrictive material and the equation of motion. Theoretical analysis is made on the factors involved in the design of the actuator, which reveals that the electrostrictive layer and the adhesive layer should be optimized to compromise between displacement and frequency requirements. In the final part of the paper, the experiment of an ATEF system is introduced. The results show that the model is reasonable. It also suggests that the bending stiffness of elastic mechanism is an important factor in design, which should be carefully studied to provide satisfactory dynamic response of the ATEF system.

  6. Single-Point Remote Control of Flapping Motion in Clothespin-Shaped Bimetallic Palladium Complexes Based on the N(sp(2) )-N(sp(3) ) Interconversion in Amide Functionalities.

    Science.gov (United States)

    Inoue, Ryo; Kawamorita, Soichiro; Naota, Takeshi

    2016-04-11

    The synthesis, structure, and flapping motion of clothespin-shaped binuclear trans-bis(salicylaldiminato)palladium(II) complexes (anti-1) with 4-azaheptamethylene linkers bearing amide (a-g), urethane (h), or urea (i) functionalities are described in this report. Various 2D (1) H NMR experiments and XRD analyses indicate that the amide- and urethane-linked anti-1 a,b,d-h complexes exist as equilibrated mixtures of major and minor conformers I and II in CDCl3 , whereas the complexes anti-1 c and i were observed as a single species. The mapping of NOESY cross-peaks between conformers I and II revealed that the equilibration of the major and minor conformers of anti-1 a,b,d-h proceeds by two pathways, namely a nonrotatory flapping motion of the coordinated blades and a nonflapping rotation of C-N bonds, whereas the equilibration of anti-1 c proceeds by simultaneous flapping and rotation motions. Kinetic studies carried out by means of (1) H-(1) H EXSY experiments revealed that 1) the ΔG(≠) 298K values for the flapping motion are controlled remotely by the steric and electronic effects of the RCON functionalities and 2) the activation parameters for the nonrotatory flapping process are identical to those for the nonflapping peptide rotation in the complexes anti-1 a,b,d-h, which indicates that the present multistep conformational transformation induced by the flapping motion is controlled by the rate-determining pyramidalization/depyramidalization (i.e., sp(2) /sp(3) interconversion) of the nitrogen atoms of the functionalities. The static and controllable molecular mobility of anti-1 bearing peptide linkers has been discussed by comparison with the dynamic behavior of its analogues anti-2-4 with flexible polymethylene linkers. PMID:26934178

  7. Control of flight forces and moments by flapping wings of model bumblebee

    Institute of Scientific and Technical Information of China (English)

    WU Jiang-hao; SUN Mao

    2008-01-01

    The control of flight forces and moments by flapping wings of a model bumblebee is studied using the method of computational fluid dynamics.Hovering flight is taken as the reference flight:Wing kinematic parameters are varied with respect to their values at hovering flight.Moments about(and forces along)x,y,z axes that pass the center of mass are computed.Changing stroke amplitude(or wingbeat frequency)mainly produces a vertical force.Changing mean stroke angle mainly produces a pitch moment.Changing wing angle of attack,when down-and upstrokes have equal change,mainly produces a vertical force,while when down-and upstrokes have opposite changes,mainly produces a horizontal force and a pitch moment.Changing wing rotation timing,when dorsal and ventral rotations have the same timing,mainly produces a vertical force,while when dorsal and ventral rotations have opposite timings,mainly produces a pitch moment and a horizontal force.Changing rotation duration has very small effect on forces and moments.Anti-symmetrically changing stroke amplitude(or wingbeat frequency)of the contralateral wings mainly produces a roll moment.Anti-symmetrically changing angles of attack of the contralateral wings,when down-and upstrokes have equal change,mainly produces a roll moment,while when down-and upstrokes have opposite changes,mainly produces a yaw moment.Anti-symmetrically changing wing rotation timing of the contralateral wings,when dorsal and ventral rotations have the same timing,mainly produces a roll moment and a side force,while when dorsal and ventral rotations have opposite timings,mainly produces a yaw moment.Vertical force and moments about the three axes can be separately controlled by separate kinematic variables.A very fast rotation can be achieved with moderate changes in wing kinematics.

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

    Science.gov (United States)

    Kottapalli, Sesi B. R.

    2010-01-01

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

  9. Active control for performance enhancement of electrically controlled rotor

    Institute of Scientific and Technical Information of China (English)

    Lu Yang; Wang Chao

    2015-01-01

    Electrically controlled rotor (ECR) system has the potential to enhance the rotor perfor-mance 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 perfor-mance 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.

  10. 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.

  11. 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.

  12. Retrospective study of reverse dorsal metacarpal flap and compound flap: a review of 122 cases

    Institute of Scientific and Technical Information of China (English)

    LU Lai-jin; GONG Xu; LIU Zhi-gang; ZHANG Zhi-xin

    2006-01-01

    Objective:To evaluate the clinical application and discuss the operative indication of the reverse dorsal metacarpal flap and its compound flap on the skin defects of hand.Methods: From 1990 to 2003, we applied the reverse dorsal metacarpal flap and its compound flap to repair soft tissue defects of fingers in 122 cases, which included 90cases of the reverse metacarpal flap and 32 cases of its compound flaps with tendon grafts, nerve grafts or bone grafts. Based on the follow-up observations, we analyzed the indications of the reverse metacarpal flap and its compound flaps, the postoperative contours, flap colors and textures in comparison to contralateral fingers retrospectively.Results: In the series of 122 cases, flaps survived and the donor site defects were closed directly. The follow-up period ranged from 1-12 years. The postoperative contours,colors and textures of the flaps and its compound flaps were similar to those of normal fingers, although linear scar remained. According to standards of sense recovery(British Medical Research Council, BMRC ), the sense function of the flaps resumed S3 after operation for 1 year.In 10 cases with the tendon defects treated by the flap with tendon grafts, function of flexion-extension of fingers resumed 50%-75% in comparison to the contralateral fingers using the method of measurement of total active motion. In 7 cases with the phalangeal nonunion or bone defects treated by the flap with bone grafts, union occurred after operation for 3 months.Conclusions: To soft tissue defects on fingers with bone or tendon exposure, the reverse metacarpal flap and its compound flap are a better choice for repairing. The range of repairing is up to the distal interphalangeal joint of fingers. The second dorsal metacarpal artery is more consistent and larger as the choice of vascular pedicle, in comparison with other dorsal metacarpal arteries.Postoperative flap color and texture are similar to normal fingers.

  13. Wind tunnel test on airfoil Riso-B1-18 with an Active Trailing Edge Flap

    DEFF Research Database (Denmark)

    Bak, Christian; Gaunaa, Mac; Andersen, Peter Bjørn;

    2010-01-01

    A wind tunnel test of the wind turbine airfoil Risø-B1-18 equipped with an Active Trailing Edge Flap (ATEF) was carried out. The ATEF was 9% of the total chord, made of piezo electric actuators attached to the trailing edge of a non-deformable airfoil and actuated using an (electric) amplifier....... The airfoil was tested at Re = 1.66 × 106. Steady state and dynamic tests were carried out with prescribed deflections of the ATEF. The steady state tests showed that deflecting the ATEF towards the pressure side (positive ) translated the lift curve to higher lift values and deflecting the ATEF towards...

  14. Fasciocutaneous flaps

    NARCIS (Netherlands)

    D.E. Tolhurst (David)

    1988-01-01

    textabstractAbout that time the concept of independent myocutaneous vascular territories (Me Craw and Dibbell, 1977) was beginning to take hold but the deep fascia, sandwiched between muscles and the skin, was largely regarded as an isolating layer of dense, avascular fibrous tissue from which flaps

  15. 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)

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

    OpenAIRE

    Bergami, Leonardo; Gaunaa, Mac; Poulsen, Niels Kjølstad; Buhl, Thomas

    2013-01-01

    Denne afhandling omhandler udviklingen af et aktivt smart rotor koncept fra et aeroservoelastisk perspektiv. En aktiv smart rotor er en vindmøllerotor som igennem en kombination af sensorer, reguleringsenhed og aktuatorer, aktivt kan reducere den fluktuerende del af de aerodynamiske kræfter møllen skal modstå. Undersøgelsen omhandler en specifik aktuator type: Adaptive Trailing Edge Flap (ATEF), der består af en kontinuert deformation af den bagerste del af vingeprofilernes tværsnitsform.Der ...

  17. 4,5-Diarylisoxazol-3-carboxylic acids: A new class of leukotriene biosynthesis inhibitors potentially targeting 5-lipoxygenase-activating protein (FLAP).

    Science.gov (United States)

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

    2016-05-01

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

  18. Effects of torsion frequencies on rotor performance and structural loads with trailing edge flap

    International Nuclear Information System (INIS)

    The effects of variation of blade torsion frequency on rotor performance and structural loads are investigated for a 1/rev active flap rotor and baseline rotor (no active control). The UH-60A four-bladed articulated main rotor is studied at a high-speed forward flight condition. The torsion frequencies are varied by modifying the spanwise torsional stiffness of the blade and/or the pitch link stiffness. First, a parametric/optimization study on the flap deployment schedule is carried out using lifting-line comprehensive analysis for the soft, baseline, and stiff rotor configurations, and then a higher fidelity coupled computational fluid dynamics–computational structural dynamics analysis is carried out for the optimal flap deployment. It is shown that with the soft rotor there is degradation in performance—of about 6% with respect to the baseline rotor in the case where the flaps are not activated, and of about 1% if flap deflections are applied. On the other hand, for the stiff rotor there is a slight improvement in performance of about 2.3% when the flaps are not activated, and no appreciable change in the case where active flap deflections are applied. It appears that the peak performance achievable with using active flaps on a baseline stiffness rotor cannot be further improved significantly by varying the torsional frequencies. Variation of torsion frequency does not appear to have a significant influence on blade torsion moments and pitch link loads, although the 1/rev flap activation examined has an important role. (paper)

  19. 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...

  20. Coronally Advanced Flap with Different Designs in the Treatment of Gingival Recession: A Comparative Controlled Randomized Clinical Trial.

    Science.gov (United States)

    Zucchelli, Giovanni; Stefanini, M; Ganz, S; Mazzotti, Claudio; Mounssif, Ilham; Marzadori, Matteo

    2016-01-01

    The aim of this parallel double-blind randomized controlled clinical trial was to describe a modified approach using the coronally advanced flap (CAF) with triangular design and to compare its efficacy, in terms of root coverage and esthetics, with a trapezoidal type of CAF. A sample of 50 isolated Miller Class I and II gingival recessions with at least 1 mm of keratinized tissue apical to the defects were treated with CAF. Of these recessions, 25 were randomly treated with trapezoidal CAF (control group) while the other 25 (test group) were treated with a modified triangular CAF. The clinical and esthetic evaluations, made by the patient and an independent periodontist, were performed 3 months, 6 months, and 1 year after the surgery. No statistically significant difference was demonstrated between the two CAF groups in terms of recession reduction, complete root coverage, or 6-month and 1-year patient esthetic scores. Better 3-month patient esthetic evaluations and better periodontist root coverage, color match, and contiguity assessments were reported after triangular CAF. Trapezoidal CAF was associated with greater incidence of keloid formation. Single-type gingival recessions can be successfully covered with both types of CAF. The triangular CAF should be preferred for esthetically demanding patients. PMID:27100801

  1. Effects of Bezafibrate on the Survival of Random Skin Flaps in Rats.

    Science.gov (United States)

    Lin, Bin; Lin, Yuting; Lin, Dingsheng; Cao, Bin

    2016-06-01

    Background Bezafibrate is widely used in clinics for its comparable angiogenic effect. Our research is to investigate the effect of bezafibrate on random skin flap survival. Materials and Methods The "McFarlane flap" rat models were established in 30 male Sprague-Dawley rats which were divided into two groups. The treatment group was given bezafibrate (400 mg/kg/day; gavage administration), and the control group received the vehicle. The flap surviving area was measured after 7 days, and the tissue samples were taken for histological analysis and edema measurement. Vascular endothelial growth factor (VEGF) was determined using immunohistochemical methods. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were examined with kits. Results Seven days after the operation, the surviving area in the treatment group was larger than in the control group (p Bezafibrate improves the survival of random skin flaps effectively. PMID:26872027

  2. Engineered Vascularized Muscle Flap.

    Science.gov (United States)

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

    2016-01-01

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

  3. 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...

  4. An Improved Evolvable Oscillator and Basis Function Set for Control of an Insect-Scale Flapping-Wing Micro Air Vehicle

    Institute of Scientific and Technical Information of China (English)

    John C.Gallagher; Michael W.Oppenheimer

    2012-01-01

    This paper introduces an improved evolvable and adaptive hardware oscillator design capable of supporting adaptation intended to restore control precision in damaged or imperfectly manufactured insect-scale flapping-wing micro air vehicles.It will also present preliminary experimental results demonstrating that previously used basis function sets may have been too large and that significantly improved learning times may be achieved by judiciously culling the oscillator search space.The paper will conclude with a discussion of the application of this adaptive,evolvable oscillator to full vehicle control as well as the consideration of longer term goals and requirements.

  5. Micro Aerial Vehicle (MAV Flapping Motion Control Using an Immune Network with Different Immune Factors

    Directory of Open Access Journals (Sweden)

    Liguo Weng

    2013-08-01

    Full Text Available This paper proposes a novel Neural‐Immunology/Memory Network to address the problem of motion control for flapping‐wing Micro Aerial Vehicles (MAVs. This network is inspired by the human memory system as well as the immune system, and it is effective in attenuating the system errors and other lumped system uncertainties. In contrast to most existing Neural Networks, the convergence of this proposed Neural‐Immunology/Memory Network can be theoretically proven. Both analyses and simulations that are based on different immune factors show that the proposed control method is effective in dealing with external disturbances, system nonlinearities, uncertainties and parameter variations.

  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 co

  7. 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...... in an open jet wind tunnel shows promising results. In the wind tunnel, it is possible to regulate the wind speed as well as turn the blade profile to simulate a change in wind direction in relation to the profile....

  8. Advanced Load Alleviation for Wind Turbines using Adaptive Trailing Edge Flaps: Sensoring and Control

    DEFF Research Database (Denmark)

    Andersen, Peter Bjørn

    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...

  9. 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

    2016-04-01

    Human flap endonuclease-1 (hFEN1) catalyzes the essential removal of single-stranded flaps arising at DNA junctions during replication and repair processes. hFEN1 biological function must be precisely controlled, and consequently, the protein relies on a combination of protein and substrate conformational changes as a prerequisite for reaction. These include substrate bending at the duplex-duplex junction and transfer of unpaired reacting duplex end into the active site. When present, 5'-flaps are thought to thread under the helical cap, limiting reaction to flaps with free 5'-terminiin vivo Here we monitored DNA bending by FRET and DNA unpairing using 2-aminopurine exciton pair CD to determine the DNA and protein requirements for these substrate conformational changes. Binding of DNA to hFEN1 in a bent conformation occurred independently of 5'-flap accommodation and did not require active site metal ions or the presence of conserved active site residues. More stringent requirements exist for transfer of the substrate to the active site. Placement of the scissile phosphate diester in the active site required the presence of divalent metal ions, a free 5'-flap (if present), a Watson-Crick base pair at the terminus of the reacting duplex, and the intact secondary structure of the enzyme helical cap. Optimal positioning of the scissile phosphate additionally required active site conserved residues Tyr(40), Asp(181), and Arg(100)and a reacting duplex 5'-phosphate. These studies suggest a FEN1 reaction mechanism where junctions are bound and 5'-flaps are threaded (when present), and finally the substrate is transferred onto active site metals initiating cleavage.

  10. 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

  11. 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...

  12. The platysma myocutaneous flap.

    Science.gov (United States)

    Baur, Dale A; Williams, Jonathan; Alakaily, Xena

    2014-08-01

    Reconstructing defects of the oral mucosa or skin of the lower one-third of the face can be accomplished by a variety of techniques. This article presents two versions of the platysma myocutaneous flap, which is a reliable, axial pattern, pedicled flap capable of providing excellent one-stage reconstruction of such defects. As discussed herein, the superiorly based and posteriorly based versions of the flap have wide application in the oral and facial region. Also provided is a review of other uses of this flap in head and neck surgery. PMID:24958382

  13. 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...... 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...

  14. 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.

  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

    predictive control was tested successfully on this demonstrator turbine. An average flapwise blade root load reduction of 14% was achieved during a 38 minute test, and a reduction of 20% of the amplitude of the 1P loads was measured. A system identification test was also performed, and an identified linear...... 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...... and the measurements in terms of flapwise blade root moment spectral densities, in spite of significant differences between the identified linear model and the model predictive control design model....

  16. Effects of primary rotor parameters on flapping dynamics

    Science.gov (United States)

    Chen, R. T. N.

    1980-01-01

    The effects of flapping dynamics of four main rotor design features that influence the agility, stability, and operational safety of helicopters are studied. The parameters include flapping hinge offset, flapping hinge restraint, pitch-flap coupling, and blade lock number. First, the flapping equations of motion are derived that explicitly contain the design parameters. The dynamic equations are then developed for the tip-path plane, and the influence of individual and combined variations in the design parameters determined. The steady state flapping response is examined with respect to control input and aircraft angular rate which leads to a feedforward control law for control decoupling through cross feed, and a feedback control law to decouple the steady state flapping response. The condition for achieving perfect decoupling of the flapping response due to aircraft pitch and roll rates without using feedback control is also found for the hover case. It is indicated that the frequency of the regressing flapping mode of the rotor system can become low enough to require consideration in the assessment of handling characteristics.

  17. Cervicofacial flap revisited

    Directory of Open Access Journals (Sweden)

    Dhananjay V. Nakade

    2016-11-01

    Conclusions: Cervicofacial flap is simple, easy to operate, consume less operating time as compared to microvascular flap. It is less complicated and especially useful in diabetic, hypertensives and old debilitated patients with high risk of anaesthesia. [Int J Res Med Sci 2016; 4(11.000: 4669-4674

  18. Application of output feedback sliding mode control to active flutter suppression of two-dimensional airfoil

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The effectiveness of the sliding mode control(SMC) method for active flutter suppression(AFS) and the issues concerning control system discretization and control input constraints were studied using a typical two-dimensional airfoil.The airfoil has a trailing-edge flap for flutter control.The aeroelastic system involves a two-degrees-of-freedom motion(pitch and plunge),and the equations were constructed by utilizing quasi-steady aerodynamic forces.The control system,designed by the output feedback SMC method,was incorporated to suppress the pitch-plunge flutter.Meanwhile,the system discretization and the flap deflection constraints were implemented.Then,a classical Runge-Kutta(RK) algorithm was utilized for numerical calculations.The results indicated that the close-loop system with the SMC system could be stable at a speed above the flutter boundary.However,when the flap deflection limits are reached,the close-loop system with the simple discretized control system loses control.Furthermore,control compensation developed by theoretical analysis was proposed to make the system stable again.The parameter perturbations and the time delay effects were also discussed in this paper.

  19. Pedicled perforator flaps

    DEFF Research Database (Denmark)

    Demirtas, Yener; Ozturk, Nuray; Kelahmetoglu, Osman;

    2009-01-01

    Described in this study is a surgical concept that supports the "consider and use a pedicled perforator flap whenever possible and indicated" approach to reconstruct a particular skin defect. The operation is entirely free-style; the only principle is to obtain a pedicled perforator flap to recon......Described in this study is a surgical concept that supports the "consider and use a pedicled perforator flap whenever possible and indicated" approach to reconstruct a particular skin defect. The operation is entirely free-style; the only principle is to obtain a pedicled perforator flap...... more practical and creative to use a free-style manner during pedicled perforator flap surgery, instead of being obliged to predefined templates for this type of procedure....

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

    CERN Document Server

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

    2014-01-01

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

  1. Leaf spring flapping hinge for wind turbines with device for control of blade angle. Blattfeder-Schlaggelenk fuer Windturbinen mit Vorrichtung zur Blattwinkelsteuerung

    Energy Technology Data Exchange (ETDEWEB)

    Gasch, R.; Person, M.

    1985-05-30

    The device described combines the properties of a flapping hinge, a link for adjusting the blade angle and an elastic return spring. According to the invention, these properties are achieved by two links fixing the axis of flapping and, by winding up the leaf spring, producing adjustment of the blade angle.

  2. Design of a high-lift experiment in water including active flow control

    Science.gov (United States)

    Beutel, T.; Sattler, S.; El Sayed, Y.; Schwerter, M.; Zander, M.; Büttgenbach, S.; Leester-Schädel, M.; Radespiel, R.; Sinapius, M.; Wierach, P.

    2014-07-01

    This paper describes the structural design of an active flow-control experiment. The aim of the experiment is to investigate the increase in efficiency of an internally blown Coanda flap using unsteady blowing. The system uses tailor-made microelectromechanical (MEMS) pressure sensors to determine the state of the oncoming flow and an actuated lip to regulate the mass flow and velocity of a stream near a wall over the internally blown flap. Sensors and actuators are integrated into a highly loaded system that is extremely compact. The sensors are connected to a bus system that feeds the data into a real-time control system. The piezoelectric actuators using the d 33 effect at a comparable low voltage of 120 V are integrated into a lip that controls the blowout slot height. The system is designed for closed-loop control that efficiently avoids flow separation on the Coanda flap. The setup is designed for water-tunnel experiments in order to reduce the free-stream velocity and the system’s control frequency by a factor of 10 compared with that in air. This paper outlines the function and verification of the system’s main components and their development.

  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

    2016-01-01

    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. PMID:27659066

  4. Flapping of Insectile Wings

    Science.gov (United States)

    Huang, Yangyang; Kanso, Eva

    2015-11-01

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

  5. The effect of large aspect ratio wing yaw on active separation control

    Science.gov (United States)

    Tewes, Philipp; Taubert, Lutz; Wygnanski, Israel

    2014-11-01

    The applicability of the boundary layer independence principle to turbulent boundary layers developing on infinitely yawed wings, suggested that active separation control might be carried out differently to the two presumably independent developing boundary layers. At low incidence or flap deflection the control of the spanwise component of the flow is effective provided the aggregate number of actuators is small. In this case the actuator jets provide jet-curtains that virtually eliminate the spanwise flow component of the flow in their vicinity. At higher incidence or flap deflection, the focus of the active separation control has to shift to the chordwise component that has to overcome a high adverse pressure gradient. The idea was proven experimentally on a flapped wing based on a NACA 0012 airfoil that could be swept back and forward while being suspended from a ceiling of a wind tunnel connected to a six-component balance. The experiments were carried out at Reynolds numbers varying between 300,000 and 500,000. The project was supported in part by a grant from AFOSR.

  6. Perforator Flaps for Perineal Reconstructions

    OpenAIRE

    Niranjan, Niri S.

    2006-01-01

    Whenever there is soft tissue loss from the perineum there are many options for reconstruction. These include allowing the wound to heal by secondary intention and the use of local random or axial pattern flaps, regional flaps, or free flaps. The axial skin flap can be defined as a flap based on known constant vessels of the subcutaneous tissue and its vena comitantes. The perforator flap on the other hand is a randomly selected perforator consisting of an artery with vena comitantes, which p...

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

    Science.gov (United States)

    Stowers, Amanda K; Lentink, David

    2015-04-01

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

  8. Coronally positioned flap with or without acellular dermal matrix graft in the treatment of class II gingival recession defects: A randomized controlled clinical study

    Directory of Open Access Journals (Sweden)

    Sunitha Jagannathachary

    2010-01-01

    Full Text Available The aim of the randomized controlled single blind study is to evaluate the treatment of Miller′s class II gingival recessions by coronally positioned flap (CPF with or without acellular dermal matrix allograft (ADMA. Ten patients with 20 sites with maxillary bilateral Miller′s class II facial recession defects were selected randomly into two groups of test (ADMA+CPF and control (CPF alone group with each group having 10 recession defects to be treated. The clinical parameters included plaque index (PI, gingival index (GI, probing pocket depth (PPD, clinical attachment level (CAL, recession height (RH, recession width (RW, height of the keratinized tissue (HKT, and thickness of the keratinized tissue (TKT. These measurements were recorded at baseline and after 6 months post-surgery. Statistical analysis was made by the paired "t" test for intragroup and intergroup comparison was done by the unpaired "t" test. The percentage of root coverage for both the experimental and control groups were 82.2% and 50%, respectively. The changes from baseline to 6 months were significant in both the groups for PD, CAL, and RH; however, for parameters such as RW, HKT, and TKT significance was seen only in the experimental group. On comparison between two groups, only TKT showed statistically significance. It can be concluded that the amount of root coverage obtained with ADMA + CPF was superior compared to CPF alone.

  9. Quadrilobed superior gluteal artery perforator flap for sacrococcygeal defects

    Institute of Scientific and Technical Information of China (English)

    HAI Heng-lin; SHEN Chuan-an; CHAI Jia-ke; LI Hua-tao; YU Yong-ming; LI Da-wei

    2013-01-01

    Background Perforator flaps are used extensively in repairing soft tissue defects.Superior gluteal artery perforatorflaps are used for repairing sacral defects,but the tension required for direct closure of the donor area after harvesting ofrelatively large flaps carries a risk of postoperative dehiscence.This research was to investigate a modified superiorgluteal artery perforator flap for repairing sacrococcygeal soft tissue defects.Methods From June 2003 to April 2010,we used our newly designed superior gluteal artery perforator flap for repair of sacrococcygeal soft tissue defects in 10 patients (study group).The wound and donor areas were measured,and the flaps were designed accordingly.Wound healing was assessed over a follow-up period of 6-38 months.From January 1998 to February 2003,twelve patients with sacrococcygeal pressure sores were treated with traditional methods,VY advancement flaps or oblong flaps,as control group.Results After debridement,the soft tissue defects ranged from 12 cm × 10 cm to 26 cm × 22 cm (mean 16.3 cm x 13.5cm).Four patients were treated using right-sided flaps ranging from 15 cm × 11 cm to 25 cm × 20 cm (mean 18.2 cm × 14cm).Four patients were treated using left-sided flaps,and two were treated using both right-and left-sided flaps.Suction drains were removed on postoperative Days 3-21 (mean 5.9) and sutures were removed on postoperative Days 12-14.Each flap included 1-2 perforators for each of the donor and recipient sites.Donor sites were closed directly.All flaps survived.In eight patients,the wounds healed after single-stage surgery.After further debridement,the wounds of the remaining two patients were considered healed on postoperative Days 26 and 33,respectively.The rate of first intention in the study group (80%,8/10) significantly increased than that of control group ((25%,3/12),X2=4.583,P=-0.032).Follow-up examinations found that the flaps had a soft texture without ulceration.In the two patients without

  10. Blowing Flap Experiment: PIV Measurements

    Science.gov (United States)

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

    2004-01-01

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

  11. Efficiency in Controlling Activities

    OpenAIRE

    Van Nguyen, Tuyen

    2015-01-01

    Controlling is essential for financial success of corporations. An efficient controlling system should be implemented in order to manage financial performance from income, expense to profitability. The purpose of the thesis is to provide insight knowledge towards corporate accounting management as well as to propose potential improvement for the existing controlling system of the case company, which is Bosch Rexroth Japan. The theoretical framework creates the knowledge foundation for re...

  12. The Evolution of Perforator Flaps

    OpenAIRE

    Khan, Farah N.; Spiegel, Aldona J.

    2006-01-01

    Perforator flaps have recently become ubiquitous in the field of plastic surgery. To understand and appreciate their unique nature, it is necessary to compare and contrast them with the development of other types of flaps. A complete yet abridged version of the history of flap surgery is presented in this article. Beginning with Sushruta's Indian cheek flap method for nasal reconstruction, a trip through time and space is taken to highlight the milestones leading to the evolution of the perfo...

  13. The Versatile Modiolus Perforator Flap

    DEFF Research Database (Denmark)

    Gunnarsson, Gudjon Leifur; Thomsen, Jorn Bo

    2016-01-01

    BACKGROUND: Perforator flaps are well established, and their usefulness as freestyle island flaps is recognized. The whereabouts of vascular perforators and classification of perforator flaps in the face are a debated subject, despite several anatomical studies showing similar consistency. In our...

  14. 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....... With the DEAP based high power actuator, it is expected to make a reliable and light solution with superior controllability. The current DEAP technology requires high DC voltage in the range of kV to fully utilize the DEAP material as an actuator. In this paper we propose a flyback converter topology to obtain...

  15. Pectoralis myocutaneous flap for salvage of necrotic wounds

    Energy Technology Data Exchange (ETDEWEB)

    Price, J.C.; Davis, R.K.; Koltai, P.J.

    1985-02-01

    The authors have utilized six pectoralis major myocutaneous flaps in attempts to salvage extensive necrotic wounds of the pharynx and neck. The flap was employed in the following situations: massive necrosis of the entire neck skin with both carotid artery systems exposed, radiation necrosis of the neck skin with exposure of carotid artery, dehiscence of gastric pull-up from pharynx with resultant carotid exposure, failed trapezius flap in a radionecrotic oral cavity, and two cases of pharyngocutaneous fistula with extensive soft tissue necrosis. These flaps achieved healing in all cases. One death occurred 3 weeks following complete cutaneous healing secondary to a ruptured carotid pseudoaneurysm. One flap underwent total skin loss but the entirety of the muscle survived and the fistula was successfully closed with the back of the muscle being subsequently skin grafted. One case of dehiscence of the flap from oral mucosa resulted in a minor exposure of mandible with limited osteoradionecrosis controlled by topical means. This flap has performed extremely well in these precarious and difficult situations that previously may not have been salvageable. It has also been effective in abbreviating the required hospitalization and wound care. The authors conclude that the pectoralis myocutaneous flap should be the primary choice for the management of extensive postsurgical wound necrosis.

  16. Pectoralis myocutaneous flap for salvage of necrotic wounds

    International Nuclear Information System (INIS)

    The authors have utilized six pectoralis major myocutaneous flaps in attempts to salvage extensive necrotic wounds of the pharynx and neck. The flap was employed in the following situations: massive necrosis of the entire neck skin with both carotid artery systems exposed, radiation necrosis of the neck skin with exposure of carotid artery, dehiscence of gastric pull-up from pharynx with resultant carotid exposure, failed trapezius flap in a radionecrotic oral cavity, and two cases of pharyngocutaneous fistula with extensive soft tissue necrosis. These flaps achieved healing in all cases. One death occurred 3 weeks following complete cutaneous healing secondary to a ruptured carotid pseudoaneurysm. One flap underwent total skin loss but the entirety of the muscle survived and the fistula was successfully closed with the back of the muscle being subsequently skin grafted. One case of dehiscence of the flap from oral mucosa resulted in a minor exposure of mandible with limited osteoradionecrosis controlled by topical means. This flap has performed extremely well in these precarious and difficult situations that previously may not have been salvageable. It has also been effective in abbreviating the required hospitalization and wound care. The authors conclude that the pectoralis myocutaneous flap should be the primary choice for the management of extensive postsurgical wound necrosis

  17. Spectral analysis of blood perfusion in the free latissimus dorsi myocutaneous flap and in normal skin

    International Nuclear Information System (INIS)

    To find the properties in the oscillatory components of the cutaneous blood flow on the successful free flap, a wavelet transform was applied to the laser Doppler flowmetry (LDF) signals which were measured simultaneously on the surfaces of the free latissimus dorsi myocutaneous flap and on the adjacent intact skin of the healthy limb, of 18 patients. The frequency interval from 0.0095 to 1.6 Hz was examined and was divided into five subintervals (I: 0.0095-0.021 Hz; II: 0.021-0.052 Hz; III: 0.052-0.145 Hz; IV: 0.145-0.6 Hz and V: 0.6-1.6 Hz) corresponding to endothelial metabolic, neurogenic, myogenic, respiratory and cardiac origins. The average amplitude and total power in the frequency range 0.0095-1.6 Hz as well as within subintervals I, II, IV and V were significantly lower for signals measured on the free flap than those obtained in the healthy limb. However in interval III, they were significantly higher. The normalized spectral amplitude and power in the free flap were significantly lower in only two intervals, I and II, yet in interval III they were significantly higher; no statistical significance was observed in intervals IV and V. The distinctive finding made in this study, aside from the decrease of endothelial metabolic processes and sympathetic control, was the significant increase of myogenic activity in the free flap. It is hoped that this work will contribute towards knowledge on blood circulation in free flaps and make the monitoring by LDF more reliable

  18. 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.

  19. 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...

  20. Development of Variable Camber Continuous Trailing Edge Flap System

    Science.gov (United States)

    Urnes, Jim, Sr.; Nguyen, Nhan T.; Dykman, John

    2012-01-01

    This presentation describes the current status of the joint NASA/Boeing collaboration on the development of a variable camber continuous trailing edge flap system for use in wing shaping control for cruise drag reduction.

  1. Effect of intraoperative platelet-rich plasma and fibrin glue application on skin flap survival.

    Science.gov (United States)

    Findikcioglu, Fulya; Findikcioglu, Kemal; Yavuzer, Reha; Lortlar, Nese; Atabay, Kenan

    2012-09-01

    The experiment was designed to compare the effect of intraoperative platelet-rich plasma (PRP) and fibrin glue application on skin flap survival. In this study, bilateral epigastric flaps were elevated in 24 rats. The right-side flaps were used as the control of the left-side flaps. Platelet-rich plasma, fibrin glue, and thrombin had been applied under the flap sites in groups 1, 2, and 3, respectively. Five days later, all flap pedicles were ligated. Necrotic area measurements, microangiography, and histologic and immunohistochemical evaluations were performed to compare the groups. Platelet-rich plasma reduced necrotic area percentages as compared with other groups. Histologically and microangiographically increased number of arterioles were observed in PRP groups. Thrombin when used alone increased flap necrosis. Vascular endothelial growth factor, platelet-derived growth factor, and transforming growth factor β3 primary antibody staining showed increased neovascularization and reepithelialization in all PRP-applied flaps. This study demonstrated that PRP, when applied intraoperatively under the skin flap, may enhance flap survival. Thrombin used alone was found to be unsuitable in flap surgery.

  2. Surgical procedure of Free Flap. Main nursing care

    Directory of Open Access Journals (Sweden)

    Manuel Molina López

    2010-05-01

    Full Text Available The free flap surgical technique is used to cover extensive skin loss areas and situations where no flap is available, or in axial zones. The great breackthrough in the field of reconstructive surgical techniques and the creation of new units where these complex techniques are used, means that the nursing staff who work in these hospital units are adquiring greater protagonism in caring for, and the subsequent success of this type of surgery in which the problems of collaboration in all the perioperative phases depend entirely on the nursing team.The collaborative nursing problems could be defined as real or potential health problems, where users need nursing staff to follow the treatment and control procedures prescribed by other professional, generally doctors, who control and are responsible for the final outcome.While planning collaborative objectives and activities it should be taken into account that the function of the nursing staff is twofold: on the one hand, the patient must be taken care of as prescribed by other professionals and, on the other hand, it should bring into play cognitive elements (knowledge and know-how and clinical judgment when executing these in controlling the patients evolution.In this article our intention is to give an interesting and comprehensive description of the free flap surgical technique, its pros and cons, and identify the principal collaborative problems which nursing will have to deal with in each one of the perioperative phases, the number and specific nature of such oblige nursing on many occasions, to update and/or acquire new skills.

  3. Active control of free flight manoeuvres in a hawkmoth, Agrius convolvuli.

    Science.gov (United States)

    Wang, Hao; Ando, Noriyasu; Kanzaki, Ryohei

    2008-02-01

    By combining optical triangulation with the comb-fringe technique and dual-channel telemetry, wing kinematics and body attitudes accompanying muscle activities of free-flying male hawkmoths were recorded synchronously when they performed flight manoeuvres elicited by a female sex pheromone. The results indicate that the wing leading edge angular position at the ventral stroke reversal, which can be decomposed by two orthogonal angular parameters (a flapping angle and a deviation angle), is well controllable. Two specific flight muscles, the dorsal-ventral muscle (DVM, indirect muscle, a wing elevator) and the third axillary muscle (3AXM, direct muscle, a wing retractor), can modulate the flapping angle and the deviation angle, respectively, by means of regulating the firing timing of muscle activities. The firing timing can be expressed by the firing latency absolutely, which is just before the timing of ventral stroke reversal. The results illustrate that lengthening the firing latency of the DVM and of the 3AXM can increase the flapping angle and the deviation angle, respectively, which both strengthen the downstroke at the ventral stroke reversal. The relationship of bilateral asymmetry shows that the bilateral differences in the firing latency of the DVM and of the 3AXM will cause bilateral differences in the wing position, which accompany the variations of yaw and roll angles in time course. This implies the contribution of the two muscles to active steering controls during turning or banking, though the DVM being an indirect muscle was generally treated as a power generator. Finally, the relationship between the pitch angle and the 3AXM latency, deduced from the relationships between the pitch angle and the deviation angle and between the deviation angle and the 3AXM latency, shows that lengthening the 3AXM latency can increase the pitch angle at the ventral stroke reversal by moving the wing tip far away from the centre of gravity of the body, which

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

    OpenAIRE

    Sandra Olivia; Natalina Natalina; Felix Hartono

    2013-01-01

    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 rad...

  5. Experimental investigation on plain flap control characteristics in slipstream of small scale propeller%微小型螺旋桨滑流内舵面操纵特性实验研究

    Institute of Scientific and Technical Information of China (English)

    吴大卫; 王亮; 李寒冰; 李书

    2011-01-01

    Mini vertical takeoff and landing ( VTOL) aircraft popularly control their attitudes by deflecting the control surface in propeller slipstream when hovering, but usually lack of enough control moment. This paper shows the systematic experiments about the assembly of static propellers with small scale and wing with plain flap. According to analyzing the data, this paper indicates that plain flap control characteristics can be modified by selecting optimal propeller geometric parameters and gives a series of conclusions about the configuration influence of wing with plain flap on control characteristics. The results can be referenced in designing phase for increasing the control power of these aircrafts.%微小型垂直起降飞行器悬停时往往采用螺旋桨滑流内舵面偏转进行姿态控制,但容易出现操纵力矩不足的问题.本文针对这一问题对微小型静推力状态螺旋桨与带舵面机翼的组合体进行了系统性的实验.通过对实验数据分析,本文指出通过优选螺旋桨几何参数可以改善操纵特性,并得出带舵面机翼不同构型对操纵特性影响的一系列结论,为如何改善此类飞行器悬停时的操纵特性提供了设计参考.

  6. Flag flapping in a channel

    Science.gov (United States)

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

    2015-11-01

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

  7. 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.

  8. 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...... theory. The investigation then focuses on operation in non-uniform wind _eld conditions. Firstly, the deterministic uctuation in local tip speed ratio due to wind shear was evaluated. The second e_ect is associated with delays in adapting the rotor speed to time varying inow. The increase of power...

  9. 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...... generation has been using blade element momentum theory. As a first step, the operation in non-uniform wind field conditions was analysed. Firstly, the deterministic fluctuation in local tip speed ratio due to wind shear was evaluated. The second effect is associated with time delays in adapting the rotor...

  10. 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.

  11. 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

  12. Active Flow Control Using Sweeping Jet Actuators on a Semi-Span Wing Model

    Science.gov (United States)

    Melton, LaTunia Pack; Koklu, Mehti

    2016-01-01

    Wind tunnel experiments were performed using active flow control on an unswept semispan wing model with a 30% chord trailing edge flap to aid in the selection of actuators for a planned high Reynolds number experiment. Two sweeping jet actuator sizes were investigated to determine the influence of actuator size on the active flow control system efficiency. Sweeping jet actuators with orifice sizes of 1 mm x 2 mm and 2 mm x 4 mm were selected because of the differences in actuator jet sweep angle. The parameters that were varied include actuator momentum, freestream velocity, and trailing edge flap deflection angle. Steady and unsteady pressure data, Particle Image Velocimetry data, and force and moment data were acquired to assess the performance of the two actuators. In addition to the wind tunnel experiments, benchtop studies of the actuators were performed to characterize the jets produced by each actuator. Benchtop investigations of the smaller actuator reveal that the jet exiting the actuator has a reduced sweep angle compared to published data for larger versions of this type of actuator. The larger actuator produces an oscillating jet that attaches to the external di?user walls at low supply pressures and produces the expected sweep angles. The AFC results using the smaller actuators show that while the actuators can control flow separation, the selected spacing of 3.3 cm may be too large due to the reduced sweep angle. In comparison, the spacing for the larger actuators, 6.6 cm, appears to be optimal for the Mach numbers investigated. Particle Image Velocimetry results are presented and show how the wall jets produced by the actuators cause the flow to attach to the flap surface.

  13. ABOUT CONTROLLING OF SCIENTIFIC ACTIVITY

    Directory of Open Access Journals (Sweden)

    Mukhin V. V.

    2014-06-01

    Full Text Available We have selected the new area of controlling - scientific activity controlling. We consider some problems of development in this field, primarily the problem of selection of key performance indicators. It’s been founded that administrative measures stimulated the pursuit of a number of articles published in scientific journals hinders the development of science. Methodological errors - emphasis on citation indexes, impact factors, etc. - lead to wrong management decisions. As the experience of the UK, an expertise should be applied in the management of science. The article briefly discusses some of the drawbacks of the system of scientific specialties. It is proposed to expand research on the science of science and scientific activity controlling. We have also discussed the problems of controlling in applied research organizations

  14. Development of radiation injury model in musculocutaneous flaps used for breast reconstruction

    International Nuclear Information System (INIS)

    Purpose/Objective: Occasionally it becomes necessary to treat women who have undergone a mastectomy and immediate musculocutaneous flap breast reconstruction with radiation therapy for microscopically positive margins. Radiation therapy is known to have a wide range of deleterious effects on living tissue and, specifically composite flaps. Small vessel thrombosis, necrosis, lymphedema, fibroblast dysfunction, and severe contracture are just a few of these effects that may lead to flap compromise. An animal model of the TRAM flap has been described: however, a thorough review of the literature finds a few experimental studies on the effects of radiation on musculocutaneous flaps. This study is designed to produce a reproducible and quantitative model of radiation injury that can service as a basis for further investigation. Materials and Methods: Eleven adult male Sprague-Dawley rats underwent a standardized rectus abdominis musculocutaneous flap based on the superior epigastric artery. Two control rats had flaps raised but did not receive radiation. The flaps were allowed to heal six weeks and the remaining rats were randomized to three groups of three rats each. The first group received 2000 rads in five fractions, the second 3000 rads in ten fractions, and the third 3000 rads in 15 fractions. Radiation was delivered via a dual energy clinical linear accelerator centered over the flap. The rats were sacrificed at eight weeks from the last dose of radiation. The flaps were subjected to elasticity measuring by standard Instron tensiometer, total surface area measurements and standard histology stains, as well as elastin stains and Masson Trichrome stains. Results: The total area of the flap measured by Mocha analysis decreased in all rats from the initial 30 cm2. However, the decrease in irradiated flaps was greater when compared to non-irradiated controls and the degree of contracture increased as the amount of radiation increased. Control flaps averaged 16.27 cm2

  15. Dynamics of a pneumatic artificial muscle actuation system driving a trailing edge flap

    Science.gov (United States)

    Woods, Benjamin K. S.; Kothera, Curt S.; Wang, Gang; Wereley, Norman M.

    2014-09-01

    This study presents a time domain dynamic model of an antagonistic pneumatic artificial muscle (PAM) driven trailing edge flap (TEF) system for next generation active helicopter rotors. Active rotor concepts are currently being widely researched in the rotorcraft community as a means to provide a significant leap forward in performance through primary aircraft control, vibration mitigation and noise reduction. Recent work has shown PAMs to be a promising candidate for active rotor actuation due to their combination of high force, large stroke, light weight, and suitable bandwidth. When arranged into biologically inspired agonist/antagonist muscle pairs they can produce bidirectional torques for effectively driving a TEF. However, there are no analytical dynamic models in the literature that can accurately capture the behavior of such systems across the broad range of frequencies required for this demanding application. This work combines mechanical, pneumatic, and aerodynamic component models into a global flap system model developed for the Bell 407 rotor system. This model can accurately predict pressure, force, and flap angle response to pneumatic control valve inputs over a range of operating frequencies from 7 to 35 Hz (1/rev to 5/rev for the Bell 407) and operating pressures from 30 to 90 psi.

  16. Dynamics of a pneumatic artificial muscle actuation system driving a trailing edge flap

    International Nuclear Information System (INIS)

    This study presents a time domain dynamic model of an antagonistic pneumatic artificial muscle (PAM) driven trailing edge flap (TEF) system for next generation active helicopter rotors. Active rotor concepts are currently being widely researched in the rotorcraft community as a means to provide a significant leap forward in performance through primary aircraft control, vibration mitigation and noise reduction. Recent work has shown PAMs to be a promising candidate for active rotor actuation due to their combination of high force, large stroke, light weight, and suitable bandwidth. When arranged into biologically inspired agonist/antagonist muscle pairs they can produce bidirectional torques for effectively driving a TEF. However, there are no analytical dynamic models in the literature that can accurately capture the behavior of such systems across the broad range of frequencies required for this demanding application. This work combines mechanical, pneumatic, and aerodynamic component models into a global flap system model developed for the Bell 407 rotor system. This model can accurately predict pressure, force, and flap angle response to pneumatic control valve inputs over a range of operating frequencies from 7 to 35 Hz (1/rev to 5/rev for the Bell 407) and operating pressures from 30 to 90 psi. (paper)

  17. Flap-Edge Blowing Experiments

    Science.gov (United States)

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

    2003-01-01

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

  18. A standardized model for predicting flap failure using indocyanine green dye

    Science.gov (United States)

    Zimmermann, Terence M.; Moore, Lindsay S.; Warram, Jason M.; Greene, Benjamin J.; Nakhmani, Arie; Korb, Melissa L.; Rosenthal, Eben L.

    2016-03-01

    Techniques that provide a non-invasive method for evaluation of intraoperative skin flap perfusion are currently available but underutilized. We hypothesize that intraoperative vascular imaging can be used to reliably assess skin flap perfusion and elucidate areas of future necrosis by means of a standardized critical perfusion threshold. Five animal groups (negative controls, n=4; positive controls, n=5; chemotherapy group, n=5; radiation group, n=5; chemoradiation group, n=5) underwent pre-flap treatments two weeks prior to undergoing random pattern dorsal fasciocutaneous flaps with a length to width ratio of 2:1 (3 x 1.5 cm). Flap perfusion was assessed via laser-assisted indocyanine green dye angiography and compared to standard clinical assessment for predictive accuracy of flap necrosis. For estimating flap-failure, clinical prediction achieved a sensitivity of 79.3% and a specificity of 90.5%. When average flap perfusion was more than three standard deviations below the average flap perfusion for the negative control group at the time of the flap procedure (144.3+/-17.05 absolute perfusion units), laser-assisted indocyanine green dye angiography achieved a sensitivity of 81.1% and a specificity of 97.3%. When absolute perfusion units were seven standard deviations below the average flap perfusion for the negative control group, specificity of necrosis prediction was 100%. Quantitative absolute perfusion units can improve specificity for intraoperative prediction of viable tissue. Using this strategy, a positive predictive threshold of flap failure can be standardized for clinical use.

  19. Active control: Wind turbine model

    DEFF Research Database (Denmark)

    Bindner, H.

    1999-01-01

    validation as well as parameter estimation. The model includes a simple model of the structure of the turbine including tower and flapwise blade bending,a detailed model of the gear box and induction generator, a linearized aerodynamic model including modelling of induction lag and actuator and sensor models......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...

  20. Handling Qualities Results of an Initial Geared Flap Tilt Wing Piloted Simulation

    Science.gov (United States)

    Guerrero, Lourdes M.; Corliss, Lloyd D.

    1991-01-01

    An exploratory simulation study of a novel approach to pitch control for a tilt wing aircraft was conducted in 1990 on the NASA-Ames Vertical Motion Simulator. The purpose of the study was to evaluate and compare the handling qualities of both a conventional and a geared flap tilt wing control configuration. The geared flap is an innovative control concept which has the potential for reducing or eliminating the horizontal pitch control tail rotor or reaction jets required by prior tilt wing designs. The handling qualities results of the geared flap control configuration are presented in this paper and compared to the conventional (programmed flap) tilt wing control configuration. This paper also describes the geared flap concept, the tilt wing aircraft, the simulation model, the simulation facility and experiment setup, and the pilot evaluation tasks and procedures.

  1. Small scale wind tunnel model investigation of hybrid high lift systems combining upper surface blowing with the internally blown flap

    Science.gov (United States)

    Waites, W. L.; Chin, Y. T.

    1974-01-01

    A small-scale wind tunnel test of a two engine hybrid model with upper surface blowing on a simulated expandable duct internally blown flap was accomplished in a two phase program. The low wing Phase I model utilized 0.126c radius Jacobs/Hurkamp flaps and 0.337c radius Coanda flaps. The high wing Phase II model was utilized for continued studies on the Jacobs/Hurkamp flap. Principal study areas included: basic data both engines operative and with an engine out, control flap utilization, horizontal tail effectiveness, spoiler effectiveness, USB nacelle deflector study and USB/IBF pressure ratio effects.

  2. 14 CFR 23.701 - Flap interconnection.

    Science.gov (United States)

    2010-01-01

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

  3. Wind-tunnel investigation of a Fowler flap and spoiler for an advanced general aviation wing

    Science.gov (United States)

    Paulson, J. W., Jr.

    1976-01-01

    The wing was tested without fuselage or empennage and was fitted with approximately three-quarter span Fowler flaps and half span spoilers. The spoilers were hinged at the 70 percent chord point and vented when the flaps were deflected. Static longitudinal and lateral aerodynamic data were obtained over an angle of attack range of -8 deg to 22 deg for various flap deflections and positions, spoiler geometries, and vent lip geometries. Lateral characteristics indicate that the spoilers are generally adequate for lateral control. In general, the spoiler effectiveness increases with increasing angle of attack, increases with increasing flap deflections, and is influenced by vent lip geometry. In addition, the data show that some two-dimensional effects on spoiler effectiveness are reduced in the three-dimensional case. Results also indicate significant increase in lift coefficient as the Fowler flaps are deflected; when the flap was fully deflected, the maximum wing lift coefficient was increased about 96 percent.

  4. A morphing trailing edge flap system for wind turbine blades

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Barlas, Athanasios; Løgstrup Andersen, Tom

    2015-01-01

    The development of a morphing trailing edge system for wind turbines, also called a flap system, is presented. The functionality is simple as the flap deflection is controlled by pressurized air or a fluid in a number of voids in the flap made of an elastic material. It is thus a robust system...... as no mechanical or metal parts are used. The prototypes tested in the laboratory and on a blade section in a wind tunnel in the period from 2007-2010 demonstrated the functionality and the aerodynamic performance of the flap concept. In a recent research and development project INDUFLAP from 2011-2014 the flap...... and glued together with a load carrying part with a connector part that allows an easy attachment on the blade section. After tests in the laboratory the flap was mounted on a 2m long blade section mounted on a newly developed test rig. A 10m long boom with the blade section was installed on a 100kW turbine...

  5. 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

    tunnel experiment in 2009 with promising results. This led in 2011 to initiation of a new research project INDUFLAP with the main aim to transfer the flap technology to industry as concerns manufacturing and testing. Three industrial partners are participating in the project. Rehau (DE) and Dansk Gummi...... 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...

  6. 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.

  7. Acetylcysteine in random skin flap in rats

    Directory of Open Access Journals (Sweden)

    Abla Luiz Eduardo Felipe

    2005-01-01

    Full Text Available PURPOSE: Analyze the ability of Acetylcysteine to reduce distal necrosis in a random skin flap, in the rat. METHODS: The present study utilized 28 adult male Wistar-EPM rats distributed, at random, in two groups of 14 animals. Control group rats (CG received distilled water and Acetylcysteine group animals (NACG received NAC (300 mg/kg by oral infusion, 15 minutes before flap elevation. On the seventh postoperative day, percentage of distal necrosis was determined and skin samples collected in order to allow determination of MDA levels. RESULTS: The mean necrotic area in CG group (control was 66 % and in NACG group (Acetylcysteine 52 %, a statistically significant difference according to the Mann-Whitney test (U calc = 25; U crit = 45. MDA levels were lower in the CG flap skin samples than in the NACG samples (U calc = 24; U crit = 45, the oposite being true in the normal skin samples (U calc = 10; U crit = 45. CONCLUSION: Acetylcysteine was effective, according to the model used, reducing the percentage of distal necrosis in NACG rats.

  8. Radiated noise from an externally blown flap

    Science.gov (United States)

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

    1975-01-01

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

  9. 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.

  10. 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...

  11. A Digital Controller for Active Aeroelastic Controls

    OpenAIRE

    Ueda, Tetsuhiko; MUROTA, Katsuichi; 上田, 哲彦; 室田, 勝一

    1989-01-01

    A high-speed digital controller for aeroelastic controls was designed and made. The purpose was to minimize adverse phase lag which is inevitably produced by the CPU time of digital processing. The delay deteriorates control performances on rather rapid phenomena like aircraft flutter. With fix-point operation the controller realized 417 microseconds of throughput time including the A/D and D/A conversion. This corresponds to a high sampling rate of 2.4kHz. The controller furnishes two channe...

  12. 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.

  13. 2D numerical comparison of trailing edge flaps - UpWind WP1B3

    DEFF Research Database (Denmark)

    Buhl, Thomas; Andersen, Peter Bjørn; Barlas, T.K.

    This report covers the investigations and comparisons of trailing edge flaps carried out by Delft and Risø. The work is a part of the W1B3 work package of the UpWind EU-project. This report covers only 2D test cases with simple control of the trailing edge flap with the objective of keeping CL co...

  14. 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

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

    DEFF Research Database (Denmark)

    Bergami, Leonardo; Hansen, Morten Hartvig

    2016-01-01

    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......A high-fidelity linear time-invariant model of the aero-servo-elastic response of a wind turbine with trailing-edge flaps is presented and used for systematic tuning of an individual flap controller. The model includes the quasi-steady aerodynamic effects of trailing-edge flaps on wind turbine...... blades and is integrated in the linear aeroelastic code HAWCStab2. The dynamic response predicted by the linear model is validated against non-linear simulations, and the quasi-steady assumption does not cause any significant response bias for flap deflection with frequencies up to 2-3 Hz. The linear...

  16. Effects of hyperbaric oxygen preconditioning on ischemia-reperfusion inflammation and skin flap survival

    Institute of Scientific and Technical Information of China (English)

    QI Zheng; GAO Chun-jin; WANG You-bin; MA Xue-mei; ZHAO Ling; LIU Fu-jia; LIU Xue-hua

    2013-01-01

    Background Hyperbaric oxygen preconditioning (HBO) is a new method of ischemia preconditioning.In this study,we examined its effects on skin flap survival and the mechanisms involved.Methods Thirty-six rats were divided into three groups:HBO preconditioning,control,and sham groups.An extended epigastric adipocutaneous flap based on the right superficial epigastric artery and vein was raised.A 3-hour period of flap ischemia was induced by clamping the pedicle vessels with a microvascular clamp.At the end of ischemia induction,the clamp was removed and the flap was resutured.Rats in the HBO preconditioning group were treated with HBO four times before surgery.Microcirculation in the skin flap was measured on postoperative days 1,3 and 5.The size of the flap was measured on postoperative day 5,before the animals were sacrificed.Samples of the skin flap were prepared and stained with hematoxylin and eosin.The levels of tumor necrosis factor (TNF)-o,interleukin (IL)-1β,and IL-6 in the flap samples were measured.Results Surviving flap size was significantly higher in the HBO preconditioning group compared with controls,with a reduced inflammatory response and increased perfusion.IL-1,TNF-α,and IL-6 levels in the HBO preconditioning group were lower than in controls.Conclusions HBO preconditioning improved flap survival in this ischemia-reperfusion rat model.The mechanisms responsible for this effect may relate to attenuation of the inflammatory response and increased flap perfusion following HBO preconditioning.

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

    Science.gov (United States)

    Usherwood, James Richard

    2016-11-01

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

  18. 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...... control 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....... code HAWC2. The investigated smart rotor configuration mainly aims at alleviating the fatigue loads the turbine rotor has to withstand during normal operation. First, the characteristics of the prevailing loads are identified; then, two model-based control algorithms are outlined: the algorithms...

  19. 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...

  20. PIV Measurements on a Blowing Flap

    Science.gov (United States)

    Hutcheson, Florence V.; Stead, Daniel J.

    2004-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  2. Chlorogenic Acid Enhances Abdominal Skin Flap Survival Based on Epigastric Artery in Nondiabetic and Diabetic Rats.

    Science.gov (United States)

    Bagdas, Deniz; Etoz, Betul Cam; Gul, Zulfiye; Ozyigit, Musa Ozgur; Cinkilic, Nilufer; Inan, Sevda; Buyukcoskun, Naciye Isbil; Ozluk, Kasim; Gurun, Mine Sibel

    2016-08-01

    Previous studies showed that chlorogenic acid (CGA) accelerates wound healing via its antioxidant activity. We aimed to investigate the effect of CGA in an experimental epigastric abdominal skin flap model in nondiabetic and diabetic rats. Rats were firstly divided into 2 groups: nondiabetic and diabetic. Diabetes was induced by streptozotocin. Then, 4 subgroups were created for each group: vehicle as well as 0.2 mg/0.5 mL, 1 mg/0.5 mL, and 5 mg/0.5 mL CGA treatments. Right epigastric artery-based abdominal skin flaps were elevated and sutured back into their original position. Chlorogenic acid or vehicle was injected once into the femoral arteries by leaving the epigastric artery as the single artery feeding the flaps during the injection. On postoperative day 7, flap survivals were evaluated, and the rats were killed. Distal flap tissues were collected for histopathological and biochemical assays. Chlorogenic acid showed greater flap survival in both nondiabetic and diabetic rats. Capillary density was increased, and necrosis was reduced in the CGA-treated rats. Chlorogenic acid decreased malondialdehyde levels as well as increased reduced glutathione and superoxide dismutase levels in the flap tissues. This study showed that CGA significantly improved flap survival by its antioxidant activities with intra-arterial local injections. PMID:25356637

  3. Active flow control over a backward-facing step using plasma actuation

    Science.gov (United States)

    Ruisi, R.; Zare-Behtash, H.; Kontis, K.; Erfani, R.

    2016-09-01

    Due to the more stringent aviation regulations on fuel consumption and noise reduction, the interest for smaller and mechanically less complex devices for flow separation control has increased. Plasma actuators are currently among the most studied typology of devices for active flow control purposes due to their small size and lightweight. In this study, a single dielectric barrier discharge (SDBD) actuator is used on a backward-facing step to assess its effects on the separated turbulent shear layer and its reattachment location. A range of actuating modulation frequencies, related to the natural frequencies of shear layer instability (flapping) and vortex shedding instability, are examined. The particle image velocimetry technique is used to analyse the flow over the step and the reattachment location. The bulk-flow experiments show negligible effects both on the shear layer and on the reattachment location for every frequency considered, and the actuator is not able to induce a sufficient velocity increase at the step separation point.

  4. 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

  5. Interaction of Two Flapping Flags in Axial Flow

    Science.gov (United States)

    Gunter, Amy-Lee; Fayed, Mohamed; Abderrahmane, Hamid Ait; Paidoussis, Michael P.; Ng, Hoi Dick

    2010-11-01

    The flapping of two parallel flags in axial low turbulence flow is investigated experimentally inside a small scale wind tunnel test section. The variables of the problem are the size and flexural rigidity of the flags, and the distance that separates the two flags. The flow velocity represents the control parameter that governs the coupling and flapping mode of the flags. Two flapping modes, in-phase and out-of-phase modes, were observed in the experiment. Image processing technique was used and the time series of a given point on the flag edge was analyzed. The stability condition of the flags was obtained and compared to the recent theoretical models. The dynamics of the coupling between the two flags is also studied.

  6. An Experimental Investigation on Flapping Flexible Membrane Wings

    Science.gov (United States)

    Hu, Hui; Abate, Gregg; Albertani, Roberto

    2008-11-01

    Thin and flexible membrane wings are unique to flying and gliding mammals, such as bats, flying squirrels and sugar gliders. These animals exhibit extraordinary flight capabilities with respect to maneuvering and agility that are not observed in other species of comparable size. In this study, comprehensive wind tunnel experiments are conducted to assess the effects of membrane flexibility (rigidity) on the aerodynamic performance of the flapping flexible membrane wings to quantify the benefits of using flexible membrane wings compared with conventional rigid wings for flapping-wing Micro-Air-Vehicle (MAV) applications. The present study is conducted from the viewpoint of aerospace engineers to try to leverage the unique feature of flexible membrane airfoils/wings found in bats and other flying/gliding mammals as an effective aerodynamic control method to explore the potential applications of such non-traditional, bio-inspired flexible membrane wings to flapping-wing MAVs to improve their flight agility and maneuverability.

  7. 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.

  8. Interactions between butterfly scales and unsteady flows during flapping flight

    Science.gov (United States)

    Jones, Robert; Lang, Amy

    2008-11-01

    Recent research has shown that the highly flexible wings of butterflies in flapping flight develop vortices along their leading and trailing edges. Butterfly scales (approximately 100 microns) have a shingled pattern and extend into the boundary layer. These scales could play a part in controlling separation in this 3-dimensional complex flow field. Biomimetic applications of butterfly scales may aid in the development of flapping wing micro air vehicles. In this study, we observed that the orientation of the scales may relate to the local flow field, and might move or shift during flight. Monarch butterflies were trained to fly in a low speed smoke tunnel for visualization. Scales were removed from the leading and trailing edges and specimens were photographed at 500 frames per second. Variation in flapping pattern and flight fitness are discussed.

  9. Management of osteoradionecrosis of the mandible with myocutaneous flaps

    International Nuclear Information System (INIS)

    Involvement of large areas of the mandible or the entire mandible with osteoradionecrosis may result in severe functional disability and cosmetic deformity. The use of a well-vascularized pectoralis major myocutaneous flap from outside the original field of irradiation has been successful in obtaining functional and cosmetic goals. Myocutaneous flaps provide bulk for contour and tissue support, and their rich vascular supply promotes healing of the heavily irradiated soft tissue and bone. Successful bone grafting for mandibular reconstruction may follow control of the osteoradionecrosis

  10. Unsteady vortex-dominated flow around wings with oscillating leading-edge flaps

    Science.gov (United States)

    Kandil, Osama A.; Salman, Ahmed A.

    1991-01-01

    Unsteady vortex-dominated flow around delta wings with oscillating leading-edge flaps represents an important classs of problems for supermaneuverability and flow control of advanced aircraft. The problem is solved using time accurate integration of the unsteady, compressible, thin-layer Navier-Stokes equations in conjunction with the unsteady, linearized, Navier-displacement equations. Starting with an initial configuration of the wing and its flaps, the Navier-Stokes equations are solved on an initial structured grid for the steady flow. The forced oscillation of the flaps is then applied, and the problem is solved accurately in time. The Navier-displacement equations are solved for the grid deformation and the Navier-Stokes equations are solved for the flowfield. Symmetric and anti-symmetric flaps oscillations are presented to study the effect of the flaps oscillation on the leading-edge vortical flow.

  11. 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 < 0.001, respectively) significantly higher in comparison to the control group. The histopathological analysis has revealed a lower degree of hyalinization, degenerated muscle fibers and nuclear change in the 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. PMID:26950289

  12. 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 steady-l

  13. Jet-Engine Exhaust Nozzle With Thrust-Directing Flaps

    Science.gov (United States)

    Wing, David J.

    1996-01-01

    Convergent/divergent jet-engine exhaust nozzle has cruciform divergent passage containing flaps that move to deflect flow of exhaust in either or both planes perpendicular to main fore-and-aft axis of undeflected flow. Prototype of thrust-vector-control nozzles installed in advanced, high-performance airplanes to provide large pitching (usually, vertical) and yawing (usually, horizontal) attitude-control forces independent of attitude-control forces produced by usual aerodynamic control surfaces.

  14. Active interaction control for civil structures

    OpenAIRE

    Wang, Luo-Jia

    1997-01-01

    This thesis presents a civil engineering approach to active control for civil structures. The proposed control technique, termed Active Interaction Control (AIC), utilizes dynamic interactions between different structures, or components of the same structure, to reduce the resonance response of the controlled or primary structure under earthquake excitations. The primary control objective of AIC is to minimize the maximum story drift of the primary structure. This is accomplished by timing th...

  15. AdVEGF-All6A+ Preconditioning of Murine Ischemic Skin Flaps Is Comparable to Surgical Delay

    OpenAIRE

    Gersch, Robert P.; Fourman, Mitchell S.; Phillips, Brett T.; Nasser, Ahmed; McClain, Steve A.; Khan, Sami U.; Dagum, Alexander B.; Bui, Duc T.

    2015-01-01

    Background: Surgical flap delay is commonly used in preconditioning reconstructive flaps to prevent necrosis. However, staged procedures are not ideal. Pharmacologic up-regulation of angiogenic and arteriogenic factors before flap elevation poses a nonsurgical approach to improve flap survival. Methods: Male Sprague Dawley rats were divided into control (n = 16), surgical delay (Delay), AdNull, AdEgr-1, and AdVEGF (n ≥ 9/group) groups. Delay rats had a 9 cm × 3 cm cranial based pedicle skin f...

  16. 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

  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. Internal Mammary Artery Perforator flap

    NARCIS (Netherlands)

    Schellekens, P.P.A.

    2012-01-01

    Reconstructive surgery evolved as a result of the enormous numbers of World War I and II victims, long before profound knowledge of the vascularity of flaps was present. Sophisticated imaging techniques have given us at present a thorough understanding of the vascularity of tissues so that randomly

  19. Critical Appraisal of Nasolabial Flap for Reconstruction of Oral Cavity Defects in Cancer Patients

    International Nuclear Information System (INIS)

    Purpose: Re-evaluation of nasolabial flap in lip and oral cavity reconstruction and role of each of its variants in reconstructing various intermediate size defects was addressed. Patients and Methods: Case-series study was con-ducted in National Cancer Institute, Cairo University over the period from July 2005 - January 2009 which included 23 patients with clinically T-l N0, T-2 N0 invasive squamous cell carcinoma of buccal mucosa and the vermilion border of the lower lip. Immediately after surgical excision, one stage reconstruction of the defect was done using a type of nasolabial flap. All patients were followed and the median follow-up period was 7.5 month. Results: Twelve patients with the lower lip carcinoma and 11 patients with the carcinoma of buccal mucosa underwent surgical excision under frozen section control. 19 fasciocutaneous nasolabial flap and 4 facial artery musculomucosal flaps were used for reconstruction. Minor wound complications occurred in 2 flaps and one patient required secondary suture. Flap viability was reliable and was not affected by performance of a synchronous neck dissection. Functional results were satisfactory, cosmetic results were good in most of the patients and excellent when facial artery musculomucosal flap was used. Conclusion: The nasolabial flap is a reliable and minimally traumatic local flap for one stage reconstruction of medium size defects in the oral cavity. The abundant blood supply allowed its modification in order to cover larger defects or to obtain better cosmetic results. This versatility makes it more widely used thus minimizing the use of local tongue flaps and split thickness grafts for covering these medium size defects in cases of buccal mucosa cancer or affecting the other lip or commissure in cases of lip cancer. It has a high viability rate, low complication rate; it is quick and easy to perform in addition to its satisfactory functional and cosmetic results.

  20. Investigation of the Effectiveness of Boundary-layer Control by Blowing over a Combination of Sliding and Plain Flaps in Deflecting a Propeller Slipstream Downward for Vertical Take-off

    Science.gov (United States)

    Spreemann, Kenneth P; Kuhn, Richard E

    1956-01-01

    An investigation was conducted in order to determine the effectiveness of blowing a jet of air over the flaps of a wing equipped with a 50-percent-chord sliding flap and a 25-percent-chord plain flap in deflecting a propeller slipstream downward for vertical take-off and the results are presented herein. The effects of a leading-edge slat, ground proximity, end plate, and propeller position were also investigated. The tests were conducted in a static-thrust facility at the Langley Aeronautical Laboratory.

  1. Microglial control of neuronal activity

    Directory of Open Access Journals (Sweden)

    Catherine eBéchade

    2013-03-01

    Full Text Available Fine-tuning of neuronal activity was thought to be a neuron-autonomous mechanism until the discovery that astrocytes are active players of synaptic transmission. The involvement of astrocytes has changed our understanding of the roles of non-neuronal cells and shed new light on the regulation of neuronal activity. Microglial cells are the macrophages of the brain and they have been mostly investigated as immune cells. However recent data discussed in this review support the notion that, similarly to astrocytes, microglia are involved in the regulation of neuronal activity. For instance, in most, if not all, brain pathologies a strong temporal correlation has long been known to exist between the pathological activation of microglia and dysfunction of neuronal activity. Recent studies have convincingly shown that alteration of microglial function is responsible for pathological neuronal activity. This causal relationship has also been demonstrated in mice bearing loss-of-function mutations in genes specifically expressed by microglia. In addition to these long-term regulations of neuronal activity, recent data show that microglia can also rapidly regulate neuronal activity, thereby acting as partners of neurotransmission.

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

    International Nuclear Information System (INIS)

    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

  3. 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.

  4. 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.

  5. 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,…

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

    Science.gov (United States)

    Lewin, Gregory Carl

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

  7. 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.

  8. Formation of a reliable capsular flap in a rat model.

    NARCIS (Netherlands)

    Schuringa, M.C.; Hartman, E.H.M.; Ruhe, P.Q.; Jansen, J.A.; Spauwen, P.H.M.

    2007-01-01

    Prefabrication can be used to produce capsular flaps; other researchers have confirmed the feasibility of such flaps. Before the possibilities of capsular flaps can be explored, a reliable method to create these flaps has to be established first. METHODS: To produce capsular flaps in a rat model, th

  9. Drag and lift reduction of a 3D bluff body using flaps

    Energy Technology Data Exchange (ETDEWEB)

    Beaudoin, Jean-Francois [PSA Peugeot-Citroen, Research and Innovation Department, Velizy-Villacoublay, FR (France); Aider, Jean-Luc [PSA Peugeot-Citroen, Research and Innovation Department, Velizy-Villacoublay, FR (France); Laboratoire PMMH, ESPCI, Paris cedex 05 (France)

    2008-04-15

    We present an experimental study on flow control over a classic 3D bluff-body used in automotive aerodynamics (Ahmed 1983). Flow control is achieved through moving flaps fixed on every edge around the two rear flat surfaces of the model. Different pairs of flaps, with variable angle compared to the walls, are tested. Parametric studies show that the most efficient configuration for the flaps is along the side edges of the rear slant, i.e. in the region where longitudinal vortices are created, and also at the junction between the roof and the rear slant, where the flow separates. We also explore the combinations of different flap configurations. We find interesting results showing cumulative effects between some configurations leading to -25% drag reduction and -105% lift reduction. Finally, particle image velocimetry measurements show that one of the key effects is the control of the longitudinal vortices created at the side edges of the rear slant. (orig.)

  10. An Improved Production Activity Control Architecture for Shop Floor Control

    Institute of Scientific and Technical Information of China (English)

    SHAHIDIkramullahButt; SUNHou-fang; HAMIDUllahKhanNiazi

    2005-01-01

    This paper presents a further improved Production Activity Control Architecture to deal with the complexity of information by creating Sub-Producers and Sub-Movers which will not only give a better control at workstation level but also reduce load on the Dispatcher. It also makes an analysis of the basic and improved PAC (Production Activity Control) Architecture in the Control System for Integrated Manufacturing. The PAC Architecture and the improvement will further enhance the flexibility and adaptability of the architecture in the ever changing environment of the Shop Floor Control (SFC) Systems.

  11. 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.

  12. Wind tunnel investigation of a high lift system with pneumatic flow control

    Science.gov (United States)

    Victor, Pricop Mihai; Mircea, Boscoianu; Daniel-Eugeniu, Crunteanu

    2016-06-01

    Next generation passenger aircrafts require more efficient high lift systems under size and mass constraints, to achieve more fuel efficiency. This can be obtained in various ways: to improve/maintain aerodynamic performance while simplifying the mechanical design of the high lift system going to a single slotted flap, to maintain complexity and improve the aerodynamics even more, etc. Laminar wings have less efficient leading edge high lift systems if any, requiring more performance from the trailing edge flap. Pulsed blowing active flow control (AFC) in the gap of single element flap is investigated for a relatively large model. A wind tunnel model, test campaign and results and conclusion are presented.

  13. 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 desir

  14. Adjoint-based optimization of flapping plates hinged with a trailing-edge flap

    Directory of Open Access Journals (Sweden)

    Min Xu

    2015-01-01

    Full Text Available It is important to understand the impact of wing-morphing on aerodynamic performance in the study of flapping-wing flight of birds and insects. We use a flapping plate hinged with a trailing-edge flap as a simplified model for flexible/morphing wings in hovering. The trailing-edge flapping motion is optimized by an adjoint-based approach. The optimized configuration suggests that the trailing-edge flap can substantially enhance the overall lift. Further analysis indicates that the lift enhancement by the trailing-edge flapping is from the change of circulation in two ways: the local circulation change by the rotational motion of the flap, and the modification of vortex shedding process by the relative location between the trailing-edge flap and leading-edge main plate.

  15. 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

  16. Automobile active suspension system with fuzzy control

    Institute of Scientific and Technical Information of China (English)

    刘少军; 黄中华; 陈毅章

    2004-01-01

    A quarter-automobile active suspension model was proposed. High speed on/off solenoid valves were used as control valves and fuzzy control was chosen as control method . Based on force analyses of system parts, a mathematical model of the active suspension system was established and simplified by linearization method. Simulation study was conducted with Matlab and three scale coefficients of fuzzy controller (ke, kec, ku) were acquired. And an experimental device was designed and produced. The results indicate that the active suspension system can achieve better vibration isolation performance than passive suspension system, the displacement amplitude of automobile body can be reduced to 55%. Fuzzy control is an effective control method for active suspension system.

  17. 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...

  18. Root coverage with bridge flap

    Directory of Open Access Journals (Sweden)

    Pushpendra Kumar Verma

    2013-01-01

    Full Text Available Gingival recession in anterior teeth is a common concern due to esthetic reasons or root sensitivity. Gingival recession, especially in multiple anterior teeth, is of huge concern due to esthetic reasons. Various mucogingival surgeries are available for root coverage. This case report presents a new bridge flap technique, which allows the dentist not only to cover the previously denuded root surfaces but also to increase the zone of attached gingiva at a single step. In this case, a coronally advanced flap along with vestibular deepening technique was used as root coverage procedure for the treatment of multiple recession-type defect. Here, vestibular deepening technique is used to increase the width of the attached gingiva. The predictability of this procedure results in an esthetically healthy periodontium, along with gain in keratinized tissue and good patient′s acceptance.

  19. SLIDING MODE CONTROL FOR ACTIVE AUTOMOBILE SUSPENSIONS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Nonlinear control methods are presented based on theory of sliding mode control (SMC) or variable structure control (VSC) for application to active automobile suspensions. Requirements of reducing manufacturing cost and energy consumption of the active suspension system may be satisfiedby reasonable design of the sliding surface and hydraulic servo system. Emphasis is placed on the study of the discrete sliding mode control method (DSMC) applicable for a new sort of speed on-off solenoid valves of anti-dust capability and low price. Robustness and effectiveness of the feedback linearized controller in typical road conditions are demonstrated by numerical results fora quarter-car suspension model.

  20. Inferior Gluteal Perforator Flaps for Breast Reconstruction

    OpenAIRE

    Allen, Robert J.; LoTempio, Maria M.; Granzow, Jay W.

    2006-01-01

    Perforator flaps represent the latest in the evolution of soft tissue flaps. They allow the transfer of the patient's own skin and fat in a reliable manner with minimal donor-site morbidity. The powerful perforator flap concept allows transfer of tissue from numerous, well-described donor sites to almost any distant site with suitable recipient vessels. The inferior gluteal artery perforator (I-GAP) flap is one option that allows a large volume of tissue to be used for breast reconstruction w...

  1. Optimal propulsive flapping in Stokes flows

    CERN Document Server

    Was, Loic

    2014-01-01

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

  2. Basic Perforator Flap Hemodynamic Mathematical Model

    Science.gov (United States)

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

    2016-01-01

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

  3. 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.)

  4. Structural integrated sensor and actuator systems for active flow control

    Science.gov (United States)

    Behr, Christian; Schwerter, Martin; Leester-Schädel, Monika; Wierach, Peter; Dietzel, Andreas; Sinapius, Michael

    2016-04-01

    An adaptive flow separation control system is designed and implemented as an essential part of a novel high-lift device for future aircraft. The system consists of MEMS pressure sensors to determine the flow conditions and adaptive lips to regulate the mass flow and the velocity of a wall near stream over the internally blown Coanda flap. By the oscillating lip the mass flow in the blowing slot changes dynamically, consequently the momentum exchange of the boundary layer over a high lift flap required mass flow can be reduced. These new compact and highly integrated systems provide a real-time monitoring and manipulation of the flow conditions. In this context the integration of pressure sensors into flow sensing airfoils of composite material is investigated. Mechanical and electrical properties of the integrated sensors are investigated under mechanical loads during tensile tests. The sensors contain a reference pressure chamber isolated to the ambient by a deformable membrane with integrated piezoresistors connected as a Wheatstone bridge, which outputs voltage signals depending on the ambient pressure. The composite material in which the sensors are embedded consists of 22 individual layers of unidirectional glass fiber reinforced plastic (GFRP) prepreg. The results of the experiments are used for adapting the design of the sensors and the layout of the laminate to ensure an optimized flux of force in highly loaded structures primarily for future aeronautical applications. It can be shown that the pressure sensor withstands the embedding process into fiber composites with full functional capability and predictable behavior under stress.

  5. Use of preoperative ultrasound in designing the true pectoralis major myocutaneous island flap

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-hong; ZHAO Han-xue; FANG Ju-gao; YU Zhen-kun; HUANG Zhi-gang

    2012-01-01

    Background Traditional techniques used for harvesting the pectoralis major myocutaneous (PMMC) flap have accompanying disadvantages,such as the necessity for an upper chest skin incision,the bulkiness of myocutaneous tissue at the pedicle of the flap,and the risk of total or partial necrosis of flap tissue.The aim of this study was to develop a safe and fast method for preparing PMMC island flaps using preoperative ultrasonography for vessel detection.Methods Forty-one PMMC island flaps were used for one-stage reconstruction of head and neck defects,including 21 cases in the treatment group and 20 cases in the control group.In the treatment group,ultrasonography was used to mark out the course of the thoracic branches of the thoracoacromial artery and the lower end of this artery perforating from the fascia into the muscles,as well as the largest perforating branch of the fourth or fifth internal mammary artery entering the PMMC flap.A line,from the lower end of the thoracic branch to the largest perforating branch of the fourth or fifth internal mammary artery,was drawn to determine the axis of the PMMC flap.In the control group,PMMC island flaps were designed according to conventional methods without using ultrasonography.Results According to the ultrasonic marks,the distance from lower end of thoracic branch to the midpoint of the margin of the inferior clavicular was (5.1±1.2) cm.The time from designing to transferring the island flap was significantly shorter in the treatment group ((51.0±10.5) minutes) compared with the control group ((78.0±13.9) minutes,P <0.01).The rate of partial necrosis was 4.7% (1/21) in the treatment group and 35.0% (7/20) in the control group.There was one case of flap failure in the control group due to vascular injury during vascular pedicle dissection.Conclusion Preoperative vessel detection by ultrasonography facilitates easy and safe harvesting of the true PMMC island flap.

  6. Active Control of Fan Noise

    Institute of Scientific and Technical Information of China (English)

    Nobuhiko YAMASAKI; Hirotoshi TAJIMA

    2008-01-01

    In the wake-rotor interaction fan noise, a number of the interacting modes at the blade passing frequency (BPF)and its harmonics are generated which are prescribed by the number of stator and rotor blades etc. In the present study, the dominant mode is tried to be suppressed by the secondary sound from the loudspeaker actuators. One of the novel features of the present system is the adoption of the control board with the Field Programmable Gate Array (FPGA) hardware and the LabVIEW software to synchronize the circumferentially installed loudspeaker actuators with the relative location of rotational blades under arbitrary fan rotational speeds. The experiments were conducted under the conditions of three rotational speeds of 2004, 3150, and 4002 [rpm]. The reduction in the sound pressure level (SPL) was observed for all three rotational speeds. The sound pressure level at the BPF was reduced approximately 13 [dB] for 2004 [rpm] case, but not so large reduction was attained for other cases probably due to the inefficiency of the loudspeaker actuators at high frequencies

  7. Active vibration control of lightweight floor systems

    Science.gov (United States)

    Baader, J.; Fontana, M.

    2016-04-01

    Wide-span and lightweight floors are often prone to structural vibrations due to their low resonance frequency and poor material damping. Their dynamic behaviour can be improved using passive, semi-active or active vibration control devices. The following article proposes a novel method for the controller synthesis for active vibration control. An existing passive TMD (tuned mass damper) is modelled and equipped with an actuator in order to provide more efficient damping. Using an iterative optimization approach under constraints, an optimal controller is found which minimizes a quadratic cost function in frequency domain. A simulation of an existing test bench shows that the active vibration control device is able to provide increased damping compared to the passive TMD.

  8. Toward the bi-modal camber morphing of large aircraft wing flaps: the CleanSky experience

    Science.gov (United States)

    Pecora, R.; Amoroso, F.; Magnifico, M.

    2016-04-01

    The Green Regional Aircraft (GRA), one of the six CleanSky platforms, represents the largest European effort toward the greening of next generation air transportation through the implementation of advanced aircraft technologies. In this framework researches were carried out to develop an innovative wing flap enabling airfoil morphing according to two different modes depending on aircraft flight condition and flap setting: - Camber morphing mode. Morphing of the flap camber to enhance high-lift performances during take-off and landing (flap deployed); - Tab-like morphing mode. Upwards and downwards deflection of the flap tip during cruise (flap stowed) for load control at high speed and consequent optimization of aerodynamic efficiency. A true-scale flap segment of a reference aircraft (EASA CS25 category) was selected as investigation domain for the new architecture in order to duly face the challenges posed by real wing installation issues especially with reference to the tapered geometrical layout and 3D aerodynamic loads distributions. The investigation domain covered the flap region spanning 3.6 m from the wing kink and resulted characterized by a taper ratio equal to 0.75 with a root chord of 1.2 m. High TRL solutions for the adaptive structure, actuation and control system were duly analyzed and integrated while assuring overall device compliance with industrial standards and applicable airworthiness requirements.

  9. 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.

  10. Manually controlled neutron-activation system

    Science.gov (United States)

    Johns, R. A.; Carothers, G. A.

    1982-01-01

    A manually controlled neutron activation system, the Manual Reactor Activation System, was designed and built and has been operating at one of the Savannah River Plant's production reactors. With this system, samples can be irradiated for up to 24 hours and pneumatically transferred to a shielded repository for decay until their activity is low enough for them to be handled at a radiobench. The Manual Reactor Activation System was built to provide neutron activation of solid waste forms for the Alternative Waste Forms Leach Testing Program. Neutron activation of the bulk sample prior to leaching permits sensitive multielement radiometric analyses of the leachates.

  11. 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)

  12. [The super extended sub-mental flap or combo sub-mental flap].

    Science.gov (United States)

    Martin, D

    2014-08-01

    The author presents a technical variation of the sub-mental flap including in a conventional pedicled flap both sub-mental axes and their anastomoses on the midline. The assessment of the first flaps raised according to this method confirms the improvement of the distal blood supply. It allows the possibility to harvest "super extended" flaps reaching the contralateral auricular lobula. This variation can be considered as an axial flap which only the tip, located beyond the mandibular angle, is at random. The evolution of the sub-mental flap from its original description to this variation called "combo sub-mental flap" is then presented. Its reliability and the technical simplification it provides will have to be assessed in the future. PMID:24840945

  13. Secondary onlay free flap reconstruction of glossectomy defects following initial successful flap restoration.

    Science.gov (United States)

    Rihani, Jordan; Lee, Thomas; Ducic, Yadranko

    2013-08-01

    Patients who undergo tongue reconstruction over time may develop gradual worsening of dysarthria and dysphagia secondary to flap atrophy. At our institution, these patients undergo a secondary flap onlay procedure for augmentation of the neotongue. We review a total of 11 patients with total glossectomy defect who underwent secondary tongue augmentation with secondary onlay free flap consisting of radial forearm free flap (n = 6) and rectus free flap (n = 5). There was improvement in swallowing in 7 of 11 patients. Five (45.4%) patients achieved gastric tube independence. Seven (63.6%) patients achieved a varying degree of oral intake. All patients achieved tracheostomy independence. Dysarthria was improved in all patients. There were no flap failures. Therefore, a secondary onlay flap technique is feasible and may improve dysphagia and dysarthria to achieve gastric tube and tracheostomy independence in total glossectomy patients with delayed tongue atrophy. PMID:23625797

  14. Cheek-neck advancement-rotation flaps following Mohs excision of skin malignancies.

    Science.gov (United States)

    Katz, A E; Grande, D J

    1986-09-01

    The cheek-neck advancement-rotation flap has proved extremely useful for delayed reconstruction of the face following the microscopically controlled surgical excision (MCSE) of skin malignancies. We have recently used these flaps successfully to repair combined defects of the cheek and nose in eight patients, isolated cheek defects in six patients, combined defects of the cheek and lips in two patients, and isolated defects of the nose, temple, and an antral cutaneous fistula in each of three patients. Defects as large as 6.0 X 10.0 cm have been closed in one stage with this flap. This flap is extremely hearty and its scars can be well concealed. It is especially valuable in the elderly patient and should always be considered as one of the options for reconstruction of the face following MCSE of skin malignancies. PMID:3745621

  15. Active Noise Control in Propeller Aircraft

    OpenAIRE

    Johansson, Sven; Claesson, Ingvar

    2001-01-01

    A noisy environment dominated by low frequency noise can often be improved through the use of active noise control. This situation arises naturally in propeller aircraft where the propellers induce periodic low frequency noise inside the cabin. The cabin noise is typically rather high, and the passenger flight comfort could be improved considerably if this level were significantly reduced. This paper addresses same design aspects for multiple-reference active noise control systems based on th...

  16. 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.

  17. 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 object

  18. Prefabricated flaps for bone reconstructive surgery

    NARCIS (Netherlands)

    Hartman, E.H.M.

    2004-01-01

    Tissue engineering of bone could help minimise donor site defects of conventional bone flaps like the fibula, iliac crest, radius and scapula. First a review is given on the literature of donor site morbidity of these flaps. Then the use of MRI is investigated for longitudinal study of ectopic bone

  19. Semi-active control of dynamically excited structures using active interaction control

    OpenAIRE

    Zhang, Yunfeng

    2001-01-01

    This thesis presents a family of semi-active control algorithms termed Active Interaction Control (AIC) used for response control of dynamically excited structures. The AIC approach has been developed as a semi﷓active means of protecting building structures against large earthquakes. The AIC algorithms include the Active Interface Damping (AID), Optimal Connection Strategy (OCS), and newly developed Tuned Interaction Damping (TID) algorithms. All of the AIC algorithms are founded upon ...

  20. Classifying controllers by activities : An exploratory study

    NARCIS (Netherlands)

    Verstegen, B.; De Loo, I.G.M.; Mol, P.; Slagter, K.; Geerkens, H.

    2007-01-01

    The goal of this paper is to discern variables (triggers) that affect a controller’s role in an organisation. Using survey data, groups of controllers are distinguished based on coherent combinations of activities. We find that controllers either operate as so-called ‘information adapters’ or ‘watch

  1. Active control of vibrations in pedestrian bridges

    OpenAIRE

    Álvaro Cunha; Carlos Moutinho

    1999-01-01

    This paper, apart from making a brief general reference to vibration problems in pedestrian bridges, as well as to the form of modelling of dynamic pedestrian loads, presents the use of a predictive control strategy for the numerical simulation of the dynamic response of actively controlled structures of this type. The consideration of this control strategy permitted the development of a computational model, which was applied to the study of a pedestrian cable-stayed bridge, in order to show ...

  2. Active and passive vibration control of structures

    CERN Document Server

    Spelsberg-Korspeter, Gottfried

    2014-01-01

    Active and Passive Vibration Control of Structures form an issue of very actual interest in many different fields of engineering, for example in the automotive and aerospace industry, in precision engineering (e.g. in large telescopes), and also in civil engineering. The papers in this volume bring together engineers of different background, and it fill gaps between structural mechanics, vibrations and modern control theory.  Also links between the different applications in structural control are shown.

  3. Piezoelectrically actuated insect scale flapping wing

    Science.gov (United States)

    Mukherjee, Sujoy; Ganguli, Ranjan

    2010-04-01

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

  4. Fasciocutaneous flap for vaginal and perineal reconstruction

    International Nuclear Information System (INIS)

    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

  5. 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.

  6. 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...

  7. Control of nucleus accumbens activity with neurofeedback

    OpenAIRE

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

    2014-01-01

    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 pres...

  8. Active aerodynamic stabilisation of long suspension bridges

    DEFF Research Database (Denmark)

    Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

    2004-01-01

    The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to ma...

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

    DEFF Research Database (Denmark)

    Bergami, Leonardo

    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...... 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...... 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....

  10. 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...... 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...... 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...

  11. 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.

  12. Pudendal thigh flap for repair of rectovaginal fistula.

    Science.gov (United States)

    Sathappan, S; Rica, M A I

    2006-08-01

    The pudendal thigh flap or the Singapore flap is a versatile flap that can be used in the repair of recto-vaginal fistulae. Apart from the potential problem of hair growth, this neurovascular flap proves to be surprisingly simple in technique, robust and has a high potential for normal or near-normal function. PMID:17240589

  13. 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.

  14. 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.

  15. Adaptive Piezoelectric Absorber for Active Vibration Control

    Directory of Open Access Journals (Sweden)

    Sven Herold

    2016-02-01

    Full Text Available Passive vibration control solutions are often limited to working reliably at one design point. Especially applied to lightweight structures, which tend to have unwanted vibration, active vibration control approaches can outperform passive solutions. To generate dynamic forces in a narrow frequency band, passive single-degree-of-freedom oscillators are frequently used as vibration absorbers and neutralizers. In order to respond to changes in system properties and/or the frequency of excitation forces, in this work, adaptive vibration compensation by a tunable piezoelectric vibration absorber is investigated. A special design containing piezoelectric stack actuators is used to cover a large tuning range for the natural frequency of the adaptive vibration absorber, while also the utilization as an active dynamic inertial mass actuator for active control concepts is possible, which can help to implement a broadband vibration control system. An analytical model is set up to derive general design rules for the system. An absorber prototype is set up and validated experimentally for both use cases of an adaptive vibration absorber and inertial mass actuator. Finally, the adaptive vibration control system is installed and tested with a basic truss structure in the laboratory, using both the possibility to adjust the properties of the absorber and active control.

  16. Discrete tone noise on two-dimensional wing. Active control for discrete tone; Nijigen seishiyoku kara hasseisuru risan shuhasu soon no kenkyu. Risan shuhasu soon no nodo seigyo

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, S. [Mitsubishi Electric Corp., Tokyo (Japan); Akishita, S. [Ritsumeikan University, Kyoto (Japan). Faculty of Science and Engineering

    1996-01-25

    The active noise control of discrete tones generated in a uniform jet flow on a two-dimensional wing was investigated. Discrete tone noise is generated by a self-excited feedback loop formed by the acoustic field and the unstable boundary layer. In this work, we conducted an active control experiment using a flap driven by piezoceramic levers, which can vibrate with a phase delayed from the velocity fluctuation signal on the suction side. When the flap motion lags the pressure fluctuation at the trailing edge with a phase angle of 180 degrees, it was found that the discrete tone noise was reduced by a maximum of about 7 dB, the flow fluctuation intensities in the boundary layer on the suction side were reduced by about half, and the correlation area of the flow fluctuation at the trailing edge decreased. This confirms that discrete tone generation is caused by the feedback loop and that the discrete tone generation is actively reduced by trailing edge control. 10 refs., 14 figs.

  17. 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.

  18. 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.

  19. Aerodynamic characteristics of a wing with Fowler flaps including flap loads, downwash, and calculated effect on take-off

    Science.gov (United States)

    Platt, Robert C

    1936-01-01

    This report presents the results of wind tunnel tests of a wing in combination with each of three sizes of Fowler flap. The purpose of the investigation was to determine the aerodynamic characteristics as affected by flap chord and position, the air loads on the flaps, and the effect of flaps on the downwash.

  20. Actively Controlling Buffet-Induced Excitations

    Science.gov (United States)

    Moses, Robert W.; Pototzky, Anthony S.; Henderson, Douglas A.; Galea, Stephen C.; Manokaran, Donald S.; Zimcik, David G.; Wickramasinghe, Viresh; Pitt, Dale M.; Gamble, Michael A.

    2005-01-01

    High performance aircraft, especially those with twin vertical tails, encounter unsteady buffet loads when flying at high angles of attack. These loads result in significant random stresses, which may cause fatigue damage leading to restricted capabilities and availability of the aircraft. An international collaborative research activity among Australia, Canada and the United States, conducted under the auspices of The Technical Cooperation Program (TTCP) contributed resources toward a program that coalesced a broad range of technical knowledge and expertise into a single investigation to demonstrate the enhanced performance and capability of the advanced active BLA control system in preparation for a flight test demonstration. The research team investigated the use of active structural control to alleviate the damaging structural response to these loads by applying advanced directional piezoelectric actuators, the aircraft rudder, switch mode amplifiers, and advanced control strategies on an F/A-18 aircraft empennage. Some results of the full-scale investigation are presented herein.

  1. 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...

  2. Fibrin glue for Gundersen flap surgery

    Directory of Open Access Journals (Sweden)

    Chung HW

    2013-03-01

    Full Text Available Hsi-Wei Chung,1 Jodhbir S Mehta1–31Singapore National Eye Centre, Singapore; 2Tissue Engineering and Stem Cell Group, Singapore Eye Research Institute, Singapore; 3Department of Clinical Sciences, Duke-NUS Graduate Medical School, SingaporePurpose: To evaluate the feasibility of fibrin glue in Gundersen flap surgery.Design: Prospective case series.Study subjects: Seven eyes of seven subjects who had undergone Gundersen flap surgery from 2009 to 2011 at the Singapore National Eye Centre, Singapore.Methods: Review of case records for outcomes after Gundersen flap surgery.Main outcome measures: Surgical success was defined as achieving a stable ocular surface. Complications to be noted included flap retraction or exposure of underlying corneal surface.Results: Surgical success was achieved in all eyes with significant reduction in ocular surface inflammation. No retractions were noted and recovery was uncomplicated.Conclusion: Fibrin glue application is a viable alternative to sutures in Gundersen flap surgery. It reduces surgical downtime, gives faster ocular surface rehabilitation, and offers similar outcomes to conventional conjunctival flap surgery.Keywords: Gundersen, conjunctival flap, fibrin glue

  3. Use of Martius flap in the complex female urethral surgery

    OpenAIRE

    Kasyan, George; Tupikina, Nataliya; Pushkar, Dmitry

    2014-01-01

    Introduction Objectives were to evaluate safety and patient reported perception of the Martius fibroadipose flap for complex female urethra reconstruction. Material and methods Patients operated with a Martius flap were contacted again via telephone to rate their self–perception on cosmetic appearance, pain or numbness of the flap harvest site. Results 37 women (mean age of 46.8 yrs.) were operated with Martius flaps. Complications were limited to bleeding from the flap bed in 19% (7/37); hem...

  4. 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....

  5. 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.

  6. Active steering control strategy for articulated vehicles

    Institute of Scientific and Technical Information of China (English)

    Kyong-il KIM; Hsin GUAN; Bo WANG; Rui GUO; Fan LIANG

    2016-01-01

    To improve maneuverability and stability of articulated vehicles, we design an active steering controller, including tractor and trailer controllers, based on linear quadratic regulator (LQR) theory. First, a three-degree-of-freedom (3-DOF) model of the tractor-trailer with steered trailer axles is built. The simulated annealing particle swarm optimization (SAPSO) algorithm is applied to identify the key parameters of the model under specified vehicle speed and steering wheel angle. Thus, the key pa-rameters of the simplified model can be obtained according to the vehicle conditions using an online look-up table and interpola-tion. Simulation results show that vehicle parameter outputs of the simplified model and TruckSim agree well, thus providing the ideal reference yaw rate for the controller. Then the active steering controller of the tractor and trailer based on LQR is designed to follow the desired yaw rate and minimize their side-slip angle of the center of gravity (CG) at the same time. Finally, simulation tests at both low speed and high speed are conducted based on the TruckSim-Simulink program. The results show significant effects on the active steering controller on improving maneuverability at low speed and lateral stability at high speed for the articulated vehicle. The control strategy is applicable for steering not only along gentle curves but also along sharp curves.

  7. Span of Control and Span of Activity

    OpenAIRE

    Oriana Bandiera; Andrea Prat; Raffaella Sadun; Julie Wulf

    2012-01-01

    For both practitioners and researchers, span of control plays an important role in defining and understanding the role of the CEO. In this paper, we combine organizational chart information for a sample of 65 companies with detailed data on how their CEOs allocate their work time, which we define as their span of activity. Span of activity provides a direct measure of the CEO's management style, including the attention devoted to specific subordinates and functions, the time devoted to indivi...

  8. Capital Control, Debt Financing and Innovative Activity

    OpenAIRE

    Czarnitzki, Dirk; Kraft, Kornelius

    2009-01-01

    "The present paper discusses the effects of dispersed versus concentrated capital ownership on investment into innovative activity. While the market for equity capital might exert insufficient control on top managements’ behavior, this weakness may be mitigated by a suitable degree of debt financing. We report the results of an empirical study on the determinants of innovative activity measured by patent applications. Using a large sample of German manufacturing firms, we find that companies ...

  9. 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.

  10. Flap-augmented shrouds for aerogenerators

    Science.gov (United States)

    Seginer, A.

    1976-01-01

    Axisymmetrical shrouds for windmills are augmented by ring-shaped 'flaps' and their performance is studied experimentally. The concept of the shroud as an annular 'wing' is justified, leading to the conclusion that high-lift techniques should be used in shroud design, and that high-lift devices, such as flaps, would increase the power output of the windmill. It is shown experimentally that the ideal power output of a flap-augmented shrouded turbine can be more than 4 times the power of unshrouded turbines of the same diameter.

  11. Neural Anatomy of the Anterolateral Thigh Flap

    OpenAIRE

    Luenam, Suriya; Prugsawan, Krit; Kosiyatrakul, Arkaphat; Chotanaphuti, Thanainit; Sriya, Piyanee

    2015-01-01

    The anterolateral thigh (ALT) flap is one of the commonly used sensate flaps for intra-oral, hand, and foot reconstruction. The objective of this study was to describe the anatomic location of the sensory nerves supplying the ALT flap in relation to the surface landmarks and with the vascular pedicles. The dissections were carried out in 28 embalmed specimens. An axial line from the anterior superior iliac spine to the superolateral border of the patella and two circles with radii of 5 and 10...

  12. 大鼠腹壁浅动脉岛状皮瓣防护的研究%Research on a new method for protecting superficial epigastric artery island skin flaps in rats

    Institute of Scientific and Technical Information of China (English)

    张栋益; 康深松; 张正文; 吴蕊

    2015-01-01

    Objective To observe the protective effects of a protective clothing on rats' ischemia-reperfusion superficial epigastric artery (SIEA) flaps, which made of medical imaging film;explore new methods for fixing and protecting flaps.Methods Sixteen adult SD rats were randomly divided into 2 groups : control group (n =8), experimental group (n =8).A left low abdominal island flap which sized 6.0 cm × 3.0 cm and fed by the superficial epigastric artery was created in rats of all the 2 groups.Blocked the arterial blood flow by vascular clamps for 10 hours to establish Ischemia-reperfusion model of flaps.Rats in experimental group were fixed with a protective clothing but rats in control group not.The activities of rats, integrity and retraction degree of the flaps in each group were observed daily for 5 days.Results Observed flaps after 2, 3 and 5 days of the operation respectively, we found that the protective clothing was benefit to prevent rats bite flaps themselves and retraction of flaps without impacting basic activities of rats.Conclusion It is quite necessary for us to fix and protect SIEA flaps of rats when the ischemia-reperfusion models were made.The protective clothing made of medical imaging film effect significantly for preventing rats bite flaps themselves and retraction of flaps, and with simple fabrication process, which can be used as a new method to promote in animal experiments.%目的 观察医学影像胶片制作的一种防护罩对大鼠缺血再灌注腹壁浅动脉岛状皮瓣的防护作用.方法 将16只成年SD大鼠随机分成对照组、实验组,每组8只.各组大鼠于左侧腹部制备6cm×3cm腹壁浅动脉为蒂的岛状皮瓣,血管夹阻断皮瓣动脉血流10 h后恢复灌注制备皮瓣缺血再灌注动物模型,实验组大鼠以防护罩固定,对照组大鼠造模后不做外固定,模型制备完成后的5d内每天观察各组大鼠的活动、皮瓣的完整性及回缩程度.结果 各组

  13. Active Vibration Control of Piezolaminated Smart Beams

    Directory of Open Access Journals (Sweden)

    V. Balamurugan

    2001-04-01

    Full Text Available This paper deals with the active vibration control of beam like structures with distributed piezoelectric sensor and actuator layers bonded on top and bottom surfaces of the beam. A finite element model based on Euler-Bernoulli beam theory has been developed. The contribution of the piezoelectric sensor and actuator layers on the mass and stiffness of the beam is considered. Three types of classical control strategies, namely direct proportional feedback, constant-gain negative velocity feedback and Lyapunov feedback and an optimal control strategy, linear quadratic regulator (LQR scheme are applied to study their control effectiveness. Also, the control performance with different types of loading, such as impulse loading, step loading, harmonic and random loading is studied

  14. Propeller Flap Reconstruction in Post Oncological Thigh Defect: "The Move in Flap".

    Science.gov (United States)

    Nambi, G I; Salunke, Abhijeet Ashok

    2015-06-01

    Reconstruction of soft tissue defects of the limb after tumor resection is challenging question for oncosurgeons. The management differs from reconstruction of post traumatic defects due to the complexity of the primary surgery and subsequent radiation. The conventional propeller flap is based on a perforator which is located close to the defect; but in present case the perforator was located far away from the defect. So we describe it as "Move in flap" as the flap rotated a large volume of soft tissue lying between the defect and the perforator. We present a case of post oncological thigh defect with reconstruction using a propeller flap based on distal anteromedial perforator. PMID:26405422

  15. MODELING MERCURY CONTROL WITH POWDERED ACTIVATED CARBON

    Science.gov (United States)

    The paper presents a mathematical model of total mercury removed from the flue gas at coal-fired plants equipped with powdered activated carbon (PAC) injection for Mercury control. The developed algorithms account for mercury removal by both existing equipment and an added PAC in...

  16. DNA-based control of protein activity.

    Science.gov (United States)

    Engelen, W; Janssen, B M G; Merkx, M

    2016-03-01

    DNA has emerged as a highly versatile construction material for nanometer-sized structures and sophisticated molecular machines and circuits. The successful application of nucleic acid based systems greatly relies on their ability to autonomously sense and act on their environment. In this feature article, the development of DNA-based strategies to dynamically control protein activity via oligonucleotide triggers is discussed. Depending on the desired application, protein activity can be controlled by directly conjugating them to an oligonucleotide handle, or expressing them as a fusion protein with DNA binding motifs. To control proteins without modifying them chemically or genetically, multivalent ligands and aptamers that reversibly inhibit their function provide valuable tools to regulate proteins in a noncovalent manner. The goal of this feature article is to give an overview of strategies developed to control protein activity via oligonucleotide-based triggers, as well as hurdles yet to be taken to obtain fully autonomous systems that interrogate, process and act on their environments by means of DNA-based protein control. PMID:26812623

  17. Fatigue Test Technology of Slat and Flap with Active Driving and Servo Loading Device%一种主动驱动随动加载的前缘缝翼和襟翼疲劳试验技术

    Institute of Scientific and Technical Information of China (English)

    李小军; 陆慧莲; 李凯

    2014-01-01

    前缘缝翼、襟翼活动面及其支承结构的疲劳试验是民用飞机取证前要开展的一项重要工作。在试验中采用主动驱动和随动加载方法加载,不仅能缩小试验规模,同时可提高试验精度。国内某型机采用此技术成功进行了前缘缝翼、襟翼及其悬挂结构的疲劳试验。从试验件及其支承设计、系统构成和载荷与运行三方面,介绍了一种适用于大中型固定翼飞机前缘缝翼和襟翼的疲劳试验技术。%The fatigue tests on slat, flap and their supporting structures are very important work to be launched for a new airplane before technology certification ( TC) being granted. The loading which adopts active driving and ser-vo loading not only reduces the test scale but also enhances the test accuracy. This technology has been applied to make the fatigue test on some civil aircraft successfully. This paper presents the new fatigue test technology in three aspects:test article with its suspension, test system, load and implementation respectively.

  18. 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...

  19. 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

  20. Active control of multiple resistive wall modes

    International Nuclear Information System (INIS)

    A two-dimensional array of saddle coils at Mc poloidal and Nc toroidal positions is used on the EXTRAP T2R reversed-field pinch (Brunsell P R et al 2001 Plasma Phys. Control. Fusion 43 1457) to study active control of resistive wall modes (RWMs). Spontaneous growth of several RWMs with poloidal mode number m = 1 and different toroidal mode number n is observed experimentally, in agreement with linear MHD modelling. The measured plasma response to a controlled coil field and the plasma response computed using the linear circular cylinder MHD model are in quantitative agreement. Feedback control introduces a linear coupling of modes with toroidal mode numbers n, n' that fulfil the condition |n - n'| = Nc. Pairs of coupled unstable RWMs are present in feedback experiments with an array of Mc x Nc = 4 x 16 coils. Using intelligent shell feedback, the coupled modes are generally not controlled even though the field is suppressed at the active coils. A better suppression of coupled modes may be achieved in the case of rotating modes by using the mode control feedback scheme with individually set complex gains. In feedback with a larger array of Mc x Nc = 4 x 32 coils, the coupling effect largely disappears, and with this array, the main internal RWMs n = -11, -10, +5, +6 are all simultaneously suppressed throughout the discharge (7-8 wall times). With feedback there is a two-fold extension of the pulse length, compared to discharges without feedback

  1. Active control of multiple resistive wall modes

    Science.gov (United States)

    Brunsell, P. R.; Yadikin, D.; Gregoratto, D.; Paccagnella, R.; Liu, Y. Q.; Bolzonella, T.; Cecconello, M.; Drake, J. R.; Kuldkepp, M.; Manduchi, G.; Marchiori, G.; Marrelli, L.; Martin, P.; Menmuir, S.; Ortolani, S.; Rachlew, E.; Spizzo, G.; Zanca, P.

    2005-12-01

    A two-dimensional array of saddle coils at Mc poloidal and Nc toroidal positions is used on the EXTRAP T2R reversed-field pinch (Brunsell P R et al 2001 Plasma Phys. Control. Fusion 43 1457) to study active control of resistive wall modes (RWMs). Spontaneous growth of several RWMs with poloidal mode number m = 1 and different toroidal mode number n is observed experimentally, in agreement with linear MHD modelling. The measured plasma response to a controlled coil field and the plasma response computed using the linear circular cylinder MHD model are in quantitive agreement. Feedback control introduces a linear coupling of modes with toroidal mode numbers n, n' that fulfil the condition |n - n'| = Nc. Pairs of coupled unstable RWMs are present in feedback experiments with an array of Mc × Nc = 4 × 16 coils. Using intelligent shell feedback, the coupled modes are generally not controlled even though the field is suppressed at the active coils. A better suppression of coupled modes may be achieved in the case of rotating modes by using the mode control feedback scheme with individually set complex gains. In feedback with a larger array of Mc × Nc = 4 × 32 coils, the coupling effect largely disappears, and with this array, the main internal RWMs n = -11, -10, +5, +6 are all simultaneously suppressed throughout the discharge (7 8 wall times). With feedback there is a two-fold extension of the pulse length, compared to discharges without feedback.

  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. Behind the performance of flapping flyers

    CERN Document Server

    Ramananarivo, Sophie; Thiria, Benjamin

    2010-01-01

    Saving energy and enhancing performance are secular preoccupations shared by both nature and human beings. In animal locomotion, flapping flyers or swimmers rely on the flexibility of their wings or body to passively increase their efficiency using an appropriate cycle of storing and releasing elastic energy. Despite the convergence of many observations pointing out this feature, the underlying mechanisms explaining how the elastic nature of the wings is related to propulsive efficiency remain unclear. Here we use an experiment with a self-propelled simplified insect model allowing to show how wing compliance governs the performance of flapping flyers. Reducing the description of the flapping wing to a forced oscillator model, we pinpoint different nonlinear effects that can account for the observed behavior ---in particular a set of cubic nonlinearities coming from the clamped-free beam equation used to model the wing and a quadratic damping term representing the fluid drag associated to the fast flapping mo...

  4. 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...

  5. A dynamical system for interacting flapping swimmers

    Science.gov (United States)

    Oza, Anand; Ramananarivo, Sophie; Ristroph, Leif; Shelley, Michael

    2015-11-01

    We present the results of a theoretical investigation into the dynamics of interacting flapping swimmers. Our study is motivated by the recent experiments of Becker et al., who studied a one-dimensional array of self-propelled flapping wings that swim within each other's wakes in a water tank. They discovered that the system adopts certain ``schooling modes'' characterized by specific spatial phase relationships between swimmers. To rationalize these phenomena, we develop a discrete dynamical system in which the swimmers are modeled as heaving airfoils that shed point vortices during each flapping cycle. We then apply our model to recent experiments in the Applied Math Lab, in which two tandem flapping airfoils are free to choose both their speed and relative positions. We expect that our model may be used to understand how schooling behavior is influenced by hydrodynamics in more general contexts. Thanks to the NSF for its support.

  6. Active vibration control of nonlinear benchmark buildings

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xing-de; CHEN Dao-zheng

    2007-01-01

    The present nonlinear model reduction methods unfit the nonlinear benchmark buildings as their vibration equations belong to a non-affine system. Meanwhile,the controllers designed directly by the nonlinear control strategy have a high order, and they are difficult to be applied actually. Therefore, a new active vibration control way which fits the nonlinear buildings is proposed. The idea of the proposed way is based on the model identification and structural model linearization, and exerting the control force to the built model according to the force action principle. This proposed way has a better practicability as the built model can be reduced by the balance reduction method based on the empirical Grammian matrix. A three-story benchmark structure is presented and the simulation results illustrate that the proposed method is viable for the civil engineering structures.

  7. Actively controlled vibration welding system and method

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. 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.

  9. 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.

  10. Interpreting laser Doppler recordings from free flaps.

    Science.gov (United States)

    Svensson, H; Holmberg, J; Svedman, P

    1993-01-01

    Although the transfer of free flaps is nowadays accomplished with an increasing degree of safety, thrombosis of the microvascular anastomoses is still a problem. In order to avoid delay in re-operating, various methods for objective blood flow monitoring have been tried, among them Laser Doppler Flowmetry (LDF). When one reviews the literature, it is apparent that opinions differ about whether or not LDF is a reliable technique for this purpose. To focus on the need to interpret continuous recordings, this paper reports our findings in six latissimus dorsi free flaps chosen from our series of LDF monitoring procedures. One uneventful flap, no. 1, had an immediate postoperative LDF value of 4.5 perfusion units (PU). LDF values improved during the recovery period and the graphic recording showed fluctuations due to normal physiological variations of the blood flow in the flap. Another uneventful flap, no. 4, showed the same pattern, though at an appreciably lower level, 2 PU, on average. Flap no. 2 had an acceptably high value of 3.5 PU despite suffering a venous thrombosis. However, the LDF recording showed no fluctuations and the value declined gradually. Another flap, no. 3, showed fluctuations and blood flow was normal although the value decreased to 2.5 PU. In flap no. 5, any value between 2 and 3.5 PU could be obtained merely by adjusting the position of the probe in the holder. In no. 6, the LDF value suddenly dropped, accompanied by a decrease in the total amount of backscattered light, indicating venous obstruction which was confirmed at re-operation.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. BWR startup and shutdown activity transport control

    International Nuclear Information System (INIS)

    This paper summarizes BWR industry experience on good practices for controlling the transport of corrosion product activity during shutdowns, particularly refueling outages, and for startup chemistry control to minimize IGSCC (intergranular stress corrosion cracking). For shutdown, overall goals are to minimize adverse impacts of crud bursts and the time required to remove activated corrosion products from the reactor coolant during the shutdown process prior to refueling, and to assist plants in predicting and controlling radiation exposure during outages. For startup, the overall goals are to highlight conditions during early heatup and startup when sources of reactor coolant oxidants are high, when there is a greater likelihood for chemical excursions associated with refueling outage work activities, and when hydrogen injection is not available to mitigate IGSCC due to system design limitations. BWR water chemistry has changed significantly in recent years with the adoption of hydrogen water chemistry, zinc addition and noble metal chemical applications. These processes have, in some instances, resulted in significant activity increases during shutdown evolutions, which together with reduced time for cleanup because of shorter outages, has consequently increased outage radiation exposure. A review several recent outages shows that adverse effects from these conditions can be minimized, leading to the set of good practice recommendations for shutdown chemistry control. Most plants lose the majority of their hydrogen availability hours during early startup because feedwater hydrogen injection systems were not originally designed to inject hydrogen below 20% power. Hydrogen availability has improved through modifications to inject hydrogen at lower power levels, some near 5%. However, data indicate that IGSCC is accelerated during early startup, when dissolved oxygen and hydrogen peroxide levels are high and reactor coolant temperatures are in the 300 to 400 oF (

  12. TLR4信号转导通路活化在皮瓣缺血再灌注损伤中的作用%The role of toll like receptor-4 signal pathways activation in ischemia-reperfusion injury of island skin flap

    Institute of Scientific and Technical Information of China (English)

    简麒超; 吴小蔚; 宋海臣; 郑梁

    2012-01-01

    目的 探讨Toll样受体4(Toll-like receptors 4,TLR4)在皮瓣缺血再灌注(ischmeia-reperfusion,I/R)损伤中的意义.方法 将50只雄性SD大鼠进行编号,盲视下随机分为:假手术组(10只)、I/R组(20只)、TLR4抑制剂组(20只).制备右下腹岛状皮瓣I/R模型.TLR4抑制剂组处理组于再灌注前静脉注射E5564(5 mg/kg),分别于缺血再灌注后1、2、4和6h,采用免疫组化学法检测TLR4在皮瓣组织中的表达及分布,并行组织学观察.于术后7d,应用图像分析软件计算皮瓣存活比例.应用SPSS 18.0进行统计分析,两组间比较采用F检验.结果 免疫组织化学法显示I/R组比TLR4抑制组TLR4表达明显增强,且阳性部位主要是血管壁细胞及中性粒细胞.TLR4抑制剂组再灌注后TLR4活性受到抑制,中性粒细胞浸润及组织水肿程度较I/R组明显改善.术后7 d I/R组皮瓣存活比例为(51.70 ±7.62)%,TLR4抑制剂组皮瓣存活比例明显增高,达(80.31±11.63)%,与I/R组比较差异有统计学意义(P<0.01).结论 大鼠皮瓣缺血再灌注损伤后,皮瓣组织TLR4的表达上调中性粒细胞浸润增多.E5564能通过抑制TLR4活化,减少中性粒细胞浸润,减轻皮瓣I/R损伤.%Objective To determine the role of toll like receptor-4 signal pathways activation in ischemia-reperfusion injury of island skin flap.Methods A totol of 50 adult male SD rats were randomized into 3 groups: sham-operated group (n =10),ischemia/reperfusion group (n =20) and TLR4 inhibitor-eritoran tetrasodium (E5564)-treated group(n =20).The inguinal island skin flaps models were set up.A bolus of E5564 (5 mg/kg) was infused intravenously 60 min before reper fusionm.TLR4 binding activity in flap tissue was analyzed at 1,2,4 and 6 h of reperfusion by immunohistochemical technique and flaps were assessed histologically at 6 h of reperfusion.The viability of flaps was assessed 7 days postoperatively.Results Exprerssion TLR4 in skin flap tissue was significantly increased

  13. 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

  14. The dog-ear flap as an alternative for breast reconstruction in patients who have already undergone a DIEAP flap.

    Science.gov (United States)

    Colebunders, Britt; Depypere, Bernard; Van Landuyt, Koenraad

    2016-05-01

    Breast reconstruction in patients who have previously undergone deep inferior epigastric artery perforator flap (DIEAP) reconstruction or abdominoplasty is often challenging. Depending on patients' body habitus, several second-choice flaps have been described such as the transverse upper gracilis (TUG) flap, profundus femoris artery perforator (PFAP) flap, superior gluteal artery perforator (SGAP) flap, and lumbar artery perforator (LAP) flap. Patients who have undergone a DIEAP flap reconstruction or abdominoplasty occasionally present with dog ears on both sides of the abdominal scar. The adipose tissue and skin of these dog ears are supplied by perforators of the deep circumflex iliac artery (DCIA). The DCIA flap was first described in 1979 by Taylor. We introduce this abdominal "dog-ear" flap for autologous breast reconstruction. PMID:26951847

  15. Maxillofacial reconstruction with nasolabial and facial artery musculomucosal flaps.

    Science.gov (United States)

    Braasch, Daniel Cameron; Lam, Din; Oh, Esther S

    2014-08-01

    The nasolabial and facial artery musculomucosal (FAMM) flaps are predictable methods to reconstruct perioral and intraoral defects with vascularized tissue. The nasolabial flap can be harvested as an axial or random patterned flap, whereas the FAMM flap is truly an axial patterned flap, with either a superior or an inferior base. Both flaps have been widely used to provide predictable results, with low morbidity. Future studies are needed to further prove their use in compromised patients, including patients with a history of head and neck radiation and neck dissections. PMID:25086694

  16. Dorsal hand coverage with free serratus fascia flap

    DEFF Research Database (Denmark)

    Fotopoulos, Peter; Holmer, Per; Leicht, Pernille;

    2003-01-01

    serratus fascia flap, the connective tissue over the serratus muscle, for dorsal hand coverage. The flap consists of thin and well-vascularized pliable tissue, with gliding properties excellent for covering exposed tendons. It is based on the branches of the thoracodorsal artery, which are raised...... 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....

  17. Active Noise Control in Forest Machines

    OpenAIRE

    Forsgren, Fredrik

    2011-01-01

    Achieving a low noise level is of great interest to the forest machine industry. Traditionally this is obtained by using passive noise reduction, i.e. by using materials for sound isolation and sound absorption. Especially designs to attenuate low frequency noise tend to be bulky and impractical from an installation point of view. An alternative solution to the problem is to use active noise control (ANC). The basic principle of ANC is to generate an anti-noise signal designed to destructivel...

  18. Active noise control for high frequencies

    OpenAIRE

    Kaymak, E; Atherton, MA; Rotter, KRG; Millar, B.

    2006-01-01

    There are many applications that can benefit from Active Noise Control (ANC) such as in aircraft cabins and air conditioning ducts, i.e. in situations where technology interferes with human hearing in a harmful way or disrupts communication. Headsets with analogue ANC circuits have been used in the armed forces for attenuating frequencies below 1 kHz, which when combined with passive filtering offers protection across the whole frequency range of human hearing. A dental surgery is also a nois...

  19. 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.

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

    NARCIS (Netherlands)

    Werker, Paul M N

    2002-01-01

    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. Active Control of Shear Thickening in Suspensions

    CERN Document Server

    Lin, Neil Y C; Cates, Michael E; Sun, Jin; Cohen, Itai

    2016-01-01

    Shear thickening, an increase of viscosity with shear rate, is a ubiquitous phenomena in suspended materials that has implications for broad technological applications. Controlling this thickening behavior remains a major challenge and has led to empirical strategies ranging from altering the particle surfaces and shape to modifying the solvent properties. However, none of these methods allow for active control of flow properties during shear itself. Here, we demonstrate that by strategic imposition of a high-frequency and low-amplitude shear perturbation orthogonal to the primary shearing flow, we can largely eradicate shear thickening. The orthogonal shear effectively becomes a regulator for controlling thickening in the suspension, allowing the viscosity to be reduced by up to two decades on demand. In a separate setup, we show that such effects can be induced by simply agitating the sample transversely to the primary shear direction. Overall, the ability of in situ manipulation of shear thickening paves a...

  2. Blood flow dynamics and sensitivity in breasts after reconstruction with DIEP-flap.

    Science.gov (United States)

    Klasson, Stina; Svensson, Karin; Wollmer, Per; Velander, Patrik; Svensson, Henry

    2014-12-01

    A method of breast reconstruction is based on the Deep Inferior Epigastric Perforator (DIEP) technique. Skin and fat are transplanted from the abdomen to the chest; blood vessels are reconnected through microsurgery. Nerves are, however, left unconnected. This study aims to evaluate the blood flow and reinnervation of blood vessels and skin in breasts reconstructed by DIEP flaps without neural repair. In all, DIEP flaps of 10 patients were tested at an average of 16.3 months postoperatively. Blood flow was assessed by PeriScan PIM II System, both before and after indirect heating. Tactile perception threshold was assessed by Semmes-Weinstein monofilament and thermal sensibility by SENSELab MSA Thermotest. The patients' contralateral breasts were used as controls. The blood flow of the flaps was statistically significantly lower than in the control breasts, both before and after indirect heating. The change in blood flow after indirect heating did, however, not significantly differ when comparing the breasts. All flaps regained deep pressure sensibility in all four quadrants. Five patients regained even better sensibility in one of their quadrants. Seven patients regained perception of cold stimuli, five perceived warmth. This study has shown that skin blood flow regulation is present in DIEP flaps 1 year after reconstruction. Blood flow dynamics are very similar to those in the normal breast. There is also a recovery of tactile and thermal sensibility, but this study has not shown any clear parallels between recovery blood flow, tactile sensibility and thermal sensibility.

  3. Crystal structure of type I 3-dehydroquinate dehydratase of Aquifex aeolicus suggests closing of active site flap is not essential for enzyme action.

    Science.gov (United States)

    Devi, Aribam Swarmistha; Ebihara, Akio; Kuramitsu, Seiki; Yokoyama, Shigeyuki; Kumarevel, Thirumananseri; Ponnuraj, Karthe

    2013-03-01

    Structural analyses of enzymes involved in biosynthetic pathways that are present in micro-organisms, but absent from mammals (for example Shikimate pathway) are important in developing anti-microbial drugs. Crystal structure of the Shikimate pathway enzyme, type I 3-dehydroquinate dehydratase (3-DHQase) from the hyperthermophilic bacterium Aquifex aeolicus was solved both as an apo form and in complex with a ligand. The complex structure revealed an interesting structural difference when compared to other ligand-bound type I 3-DHQases suggesting that closure of the active site loop is not essential for catalysis. This provides new insights into the catalytic mechanism of type I 3-DHQases. PMID:23396056

  4. 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.

  5. Design and experimental results for a turbine with jet flap stator and jet flap

    Science.gov (United States)

    Bettner, J. L.; Blessing, J. O.

    1973-01-01

    The overall performance and detailed stator performance of a negative hub reaction turbine design featuring a moderately low solidity jet flap stator and a jet flap rotor were determined. Testing was conducted over a range of turbine expansion ratios at design speed. At each expansion ratio, the stator jet flow and rotor jet flow ranged up to about 7 and 8 percent, respectively, of the turbine inlet flow. The performance of the jet flap stator/jet flap rotor turbine was compared with that of a turbine which used the same jet flap rotor and a conventional, high solidity plan stator. The effect on performance of increased axial spacing between the jet stator and rotor was also investigated.

  6. A comparative molecular dynamics study on BACE1 and BACE2 flap flexibility.

    Science.gov (United States)

    Kumalo, H M; Soliman, Mahmoud E

    2016-10-01

    Beta-amyloid precursor protein cleavage enzyme1 (BACE1) and beta-amyloid precursor protein cleavage enzyme2 (BACE2), members of aspartyl protease family, are close homologs and have high similarity in their protein crystal structures. However, their enzymatic properties are different, which leads to different clinical outcomes. In this study, we performed sequence analysis and all-atom molecular dynamic (MD) simulations for both enzymes in their ligand-free states in order to compare their dynamical flap behaviors. This is to enhance our understanding of the relationship between sequence, structure and the dynamics of this protein family. Sequence analysis shows that in BACE1 and BACE2, most of the ligand-binding sites are conserved, indicative of their enzymatic property as aspartyl protease members. The other conserved residues are more or less unsystematically localized throughout the structure. Herein, we proposed and applied different combined parameters to define the asymmetric flap motion; the distance, d1, between the flap tip and the flexible region; the dihedral angle, φ, to account for the twisting motion and the TriCα angle, θ2 and θ1. All four combined parameters were found to appropriately define the observed "twisting" motion during the flaps different conformational states. Additional analysis of the parameters indicated that the flaps can exist in an ensemble of conformations, i.e. closed, semi-open and open conformations for both systems. However, the behavior of the flap tips during simulations is different between BACE1 and BACE2. The BACE1 active site cavity is more spacious as compared to that of BACE2. The analysis of 10S loop and 113S loop showed a similar trend to that of flaps, with the BACE1 loops being more flexible and less stable than those of BACE2. We believe that the results, methods and perspectives highlighted in this report would assist researchers in the discovery of BACE inhibitors as potential Alzheimer's disease therapies

  7. Role of the Use of Omental Flap in Prognosis of Cases with Induced Acute Pancreatitis in Experimental Dogs

    OpenAIRE

    Mohamed Hassan; Nader Shaaban; Abu-Seida, Ashraf M.; Mostafa Khodeir; Reem Jan; Hisham Elsharkawy; Engie Hefnawy

    2016-01-01

    Aim Acute pancreatitis frequently involves peripancreatic tissues and remote organ systems resulting in severe complications and high risk of mortality. Therefore, the present study was carried out to assess the effect of omental flap as a new treatment of acute pancreatitis. Methods Ten mongrel dogs with experimentally induced acute pancreatitis were randomly divided into two equal groups; treated and control groups. The pancreas was wrapped with omental flap in the treated group and the pan...

  8. Local flow control for active building facades

    Science.gov (United States)

    Kaligotla, Srikar; Chen, Wayne; Glauser, Mark

    2010-11-01

    Existing building facade designs are for a passive and an impermeable shell to prevent migration of outdoor air into the building and to control heat transfers between the exterior environment and the building interior. An active facade that can respond in real time to changing environmental conditions like wind speed and direction, pollutant load, temperature, humidity and light can lower energy use and maximize occupant comfort. With an increased awareness of cost and environmental effects of energy use, cross or natural ventilation has become an attractive method to lower energy use. Separated flow regions around such buildings are undesirable due to high concentration of pollutants, especially if the vents or dynamic windows for cross ventilation are situated in these regions. Outside pollutant load redistribution through vents can be regulated via flow separation control to minimize transport of pollutants into the building. Flow separation has been substantially reduced with the application of intelligent flow control tools developed at Syracuse University for flow around "silo" (turret) like structures. Similar flow control models can be introduced into buildings with cross ventilation for local external flow separation control. Initial experiments will be performed for turbulent flow over a rectangular block (scaled to be a mid-rise building) that has been configured with dynamic vents and unsteady suction actuators in a wind tunnel at various wind speeds.

  9. Extended thoracodorsal artery perforator flap for breast reconstruction.

    Science.gov (United States)

    Angrigiani, Claudio; Rancati, Alberto; Escudero, Ezequiel; Artero, Guillermo

    2015-12-01

    A total of 45 patients underwent partial or total autologous breast reconstruction after skin-sparing mastectomy, skin-reducing mastectomy, and quadrantectomy using a thoracodorsal artery perforator (TDAP) flap. The detailed surgical technique with its variations is explained in this report. The propeller, flip-over, conventional perforator, and muscle-sparing flaps have been described and evaluated. The flaps were partially or completely de-epithelialized. The conventional TDAP can be enlarged or "extended" as the traditional latissimus dorsi musculocutaneous (LD-MC) flap by incorporating the superior and inferior fat compartments. It can be referred to as the "extended TDAP flap". This technique augments the flap volume. In addition, this flap can serve as a scaffold for lipofilling to obtain autologous breast reconstruction in medium to large cases. There were two complete failures due to technical errors during flap elevation. Distal partial tissue suffering was observed in four flaps. These flaps were longer than usual; they reached the midline of the back. It is advisable to discard the distal medial quarter of the flap when it is designed up to the midline to avoid steatonecrosis or fibrosis. A retrospective analysis of the 39 flaps that survived completely revealed a satisfactory result in 82% of the cases. The main disadvantage of this procedure is the final scar. The TDAP flap is a reliable and safe method for partial or total breast autologous reconstruction. PMID:26645006

  10. Real Time Vibration Control of Active Suspension System with Active Force Control using Iterative Learning Algorithm

    OpenAIRE

    Kalaivani; Lakshmi; Rajeswari

    2013-01-01

    This paper presents concurrent vibration control of a laboratory scaled vibration isolator platform with Active Force Control (AFC) using Iterative Learning Algorithm (ILA). The work investigates the performance of the traditional Proportional Integral Derivative Controller (PIDC) with and without AFC using ILA for vibration suppression. The physical single degree of freedom quarter car has been interfaced with a personal computer using a National Instruments data acquisition card NI USB 6008...

  11. Active optics control development at the LBT

    Science.gov (United States)

    Ashby, David S.; Biddick, Christopher; Hill, John M.

    2014-07-01

    The Large Binocular Telescope (LBT) is built around two 8.4 m-diameter primary mirrors placed with a centerline separation of 14.4 m in a common altitude/azimuth mount. Each side of the telescope can utilize a deployable prime focus instrument; alternatively, the beam can be directed to a Gregorian instrument by utilizing a deployable secondary mirror. The direct-Gregorian beam can be intercepted and redirected to several bent-Gregorian instruments by utilizing a deployable tertiary mirror. Two of the available bent-Gregorian instruments are interferometers, capable of coherently combining the beams from the two sides of the telescope. Active optics can utilize as many as 26 linearly independent degrees of freedom to position the primary, secondary and tertiary mirrors to control optical collimation while the telescope operates in its numerous observing modes. Additionally, by applying differential forces at 160 locations on each primary mirror, active optics controls the primary mirror figure. The authors explore the challenges associated with collimation and primary mirror figure control at the LBT and outline the ongoing related development aimed at optimizing image quality and preparing the telescope for interferometric operations.

  12. Modified cup flap for volar oblique fingertip amputations

    Directory of Open Access Journals (Sweden)

    Ahmadli, A.

    2016-02-01

    Full Text Available We describe a modified volar “V-Y cup” flap for volar fingertip defects that do not exceed more than half of the distal phalanx for better aesthetic and functional outcome. In seven cases out of eight, the flap was elevated with a subdermal pedicle, whereas in one case, the flap was elevated as an island on the bilateral neurovascular bundle. The fingertips have been evaluated for sensibility using standard tests, hook nail deformity and patient satisfaction. Seven flaps have survived completely. The flap with skeletonized bilateral digital neurovascular bundle has shown signs of venous insufficiency on the 5 postoperative day with consecutive necrosis. Suturing the distal edges of the flap in a “cupping” fashion provided a normal pulp contour. The modified flap can be used for defects as mentioned above. Subdermally dissected pedicle-based flap is safe and easy to elevate. The aesthetic and functional outcomes have been reported to be satisfactory.

  13. 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.

  14. 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.

  15. Controller modification applied for active fault detection

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob; Poulsen, Niels Kjølstad

    2014-01-01

    This paper is focusing on active fault detection (AFD) for parametric faults in closed-loop systems. This auxiliary input applied for the fault detection will also disturb the external output and consequently reduce the performance of the controller. Therefore, only small auxiliary inputs are used...... 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....

  16. Actively-controlled Beds for Ambulances

    Institute of Scientific and Technical Information of China (English)

    Takahiko Ono; Hikaru Inooka

    2009-01-01

    During transportation by ambulance,a patient is exposed to inertial acceleration when an ambulance decelerates or turns a corner.Such acceleration often gives a patient physical stress such as blood pressure variation or body sway,which causes strong pain,feeling of discomfort or sometimes critical damage for seriously injured persons.To reduce this undesirable effect of the acceleration,the authors developed the actively-controlled bed (ACB) which controls the posture of a stretcher in real time to reduce foot-to-head and lateral acceleration acting on a supine person.This paper describes development of the ACB,including control system design and performance evaluation.The control system is designed by Zakian's framework,which comprises the principle of matching and the method of inequalities,so that the design specifications on the tracking error and the motor torque are satisfied.From the results of driving experiments and simulation,it is estimated that the ACB can reduce the acceleration acting on a patient by 65% in the foot-to-head direction and by 75% in the lateral direction.

  17. Active Displacement Control of Active Magnetic Bearing System

    Directory of Open Access Journals (Sweden)

    Kertész Milan

    2014-12-01

    Full Text Available The worldwide energy production nowadays is over 3400 GW while storage systems have a capacity of only 90 GW [1]. There is a good solution for additional storage capacity in flywheel energy storage systems (FES. The main advantage of FES is its relatively high efficiency especially with using the active magnetic bearing system. Therefore there exist good reasons for appropriate simulations and for creating a suitable magneto-structural control system. The magnetic bearing, including actuation, is simulated in the ANSYS parametric design language (APDL. APDL is used to create the loops of transient simulations where boundary conditions (BC are updated based upon a “gap sensor” which controls the nodal position values of the centroid of the shaft and the current density inputs onto the copper windings.

  18. Active noise control technology. Active soon seigyo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, M.; Kokubo, F.; Tanaka, S.; Yao, K. (Sharp Corp., Osaka (Japan))

    1994-05-10

    The signal processing method of the Active Noise Control (ANC) system was studied. The principle of ANC is to output secondary sound waves having opposite phase, identical amplitude from the control point of the sound wave of the primary sound source, and eliminate the noise by interference. As application fields, there are air conditioner ducts and compressors as one dimensional noise source, and automobile and axial fan as three dimensional noise source. In order to improve the stability of coefficient renewal algorithm of Adaptive Digital Filter (ADF), for generation of opposite phase noise, DC-LMS algorithm which can control the rise in gain of specified frequency zone was proposed. Furthermore, with the purpose of reducing the amount of operation, the introduction of lattice type AR filter was tested for the stability of the filter in IIR-ADF (Infinite Impulse Response Adaptive Digital Filter) and its application process. The applicability studies of these improved methods on the noise inside of ducts were actually measured, and the effect was verified. For the multi-channel control of 3 dimensional noise source, reference scanning method to reduce the filter operation was proposed. In the partial space noise eliminating experiment, it was made clear that it possesses equivalent effect to error scanning method. 11 refs., 14 figs., 1 tab.

  19. 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

  20. Deltopectoral Flap in the Era of Microsurgery

    Directory of Open Access Journals (Sweden)

    R. C. L. Chan

    2014-01-01

    Full Text Available Background. Our study aimed to review the role of deltopectoral (DP flap as a reconstructive option for defects in the head and neck region in the microvascular era. Methods. All patients who received DP flap reconstruction surgery at the Department of Surgery, Queen Mary Hospital, between 1999 and 2011 were recruited. Demographic data, indications for surgery, defect for reconstruction, and surgical outcomes were analyzed. Results. Fifty-four patients were included. All but two patients were operated for reconstruction after tumour resection. The remaining two patients were operated for necrotizing fasciitis and osteoradionecrosis. The majority of DP flaps were used to cover neck skin defect (63.0%. Other reconstructed defects included posterior pharyngeal wall (22.2%, facial skin defect (11.1%, and tracheal wall (3.7%. All donor sites were covered with partial thickness skin graft. Two patients developed partial flap necrosis at the tip and were managed conservatively. The overall flap survival rate was 96.3%. Conclusions. Albeit the technical advancements in microvascular surgery, DP still possesses multiple advantages (technical simplicity, reliable axial blood supply, large size, thinness, and pliability which allows it to remain as a useful, reliable, and versatile surgical option for head and neck reconstruction.

  1. 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.

  2. Lung tissue flap repairs esophagus defection with an inner chitosan tube stent

    Institute of Scientific and Technical Information of China (English)

    Gang Chen; Wen-Jun Shi

    2009-01-01

    AIM:To repair the partial esophagus defect with a chitosan stent, a new esophageal prosthesis made of pulmonary tissue with vascular pedicle. METHODS:Fifteen Japanese big ear white rabbits were divided into experimental group ( n = 10) and control group ( n = 5). Esophagus defect in rabbits of experimental group was repaired using lung tissue flap with a chitosan tube stent, gross and histological appearance was observed at week 2, 4 and 8 after operation, and barium sulphate X-ray screen was performed at week 10 after operation. Esophagus defect of rabbits in control group was repaired using lung tissue flap with no chitosan tube stent, gross and histological appearance was observed at week 2, 4 and 8 after operation, and barium sulphate X-ray screen was performed at week 10 after operation. RESULTS:In the experimental group, 6 rabbits survived for over two weeks, the lung tissue flap healed esophageal defec t ion, and squamous metaplasia occurred on the surface of lung tissue flap. At week 10 after operation, barium sulphate examination found that barium was fluent through the esophagus with no stricture or back stream, the creeping was good. In the control group, 4 rabbits survived for two weeks, the lung tissue flap healed esophageal defection with fibrous tissue hyperplasia, barium sulphate examination found that barium was fluent through the esophagus with a slight stricture or back stream, and the creeping was not good at week 10 after operation.CONCLUSION:Esophagus defect can be repaired using lung tissue flap with an inner chitosan tube stent.

  3. The aerodynamic and structural study of flapping wing vehicles

    OpenAIRE

    Zhou, Liangchen

    2013-01-01

    This thesis reports on the aerodynamic and structural study carried out on flapping wings and flapping vehicles. Theoretical and experimental investigation of aerodynamic forces acting on flapping wings in simple harmonic oscillations is undertaken in order to help conduct and optimize the aerodynamic and structural design of flapping wing vehicles. The research is focused on the large scale ornithopter design of similar size and configuration to a hang glider. By means of Theodorsen’s th...

  4. 14 CFR 25.1511 - Flap extended speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap extended speed. 25.1511 Section 25... Limitations § 25.1511 Flap extended speed. The established flap extended speed V FE must be established so that it does not exceed the design flap speed V F chosen under §§ 25.335(e) and 25.345, for...

  5. Pharyngo oesophageal strictures and its reconstruction by delto pectoral flaps

    OpenAIRE

    Guha, Goutam; S Gupta; Chakraborty, S

    2005-01-01

    Delto pectoral flap is a thin and pliable cutaneous axial flap suitable for the reconstruction of pharynx and upper oesophagus. Corrosive stricture of the pharyngo oesophageal area can very well be reconstructed by deltopectoral flap. Oesophageal reconstruction by viscera like stomach or colon often produces anastomic stricture at the upper anastomic site with hypopharynx or upper oesophagus. Delto pectoral flap can also be used to reconstruct this anastomotic stricture. Postoperative swallow...

  6. The Use of the Juri Temporo-Parieto-Occipital Flap

    OpenAIRE

    Juri, Jose; Valotta, Marìa Fernanda

    2005-01-01

    The temporo-parieto-occipital flap, introduced in 1969, was the first large monopedicled flap performed in the scalp for reconstructive and aesthetic purposes. Its versatility for correction of many areas of the scalp relies on its wide arch of rotation, based in the flap's pedicle, which is the superficial temporal artery and vein. The axial pattern of the flap is explained by the unique kind of vascularization present in the scalp, based on a profuse intraparietal blood flow with multiple a...

  7. The submental island flap for reconstruction of facial defects.

    OpenAIRE

    Prabhune K; Patni S; Gomes D.; Bhathena H; Kavarana N

    1998-01-01

    The procedure of facial resurfacing dictates that there should be an excellent colour and texture match between the facial and the transposed skin. Cervical flaps e.g. platysma flap are commonly used for reconstruction of facial defects but, with disadvantages like limited mobility, unacceptable donor site and unpredictable outcomes. The submental island flap is a new addition to the armamentorium of the Plastic Surgeon. It is an axial pattern flap based on the submental branch of facial arte...

  8. 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

  9. 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

    of control surfaces. The unsteady flow around such flaps is usually investigated by applying linearized unsteady aerodynamic models or by solving the two dimensional unsteady Reynolds averaged Navier-Stokes equations. The latter method is usually applied in combination with moving or interpolated body...... 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...... conforming meshes. A more flexible method would open up an opportunity to investigate the flow features of complex moving flap geometries in great detail. The immersed boundary method offers this flexibility, as the geometry is represented through the introduction of additional forcing terms in the governing...

  10. Real Time Vibration Control of Active Suspension System with Active Force Control using Iterative Learning Algorithm

    Directory of Open Access Journals (Sweden)

    Kalaivani

    2013-09-01

    Full Text Available This paper presents concurrent vibration control of a laboratory scaled vibration isolator platform with Active Force Control (AFC using Iterative Learning Algorithm (ILA. The work investigates the performance of the traditional Proportional Integral Derivative Controller (PIDC with and without AFC using ILA for vibration suppression. The physical single degree of freedom quarter car has been interfaced with a personal computer using a National Instruments data acquisition card NI USB 6008. The controllers are designed and simulated using LabVIEW simulation software. The results infer that the PIDC with AFC using ILA works superior than the PIDC.

  11. Mechanization and Control Concepts for Biologically Inspired Micro Aerial Vehicles

    Science.gov (United States)

    Raney, David L.; Slominski, Eric C.

    2003-01-01

    It is possible that MAV designs of the future will exploit flapping flight in order to perform missions that require extreme agility, such as rapid flight beneath a forest canopy or within the confines of a building. Many of nature's most agile flyers generate flapping motions through resonant excitation of an aeroelastically tailored structure: muscle tissue is used to excite a vibratory mode of their flexible wing structure that creates propulsion and lift. A number of MAV concepts have been proposed that would operate in a similar fashion. This paper describes an ongoing research activity in which mechanization and control concepts with application to resonant flapping MAVs are being explored. Structural approaches, mechanical design, sensing and wingbeat control concepts inspired by hummingbirds, bats and insects are examined. Experimental results from a testbed capable of generating vibratory wingbeat patterns that approximately match those exhibited by hummingbirds in hover, cruise, and reverse flight are presented.

  12. Prevention of Frey Syndrome With Temporal Fascia Flap in Parotidectomy.

    Science.gov (United States)

    Dai, Xiao-Ming; Liu, Hua; Li, Yi-Song; Ji, Sheng-Guo; Qin, Shao-Hua; Liu, Liu

    2015-12-01

    The objective of this study was to evaluate a total parotidectomy performed through a face-lift incision integrated with a temporal fascia flap. We have accomplished a group of 40 cases of total parotidectomy from July 2008 to May 2013. Twenty-two cases accepted a modified performance which combined rhytidectomy incision with temporal fascia flap. The other 18 cases were fulfilled by Blair incision and no reconstruction of parotid bed as control. The patients were followed up every 6 months. In the interviews, the assessment of the operation from patients was recorded. The cosmetic gratification, presence or absence of gustatory flushing or sweating, and functional reversion of facial nerve and great auricular nerve were surveyed by 3 investigators. The criteria that integrated the subjective with objective items were stipulated for evaluation. Gustatory sweating had been identified in 0% and 44% of patients of the testing and control group, respectively. The average scale of the experimental and control group postoperatively was 7.89 and 5.93 individually. The difference of the average scale between testing and control group presented statistical significance. The author's technique is either aesthetically satisfying or efficacious to prevention of gustatory sweating in total parotidectomy.

  13. 14 CFR 23.1511 - Flap extended speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap extended speed. 23.1511 Section 23.1511 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1511 Flap extended speed. (a) The flap extended speed V FE must be established so that it...

  14. Fibula free flap splitting for mandible reconstruction: A technical note

    OpenAIRE

    López-Arcas, José María; M. Burgueño; Del Castillo, J. L.

    2009-01-01

    Conformation of the fibula flap to passively adapt to the remaining mandible may be indeed challenging. A review of the ‘axial splitting’ technique for fibula free flaps is presented with a novel method of osteosynthesis. Adequate mandibular angle shape is achieved by performing this type of osteotomy with a minimal use of titanium hardware for flap insetting.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Numerical linearized MHD model of flapping oscillations

    Science.gov (United States)

    Korovinskiy, D. B.; Ivanov, I. B.; Semenov, V. S.; Erkaev, N. V.; Kiehas, S. A.

    2016-06-01

    Kink-like magnetotail flapping oscillations in a Harris-like current sheet with earthward growing normal magnetic field component Bz are studied by means of time-dependent 2D linearized MHD numerical simulations. The dispersion relation and two-dimensional eigenfunctions are obtained. The results are compared with analytical estimates of the double-gradient model, which are found to be reliable for configurations with small Bz up to values ˜ 0.05 of the lobe magnetic field. Coupled with previous results, present simulations confirm that the earthward/tailward growth direction of the Bz component acts as a switch between stable/unstable regimes of the flapping mode, while the mode dispersion curve is the same in both cases. It is confirmed that flapping oscillations may be triggered by a simple Gaussian initial perturbation of the Vz velocity.

  20. Scalp Free Flap Reconstruction Using Anterolateral Thigh Flap Pedicle for Interposition Artery and Vein Grafts

    OpenAIRE

    Chin Whan Kim; Sung Hee Hong; Jong Hoon Lee; Suk Chan Eun; Kyung Hee Min; Jun Hyung Park

    2012-01-01

    We experienced satisfactory outcomes by synchronously transplanting an artery and vein using an anterolateral thigh flap pedicle between the vascular pedicle and recipient vessel of a flap for scalp reconstruction. A 45-year-old man developed a subdural hemorrhage due to a fall injury. In this patient, the right temporal cranium was missing and the patient had 4×3 cm and 6×5 cm scalp defects. We planned a scalp reconstruction using a latissimus dorsi free flap. Intraoperatively, there was a s...

  1. Damping in flapping flight and its implications for manoeuvring, scaling and evolution.

    Science.gov (United States)

    Hedrick, Tyson L

    2011-12-15

    Flying animals exhibit remarkable degrees of both stability and manoeuvrability. Our understanding of these capabilities has recently been improved by the identification of a source of passive damping specific to flapping flight. Examining how this damping effect scales among different species and how it affects active manoeuvres as well as recovery from perturbations provides general insights into the flight of insects, birds and bats. These new damping models offer a means to predict manoeuvrability and stability for a wide variety of flying animals using prior reports of the morphology and flapping motions of these species. Furthermore, the presence of passive damping is likely to have facilitated the evolution of powered flight in animals by providing a stability benefit associated with flapping. PMID:22116750

  2. 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 .

  3. Biomimetic bluff body drag reduction by self-adaptive porous flaps

    CERN Document Server

    Mazellier, Nicolas; Kourta, Azeddine

    2011-01-01

    The performances of an original passive control system based on a biomimetic approach are assessed by investigating the flow over a bluff-body. This control device consists in a couple of flaps made from the combination of a rigid plastic skeleton coated with a porous fabric mimicking the shaft and the vane of the bird's feathers, respectively. The sides of a square cylinder have been fitted with this system so as to enable the flaps to freely rotate around their leading edge. This feature allows the movable flaps to self-adapt to the flow conditions. Comparing both the uncontrolled and the controlled flow, a significant drag reduction (up to 22%) has been obtained over a broad range of Reynolds number. The investigation of the mean flow reveals a noticeable modification of the flow topology at large scale in the vicinity of the controlled cylinder accounting for the increase of the pressure base in comparison with the natural flow. Meanwhile, the study of the relative motion of both flaps points out that the...

  4. Prediction control of active power filters

    Institute of Scientific and Technical Information of China (English)

    王莉娜; 罗安

    2003-01-01

    A prediction method to obtain harmonic reference for active power filter is presented. It is a new use ofthe adaptive predictive filter based on FIR. The delay inherent in digital controller is successfully compensated by u-sing the proposed method, and the computing load is not very large compared with the conventional method. Moreo-ver, no additional hardware is needed. Its DSP-based realization is also presented, which is characterized by time-va-riant rate sampling, quasi synchronous sampling, and synchronous operation among the line frequency, PWM gener-ating and sampling in A/D unit. Synchronous operation releases the limitation on PWM modulation ratio and guar-antees that the electrical noises resulting from the switching operation of IGBTs do not interfere with the sampledcurrent. The simulation and experimental results verify the satisfactory performance of the proposed method.

  5. Ribosome-dependent activation of stringent control.

    Science.gov (United States)

    Brown, Alan; Fernández, Israel S; Gordiyenko, Yuliya; Ramakrishnan, V

    2016-06-01

    In order to survive, bacteria continually sense, and respond to, environmental fluctuations. Stringent control represents a key bacterial stress response to nutrient starvation that leads to rapid and comprehensive reprogramming of metabolic and transcriptional patterns. In general, transcription of genes for growth and proliferation is downregulated, while those important for survival and virulence are upregulated. Amino acid starvation is sensed by depletion of the aminoacylated tRNA pools, and this results in accumulation of ribosomes stalled with non-aminoacylated (uncharged) tRNA in the ribosomal A site. RelA is recruited to stalled ribosomes and activated to synthesize a hyperphosphorylated guanosine analogue, (p)ppGpp, which acts as a pleiotropic secondary messenger. However, structural information about how RelA recognizes stalled ribosomes and discriminates against aminoacylated tRNAs is missing. Here we present the cryo-electron microscopy structure of RelA bound to the bacterial ribosome stalled with uncharged tRNA. The structure reveals that RelA utilizes a distinct binding site compared to the translational factors, with a multi-domain architecture that wraps around a highly distorted A-site tRNA. The TGS (ThrRS, GTPase and SpoT) domain of RelA binds the CCA tail to orient the free 3' hydroxyl group of the terminal adenosine towards a β-strand, such that an aminoacylated tRNA at this position would be sterically precluded. The structure supports a model in which association of RelA with the ribosome suppresses auto-inhibition to activate synthesis of (p)ppGpp and initiate the stringent response. Since stringent control is responsible for the survival of pathogenic bacteria under stress conditions, and contributes to chronic infections and antibiotic tolerance, RelA represents a good target for the development of novel antibacterial therapeutics. PMID:27279228

  6. [The gracilis muscle as musculocutaneous flap. Evaluation of 20 cases].

    Science.gov (United States)

    Gholam, D; Trevidic, P; Kleimann, P; Hautefeuille, P; Nicoletis, C

    1991-01-01

    The use of gracilis as muscular or myocutaneous flap is very well-known. The authors report 20 cases of gracilis flap including 13 reconstructions of the vaginal cavity following extended abdomino-perineal resection. Some technical points concerning the localization of the cutaneous part of the flap and the pedicle dissection are discussed. The use of gracilis flap is still limited in surgical teams following extended abdomino-perineal resection, nevertheless it is a very useful flap because of its low morbidity, the shortening of patient hospitalization and the very satisfying aesthetic result of the neo-vaginal cavity. PMID:1726389

  7. Actively controlled thin-shell space optics

    Science.gov (United States)

    Denoyer, Keith K.; Flint, Eric M.; Main, John A.; Lindler, Jason E.

    2003-08-01

    Increasingly, scientific and military missions require the use of space-based optical systems. For example, new capabilities are required for imaging terrestrial like planets, for surveillance, and for directed energy applications. Given the difficulties in producing and launching large optics, it is doubtful that refinements of conventional technology will meet future needs, particularly in a cost-effective manner. To meet this need, recent research has been investigating the feasibility of a new class of ultra-lightweight think-skin optical elements that combine recent advances in lightweight thermally formed materials, active materials, and novel sensing and control architectures. If successful, the approach may lead to an order of magnitude reduction in space optics areal density, improved large scale manufacturing capability, and dramatic reductions in manufacturing and launch costs. In a recent effort, a one meter thin-film mirror like structure was fabricated. This paper provides an overview of tools used to model and simulate this structure as well as results from structural dynamic testing. In addition, progress in the area of non-contact global shape control using smart materials is presented.

  8. Active controlled studies in antibiotic drug development.

    Science.gov (United States)

    Dane, Aaron

    2011-01-01

    The increasing concern of antibacterial resistance has been well documented, as has the relative lack of antibiotic development. This paradox is in part due to challenges with clinical development of antibiotics. Because of their rapid progression, untreated bacterial infections are associated with significant morbidity and mortality. As a consequence, placebo-controlled studies of new agents are unethical. Rather, pivotal development studies are mostly conducted using non-inferiority designs versus an active comparator. Further, infections because of comparator-resistant isolates must usually be excluded from the trial programme. Unfortunately, the placebo-controlled data classically used in support of non-inferiority designs are largely unavailable for antibiotics. The only available data are from the 1930s and 1940s and their use is associated with significant concerns regarding constancy and assay sensitivity. Extended public debate on this challenge has led to proposed solutions by some in which these concerns are addressed by using very conservative approaches to trial design, endpoints and non-inferiority margins, in some cases leading to potentially impractical studies. To compound this challenge, different Regulatory Authorities seem to be taking different approaches to these key issues. If harmonisation does not occur, antibiotic development will become increasingly challenging, with the risk of further decreases in the amount of antibiotic drug development. However with clarity on Regulatory requirements and an ability to feasibly conduct global development programmes, it should be possible to bring much needed additional antibiotics to patients.

  9. High performance composites with active stiffness control.

    Science.gov (United States)

    Tridech, Charnwit; Maples, Henry A; Robinson, Paul; Bismarck, Alexander

    2013-09-25

    High performance carbon fiber reinforced composites with controllable stiffness could revolutionize the use of composite materials in structural applications. Here we describe a structural material, which has a stiffness that can be actively controlled on demand. Such a material could have applications in morphing wings or deployable structures. A carbon fiber reinforced-epoxy composite is described that can undergo an 88% reduction in flexural stiffness at elevated temperatures and fully recover when cooled, with no discernible damage or loss in properties. Once the stiffness has been reduced, the required deformations can be achieved at much lower actuation forces. For this proof-of-concept study a thin polyacrylamide (PAAm) layer was electrocoated onto carbon fibers that were then embedded into an epoxy matrix via resin infusion. Heating the PAAm coating above its glass transition temperature caused it to soften and allowed the fibers to slide within the matrix. To produce the stiffness change the carbon fibers were used as resistance heating elements by passing a current through them. When the PAAm coating had softened, the ability of the interphase to transfer load to the fibers was significantly reduced, greatly lowering the flexural stiffness of the composite. By changing the moisture content in PAAm fiber coating, the temperature at which the PAAm softens and the composites undergo a reduction in stiffness can be tuned. PMID:23978266

  10. The study of expanded tri-lobed flap in a rabbit model: possible flap model in ear reconstruction?

    Directory of Open Access Journals (Sweden)

    Yüreklý Yakup

    2003-12-01

    Full Text Available Abstract Background Local flaps are widely used in reconstructive surgery. Tri-lobed skin flap is a relatively new flap and there has been no experimental model of this flap. This flap can be used for repair of full thickness defects in the face, ears and alar region. Based on the size of ears in a rabbit, we designed a model of ear reconstruction using expanded tri-lobed flap. Local flaps are more advantageous in that they provide excellent color and texture matching up with those of the face, adequately restore ear contour, place scars in a favorable location and ideally accomplish these goals in a single stage with minimal donor site morbidity. Methods Eight adult New Zealand rabbits were divided into two groups. 50 ml round tissue expander were implanted to four rabbits. After completion of the expansion, a superiorly based tri-lobed flap was elevated and a new ear was created from the superior dorsal skin of each rabbit. Scintigraphy with Technetium-99m pertecnetate was performed to evaluate flap viability. Results Subtotal flap necrosis was seen in all animals in non-expanded group. New ear in dimensions of the original ear was created in expanded group without complication. Perfusion and viability of the flaps were proved by Technetium-99m pertecnetate scintigraphy. Conclusion According to our knowledge this study is the first to demonstrate animal model in tri-lobed flap. Also, our technique is the first application of the trilobed flap to the possible ear reconstruction. We speculated that this flap may be used mastoid based without hair, in human. Also, tri-lobed flap may be an alternative in reconstruction of cylindrical organs such as penis or finger.

  11. Propeller thoracodorsal artery perforator flap for breast reconstruction

    Science.gov (United States)

    Angrigiani, Claudio; Escudero, Ezequiel; Artero, Guillermo; Gercovich, Gustavo; Deza, Ernesto Gil

    2014-01-01

    Background The thoracodorsal artery perforator (TDAP) flap has been described for breast reconstruction. This flap requires intramuscular dissection of the pedicle. A modification of the conventional TDAP surgical technique for breast reconstruction is described, utilizing instead a propeller TDAP flap. The authors present their clinical experience with the propeller TDAP flap in breast reconstruction alone or in combination with expanders or permanent implants. Methods From January 2009 to February 2013, sixteen patients had breast reconstruction utilizing a propeller TDAP flap. Retrospective analysis of patient characteristics, clinical indications, procedure and outcomes were performed. The follow-up period ranged from 4 to 48 months. Results Sixteen patients had breast reconstruction using a TDAP flap with or without simultaneous insertion of an expander or implant. All flaps survived, while two cases required minimal resection due to distal flap necrosis, healing by second intention. There were not donor-site seromas, while minimal wound dehiscence was detected in two cases. Conclusions The propeller TDAP flap appears to be safe and effective for breast reconstruction, resulting in minimal donor site morbidity. The use of this propeller flap emerges as a true alternative to the traditional TDAP flap. PMID:25207210

  12. Active control of aerodynamic noise; Active control ni yoru furyoku soon no seigyo

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, M. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1996-10-01

    This paper introduces summary and examples of active noise control (ANC) and active flow control (AFC) as the aerodynamic noise control techniques. The ANC is a technique to generate noise of a reverse phase which cancels the original noise. Noise reduced especially effectively by the ANC is noise from fans and ducts used for engine air supply and exhaust. The ANC is effective in low frequencies, and when used with a passive method, a compact exhaust silencer can be realized, which has high noise reducing performance over the whole frequency band and has low pressure loss. Signal processing in active noise reduction system is always so adjusted that noise is discharged from a secondary noise source in which signals detected by a detection microphone is given a digital filter treatment, and output from an error microphone is minimized. The AFC has been incapable of realizing a reverse phase over a wide frequency band when depended on analog treatment. However, the authors have developed an adaptive type feedback control system, and verified that the system can be applied to any frequency variation and control it in a stable manner. 15 refs., 9 figs., 1 tab.

  13. Topology optimization of pressure adaptive honeycomb for a morphing flap

    Science.gov (United States)

    Vos, Roelof; Scheepstra, Jan; Barrett, Ron

    2011-03-01

    The paper begins with a brief historical overview of pressure adaptive materials and structures. By examining avian anatomy, it is seen that pressure-adaptive structures have been used successfully in the Natural world to hold structural positions for extended periods of time and yet allow for dynamic shape changes from one flight state to the next. More modern pneumatic actuators, including FAA certified autopilot servoactuators are frequently used by aircraft around the world. Pneumatic artificial muscles (PAM) show good promise as aircraft actuators, but follow the traditional model of load concentration and distribution commonly found in aircraft. A new system is proposed which leaves distributed loads distributed and manipulates structures through a distributed actuator. By using Pressure Adaptive Honeycomb (PAH), it is shown that large structural deformations in excess of 50% strains can be achieved while maintaining full structural integrity and enabling secondary flight control mechanisms like flaps. The successful implementation of pressure-adaptive honeycomb in the trailing edge of a wing section sparked the motivation for subsequent research into the optimal topology of the pressure adaptive honeycomb within the trailing edge of a morphing flap. As an input for the optimization two known shapes are required: a desired shape in cruise configuration and a desired shape in landing configuration. In addition, the boundary conditions and load cases (including aerodynamic loads and internal pressure loads) should be specified for each condition. Finally, a set of six design variables is specified relating to the honeycomb and upper skin topology of the morphing flap. A finite-element model of the pressure-adaptive honeycomb structure is developed specifically tailored to generate fast but reliable results for a given combination of external loading, input variables, and boundary conditions. Based on two bench tests it is shown that this model correlates well

  14. STUDY ON FLAP SIDE-EDGE NOISE BASED ON THE FLY-OVER MEASUREMENTS WITH A PLANAR MICROPHONE ARRAY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A large planar microphone array, which consists of 111 microphones, was successfully applied to measure a two-dimensional mapping of the sound sources on landing aircraft. The focus was on the flap side-edge noise source in this paper. The spectra, directivity and sound pressure level of flap side-edge noise of 10 aircraft were presented in this paper. It is found that the spectrum of flap side-edge noise is a broadband noise with some tones in some cases. Two different types of tone sources are found. It is proposed that one type of these tone sources is trailing edge semi-baffled dipole source, and another is produced from the shedding of vortex from the wing cusp. The total sound pressure level of flap side-edge broadband noise has no obvious directionality. However, the directivity of the tone noise in the flap side-edge noise spectrum is obvious. It is demonstrated that the local flow field is the key to controlling the flap side-edge noise.

  15. 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.

  16. Reconstruction after Anterior Chest Wall Keloid Resection Using Internal Mammary Artery Perforator Propeller Flaps

    Science.gov (United States)

    Ogawa, Rei; Ono, Shimpei; Akaishi, Satoshi; Dohi, Teruyuki; Iimura, Takeshi; Nakao, Junichi

    2016-01-01

    Background: It is difficult to completely resect huge anterior chest wall keloids and then close the wound directly. We report here our retrospective analysis of our case series of patients with such keloids who underwent reconstruction with internal mammary artery perforator (IMAP) pedicled propeller flaps and then received postoperative high-dose-rate superficial brachytherapy. Methods: All consecutive patients with large/severe keloids on the anterior chest wall who underwent keloid resection followed by reconstruction with IMAP-pedicled propeller flaps and then high-dose-rate superficial brachytherapy in our academic hospital were identified. All cases were followed for >18 months. Donor site position, perforator pedicle, flap size, angle of flap rotation, complications, and recurrence were documented. Results: There were nine men and one woman. The average age was 37.9 years. The average follow-up duration was 28.7 months. The largest flap was 16 × 4 cm. The dominant perforators of the internal mammary artery were located in the sixth (n = 2), seventh (n = 5), eighth (n = 1), and ninth (n = 2) intercostal spaces. Twelve months after surgery, patients reported marked relief from keloid-associated pain and itching, except in two patients who underwent partial keloid resection; their remaining keloids were still troublesome but after conservative therapies, including steroid ointments/plasters, the keloids gradually ameliorated. Eighteen months after surgery, there was no keloid recurrence or new development of keloids on the donor site. Conclusions: IMAP-pedicled propeller flaps transfer skin tension from the anterior chest wall to the abdomen. Our series suggests that this approach combined with radiation therapy can control keloid recurrence.

  17. Results of instrumental and operative implementation of T-Flap

    Science.gov (United States)

    Marcelli, M.; Madonia, A.; Piermattei, V.; Mainardi, U.

    2012-04-01

    The development of new technologies for the study of the ocean processes is one of the most innovative aspects of oceanographic research that increasingly requires a large amount of data for an integrated approach to in situ observations, forecasting models and remotely sensed data. At now the marine measurement technologies are too expensive for an extensive utilization. The T-Flap technology (Temperature-Fluorescence LAunchable Probe) meets these needs by providing low cost and user-friendly in situ measuring of physical and bio-optical variables of water bodies, as opposed to traditional methods. Many experimental laboratory tests were carried out in order to increase the instrumental sensitivity of the fluorimetric sensor for the detection of chlorophyll a concentration. To test the selected components (LEDs, diodes, filters) and their new configurations, an optical circuit has been realized consisting on three prototypes of the measuring cell. Fluorescence excitation and detection efficiency of the new electro-optical assemblages were also tested by the comparison between the voltage output signals and spectroscopic in vivo fluorescence measures both of natural seawater samples and marine cultures at different concentrations. The upgraded sensors were tested during different oceanographic surveys performed in the last years both in the Tyrrhenian Sea and Adriatic Sea. The technological achievements were applied in different operative conditions: profiler along the water column (not expendable) and stand alone (in continuous surface acquisitions along tracks, in continuous acquisition on a buoy). In this work we present the results of the latest research activities on T-Flap evolution. In addition preliminary results about new sensors currently under development are shown, such as CDOM (Cromophoric Dissolved Organic Matter) fluorimetric sensor, based on T-Flap fluorescence technology, and conductivity sensor.

  18. 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.

  19. Design and performance prediction of swashplateless helicopter rotors with trailing edge flaps and tabs

    Science.gov (United States)

    Falls, Jaye

    This work studies the design of trailing edge controls for swashplateless helicopter primary control, and examines the impact of those controls on the performance of the rotor. The objective is to develop a comprehensive aeroelastic analysis for swashplateless rotors in steady level flight. The two key issues to be solved for this swashplateless control concept are actuation of the trailing edge controls and evaluating the performance of the swashplateless rotor compared to conventionally controlled helicopters. Solving the first requires simultaneous minimization of trailing flap control angles and hinge moments to reduce actuation power. The second issue requires not only the accurate assessment of swashplateless rotor power, but also similar or improved performance compared to conventional rotors. The analysis consists of two major parts, the structural model and the aerodynamic model. The inertial contributions of the trailing edge flap and tab are derived and added to the system equations in the structural model. Two different aerodynamic models are used in the analysis, a quasi-steady thin airfoil theory that includes arbitrary hinge positions for the flap and the tab, and an unsteady lifting line model with airfoil table lookup based on wind tunnel test data and computational fluid dynamics simulation. The design aspect of the problem is investigated through parametric studies of the trailing edge flap and tab for a Kaman-type conceptual rotor and a UH-60A swashplateless variant. The UH-60A model is not changed except for the addition of a trailing edge flap to the rotor blade, and the reduction of pitch link stiffness to imitate a soft root spring. Study of the uncoupled blade response identifies torsional stiffness and flap hinge stiffness as important design features of the swashplateless rotor. Important trailing edge flap and tab design features including index angle, aerodynamic overhang, chord and length are identified through examination of coupled

  20. 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.

  1. Neural Anatomy of the Anterolateral Thigh Flap.

    Science.gov (United States)

    Luenam, Suriya; Prugsawan, Krit; Kosiyatrakul, Arkaphat; Chotanaphuti, Thanainit; Sriya, Piyanee

    2015-06-01

    The anterolateral thigh (ALT) flap is one of the commonly used sensate flaps for intra-oral, hand, and foot reconstruction. The objective of this study was to describe the anatomic location of the sensory nerves supplying the ALT flap in relation to the surface landmarks and with the vascular pedicles. The dissections were carried out in 28 embalmed specimens. An axial line from the anterior superior iliac spine to the superolateral border of the patella and two circles with radii of 5 and 10 cm centered on the midpoint of the former line were used for the surface landmarks. At the intersection point of the axial line and the 10-cm circle, the main lateral femoral cutaneous nerve (LFCN) and its anterior branch were located within 1 and 2.4 cm, respectively. At the intersection point of the axial line and the 5-cm circle, the anterior branch of the LFCN was located within 2.8 cm. The anterior branch of the LFCN can be detected within 3 cm from the central perforator pedicle in all specimens. The posterior branch of the LFCN, superior perforator nerve, and median perforator nerve were found in more variable locations. The findings from our study provide additional information for clinical use in the planning of sensate ALT flap harvest. PMID:26078503

  2. Development of a generic activities model of command and control

    OpenAIRE

    Stanton, NA; Baber, C; Walker, GH; Houghton, RJ; McMaster, R.; Stewart, R; Harris, D.; 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...

  3. Binding of single walled carbon nanotube to WT and mutant HIV-1 proteases: analysis of flap dynamics and binding mechanism.

    Science.gov (United States)

    Meher, Biswa Ranjan; Wang, Yixuan

    2012-09-01

    Most of the currently treated HIV-1 protease (HIV-PR) inhibitors have been prone to suffer from the mutations associated drug resistance. Therefore, it is necessary to search for potent alternatives against the drug resistance. In the current study we have tested the single-walled carbon nanotube (SWCNT) as an inhibitor in wild type (WT) as well as in three primary mutants (I50V(PR), V82A(PR) and I84V(PR)) of the HIV-1-PR through docking the SWCNT in the active site region, and then performed all-atom MD simulations for the complexes. The conformational dynamics of HIV-PR with a 20 ns trajectory reveals that the SWCNT can effectively bind to the HIV-1-PR active site and regulate the flap dynamics such as maintaining the flap-flap closed. To gain an insight into the binding affinity, we also performed the MM-PBSA based binding free energy calculations for the four HIV-PR/SWCNT complexes. It was observed that, although the binding between the SWCNT and the HIV-PR decreases due to the mutations, the SWCNTs bind to the HIV-PRs 3-5 folds stronger than the most potent HIV-1-PR inhibitor, TMC114. Remarkably, the significant interactions with binding energy higher than 1kcal/mol focus on the flap and active regions, which favors closing flap-flap and deactivating the active residues of the HIV-PR. The flap dynamics and binding strength information for HIV-PR and SWCNTs can help design SWCNT-based HIV-1-PR inhibitors. PMID:23142620

  4. Assessing safety of negative-pressure wound therapy over pedicled muscle flaps: A retrospective review of gastrocnemius muscle flap.

    Science.gov (United States)

    Lance, Samuel; Harrison, Lindsey; Orbay, Hakan; Boudreault, David; Pereira, Gavin; Sahar, David

    2016-04-01

    The use of negative-pressure wound therapy (NPWT) for management of open wounds and immobilization of split-thickness skin grafts (STSGs) over wounds has been well described. However, there is a concern for potential compromise of flap viability when NPWT is used for skin grafts over pedicled muscle flaps. We have used NPWT to immobilize STSGs in eight patients who underwent a pedicled gastrocnemius muscle flap operation in our department. We applied a negative pressure of -75 mmHg on the muscle flaps for 5 days postoperatively. All wounds healed successfully, with a 97.5 ± 5.5% mean STSG uptake. No flap necrosis was observed. In our series, the use of NPWT for fixation of STSGs over pedicled gastrocnemius muscle flap was effective and had no negative impact on flap viability. PMID:26732293

  5. Automotive active noise control (ANC) system. Jidoshayo active noise control (ANC) system

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, S. (Nissan Motor Co. Ltd., Tokyo (Japan))

    1992-11-25

    This paper introduces a successful development of an active noise control (ANC) system that selects and controls noise in an automobile compartment. This is a system that Nissan has developed for practical use for the first time in the world by using an adaptive control theory and a digital signal processor (DSP) that uses ultra-high speed operating elements. The principle for noise silencing in the ANC system utilizes interference of cyclic amplitude of sound with opposite phase. Sounds in an automobile include informative sounds, agreeable sounds, and noise, and combinations of these sounds work complexly on people in a car, of which extent varies depending on individuals. The adaptive control minimizes sounds picked up by a microphone into controlled speaker sound via an multiple error filtered algorithm (MEF-[sub X]LMS) and an adaptive digital filter. Major components of the system include a microphone, a speaker, and a control unit (comprising the adaptive algorithm and the adaptive filter), all having been developed newly. A DSP that operates on ultra-high speed operating elements was used for speedy compliance with complex algorithms, so that the controlled sound combined of engine noise with compartment sound field can be calculated. The noise was reduced by more than 10 dB at maximum. 7 figs.

  6. Transplantation of hypoxia preconditioned bone marrow mesenchymal stem cells improves survival of ultra-long random skin flap

    Institute of Scientific and Technical Information of China (English)

    WANG Ji-chang; XIA Lin; SONG Xiao-bin; WANG Chun-e; WEI Feng-cai

    2011-01-01

    Background Random flap is one kind of the most widely used skin flaps in reconstructive surgery; however, partial necrosis of its distal end remains a significant problem now. The aim of this study was to evaluate the effect of hypoxia preconditioned bone marrow mesenchymal stem cells (HpBMSCs) transplantation on ultra-long random skin flap survival in rats.Methods Normoxic bone marrow mesenchymal stem cells (nBMSCs) were cultured under normoxia (20% O2) and HpBMSCs under hypoxia (1% O2) for 48 hours before transplantation. Thirty Sprague-Dawley rats were randomly divided into control group, nBMSCs group and HpBMSCs group with each consisting of 10 rats. Survival area of ultra-long random skin flap on the dorsal of rats was measured seven days after flap surgery and cell transplantation. Cell survival in vivo, microvessel density and vascular endothelial growth factor (VEGF) were evaluated by histological examination and enzyme-linked immunosorbent assay.Results Compared with other two groups, flap survival area in HpBMSCs group was significantly larger (P <0.05).Microvessel density in HpBMSCs group (36.20+8.19) was higher than that in nBMSCs group (30.01±5.68) and control group (17.60±4.19) (P <0.05). VEGF in HpBMSCs group ((300.05±50.41) pg/g) was higher than those in nBMSCs group ((240.55±33.64) pg/g) and control group ((191.65±32.58) pg/g) (P <0.05).Conclusion HpBMSCs transplantation improves ultra-long random skin flap survival via promoting angiogenesis of more survival cells.

  7. Using adjoint-based optimization to study wing flexibility in flapping flight

    Science.gov (United States)

    Wei, Mingjun; Xu, Min; Dong, Haibo

    2014-11-01

    In the study of flapping-wing flight of birds and insects, it is important to understand the impact of wing flexibility/deformation on aerodynamic performance. However, the large control space from the complexity of wing deformation and kinematics makes usual parametric study very difficult or sometimes impossible. Since the adjoint-based approach for sensitivity study and optimization strategy is a process with its cost independent of the number of input parameters, it becomes an attractive approach in our study. Traditionally, adjoint equation and sensitivity are derived in a fluid domain with fixed solid boundaries. Moving boundary is only allowed when its motion is not part of control effort. Otherwise, the derivation becomes either problematic or too complex to be feasible. Using non-cylindrical calculus to deal with boundary deformation solves this problem in a very simple and still mathematically rigorous manner. Thus, it allows to apply adjoint-based optimization in the study of flapping wing flexibility. We applied the ``improved'' adjoint-based method to study the flexibility of both two-dimensional and three-dimensional flapping wings, where the flapping trajectory and deformation are described by either model functions or real data from the flight of dragonflies. Supported by AFOSR.

  8. Robot-Assisted Free Flap in Head and Neck Reconstruction

    Directory of Open Access Journals (Sweden)

    Han Gyeol Song

    2013-07-01

    Full Text Available Background  Robots have allowed head and neck surgeons to extirpate oropharyngealtumors safely without the need for lip-split incision or mandibulotomy. Using robots inoropharyngealreconstruction is newbut essentialfor oropharyngeal defectsthatresultfromrobotic tumor excision. We report our experience with robotic free-flap reconstruction ofhead and neck defectsto exemplify the necessity forrobotic reconstruction.Methods  We investigated head and neck cancer patients who underwent ablation surgeryand free-flap reconstruction by robot. Between July 1, 2011 andMarch 31, 2012, 5 caseswereperformed and patient demographics, location of tumor, pathologic stage, reconstructionmethods, flap size, recipient vessel, necessary pedicle length, and operation time wereinvestigated.Results  Among five free-flap reconstructions, four were radial forearm free flaps and onewas an anterolateral thigh free-flap. Four flaps used the superior thyroid artery and oneflap used a facial artery as the recipient vessel. The average pedicle length was 8.8 cm. Flapinsetting and microanastomosis were achieved using a specially manufactured roboticinstrument. The total operation timewas 1,041.0 minutes(range, 814 to 1,132 minutes, andcomplicationsincluding flap necrosis, hematoma, andwound dehiscence did not occur.Conclusions  Thisstudy demonstratesthe clinically applicable use ofrobotsin oropharyngealreconstruction, especially using a free flap. A robot can assist the operator in insettingthe flap at a deep portion of the oropharynx without the need to perform a traditionalmandibulotomy. Robot-assisted reconstruction may substitute for existing surgical methodsand is accepted asthemost up-to-datemethod.

  9. Pedicle versus free flap reconstruction in patients receiving intraoperative brachytherapy.

    Science.gov (United States)

    Geiger, Erik J; Basques, Bryce A; Chang, Christopher C; Son, Yung; Sasaki, Clarence T; McGregor, Andrew; Ariyan, Stephan; Narayan, Deepak

    2016-08-01

    Introduction This study compared complication rates between pedicle flaps and free flaps used for resurfacing of intraoperative brachytherapy (IOBT) implants placed following head and neck tumour extirpation to help clarify the ideal reconstructive procedure for this scenario. Patients and methods A retrospective review of reconstructions with IOBT at our institution was conducted. Patient and treatment details were recorded, as were the number and type of flap complications, including re-operations. Logistic regressions compared complications between flap groups. Results Fifty free flaps and 55 pedicle flaps were included. On multivariate analysis, free flap reconstruction with IOBT was significantly associated with both an increased risk of having any flap complication (OR = 2.9, p = 0.037) and with need for operative revision (OR = 3.5, p = 0.048) compared to pedicle flap reconstruction. Conclusions In the setting of IOBT, free flaps are associated with an increased risk of having complications and requiring operative revisions. PMID:26983038

  10. Effect of flapping trajectories on the dragonfly aerodynamics

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of translational, figure-eight and double-figure-eight flapping trajectories on the dragonfly aerodynamics were numerically studied by solving the Navier-Stokes equations. There is a common characteristic regarding the lift/drag force coefficients that the downstroke flapping provides the lift forces while the upstroke flapping creates the thrust forces for different flapping trajectories. The maximum lift force coefficient exceeds five for the translational trajectory. It is greater than six for the figure-eight and double-figure-eight flapping trajectories, which is sufficiently larger than unity under the steady state flight condition. The ellipse and double-figure-eight flapping trajectories yield the decrease of the lift force, while the figure-eight flapping trajectory yields higher lift force as well as the thrust force than the translational flapping one. During the insect flight, the wing flapping status should be changed instantaneously to satisfy various requirements. Study of the flapping trajectories on the insect aerodynamics is helpful for the design of the Micro-air-vehicles (MAVs).

  11. STUDY OF VARIOUS MODIFICATIONS OF REVERSE SURAL ARTERY FLAP

    Directory of Open Access Journals (Sweden)

    Jainath

    2013-10-01

    Full Text Available A BS T R ACT : Soft tissue reconstruction of distal third leg, heel and ankle reg ion is a challenging problem because of poor vascularity and limited mobility of skin. The reverse sural artery with ideal flap thickness, minimal donor site morbidity, lack of functional muscle loss, short recovery time, wide arc of rotation and safe vasc ularity makes it a preferable flap for covering such defects. AIMS A N D OBJECTIVES : To study various modifications of distally based reverse sural artery flap to suit the defects and for better survival of flaps. RESULTS : It is a retrospective study conduct ed in our institute to cover the distal leg and foot defects.60 cases of distal leg defects exposing vital structure who underwent reverse sural artery flap coverage were included in the study .5 of the 60 flaps had complete flap necrosis and another11 fla ps had partial necrosis.73.4% of the flaps survived during the follow up period of 1 years with good functional outcome. CONCLUSIONS : Reverse sural artery flap with its modifications is a good flap for the defects of distal leg, heel and ankle defects

  12. Optimal designs for dose finding studies with an active control

    OpenAIRE

    Benda, Norbert; Bretz, Frank; Dette, Holger; Kiss , Christine

    2011-01-01

    Dose finding studies often compare several doses of a new compound with a marketed standard treatment as an active control. In the past, however, research has focused mostly on experimental designs for placebo-controlled dose finding studies. To the best of our knowledge, optimal designs for dose finding studies with an active control have not been considered so far. As the statistical analysis for an active controlled dose finding study can be formulated in terms of a mixture ...

  13. Low Activity Waste Feed Process Control Strategy

    International Nuclear Information System (INIS)

    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

  14. 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.

  15. Active control of smart structures : an overall approach

    OpenAIRE

    Nestorović Tamara; Trajkov Miroslav

    2010-01-01

    The paper presents active control of smart structures within a focused frame of piezoelectric applications in active vibration and noise attenuation with potentials for the use in mechanical and civil engineering. An overall approach to active control of piezoelectric structures involves subsequent steps of modeling, control, simulation, experimental verification and implementation. Each of these steps is regarded in details. Different application examples showing the feasibility of the activ...

  16. 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...

  17. 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.

  18. 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...... 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...

  19. 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

  20. Magnetic Levitation Technique for Active Vibration Control

    OpenAIRE

    Hoque, Emdadul; Mizuno, Takeshi

    2010-01-01

    A zero-power controlled magnetic levitation system has been presented in this chapter. The unique characteristic of the zero-power control system is that it can generate negative stiffness with zero control current in the steady-state which is realized in this chapter. The detail characteristics of the levitation system are investigated. Moreover, two major contributions, the stiffness adjustment and nonlinear compensation of the suspension system have been introduced elaborately. Often, ther...

  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. Incidence of flap procedures in the management of burn patients.

    Science.gov (United States)

    Lineaweaver, William C; Craft-Coffman, Beretta; Oswald, Tanya M

    2015-03-01

    Increased survival of burn patients presents opportunities for reconstructive strategies to improve outcomes in management of acute and secondary burn injuries. To assess one such strategy, namely flap reconstruction, we reviewed cases performed during the first 4.5 years of the JMS Burn and Reconstruction Center. We found that flap procedures accounted for 0.8% of acute cases (23 of 2723 procedures) and 33% of secondary cases (260 of 790 procedures). This initial finding shows that in this practice flap procedures are applied to a small number of acute problems while flap procedures comprise 33% of secondary procedures. Reconstructive flap surgery plays a measurable role in burn treatment at this center. Further study of outcomes and timing could lead to better understanding of optimal strategies for flap reconstruction in burns.

  3. Aerodynamic characteristics of a large-scale hybrid upper surface blown flap model having four engines

    Science.gov (United States)

    Carros, R. J.; Boissevain, A. G.; Aoyagi, K.

    1975-01-01

    Data are presented from an investigation of the aerodynamic characteristics of large-scale wind tunnel aircraft model that utilized a hybrid-upper surface blown flap to augment lift. The hybrid concept of this investigation used a portion of the turbofan exhaust air for blowing over the trailing edge flap to provide boundary layer control. The model, tested in the Ames 40- by 80-foot Wind Tunnel, had a 27.5 deg swept wing of aspect ratio 8 and 4 turbofan engines mounted on the upper surface of the wing. The lift of the model was augmented by turbofan exhaust impingement on the wind upper-surface and flap system. Results were obtained for three flap deflections, for some variation of engine nozzle configuration and for jet thrust coefficients from 0 to 3.0. Six-component longitudinal and lateral data are presented with four engine operation and with the critical engine out. In addition, a limited number of cross-plots of the data are presented. All of the tests were made with a downwash rake installed instead of a horizontal tail. Some of these downwash data are also presented.

  4. Application of microvascular free osteocutaneous flaps in the management of post-radiation recurrent oral cancer

    International Nuclear Information System (INIS)

    Fifty-nine patients underwent free flap osteocutaneous reconstruction that consisted of flaps of the dorsum of the foot in 26 patients and iliac crest flaps in 33 with a success rate of 92 percent and a mortality rate of 1.6 percent. These flaps, which require the expertise of microvascular surgeons, are time-consuming and complicate operating room and time management, but they represent a remarkable advance in reconstruction that can facilitate cosmetic and functional recovery of the patient. In particular, they promote healing in radiation-recurrent oral cancer and represent a definitive form of management for established radionecrosis of the mandible. The large volume of tissue available with iliac crest osteocutaneous grafts permits the management of patients with extensive cancer involving the skin, mucosa, and bone, but cancer control may still be disappointing and there is a need for improved adjuvant chemotherapy protocols. This technique appears to be a dependable, repeatable, and significant advance in management of the patient with head and neck cancer

  5. Two-Dimensional Aerodynamic Models of Insect Flight for Robotic Flapping Wing Mechanisms of Maximum Efficiency

    Institute of Scientific and Technical Information of China (English)

    Thien-Tong Nguyen; Doyoung Byun

    2008-01-01

    In the "modified quasi-steady" approach, two-dimensional (2D) aerodynamic models of flapping wing motions are analyzed with focus on different types of wing rotation and different positions of rotation axis to explain the force peak at the end of each half stroke. In this model, an additional velocity of the mid chord position due to rotation is superimposed on the translational relative velocity of air with respect to the wing. This modification produces augmented forces around the end of eachstroke. For each case of the flapping wing motions with various combination of controlled translational and rotational velocities of the wing along inclined stroke planes with thin figure-of-eight trajectory, discussions focus on lift-drag evolution during one stroke cycle and efficiency of types of wing rotation. This "modified quasi-steady" approach provides a systematic analysis of various parameters and their effects on efficiency of flapping wing mechanism. Flapping mechanism with delayed rotation around quarter-chord axis is an efficient one and can be made simple by a passive rotation mechanism so that it can be useful for robotic application.

  6. Pumping by flapping in a viscoelastic fluid

    CERN Document Server

    Pak, On Shun

    2010-01-01

    In a world without inertia, Purcell's scallop theorem states that in a Newtonian fluid a time-reversible motion cannot produce any net force or net flow. Here we consider the extent to which the nonlinear rheological behavior of viscoelastic fluids can be exploited to break the constraints of the scallop theorem in the context of fluid pumping. By building on previous work focusing on force generation, we consider a simple, biologically-inspired geometrical example of a flapper in a polymeric (Oldroyd-B) fluid, and calculate asymptotically the time-average net fluid flow produced by the reciprocal flapping motion. The net flow occurs at fourth order in the flapping amplitude, and suggests the possibility of transporting polymeric fluids using reciprocal motion in simple geometries even in the absence of inertia. The induced flow field and pumping performance are characterized and optimized analytically. Our results may be useful in the design of micro-pumps handling complex fluids.

  7. CATERPILLAR ADVANCEMENT FOR PARTIALLY NECROSED DELTOPECTORAL FLAP

    Directory of Open Access Journals (Sweden)

    Anand Narayan

    2015-04-01

    Full Text Available Development of electric lamp by Thomas Elva Edison had significant impact on human civilization. With increasing production of electrical energy to meet ongoing demands of increased frequency of electrical injuries. Despite increased awareness of potential dangers, elect ricity is responsible for many fatalities all over the world. Electrical burn accounts for ~3% of all burn related injuries. Estimated 3, 000 annual admittions to burn units. Electrical burn have bimodal distribution ~1/3 children <6 yrs ( E lectric cords & wall outlets ~2/3 miners, construction, & electrical workers. Our case is one that of a 12 year old male child having electrical injury over face and neck with exposed angle of mandible which was covered by Deltopectoral flap with caterpillar advancement of flap.

  8. Dynamics of Flapping Flag in Axial Flow

    Science.gov (United States)

    Abderrahmane, Hamid Ait; Fayed, Mohamed; Gunter, Amy-Lee; Paidoussis, Michael P.; Ng, Hoi Dick

    2010-11-01

    We investigate experimentally the phenomenon of the flapping of a flag, placed within a low turbulent axial flow inside a small scale wind tunnel test section. Flags of different sizes and flexural rigidities were used. Image processing technique was used and the time series of a given point on the edge of the flag was analyzed. The stability condition of the flag was obtained and compared to the recent theoretical models and numerical simulations. Afterwards, the nonlinear dynamics of the flapping was investigated using nonlinear time series method. The nonlinear dynamics is depicted in phase space and the correlation dimension of the attractors is determined. On the basis of observations made in this study, some conclusions on the existing models were drawn.

  9. Active control design of modular tensegrity structures

    OpenAIRE

    Amouri, Sarah; Averseng, Julien; Dubé, Jean-François

    2013-01-01

    In this paper, a general methodology for the design of modular active tensegrity structures is presented. The objectives are to propose systems such as grids or footbridges that would be able to actively damper their first vibration modes and to adapt their geometry using a small number of activators. This approach is validated experimentally on a plane regular tensegrity grid. Using numerical simulation, an application on the model of a modular tensegrity footbridge is presented.

  10. Flight test pilot evaluation of a delayed flap approach procedure

    Science.gov (United States)

    Bull, J. S.; Edwards, F. G.; Foster, J. D.; Hegarty, D. M.; Drinkwater, F. J., III

    1977-01-01

    Using NASA's CV-990 aircraft, a delayed flap approach procedure was demonstrated to nine guest pilots from the air transport industry. Four demonstration flights and 37 approaches were conducted under VFR weather conditions. A limited pilot evaluation of the delayed flap procedure was obtained from pilot comments and from questionaires they completed. Pilot acceptability, pilot workload, and ATC compatibility were quantitatively rated. The delayed flap procedure was shown to be feasible, and suggestions for further development work were obtained.

  11. Medial circumflex femoral artery flap for ischial pressure sore

    OpenAIRE

    Palanivelu S

    2009-01-01

    A new axial pattern flap based on the terminal branches of the medial circumflex femoral artery is described for coverage of ischial pressure sore. Based on the terminal branches of the transverse branch of medial circumflex femoral artery, which exit through the gap between the quadratus femoris muscle above and the upper border of adductor magnus muscle below, this fascio cutaneous flap is much smaller than the posterior thigh flap but extremely useful to cover ischeal pressure sores. The s...

  12. Fenestration of bone flap during decompressive craniotomy for subdural hematoma

    OpenAIRE

    Ha Son Nguyen; Ninh Doan; Christopher Wolfla; Glen Pollock

    2016-01-01

    Background: Persistent/recurrent extra-axial hemorrhage may occur after decompression of a subdural hematoma (SDH) followed by an immediate replacement of bone flap. A fenestration of the bone flap may encourage extra-axial fluid absorption; however, the literature has not explored this technique. Methods: Forty-four consecutive patients who underwent surgical decompression of SDH with immediate replacement of bone flap were divided into two groups: Fenestration (F), n = 33, and no fenest...

  13. Design of Insect-Scale Flapping Wing Vehicles

    OpenAIRE

    Ahmed Nabawy, Mostafa Ramadan

    2015-01-01

    This thesis contributes to the state of the art in integrated design of insect-scale piezoelectric actuated flapping wing vehicles through the development of novel theoretical models for flapping wing aerodynamics and piezoelectric actuator dynamics, and integration of these models into a closed form design process.A comprehensive literature review of available engineered designs of miniature rotary and flapping wing vehicles is provided. A novel taxonomy based on wing and actuator kinematics...

  14. USB noise reduction by nozzle and flap modifications

    Science.gov (United States)

    Hayden, R. E.

    1976-01-01

    The development of concepts for reducing upper surface blown flap noise at the source through flap modifications and special nozzles is reviewed. In particular, recent results obtained on the aerodynamic and acoustic performance of flaps with porous surfaces near the trailing edge and multi-slotted nozzles are reviewed. Considerable reduction (6-10 db) of the characteristic low frequency peak is shown. The aerodynamic performance is compared with conventional systems, and prospects for future improvements are discussed.

  15. [Pedicled versus free TRAM flap for breast reconstruction].

    Science.gov (United States)

    Galla, T J; Lukas, B; Feller, A M

    1999-03-01

    In breast reconstruction, the free TRAM-flap offers many advantages over the pedicled TRAM-flap. Due to its superior perfusion, the free flap rarely develops necrosis. Shaping of the flap is easier due to the lack of the thick muscle pedicle. Because the rectus muscle is spared, there is minimal donor site morbidity. However, the necessary microvascular anastomoses reduced the acceptance of the free TRAM-flap. During a 13-months period, 51 breast reconstructions were performed in 41 patients, 31 unilateral and ten bilateral. 45 flaps served for delayed reconstruction and six flaps for immediate reconstruction. The operations were performed by two teams working simultaneously. The average operating time was 3.9 hours for unilateral and 6.9 hours for bilateral delayed reconstruction. For immediate reconstruction, 6.2 and 6.3 hours were required for uni- and bilateral procedures, respectively. In 38 flaps, the thoracodorsal vessels served as recipient vessels; 13 flaps were anastomosed to the internal mammary artery and vein. Postoperative complications were observed in 13 patients. Three vessel anastomoses had to be revised. In one flap, a partial necrosis occurred; in two flaps hematoma evacuation was necessary. Two patients suffered from fat necroses at the abdomen and one umbilicus was lost. Skin irritations and seromas at the abdomen occurred in five patients. Pulmonary embolism was diagnosed in one patient three weeks postoperatively. Abdominal hernias or bulging in the epigastric area were not observed up to 15 months after reconstruction. These results reveal a low complication rate for breast reconstruction with the free TRAM-flap. The advantages of this technique as compared to the pedicled technique are discussed.

  16. 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.

  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. Propeller Perforator Flaps in Distal Lower Leg:Evolution and Clinical Applications

    OpenAIRE

    Georgescu, Alexandru V.

    2012-01-01

    Simple or complex defects in the lower leg, and especially in its distal third, continue to be a challenging task for reconstructive surgeons. A variety of flaps were used in the attempt to achieve excellence in form and function. After a long evolution of the reconstructive methods, including random pattern flaps, axial pattern flaps, musculocutaneous flaps and fasciocutaneous flaps, the reappraisal of the works of Manchot and Salmon by Taylor and Palmer opened the era of perforator flaps. T...

  19. Phase and gain control policies for robust active vibration control of flexible structures

    OpenAIRE

    Zhang, Kai; Scorletti, Gérard; Ichchou, Mohamed; Mieyeville, F.

    2013-01-01

    The interest of this paper is to develop a general and systematic robust control methodology for active vibration control of flexible structures. For this purpose, first phase and gain control policies are proposed to impose qualitative frequency-dependent requirements on the controller to consider a complete set of control objectives. Then the proposed control methodology is developed by employing phase and gain control policies in the dynamic output feedback H∞ control: according to the set...

  20. Nonlinear Predictive Control of Semi-Active Landing Gear System

    OpenAIRE

    Wu, Dongsu; Gu, Hongbin; Liu, Hui

    2010-01-01

    The application of model predictive control and constructive nonlinear control methodology to semi-active landing gear system is studied in this paper. A unified shock absorber mathematical model incorporates solenoid valve’s electromechanical and magnetic dynamics is built to facilitate simulation and controller design. Then we propose a hierarchical control structure to deal with the high nonlinearity. A dual mode model predictive controller as an outer loop controller is developed to gen...

  1. Design, Fabrication and Testing Of Flapping Wing Micro Air Vehicle

    Directory of Open Access Journals (Sweden)

    K. P. Preethi Manohari Sai

    2016-01-01

    Full Text Available Flapping flight has the potential to revolutionize micro air vehicles (MAVs due to increased aerodynamic performance, improved maneuverability and hover capabilities. The purpose of this project is to design and fabrication of flapping wing micro air vehicle. The designed MAV will have a wing span of 40cm. The drive mechanism will be a gear mechanism to drive the flapping wing MAV, along with one actuator. Initially, a preliminary design of flapping wing MAV is drawn and necessary calculation for the lift calculation has been done. Later a CAD model is drawn in CATIA V5 software. Finally we tested by Flying.

  2. 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.

  3. Thoracodorsal artery perforator flap for upper limb reconstruction

    International Nuclear Information System (INIS)

    Thoracodorsal artery perforator flap (TAP) is a feasible option to reconstruct defects in upper limb where only skin and subcutaneous tissue is required. Methods: This case series was carried out at department of Plastic and Reconstructive Surgery Combined Military Hospital Rawalpindi. A total of 5 patients with upper limb defects were reconstructed with thoracodorsal artery musculocutaneous perforator flaps. Among them, 3 were pedicled and two free TAP flaps. All flaps except one pedicled flap were raised on a single perforator pedicle. Recipient sites were one axilla, two shoulder regions and two hands. The soft tissue defects in the patients had resulted from burns, trauma, wide local excision of synovial sarcoma and surgery for hidradenitis suppurativa. Preoperative hand held Doppler ultrasound was used to locate and mark the perforator. Results: All flaps survived without significant complications. All flaps were hyperemic in the immediate postoperative period. We designed and raised all the five flaps on eccentrically placed perforators. All the raised perforators originated from the descending branch of the thoracodorsal artery. The donor sites were closed primarily with linear scars in all cases except one, in which partial closure was accomplished with split thickness skin grafting (STSG). Conclusion: The thoracodorsal artery perforator flap has great potential for reconstructing large, relatively shallow, defects of upper limb because of its suitable skin quality, texture and appropriate thickness, as well as hidden donor site, a reliable pedicle and sparing of muscle unit. (author)

  4. Medial circumflex femoral artery flap for ischial pressure sore

    Directory of Open Access Journals (Sweden)

    Palanivelu S

    2009-01-01

    Full Text Available A new axial pattern flap based on the terminal branches of the medial circumflex femoral artery is described for coverage of ischial pressure sore. Based on the terminal branches of the transverse branch of medial circumflex femoral artery, which exit through the gap between the quadratus femoris muscle above and the upper border of adductor magnus muscle below, this fascio cutaneous flap is much smaller than the posterior thigh flap but extremely useful to cover ischeal pressure sores. The skin redundancy below the gluteal fold allows a primary closure of the donor defect. It can also be used in combination with biceps femoris muscle flap.

  5. Oropharyngeal reconstruction with a pedicled submandibular gland flap.

    Science.gov (United States)

    Mashrah, Mubarak A; Zhou, Shang-Hui; Abdelrehem, Ahmed; Ma, Chunyue; Xu, Liqun; He, Yue; Zhang, Chen-Ping

    2016-05-01

    Locoregional flaps are widely used for reconstruction of small and medium defects in the oral cavity. The submandibular gland flap is a pedicled flap, which derives its blood supply from the facial artery, based on the submandibular gland. We describe the use of the flap in 20 patients who required oropharyngeal reconstruction with a pedicled submandibular gland flap after resection of a tumour between July 2012 and October 2014. Patients with squamous cell carcinoma were excluded. All flaps were pedicled on the facial vessels (inferiorly in 17 patients and superiorly in 3). The indications were: reconstruction of intraoral mucosal defects (n=13), filling the parapharyngeal dead space (n=6), and obliteration of the mastoid (n=1). All the flaps atrophied, but with no clinical effect. One patient developed partial loss of the flap, and one early leakage. There were no cases of xerostomia, and no signs of recurrence during the postoperative follow-up period of 3-26 months. The flap is useful, as it is simple and reliable for reconstruction of small to medium oropharyngeal defects in carefully selected cases, and gives good cosmetic and functional results. PMID:26388070

  6. 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.

  7. Active vibration and noise control by hybrid active acoustic panels

    Energy Technology Data Exchange (ETDEWEB)

    Stoebener, U.; Gaul, L. [Stuttgart Univ. (Germany). Inst. A fuer Mechanik

    2001-07-01

    In the present paper a hybrid passive and active treatment for vibration and noise reduction of plate type structures is proposed. The treatment is manufactured as sandwich structure and is called hybrid active acoustic panel. The passive component is used to reduce the vibration and sound radiation for high frequencies whereas the active part of the system is designed for the low frequency range. By selecting the thickness of the passive damping layer a certain frequency limit is defined, which divides the high and low frequency range. The actuator and sensor layout of the active component is evaluated by using the mode shapes of the low frequency range. According to the evaluated layout a hybrid active acoustic panel is manufactured and experimentally tested. The experimental results validate the proposed concept. (orig.)

  8. 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...

  9. Brain-Activity-Driven Real-Time Music Emotive Control

    OpenAIRE

    Giraldo, Sergio; Ramirez, Rafael

    2013-01-01

    Active music listening has emerged as a study field that aims to enable listeners to interactively control music. Most of active music listening systems aim to control music aspects such as playback, equalization, browsing, and retrieval, but few of them aim to control expressive aspects of music to convey emotions. In this study our aim is to enrich the music listening experience by allowing listeners to control expressive parameters in music performances using their perceived emotional stat...

  10. Self-Tuning Active Vibration Control of Flexible Beam Structures

    OpenAIRE

    M.O. Tokhi; Hossain, M A

    1994-01-01

    This paper presents the design and performance evaluation of an adaptive active control mechanism for vibration suppression in flexible beam structures. A cantilever beam system in transverse vibration is considered. First order control finite difference methods are used to study the behaviour of the beam and develop a suitable test and verification platform. An active vibration control algorithm is developed within an adaptive control framework for broadband cancellation of vibration along t...

  11. Active and Passive Flow Control around Simplified Ground Vehicles

    Directory of Open Access Journals (Sweden)

    C.H Bruneau

    2012-01-01

    Full Text Available The aim of this work is to control the flow around ground vehicles by active or/and passive strategies. The active control is achieved by steady, pulsed or closed-loop jets located at the backof the simplified car model. The passive control is performed using porous layers between the solid body and the fluid in order to modify the shear forces. The two previous control methods can be coupled to improve the drag reduction.

  12. Comparative study of visual acuity and aberrations after intralase femtosecond LASIK: small corneal flap versus big corneal flap

    Institute of Scientific and Technical Information of China (English)

    Ya-Li; Zhang; Lei; Liu; Chang-Xia; Cui; Ming; Hu; Zhao-Na; Li; Li-Jun; Cao; Xiu-Hua; Jing; Guo-Ying; Mu

    2014-01-01

    AIM:To study the effects of different flap sizes on visual acuity, refractive outcomes, and aberrations after femtosecond laser for laser keratomileusis (LASIK). ·METHODS: In each of the forty patients enrolled, 1 eye was randomly assigned to receive treatment with a 8.1mm diameter corneal flap, defined as the small flap, while the other eye was treated with a 8.6mm diameter corneal flap, defined as the big flap. Refractive errors, visual acuity, and higher -order aberrations were compared between the two groups at week 1, month 1 and 3 postoperatively. · RESULTS: The postoperative refractive errors and visual acuity all conformed to the intended goal. Postoperative higher -order aberrations were increased, especially in spherical aberration (Z12) and vertical coma (Z7). There were no statistically significant differences between the two groups in terms of postoperative refractive errors, visual acuity, root mean square of total HOAs (HO -RMS), trefoil 30° (Z6), vertical coma (Z7), horizontal coma (Z8), trefoil 0° (Z9), and spherical aberration (Z12) at any point during the postoperative follow-up. ·CONCLUSION: Both the small and big flaps are safe and effective procedures to correct myopia, provided the exposure stroma meets the excimer laser ablations. The personalized size corneal flap is feasible, as we can design the size of corneal flap based on the principle that the corneal flap diameter should be equal to or greater than the sum of the maximum ablation diameter and apparatus error.

  13. A propeller flap for single-stage nose reconstruction in selected patients: supratrochlear artery axial propeller flap.

    Science.gov (United States)

    Cordova, Adriana; D'Arpa, Salvatore; Massimiliano, Tripoli; Toia, Francesca; Moschella, Francesco

    2014-06-01

    The paramedian forehead flap is the gold standard technique for nose reconstruction. It requires two different surgical operations which prolonged the postoperative dressing and care. We present our 5-year experience with a propeller flap based on the supratrochlear artery, which allows one-stage transfer of the forehead skin to the nose without the need for pedicle division. This technique is indicated in a selected group of patients who are not suitable for multiple-stage reconstructions because they have concurrent medical conditions, reduced mobility, or live far away from specialized medical centers. We have renamed this procedure as supratrochlear artery axial propeller flap, from the acronym STAAP flap, to stress the axial, well known and constant, vascularization of the flap. In the past 5 years, we have been performing 25 STAAP flaps; full-thickness nasal reconstruction was performed in 11 cases. The patients were 16 males and 9 females, with a mean age of 79.5 years. All patients had multiple comorbidities. Complete flap survival was observed in 23 cases and healing was complete in 7 days. In two cases, there was a partial distal necrosis of the flap treated conservatively. Cosmetic results were good and the patient's satisfaction was significant. These results indicate that the STAAP flap is a reliable and useful technique in selected cases, as old or noncompliant patients who benefit from a one-stage technique of nose reconstruction. PMID:24918712

  14. Navier-Stokes Computations of a Wing-Flap Model With Blowing Normal to the Flap Surface

    Science.gov (United States)

    Boyd, D. Douglas, Jr.

    2005-01-01

    A computational study of a generic wing with a half span flap shows the mean flow effects of several blown flap configurations. The effort compares and contrasts the thin-layer, Reynolds averaged, Navier-Stokes solutions of a baseline wing-flap configuration with configurations that have blowing normal to the flap surface through small slits near the flap side edge. Vorticity contours reveal a dual vortex structure at the flap side edge for all cases. The dual vortex merges into a single vortex at approximately the mid-flap chord location. Upper surface blowing reduces the strength of the merged vortex and moves the vortex away from the upper edge. Lower surface blowing thickens the lower shear layer and weakens the merged vortex, but not as much as upper surface blowing. Side surface blowing forces the lower surface vortex farther outboard of the flap edge by effectively increasing the aerodynamic span of the flap. It is seen that there is no global aerodynamic penalty or benefit from the particular blowing configurations examined.

  15. The use of propeller perforator flaps for diabetic limb salvage: a retrospective review of 25 cases

    Directory of Open Access Journals (Sweden)

    Alexandru V. Georgescu

    2012-10-01

    Full Text Available Background : Peripheral vascular disease and/or diabetic neuropathy represent one of the main etiologies for the development of lower leg and/or diabetic foot ulcerations, and especially after acute trauma or chronic mechanical stress. The reconstruction of such wounds is challenging due to the paucity of soft tissue resources in this region. Various procedures including orthobiologics, skin grafting (SG with or without negative pressure wound therapy and local random flaps have been used with varying degrees of success to cover diabetic lower leg or foot ulcerations. Other methods include: local or regional muscle and fasciocutaneous flaps, free muscle and fasciocutaneous, or perforator flaps, which also have varying degrees of success. Patients and methods : This article reviews 25 propeller perforator flaps (PPF which were performed in 24 diabetic patients with acute and chronic wounds involving the foot and/or lower leg. These patients were admitted beween 2008 and 2011. Fifteen PPF were based on perforators from the peroneal artery, nine from the posterior tibial artery, and one from the anterior tibial artery. Results : A primary healing rate (96% was obtained in 18 (72% cases. Revisional surgery and SG for skin necrosis was performed in six (24% cases with one complete loss of the flap (4% which led to a lower extremity amputation. Conclusions : The purpose of this article is to review the use of PPF as an effective method for soft tissue coverage of the diabetic lower extremity and/or foot. In well-controlled diabetic patients that present with at least one permeable artery in the affected lower leg, the use of PPF may provide an alternative option for soft tissue reconstruction of acute and chronic diabetic wounds.

  16. The use of propeller perforator flaps for diabetic limb salvage: a retrospective review of 25 cases

    Science.gov (United States)

    Georgescu, Alexandru V.; Matei, Ileana R.; Capota, Irina M.

    2012-01-01

    Background Peripheral vascular disease and/or diabetic neuropathy represent one of the main etiologies for the development of lower leg and/or diabetic foot ulcerations, and especially after acute trauma or chronic mechanical stress. The reconstruction of such wounds is challenging due to the paucity of soft tissue resources in this region. Various procedures including orthobiologics, skin grafting (SG) with or without negative pressure wound therapy and local random flaps have been used with varying degrees of success to cover diabetic lower leg or foot ulcerations. Other methods include: local or regional muscle and fasciocutaneous flaps, free muscle and fasciocutaneous, or perforator flaps, which also have varying degrees of success. Patients and methods This article reviews 25 propeller perforator flaps (PPF) which were performed in 24 diabetic patients with acute and chronic wounds involving the foot and/or lower leg. These patients were admitted beween 2008 and 2011. Fifteen PPF were based on perforators from the peroneal artery, nine from the posterior tibial artery, and one from the anterior tibial artery. Results A primary healing rate (96%) was obtained in 18 (72%) cases. Revisional surgery and SG for skin necrosis was performed in six (24%) cases with one complete loss of the flap (4%) which led to a lower extremity amputation. Conclusions The purpose of this article is to review the use of PPF as an effective method for soft tissue coverage of the diabetic lower extremity and/or foot. In well-controlled diabetic patients that present with at least one permeable artery in the affected lower leg, the use of PPF may provide an alternative option for soft tissue reconstruction of acute and chronic diabetic wounds. PMID:23050066

  17. 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.

  18. Active control of radiated sound using nearfield pressure sensing

    Institute of Scientific and Technical Information of China (English)

    CHEN Ke'an; YIN Xuefei

    2004-01-01

    Based on nearfield sound pressure sensing to pick up error information, an approach for constructing active acoustic structure to effectively reduce radiated sound power at low frequency is proposed. The idea is that a nearfield pressure after active control is used as error signals and transformed into an objective function in adaptive active control process.Firstly sound power expression using near-field pressure radiated from a flexible structure is derived, and then three kind of nearfield pressure based active control strategies, I.e. Minimization of radiated sound power, minimization of sound power for dominant radiation modes and minimization of sound power for modified dominant radiation modes are respectively presented and applied to active control of radiated single and broadband noise. Finally computer simulations on sound power reduction under three strategies are conducted and it is shown that the proposed active control strategies are invalid and considerable reduction in radiated sound power can be achieved.

  19. 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)

  20. Orthogonal Control of Antibacterial Activity with Light

    NARCIS (Netherlands)

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

    2014-01-01

    Selection of a single bacterial strain out of a mixture of microorganisms is of crucial importance in healthcare and microbiology research. Novel approaches that can externally control bacterial selection are a valuable addition to the microbiology toolbox. In this proof-of-concept, two complementar

  1. Broadband Radiation Modes: Estimation and Active Control

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2002-01-01

    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. Be

  2. 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.

  3. Intraoperative Flap Complications in LASIK Surgery Performed by Ophthalmology Residents

    Science.gov (United States)

    Romero-Diaz-de-Leon, Lorena; Serna-Ojeda, Juan Carlos; Navas, Alejandro; Graue-Hernández, Enrique O.; Ramirez-Miranda, Arturo

    2016-01-01

    Purpose: To report the rate of flap-related complications in LASIK surgery performed by in-training ophthalmology residents and to analyze the risk factors for these complications. Methods: We analyzed 273 flap dissections in 145 patients from March 2013 to February 2014. We included all LASIK surgeries performed by 32 ophthalmology residents using a Moria M2 microkeratome. All the flap-related complications were noted. Comparison between both groups with and without complications was performed with an independent Student's t-test and relative risks were calculated. Results: There were 19 flap-related complications out of the 273 flap dissections (6.95%). The most common complication was incomplete flap dissection (n = 10; 3.66%), followed by free-cap (n = 5; 1.83%), and flap-buttonhole (n = 2; 0.73%). There was no significant difference between the complicated and uncomplicated cases in terms of the right versus the left eye, pachymetry results, white-to-white diameter, and spherical equivalent. But this difference was significant for mean keratometry (P = 0.008), K-min (P = 0.01), and K-max (P = 0.03) between these groups. Final visual acuity after rescheduling laser treatment was similar in both groups. Relative risks for flap-related complications were 2.03 for the first LASIK surgery (CI 95% 0.64 to 6.48; P = 0.22) and 1.26 (CI 95% 0.43 to 3.69; P = 0.66) for the surgeon's flap-related complications. Female gender presented an odds ratio of 2.48 (CI 95% 0.68 to 9.00; P = 0.16) for complications. 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. PMID:27621782

  4. The application of island myocutaneous flap for challenging wounds on cervico-thoracic region

    Institute of Scientific and Technical Information of China (English)

    XING Xin; XUE Chun-yu; LI Li; HUAN Jing-ning; GUO En-tan

    2006-01-01

    Objective:To introduce the experiences in the application of island myocutaneous flap for challenging wound on cervico-thoracic region. Methods: Different myocutaneous flaps were selected according to the location, peculiarity and etiological factor of wound. There were 28 cases of island pectoralis major island myocutanuous flaps, 34 cases of latissimus dorsi island myocutaneous flaps, 19 cases of trapizius island myocutaneous flaps and 17 cases of rectus abdominis island myocutaneous flaps in this report. Results: All 98 patients with challenging wound on cervico-thoracic region were successfully treated with this method without complications, and obtained functional and cosmetic effectiveness. Conclusion:Challenging wounds in cervico-nuchal region can be repaired with pertoralis major island myocutaneous flap, latissimus dorsi island myocutaneous flap and trapizius island myocutaneous flap, while challenging wounds in thoracic region can be repaired with latissimus dorsi island myocutaneous flap and rectus abdominis island myocutaneous flap. Satisfactory functional and cosmetic results can be obtained.

  5. An electronic control for an electrohydraulic active control landing gear for the F-4 aircraft

    Science.gov (United States)

    Ross, I.

    1982-01-01

    A controller for an electrohydraulic active control landing gear was developed for the F-4 aircraft. A controller was modified for this application. Simulation results indicate that during landing and rollout over repaired bomb craters the active gear effects a force reduction, relative to the passive gear, or approximately 70%.

  6. Geometric control of active collective motion

    CERN Document Server

    Theillard, Maxime; Saintillan, David

    2016-01-01

    Recent experimental studies have shown that confinement can profoundly affect self-organization in semi-dilute active suspensions, leading to striking features such as the formation of steady and spontaneous vortices in circular domains and the emergence of unidirectional pumping motions in periodic racetrack geometries. Motivated by these findings, we analyze the two-dimensional dynamics in confined suspensions of active self-propelled swimmers using a mean-field kinetic theory where conservation equations for the particle configurations are coupled to the forced Navier-Stokes equations for the self-generated fluid flow. In circular domains, a systematic exploration of the parameter space casts light on three distinct states: equilibrium with no flow, stable vortex, and chaotic motion, and the transitions between these are explained and predicted quantitatively using a linearized theory. In periodic racetracks, similar transitions from equilibrium to net pumping to traveling waves to chaos are observed in ag...

  7. Thick-osteochondral Flap Deepening Trochleoplasty for Patellar Instability

    Science.gov (United States)

    Donel, Simon; Ali, Khameinei; Smith, Dr. Tobi; McNamara, Iain

    2016-01-01

    Aims and Objectives: In patients with patellar instability and severe trochlear dysplasia, trochleoplasty has become increasingly used as part of the surgical management. The aim to report the mid-term results of this trochleoplasty including the sports and exercise activities of the cohort. Our hypothesis was that the operation would improve knee function and lead to an increase in sports participation in the patients. Materials and Methods: Between 1995 and 2010 the thick-flap deepening trochleoplasty was performed in 90 patients (107 knees) with severe trochlear dysplasia. Data was collected prospectively pre-operatively, at 6 weeks and 1-year follow-up. A standard pre-operative clinical assessment that included assessment of patellar apprehension , patellar tracking and patellofemoral crepitus. Post-operative outcome scores were performed by postal questionnaire and collected between June and December 2013, to determine the clinical and functional outcomes, including sports and exercise participation at a minimum of 2 years, with complete data available in 92%. Results: With a minimum follow-up of 2 years, average of 6 years (range 2 to 19 years). The Kujala score had a median and interquartile range (IQR) of 63 (47-75) pre-operatively rising to 79 (68-91) at 1 year follow-up and 84 (73-92) at final follow-up (pbadminton), participation increased from 16 (18%) to 22 (24%), whereas non-twisting sports (e.g. running, swimming, cycling) increased from 24 (27%) to 47 (52%) of whom 14 (16%) used walking as exercise. Conclusion: The thick-flap deepening trochleoplasty improves the clinical and functional outcomes for patients with symptomatic patellar instability with severe trochlear dysplasia. These results improve over time and beyond the 1 year clinical follow-up. However trochleoplasty does not lead to a significant improvement in sports participation at a competitive level. It does improve the sports and exercise patient participation, principally in non

  8. Activity meters permitting direct activity readings for food controls

    International Nuclear Information System (INIS)

    Instruments for total gamma activity measurements can only be used, if the calibration factor is known for the radionuclide mixture to be measured in each case. This is determined using spectroscopes calibrated on the basis of reference samples. Inaccuracies of measurement performed on equal volumes are caused by the fact that specific weights vary between foodstuffs and must therefore be made up for by adequate adjustments. As any radioactivity occurring naturally in the specimens cannot be distinguished from manmade radioactivity, it may be impossible to interpret results lower than some 100 Bq/kg for certain samples influenced by potassium (legume, dry milk) or uranium-radium (soil). The instruments incorporate annular receptacles for the samples and NaI(Tl) detectors for the measurement of gamma-emitting radionuclides in liquids, plant materials and foodstuffs, which have a reading for such activities in Bq/l or Bq/kg (Becquerel monitors). (orig./DG)

  9. A reduced energy supply strategy in active vibration control

    International Nuclear Information System (INIS)

    In this paper, a control strategy is presented and numerically tested. This strategy aims to achieve the potential performance of fully active systems with a reduced energy supply. These energy needs are expected to be comparable to the power demands of semi-active systems, while system performance is intended to be comparable to that of a fully active configuration. The underlying strategy is called 'global semi-active control'. This control approach results from an energy investigation based on management of the optimal control process. Energy management encompasses storage and convenient restitution. The proposed strategy monitors a given active law without any external energy supply by considering purely dissipative and energy-demanding phases. Such a control law is offered here along with an analysis of its properties. A suboptimal form, well adapted for practical implementation steps, is also given. Moreover, a number of numerical experiments are proposed in order to validate test findings

  10. Linear Quadratic Integral Control for the Active Suspension of Vehicle

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The quarter model of an active suspension is established in the form of controllable autoregressive moving average (CARMA) model. An accelerometer can be mounted on the wheel hub for measuring road disturbance; this signal is used to identify the CARMA model parameters by recursive forgetting factors least square method. The linear quadratic integral (LQI) control method for the active suspension is presented. The LQI control algorithm is fit for vehicle suspension control, for the control performance index can comprise multi controlled variables. The simulation results show that the vertical acceleration and suspension travel both are decreased with the LQI control in the low frequency band, and the suspension travel is increased with the LQI control in the middle or high frequency band. The suspension travel is very small in the middle or high frequency band, the suspension bottoming stop will not happen, so the vehicle ride quality can be improved apparently by the LQI control.

  11. Fenestration of bone flap during interval autologous cranioplasty

    Directory of Open Access Journals (Sweden)

    Ha Son Nguyen

    2015-01-01

    Conclusion: Presumably, fenestrations augment surface area for extra-axial fluid absorption through the bone flap. Our results, regarding MLS and postoperative volume, provide support for this concept. Accordingly, bone flap fenestration has the potential to reduce extra-axial fluid accumulation.

  12. Breast ptosis managed by mastopexy using the triple flaps procedure.

    Science.gov (United States)

    Gheita, Alaa; Moftah, Ali

    2011-02-01

    Breast ptosis is a highly unattractive appearance of the breast. In the mind, it is associated with aging, multiple pregnancies, lactation, and senile changes. Its correction by mastopexy presents one of the greatest challenges to the breast surgeon aiming at a pleasant full conical shape and stability of the results. The authors present their mastopexy procedure using a triple-flap method based on the principle of a superior pedicle flap mammaplasty. The technique, presented in detail, basically consists of a superior pedicle dermaglandular flap that carries the nipple-areola complex between outer and inner flaps. The outer flap is rotated inward and upward behind the main superior pedicle to give fullness to the breast and fixed to the chest wall. The inner flap is double-breasted on top or superficial to outer flap, and both are sutured to each other resembling a hammock or a cradle that carries the main superior pedicle middle flap. The results are presented and advantages discussed. This method, besides its simplicity, gives good projection with a pleasant and attractive conical shape to the breast and upper fullness, frequently negating the need for an implant. In addition, the results were stable in the long term, with no need for a mesh or any other foreign material. PMID:20652567

  13. Repair of large palatal fistula using tongue flap

    Directory of Open Access Journals (Sweden)

    Fejjal Nawfal

    2014-01-01

    Full Text Available Large palatal fistulas are a challenging problem in cleft surgery. Many techniques are used to close the defect. The tongue flap is an easy and reproductible procedure for managing this complication. The authors report a case of a large palatal fistula closure with anteriorly based tongue flap.

  14. 14 CFR 25.701 - Flap and slat interconnection.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Flap and slat interconnection. 25.701....701 Flap and slat interconnection. (a) Unless the airplane has safe flight characteristics with the... sides of the plane of symmetry must be synchronized by a mechanical interconnection or...

  15. Oral functional outcome after intraoral reconstruction with nasolabial flaps

    NARCIS (Netherlands)

    Hofstra, EI; Hofer, SOP; Nauta, JM; Roodenburg, JLN; Lichtendahl, DHE

    2004-01-01

    In this study, the functional and aesthetic outcome of patients with nasolabial flaps in the floor of the mouth was examined. Sixteen patients underwent reconstruction of the floor of the mouth with 19 nasolabial flaps after resection of a squamous cell carcinoma. Eight patients received postoperati

  16. Dorsalis pedis arterialized venous flap for hand and foot reconstruction

    Institute of Scientific and Technical Information of China (English)

    YU Guang; LEI Hong-yu; GUO Shuang; HUANG Jian-hua; YU Hao

    2012-01-01

    Objective:To report the results of repair of skin defects in the extremities with arterialized venous flap harvested from the lateral aspect of the dorsum of the foot.Methods:Six cases of skin and soft tissue defects over the foot and hands were resurfaced by free arterialized venous flaps,including five patients with skin defects of the hands,and one with defects at the dorsum of the foot.The flaps were harvested from the lateral aspect of the dorsum of the foot with the sizes ranging from 2 cm×5.5 cm to 6 cm×11 cm.Two veins at the proximal margin of the flap were retained,one of which was anastomosed to a recipient bed artery to provide arterial inflow and the other was anastomosed to a recipient bed vein for venous outflow.Results:All flaps demonstrated mild edema and survived completely.Blisters appeared on four flaps.Using this technique,we achieved good functional and cosmetic results in this series.Conclusions:Dorsalis pedis arterialized venous flap with rich vascular communications could enhance peripheral perfusion and decrease congestion of venous flaps,thereby improves reliability and utility for extremity reconstruction.

  17. 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.

  18. Preoperative CT angiography reduces surgery time in perforator flap reconstruction

    NARCIS (Netherlands)

    Smit, Jeroen M.; Dimopoulou, Angeliki; Liss, Anders G.; Zeebregts, Clark J.; Kildal, Morten; Whitaker, Iain S.; Magnusson, Anders; Acosta, Rafael

    2009-01-01

    The use of perforator flaps in breast reconstructions has increased considerably in the past decade. A disadvantage of the perforator flap is difficult dissection, which results in a longer procedure. During spring 2006, we introduced CT angiography (CTA) as part of the diagnostic work-up in perfora

  19. Perforator propeller flaps for sacral and ischial soft tissue reconstruction

    Directory of Open Access Journals (Sweden)

    Korambayil Pradeoth

    2010-01-01

    Full Text Available The perforator-based flaps in the sacral and ischial region is designed according to the localization of perforators that penetrate the gluteus maximus muscle, reach the intra-fascial and supra-fascial planes with the overlying skin forming a rich vascular plexus. The perforator-based flaps described in this article are highly vascularized, have minimal donor site morbidity, and do not require the sacrifice of the gluteus maximus muscle. In a period between April 2008 and March 2009, six patients with sacral pressure sore were reconstructed with propeller flap method based on superior gluteal and parasacral artery perforators. One flap loss was noted. Three cases of ischial pressure sore were reconstructed with longitudinal propeller flap cover, based on inferior gluteal artery perforator. One flap suffered wound infection and dehiscence. Two cases of pilonidal sinus were reconstructed with propeller flap based on parasacral perforators. Both the flaps survived without any complications. Donor sites were closed primarily. In the light of this, they can be considered among the first surgical choices to re-surface soft tissue defects of the sacral and ischial regions. In the series of 11 patients, two patients (18% suffered complications.

  20. Perforator propeller flaps for sacral and ischial soft tissue reconstruction

    Science.gov (United States)

    Korambayil, Pradeoth M.; Allalasundaram, KV; Balakrishnan, TM

    2010-01-01

    The perforator-based flaps in the sacral and ischial region is designed according to the localization of perforators that penetrate the gluteus maximus muscle, reach the intra-fascial and supra-fascial planes with the overlying skin forming a rich vascular plexus. The perforator-based flaps described in this article are highly vascularized, have minimal donor site morbidity, and do not require the sacrifice of the gluteus maximus muscle. In a period between April 2008 and March 2009, six patients with sacral pressure sore were reconstructed with propeller flap method based on superior gluteal and parasacral artery perforators. One flap loss was noted. Three cases of ischial pressure sore were reconstructed with longitudinal propeller flap cover, based on inferior gluteal artery perforator. One flap suffered wound infection and dehiscence. Two cases of pilonidal sinus were reconstructed with propeller flap based on parasacral perforators. Both the flaps survived without any complications. Donor sites were closed primarily. In the light of this, they can be considered among the first surgical choices to re-surface soft tissue defects of the sacral and ischial regions. In the series of 11 patients, two patients (18%) suffered complications. PMID:21217972

  1. Clinical study of dorsal ulnar artery flap in hand reconstruction

    Directory of Open Access Journals (Sweden)

    Khan Manal

    2009-01-01

    Full Text Available Soft tissue defects of hand with exposed tendons, joints, nerves and bone represent a challenge to plastic surgeons. Such defects necessitate early flap coverage to protect underlying vital structures, preserve hand functions and to allow for early rehabilitation. Becker and Gilbert described flap based on the dorsal branch of the ulnar artery for defects around the wrist. We evaluated the use of a dorsal ulnar artery island flap in patients with soft tissue defects of hand. Twelve patients of soft tissue defects of hand underwent dorsal ulnar artery island flap between August 2006 and May 2008. In 10 male and 2 female patients this flap was used to reconstruct defects of the palm, dorsum of hand and first web space. Ten flaps survived completely. Marginal necrosis occurred in two flaps. In one patient suturing was required after debridement and in other patient wound healed by secondary intention. The final outcome was satisfactory. Donor areas which were skin grafted, healed with acceptable cosmetic results. The dorsal ulnar artery island flap is convenient, reliable, and easy to manage and is a single-stage technique for reconstructing soft tissue defects of the palm, dorsum of hand and first web space. Donor site morbidity is minimal, either closed primarily or covered with split thickness skin graft.

  2. The effect of wing stroke and aspect ratio on the force generation a compliant membrane flapping wing

    Science.gov (United States)

    Schunk, Cosima; Swartz, Sharon M.; Breuer, Kenneth S.

    2015-11-01

    Aspect ratio is one parameter used in efforts to predict a bat species' flight performance based on wing shape. Bats with high aspect ratio wings are expected to have superior lift-to-drag ratios and therefore to fly faster or be able to sustain longer flights. In contrast, bats with lower aspect ratio wings are usually thought to exhibit higher maneuverability. These assumptions are often based on fixed-wing aerodynamic theory, and do not take the wide variation in flapping kinematics observed in bats into account. To examine the influence of different stroke patterns, we measure lift and drag of highly compliant membrane wings with different bat-relevant aspect ratios. A two degree of freedom shoulder joint allows for independent control of flapping amplitude and wing sweep. We test five models with the same variations of stroke patterns, flapping frequencies, and wind speeds.

  3. Active Vibration Control of Satellite Flexible Structures during Attitude Maneuvers

    OpenAIRE

    Saeed Hemmati; Morteza Shahravi; Keramat Malekzadeh

    2013-01-01

    The purpose of this study is controlling active vibration of satellite flexible structures during attitude maneuvers. A smart structure is a structure which is able to sense and control active reaction to any external factors and stimulation. As it comes from the definition of smart structures, development of this knowledge depends on the materials science development, theories and strategies for control. In materials science, smart materials are developed in such a way that they are able to ...

  4. An active control synchronization for two modified Chua circuits

    Science.gov (United States)

    Li, Guo-Hui

    2005-03-01

    From modern control theory, an active control method to synchronize two modified Chua circuits with each other, which exhibit chaos, is presented. Some sufficient conditions of linear stability of the chaotic synchronization are obtained from rigorous mathematic justification. On the basis of the state-observer, the controller is analytically deduced using the active control. It is shown that this technique can be applied to achieve synchronization of the two systems with each other, whether they are identical or not. Finally, numerical simulations show the effectiveness of the proposed control scheme.

  5. 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...... 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...

  6. An active control synchronization for two modified Chua circuits

    Institute of Scientific and Technical Information of China (English)

    Li Guo-Hui

    2005-01-01

    From modern control theory, an active control method to synchronize two modified Chua circuits with each other, which exhibit chaos, is presented. Some sufficient conditions of linear stability of the chaotic synchronization are obtained from rigorous mathematic justification. On the basis of the state-observer, the controller is analytically deduced using the active control. It is shown that this technique can be applied to achieve synchroniztion of the tow systems with each other, whether they are identical or not. Finally, numerical simulations show the effectiveness of the proposed control scheme.

  7. STATISTIC LINEARIZATION CONTROL FOR HYDRAULIC ACTIVE DAMPING SUSPENSION

    Institute of Scientific and Technical Information of China (English)

    Wang Qingfeng; Zhao Ju; Yang Botao

    2000-01-01

    A statistic linearization analysis method of bad nolinear hydraulic active damping suspensiop is provided.Also the optimum control strategy of semi-active suspension and graded control strategy based on it are puted forward.Experimental researches are carried out on a 2 DOF (degree of freedom ) hydraulic active damping suspension test system.The results showed that an excellent control effectiveness could be obtained by using statistic linearization optimum control which unfortunely requests continuously regulationg the damp in an accurate way and costs much in engeering application.On the contrary,the results also showed that graded control is more practicable which has a control effectiveness close to the optimum control and costs less.

  8. Controlling the enzymatic activity of a restriction enzyme by light

    OpenAIRE

    Schierling, Benno; Noël, Ann-Josée; Wende, Wolfgang; Hien, Le Thi; Volkov, Eugeny; Kubareva, Elena; Oretskaya, Tatiana; Kokkinidis, Michael; Römpp, Andreas; Spengler, Bernhard; Pingoud, Alfred

    2009-01-01

    For many applications it would be desirable to be able to control the activity of proteins by using an external signal. In the present study, we have explored the possibility of modulating the activity of a restriction enzyme with light. By cross-linking two suitably located cysteine residues with a bifunctional azobenzene derivative, which can adopt a cis- or trans-configuration when illuminated by UV or blue light, respectively, enzymatic activity can be controlled in a reversible manner. T...

  9. An Overview of Active Structural Control under Seismic Loads

    OpenAIRE

    Soong, T.T.; Masri, S. F.; Housner, G. W.

    1991-01-01

    The concept of active structural control as a means of structural protection against seismic loads, developed over the last 20 years, has received considerable attention in recent years. It has now reached the stage where active systems have been installed in full-scale structures. It is the purpose of this paper to provide an overview of this development with special emphasis placed on laboratory experiments using model structures and on full-scale implementation of some active control syste...

  10. Active control of tiltrotor blade in-plane loads during maneuvers

    Science.gov (United States)

    Miller, David G.; Ham, Norman D.

    1988-01-01

    The origin of one/rev rotor aerodynamic loads which arise in tiltrotor aircraft during airplane-mode high speed pull-up and push-over maneuvers is examined using a coupled rotor/fuselage dynamic simulation. A modified eigenstructure assignment technique is used to design a controller which alleviates the in-plane loads during high pitch rate maneuvers. The controller utilizes rotor cyclic pitch inputs to restructure the aircraft short period and phugoid responses in order to achieve the coupling between pitch rate and rotor flapping responses which minimizes the rotor aerodynamic loading. Realistic time delays in the feedback path are considered during the controller design. Stability robustness in the presence of high frequency modeling errors is ensured through the use of singular value analysis.

  11. A Case Report on Bilateral Knee Coverage Following Septic Arthritis: Lateral Distal Thigh Island Flap and Medial Head Gastrocnemius Flap Methods

    Directory of Open Access Journals (Sweden)

    Abdolrazaghi

    2016-03-01

    Full Text Available Introduction Septic arthritis is the rheumatological and orthopedic emergency that causes the most difficulties with joints–especially knee and hip joints. The clinical symptoms include pain, swelling, inflammation, stiffness, and a limited range of motion in both active and passive joints. Debridement of the necrotic tissue is one beneficial method for septic arthritis treatment, although soft tissue defects around joints are a challenging issue for surgeons. Our purpose was to investigate the consequences of two flap surgery methods undertaken to repair soft tissue damaged during knee joint debridement caused by septic arthritis. Case Presentation This is a case report concerning a patient who had septic arthritis in the knee area and so underwent soft tissue surgery. The reconstruction methods were not the same for both knees as the lateral distal thigh island flap reparation method was used on the left knee and the medial head gastrocnemius flap method was utilized on the right. We then investigated the results and outcomes of the surgery three months later. Conclusions Lower extremity movement extent was carefully evaluated and, in respect to muscle strength, the patient was able to walk independently three months after the surgery. The patient’s balance was studied and the results showed moderate levels of stability.

  12. Propeller Flaps: A Review of Indications, Technique, and Results

    Science.gov (United States)

    D'Arpa, Salvatore; Toia, Francesca; Pirrello, Roberto; Moschella, Francesco; Cordova, Adriana

    2014-01-01

    In the last years, propeller flaps have become an appealing option for coverage of a large range of defects. Besides having a more reliable vascular pedicle than traditional flap, propeller flaps allow for great freedom in design and for wide mobilization that extend the possibility of reconstructing difficult wounds with local tissues and minimal donor-site morbidity. They also allow one-stage reconstruction of defects that usually require multiple procedures. Harvesting of a propeller flap requires accurate patient selection, preoperative planning, and dissection technique. Complication rate can be kept low, provided that potential problems are prevented, promptly recognized, and adequately treated. This paper reviews current knowledge on propeller flaps. Definition, classification, and indications in the different body regions are discussed based on a review of the literature and on the authors' experience. Details about surgical technique are provided, together with tips to avoid and manage complications. PMID:24971367

  13. Propeller Flaps: A Review of Indications, Technique, and Results

    Directory of Open Access Journals (Sweden)

    Salvatore D'Arpa

    2014-01-01

    Full Text Available In the last years, propeller flaps have become an appealing option for coverage of a large range of defects. Besides having a more reliable vascular pedicle than traditional flap, propeller flaps allow for great freedom in design and for wide mobilization that extend the possibility of reconstructing difficult wounds with local tissues and minimal donor-site morbidity. They also allow one-stage reconstruction of defects that usually require multiple procedures. Harvesting of a propeller flap requires accurate patient selection, preoperative planning, and dissection technique. Complication rate can be kept low, provided that potential problems are prevented, promptly recognized, and adequately treated. This paper reviews current knowledge on propeller flaps. Definition, classification, and indications in the different body regions are discussed based on a review of the literature and on the authors’ experience. Details about surgical technique are provided, together with tips to avoid and manage complications.

  14. Vaginal reconstruction using perineal-thigh flaps with subcutaneous pedicle.

    Science.gov (United States)

    Chen, Z; Chen, C; Chen, M; Zhang, J; Wu, N; Wang, J

    1991-03-01

    A technique of vaginal reconstruction using bilateral, perineal-thigh flaps with subcutaneous pedicle is described. In this procedure, the flaps were raised bilaterally and introduced into an artificial space between the urinary bladder and rectum. The blood supply for the flaps flows from the perineal artery through anastomotic branches to the external pudendal artery. The authors used the technique on four patients, and all the flaps survived entirely. There was no complication. According to a more than two-year follow-up survey, the reconstructed vaginas are expansible and contract little. No stent is needed. There is good sensitivity in the wall of the artificial vagina because sensory nerves run through the flaps.

  15. Generalized Internal Model Robust Control for Active Front Steering Intervention

    Institute of Scientific and Technical Information of China (English)

    WU Jian; ZHAO Youqun; JI Xuewu; LIU Yahui; ZHANG Lipeng

    2015-01-01

    Because of the tire nonlinearity and vehicle’s parameters’ uncertainties, robust control methods based on the worst cases, such as H∞, μsynthesis, have been widely used in active front steering control, however, in order to guarantee the stability of active front steering system (AFS) controller, the robust control is at the cost of performance so that the robust controller is a little conservative and has low performance for AFS control. In this paper, a generalized internal model robust control (GIMC) that can overcome the contradiction between performance and stability is used in the AFS control. In GIMC, the Youla parameterization is used in an improved way. And GIMC controller includes two sections:a high performance controller designed for the nominal vehicle model and a robust controller compensating the vehicle parameters’ uncertainties and some external disturbances. Simulations of double lane change (DLC) maneuver and that of braking on split-μroad are conducted to compare the performance and stability of the GIMC control, the nominal performance PID controller and the H∞ controller. Simulation results show that the high nominal performance PID controller will be unstable under some extreme situations because of large vehicle’s parameters variations, H∞ controller is conservative so that the performance is a little low, and only the GIMC controller overcomes the contradiction between performance and robustness, which can both ensure the stability of the AFS controller and guarantee the high performance of the AFS controller. Therefore, the GIMC method proposed for AFS can overcome some disadvantages of control methods used by current AFS system, that is, can solve the instability of PID or LQP control methods and the low performance of the standard H∞controller.

  16. Experimental investigation of a flapping wing model

    Science.gov (United States)

    Hubel, Tatjana Y.; Tropea, Cameron

    The main objective of this research study was to investigate the aerodynamic forces of an avian flapping wing model system. The model size and the flow conditions were chosen to approximate the flight of a goose. Direct force measurements, using a three-component balance, and PIV flow field measurements parallel and perpendicular to the oncoming flow, were performed in a wind tunnel at Reynolds numbers between 28,000 and 141,000 (3-15 m/s), throughout a range of reduced frequencies between 0.04 and 0.20. The appropriateness of quasi-steady assumptions used to compare 2D, time-averaged particle image velocimetry (PIV) measurements in the wake with direct force measurements was evaluated. The vertical force coefficient for flapping wings was typically significantly higher than the maximum coefficient of the fixed wing, implying the influence of unsteady effects, such as delayed stall, even at low reduced frequencies. This puts the validity of the quasi-steady assumption into question. The (local) change in circulation over the wing beat cycle and the circulation distribution along the wingspan were obtained from the measurements in the tip and transverse vortex planes. Flow separation could be observed in the distribution of the circulation, and while the circulation derived from the wake measurements failed to agree exactly with the absolute value of the circulation, the change in circulation over the wing beat cycle was in excellent agreement for low and moderate reduced frequencies. The comparison between the PIV measurements in the two perpendicular planes and the direct force balance measurements, show that within certain limitations the wake visualization is a powerful tool to gain insight into force generation and the flow behavior on flapping wings over the wing beat cycle.

  17. Study of tethered satellite active attitude control

    Science.gov (United States)

    Colombo, G.

    1982-01-01

    Existing software was adapted for the study of tethered subsatellite rotational dynamics, an analytic solution for a stable configuration of a tethered subsatellite was developed, the analytic and numerical integrator (computer) solutions for this "test case' was compared in a two mass tether model program (DUMBEL), the existing multiple mass tether model (SKYHOOK) was modified to include subsatellite rotational dynamics, the analytic "test case,' was verified, and the use of the SKYHOOK rotational dynamics capability with a computer run showing the effect of a single off axis thruster on the behavior of the subsatellite was demonstrated. Subroutines for specific attitude control systems are developed and applied to the study of the behavior of the tethered subsatellite under realistic on orbit conditions. The effect of all tether "inputs,' including pendular oscillations, air drag, and electrodynamic interactions, on the dynamic behavior of the tether are included.

  18. A Novel Degree of Freedom in Flapping Wings Shows Promise for a Dual Aerial/Aquatic Vehicle Propulsor

    CERN Document Server

    Izraelevitz, Jacob S

    2014-01-01

    Ocean sampling for highly temporal phenomena, such as harmful algal blooms, necessitates a vehicle capable of fast aerial travel interspersed with an aquatic means of acquiring in-situ measurements. Vehicle platforms with this capability have yet to be widely adopted by the oceanographic community. Several animal examples successfully make this aerial/aquatic transition using a flapping foil actuator, offering an existence proof for a viable vehicle design. We discuss a preliminary realization of a flapping wing actuation system for use in both air and water. The wing employs an active in-line motion degree of freedom to generate the large force envelope necessary for propulsion in both fluid media.

  19. Reconstructive Surgery for Severe Penile Inadequacy: Phalloplasty with a Free Radial Forearm Flap or a Pedicled Anterolateral Thigh Flap

    Directory of Open Access Journals (Sweden)

    N. Lumen

    2008-01-01

    Full Text Available Objectives. Severe penile inadequacy in adolescents is rare. Phallic reconstruction to treat this devastating condition is a major challenge to the reconstructive surgeon. Phallic reconstruction using the free radial forearm flap (RFF or the pedicled anterolateral thigh flap (ALTF has been routinely used in female-to-male transsexuals. Recently we started to use these techniques in the treatment of severe penile inadequacy. Methods. Eleven males (age 15 to 42 years were treated with a phallic reconstruction. The RFF is our method of choice; the ALTF is an alternative when a free flap is contraindicated or less desired by the patient. The RFF was used in 7 patients, the ALTF in 4 patients. Mean followup was 25 months (range: 4–49 months. Aesthetic and functional results were evaluated. Results. There were no complications related to the flap. Aesthetic results were judged as “good” in 9 patients and “moderate” in 2 patients. Sensitivity in the RFF was superior compared to the ALTF. Four patients developed urinary complications (stricture and/or fistula. Six patients underwent erectile implant surgery. In 2 patients the erectile implant had to be removed due to infection or erosion. Conclusion. In case of severe penile inadequacy due to whatever condition, a phalloplasty is the preferred treatment nowadays. The free radial forearm flap is still the method of choice. The anterolateral thigh flap can be a good alternative, especially when free flaps are contraindicated, but sensitivity is markedly inferior in these flaps.

  20. Active structural control with stable fuzzy PID techniques

    CERN Document Server

    Yu, Wen

    2016-01-01

    This book presents a detailed discussion of intelligent techniques to measure the displacement of buildings when they are subjected to vibration. It shows how these techniques are used to control active devices that can reduce vibration 60–80% more effectively than widely used passive anti-seismic systems. After introducing various structural control devices and building-modeling and active structural control methods, the authors propose offset cancellation and high-pass filtering techniques to solve some common problems of building-displacement measurement using accelerometers. The most popular control algorithms in industrial settings, PD/PID controllers, are then analyzed and then combined with fuzzy compensation. The stability of this combination is proven with standard weight-training algorithms. These conditions provide explicit methods for selecting PD/PID controllers. Finally, fuzzy-logic and sliding-mode control are applied to the control of wind-induced vibration. The methods described are support...

  1. HYBRID FUZZY CONTROL FOR ELECTRO-HYDRAULIC ACTIVE DAMPING SUSPENSION

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A new control scheme, the hybrid fuzzy control method, for active damping suspension system is presented. The scheme is the result of effective combination of the statistical optimal control method based on the statistical property of suspension system, with the bang-bang control method based on the real-time characteristics of suspension system. Computer simulations are performed to compare the effectiveness of hybrid fuzzy control scheme with that of optimal damping control, bang-bang control, and passive suspension. It takes the effects of time-variant factors into full account. The superiority of the proposed hybrid fuzzy control scheme for active damping suspension to the passive suspension is verified in the experiment study.

  2. Adaptive Current Control with PI-Fuzzy Compound Controller for Shunt Active Power Filter

    Directory of Open Access Journals (Sweden)

    Juntao Fei

    2013-01-01

    Full Text Available An adaptive control technology and PI-fuzzy compound control technology are proposed to control an active power filter (APF. AC side current compensation and DC capacitor voltage tracking control strategy are discussed and analyzed. Model reference adaptive controller for the AC side current compensation is derived and established based on Lyapunov stability theory; proportional and integral (PI fuzzy compound controller is designed for the DC side capacitor voltage control. The adaptive current controller based on PI-fuzzy compound system is compared with the conventional PI controller for active power filter. Simulation results demonstrate the feasibility and satisfactory performance of the proposed control strategies. It is shown that the proposed control method has an excellent dynamic performance such as small current tracking error, reduced total harmonic distortion (THD, and strong robustness in the presence of parameters variation and nonlinear load.

  3. Application of skin flaps transplantation in burn surgery in China%皮瓣移植在我国烧伤外科中的应用

    Institute of Scientific and Technical Information of China (English)

    黄晓元

    2008-01-01

    The history and application of surgical flap transplantation in burn wound were briefly reviewed. We outlined skin flap, muscuiocutaneous flap, fascia flap and neurocutaneous vascular flap in this paper and recommended repair deep wounds with flap. All in all, in this review, we hope to provide a meaningful option for clinical application of surgical flap in the future.

  4. Various applications of Active Field Control (AFC)

    Science.gov (United States)

    Watanabe, Takayuki; Miyazaki, Hideo; Kishinaga, Shinji; Kawakami, Fukushi

    2003-10-01

    AFC is an electro-acoustic enhancement system, which has been under development at Yamaha Corporation. In this paper, several types of various AFC applications are discussed, while referring to representative projects for each application in Japan. (1) Realization of acoustics in a huge hall to classical music program, e.g., Tokyo International Forum. This venue is a multipurpose hall with approximately 5000 seats. AFC achieves loudness and reverberance equivalent to those of a hall with 2500 seats or fewer. (2) Optimization of acoustics for a variety of programs, e.g., Arkas Sasebo. AFC is used to create the optimum acoustics for each program, such as reverberance for classical concerts, acoustical support for opera singers, uniformity throughout the hall from the stage to under-balcony area, etc. (3) Control of room shape acoustical effect, e.g., Osaka Central Public Hall: In this renovation project, preservation of historically important architecture in the original form is required. AFC is installed to vary only the acoustical environment without architectural changes. (4) Assistance with crowd enthusiasm for sports entertainment, e.g., Tokyo Metropolitan Gymnasium. In this venue, which is designed as a very absorptive space for speech intelligibility, AFC is installed to enhance the atmosphere of live sports entertainment.

  5. Active and passive stabilization of body pitch in insect flight.

    Science.gov (United States)

    Ristroph, Leif; Ristroph, Gunnar; Morozova, Svetlana; Bergou, Attila J; Chang, Song; Guckenheimer, John; Wang, Z Jane; Cohen, Itai

    2013-08-01

    Flying insects have evolved sophisticated sensory-motor systems, and here we argue that such systems are used to keep upright against intrinsic flight instabilities. We describe a theory that predicts the instability growth rate in body pitch from flapping-wing aerodynamics and reveals two ways of achieving balanced flight: active control with sufficiently rapid reactions and passive stabilization with high body drag. By glueing magnets to fruit flies and perturbing their flight using magnetic impulses, we show that these insects employ active control that is indeed fast relative to the instability. Moreover, we find that fruit flies with their control sensors disabled can keep upright if high-drag fibres are also attached to their bodies, an observation consistent with our prediction for the passive stability condition. Finally, we extend this framework to unify the control strategies used by hovering animals and also furnish criteria for achieving pitch stability in flapping-wing robots.

  6. CLP activities and control in Ireland

    Directory of Open Access Journals (Sweden)

    Caroline Walsh

    2011-01-01

    Full Text Available The 10th December 2010 marked a new beginning for Regulation (EC no. 1272/2008 on the classification, labelling and packaging of substances and mixtures (CLP in Ireland with the start of its operational phase. It was on this date that the administrative and enforcement provisions for CLP were encompassed in the new Chemicals Amendment Act, 2010. In this Act, the Health and Safety Authority, known as the "the Authority" is named as Competent Authority (CA for CLP, along with the Minister for Agriculture, Fisheries and Food, in respect of pesticides and plant protection products and the Beaumont Hospital Board with responsibility for receiving information relating to emergency health response. In practice, the Authority has been de facto CA for CLP since its publication on the 31st December 2008, given its role in existing classification and labelling regimes. This article focuses on the work undertaken by the Authority on CLP at a National, European and International level including its implementation, training, helpdesk, guidance, enforcement and awareness raising activities.

  7. CLP activities and control in Ireland.

    Science.gov (United States)

    Walsh, Caroline

    2011-01-01

    The 10(th) December 2010 marked a new beginning for Regulation (EC) no. 1272/2008 on the classification, labelling and packaging of substances and mixtures (CLP) in Ireland with the start of its operational phase. It was on this date that the administrative and enforcement provisions for CLP were encompassed in the new Chemicals Amendment Act, 2010. In this Act, the Health and Safety Authority, known as the "the Authority" is named as Competent Authority (CA) for CLP, along with the Minister for Agriculture, Fisheries and Food, in respect of pesticides and plant protection products and the Beaumont Hospital Board with responsibility for receiving information relating to emergency health response. In practice, the Authority has been de facto CA for CLP since its publication on the 31(st) December 2008, given its role in existing classification and labelling regimes. This article focuses on the work undertaken by the Authority on CLP at a National, European and International level including its implementation, training, helpdesk, guidance, enforcement and awareness raising activities.

  8. Submental flap as an alternative to microsurgical flap in intraoral post-oncological reconstruction in the elderly.

    Science.gov (United States)

    Schonauer, Fabrizio; Di Martino, Annalena; Nele, Gisella; Santoro, Mariangela; Dell'Aversana Orabona, Giovanni; Califano, Luigi

    2016-09-01

    Oral and oropharyngeal squamous cell carcinoma (Scc) occur most commonly in middle-aged and elderly individuals. Free flaps are commonly used for reconstruction of extensive tumor resection defects in the oral cavity. Age alone is not an independent variable for increased risk in microvascular reconstruction; however operative time and ASA risk score correlated with medical complications but not with surgical complications. The submental island flap has proven to be a reliable alternative in reconstruction of composite oral cavity defects for its thinness, pliability and versatility in design, shared by the radial forearm free flap, and its advantageous donor site. The submental flap can be easily raised and involves shorter operative time and hospital stay compared to the free-flap procedure. It can be an excellent choice in patients with a high ASA risk score, moreover in elderly patients, where the potential complications linked to microsurgical procedures are avoided. PMID:27255573

  9. Wireless sensor networks for active vibration control in automobile structures

    Science.gov (United States)

    Mieyeville, Fabien; Ichchou, Mohamed; Scorletti, Gérard; Navarro, David; Du, Wan

    2012-07-01

    Wireless sensor networks (WSNs) are nowadays widely used in monitoring and tracking applications. This paper presents the feasibility of using WSNs in active vibration control strategies. The method employed here involves active-structural acoustic control using piezoelectric sensors distributed on a car structure. This system aims at being merged with a WSN whose head node collects data and processes control laws so as to command piezoelectric actuators wisely placed on the structure. We will study the feasibility of implementing WSNs in active vibration control and introduce a complete design methodology to optimize hardware/software and control law synergy in mechatronic systems. A design space exploration will be conducted so as to identify the best WSN platform and the resulting impact on control.

  10. Active Noise Feedback Control Using a Neural Network

    Directory of Open Access Journals (Sweden)

    Zhang Qizhi

    2001-01-01

    Full Text Available The active noise control (ANC is discussed. Many digital ANC systems often based on the filter-x algorithm for finite impulse response (FIR filter use adaptive filtering techniques. But if the primary noise path is nonlinear, the control system based on adaptive filter technology will be invalid. In this paper, an adaptive active nonlinear noise feedback control approach using a neural network is derived. The feedback control system drives a secondary signal to destructively interfere with the original noise to cut down the noise power. An on-line learning algorithm based on the error gradient descent method was proposed, and the local stability of closed loop system is proved using the discrete Lyapunov function. A nonlinear simulation example shows that the adaptive active noise feedback control method based on a neural network is very effective to the nonlinear noise control.

  11. Wireless sensor networks for active vibration control in automobile structures

    International Nuclear Information System (INIS)

    Wireless sensor networks (WSNs) are nowadays widely used in monitoring and tracking applications. This paper presents the feasibility of using WSNs in active vibration control strategies. The method employed here involves active-structural acoustic control using piezoelectric sensors distributed on a car structure. This system aims at being merged with a WSN whose head node collects data and processes control laws so as to command piezoelectric actuators wisely placed on the structure. We will study the feasibility of implementing WSNs in active vibration control and introduce a complete design methodology to optimize hardware/software and control law synergy in mechatronic systems. A design space exploration will be conducted so as to identify the best WSN platform and the resulting impact on control. (paper)

  12. Controlled physical activity for functional operability determination

    Directory of Open Access Journals (Sweden)

    Luchenkov А.А.

    2014-06-01

    Full Text Available The aim: to use veloergometry test at patients of high anaeshtesiology-operative risk before traumatic operations for functional operability determination. Material and methods: Randomized prospective research with the double "blind" control has been performed at 95 patients of high risk (ASA>III, undergoing long and traumatic operations on thoracic and abdominal organs. Patients have divided into groups without complications and with complications (51 and 44 patients which one day prior to operation have spent veloergometry test (VEMT. Average dynamic pressure (ADP, the general peripheral resistance of vessels (GPRV, a core index (Cl; arterio-venous (a-v difference on oxygen, oxygen delivery to tissues, consumption of oxygen and coefficients extraction oxygen in tissues; energy consumption have been investigated. Statistics has been done by nonparametric methods. Results. In response to veloergometry test in both groups growth of Cl at the expense of a tachycardia and GPRV fall which in complication group remains above norm is noted. In group without complications coefficients extraction oxygen in tissues were normalised, a-v difference on 02 became above norm, in other group — coefficients extraction oxygen in tissues and a-v difference on 02 began to exceed norm, and oxygen consumption has grown almost in 2 times. After VEMT a-v a difference on О and oxygen consumption were essentially above in group with complications. Under the influence of VEMT markecT stabilization of function of vegetative nervous systems (VNS. The number of complications made 39: intraoperation cardiovascular — 23, postoperative respiratory — 16. Clinically important connection (p=0,069 of perioperative complications with growth a-v differences on oxygen and a power interchanging have been received. Conclusion. Thus, the oxygen-energy exchange and the vegetative status can be referred to clinical functional operability determination.

  13. On-line Monitoring and Active Control for Transformer Noise

    Science.gov (United States)

    Liang, Jiabi; Zhao, Tong; Tian, Chun; Wang, Xia; He, Zhenhua; Duan, Lunfeng

    This paper introduces the system for on-line monitoring and active noise control towards the transformer noise based on LabVIEW and the hardware equipment including the hardware and software. For the hardware part, it is mainly focused on the composition and the role of hardware devices, as well as the mounting location in the active noise control experiment. And the software part introduces the software flow chats, the measurement and analysis module for the sound pressure level including A, B, C weighting methods, the 1/n octave spectrum and the power spectrum, active noise control module and noise data access module.

  14. Effect of heparin on prevention of flap loss in microsurgical free flap transfer: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Xuan-Liang Pan

    Full Text Available The effectiveness of heparin for thromboprophylaxis during microvascular free flap transfer is uncertain. The purpose of this meta-analysis was to determine the effect of heparin on the prevention of flap loss in microsurgical free flap transfer.A search of PubMed, Cochrane databases, and Google Scholar using combinations of the search terms heparin, free flap, flap loss, free tissue transfer was conducted on March 15, 2013. Inclusion criteria were: 1 Prospective randomized trials. 2 Retrospective, non-randomized studies. 3 Patients received free tissue transfer. Flap loss rate was used to evaluate treatment efficacy. Odds ratios (ORs with 95% confidence intervals (CI were calculated and compared between therapies. Four studies meet the criteria for analysis and were included. Two studiescompared aspirin and heparin, and the ORs of the 2 studies were 1.688 and 2.087. The combined OR of 2.003 (95% CI 0.976-4.109, p = 0.058 did not indicate any significant difference between heparin and aspirin therapies. Two studiescompared high and low doses of dalteparin/heparin therapies, and the ORs of the 2 studies were 4.691 and 11.00. The combined OR of 7.810 (95% CI 1.859-32.808, p = 0.005 revealed a significant difference indicating that high dose dalteparin or heparin therapy is associated with a greater flap loss rate than low dose therapy. Heparin and aspirin prophylaxis are associated with similar flap loss rates after free flap transfer, and high dose dalteparin or heparin therapy is associated with a greater flap loss rate than low dose therapy.

  15. Indirect control of a single-phase active power filter

    Directory of Open Access Journals (Sweden)

    Mihai CULEA

    2006-12-01

    Full Text Available The control of shunt active power filters using PWM inverters consists in generating a reference by separating, using different methods, the harmonics to be eliminated. The methods used are time-consuming and need dedicated control and signal processing equipments. To avoid these setbacks a new method is proposed in the paper. The active power filter is a current PWM rectifier with voltage output and with a capacitor on the DC side. The PWM rectifier is controlled so that the sum of its current and the load’s current is a sinusoid. The control block as well as simulation results are presented.

  16. Development of Active Noise Control System for Quieting Transformer Noise

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok Kyu; Song, Seik Young; Choi, Huo Yul [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Yun, Dae Hea; Lee, Hyuk Jae [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)

    1997-12-31

    The passive noise control technique made use of sound-absorbing or soundproofing materials, so it required a large area and high cost for installation and had a drawback of poor performance at low frequency. Compared to this, the Active Noise Control attenuates noise sound pressure by using secondary source which has same performance ay low-frequency. Furthermore, it is able to save space and expenses. - research on adaptive algorithms - evaluation of global attenuation of the control - computer simulation - real-time Active Noise Control System Hardware Implementation - ANC system setting in the noisy area.

  17. A study of a three-dimensional self-propelled flying bird with flapping wings

    Science.gov (United States)

    Zhu, LinLin; Guan, Hui; Wu, ChuiJie

    2015-09-01

    In this paper, a study of a three-dimensional (3D) self-propelled bionic flying bird in a viscous flow is carried out. This bionic bird is propelled and lifted through flapping and rotating wings, and better flying can be achieved by adjusting the flapping and rotation motion of wings. In this study, we found that the bird can fly faster forward and upward with appropriate center of rotation and oscillation without more energy consumption and have perfect flight performance at a certain angle of attack by adjusting the center of oscillation. The study utilizes a 3D computational fluid dynamics package which constitutes combined immersed boundary method and the volume of fluid method. In addition, it includes adaptive multigrid finite volume method and control strategy of swimming and flying.

  18. Development of hydraulic brake actuator for active brake control; Active brake seigyoyo yuatsu booster no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Konishi, Y.; Hattori, M. Sugisawa, M.; Nishii, M. [Aisin Seiki Co. Ltd., Aichi (Japan)

    1997-10-01

    Recently, application of active brake control systems of the vehicle are increasing. (Vehicle stability control, Panic brake assist ) We have developed a new hydraulic brake actuator for active brake control systems. New hydraulic brake actuator is composed of the three parts. (Hydraulic booster unit, Power supply unit, Control valve unit) This report describes the construction of the new hydraulic booster unit. 2 refs., 10 figs.

  19. AN ANALYTIC APPROACH TO THEORETICAL MODELING OF HIGHLY UNSTEADY VISCOUS FLOW EXCITED BY WING FLAPPING IN SMALL INSECTS

    Institute of Scientific and Technical Information of China (English)

    余永亮; 童秉纲; 马晖扬

    2003-01-01

    Numerous studies on the aerodynamics of insect wing flapping were carried out on different approaches of flight investigations, model experiments, and numerical simulations, but the theoretical modeling remains to be explored. In the present paper, an analytic approach is presented to model the flow interactions of wing flapping in air for small insects with the surrounding flow fields being highly unsteady and highly viscous. The model of wing flapping is a 2-D flat plate, which makes plunging and pitching oscillations as well as quick rotations reversing its positions of leading and trailing edges, respectively, during stroke reversals. It contains three simplified aerodynamic assumptions:(i) unsteady potential flow; (ii) discrete vortices shed from both leading and trailing edges of the wing; (iii) Kutta conditions applied at both edges. Then the problem is reduced to the solution of the unsteady Laplace equation, by using distributed singularities, i.e., sources/sinks, and vortices in the field. To validate the present physical model and analytic method proposed via benchmark examples, two elemental motions in wing flapping and a case of whole flapping cycles are analyzed,and the predicted results agree well with available experimental and numerical data. This verifies that the present analytical approach may give qualitatively correct and quantitatively reasonable results.Furthermore, the total fluid-dynamic force in the present method can be decomposed into three parts:one due to the added inertial (or mass) effect, the other and the third due to the induction of vortices shed from the leading- and the trailing-edge and their images respectively, and this helps to reveal the flow control mechanisms in insect wing flapping.

  20. Recent results on structural control of an active precision structure

    Science.gov (United States)

    Chu, C. C.; Fanson, J. L.; Smith, R. S.

    1991-01-01

    This paper describes recent results in structural control of an active precision truss structure at JPL. The goal is to develop practical control methodology and to apply to active truss structures intended for high precision space-based optics applications. The active structure considered incorporates piezoelectric active members which apply control forces internal to the structure and thereby improve the structure's dimensional stability. Two approaches to structural control system design were investigated. The first approach uses only noncollocated measurements of acceleration at the location of a simulated optical component to achieve structural stabilization. The second approach is essentially the same as the first one except that a viscous damper was used in place of a truss member on the structure to improve the dampings of selected flexible modes. The corresponding experimental closed-loop results are presented in this paper.

  1. Versatility of the buccinator myomucosal flap in atypical palate reconstructions.

    Science.gov (United States)

    Franco, Diogo; Rocha, Diógenes; Arnaut, Marcio; Freitas, Renato; Alonso, Nivaldo

    2014-10-01

    Initially described for the treatment of cleft palate, the anatomical bases of the buccinator myomucosal flap were described by Bozola et al. (1989). A meticulous search found several reports of its use for the correction of post-palatoplasty oronasal fistulas, with only a few reports of its use for other palate-related pathologies. A retrospective analysis was undertaken of patients treated by the Plastic Surgery Units at the Rio de Janeiro Federal University Hospital (HU-UFRJ) and the São Paulo University Hospital (HC-USP), suffering from palatal lesions not associated with a cleft palate and treated through the use of buccinator myomucosal flaps. The average age was 47 years, with 70% of the patients being male. Assorted aetiologies were noted for palatal defects. When there was significant damage to the soft palate, a superior base pharyngeal flap was used. Of this total, in 71% of the cases only the buccinator myomucosal flap was used. In all cases, the flaps were unilateral, adequately covering the defects in question. The buccinator myomucosal flap is a good option for reconstructing medium to large palate defects, as it is a flap with good vascularization and dimension, in addition to an ample arc of rotation, with primary closure of the donor site, without adding significant morbidity.

  2. Perception Neural Networks for Active Noise Control Systems

    Directory of Open Access Journals (Sweden)

    Wang Xiaoli

    2012-11-01

    Full Text Available In a response to a growing demand for environments of 70dB or less noise levels, many industrial sectors have focused with some form of noise control system. Active noise control (ANC has proven to be the most effective technology. This paper mainly investigates application of neural network on self-adaptation system in active noise control (ANC. An active silencing control system is made which adopts a motional feedback loudspeaker as not a noise controlling source but a detecting sensor. The working fundamentals and the characteristics of the motional feedback loudspeaker are analyzed in detail. By analyzing each acoustical path, identification based adaptive linear neural network is built. This kind of identifying method can be achieved conveniently. The estimated result of each sound channel matches well with its real sound character, respectively.

  3. Buccinator-based myomucosal flaps in intraoral reconstruction: A review and new classification

    OpenAIRE

    Rahpeyma, Amin; Khajehahmadi, Saeedeh

    2013-01-01

    The buccinator-based myomucosal flaps are axial pattern flaps that are suitable in reconstruction of medium sized oral soft tissue defects; they are rich in blood supply, have appropriate thickness and considerable mucosal paddle, and they can secrete saliva. The present study describes surgical anatomy and blood supply of these flaps and demonstrates all possible modifications of these flaps (9 modifications). Many terms (> 10) have been used to refer to buccinator-based myomucosal flaps in ...

  4. Sequential and Multistep Substrate Interrogation Provides the Scaffold for Specificity in Human Flap Endonuclease 1

    KAUST Repository

    Sobhy, M.

    2013-06-06

    Human flap endonuclease 1 (FEN1), one of the structure-specific 5\\' nucleases, is integral in replication, repair, and recombination of cellular DNA. The 5\\' nucleases share significant unifying features yet cleave diverse substrates at similar positions relative to 5\\' end junctions. Using single-molecule Förster resonance energy transfer, we find a multistep mechanism that verifies all substrate features before inducing the intermediary-DNA bending step that is believed to unify 5\\' nuclease mechanisms. This is achieved by coordinating threading of the 5\\' flap of a nick junction into the conserved capped-helical gateway, overseeing the active site, and bending by binding at the base of the junction. We propose that this sequential and multistep substrate recognition process allows different 5\\' nucleases to recognize different substrates and restrict the induction of DNA bending to the last common step. Such mechanisms would also ensure the protection ofDNA junctions from nonspecific bending and cleavage. 2013 The Authors.

  5. Vector disparity sensor with vergence control for active vision systems

    OpenAIRE

    Eduardo Ros; Francisco Barranco; Javier Diaz; Sabatini, Silvio P; Agostino Gibaldi

    2012-01-01

    This paper presents an architecture for computing vector disparity for active vision systems as used on robotics applications. The control of the vergence angle of a binocular system allows us to efficiently explore dynamic environments, but requires a generalization of the disparity computation with respect to a static camera setup, where the disparity is strictly 1-D after the image rectification. The interaction between vision and motor control allows us to develop an active sensor that ac...

  6. Active Inference, homeostatic regulation and adaptive behavioural control

    OpenAIRE

    Pezzulo, G; Rigoli, F.; Friston, K.

    2015-01-01

    We review a theory of homeostatic regulation and adaptive behavioural control within the Active Inference framework. Our aim is to connect two research streams that are usually considered independently; namely, Active Inference and associative learning theories of animal behaviour. The former uses a probabilistic (Bayesian) formulation of perception and action, while the latter calls on multiple (Pavlovian, habitual, goal-directed) processes for homeostatic and behavioural control. We offer a...

  7. Controlling neural activity in Caenorhabditis elegans to evoke chemotactic behavior

    Science.gov (United States)

    Kocabas, Askin; Shen, Ching-Han; Guo, Zengcai V.; Ramanathan, Sharad

    2013-03-01

    Animals locate and track chemoattractive gradients in the environment to find food. With its simple nervous system, Caenorhabditis elegans is a good model system in which to understand how the dynamics of neural activity control this search behavior. To understand how the activity in its interneurons coordinate different motor programs to lead the animal to food, here we used optogenetics and new optical tools to manipulate neural activity directly in freely moving animals to evoke chemotactic behavior. By deducing the classes of activity patterns triggered during chemotaxis and exciting individual neurons with these patterns, we identified interneurons that control the essential locomotory programs for this behavior. Notably, we discovered that controlling the dynamics of activity in just one interneuron pair was sufficient to force the animal to locate, turn towards and track virtual light gradients.

  8. Innovation in Active Vibration Control Strategy of Intelligent Structures

    Directory of Open Access Journals (Sweden)

    A. Moutsopoulou

    2014-01-01

    Full Text Available Large amplitudes and attenuating vibration periods result in fatigue, instability, and poor structural performance. In light of past approaches in this field, this paper intends to discuss some innovative approaches in vibration control of intelligent structures, particularly in the case of structures with embedded piezoelectric materials. Control strategies are presented, such as the linear quadratic control theory, as well as more advanced theories, such as robust control theory. The paper presents sufficiently a recognizable advance in knowledge of active vibration control in intelligent structures.

  9. Active Engine Mounting Control Algorithm Using Neural Network

    Directory of Open Access Journals (Sweden)

    Fadly Jashi Darsivan

    2009-01-01

    Full Text Available This paper proposes the application of neural network as a controller to isolate engine vibration in an active engine mounting system. It has been shown that the NARMA-L2 neurocontroller has the ability to reject disturbances from a plant. The disturbance is assumed to be both impulse and sinusoidal disturbances that are induced by the engine. The performance of the neural network controller is compared with conventional PD and PID controllers tuned using Ziegler-Nichols. From the result simulated the neural network controller has shown better ability to isolate the engine vibration than the conventional controllers.

  10. AN ANATOMIC STUDY OF ADIPOFASCIAL FLAP OF THE LEG

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To investigate the vascular anatomy of the subcutaneous tissues and fascias of the leg. Methods Four fresh cadaver legs which had been injected with colored latex were dissected under magnification to identify the origin, course an distribution of vessels from the subfascial level to the skin. The adipofascial flap was harvested from the whole medial side of the leg and fascial flap from other leg of the same cadaver. The posterior tibial artery and its first and second supra-malleolus septal arteries were retained in these flaps. Selective injection of China ink through posterior tibial artery was carried out, and dimension of ink- stained areas was recorded. Results Three main trunk vessels of the leg gave off branches to deep fascia and subcutaneous tissues, forming a large vascular plexus in the subcutaneous tissues on the deep fascia and a deli- cate, but dense and well anastomosed vascular plexus beneath the deep fascia. The vascular plexus in the subcu- taneous tissues ran deeper than the superficial venous system. The areas stained by selective injection in adipo- fascial flaps were larger than those in the fascial flaps. Conclusion Subcutaneous tissues and deep fascia can be considered as an anatomic entity nourished by two very well developed vascular networks which lie on both sides of deep fascia. Incorporation of the deep fascia can not only protect the subcutaneous tissue from being lacerated during raising of the flap, but also enhance vascularity of the adipofascial flap. Leaving superficial veins intact while raising the skin flap does not jeopardize the vascular plexus in the subcutaneous tissues and can preserve the superficial lymnphatic vessels, so that postoperative edema of the flap or the leg could be avoided.

  11. Vascular Endothelium Growth Factor, Surgical Delay, and Skin Flap Survival

    Science.gov (United States)

    Lineaweaver, William C.; Lei, Man-Ping; Mustain, William; Oswald, Tanya M.; Cui, Dongmei; Zhang, Feng

    2004-01-01

    Objective: Cytokines may be a mechanism by which surgical delay can increase flap survival. We previously found that preoperative vascular endothelium growth factor (VEGF) administration in the rat transverse rectus abdominis myocutaneous (TRAM) flap could improve skin paddle survival. In this study, we used partial elevation of the rat TRAM flap as a surgical delay to assess endogenous cytokine expression and tissue survival comparable to undelayed TRAM flaps. Methods: In Part I, TRAM flaps underwent surgical delay procedures; 7 days later, the flaps were completely elevated and reinset. At the same time, other flaps were raised and reinset without delay. Skin paddle survival in both groups was evaluated at 7 days. In Part II, skin biopsies from TRAM zones I to IV were taken at the time of delay and at intervals of 12, 24, 48, and 72 hours. Specimens were assessed for selected cytokine gene expression by reverse transcription-polymerase chain reaction analysis (TR-PCR). Results: Surgical delay significantly (P < 0.001) increased skin paddle survival in the delayed TRAM flaps (16.14 ± 1.53 cm, 81.9%) compared with undelayed flaps (7.68 ± 3.16 cm, 40.9%). TGF-β and PDGF expressions were not changed by surgical delay, but basic fibroblast growth factor (bFGF) and VEGF expressions increased significantly (P < 0.05 and P < 0.01) after delay. Conclusions: In the rat TRAM model, surgical delay resulted in increased VEGF expression and increased skin paddle survival. These results correlate with previous studies showing the preoperative injection of VEGF increases skin paddle survival. VEGF may be an important element in the delay phenomenon and may be an agent for pharmacological delay. PMID:15166966

  12. Adipofascial Anterolateral Thigh Flap Safety: Applications and Complications

    Directory of Open Access Journals (Sweden)

    Tommaso Agostini

    2013-03-01

    Full Text Available Background A thinned anterolateral thigh (ALT flap is often harvested to achieve optimalskin resurfacing. Several techniques have been described to thin an ALT flap including anadipocutaneous flap, an adipofascial flap and delayed debulking.Methods By systematically reviewing all of the available literature in English and French, thepresent manuscript attempts to identify the common surgical indications, complications anddonor site morbidity of the adipofascial variant of the ALT flap. The studies were identifiedby performing a systematic search on Medline, Ovid, EMBASE, the Cochrane Database ofSystematic Reviews, Current Contents, PubMed, Google, and Google Scholar.Results The study selection process was adapted from the Preferred Reporting Items forSystematic Reviews and Meta-Analyses statement, and 15 articles were identified usingthe study inclusion criteria. These articles were then reviewed for author name(s, year ofpublication, flap dimensions and thickness following defatting, perforator type, type of transfer,complications, thinning technique, number of cases with a particular area of application anddonor site morbidity.Conclusions The adipofascial variant of the ALT flap provides tissue to fill large defects andimprove pliability. Its strong and safe blood supply permits adequate immediate or delayeddebulking without vascular complications. The presence of the deep fascia makes it possibleto prevent sagging by suspending and fixing the flap for functional reconstructive purposes(e.g., the intraoral cavity. Donor site morbidity is minimal, and thigh deformities can bereduced through immediate direct closure or liposuction and direct closure. A safe bloodsupply was confirmed by the rate of secondary flap debulking.

  13. Modeling and Control of Active Suspensions for MDOF Vehicle

    Institute of Scientific and Technical Information of China (English)

    李克强; 郑四发; 杨殿阁; 连小珉; 永井正夫

    2003-01-01

    The conventional method for analyzing active suspension control for a vehicle is only to analyze aquarter or half car with a lower order degree-of freedom (DOF) model, but such models do not actually modelpractical applications. Accurate models of a suspension control system require a multi-degree-of-freedom(MDOF) vehicle model with a detailed model of the controller. An MDOF model was developed including theinfluence of factors such as the engine, the seats, and the passengers to describe vehicle motion using areduced order model of the controller designed by using the H∞ control method. The control systemperformance has been investigated by comparing the H∞ controller with a linear quadratic (LQ) controller.

  14. "Active Flux" DTFC-SVM Sensorless Control of IPMSM

    DEFF Research Database (Denmark)

    Boldea, Ion; Codruta Paicu, Mihaela; Gheorghe-Daniel, Andreescu,;

    2009-01-01

    This paper proposes an implementation of a motionsensorless control system in wide speed range based on "active flux" observer, and direct torque and flux control with space vector modulation (DTFC-SVM) for the interior permanent magnet synchronous motor (IPMSM), without signal injection. The...

  15. Active and passive control of zinc phthalocyanine photodynamics

    NARCIS (Netherlands)

    Sharma, D.; Huijser, J.M.; Savolainen, J.; Steen, G.W.; Herek, J.L.

    2013-01-01

    In this work we report on the ultrafast photodynamics of the photosensitizer zinc phthalocyanine (ZnPc) and manipulation thereof. Two approaches are followed: active control via pulse shaping and passive control via strategic manipulation in the periphery of the molecular structure. The objective of

  16. Applications of active adaptive noise control to jet engines

    Science.gov (United States)

    Shoureshi, Rahmat; Brackney, Larry

    1993-01-01

    During phase 2 research on the application of active noise control to jet engines, the development of multiple-input/multiple-output (MIMO) active adaptive noise control algorithms and acoustic/controls models for turbofan engines were considered. Specific goals for this research phase included: (1) implementation of a MIMO adaptive minimum variance active noise controller; and (2) turbofan engine model development. A minimum variance control law for adaptive active noise control has been developed, simulated, and implemented for single-input/single-output (SISO) systems. Since acoustic systems tend to be distributed, multiple sensors, and actuators are more appropriate. As such, the SISO minimum variance controller was extended to the MIMO case. Simulation and experimental results are presented. A state-space model of a simplified gas turbine engine is developed using the bond graph technique. The model retains important system behavior, yet is of low enough order to be useful for controller design. Expansion of the model to include multiple stages and spools is also discussed.

  17. Smart Materials and Active Noise and Vibration Control in Vehicles

    NARCIS (Netherlands)

    Doppenberg, E.J.J.; Berkhoff, A.P.; Overbeek, van M.

    2001-01-01

    The paper presents the results for the reduction of sound radiated from a structure using different control methodologies, and discusses two approaches for active structural acoustic control: the acoustic approach or the vibro-acoustic approach. Integrated actuators in structure material are necessa

  18. Finite element models applied in active structural acoustic control

    NARCIS (Netherlands)

    Oude Nijhuis, Marco H.H.; Boer, de André; Rao, Vittal S.

    2002-01-01

    This paper discusses the modeling of systems for active structural acoustic control. The finite element method is applied to model structures including the dynamics of piezoelectric sensors and actuators. A model reduction technique is presented to make the finite element model suitable for controll

  19. Active Vibration Control of a Monopile Offshore Structure

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.; Kirkegaard, Poul Henning; Thesbjerg, L.

    1999-01-01

    In the Danish part of the North Sea monopile platforms with a cylindrical shaft have been used at the exploitation of marginal fields. In the paper a new principle for active vibration control of such structures is suggested. The principle is based on a control of the boundary layer flow around......, where reductions in the vibration level of up to 50% have been registered....

  20. The flap by flap dissection in terminal ballistic applied to less lethal weapons.

    Science.gov (United States)

    de Freminville, Humbert; Rongieras, Fréderic; Prat, Nicolas; Voiglio, Eric J

    2011-06-01

    Medical examiners often have to solve questions such as firing distance and bullet trajectory for lethal weapons. Knowledge in the field of terminal ballistics has increased during the last 30 years and layer by layer dissection reveals superficial wounds that can be linked with the permanent cavity. At the end of the 1990s, terminal ballistics also focused on less lethal weapons and their wounds. Here, 2 different less lethal weapons with single bullets were tested on nonembalmed and undressed cadavers (N = 26) at different ranges and speeds. We have developed a technique for dissection which we call flap by flap dissection that reveals the advantage of the bullet-skin-bone entity, the absence of wounds linking its components and range of less lethal weapons. PMID:20110799

  1. The infrahyoid flap: a comprehensive review of an often overlooked reconstructive method.

    Science.gov (United States)

    Deganello, Alberto; Leemans, C René

    2014-08-01

    The infrahyoid flap is a myocutaneous pedicled flap mainly nourished by the superior thyroid vessels through the perforators of the infrahyoid muscles. This thin and pliable flap provides a skin island of about 7 by 4 cm from the central part of the anterior neck. The flap can be transferred on its pedicle of superior thyroid artery and vein to reconstruct medium sized head and neck defects created after cancer ablation. We have successfully used this flap in a series of 40 cases with no total flap loss and with 1 case of superficial skin necrosis. The aim of this review is to highlight the clinical usefulness of this pedicled flap even in the microvascular free flap era. A comprehensive review of the available literature reporting on the infrahyoid flap has been carried out using a web search. The history of the infrahyoid flap, the surgical technique with technical innovations, the clinical utility and limitations of this flap, are reported and discussed. Among the 7 larger series (cohort larger than 50 cases) a total of 956 flaps were performed, and the global success rate was 91.7%, with failures being mainly related to partial skin necrosis, as the rate of total (skin and muscle) flap necrosis was only 1%. This flap is reliable, easy to harvest during neck dissection, oncologically safe, it does carry a negligible donor site morbidity. This paper highlights how the infrahyoid flap can represent an excellent reconstructive solution in selected patients and head and neck sites. PMID:24856306

  2. Tolerance of gastric mucosal flap to postoperative irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Devineni, V.R.; Hayden, R.; Fredrickson, J.; Sicard, G. (Washington Univ. Medical Center, St. Louis, MO (USA))

    1991-05-01

    When malignant lesions of the oral cavity, base of tongue, and oropharynx are treated with radical resection, adequate reconstruction is required. The free gastric mucosal flap with microvascular transfer is being used with increasing frequency at Washington University Medical Center. Because of the advanced nature of the primary lesions, most patients also require postoperative radiation therapy. In this paper the tolerance of the gastric mucosal flap to postoperative radiation therapy is reviewed. The changes resulting from radiation therapy in the mucosal flap were found to be acceptable, and no major complications were encountered.

  3. Management of a Traumatic Flap Dislocation Seven Years after LASIK

    Directory of Open Access Journals (Sweden)

    Majid Moshirfar

    2011-01-01

    Full Text Available Seven years after uneventful laser in situ keratomileusis (LASIK, a 48-year-old woman presented one week after being hit with an iron cord with blurry vision, pain, and irritation. The injury resulted in traumatic flap dislocation, epithelial ingrowth, and macrostriae. Following epithelial removal, the flap was refloated and repositioned. Nine interrupted sutures were used to secure the flap. Three-weeks after surgery with no sutures remaining, the epithelial ingrowth and macrostriae had resolved with a visual acuity of 20/20.

  4. Passive and Active Vibration Control of Renewable Energy Structures

    OpenAIRE

    Zhang, Zili

    2015-01-01

    The present thesis deals with fundamental researches on passive and active vibration control of renewable energy structures, and provides useful models for practical applications. Effective and robust vibration control methods have been explored for mitigating the lightly damped edgewise blade vibration and lateral tower vibration, with the main focus on structural control devices. Rigorous theoretical modeling of different dynamic system has been established, based on which detailed design a...

  5. Active vibration control techniques for flexible space structures

    Science.gov (United States)

    Parlos, Alexander G.; Jayasuriya, Suhada

    1990-01-01

    Two proposed control system design techniques for active vibration control in flexible space structures are detailed. Control issues relevant only to flexible-body dynamics are addressed, whereas no attempt was made to integrate the flexible and rigid-body spacecraft dynamics. Both of the proposed approaches revealed encouraging results; however, further investigation of the interaction of the flexible and rigid-body dynamics is warranted.

  6. Improving active space telescope wavefront control using predictive thermal modeling

    Science.gov (United States)

    Gersh-Range, Jessica; Perrin, Marshall D.

    2015-01-01

    Active control algorithms for space telescopes are less mature than those for large ground telescopes due to differences in the wavefront control problems. Active wavefront control for space telescopes at L2, such as the James Webb Space Telescope (JWST), requires weighing control costs against the benefits of correcting wavefront perturbations that are a predictable byproduct of the observing schedule, which is known and determined in advance. To improve the control algorithms for these telescopes, we have developed a model that calculates the temperature and wavefront evolution during a hypothetical mission, assuming the dominant wavefront perturbations are due to changes in the spacecraft attitude with respect to the sun. Using this model, we show that the wavefront can be controlled passively by introducing scheduling constraints that limit the allowable attitudes for an observation based on the observation duration and the mean telescope temperature. We also describe the implementation of a predictive controller designed to prevent the wavefront error (WFE) from exceeding a desired threshold. This controller outperforms simpler algorithms even with substantial model error, achieving a lower WFE without requiring significantly more corrections. Consequently, predictive wavefront control based on known spacecraft attitude plans is a promising approach for JWST and other future active space observatories.

  7. UML activity diagram swimlanes in logic controller design

    Science.gov (United States)

    Grobelny, Michał; Grobelna, Iwona

    2015-12-01

    Logic controller behavior can be specified using various techniques, including UML activity diagrams and control Petri nets. Each technique has its advantages and disadvantages. Application of both specification types in one project allows to take benefits from both of them. Additional elements of UML models make it possible to divide a specification into some parts, considered from other point of view (logic controller, user or system). The paper introduces an idea to use UML activity diagrams with swimlanes to increase the understandability of design models.

  8. Remote Control of T Cell Activation Using Magnetic Janus Particles.

    Science.gov (United States)

    Lee, Kwahun; Yi, Yi; Yu, Yan

    2016-06-20

    We report a strategy for using magnetic Janus microparticles to control the stimulation of T cell signaling with single-cell precision. To achieve this, we designed Janus particles that are magnetically responsive on one hemisphere and stimulatory to T cells on the other side. By manipulating the rotation and locomotion of Janus particles under an external magnetic field, we could control the orientation of the particle-cell recognition and thereby the initiation of T cell activation. This study demonstrates a step towards employing anisotropic material properties of Janus particles to control single-cell activities without the need of complex magnetic manipulation devices.

  9. Impact of active controls technology on structural integrity

    Science.gov (United States)

    Noll, Thomas; Austin, Edward; Donley, Shawn; Graham, George; Harris, Terry

    1991-01-01

    This paper summarizes the findings of The Technical Cooperation Program to assess the impact of active controls technology on the structural integrity of aeronautical vehicles and to evaluate the present state-of-the-art for predicting the loads caused by a flight-control system modification and the resulting change in the fatigue life of the flight vehicle. The potential for active controls to adversely affect structural integrity is described, and load predictions obtained using two state-of-the-art analytical methods are given.

  10. Active Noise Control Experiments using Sound Energy Flu

    Science.gov (United States)

    Krause, Uli

    2015-03-01

    This paper reports on the latest results concerning the active noise control approach using net flow of acoustic energy. The test set-up consists of two loudspeakers simulating the engine noise and two smaller loudspeakers which belong to the active noise system. The system is completed by two acceleration sensors and one microphone per loudspeaker. The microphones are located in the near sound field of the loudspeakers. The control algorithm including the update equation of the feed-forward controller is introduced. Numerical simulations are performed with a comparison to a state of the art method minimising the radiated sound power. The proposed approach is experimentally validated.

  11. Robust Vehicle Suspension System by Converting Active & Passive Control of a Vehicle to Semi-Active Control System Analytically

    Directory of Open Access Journals (Sweden)

    Hassan Elahi

    2014-12-01

    Full Text Available In this research work a simplified translational model of an automotive suspension system is constructed by only considering the translation motion of one wheel of a car. Passive Vehicle Suspension System is converted into Semi Active Vehicle System. Major advantage achieved by this system is that it adjusts the damping of the suspension system without the application of any actuator by using MATLAB® simulations. The semi-active control is found to control the vibration of suspension system very well.

  12. Robust Vehicle Suspension System by Converting Active & Passive Control of a Vehicle to Semi-Active Control System Analytically

    OpenAIRE

    Hassan Elahi; Dr. Riffat Asim Pasha; Dr. Asif Israr; Dr. M. Zubair Khan

    2014-01-01

    In this research work a simplified translational model of an automotive suspension system is constructed by only considering the translation motion of one wheel of a car. Passive Vehicle Suspension System is converted into Semi Active Vehicle System. Major advantage achieved by this system is that it adjusts the damping of the suspension system without the application of any actuator by using MATLAB® simulations. The semi-active control is found to control the vibration of suspens...

  13. Active structural control by fuzzy logic rules: An introduction

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Y.

    1995-07-01

    An introduction to fuzzy logic control applied to the active structural control to reduce the dynamic response of structures subjected to earthquake excitations is presented. It is hoped that this presentation will increase the attractiveness of the methodology to structural engineers in research as well as in practice. The basic concept of the fuzzy logic control are explained by examples and by diagrams with a minimum of mathematics. The effectiveness and simplicity of the fuzzy logic control is demonstrated by a numerical example in which the response of a single-degree-of-freedom system subjected to earthquake excitations is controlled by making use of the fuzzy logic controller. In the example, the fuzzy rules are first learned from the results obtained from linear control theory; then they are fine tuned to improve their performance. It is shown that the performance of fuzzy logic control surpasses that of the linear control theory. The paper shows that linear control theory provides experience for fuzzy logic control, and fuzzy logic control can provide better performance; therefore, two controllers complement each other.

  14. Active structural control by fuzzy logic rules: An introduction

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yu [Argonne National Lab., IL (United States). Reactor Engineering Div.; Wu, Kung C. [Texas Univ., El Paso, TX (United States). Dept. of Mechanical and Industrial Engineering

    1996-12-31

    A zeroth level introduction to fuzzy logic control applied to the active structural control to reduce the dynamic response of structures subjected to earthquake excitations is presented. It is hoped that this presentation will increase the attractiveness of the methodology to structural engineers in research as well as in practice. The basic concept of the fuzzy logic control are explained by examples and by diagrams with a minimum of mathematics. The effectiveness and simplicity of the fuzzy logic control is demonstrated by a numerical example in which the response of a single- degree-of-freedom system subjected to earthquake excitations is controlled by making use of the fuzzy logic controller. In the example, the fuzzy rules are first learned from the results obtained from linear control theory; then they are fine tuned to improve their performance. It is shown that the performance of fuzzy logic control surpasses that of the linear control theory. The paper shows that linear control theory provides experience for fuzzy logic control, and fuzzy logic control can provide better performance; therefore, two controllers complement each other.

  15. Neural Network-Based Active Control for Offshore Platforms

    Institute of Scientific and Technical Information of China (English)

    周亚军; 赵德有

    2003-01-01

    A new active control scheme, based on neural network, for the suppression of oscillation in multiple-degree-of-freedom (MDOF) offshore platforms, is studied in this paper. With the main advantages of neural network, i.e. the inherent robustness, fault tolerance, and generalized capability of its parallel massive interconnection structure, the active structural control of offshore platforms under random waves is accomplished by use of the BP neural network model. The neural network is trained offline with the data generated from numerical analysis, and it simulates the process of Classical Linear Quadratic Regular Control for the platform under random waves. After the learning phase, the trained network has learned about the nonlinear dynamic behavior of the active control system, and is capable of predicting the active control forces of the next time steps. The results obtained show that the active control is feasible and effective, and it finally overcomes time delay owing to the robustness, fault tolerance, and generalized capability of artificial neural network.

  16. Active inference and robot control: a case study

    Science.gov (United States)

    Nizard, Ange; Friston, Karl; Pezzulo, Giovanni

    2016-01-01

    Active inference is a general framework for perception and action that is gaining prominence in computational and systems neuroscience but is less known outside these fields. Here, we discuss a proof-of-principle implementation of the active inference scheme for the control or the 7-DoF arm of a (simulated) PR2 robot. By manipulating visual and proprioceptive noise levels, we show under which conditions robot control under the active inference scheme is accurate. Besides accurate control, our analysis of the internal system dynamics (e.g. the dynamics of the hidden states that are inferred during the inference) sheds light on key aspects of the framework such as the quintessentially multimodal nature of control and the differential roles of proprioception and vision. In the discussion, we consider the potential importance of being able to implement active inference in robots. In particular, we briefly review the opportunities for modelling psychophysiological phenomena such as sensory attenuation and related failures of gain control, of the sort seen in Parkinson's disease. We also consider the fundamental difference between active inference and optimal control formulations, showing that in the former the heavy lifting shifts from solving a dynamical inverse problem to creating deep forward or generative models with dynamics, whose attracting sets prescribe desired behaviours. PMID:27683002

  17. 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

    more practical control strategy appears to be to minimise the weighted sum of squared forces and velocities below the mounts, which gives near-optimal performance in simulations. These theoretical results are supported by experiments with a real-time control system. The actuator and sensor requirements...... 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...

  18. CT-guided deep inferior epigastric perforator (DIEP) flap localization — Better for the patient, the surgeon, and the hospital

    International Nuclear Information System (INIS)

    Aims: To define the clinical benefits to the patient of preoperative imaging planning for deep inferior epigastric perforator (DIEP) flap reconstruction. Materials and methods: Since 2009 computed tomography angiography (CTA) has been provided for the preoperative planning of DIEP flap breast reconstruction in the largest plastic surgery unit in southeast England. In a retrospective, cohort–control study the outcomes of 100 consecutive patients who underwent preoperative CTA planning were compared with a closely-matched control group who underwent ultrasound planning only. The cohorts were evaluated for operative duration, mean operative blood loss and transfusion requirement, morbidity and flap or donor-site complications. Results: There were statistically significant improvements in mean operative duration (p < 0.05), intra-operative blood loss (p < 0.05), shorter mean inpatient stay (p < 0.05) for the CTA planning versus the ultrasound planning of DIEP flap reconstruction. Conclusion: Statistically significant benefits were demonstrated in key aspects of the surgical procedure following CTA-guided planning. The implications of these benefits are profound in terms of pure healthcare cost benefits.

  19. Reconstruction of Abdominal Wall of a Chronically Infected Postoperative Wound with a Rectus Abdominis Myofascial Splitting Flap

    Directory of Open Access Journals (Sweden)

    Sung Kyu Bae

    2013-01-01

    Full Text Available Background If a chronically infected abdominal wound develops, complications such asperitonitis and an abdominal wall defect could occur. This could prolong the patient’s hospitalstay and increase the possibility of re-operation or another infection as well. For this reason,a solution for infection control is necessary. In this study, surgery using a rectus abdominismuscle myofascial splitting flap was performed on an abdominal wall defect.Methods From 2009 to 2012, 5 patients who underwent surgery due to ovarian rupture,cesarean section, or uterine myoma were chosen. In each case, during the first week afteroperation, the wound showed signs of infection. Surgery was chosen because the wounds didnot resolve with dressing. Debridement was performed along the previous operation woundand dissection of the skin was performed to separate the skin and subcutaneous tissue fromthe attenuated rectus muscle and Scarpa’s fascial layers. Once the anterior rectus sheath andmuscle were adequately mobilized, the fascia and muscle flap were advanced medially sothat the skin defect could be covered for reconstruction.Results Upon 3-week follow-up after a rectus abdominis myofascial splitting flap operation,no major complication occurred. In addition, all of the patients showed satisfaction in termsof function and esthetics at 3 to 6 months post-surgery.Conclusions Using a rectus abdominis myofascial splitting flap has many esthetic andfunctional benefits over previous methods of abdominal defect treatment, and notably, itenabled infection control by reconstruction using muscle.

  20. Active vibration control using state space LQG and internal model control methods

    DEFF Research Database (Denmark)

    Mørkholt, Jakob; Elliott, S.J.

    1998-01-01

    Two ways of designing discrete time robust H2-controllers for feedback broadband active vibration control are compared through computer simulations. The methods are based on different models of disturbance and plant transfer functions, but yield controllers with identical properties. Two simple...... ways of introducing robustness into the H2-design are compared, and finally an efficient way of designing a practical IIR-controller is proposed....