WorldWideScience

Sample records for pylons

  1. Active Aircraft Pylon Noise Control System

    Science.gov (United States)

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

    2017-01-01

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

  2. Research on dynamic characteristics model test scheme for middle pylon of multi-pylon multi-span suspension bridges

    Institute of Scientific and Technical Information of China (English)

    Zhang Yufeng; Zhang Dachang

    2012-01-01

    Multi-pylon multi-span suspension bridge is a new type super flexible structure system, and the rigidity design of middle pylon is one of the main difficult technical issues. Due to the requirements of longitudinal rigidity, the structural form and the corresponding foundation type of middle pylon are different from those of the ordinary steel pylon, and the complicated dynamic characteristics make the calculation quite difficult. In this article, exploration has been made in selection of similarity ratio and model materials, section simulation, restriction conditions simulation, fixing of mass blocks, fabrication scheme and testing method by taking into account different construction and working conditions such as restriction conditions and working environment of a three-pylon suspension bridge, to conduct the test experimental design of the dynamic behavior of the middle pylon, with the purpose to reveal its dynamic characteristics and make comparison and analysis with theoretical assumptions, to provide basis for anti-wind and anti-seismic design and reference for the design and research of three-pylon two-span suspension bridges in the future.

  3. Remote pivot decoupler pylon: Wing/store flutter suppressor

    Science.gov (United States)

    Hassler, J. M., Jr. (Inventor)

    1986-01-01

    A device for suspending a store from an aerodynamic support surface, such an an aircraft wing, and more specifically, for improving upon singlet pivot decoupler pylons by reducing both frequency of active store, alignment, and alignment system space and power requirements. Two links suspend a lower pylon/rack section and releasable attached store from an upper pylon section mounted under the wing. The links allow the lower pylon section to rotate in pitch about a remote pivot point. A leaf spring connected between the lower section and electrical alignment system servomechanism provides pitch alignment of the lower section/store combination. The servomechanism utilizes an electric servomotor to drive the gear train and reversibly move the leaf spring, thereby maintaining the pitch attitude of the store within acceptable limits. The damper strokes when the lower section rotates to damp large oscillations of store.

  4. Wing/store flutter with nonlinear pylon stiffness

    Science.gov (United States)

    Desmarais, R. N.; Reed, W. H., III

    1980-01-01

    Recent wind tunnel tests and analytical studies show that a store mounted on a pylon with soft pitch stiffness provides substantial increase in flutter speed of fighter aircraft and reduces dependency of flutter on mass and inertia of the store. This concept, termed the decoupler pylon, utilizes a low frequency control system to maintain pitch alignment of the store during maneuvers and changing flight conditions. Under rapidly changing transient loads, however, the alignment control system may allow the store to momentarily bottom against a relatively stiff backup structure in which case the pylon stiffness acts as a hardening nonlinear spring. Such structural nonlinearities are known to affect not only the flutter speed but also the basic behavior of the instability. The influence of pylon stiffness nonlinearities or the flutter characteristics of wing mounted external stores is examined.

  5. Experimental study of mixing enhancement using pylon in supersonic flow

    Science.gov (United States)

    Vishwakarma, Manmohan; Vaidyanathan, Aravind

    2016-01-01

    The Supersonic Combustion Ramjet (SCRAMJET) engine has been recognized as one of the most promising air breathing propulsion system for the supersonic/hypersonic flight mission requirements. Mixing and combustion of fuel inside scramjet engine is one of the major challenging tasks. In the current study the main focus has been to increase the penetration and mixing of the secondary jet inside the test chamber at supersonic speeds. In view of this, experiments are conducted to evaluate the effect of pylon on the mixing of secondary jet injection into supersonic mainstream flow at Mach 1.65. Two different pylons are investigated and the results are compared with those obtained by normal injection from a flat plate. The mixing studies are performed by varying the height of the pylon while keeping all other parameters the same. The study mainly focused on analyzing the area of spread and penetration depth achieved by different injection schemes based on the respective parameters. The measurements involved Mie scattering visualization and the flow features are analyzed using Schlieren images. The penetration height and spread area are the two parameters that are used for analyzing and comparing the performance of the pylons. It is observed that the secondary jet injection carried out from behind the big pylon resulted in maximum penetration and spread area of the jet as compared to the small pylon geometry. Moreover it is also evident that for obtaining maximum spreading and penetration of the jet, the same needs to be achieved at the injection location.

  6. Variable Geometry Aircraft Pylon Structure and Related Operation Techniques

    Science.gov (United States)

    Shah, Parthiv N. (Inventor)

    2014-01-01

    An aircraft control structure can be utilized for purposes of drag management, noise control, or aircraft flight maneuvering. The control structure includes a high pressure engine nozzle, such as a bypass nozzle or a core nozzle of a turbofan engine. The nozzle exhausts a high pressure fluid stream, which can be swirled using a deployable swirl vane architecture. The control structure also includes a variable geometry pylon configured to be coupled between the nozzle and the aircraft. The variable geometry pylon has a moveable pylon section that can be deployed into a deflected state to maintain or alter a swirling fluid stream (when the swirl vane architecture is deployed) for drag management purposes, or to assist in the performance of aircraft flight maneuvers.

  7. A 174 passenger aircraft pylon design and analysis.

    OpenAIRE

    Marcos Vinicius Pirrho Loureiro

    2006-01-01

    The goal of this work is to verify the pylon design of a 174 passenger aircraft. This aircraft was studied by the fourth class of Embraer's Engineer Specialization Program (PEE 4). The engine of this aircraft is located below the wing and its model is GE CFM-56. The fan size was increased in order to reach a higher air passage ratio. This pylon concept presented here was studied and adopted by the group as the better option for this type of airplane. Due to the short time allowable to this st...

  8. Effect of pylon cross-sectional geometries on propulsion integration for a low-wing transport

    Science.gov (United States)

    Ingraldi, Anthony M.; Naik, Dinesh A.; Pendergraft, Odis C., Jr.

    1993-01-01

    An experimental program was conducted in the Langley 16-Foot Transonic Tunnel to evaluate the performance effects of various types of pylons on a 1/17th-scale, low-wing transport model. The model wing was designed for cruise at a Mach number of 0.77 and a lift coefficient of 0.55. The pylons were tested at two wing semispan locations over a range of toe-in angles. The effects of toe-in angle were found to be minimal, but the variation in geometry had a more pronounced effect on the lift characteristics of the model. A pylon whose maximum thickness occurred at the wing trailing edge, known as a compression pylon, proved to be the best choice in terms of retaining the flow characteristics of the wing without pylons. Practical considerations such as structural viability may necessitate modification of the compression pylon concept in order to take advantage of its apparent benefits.

  9. Comparison of conventional and compression pylon designs for an underwing nacelle

    OpenAIRE

    Devine, Raymond; Cooper, Richard K; Gault, Richard; Watterson, John K.; Bénard, Emmanuel

    2009-01-01

    This paper addresses one of the key components required to produce an environmentally friendly aircraft by reducing drag (and hence fuel consumption) through improved aerodynamic integration of the wing, pylon, and nacelle. The results of a computational investigation comparing the aerodynamic performance of a compression pylon design to a DLR F6 based conventional pylon design are presented in this paper. As with other computational predictions, the total lift and total drag were overpredict...

  10. Computation and comparison of the installation effects of compression pylons for a high wing transport

    Science.gov (United States)

    Chandrasekaran, B.

    1988-01-01

    The three-dimensional transonic Euler method with boundary layer interaction is used to study the flow about a transport aircraft equipped with NASA-developed compression pylons. The results show that the present pylons perform well under the installed conditions, reducing the wing/pylon junction velocities and thus reducing the installed loft loss and drag. The predicted theoretical results are found to agree moderately well with experimental wind tunnel results.

  11. A structural dynamics study of a wing-pylon-tiltrotor system

    Science.gov (United States)

    Khader, N.; Abu-Mallouh, R.

    1992-12-01

    A simple structural model for a three-bladed tiltrotor-pylon-wing assembly is presented, which accounts for chordwise, transverse, and torsional wing deformations, rigid pylon pitching motion with respect to the wing tip cross-section in its deformed position, lead-lag, flap, and torsional deformations of rotor blades. The model considers equivalent viscous damping associated with blade and wing elastic deformations and with rigid pylon pitching motion. It is established that blade-to wing bending rigidity ratio, pylon pitching frequency, equivalent viscous damping associated with blade elastic deformations, and rotational speed, are the most important design parameters, whose effect on system frequencies and stability boundaries is evaluated.

  12. Design and construction of Sutong Bridge deep-water main-pylon foundations

    Institute of Scientific and Technical Information of China (English)

    Ren Huixing; Ouyang Xiaoyong; He Maosheng; Nie Qinlong; Wang Xiali

    2009-01-01

    This paper, from three aspects including construction conditions, foundation design and construction, introduces some considerations in the designing of main-pylon foundations and some practical measures to deal with certain unfavorable construction conditions, such as deep water, tidal effect, soft stratum and heavy traffic, during the construction of main-pylon foundations.

  13. Flight test of a decoupler pylon for wing/store flutter suppression

    Science.gov (United States)

    Cazier, F. W., Jr.; Kehoe, M. W.

    1986-01-01

    The decoupler pylon is a NASA concept of passive wing-store flutter suppression achieved by providing a low store-pylon pitch frequency. Flight tests were performed on an F-16 aircraft carrying on each wing an AIM-9J wingtip missile, a GBU-8 bomb near midspan, and an external fuel tank. Baseline flights with the GBU-8 mounted on a standard pylon established that this configuration is characterized by an antisymmetric limited amplitude flutter oscillation within the operational envelope. The airplane was then flown with the GBU-8 mounted on the decoupler pylon. The decoupler pylon successfully suppressed wing-store flutter throughout the flight envelope. A 37-percent increase in flutter velocity over the standard pylon was demonstrated. Maneuvers with load factors to 4g were performed. Although the static store displacements during maneuvers were not sufficiently large to be of concern, a store pitch alignment system was tested and performed successfully. One GBU-8 was ejected demonstrating that weapon separation from the decoupler pylon is normal. Experience with the present decoupler pylon design indicated that friction in the pivoting mechanism could affect its proper functioning as a flutter suppressor.

  14. Integration effects of pylon geometry on a high-wing transport airplane

    Science.gov (United States)

    Carlson, John R.; Lamb, Milton

    1989-01-01

    An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the installation effects of a series of pylons that had differing cross-sectional shapes on the pressure distributions and aerodynamic characteristics of a 1/24-scale high wing transport. The tests were conducted at Mach numbers at 0.70 and 0.80 at angles of attack from -3 degrees to 4 degrees with the pylons tested at various toe angles between 5 degrees inboard and 5 degrees outboard. Results of this study indicate that the installed drag was lowest for the pylons with a compression pylon type design which kept the flow under the wing in the pylon/wing junction comparable to the clean wing velocities.

  15. Pylon Effects on a Scramjet Cavity Flameholder Flowfield

    Science.gov (United States)

    2008-09-01

    3.5 4.0 4.5 5.0 0 100 200 300 400 500 600 y ( c m ) Streamwise Velocity (m/s) CFD PIV PROBE ANALYTICAL SURF . PRESS. 49 IV. Computational Approach...combination of wind tunnel experimentation and steady-state computational fluid dynamics ( CFD ). Flowfield effects of the pylon-cavity were examined...approximately three times the mass exchange between the cavity and overlying flow. Both CFD and particle image velocimetry data showed strong upward flow

  16. Simulated transonic flows for aircraft with nacelles, pylons, and winglets

    Science.gov (United States)

    Boppe, C. W.; Stern, M. A.

    1980-01-01

    A computational method which simulates transonic flow about wing-fuselage configurations has been extended to include the treatment of multiple body and non-planar wing surfaces. The finite difference relaxation scheme is characterized by a modified small disturbance flow equation and multiple embedded grid system. Wing-body combinations with as many as four nacelles/pods, four pylons, and wing-tip-mounted winglets can be analyzed. A scheme for modeling inlet spillage and engine exhaust interference effects has been included. Computed results are correlated with experimental data for three transport configurations.

  17. Predictions of wing and pylon forces caused by propeller installation

    Science.gov (United States)

    Martinez, Rudolph

    1987-05-01

    Replacement of current turbojets by high-efficiency unducted propfans could have the unfortunate side effect of increasing cabin noise, essentially because unsteady-aerodynamic mechanisms are likely to be introduced whereby some of the energy saved may be lost again, to the production of propeller noise and to wing/pylon vibrations coupling to the cabin as a sounding board. The present study estimates theoretically associated harmonic aerodynamic forces for two candidate configurations: a pusher propeller which chops through the mean wake of the pylon supporting it, and in the process generates a blade-rate force driving the structure, and a tractor wing-mounted propeller, whose trailing rotating wake induces an unsteady downwash field generating unsteady wing airloads. Reported predictions of such propfan aerodynamic sources of structure-borne sound, or vibration, could be the basis for devising means for their mechanical isolation, and thus for the effective interruption of the structural noise path into the cabin. Both mechanisms are analyzed taking advantage of the high subsonic Mach number and high reduced frequency of the interaction between the impinging flow and the affected aerodynamic element.

  18. Construction and alignment control of the middle steel pylon of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Ji Lin; You Xinpeng

    2011-01-01

    The general construction procedure of the steel middle pylon is briefly introduced. The alignment control of the pylon is carried out during the whole process of the construction. The control concept is extended to the manufacture stage. The manufacturing alignment error is strictly controlled in the segments precast process in factory, and the error is recognized and predicted precisely during the installation stage. The adjusting joints are employed to amend the accumulated error, which ensure that the steel pylon alignment could satisfy the precision requirements after installation.

  19. Wind tunnel study on wind-induced vibration of middle pylon of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Ma Rujin; Zhang Zhen; Chen Airong

    2012-01-01

    Full aero-elastic model tests are carried out to investigate wind-induced vibration of middle steel pylon of Taizhou Bridge. Model of the pylon under different construction periods is tested in both uniform and turbulent flow field. And the yaw angle of wind changes from transverse to longitudinal. Through full aero-elastic model testing, windinduced vibration is checked, which includes vortex resonance, buffeting and galloping. Vortex resonance is observed and further studies are carried out by changing damping ratio. Based on wind tunnel testing results, wind-resistance of middle pylon is evaluated and some suggestions are given for middle pylon' s construction.

  20. Assessment of Lateral Driving Stability of Automobiles Passing by the Pylon Zone under Cross Wind

    OpenAIRE

    Dalei Wang; Airong Chen

    2012-01-01

    In order to explore the reason of lateral instability of automobile passing by the pylon zone of cablesupported bridge under cross wind, a new evaluation method of lateral driving stability of automobile considering alternative cross wind is established based on multi-objective driving stability criteria and subjective assessment. Typical driving control process and dynamic response of automobile passing by the pylon zone is given by numerical simulation based on steering wheel fixed-control ...

  1. Nacelle/pylon/wing integration on a transport model with a natural laminar flow nacelle

    Science.gov (United States)

    Lamb, M.; Aabeyounis, W. K.; Patterson, J. C., Jr.

    1985-01-01

    Tests were conducted in the Langley 16-Foot Transonic Tunnel at free-stream Mach numbers from 0.70 to 0.82 and angles of attack from -2.5 deg to 4.0 deg to determine if nacelle/pylon/wing integration affects the achievement of natural laminar flow on a long-duct flow-through nacelle for a high-wing transonic transport configuration. In order to fully assess the integration effect on a nacelle designed to achieve laminar flow, the effects of fixed and free nacelle transitions as well as nacelle longitudinal position and pylon contouring were obtained. The results indicate that the ability to achieve laminar flow on the nacelle is not significantly altered by nacelle/pylon/wing integration. The increment in installed drag between free and fixed transition for the nacelles on symmetrical pylons is essentially the calculated differences between turbulent and laminar flow on the nacelles. The installed drag of the contoured pylon is less than that of the symmetrical pylon. The installed drag for the nacelles in a rearward position is greater than that for the nacelles in a forward position.

  2. Mathematical modeling and mechanical and histopathological testing of porous prosthetic pylon for direct skeletal attachment

    Science.gov (United States)

    Pitkin, Mark; Raykhtsaum, Grigory; Pilling, John; Shukeylo, Yuri; Moxson, Vladimir; Duz, Volodimir; Lewandowski, John; Connolly, Raymond; Kistenberg, Robert S.; Dalton, John F.; Prilutsky, Boris; Jacobson, Stewart

    2010-01-01

    This article presents recent results in the development of the skin and bone integrated pylon (SBIP) intended for direct skeletal attachment of limb prostheses. In our previous studies of the porous SBIP-1 and SBIP-2 prototypes, the bond site between the porous pylons and residuum bone and skin did not show the inflammation characteristically observed when solid pylons are used. At the same time, porosity diminished the strength of the pylon. To find a reasonable balance between the biological conductivity and the strength of the porous pylon, we developed a mathematical model of the composite permeable structure. A novel manufacturing process was implemented, and the new SBIP-3 prototype was tested mechanically. The minimal strength requirements established earlier for the SBIP were exceeded threefold. The first histopathological analysis of skin, bone, and the implanted SBIP-2 pylons was conducted on two rats and one cat. The histopathological analysis provided new evidence of inflammation-free, deep ingrowth of skin and bone cells throughout the SBIP structure. PMID:19675985

  3. A Model-Driven Approach for 3D Modeling of Pylon from Airborne LiDAR Data

    Directory of Open Access Journals (Sweden)

    Qingquan Li

    2015-09-01

    Full Text Available Reconstructing three-dimensional model of the pylon from LiDAR (Light Detection And Ranging point clouds automatically is one of the key techniques for facilities management GIS system of high-voltage nationwide transmission smart grid. This paper presents a model-driven three-dimensional pylon modeling (MD3DM method using airborne LiDAR data. We start with constructing a parametric model of pylon, based on its actual structure and the characteristics of point clouds data. In this model, a pylon is divided into three parts: pylon legs, pylon body and pylon head. The modeling approach mainly consists of four steps. Firstly, point clouds of individual pylon are detected and segmented from massive high-voltage transmission corridor point clouds automatically. Secondly, an individual pylon is divided into three relatively simple parts in order to reconstruct different parts with different strategies. Its position and direction are extracted by contour analysis of the pylon body in this stage. Thirdly, the geometric features of the pylon head are extracted, from which the head type is derived with a SVM (Support Vector Machine classifier. After that, the head is constructed by seeking corresponding model from pre-build model library. Finally, the body is modeled by fitting the point cloud to planes. Experiment results on several point clouds data sets from China Southern high-voltage nationwide transmission grid from Yunnan Province to Guangdong Province show that the proposed approach can achieve the goal of automatic three-dimensional modeling of the pylon effectively.

  4. A Stochastic Geometry Method for Pylon Reconstruction from Airborne LiDAR Data

    Directory of Open Access Journals (Sweden)

    Bo Guo

    2016-03-01

    Full Text Available Object detection and reconstruction from remotely sensed data are active research topic in photogrammetric and remote sensing communities. Power engineering device monitoring by detecting key objects is important for power safety. In this paper, we introduce a novel method for the reconstruction of self-supporting pylons widely used in high voltage power-line systems from airborne LiDAR data. Our work constructs pylons from a library of 3D parametric models, which are represented using polyhedrons based on stochastic geometry. Firstly, laser points of pylons are extracted from the dataset using an automatic classification method. An energy function made up of two terms is then defined: the first term measures the adequacy of the objects with respect to the data, and the second term has the ability to favor or penalize certain configurations based on prior knowledge. Finally, estimation is undertaken by minimizing the energy using simulated annealing. We use a Markov Chain Monte Carlo sampler, leading to an optimal configuration of objects. Two main contributions of this paper are: (1 building a framework for automatic pylon reconstruction; and (2 efficient global optimization. The pylons can be precisely reconstructed through energy optimization. Experiments producing convincing results validated the proposed method using a dataset of complex structure.

  5. Electricity pylons may be potential foci for the invasion of black cherry Prunus serotina in intensive farmland

    Science.gov (United States)

    Kurek, Przemysław; Sparks, Tim H.; Tryjanowski, Piotr

    2015-01-01

    Electricity pylons are used by birds for nesting platforms, song posts, roosting, perching and therefore as defecation sites. Consequently we predict that pylons may facilitate the dispersal of endozoochorous plants, such as black cherry Prunus serotina, an invasive species in Europe producing fruits that are often eaten by birds. To test the influence of electricity pylons on the abundance of P. serotina in farmland in western Poland we surveyed 124 areas under pylons and 124 paired control plots within fields under power lines. P. serotina occurred under 81.5% of the investigated pylons but only in 2.4% of the control plots. The vast majority of P. serotina plants occurred under pylons (99.9% of 5820 individuals) of which only 0.7% (42 individuals), found under 12 pylons, were fruiting. The few plants in control plots were all seedlings. The density of plants was related to landscape variables; the occurrence of P. serotina was higher when pylons were situated within arable crops, had a lower level of herb cover and were closer to human settlements. These results suggest that one approach to protect semi natural or even anthropogenic landscapes from exotic and invasive species is by encouraging permanent land use involving some form of annual disturbance, such as hay cutting or ploughing.

  6. Integration effects of pylon geometry and rearward mounted nacelles for a high-wing transport

    Science.gov (United States)

    Carlson, John R.; Lamb, Milton

    1987-01-01

    Results of a wind-tunnel study of the effect of pylon cross-sectional shape and tow angle on airplane drag and an aft-mounted nacelle are presented. The 1/24-scale wide-body high-wing transport model was tested in the Langley 16-Foot Transonic Tunnel at free-stream Mach 0.7-0.8 and angles of attack from -3 to 4 degrees. A compression-type pylon is found to have the lowest drag at both Mach 0.7 and 0.8 and to be capable of suppressing the velocities in the inboard region of the pylon-wing junction, reducing the extent of supersonic flow and the probability of flow separation. It is also shown that the D-shaped aft-mounted nacelle has a low interference drag, as do previously tested circular nacelles in the same position.

  7. Juncture flow improvement for wing/pylon configurations by using CFD methodology

    Science.gov (United States)

    Gea, Lie-Mine; Chyu, Wei J.; Stortz, Michael W.; Chow, Chuen-Yen

    1993-01-01

    Transonic flow field around a fighter wing/pylon configuration was simulated by using an implicit upwinding Navier-Stokes flow solver (F3D) and overset grid technology (Chimera). Flow separation and local shocks near the wing/pylon junction were observed in flight and predicted by numerical calculations. A new pylon/fairing shape was proposed to improve the flow quality. Based on numerical results, the size of separation area is significantly reduced and the onset of separation is delayed farther downstream. A smoother pressure gradient is also obtained near the junction area. This paper demonstrates that computational fluid dynamics (CFD) methodology can be used as a practical tool for aircraft design.

  8. Aerodynamic characteristics of a high-wing transport configuration with a over-the-wing nacelle-pylon arrangement

    Science.gov (United States)

    Henderson, W. P.; Abeyounis, W. K.

    1985-01-01

    An investigation has been conducted in the Langley 16-Foot Transonic Tunnel to determine the effects on the aerodynamic characteristics of a high-wing transport configuration of installing an over-the-wing nacelle-pylon arrangement. The tests are conducted at Mach numbers from 0.70 to 0.82 and at angles of attack from -2 deg to 4 deg. The configurational variables under study include symmetrical and contoured nacelles and pylons, pylon size, and wing leading-edge extensions. The symmetrical nacelles and pylons reduce the lift coefficient, increase the drag coefficient, and cause a nose-up pitching-moment coefficient. The contoured nacelles significantly reduce the interference drag, though it is still excessive. Increasing the pylon size reduces the drag, whereas adding wing leading-edge extension does not affect the aerodynamic characteristics significantly.

  9. Gravitational wet-avalanche pressure on pylon-like structures

    Science.gov (United States)

    Sovilla, Betty; Faug, Thierry; Köhler, Anselm; Baroudi, Djebar; Fischer, Jan-Thomas; Thibert, Emmanuel

    2016-04-01

    Low-speed wet-avalanches exert hydrostatic forces on structures which are surface-dependent, however neither the pressure amplification experienced by smaller structure has been quantified and the causes of the amplification understood. In particular, recent wet-snow avalanche pressure measurements, performed with small cells at the "Vallée the la Sionne" test site, indicate significantly higher pressures than those considered by engineering guidelines and common practice rules based only on the contribution of inertial forces. In order to gain a deeper understanding and investigate the relevance of these measurements for structural design, we analyze data collected at the "Vallée the la Sionne" on obstacles of different shapes and dimensions. We show that, the pressure measured on a 1 m2 pressure plate is, on average, 1.8 times smaller than the pressure measured on a 0.008 m2 piezoelectric cell, installed on a 0.60 m wide pylon, and 2.9 times smaller than the pressure measured on a 0.0125 m2 cantilever sensor, extending freely into the snow. The different pressures encountered by the different obstacles is quantitatively explained with a granular force model, assuming the formation of a mobilized volume of snow granules extending from the obstacle upstream. The results underscore the fundamental influence of the dimension of the sensor and the obstacle on pressures. Our study highlights the difficulties that appear in the estimation of forces in the gravitational flow regime, for which force amplification may be caused by this mobilized volume at the scale of the whole structure, but also by plastic wedges, or small dead zones, at the scale of the sensor mounted on a wider structure.

  10. Computations of the unsteady flow about a generic wing/pylon/finned-store configuration

    Science.gov (United States)

    Meakin, Robert L.

    1992-01-01

    An overset grid approach is used to carry out a set of computations of the unsteady flow about a generic wing, pylon, and finned-store configuration. The geometry, discretization procedure, and governing equations are presented. Thin-layer Navier-Stokes solutions are presented for four store separation cases: store in carriage position, store at two different separation positions, and a time-accurate simulation of the forced store separation from the wing pylon carriage. Computational results are compared with wind tunnel data for the three 'static store' cases. Dynamic loads and trajectory data are presented for the forced separation case.

  11. Decoupler pylon - A simple, effective wing/store flutter suppressor. [in fighter/attack aircraft

    Science.gov (United States)

    Reed, W. H.; Foughner, J. T., Jr.; Runyan, H. L., Jr.

    1979-01-01

    As an alternative to alleviating wing/store flutter by conventional passive methods or by more advanced active control methods, a quasi-passive concept, referred to as the decoupler pylon, is investigated which combines desirable features of both methods. Passive soft-spring/damper elements are used to decouple wing modes from store pitch modes, and a low-power control system maintains store alignment under changing mean loads. It is shown by analysis and wind tunnel tests that the decoupler pylon provides substantial increase in flutter speed and makes flutter virtually insensitive to inertia and center-of-gravity location of the store.

  12. Pressure distribution for the wing of the YAV-8B airplane; with and without pylons

    Science.gov (United States)

    Saltzman, Edwin J.; Delfrate, John H.; Sabsay, Catherine M.; Yarger, Jill M.

    1992-01-01

    Pressure distribution data have been obtained in flight at four span stations on the wing panel of the YAV-8B airplane. Data obtained for the supercritical profiled wing, with and without pylons installed, ranged from Mach 0.46 to 0.88. The altitude ranged from approximately 20,000 to 40,000 ft and the resultant Reynolds numbers varied from approximately 7.2 million to 28.7 million based on the mean aerodynamic chord. Pressure distribution data and flow visualization results show that the full-scale flight wing performance is compromised because the lower surface cusp region experiences flow separation for some important transonic flight conditions. This condition is aggravated when local shocks occur on the lower surface of the wing (mostly between 20 and 35 percent chord) when the pylons are installed for Mach 0.8 and above. There is evidence that convex fairings, which cover the pylon attachment flanges, cause these local shocks. Pressure coefficients significantly more negative than those for sonic flow also occur farther aft on the lower surface (near 60 percent chord) whether or not the pylons are installed for Mach numbers greater than or equal to 0.8. These negative pressure coefficient peaks and associated local shocks would be expected to cause increasing wave and separation drag at transonic Mach number increases.

  13. Transonic perturbation analysis of wing-fuselage-nacelle-pylon configurations with powered jet exhausts

    Science.gov (United States)

    Wai, J. C.; Sun, C. C.; Yoshihara, H.

    1982-01-01

    A method using a transonic small disturbance code with successive line over-relaxation is described for treating wing/fuselage configurations with a nacelle/pylon/powered jet. Examples illustrating its use for the NASA transport research model are given. Reasonable test/theory comparisons were obtained.

  14. Investigations on the Influence of the In-Stream Pylon and Strut on the Performance of a Scramjet Combustor

    Directory of Open Access Journals (Sweden)

    Hao Ouyang

    2014-01-01

    Full Text Available The influence of the in-stream pylon and strut on the performance of scramjet combustor was experimentally and numerically investigated. The experiments were conducted with a direct-connect supersonic model combustor equipped with multiple cavities. The entrance parameter of combustor corresponds to scramjet flight Mach number 4.0 with a total temperature of 947 K. The research results show that, compared with the scramjet combustor without pylon and strut, the wall pressure and the thrust of the scramjet increase due to the improvement of mixing and combustion effect due to the pylon and strut. The total pressure loss caused by the strut is considerable whereas pylon influence is slight.

  15. Interactive Multi-objective Optimization Design for the Pylon Structure of an Airplane

    Institute of Scientific and Technical Information of China (English)

    An Weigang; Li Weiji

    2007-01-01

    The pylon structure of an airplane is very complex, and its high-fidelity analysis is quite time-consuming. If posterior preference optimization algorithm is used to solve this problem, the huge time consumption will be unacceptable in engineering practice due to the large amount of evaluation needed for the algorithm. So, a new interactive optimization algorithm-interactive multi-objective particle swarm optimization (IMOPSO) is presented. IMOPSO is efficient, simple and operable. The decision-maker can expediently determine the accurate preference in IMOPSO. IMOPSO is used to perform the pylon structure optimization design of an airplane, and a satisfactory design is achieved after only 12 generations of IMOPSO evolutions. Compared with original design, the maximum displacement of the satisfactory design is reduced, and the mass of the satisfactory design is decreased for 22%.

  16. Aerodynamic design optimization of nacelle/pylon position on an aircraft

    Institute of Scientific and Technical Information of China (English)

    Li Jing; Gao Zhenghong; Huang Jiangtao; Zhao Ke

    2013-01-01

    The arbitrary space-shape free form deformation (FFD) method developed in this paper is based on non-uniform rational B-splines (NURBS) basis function and used for the integral parameterization of nacelle-pylon geometry.The multi-block structured grid deformation technique is established by Delaunay graph mapping method.The optimization objects of aerodynamic characteristics are evaluated by solving Navier-Stokes equations on the basis of multi-block structured grid.The advanced particle swarm optimization (PSO) is utilized as search algorithm,which combines the Kriging model as surrogate model during optimization.The optimization system is used for optimizing the nacelle location of DLR-F6 wing-body-pylon-nacelle.The results indicate that the aerodynamic interference between the parts is significantly reduced.The optimization design system established in this paper has extensive applications and engineering value.

  17. Assessment of Lateral Driving Stability of Automobiles Passing by the Pylon Zone under Cross Wind

    Directory of Open Access Journals (Sweden)

    Dalei Wang

    2012-08-01

    Full Text Available In order to explore the reason of lateral instability of automobile passing by the pylon zone of cablesupported bridge under cross wind, a new evaluation method of lateral driving stability of automobile considering alternative cross wind is established based on multi-objective driving stability criteria and subjective assessment. Typical driving control process and dynamic response of automobile passing by the pylon zone is given by numerical simulation based on steering wheel fixed-control model and straight driving ideal-driver model. Finally, taking a medium-size commercial bus as an example, the reason of its lateral instability is interpreted and the influence of cross wind speed and driving speed on its lateral driving stability is shown by parameter study.

  18. Numerical analysis on bearing capacity of middle pylon caisson foundation of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Shao Guojian; Hu Feng; Gu Lijun

    2012-01-01

    Because of the computation difficulty of the beating capacity of large underwater caisson foundation on thick overburden layer ground, the geotechnieal software FLAC3D was utilized in the 3D numerical analysis on the bearing capacity of middle pylon foundation. From the computational results, it is concluded that the caisson foundation has a good bearing capacity on thick overburden layer ground and the beating capacity can be improved assuming that the soil near the area of basal comer is reinforced.

  19. Assessment of Lightning Shielding Performance of a 400 kV Double-Circuit Fully Composite Pylon

    DEFF Research Database (Denmark)

    Jahangirl, Tohid; Bak, Claus Leth; Silva, Filipe Miguel Faria da

    2016-01-01

    . In Europe alone, 28.000 km of 400 kV transmission line is needed by 2020 to fulfil the aim of providing 20% of Europe’s energy from green energies. It means that more than 100.000 new pylons will be needed [1]. For this reason, the next generation of overhead line is introduced, by developing new design......Modern day overhead transmission lines are taking a giant leap in modernization, with the change in power generation from fossil fuels to renewable sources such as solar power, hydro power and wind power. The renewable generation needs to be connected to a large scale high voltage transmission grid...... in the electrical design of the pylon which is also important in terms of mechanical and material designs. In this paper, the weak and strong points of the preliminary assigned shielding angle for the pylon are investigated and subsequently, an acceptable shielding angle will be derived from the electro...

  20. Jet engine nozzle exit configurations, including projections oriented relative to pylons, and associated systems and methods

    Science.gov (United States)

    Mengle, Vinod G. (Inventor); Thomas, Russell H. (Inventor)

    2012-01-01

    Nozzle exit configurations and associated systems and methods are disclosed. An aircraft system in accordance with one embodiment includes a jet engine exhaust nozzle having an internal flow surface and an exit aperture, with the exit aperture having a perimeter that includes multiple projections extending in an aft direction. Aft portions of individual neighboring projections are spaced apart from each other by a gap, and a geometric feature of the multiple can change in a monotonic manner along at least a portion of the perimeter. Projections near a support pylon and/or associated heat shield can have particular configurations, including greater flow immersion than other projections.

  1. 超燃燃烧室肋片构型数值研究%Numerical simulation on pylon pattern in a supersonic combustor

    Institute of Scientific and Technical Information of China (English)

    王应洋; 李旭昌; 王宏宇; 王旭东

    2016-01-01

    The numerical simulation was carried out to investigate the cold flow characteristics of small pylon aided gaseous fuel injection in the supersonic combustion.Ten pylon patterns were evaluated for mixing enhancement,fuel penetration and total pressure loss coefficient.It is noted that total pressure loss is leaded mainly by the wall and jet.Cases with Pylon A and Pylon D can get smal-ler total pressure loss than case with only transverse jet.The bigger rear face of the pylon can provide more low pressure depression which might result in a rapid diffusion of fuel but lower fuel penetration.The angle of rear face has little influence on the mixing effi-ciency.Moreover,the front face has a stronger effect on mixing efficiency than the change of the rear face.The patterns of Pylon D, Pylon I and Pylon J have a further engineering research value.%为进一步研究不同肋片构型对后方射流的影响规律,运用数值模拟方法,研究了统一特征尺寸下不带前引导面与带前引导面等10种不同构型肋片流场特性差异。研究发现,肋片后低动压喷射的总压损失主要由壁面与横向射流产生,与传统横向喷流算例相比,带Pylon A和Pylon D的算例总压损失有所减小;肋片后缘面越大能提供的低压区越大,后缘面过大燃料组分扩散过早,羽流质量中心高度未必越大,无论后缘面前倾或后倾流场特性无明显改善;前引导面对掺混特性的影响效果大于后缘面对掺混特性的影响效果,Pylon D、Pylon I及Pylon J构型的肋片最具进一步研究价值。

  2. Nonlinear Stability Analysis of a Composite Girder Cable-Stayed Bridge with Three Pylons during Construction

    Directory of Open Access Journals (Sweden)

    Xiaoguang Deng

    2015-01-01

    Full Text Available Based on the nonlinear stability analysis method, the 3D nonlinear finite element model of a composite girder cable-stayed bridge with three pylons is established to research the effect of factors including geometric nonlinearity, material nonlinearity, static wind load, and unbalanced construction load on the structural stability during construction. Besides, the structural nonlinear stability in different construction schemes and the determination of temporary pier position are also studied. The nonlinear stability safety factors are calculated to demonstrate the rationality and safety of construction schemes. The results show that the nonlinear stability safety factors of this bridge during construction meet the design requirement and the minimum value occurs in the maximum double cantilever stage. Besides, the nonlinear stability of the structure in the side of edge-pylon meets the design requirement in the two construction schemes. Furthermore, the temporary pier can improve the structure stability, effectively, and the actual position is reasonable. In addition, the local buckling of steel girder occurs earlier than overall instability under load in some cable tension stages. Finally, static wind load and the unbalanced construction load should be considered in the stability analysis for the adverse impact.

  3. Assessment of Lightning Shielding Performance of a 400 kV Double-Circuit Fully Composite Transmission Line Pylon

    DEFF Research Database (Denmark)

    Jahangiri, Tohid; Bak, Claus Leth; Silva, Filipe Miguel Faria da

    2016-01-01

    . In Europe alone, 28.000 km of 400 kV transmission line is needed by 2020 to fulfil the aim of providing 20% of Europe’s energy from green energies. It means that more than 100.000 new pylons will be needed [1]. For this reason, the next generation of overhead line is introduced, by developing new design....... The integration of insulators in the cross-arm design is the prominent feature of the fully composite pylon in comparison with conventional towers. The unibody cross-arm of the pylon is expected to have 30 degree inclination and all conductors are fixed to the top of the cross-arm by cable clamps or special high......-quality insulation sections. Thus, the configuration of phase conductors on the cross-arm is in the form of diagonal and differs from other widely used configurations in overhead transmission lines i.e. horizontal, delta and vertical configurations. Unlike traditional steel lattice towers, the composite pylon does...

  4. A State of the Art Review- Methods to Evaluate Electrical Performance of Composite Cross-arms and Composite-based Pylons

    DEFF Research Database (Denmark)

    Wang, Qian; Bak, Claus Leth; Silva, Filipe Miguel Faria da;

    2016-01-01

    performance need to be studied. This paper sums up experience and key advances on testing methods to evaluate electrical performance of composite cross-arms and composite-based pylons. Based on state of the art review, several feasible testing methods that can be used to verify the feasibility of the novel......A novel uni-body composite pylon has been proposed for 400 kV transmission lines with advantages of compacted size, friendly looking and cost competitiveness. As its configuration is quite different from the traditional lattice pylon, its electrical performance needs in-depth investigation...

  5. Software development of modeling assistant for continuous suspension bridges with multi-pylon

    Institute of Scientific and Technical Information of China (English)

    Zhong Jianchi; Chen Ke; Chen Yunhai; Lu jianming

    2012-01-01

    Building a reasonable and accurate finite element model is the first and critical step for structural analysis of complicated bridge. In this article, modeling assistant for continuous suspension with multi-pylon is developed based on ~ Net platform, with VB. Net, C# language and OpenGL graphic technique. With parameterized modeling method, finite element model of this kind of bridge can be built quickly and accurately, and multi-type element modeling with uniform parameters is realized. With advanced graphic technique, three-dimensional model graph can be real-timely previewed for intuitive data check. With an example of practice project, the accuracy and feasibility of this modeling method and practicality of this software are verified.

  6. Horizontally opposed trunnion forward engine mount system supported beneath a wing pylon

    Science.gov (United States)

    Seaquist, John D. (Inventor); Culbertson, Chris (Inventor)

    2000-01-01

    The present invention relates to an engine mount assembly for supporting an aircraft engine in aft-cantilevered position beneath the aircraft wing. The assembly includes a pair forward engine mounts positioned on opposite sides of an integrally formed yoke member wrapped about the upper half of the engine casing. Each side of the yoke is preferably configured as an A-shaped frame member with the bottom portions joining each other and the pylon. To prevent backbone bending of the engine trunnion assembly, the forward engine mounts supported at opposite ends of the yoke engage the casing along its centerline. The trunnion assembly is preferably constructed of high strength titanium machined and/or forged.

  7. Theoretical prediction of thick wing and pylon-fuselage-fanpod-nacelle aerodynamic characteristics at subcritical speeds. Part 1: Theory and results

    Science.gov (United States)

    Tulinius, J. R.

    1974-01-01

    The theoretical development and the comparison of results with data of a thick wing and pylon-fuselage-fanpod-nacelle analysis are presented. The analysis utilizes potential flow theory to compute the surface velocities and pressures, section lift and center of pressure, and the total configuration lift, moment, and vortex drag. The skin friction drag is also estimated in the analysis. The perturbation velocities induced by the wing and pylon, fuselage and fanpod, and nacelle are represented by source and vortex lattices, quadrilateral vortices, and source frustums, respectively. The strengths of these singularities are solved for simultaneously including all interference effects. The wing and pylon planforms, twists, cambers, and thickness distributions, and the fuselage and fanpod geometries can be arbitrary in shape, provided the surface gradients are smooth. The flow through nacelle is assumed to be axisymmetric. An axisymmetric center engine hub can also be included. The pylon and nacelle can be attached to the wing, fuselage, or fanpod.

  8. A State of the Art Review- Methods to Evaluate Electrical Performance of Composite Cross-arms and Composite-based Pylons

    DEFF Research Database (Denmark)

    Wang, Qian; Bak, Claus Leth; Silva, Filipe Miguel Faria da;

    2016-01-01

    A novel uni-body composite pylon has been proposed for 400 kV transmission lines with advantages of compacted size, friendly looking and cost competitiveness. As its configuration is quite different from the traditional lattice pylon, its electrical performance needs in-depth investigation...... and evaluation, for which electrical testing methods are essential. However, as research on composite-based pylons is still in initial stage, leaving international standards and theoretical analysis on this topic very limited, effective testing methods to evaluate the fully composite pylon’s electrical...... performance need to be studied. This paper sums up experience and key advances on testing methods to evaluate electrical performance of composite cross-arms and composite-based pylons. Based on state of the art review, several feasible testing methods that can be used to verify the feasibility of the novel...

  9. An Experimental Study into Pylon, Wing, and Flap Installation Effects on Jet Noise Generated by Commercial Aircraft

    Science.gov (United States)

    Perrino, Michael

    A pylon bottom bifurcation and a wing with variable flaps were designed and built to attach to a scaled model of a coaxial exhaust nozzle system. The presence of the pylon bifurcation, wing, and flaps modify the characteristics of the exhaust flow forc- ing asymmetric flow and acoustics. A parametric study was carried out for assessing and relating the flow field characteristics to the near-field pressure and far-field acous- tic spectra. The flow field was investigated experimentally using both stream-wise and cross-stream PIV techniques where the near-field pressure and far-field acoustic spectra were measured using microphone arrays. Contour mapping of the flow field characteristics (e.g. mean velocity and turbulence kinetic energy levels) and near-field acoustics with and without installation effects were used to explain the changes in the far-field acoustics.

  10. X-38 on B-52 Wing Pylon - View from Observation Window

    Science.gov (United States)

    1997-01-01

    addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet. It is 156 feet long and has a wing span of 185 feet. The heaviest load it has carried was the No. 2 X-15 aircraft at 53,100 pounds. Project manager for the aircraft is Roy Bryant.

  11. Aerodynamic analysis for aircraft with nacelles, pylons, and winglets at transonic speeds

    Science.gov (United States)

    Boppe, Charles W.

    1987-01-01

    A computational method has been developed to provide an analysis for complex realistic aircraft configurations at transonic speeds. Wing-fuselage configurations with various combinations of pods, pylons, nacelles, and winglets can be analyzed along with simpler shapes such as airfoils, isolated wings, and isolated bodies. The flexibility required for the treatment of such diverse geometries is obtained by using a multiple nested grid approach in the finite-difference relaxation scheme. Aircraft components (and their grid systems) can be added or removed as required. As a result, the computational method can be used in the same manner as a wind tunnel to study high-speed aerodynamic interference effects. The multiple grid approach also provides high boundary point density/cost ratio. High resolution pressure distributions can be obtained. Computed results are correlated with wind tunnel and flight data using four different transport configurations. Experimental/computational component interference effects are included for cases where data are available. The computer code used for these comparisons is described in the appendices.

  12. Estimation of Fundamental Frequency of Multi-Pylon Suspension Bridges%多塔连跨悬索桥基频估算方法

    Institute of Scientific and Technical Information of China (English)

    王本劲; 马如进; 陈艾荣

    2011-01-01

    近年来,在跨海大桥的兴建中,多塔连跨悬索桥的方案引起了越来越多的关注.但由于中间桥塔处约束较弱,其动力特性与中塔刚度紧密相关,现有规范中的基频估算公式无法适用.基于能量原理,提出了适用于多塔连跨悬索桥的基频估算方法,最后给出了中塔刚度变化下的算例结果比较.结果表明,该估算方法有较高的精度,可为实际工程提供参考.%As long-span cross-sea bridges being constructed in recent years, multi-pylon suspension bridges attract increasing attention. However, because of the weak constrains of the mid - pylon, the dynamic characteristics is highly related to the rigidity of the mid-pylon, and the existing fundamental frequency estimation formula in current code is not available. Based on the energy principle, a new formula that can be applied to multi-pylon suspension bridges was proposed. Then the estimating results with respect to the changing rigidity of mid-pylon was given, which showed that the proposed formula has enough accuracy to be utilized in practical projects.

  13. Unstructured grid solutions to a wing/pylon/store configuration using VGRID3D/USM3D

    Science.gov (United States)

    Parikh, Paresh; Pirzadeh, Shahyar; Frink, Neal T.

    1992-01-01

    The purpose of this paper is to validate an inviscid flow solution package based on a new unstructured grid methodology using experimental data on a wing/pylon/store configuration. The solution package consists of an advancing front unstructured grid generator, VGRID3D, and an efficient Euler equation solver, USM3D. Comparisons of computed data versus experimental data are made for two free-stream Mach numbers at five store locations relative to the wing. Both rigid body aerodynamics and mutual interference effects are explored. A very good agreement is observed between computed and wind tunnel data.

  14. The Influence of No-Primer Adhesives and Anchor Pylons Bracket Bases on Shear Bond Strength of Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Andrea Scribante

    2013-01-01

    Full Text Available Objective. The aim of this study was to compare the shear bond strength (SBS and adhesive remnant index (ARI scores of no-primer adhesives tested with two different bracket bases. Materials and Methods. 120 bovine permanent mandibular incisors were divided into 6 groups of 20 specimens. Two brackets (ODP with different bracket bases (anchor pylons and 80-gauge mesh were bonded to the teeth using a conventional adhesive (Transbond XT and two different no-primer adhesive (Ortho Cem; Heliosit systems. Groups were tested using an instron universal testing machine. SBS values were recorded. ARI scores were measured. SEM microphotographs were taken to evaluate the pattern of bracket bases. Statistical analysis was performed. ANOVA and Tukey tests were carried out for SBS values, whereas a chi-squared test was applied for ARI scores. Results. Highest bond strength values were reported with Transbond XT (with both pad designs, Ortho Cem bonded on anchor pylons and Heliosit on 80-gauge mesh. A higher frequency of ARI score of “3” was reported for Transbond XT groups. Other groups showed a higher frequency of ARI score “2” and “1.” Conclusion. Transbond XT showed the highest shear bond strength values with both pad designs.

  15. A 3D mathematical model to predict spinal joint and hip joint force for trans-tibial amputees with different SACH foot pylon adjustments.

    Science.gov (United States)

    Yu, Chung-huang; Hung, Yu-Cheng; Lin, Yang-Hua; Chen, Guan-Xun; Wei, Shun-Hwa; Huang, Chang-Hung; Chen, Chen-Sheng

    2014-09-01

    A solid-ankle cushioned heel (SACH) foot is a non-joint foot without natural ankle function. Trans-tibial amputees may occur toe scuffing in the late swing phase due to a lack of active dorsiflexion. To address this problem, clinical guidelines suggests shortening the pylon to produce a smooth gait. However, this causes a leg length discrepancy, induces asymmetry in the hip joint, and causes an overload of L5/S1 joint force. Therefore, this study aimed to investigate the influence of different prosthesis pylons on the hip joint and L5/S1 joint forces. Ten subjects were recruited using leg length for normalisation. Four different pylon reductions (0%, 1%, 2%, and 3%) were used for gait analysis. A Vicon system and force plates were used to collect kinematic data and ground reaction force, respectively. The software package MATLAB was used to create a mathematical model for evaluating the symmetry and force of the hip joint and the low back force of the L5/S1 joint. The model was validated by the correlation coefficient (CC=0.947) and root mean square (RMS=0.028 BW). The model estimated that the 1% group had a symmetrical hip joint force and a lower L5/S1 joint force in the vertical direction. This study indicates that a 1% pylon shortening on a SACH prosthesis is appropriate for a trans-tibial amputee.

  16. Theoretical prediction of thick wing and pylon-fuselage-fanpod-nacelle aerodynamic characteristics at subcritical speeds. Part 2: Computer program description

    Science.gov (United States)

    Kojima, J.; Tulinius, J. R.

    1974-01-01

    The procedures required to operate the thick wing and pylon-fuselage-fanpod-nacelle computer program are presented. The program computes surface velocities and pressure, section loads, and total configuration loads and pitching moment. Potential flow theory is used to compute the surface pressures and the associated lift, moment, and vortex drag. The skin friction drag is also computed.

  17. Close-up of Wing Fit Check of Pylon to Carry the X-38 on B-52 Launch Aircraft

    Science.gov (United States)

    1997-01-01

    Tom McMullen, Chief of Dryden's Experimental Fabrication Shop, makes adjustments to the new pylon for NASA's X-38 during a fit-check on NASA's B-52 at the Dryden Flight Research Center, Edwards, California, in 1997. The fit-check was the first time the 1,200-pound steel pylon was mated to the B-52 following fabrication at Dryden by the Center's Experimental Fabrication Shop. The pylon was built as an 'adapter' to allow the X-38 to be attached to and launched from the B-52's wing. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST

  18. Installation effects of long-duct pylon-mounted nacelles on a twin-jet transport model with swept supercritical wing

    Science.gov (United States)

    Lee, E. E., Jr.; Pendergraft, O. C., Jr.

    1985-01-01

    The installation interference effects of an underwing-mounted, long duct, turbofan nacelle were evaluated in the Langley 16-Foot Transonic Tunnel with two different pylon shapes installed on a twin engine transport model having a supercritical wing swept 30 deg. Wing, pylon, and nacelle pressures and overall model force data were obtained at Mach numbers from 0.70 to 0.83 and nominal angles of attack from -2 deg to 4 deg at an average unit Reynolds number of 11.9 x 1,000,000 per meter. The results show that adding the long duct nacelles to the supercritical wing, in the near sonic flow field, changed the magnitude and direction of flow velocities over the entire span, significantly reduced cruise lift, and caused large interference drag on the nacelle afterbody.

  19. Visual Quality Control Techniques Used to Concrete Pylon Column Construction%混凝土塔柱施工外观质量控制技术

    Institute of Scientific and Technical Information of China (English)

    韦理仁; 张家伦; 陈新

    2016-01-01

    To improve the visual quality of concrete pylon columns of urban bridges ,the con‐struction of the pylon columns of Jiangshun Bridge was cited as an example ,to study the key visual quality control techniques used during the pylon column construction .The formwork was rational‐ly divided according to the structural characteristics of the pylon columns ,the joints between every two divisions adopts tongue‐and‐groove joints ,and the connection of the arc‐chamfered steel form‐work and the timber formwork was optimized .The WISA plate and the I‐shaped timber back ribs were connected by nails driven from the opposite side .Besides the tie rods ,there are embedded climbing cones and fining twisted steel bars installed at the base opening of the formwork ,aiming to gain the twofold tightening effect .A testing block of the pylon saddle was prepared ,comparison was made among different mold release agents ,and the salad oil was finally chosen as the release agent .During the construction of the pylon column concrete ,the timbers with length equal to the thickness of the pylon column walls were used as inner shoring ,to ensure the width of the form‐work top opening .The horizontal nails in the construction joints at the top opening of the form‐work were backed by through‐length battens to control flatness .A pump washing cycling system was designed for the ordered draining of waste water .By taking the aforementioned measures ,the pylon columns of the Jiangshun Bridge were constructed to be solid columns with pleasing sur‐f aces .%为提高城市桥梁混凝土塔柱的外观质量,以江顺大桥桥塔塔柱施工为例,对塔柱施工中混凝土外观质量控制的关键技术进行研究。结合塔柱结构特点合理进行模板分块,分块拼缝采用企口缝形式,并对圆弧倒角钢模与木模的连接进行优化处理;W IS A面板与木工字背肋的连接采用反面打钉的连接方式;模板底口除了设置拉杆

  20. Experimental and Computational Study of the Flow past a Simplified Geometry of an Engine/Pylon/Wing Installation at low velocity/moderate incidence flight conditions

    Science.gov (United States)

    Bury, Yannick; Lucas, Matthieu; Bonnaud, Cyril; Joly, Laurent; ISAE Team; Airbus Team

    2014-11-01

    We study numerically and experimentally the vortices that develop past a model geometry of a wing equipped with pylon-mounted engine at low speed/moderate incidence flight conditions. For such configuration, the presence of the powerplant installation under the wing initiates a complex, unsteady vortical flow field at the nacelle/pylon/wing junctions. Its interaction with the upper wing boundary layer causes a drop of aircraft performances. In order to decipher the underlying physics, this study is initially conducted on a simplified geometry at a Reynolds number of 200000, based on the chord wing and on the freestream velocity. Two configurations of angle of attack and side-slip angle are investigated. This work relies on unsteady Reynolds Averaged Navier Stokes computations, oil flow visualizations and stereoscopic Particle Image Velocimetry measurements. The vortex dynamics thus produced is described in terms of vortex core position, intensity, size and turbulent intensity thanks to a vortex tracking approach. In addition, the analysis of the velocity flow fields obtained from PIV highlights the influence of the longitudinal vortex initiated at the pylon/wing junction on the separation process of the boundary layer near the upper wing leading-edge.

  1. Study on longitudinal optimum location of transport aircraft nacelle and pylons%运输机短舱挂架纵向位置优选数值研究

    Institute of Scientific and Technical Information of China (English)

    雷熙薇; 桑为民; 段卓毅; 冯海勇; 张彦军

    2011-01-01

    针对运输机的翼/身/架/舱干扰问题,本文基于Euler方程,采用笛卡尔直角网格,应用有限体积法对全机绕流流场进行数值计算,分析和比较了短舱挂架不同前伸量、下沉量的影响,提出了基于最佳前伸量和下沉量的优选配合位置,并与初始位置的全机气动特性进行对比.结果表明,获得的短舱挂架优选配合位置使全机气动特性得到了明显改善和提高.%To resolve the problem of the interference between the wing/body/pylon/nacelle of the large transport aircraft, this paper uses the Elder equation with the Cartesian grid and finite volume method to calculate the flow characteristic of the aircraft with different amounts of protrusion and subsidence of the nacelle and pylon, also analyse and compare the aerodynamic performance. The optimized position is selected and demonstrated. The numerical result shows that the aerodynamic performance of the transportation aircraft is obviously improved for the new optimized position of the nacelle and pylon.

  2. 翼吊发动机吊架结构等效建模及减振特性分析%Equivalent Modeling and the Damping Characteristics Analysis of the Wine-mounted Engine Pylon

    Institute of Scientific and Technical Information of China (English)

    宋波涛; 贺尔铭; 张钊

    2012-01-01

    In order to verify the damping effect of the wing-mounted engine pylon structure, the structural dynamics of the engine pylon must be analyzed. An equivalent model of engine pylon is build by the finite element software ANSYS. The first ten non-zero modals of the pylon are calculated. The damping characteristics of the pylon is analyzed under three typical conditions (takeoff, cruise, flight idle) , and the relationship between the damping effect and the dynamic stiffness is researched. The results show that the engine pylon design achieves good damping effect, however, due to the dynamic stiffness of the pylon increases with the exciting force frequency's increment, the high-frequency damping effect is slightly reduced.%为了验证翼吊发动机吊架结构对发动机振动传递的减振效果,必须对其进行相关的结构动力学分析.根据实际发动机吊架结构,采用ANSYS软件建立了吊架结构的等效模型,并对其进行了振动模态分析.在发动机三种典型工况(起飞、巡航、空慢)的实测载荷作用下,分析了吊架结构的减振特性,并研究了吊架结构减振效果与结构动刚度的关系.研究结果表明,发动机吊架结构设计具有较好的减振效果,但由于吊架结构的动刚度随激振力频率变大而增大,其高频减振效果稍有降低.

  3. Research on Parameter Selection of Low RCS Serrated Pylon%低RCS齿形挂架参数选择研究

    Institute of Scientific and Technical Information of China (English)

    黄沛霖; 马东立; 武哲

    2001-01-01

    常规飞机的机翼与外挂架构成90°的二面角,成为飞机侧向的重要散射源.为求在不改变机体结构的前提下减缩飞机侧向RCS,采用齿形方案改变了挂架外形,消除了直角二面角结构,削弱了耦合效应.计算结果显示,改形的国产某型战斗机的机翼-外挂架结构的RCS在侧向重点姿态角内降低了9~13dBsm,证明了齿形改形方案能明显改善飞机侧向的耦合散射效应.在计算过程中使用了射线追踪法.%Wing and pylon form a structure which is the major lateral scattering sources of an ordinary aircraft because a dihedral angle of ninety degrees is formed. In order to implement a reduction of RCS without any other change on the aircraft, the outline of the pylon is changed by applying a serrated scheme and the right dihedral angle structure is removed, so coupling effect is waken. Computation results reveal that the RCS of the wing-pylon structure on a domestic active fighter plane is reduced by 9 to 13 dBsm in the typical lateral attitude angle range. So it is proved that the serrated scheme could be significant useful in the control of the lateral coupling RCS of the ordinary aircraft. The ray trace method is used to do the calculation of the RCS.

  4. The X-38 Vehicle 131R drops away from its launch pylon on the wing of NASA's NB-52B mothership as it

    Science.gov (United States)

    2001-01-01

    The X-38 prototype of the Crew Return Vehicle for the International Space Station drops away from its launch pylon on the wing of NASA's NB-52B mothership as it begins its eighth free flight on Thursday, Dec. 13, 2001. The 13-minute test flight of X-38 vehicle 131R was the longest and fastest and was launched from the highest altitude to date in the X-38's atmospheric flight test program. A portion of the descent was flown under remote control by a NASA astronaut from a ground vehicle configured like the CRV's interior before the X-38 made an autonomous landing on Rogers Dry Lake.

  5. Experimental static aerodynamic forces and moments at high subsonic speeds on a missile model during simulated launching from the midsemispan location of a 45 degree sweptback wing-fuselage-pylon combination

    Science.gov (United States)

    Alford, William J; King, Thomas, Jr

    1957-01-01

    An investigation was made at high subsonic speeds in the Langley high-speed 7- by 10-foot tunnel to determine the static aerodynamic forces and moments on a missile model during simulated launching from the midsemispan location of a 45 degree sweptback wing-fuselage-pylon combination. The results indicated significant variations in all the aerodynamic components with changes in chordwise location of the missile. Increasing the angle of attack caused increases in the induced effects on the missile model because of the wing-fuselage-pylon combination. Increasing the Mach number had little effect on the variations of the missile aerodynamic characteristics with angle of attack except that nonlinearities were incurred at smaller angles of attack for the higher Mach numbers. The effects of finite wing thickness on the missile characteristics, at zero angle of attack, increase with increasing Mach number. The effects of the pylon on the missile characteristics were to causeincreases in the rolling-moment variation with angle of attack and a negative displacement of the pitching-moment curves at zero angle of attack. The effects of skewing the missile in the lateral direction relative to and sideslipping the missile with the wing-fuselage-pylon combination were to cause additional increments in side force at zero angle of attack. For the missile yawing moments the effects of changes in skew or sideslip angles were qualitatively as would be expected from consideration of the isolated missile characteristics, although there existed differences in theyawing-moment magnitudes.

  6. Pylon Areas - USACE IENC

    Data.gov (United States)

    Department of Homeland Security — These inland electronic Navigational charts (IENCs) were developed from available data used in maintenance of Navigation channels. Users of these IENCs should be...

  7. Nacelle/pylon interference study on a 1/17th-scale, twin-engine, low-wing transport model

    Science.gov (United States)

    Pendergraft, Odis C., Jr.; Ingraldi, Anthony M.; Re, Richard J.; Kariya, Timmy T.

    1989-01-01

    NASA-Langley has conducted wind tunnel tests of a twin-engine, low-wing transport aircraft configuration with 10.8-aspect ratio supercritical wing, in order to ascertain and compare the wing/nacelle interference effects of through-flow nacelled simulating 'superfan' very high bypass ratio (BPR=20) turbofans and current-technology (BPR=6) turbofans. Measurements of model forces and moments have been obtained, together with extensive external static pressure measurement on the model's wings, nacelles, and pylons in the Mach 0.5-0.8 range, at angles of attack in the -4 to +8 deg range. The superfan nacelles exhibit a significant advantage over current-technology turbofan nacelles, when the superfan's SFC gains are taken into account.

  8. Structural Design of Multi-Pylon Cable-Stayed Bridge with Corrugated Steel Webs for Chaoyang Bridge in Nanchang%南昌朝阳大桥波形钢腹板多塔斜拉桥结构设计

    Institute of Scientific and Technical Information of China (English)

    陈水生; 钟志斌; 桂水荣; 刘旭政; 钟汉清

    2014-01-01

    The PC composite box girder with corrugated steel webs is applicable to bridges with a variety of structural types ,which exhibits superior durability and economic features as com‐pared with the common concrete box girder .The cable‐stayed bridge with corrugated steel webs is regarded as the type of structure where composite box girder with corrugated steel webs is ingen‐iously used ,making better use of the properties of the two structures . The main navigational bridge of the Chaoyang Bridge in Nanchang is a (79+ 5 × 150+79) m continuous composite box girder cable‐stayed bridge with corrugated steel webs .The bridge has six pylons and the stay ca‐bles are arranged in single cable plane .In addition ,the bridge has two layers of decks ,on the up‐per deck ,dual eight vehicle lanes (four lanes each side) are arranged and pedestrian and non‐mo‐torized vehicle lanes are arranged on the lower deck .Based on the analysis and study undertaken , small side span‐to‐main span ratio was chosen .Due to the multiple pylons ,the load path from the intermediate pylons to the side pylons is long and the effect of ancillary piers in the side spans is minimal ,as a result ,no ancillary piers are installed .In the structural system ,the pylons and the main girder are fixed while the girder and piers are separated .The box girder is 43 .84 m wide , with transverse steel diaphragms .The stay cables are fanned out in single cable plane .The pylon looks like the Chinese character“合“ ,and double bearings are installed at the pylons .T he stay vi‐bration mitigation bearings are used as the vibration mitigation and isolation devices of the super‐structure ,which are installed below the two side pylons .%波形钢腹板PC组合箱梁适用于不同结构形式的桥梁,相比普通混凝土箱梁具有显著的耐久性和经济性,波形钢腹板斜拉桥将波形钢腹板组合箱梁应用到斜拉桥中,充分发挥了2种结构的特点。南昌朝

  9. 低散射目标支撑金属支架的外形参数优化%Shape Optimization of Target Support Low-scattering Metal Pylons

    Institute of Scientific and Technical Information of China (English)

    安大卫; 李志平; 陈五一

    2015-01-01

    Low-scattering metal pylon for target supporting is of great importance in the electromagnetic scattering measurement for stealth aircraft design and manufacture. The proper shape parameters can re-duce the pylon scattering and its deformation,which is very important to decrease the measurement error. Through theoretical calculating,software simulation and compact range measurements,the relationships be-tween the metal pylon shape parameters and the pylon scattering are analyzed according to the edge diffrac-tion and traveling wave scattering theories. Based on the theoretical analysis,the 3D models with variable parameters for optimization are created in FEKO software and finally the optimum pylon tilt angle and cross section are obtained for the pylon working in C-band and X-band. The comparison of the mechanical de-formation is also considered,so the optimization is achieved according to both the scattering and mechanical performance. The recommended tilt angle of 60o is selected as the optimum tilt angle, and 70o for the heavy-load pylon. An optimum asymmetric ogival cross section whose length of the back part is 26. 9% of the total length is raised and it can keep reducing the pylon scattering both in the vertical polarization and the horizontal polarization in balance. The conclusion that difference between the edge diffraction edge and traveling wave scattering trends with the varying pylon tilt angle determines that there should be an opti-mum tilt angle is drawn. A design principle for the optimum pylon cross section is raised that both the leading edge wedge angle and the length of the cross section in the illumination zone should be reduced simultaneously. The work is of great importance in the engineering design of low-scattering metal pylon and reducing the error of the electromagnetic scattering measurements.%低散射金属支架用于电磁散射测量中的目标支撑,是隐身飞行器设计制造过程中的重要装备。合适的支架外

  10. Construction Techniques for Upper Cross Beams of Pylons of Huanggang Changjiang River Rail-cum-Road Bridge%黄冈公铁两用长江大桥桥塔上横梁施工技术

    Institute of Scientific and Technical Information of China (English)

    张德致; 张敏; 代皓; 邓永锋

    2013-01-01

    The main bridge of Huanggang Changjiang River Rail-cum-Road Bridge is a cablestayed bridge with a main span 567 m.The upper cross beams of the pylons of the bridge are the prestressed concrete single-cell single-box structures,each being 23.85 m long,8.4 m wide and 8.0 m deep.The pylons were constructed by the hydraulic self-climbing formwork and the upper cross beams and the upper pylon columns were constructed asynchronously.A kind of the construction scheme was adopted for the casting scaffoldings of the upper cross beams,i.e.the shear groves were set in the inner sides of each two pylon columns and the counter tensioned steel brackets were installed as the supports of the scaffoldings.The concrete of the upper cross beam of a pylon was cast in two layers and before the second layer was cast,parts of the prestressing bars were tensioned.The MIDAS Civil was used to establish the model and the construction process of the upper cross beam was analyzed.The results of the analysis show that the casting of the concrete in layers and the tensioning of the prestressing bars in times can effectively reduce the loads on the scaffoldings and the stress of the concrete can satisfy the relevant requirements in the codes.The construction techniques for the upper cross beams of the pylons of the bridge are practical and feasible.With the techniques,the rapid construction of the pylons is achieved.%黄冈公铁两用长江大桥主桥为主跨567 m的斜拉桥.该桥桥塔上横梁为单箱单室预应力混凝土结构,长23.85m、宽8.4m、高8.0m,桥塔采用液压自爬模施工,上横梁与上塔柱采用异步施工.上横梁浇筑支架采用在两塔柱内侧设置剪力槽,安放对拉式钢牛腿作为支架受力支承点的方案.上横梁分2层浇筑,在第2层混凝土浇筑前张拉部分预应力筋.采用MIDAS Civil建模分析上横梁施工过程,结果表明,分层浇筑和分次张拉预应力钢筋可以有效减小现浇支架的荷载,且混凝土应

  11. Installation effects of wing-mounted turbofan nacelle-pylons on a 1/17-scale, twin-engine, low-wing transport model

    Science.gov (United States)

    Pendergraft, Odis C., Jr.; Ingraldi, Anthony M.; Re, Richard J.; Kariya, Timmy T.

    1992-01-01

    A twin-engine, low-wing transport model, with a supercritical wing of aspect ratio 10.8 designed for a cruise Mach number of 0.77 and a lift coefficient of 0.55, was tested in the Langley 16-Foot Transonic Tunnel. The purpose of this test was to compare the wing-nacelle interference effects of flow-through nacelles simulating superfan engines (very high bypass ratio (BPR is approx. = 18) turbofan engines) with the wing-nacelle interference effects of current-technology turbofans (BPR is approx. = 6). Forces and moments on the complete model were measured with a strain-gage balance, and extensive external static-pressure measurements (383 orifice locations) were made on the wing, nacelles, and pylons of the model. Data were taken at Mach numbers from 0.50 to 0.80 and at model angles of attack from -4 deg to 8 deg. Test results indicate that flow-through nacelles with a very high bypass ratio can be installed on a low-wing transport model with a lower installation drag penalty than for a conventional turbofan nacelle at a design cruise Mach number of 0.77 and lift coefficient of 0.55.

  12. Study on the Aerodynamic Characteristics of a Single-pylon Cable-stayed Bridge Girder by Numerical Simulation and Wind Tunnel Test

    Directory of Open Access Journals (Sweden)

    Longqi Zhang

    2014-09-01

    Full Text Available The wind induced vibration is one of the key technical problems for long-span bridge design. Therefore, a study on the aerodynamic characteristics of a single-pylon cable-stayed bridge girder is carried out in this paper. The aerostatic coefficient of the bridge girder, including both construction state and service state, is investigated by wind tunnel test with varying wind attack angle. Then based on the computational fluid dynamics (CFD method, the flow field around the bridge girder is visualized numerically. The risk of vortex-induced vibration (VIV is qualitatively evaluated by analyzing the flow features and by considering the Scruton number (Sc. Later a dynamic section model is tested in wind tunnel and the VIV phenomenon is observed subsequently. Results show that the aerodynamic stability is assured by the positive slope of the lift coefficient. The VIV response is influenced by the structural damping and the bridge accessory. The amplitude of VIV response can be lower by increasing the structural damping. The maintenance track rail of the bridge girder also does some good for suppressing the VIV as long as the track rail is located at the appropriate place.

  13. 电力铁塔攀爬机器人的步态分析%Gait Analysis for Electricity Pylon Climbing Robot

    Institute of Scientific and Technical Information of China (English)

    曹志华; 陆小龙; 赵世平; 王蕾; 梁恩志; 刘晓宇

    2011-01-01

    为了提高电力系统的自动化水平,减轻电力工人在检修高压输电系统时的劳动强度,同时保障其人身安全,提出并设计了一种可以攀爬电力铁塔的5自由度关节式机器人,给出了机器人的CAD模型,分析了其在铁塔两种位置攀爬过渡的能力.根据机器人机构特征,提出、分析和比较了蠕虫式和扭转式攀爬步态.蠕虫式攀爬步态即机器人本体的两连杆之间角度周期变化,两爪交替前进;扭转式攀爬步态即机器人本体不动,爪部回转关节旋转180°使得机器人整体扭转半周.在机械系统动力学仿真软件ADAMS环境下,对机器人采用这两种步态在铁塔主材表面、横担侧面和上表面3种方位攀爬情况进行了仿真,计算和分析了不同情况下机器人各关节转矩和系统能耗,得出最适合铁塔各种方位的攀爬步态:在横担上攀爬时应采用能耗较小的扭转式步态,但是在主材表面攀爬时两种步态能耗接近,需考虑障碍类型选取合适的步态.仿真结果为机器人的攀爬步态规划及控制策略提供了依据,同时样机试验结果也验证了两种攀爬步态的可行性.%A 5-DOF articulated robot capable of climbing electricity pylons, is proposed to improve the automation capabilities of power system, reduce the labor intensity of workers and guarantee their safety in the maintenance of high-voltage transmission system. The CAD model for this robot is established, and the feasibility transiting between two positions in any orientations is verified The worm gait and turning gait are analyzed and compared In the worm gait the angle of the two linkages changes cyclically and two claws go forward alternately, and the body keeps still while the rotary joint rotates 180° to reverse the robot by semicycle in turning gait The joint torque and energy consumption of the robot when it climbs in various orientations including the main surface, side and upper surface of

  14. Shake Table Test of Cable-stayed Bridge Pylon Subjected to Longitudinal Ground Motions%斜拉桥桥塔纵桥向振动台试验研究

    Institute of Scientific and Technical Information of China (English)

    嵇冬冰; 段昕智; 徐艳; 李建中

    2013-01-01

    为了解强震作用下我国斜拉桥桥塔的抗震性能以及震害现象,通过调研确定典型斜拉桥原型,对其H型混凝土桥塔进行纵桥向振动台试验研究.基于斜拉桥的动力特点及振型分析方法进行桥塔模型的简化设计、制作和安装,输入不同类型及不同强度的地震波,对桥塔模型进行了振动台试验.结果表明:相比一般的Elcentro波和Chichi地震波,相同加速度峰值地震输入下,场地人工波激起桥塔的地震反应最剧烈,且随着地震动输入的不断加强,桥塔下塔柱、中塔柱靠近下横梁部位先后不同程度地出现了裂缝开展延伸现象,其中塔底向上30 cm区域内损伤较明显,存在多条贯通裂缝,塔底截面最外侧钢筋屈服,模型整体刚度有明显下降趋势,但桥塔抗震性能依然表现良好.%In order to understand the behavior and possible earthquake induced damages of cable-stayed bridges,based on the dynamic characteristics of the bridge,a simplified H shape pylon is designed,constructed and then tested on a shake table subjected to monotonously increased intensities of selected ground motions.Compared with the other two records,the site specific ground motion caused more severe shaking on the pylon model even at the same PGAs,and with the increase intensity of the input,the cracks induced were mainly in horizontal direction,first appearing in the bottom of the pylon,and then in lower column and middle column area near the lower strut.Especially in the area 30 cm above the column bottom,several through cracks appeared and the outmost longitudinal bar yielded,and the integral stiffness of the model tended to decrease,but the pylon model still behaves quite good under a sequence of earthquake excitations.

  15. Research on the Solution to Interference between Slat and Pylon of Transport Aircraft%运输机缝翼与挂架干涉解决方法研究

    Institute of Scientific and Technical Information of China (English)

    梁欣杰; 李明华; 孟涛

    2015-01-01

    Several proposals were studied from engineering standpoint to solve the problem of interference between slat and pylon of transport aircraft. Through analyzing the characteristics of each solution and the scope of application, some methods to solve the interference between slat and pylon were proposed for a reference. The methods of solutions can be lfexibly selected for high wing monoplanes according to different feature of the aircraft. But it is appropriate to disconnect the slat for low wing monoplanes.%为解决运输机缝翼与挂架的干涉,从工程设计角度出发,研究了几种解决缝翼与挂架干涉的方案。通过对每种解决方案的特点、适用范围进行分析和研究,给出解决缝翼与挂架干涉问题的参考方法。对于上单翼飞机可以依据自身情况灵活选取解决方案,而下单翼飞机更适合将缝翼断开解决缝翼与挂架的干涉。

  16. 马鞍山三塔悬索桥抗震性能研究%Research of Seismic Performance of Ma'anshan Three-pylon Suspension Bridge

    Institute of Scientific and Technical Information of China (English)

    王胜斌; 朱宇; 李建中

    2009-01-01

    According to the structural importance of Ma' anshan three-pylon suspension bridge, a seismic fortification criterion under two kinds of earthquake action probability level was determined and the corresponding target of seismic performance was brought out based on the design of the bridge. Ground motion parameters at the site of the bridge were obtained from the seismic risk analysis report, and the seismic response analysis of the bridge was undergone accordingly by means of the seismic response spectnun method and the nonlinear seismic time-history dynamic method to study the dynamic character and response under earthquake action. The optimization measures of the bridge seismic performance were determined based on the analytical result. It is concluded that the bridge seismic response under earthquake action can be decreased and the capability-demand ratio can be increased by using reasonable hydraulic damper to enhance the seismic performance and safety of the bridge.%以马鞍山三塔悬索桥的工程设计为背景,根据大桥结构的重要性确定了桥梁在两种概率水平的地震作用下的设防标准,并提出了相应的性能目标.根据桥址处地震危险性分析研究报告所给定的地震动数据对大桥进行反应谱分析和非线性动力时程分析,研究该桥的动力特性和地震反应特点,根据分析结果研究确定优化桥梁的抗震性能措施.经过计算分析比较得出,通过加设合理的液压阻尼装置可以减小结构在地震作用下的结构响应,提高全桥结构的能力需求比,增强了该桥的抗震性能水平,有利于桥梁结构在地震中的安全.

  17. 斜拉桥索塔锚固区前壁竖向拉-压杆模型%Vertical STM in Facade Wall of Pylon Anchorage Zone of Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    陶齐宇; 刘扬

    2011-01-01

    To the tendon anchorage system in the wall of box pylon of cable-stayed bridge, the facade wall of cable-anchored pylon was researched using strut-and-tie model ( STM). According to the optimization principle of STM, the STM of single anchor was established by means of force method. On the basis of the STM of single anchor, the STM in the facade wall was preliminary built. The expression of internal force in ties about z, the vertical distance between the tie T3 and node 1, was established. Using topology optimization result (T2 = 0) and Cardan Formula, the value of z was determined, the STM in the facade wall was comprehensively solved. Thus, the distribution of compressive and tensile stresses in the facade wall under the action of vertical component of cable force was accurately reflected. Finally, through researching the pylon of Yibin Yangzte River Bridge, the parameter α3 =23.3° was proposed, and the STM in the facade wall was simplified. It has better precision and can be used to determine tendon specification in the anchorage zone of box pylon.%对斜拉桥箱形截面索塔塔壁预应力锚固体系,采用拉-压杆模型方法对拉索直接锚固的塔柱前壁进行研究.以力法为手段,依据拉-压杆模型的优化原理,确立了体内单锚的拉-压杆模型.以单锚拉-压杆模型为基础,初步构建前壁的拉-压杆模型.取z为拉杆(T3)与结点(1)间的竖向距离,采用力法建立以z为函数的拉杆内力的表达式,利用拓扑优化成果(T2=0)和卡尔丹公式,确定z的数值,自下而上全面解答了前壁的拉-压杆模型,从而准确反映在拉索竖向分力作用下前壁拉、压应力的分布状况.最后,通过对宜宾长江大桥索塔的实例研究,提出α3= 23.3°,简化了前壁拉-压杆模型,且具有较好的工程精度,可用于确定索塔锚固区的预应力筋的规格.

  18. 荆岳长江公路大桥索塔锚固钢锚梁结构体系分析%Analysis of Steel Anchor Beam Structural System of Anchorage in Pylon of Jingyue Changjiang River Highway Bridge

    Institute of Scientific and Technical Information of China (English)

    张家元; 丁望星; 朱世峰

    2015-01-01

    荆岳长江公路大桥主桥为主跨816 m的双塔不对称混合梁斜拉桥,在成桥状态下,索塔锚固采用两端固定的钢锚梁结构体系。为研究钢锚梁平衡斜拉索索力的作用,验证超静定结构体系钢锚梁的合理性,采用ANSYS软件建立索塔锚固区有限元模型,分析钢锚梁施工过程中2种不同的支承体系方案,并通过足尺模型试验研究钢锚梁对斜拉索索力的分配比例。结果表明:斜拉索初张时采用边跨固定、中跨滑动,斜拉索张拉后两端固定结构体系的钢锚梁承担了斜拉索索力水平分力的83.7%,钢锚梁与塔壁对索力水平分力的分配比例为8∶2,该体系能够发挥钢锚梁平衡斜拉索索力的作用,且结构可靠度高。%The main bridge of Jingyue Changjiang River Highway Bridge is a asymmetric span hybrid girder cable‐stayed bridge with double pylons and with a main span of 816 m .The anchor‐age in a pylon of the bridge in completion state is of the steel anchor beam structural system with its two ends being fixed .To study the function of the anchor beam balancing the stay cable forces and to verify the rationality of the anchor beam of the statically indeterminate structural system , the software ANSYS was used to set up the finite element model for the anchorage in the pylon , 2 different support schemes adopted for construction of the anchor beam were analyzed and the ra‐tios of the stay cable forces distributed by the anchor beam were studied by means of the full‐scale model tests .The results of the study show that the anchor beam using the structural system with its side span end being fixed ,its central span end being slide at the time of initial tensioning of the stay cables and with its two ends being fixed after tensioning of the stay cables can bear 83 .7%horizontal component of the stay cable forces and the ratio of the horizontal component distributed by the anchor beam and pylon wall

  19. 异型钢箱混凝土索塔锚固区空间力学行为研究%Spatial Mechanical Behavior Research of Cable-pylon Anchorage Zone of Steel Box Concrete Tower

    Institute of Scientific and Technical Information of China (English)

    党栋; 贺拴海; 赵煜; 李世安

    2012-01-01

    In order to grasp the force performance and stress distribution of shaped pylon steel anchor box under the action of the cable tension, with a main span of 555 m length of three towers cable-stayed and self-anchored suspension combined system bridge as the engineering background, through the ANSYS APDL command stream parametric programming, the different finite element models of pylon steel anchor box is established by the spatial solid element and shell element, the mechanical properties of cable-pylon anchorage zone were studied under the most unfavorable load combination, considering the stress state and distribution characteristics of steel anchor box under different orthodontic force. The results showed that;under the most unfavorable combination of loads, the stress was concentrated at the position of the anchor plate and pressure plate using the initial strain mode; the calculation results of solid element and shell element were consistent by uniform loading mode, which could reflect the real stress state of steel anchor box, but the shell element corner contact area prone to stress calculation distortion. The results provide the basis for the design and have some design reference value for the design of the same type bridge.%为了掌握异型索塔钢锚箱在索力作用下的受力性能和应力分布,以某主跨555 m 长的三塔斜拉-自锚式悬索组合体系桥为工程背景,通过 ANSYS 中 APDL 命令流参数化编程,分别采用空间实体单元与壳单元建立了不同的索塔钢锚箱有限元模型,对索塔锚固区在最不利荷载组合作用下的受力性能进行了研究,并考虑了在不同加力方式下钢锚箱应力状态和分布特点.结果表明:在最不利荷载组合作用下,采用初应变加力方式,在锚垫板与承压板位置处应力较集中;采用均布力加载方式下,实体单元与壳单元计算结果较为吻合,能真实反映钢锚箱受力状态,但壳单元角点接触部位易出现应

  20. 电力铁塔攀爬机器人直线推杆机构设计与分析%Design and analysis of linear rod units for electricity pylons climbing robot

    Institute of Scientific and Technical Information of China (English)

    王蕾; 陆小龙; 赵世平; 曹志华; 刘晓宇; 梁恩志

    2012-01-01

    面向输电系统检测及维护作业的自动化,提出并设计了一种可以在电力铁塔表面自由移动的五自由度双臂关节式攀爬机器人,以期代替人工完成危险的高空攀爬检测作业任务.该电力铁塔攀爬机器人机构紧凑,左右机构对称,创新采用直线推杆机构实现两臂张合功能,此机构可良好支撑机器人双臂,相比传统关节设计采用的大转矩电机直驱方式,大幅度降低了对驱动电机的转矩要求.建立了机构CAD模型.进行了静力学分析,并在动力学仿真软件Adams软件环境下进行仿真.通过和电机直驱关节方法比较,分析和仿真结果均表明采用直线推杆机构可减小驱动电机转矩.样机试验结果表明电力铁塔攀爬机器人系统的设计组成原理合理,系统方案成功可靠.%For the automation of power transmission inspection and maintenance, a dual-arm articulated robot which can climb electricity pylons flexibly is proposed to perform dangerous aerial climbing detection work.The symmetrical and compact mechanism structure of the robot is developed with 2 grippers and 5-DOF,which audaciously adopts the linear rod units ,which may support the dual arms well,to realize griping and loosing motion, thus the torque requirement for driving motor is substantially lessened comparing to the traditional joints design which is drived by motor with large torque directly. Then a CAD model of the linear rod units is proposedAnd statics analysis and simulation using Adams software are put forword. Comparing to the traditional method drived by motor directly,the analysis and simulation results confirm that the design can reduce the torque of the motor.Prototype Experiments demonstrate that the design principle of the electricity pylons climbing robot is reasonable, and that the system are stable.

  1. 发动机吊挂与机翼连接接头强度分析与试验%Strength Analysis and Test on Connecting Joints between Aero Engine Pylon and Wing

    Institute of Scientific and Technical Information of China (English)

    孙滨; 林鸿志; 谭伟; 薛彩军

    2012-01-01

    The connecting joints between aircraft pylon and wing which are mainly used for transferring loads from aero engine are critical parts of aircraft structure and strength design. In order to analyze the joint strength as well as stress and strain distribution accurately, a static test system is established, and a finite element mod- eling method for the connecting joints is studied. Detailed finite element model is built based on the joint loads obtaining from the overall finite element model, and two serious load cases for the joints are analyzed. Compari- son of computing results and test results demonstrates that the finite element modeling method of joint strength is reasonable, which is of an application and reference value for the joint design between aero engine pylon and wing.%飞机吊挂与机翼连接接头主要用于传递来自动力装置的载荷,是飞机结构强度设计的关键件。为了精确分析吊挂与机翼连接接头强度及应力应变分布规律,设计了一套接头强度静力试验系统,研究了接头强度有限元建模方法。以总体有限元分析得到吊挂与机翼连接接头载荷为基础,建立了接头的细节有限元模型,分析了对接头强度影响较为严重的两种工况。有限元分析结果与试验结果对比,验证了接头强度有限元建模方法合理,对民机发动机吊挂与机翼接头设计具有应用参考价值。

  2. 翼/短舱/吊架气动特性及其动力影响数值研究%Numerical simulation of wing/nacelle/pylon aerodynamic characteristics and their changes under powered condition

    Institute of Scientific and Technical Information of China (English)

    李强; 汪明生

    2012-01-01

    Based on DLR-F6 model, the wing-nacelle_pylon (W-N-P) configuration dy- namic characteristics were calculated by computational fluid dynamics (CFD) method under through flow condition and powered condition respectively. The results show that the inter- ference configuration passage shock wave and nacelle vortex would increase nacelle overall drag and reduce wing lift. The resistance would he lower under power condition comr~aro with that ~mdo~- ~, k ~1~_%应用计算流体动力学(CFD)数值模拟方法对DLR-F6模型分别在通流及动力条件下翼/短舱/吊架(W-N-P)组合体部分的气动干扰特性进行研究.结果表明:组合体相互干扰引起的干扰通道附增激波及短舱后部逆压导致的涡流增加了短舱外罩阻力,降低了机翼升力;动力条件较通流条件,F6短舱外罩阻力降低,机翼升阻力特性在零度攻角时有所提高.

  3. Research on the Dumbbell Industry Integration Strategy of Mechanical Effect of Double Pylon Cable-stayed Bridge%“哑铃式”产业一体化战略集群与链式效应研究--基于双塔斜拉桥物理力学效应视角

    Institute of Scientific and Technical Information of China (English)

    刘永; 王达政; 张素珍

    2014-01-01

    Based on double pylon cable -stayed bridge physical mechanics effect ,this paper analyzes the in-tegration of the industry value chain cluster effect , the chain effect , the double pylon cable -stayed bridge physical and mechanical principle .It discusses the dumbbell industry integrated strategic model which high-lights the mechanical effect of double pylon cable -stayed bridge in constructing regional industry value chain---the cluster effect of the vertical gravity and the level of tension chain effect .It also explains that the "dumbbell industry integration strategy"model plays a research effect and far -reaching strategy role in balanced and powerfully driving rapid structural transformation and development of regional industrial econo-my.It has great reference to handling the relationship between the government and the market .%文章基于双塔斜拉桥物理力学效应视角,分析了产业价值链的集群效应、链式效应与双塔斜拉桥物理力学原理的融合,探讨了“哑铃式”产业一体化战略在区域产业价值链构筑中所彰显的双塔斜拉桥力学效应---垂直重力的集群效应与水平张力的链式效应,诠释了“哑铃式”产业一体化战略模型均衡有力拉动区域产业经济结构快速转型发展的效用与处理好政府与市场的关系有着深远战略指导意义。

  4. Transonic Aerodynamic Characteristics of a 45 deg Swept Wing Fuselage Model with a Finned and Unfinned Body Pylon Mounted Beneath the Fuselage or Wing, Including Measurements of Body Loads

    Science.gov (United States)

    Wornom, Dewey E.

    1959-01-01

    An investigation of a model of a standard size body in combination with a representative 45 deg swept-wing-fuselage model has been conducted in the Langley 8-foot transonic pressure tunnel over a Mach number range from 0.80 to 1.43. The body, with a fineness ratio of 8.5, was tested with and without fins, and was pylon-mounted beneath the fuselage or wing. Force measurements were obtained on the wing-fuselage model with and without the body, for an angle-of-attack range from -2 deg to approximately 12 deg and an angle-of-sideslip range from -8 deg to 8 deg. In addition, body loads were measured over the same angle-of-attack and angle-of-sideslip range. The Reynolds number for the investigation, based on the wing mean aerodynamic chord, varied from 1.85 x 10(exp 6) to 2.85 x 10(exp 6). The addition of the body beneath the fuselage or the wing increased the drag coefficient of the complete model over the Mach number range tested. On the basis of the drag increase per body, the under-fuselage position was the more favorable. Furthermore, the bodies tended to increase the lateral stability of the complete model. The variation of body loads with angle of attack for the unfinned bodies was generally small and linear over the Mach number range tested with the addition of fins causing large increases in the rates of change of normal-force coefficient and nose-down pitching-moment coefficient. The variation of body side-force coefficient with sideslip for the unfinned body beneath the fuselage was at least twice as large as the variation of this load for the unfinned body beneath the wing. The addition of fins to the body beneath either the fuselage or the wing approximately doubled the rate of change of body side-force coefficient with sideslip. Furthermore, the variation of body side-force coefficient with sideslip for the body beneath the wing was at least twice as large as the variation of this load with angle of attack.

  5. X-38 on B-52 Wing Pylon

    Science.gov (United States)

    1997-01-01

    A unique, close-up view of the X-38 (Crew Return Vehicle) under the wing of NASA's B-52 mothership prior to launch of the lifting-body research vehicle. The photo was taken from the observation window of the B-52 bomber as it banked in flight. The X-38 Crew Return Vehicle (CRV) research project is designed to develop the technology for a prototype emergency crew return vehicle or lifeboat for the International Space Station.

  6. Decoupler pylon: wing/store flutter suppressor

    Science.gov (United States)

    Reed, W. H., III (Inventor)

    1982-01-01

    A device for suspending a store from a support such as an aircraft wing and more specifically for increasing the flutter speed of an aircraft flying with attached store and reducing the sensitivity of flutter to changes in the pitch inertia and center of gravity location of the store is described. It comprises softspring where the store pitch mode is decoupled from support modes and a low frequency active control mechanism which maintains store alignment. A pneumatic suspension system both isolates the store in pitch and, under conditions of changing mean load, aligns the store with the wing to which it is attached.

  7. Hypermixer Pylon Fuel Injection for Scramjet Combustors

    Science.gov (United States)

    2008-09-11

    Characteristics and Thrust of Jets from Asymmetric Nozzles,” AIAA Paper 96-0200, Jan. 1996. 25Haimovitch, Y., Gartenberg, E., Roberts , A., and Northam, G...Control Using Streamwise Vortices,” AIAA Paper 1998-3271, Jul. 1998. 43Sunami, T., Magre, P., Bresson , A., Grisch, F., Orain, M., and Kodera, M

  8. 14 CFR 29.549 - Fuselage and rotor pylon structures.

    Science.gov (United States)

    2010-01-01

    ... flight conditions, must be considered. (c) Each engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (d) (e) If approval for the use of 21/2-minute OEI power is requested, each engine mount...

  9. 安庆长江铁路大桥3号墩围堰锚碇系统设计与施工%Design and Construction of Mooring System for Cofferdam of Pylon Pier No.3 of Anqing Changjiang River Railway Bridge

    Institute of Scientific and Technical Information of China (English)

    刘爱林; 农代培

    2011-01-01

    The bored pile foundation of pylon pier No. 3 of Anqing Changjiang River Railway Bridge was constructed with the circular double-wall steel boxed cofferdam. To realize the accurate positioning and construction safety of the cofferdam, through comparison of the different schemes, it was decided that the cofferdam would be positioned by the mooring system from the front and rear positioning barges without utilizing guiding barge. The types and numbers of the mooring anchors, the mooring ropes and positioning barges were determined according to the calculation of the total tensile force of the main anchors and the force of each anchor after sinking thecofferdam in place. In the design, the problem of steering and reeling of the large diameter mooring ropes was tackled by the tie points on the sides of the cofferdam and by the one-way or multi-way rolling fairleaders set at the top of the cofferdam. The side anchors were heaved by the winches installed on the anchor weighing platforms on the front and rear positioning barges and at the top of the cofferdam and the anchors could be therefore cast, weighed and changed. The side anchors on the shore and ground anchors were embedded in the excavated pits and the anchors under water were cast by the 240 t barge. The mooring ropes were timely tied, untied, tightened and the anchors were adjusted in pace of sinking of the cofferdam to finally complete the construction of the mooring system.%安庆长江铁路大桥3号桥塔墩钻孔桩基础采用圆形双壁钢套箱围堰施工.为实现围堰的精确定位和施工安全,经方案比较采用无导向船的前、后定位船锚碇系统定位方案,锚型与数量、锚绳及定位船通过计算围堰下沉到位后主锚总拉力及各锚碇受力确定.设计中通过在围堰侧面的边锚拉结点及围堰顶面设置单向或多向转动的辊轴式马口解决大直径锚绳转向和收放难题;通过在前、后定位船和围堰顶的收锚平台上安装

  10. CFD Wing/Pylon/Finned Store Mutual Interference Wind Tunnel Experiment

    Science.gov (United States)

    1991-02-01

    Ejector Location: 5.73 ft aft of store nose Aft Ejector Force: 9,600 lb, constant Ejector Stroke Length: 0.33 ft 33 7abie 3. i D and Run Numher...0 ~ ~~ 0-e tfo~ qm, N O -Omm4t cmf O 0~ ~ na N w N-W C.) ~ l C’W fmr - i-f 0fO M - to -Wf W! ! oot 0-mf O(i- 3O to~ (0c’ 0C4 -~~~ U! V!f Wfll V!~f V!if

  11. Transonic solutions of a wing/pylon/finned store using hybrid domain decomposition

    Science.gov (United States)

    Newman, James C., III; Baysal, Oktay

    1992-01-01

    Transonic Euler calculations about a complex multicomponent configuration are presented. The 3D Euler equations are solved utilizing an upwind-biased, alternating direction implicit, approximately factored, multigrid algorithm. Computational results are compared to experimental data of the finned store in a carriage position.

  12. 14 CFR 27.549 - Fuselage, landing gear, and rotor pylon structures.

    Science.gov (United States)

    2010-01-01

    ... engine mount and adjacent fuselage structure must be designed to withstand the loads occurring under accelerated flight and landing conditions, including engine torque. (Secs. 604, 605, 72 Stat. 778, 49...

  13. Characterization of clay-modified thermoset polymers under various environmental conditions for the use in high-voltage power pylons

    DEFF Research Database (Denmark)

    Kliem, Mathias; Høgsberg, Jan Becker; Wang, Qian

    2017-01-01

    , the morphology was found to be of exfoliated structure mainly. Static, uniaxial tensile tests showed that the addition of nanoclay to thermoset polymers led to a beneficial effect on the stiffness, whereas the tensile strength and ductility significantly decreased. When exposed to different environmental...

  14. The Effect of Bracket Base Pylon Orientation on the Shear Bond Strength of the ODP ANCHOR-LOCK Bracket Pad

    Science.gov (United States)

    2013-06-06

    directly to enamel without the need for additional bonding agents and surface treatments (Millet and McCabe, 1996). The primary mechanism for adhesion is...the adhesive surface than enamel would have during shear force application. The shapes and orientation of the brackets were not identical. Minor...that occurs while removing orthodontic adhesive with carbide burs is only 7.4 um, great care must be taken to avoid excessive damage to the enamel

  15. Analysis of Wing Pylon Connection%民用飞机翼下吊挂连接方式分析

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    民用飞机翼下吊挂是飞机结构中的重要组成部分,连接着飞机的机翼和发动机,是民用飞机的主要承力件,飞机飞行过程中吊挂受载复杂且对飞机的安全有重要的影响,本文主要分析了吊挂的连接方式,列举了波音、空客等公司常用的吊挂结构以及其连接特点,对吊挂设计需要考虑的方面进行了简单的阐述.

  16. An experimental investigation of nacelle-pylon installation on an unswept wing at subsonic and transonic speeds

    Science.gov (United States)

    Carlson, J. R.; Compton, W. B., III

    1984-01-01

    A wind tunnel investigation was conducted to determine the aerodynamic interference associated with the installation of a long duct, flow-through nacelle on a straight unswept untapered supercritical wing. Experimental data was obtained for the verification of computational prediction techniques. The model was tested in the 16-Foot Transonic Tunnel at Mach numbers from 0.20 to 0.875 and at angles of attack from about 0 deg to 5 deg. The results of the investigation show that strong viscous and compressibility effects are present at the transonic Mach numbers. Numerical comparisons show that linear theory is adequate for subsonic Mach number flow prediction, but is inadequate for prediction of the extreme flow conditions that exist at the transonic Mach numbers.

  17. Anti-slip security assessment between main cable and saddle of the middle pylon under extreme vehicle loads

    Institute of Scientific and Technical Information of China (English)

    Cui Jia; Ruan Xin; Zhou Xiaoyi

    2011-01-01

    The traffic condition of Taizhou Yangtze River Bridge is obtained to a certain extent, according to the traffic investigation nearby Taizhou Bridge. The statistical characteristics of the traffic conditions are acquired by statistical analysis. Simulation of the extreme vehicle loads and the sensitive analysis of load parameters are carried out based on these data complemented, which would guide the determination of the frictional coefficient between the main cables and the saddle.

  18. World War II Memorial Learning Activities.

    Science.gov (United States)

    Tennessee State Dept. of Education, Nashville.

    These learning activities can help students get the most out of a visit to the Tennessee World War II Memorial, a group of ten pylons located in Nashville (Tennessee). Each pylon contains informational text about the events of World War II. The ten pylons are listed as: (1) "Pylon E-1--Terror: America Enters the War against Fascism, June…

  19. 76 FR 39248 - Airworthiness Directives; Airbus Model A300 B4-600, B4-600R, and F4-600R Series Airplanes, and...

    Science.gov (United States)

    2011-07-06

    .... * * * * * * The pipe drains the double wall of the wing-to-pylon junction in the event of fuel leakage. After... under the pylon lower spar. The pipe drains the double wall of the wing-to-pylon junction in the event... wing-to-pylon junction in the event of fuel leakage. After investigation, it was concluded that...

  20. Design and construction of scour protection for deep-water group pile foundation structures of two pylons in the Sutong Bridge project

    Institute of Scientific and Technical Information of China (English)

    He Ping; Guan Yijun; Zhang Xiongwen; Zhang Qun; Zhou Jianhua

    2009-01-01

    Sutong Bridge, as a world-record cable-stayed bridge with its main span exceeding 1 000 m constructed in Yangtze River estuary region in China, is located at a site with complicated hydrologic conditions and poor geotechnical conditions and therefore, scour protection will be a decisive factor for ensuring smooth and successful construction of this bridge. This paper, starting from structural description of deep-water group pile foundation, analyzes impact to the bridge safety introduced by scour and its protection and further presents different solutions of scour protection for foundation structures of this bridge.

  1. Numerical Complex Flowfield Simulation of Wing/body/Pylon/Nacelle Configuration%机翼-机身-挂架-短舱复杂流场数值模拟

    Institute of Scientific and Technical Information of China (English)

    高正红; 黄江涛

    2009-01-01

    本文采用分区搭接网格技术,对机翼/机身/挂架/短舱复杂组合体进行网格分布,通过分析计算网格对结果的影响,探讨了网格的划分.基于Roe的近似黎曼解的方法,采用S-A湍流模型,通过求解N-S方程,对该组合体外流场/发动机短舱内流场进行一体化数值模拟,与相应风洞实验数据进行了比较与分析,取得了与实验数据较为吻合的结果.与无发动机短舱的组合体的气动特性进行比较,分析了短舱对翼身组合体的气动干扰.

  2. Theoretical prediction of interference loading on aircraft stores: Part I - Subsonic speeds

    Science.gov (United States)

    Fox, C. H., Jr.; Fernandes, F.

    1973-01-01

    Computer program is developed for theoretically predicting loading on pylon-mounted stores in subsonic compressible flow. Linear theory predicts flow field produced by aircraft wing, nose, inlet, and pylons. Program was written in FORTRAN IV for CDC 6000 computer.

  3. VFT insulation coordination study of a 400 kV GIS

    DEFF Research Database (Denmark)

    Olason, Daniel; Ebdrup, Thomas; Bak, Claus Leth

    2014-01-01

    .dk) is in the process of constructing a new gas insulated substation (GIS) in Revsing. As a part of this process, new Eagle pylons will replace some of the existing Donau pylons. The new Eagle type pylon is meant to reduce the visual impact of transmission lines. The reliability of the substation in Revsing is of great...

  4. 75 FR 76926 - Airworthiness Directives; Airbus Model A300 B4-600, B4-600R, and F4-600R Series Airplanes, and...

    Science.gov (United States)

    2010-12-10

    ... engine 1. * * * * * * The pipe drains the double wall of the wing-to-pylon junction in the event of fuel.... The pipe drains the double wall of the wing-to-pylon junction in the event of fuel leakage. After... drains the double wall of the wing-to-pylon junction in the event of fuel leakage. After...

  5. 75 FR 42592 - Airworthiness Directives; The Boeing Company Model 767-200, -300, and -300F Series Airplanes...

    Science.gov (United States)

    2010-07-22

    ... Corrosion--Inspection and Replacement. 767-54-0061 2 November 23, 1999 Nacelles/Pylons--Wing-to-Strut Attach... Strut and Wing Structure Modification. 767-54-0081 1 February 7, 2002. Nacelles/Pylons--General Electric...-54A0094 2 February 7, 2002. Nacelles/Pylons--Strut--to--Wing Attachment--Diagonal Brace Inspection/...

  6. 78 FR 65204 - Airworthiness Directives; BAE Systems (Operations) Limited Airplanes

    Science.gov (United States)

    2013-10-31

    ... in the engine pylon separating from the wing, with consequent damage to the airplane and reduced... report of a cracked pick-up bracket of the forward outboard pylon of the number 1 engine due to stress corrosion. This AD requires repetitive inspections and, depending on findings, repair of the pylon...

  7. 76 FR 15870 - Airworthiness Directives; Airbus Model A310 Series Airplanes, and Airbus Model A300 B4-600, B4...

    Science.gov (United States)

    2011-03-22

    ... reported several cases of wire damages at the pylon/ wing interface. Analysis revealed that wires damages... the pylon/ wing interface. Analysis revealed that wires damages are due to installation quality issue..., this AD requires the modification of the electrical installation in the pylon/wing interface to...

  8. 78 FR 46301 - Airworthiness Directives; BAE Systems (Operations) Limited Airplanes

    Science.gov (United States)

    2013-07-31

    ..., which could result in the engine pylon separating from the wing, with consequent damage to the airplane... in the engine pylon separating from the wing, with consequent damage to the airplane and reduced... of a cracked pick- up bracket of the forward outboard pylon of the number 1 engine due to...

  9. Improvement on the Fastening System of Wing Pylon Attachment Upcover%某型飞机机翼吊挂接头上口盖紧固系统的改进

    Institute of Scientific and Technical Information of China (English)

    房延志; 介苏朋

    2008-01-01

    针对一个特定口盖紧固系统存在的松动问题,通过对故障的分析,提出了改进的技术方案,并经过理论分析和试验验证,确立了更改方案的合理性和可用性,并在飞机上得以实施.

  10. Aerodynamic optimization design of wing-body-nacelle-pylon configuration%机翼-机身-短舱-挂架外形气动优化设计方法

    Institute of Scientific and Technical Information of China (English)

    左英桃; 傅林; 高正红; 邵其林; 白俊强

    2013-01-01

    采用基于径向基函数的无限插值方法进行了复杂外形的动网格生成,并针对其存在的可能导致壁面附近出现负体积与网格质量下降的问题,提出对不与物面直接相连的边的位移采用径向基函数插值,对与物面相连的边的位移进行线性插值获得位移量的方法解决该问题.采用无限插值方法建立了一种简单有效的物面相贯线处理方法.利用离散共轭方法计算目标函数梯度,对DLR-F6机翼-机身-短舱-挂架外形的机翼和短舱进行了几何外形参数化与气动外形优化设计.结果表明:考虑短舱安装方式的优化设计较不考虑短舱安装方式的优化设计可降低大约0.000 1的阻力系数.通过全机优化设计,将全机阻力系数降低了0.001 53.

  11. 武汉天兴洲公铁两用桥主塔爬模设计及应用%Design and Application of Climbing Slipform Formwork in Pylon Tower of Wuhan Tianxingzhou Yangtze River Highway-railway Bridge

    Institute of Scientific and Technical Information of China (English)

    宁智刚

    2011-01-01

    武汉天兴洲公铁两用桥主塔模板施工采用液压自爬模体系,打破了传统的施工工艺,对施工环境、提高施工工效、安全环保等都有所改善.针对该工程主塔模板施工,施工脚手架采用液压自爬模系统配合木工字梁模板体系,并对爬模体系进行了优化和设计.此外,阐述了模板系统组成及液压自爬架组成,详细介绍了爬模施工方案以及安全规定.体现了液压自爬模及木梁胶合板模板体系用于异型混凝土结构的优越性.%Hydraulic climbing slipform system is used with main tower formwork construction of Wuhan Tianxingzhou Yangtze river highway-railway bridge, the traditional construction technology is changed. The construction environment, construction efficiency, safety and environmental protection is all improved. Based on the construction, construction scaffolding is used with hydraulic climbing slipform system combined with wood H beam formwork system, and auto-climbing formwork system is optimized and designed. In addition, formwork system composition and hydraulic climbing slipform system are expounded. Construction scheme of climbing slipform and safety regulations are introduced in detail. The fact shows that it is reasonable that hydraulic climbing slipform system and timber beam plywood formwork system are used in non-standard concrete structure.

  12. 78 FR 41039 - 36(b)(1) Arms Sales Notification

    Science.gov (United States)

    2013-07-09

    ... Distribution Systems, and 32 SUU-63 pylons. The proposed program support includes software test and integration... contractor technical and logistics support services, and other related elements of logistics support. (iv...), Multifunctional Information Distribution Systems, and 32 SUU-63 pylons. The proposed program support includes...

  13. 77 FR 16143 - Airworthiness Directives; The Boeing Company Airplanes

    Science.gov (United States)

    2012-03-20

    ... away from the pylon on the outboard side of the pylon will not result in an improvement, since the wing... leaks from the wing leading edge area onto the engine exhaust area. This AD requires modifying the fluid drain path in the leading edge area of the wing. We are issuing this AD to prevent flammable fluid...

  14. 75 FR 50867 - Airworthiness Directives; Airbus Model A330-223, -321, -322, and -323 Airplanes

    Science.gov (United States)

    2010-08-18

    ... (PW) forward (FWD) engine mount pylon bolts. * * * * * Dual-bolt fractures could lead to inability for mount assembly to sustain loads which may lead to an engine mount failure and consequently to engine... one of the Pratt & Whitney (PW) forward (FWD) engine mount pylon bolts. Investigation has...

  15. 77 FR 58970 - Special Conditions: Embraer S.A. Model EMB-550 Airplanes, Sudden Engine Stoppage

    Science.gov (United States)

    2012-09-25

    ... conditions are proposed: 1. For turbine-engine installations, the engine mounts, pylons, and adjacent... acceleration of the engine. 2. For auxiliary power unit (APU) installations, the APU mounts and adjacent... be multiplied by a factor of 1.0 when applied to engine mounts and pylons, and multiplied by a...

  16. 78 FR 41684 - Special Conditions: Embraer S.A. Model EMB-550 Airplanes, Sudden Engine Stoppage

    Science.gov (United States)

    2013-07-11

    ...-engine installations, the engine mounts, pylons, and adjacent supporting airframe structure must be... are to be multiplied by a factor of 1.0 when applied to engine mounts and pylons, and multiplied by a..., Sudden Engine Stoppage AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final...

  17. 78 FR 67323 - Special Conditions: Airbus, Model A350-900 Series Airplane; Transient Engine Failure Loads

    Science.gov (United States)

    2013-11-12

    ...: 1. For turbine engine installations, the engine mounts, pylons, and adjacent supporting airframe... multiplied by a factor of 1.0 when applied to engine mounts and pylons and multiplied by a factor of 1.25...; Transient Engine Failure Loads AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice...

  18. Unique characteristics of Pb in soil contaminated by red lead anti-corrosion paint

    NARCIS (Netherlands)

    Brokbartold, M.; Temminghoff, E.J.M.; Weng, L.; Marschner, B.

    2013-01-01

    Red lead (Pb3O4) has been extensively used in the past in anti-corrosion paints for the protection of steel constructions such as electricity pylons or bridges. Until recently, little has been known about the behavior of these Pb compounds in soils. Therefore, three pylon soils and six red lead anti

  19. Air Vehicle Integration and Technology Research (AVIATR). Task Order 0003: Condition-Based Maintenance Plus Structural Integrity (CBM+SI) Demonstration (September 2012 to March 2013)

    Science.gov (United States)

    2013-03-01

    release; distribution unlimited. CP IAT Description 3 Yr All Verif 53A/B 19 Lower Skin Near Large Pylon Hole 4 12  54B/C N/T Inner Wing Lwr Skin at...Aft Pylon Hole  55 /124B 21 Main Spar Lower Flange 11 236  56 62 Main Spar Lower Flange 4 4  57B 2 Outer Wing rear Spar Lower Flange 2 103... Wing Trail Edge Closure Spar Web 139 N/T Inner Wing Lwr Skin Inbd Trail Edge Fast at Pylon 140 / 1 N/T Inner Wing Inboard Lower Skin Trailing

  20. 商用飞机翼吊短舱安装位置对吊挂系统布置空间影响研究%Impact of Wing-Mounted Nacelle Position on the Pylon System-Arrangement Space for Commercial Aircrafts

    Institute of Scientific and Technical Information of China (English)

    赵海涛

    2016-01-01

    商用飞机翼吊短舱安装位置是飞机总体布局的重要参数之一,会对飞机性能产生重要影响;吊挂是连接短舱/发动机与机翼的结构部件,其内部机载系统的布置需求也会在一定程度上影响飞机性能.本文讨论了控制短舱位置参数的变化对吊挂系统布置空间的影响,并得出相关结论,为短舱位置和吊挂系统布置工作提供支持.

  1. 倾转旋翼机前飞时机翼/短舱/旋翼耦合系统气弹稳定性分析%Aeroelastic stability of wing/pylon/rotor coupled system for tiltrotor aircraft in forward flight

    Institute of Scientific and Technical Information of China (English)

    杨朝敏; 夏品奇

    2011-01-01

    倾转旋翼机是一种具有普通直升机垂直起降与空中悬停能力,又兼备螺旋桨式固定翼飞机高速远程巡航能力的新型飞行器.由于旋翼与机翼之间复杂的动力学耦合关系,在前飞状态下系统的动力学稳定性随着前飞速度的提高而降低,从而限制了倾转旋翼机飞行速度的提高.针对机翼具有弹性弯扭耦合特性的倾转旋翼机系统,建立了其前飞时机翼/短舱/旋翼耦合系统的气弹稳定性分析模型.利用Boeing试验模型的参数对倾转旋翼机前飞状态下的气弹稳定性进行计算,分析了机翼弹性弯扭耦合特性对气弹稳定性的影响.结果表明,机翼向上弯曲引起前缘低头的弹性弯扭耦合特性可以显著提高机翼垂向模态的失稳速度,而机翼向前弯曲引起前缘低头的弹性弯扭耦合特性则对提升机翼弦向模态的失稳速度非常有利.

  2. 76 FR 24351 - Airworthiness Directives; Airbus Model A340-200 and -300 Series Airplanes

    Science.gov (United States)

    2011-05-02

    ... economic impact, positive or negative, on a substantial number of small entities under the criteria of the... A340-200/-300 pre- modification 49203 (reinforcements of pylon primary structure for enhanced...

  3. 78 FR 49662 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A Airplanes

    Science.gov (United States)

    2013-08-15

    ... INDUSTRIES S.p.A Model P-180 airplanes, all serial numbers, certificated in any category. (d) Subject Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 54; Nacelles/Pylons...

  4. 78 FR 58967 - Airworthiness Directives; ATR-GIE Avions de Transport Régional Airplanes

    Science.gov (United States)

    2013-09-25

    ...- time inspection of the affected area [between the nacelle lower fairing and the underbox wing for...) Subject Air Transport Association (ATA) of America Code 54, Nacelles/ pylons. (e) Reason This AD...

  5. 78 FR 14007 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Electrical/Electronic Equipment Bay...

    Science.gov (United States)

    2013-03-04

    ... configuration with a low wing and T-tail empennage. The primary structure is metal with composite empennage and... fuselage pylons. Each engine produces approximately 6,540 pounds of thrust for normal takeoff. The...

  6. 78 FR 49655 - Special Conditions: Embraer, S.A., Model EMB-550 Airplane; Side-Facing Seats; Installation of...

    Science.gov (United States)

    2013-08-15

    ... conventional configuration with low wing and T-tail empennage. The primary structure is metal with composite... mounted on aft fuselage pylons. Each engine produces approximately 6,540 pounds (lbs) of thrust for...

  7. NASA and Army Collaboration on Unmanned Systems Presentation to the Association for Unmanned Vehicle Systems International (AUVSI)

    Science.gov (United States)

    Fernandez, Ken

    2008-01-01

    This viewgraph presentation describes the collaborative effort of NASA and the US Army on unmanned systems. The contents include: 1) Robotic/Autonomous Systems Architecture Development; 2) Synergy In Robotics/Autonomous Systems Development; 3) Surface Mobility Systems: Lunar Pylon Network Project; 4) Lunar Pylon Network Enables Multiple Vehicle Operations & Logistics; 5) Surface Mobility Systems: MARCbot IV-N Project Overview; 6) Autonomous Logistics Support Demonstration; and 7) Lunar Network Demonstration and Collaborative Effort.

  8. Supersonic Combustion Ramjet Research

    Science.gov (United States)

    2012-08-01

    release by the USAF 88th Air Base Wing (88 ABW) Public Affairs Office (PAO) and is available to the general public, including foreign nationals...Figure 12: Layout for Radiography at the Advanced Photon Source (7-BM Beamline). ........... 16 Figure 13: µ- Pylon Injector Schematic (Left) and...Spanwise Equivalence Ratio Image from Raman Scattering (Right) for Pylon with h = 6.3, W = 2.5, l = 11, and d = 1.6 mm. .................. 17 Figure 14

  9. In-flight piv for cror flight test demonstration

    OpenAIRE

    Pommier-Budinger, Valérie; Bury, Yannick; Michon, Guilhem; Napias, Gael

    2016-01-01

    Designing innovative solutions for future aircraft is one the concerns of aeronautical engineers. Among the studied technologies, Counter Rotating Open Rotor (CROR) propeller technologies are appearing as a promising, though highly challenging, alternative solution to Ultra High Bypass Ratio (UHBR) engines. Amongst these challenges, the interaction of the wake of the CROR engine pylon with the counter rotating blades, positioned downstream of the pylon (pusher configuration), are responsible ...

  10. Minimising mortality in endangered raptors due to power lines: the importance of spatial aggregation to optimize the application of mitigation measures.

    Directory of Open Access Journals (Sweden)

    Francisco Guil

    Full Text Available Electrocution by power lines is one of the main causes of non-natural mortality in birds of prey. In an area in central Spain, we surveyed 6304 pylons from 333 power lines to determine electrocution rates, environmental and design factors that may influence electrocution and the efficacy of mitigation measures used to minimise electrocution cases. A total of 952 electrocuted raptors, representing 14 different species, were observed. Electrocuted raptors were concentrated in certain areas and the environmental factors associated with increased electrocution events were: greater numbers of prey animals; greater vegetation cover; and shorter distance to roads. The structural elements associated with electrocutions were shorter strings of insulators, one or more phases over the crossarm, cross-shaped design and pylon function. Of the 952 carcasses found, 148 were eagles, including golden eagle (Aquila chrysaetos, Spanish imperial eagle (Aquila adalberti and Bonelli's eagle (Aquila fasciata. Electrocuted eagles were clustered in smaller areas than other electrocuted raptors. The factors associated with increased eagle electrocution events were: pylons function, shorter strings of insulators, higher slopes surrounding the pylon, and more numerous potential prey animals. Pylons with increased string of insulators had lower raptor electrocution rates than unimproved pylons, although this technique was unsuccessful for eagles. Pylons with cable insulation showed higher electrocution rates than unimproved pylons, both for raptors and eagles, despite this is the most widely used and recommended mitigation measure in several countries. To optimize the application of mitigation measures, our results recommend the substitution of pin-type insulators to suspended ones and elongating the strings of insulators.

  11. Minimising mortality in endangered raptors due to power lines: the importance of spatial aggregation to optimize the application of mitigation measures.

    Science.gov (United States)

    Guil, Francisco; Fernández-Olalla, Mariana; Moreno-Opo, Rubén; Mosqueda, Ignacio; Gómez, María Elena; Aranda, Antonio; Arredondo, Angel; Guzmán, José; Oria, Javier; González, Luis Mariano; Margalida, Antoni

    2011-01-01

    Electrocution by power lines is one of the main causes of non-natural mortality in birds of prey. In an area in central Spain, we surveyed 6304 pylons from 333 power lines to determine electrocution rates, environmental and design factors that may influence electrocution and the efficacy of mitigation measures used to minimise electrocution cases. A total of 952 electrocuted raptors, representing 14 different species, were observed. Electrocuted raptors were concentrated in certain areas and the environmental factors associated with increased electrocution events were: greater numbers of prey animals; greater vegetation cover; and shorter distance to roads. The structural elements associated with electrocutions were shorter strings of insulators, one or more phases over the crossarm, cross-shaped design and pylon function. Of the 952 carcasses found, 148 were eagles, including golden eagle (Aquila chrysaetos), Spanish imperial eagle (Aquila adalberti) and Bonelli's eagle (Aquila fasciata). Electrocuted eagles were clustered in smaller areas than other electrocuted raptors. The factors associated with increased eagle electrocution events were: pylons function, shorter strings of insulators, higher slopes surrounding the pylon, and more numerous potential prey animals. Pylons with increased string of insulators had lower raptor electrocution rates than unimproved pylons, although this technique was unsuccessful for eagles. Pylons with cable insulation showed higher electrocution rates than unimproved pylons, both for raptors and eagles, despite this is the most widely used and recommended mitigation measure in several countries. To optimize the application of mitigation measures, our results recommend the substitution of pin-type insulators to suspended ones and elongating the strings of insulators.

  12. Minimising Mortality in Endangered Raptors Due to Power Lines: The Importance of Spatial Aggregation to Optimize the Application of Mitigation Measures

    Science.gov (United States)

    Guil, Francisco; Fernández-Olalla, Mariana; Moreno-Opo, Rubén; Mosqueda, Ignacio; Gómez, María Elena; Aranda, Antonio; Arredondo, Ángel; Guzmán, José; Oria, Javier; González, Luis Mariano; Margalida, Antoni

    2011-01-01

    Electrocution by power lines is one of the main causes of non-natural mortality in birds of prey. In an area in central Spain, we surveyed 6304 pylons from 333 power lines to determine electrocution rates, environmental and design factors that may influence electrocution and the efficacy of mitigation measures used to minimise electrocution cases. A total of 952 electrocuted raptors, representing 14 different species, were observed. Electrocuted raptors were concentrated in certain areas and the environmental factors associated with increased electrocution events were: greater numbers of prey animals; greater vegetation cover; and shorter distance to roads. The structural elements associated with electrocutions were shorter strings of insulators, one or more phases over the crossarm, cross-shaped design and pylon function. Of the 952 carcasses found, 148 were eagles, including golden eagle (Aquila chrysaetos), Spanish imperial eagle (Aquila adalberti) and Bonelli's eagle (Aquila fasciata). Electrocuted eagles were clustered in smaller areas than other electrocuted raptors. The factors associated with increased eagle electrocution events were: pylons function, shorter strings of insulators, higher slopes surrounding the pylon, and more numerous potential prey animals. Pylons with increased string of insulators had lower raptor electrocution rates than unimproved pylons, although this technique was unsuccessful for eagles. Pylons with cable insulation showed higher electrocution rates than unimproved pylons, both for raptors and eagles, despite this is the most widely used and recommended mitigation measure in several countries. To optimize the application of mitigation measures, our results recommend the substitution of pin-type insulators to suspended ones and elongating the strings of insulators. PMID:22140549

  13. Multiple smart weapons employment mechanism

    Energy Technology Data Exchange (ETDEWEB)

    McGlynn, M.P.; Meiklejohn, W.D.

    1993-07-20

    A digital communications armament network adaptor is described for carrying multiple smart weapons on a single wing pylon station of an aircraft, comprising: an aircraft having a weapons controller configured in compliance with MIL-STD 1553; multiple wing-mounted pylons on said aircraft, each providing a weapons station with communications and ejection and release mechanisms electrically connected to said controller for the airborne launch of smart weapons; a multiple ejector rack affixed to at least one pylon, said rack holding a plurality of smart weapons; and an electronic digital network connected between the controller and said rack-mounted smart weapons, said network located in said rack and including circuitry which receives coded digital communications from said controller and selectively rebroadcasts said communications to one of said smart weapons on said rack designated by said coded communications, thereby controlling all required functions of said designated smart weapon.

  14. Directivity and trends of noise generated by a propeller in a wake

    Science.gov (United States)

    Block, P. J. W.; Gentry, C. L., Jr.

    1986-09-01

    An experimental study of the effects on far-field propeller noise of a pylon wake interaction was conducted with a scale model of a single-rotation propeller in a low-speed anechoic wind tunnel. A detailed mapping of the noise directivity was obtained at 10 test conditions covering a wide range of propeller power landings at several subsonic tip speeds. Two types of noise penalties were investigated-pulser and spacing. The pusher noise penalty is the difference in the average overall sound pressure level, OASPL, for pusher and tractor installations. (In a pusher installation, the propeller disk is downstream of a pylon or another aerodynamic surface.) The spacing noise penalty is the difference in the average OASPL for different distances between the pylon trailing edge and the propeller. The variations of these noise penalties with axial, or flyover, angle theta and circumferential angle phi are presented, and the trends in these noise penalties with tip Mach number and power loading are given for selected values of theta and phi. The circumferential directivity of the noise from a pusher installation showed that the addition noise due to the interaction of the pylon wake with the propeller had a broad peak over a wide range of circumferential angles approximately perpendicular to the pylon with a sharp minimum 90 deg. to the pylon for the majority of cases tested. The variation of the pusher noise penalty with theta had a minimum occurring near the propeller plane and maximum values of as much as 20 dB occurring toward the propeller axes. The magnitude of the pusher noise penalty generally decreased as propeller tip Mach number or power loading was increased.

  15. A State of the Art Overview

    DEFF Research Database (Denmark)

    Jahangiri, Tohid; Bak, Claus Leth; Silva, Filipe Miguel Faria da;

    2015-01-01

    The first EHV composite cross-arms have been used since late 1990's in Switzerland. It was the first step to the compaction of towers sizes. Since then, significant advances have been made in composite cross-arms technology while the lattice construction technique has not been seriously challenged....... The proposed new fully composite pylon has a novel cross-arm in the form of uni-body insulator in order to reduce the tower height. So far, there is no theoretical analysis and technical standards for fully composite pylons. In this paper, two major challenges facing in the design of a fully composite...

  16. Design of Cable-Stayed Bridge of Caofeidian Industry Zone Bridge No.1%曹妃甸工业区1号桥斜拉桥设计

    Institute of Scientific and Technical Information of China (English)

    陈亮; 卢永成; 周伟翔; 邵长宇

    2011-01-01

    The Caofeidian Industry Zone Bridge No. 1 is composed of navigable span bridge, non-navigable span bridges and approach bridges and is located in the cold and strong earthquake region in the northern part of China. A summarized account of the design of the navigable span bridge of the bridge is presented herewith. In accordance with the construction conditions and landscape requirements, the navigable span bridge is designed as a single pylon and single cable plane cable-stayed bridge with span arrangement 2 X 138 m, the pylon is the column pylon in shape of boat sail. The anchorage zone in the pylon is the steel anchor box exposed outside the pylon. The main girder is the steel and concrete composite girder having three cells and a single box. The stay cables are made up of φ7 mm galvanized parallel steel wires and the foundation of the pylon pier is the group pile foundation. The research of seismic resistance of the bridge show that for a major single pylon cable-stayed bridge located in the strong earthquake region, the rigid fixity system of pylon, girder and pier should be possibly avoided in order to reduce seismic response of the bridge structure.%曹妃甸工业区1号桥位于北方寒冷强震区,由通航孔桥、非通航孔桥及引桥组成,综述该桥通航孔桥设计.根据建设条件及景观要求,通航孔桥为跨径2×138 m独塔单索面斜拉桥;桥塔为独柱形,造型为船帆式;索塔锚固区采用外露式钢锚箱方案;主梁采用单箱三室钢-混凝土箱形结合梁;斜拉索采用φ7 mm镀锌平行钢丝;桥塔墩采用群桩基础.抗震性能研究表明,强震区大型独塔斜拉桥应尽量避免采用塔、梁、墩固结体系,以减小桥梁结构的地震响应.

  17. Modal Based Fatigue Monitoring of Steel Structures

    DEFF Research Database (Denmark)

    Graugaard-Jensen, J.; Brincker, Rune; Hjelm, H. P.;

    2005-01-01

    compared with direct strain gauge measurements and it appears that the difference between the strains measured by strain gauges and the strains estimated by the presented technique is quite small. Looking at the fatigue of the lattice pylon it appears that the estimated damage is significantly smaller than...... by applying the mode shapes of the calibrated Finite Element model and strains are obtained using the shape functions for the actual elements. The technique has been applied on a model frame structure in the laboratory and on a wind loaded lattice pylon structure. In both cases the estimated stresses has been...

  18. 78 FR 6195 - Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection...

    Science.gov (United States)

    2013-01-30

    ... jet airplanes designed for corporate flight, fractional, charter, and private owner operations. The... turbofan engines mounted on aft fuselage pylons. Each engine produces approximately 6,540 pounds of thrust... function into the engine of the Model EMB-550 airplane. It has a full authority digital electronic...

  19. 75 FR 74663 - Airworthiness Directives; The Boeing Company Model 747-400 and -400D Series Airplanes

    Science.gov (United States)

    2010-12-01

    ... corrective actions, if necessary; and modification of the electrical power feeder cable installation... proposing this AD to detect and correct chafing of the main fuel feed tube and the alternating current motor... drain line of the number two engine pylon. An investigation revealed that the alternating current...

  20. Pilot Milt Thompson and the M2-F2 Lifting Body

    Science.gov (United States)

    1966-01-01

    Jay L. King, Joseph D. Huxman and Orion D. Billeter assist NASA research pilot Milt Thompson (on the ladder) into the cockpit of the M2-F2 lifting body research aircraft at the NASA Flight Research Center (now the Dryden Flight Research Center). The M2-F2 is attached to a wing pylon under the wing of NASA's B-52 mothership.

  1. An Inquiry: Effectiveness of the Complex Empirical Mode Decomposition Method, the Hilbert-Huang Transform, and the Fast-Fourier Transform for Analysis of Dynamic Objects

    Science.gov (United States)

    2012-03-01

    52 Figure 4: Dihedral Spherical Corner Reflector , on Styrofoam pylon .............................. 53 Figure 5: The...Magnitude of Dihedral Corner Reflector ........................................... 82 Figure 14: CEMD Magnitude of Real-World Signal—IMF #3...s) Multivariate Empirical Mode Decomposition MEMD Radar - Cross Section RCS Rotational Invariant Complex Empirical Mode Decomposition RICEMD

  2. Illustrative Experiments of the Erosion of Sand and Accompanying Theoretical Considerations

    Science.gov (United States)

    Schneiderbauer, Simon

    2012-01-01

    Winds in desert regions form the well-known barchan dunes. Frequently, human settlements are threatened by the migration of these dunes. But why do these dunes move? And how is dune migration in deserts connected to scour development in the vicinity of pylons in river beds or to snow cornices in alpine regions? This paper introduces the topic of…

  3. A comparison of models for measurable deterioration: an application to coating on steel structures

    NARCIS (Netherlands)

    R.P. Nicolai (Robin); R. Dekker (Rommert); J.M. van Noortwijk (Jan)

    2006-01-01

    textabstractSteel structures like bridges, tanks and pylons are exposed to outdoor weathering conditions. In order to prevent them from corrosion they are protected by organic coating systems. This paper focuses on modelling the deterioration of the organic coating layer that protects steel structur

  4. Maintenance Models for Systems subject to Measurable Deterioration

    NARCIS (Netherlands)

    R.P. Nicolai (Robin)

    2008-01-01

    textabstractComplex engineering systems such as bridges, roads, flood defence structures, and power pylons play an important role in our society. Unfortunately such systems are subject to deterioration, meaning that in course of time their condition falls from higher to lower, and possibly even to u

  5. Noise Simulations of the High-Lift Common Research Model

    Science.gov (United States)

    Lockard, David P.; Choudhari, Meelan M.; Vatsa, Veer N.; O'Connell, Matthew D.; Duda, Benjamin; Fares, Ehab

    2017-01-01

    The PowerFLOW(TradeMark) code has been used to perform numerical simulations of the high-lift version of the Common Research Model (HL-CRM) that will be used for experimental testing of airframe noise. Time-averaged surface pressure results from PowerFLOW(TradeMark) are found to be in reasonable agreement with those from steady-state computations using FUN3D. Surface pressure fluctuations are highest around the slat break and nacelle/pylon region, and synthetic array beamforming results also indicate that this region is the dominant noise source on the model. The gap between the slat and pylon on the HL-CRM is not realistic for modern aircraft, and most nacelles include a chine that is absent in the baseline model. To account for those effects, additional simulations were completed with a chine and with the slat extended into the pylon. The case with the chine was nearly identical to the baseline, and the slat extension resulted in higher surface pressure fluctuations but slightly reduced radiated noise. The full-span slat geometry without the nacelle/pylon was also simulated and found to be around 10 dB quieter than the baseline over almost the entire frequency range. The current simulations are still considered preliminary as changes in the radiated acoustics are still being observed with grid refinement, and additional simulations with finer grids are planned.

  6. 77 FR 73270 - Airworthiness Directives; Embraer S.A. Airplanes

    Science.gov (United States)

    2012-12-10

    ..., Doors; 53, Fuselage; 54, Nacelles/Pylons; 55, Stabilizers; 57, Wings; 71, Powerplant; and 78, Engine.... Compliance time TR 2-5, dated December 6, 2007...... Wing stub main box 57-01-002-0002 250 flight cycles...-16319 (75 FR 30277, June 1, 2010)). TR 2-5, dated December 6, 2007...... Wing stub spar 3--...

  7. 76 FR 62653 - Airworthiness Directives; Airbus Model A310 Series Airplanes

    Science.gov (United States)

    2011-10-11

    ... of chafing with the new routing of the wire bundle 2S in the RH wing pylon area to the generator wire... the fuel electrical circuit in the Right Hand (RH) wing must be modified in order to ensure better... electrical circuit in the right hand wing must be modified to ensure better segregation between fuel...

  8. 78 FR 22215 - Airworthiness Directives; The Boeing Company Airplanes

    Science.gov (United States)

    2013-04-15

    ... currently requires modification of the nacelle strut and wing structure; for certain airplanes, repetitive..., November 26, 1999)). AD 2004-12-07 requires modification of the nacelle strut and wing structure; and for... America Code 54, Nacelles/Pylons. (e) Unsafe Condition This AD was prompted by reports indicating that...

  9. 77 FR 21397 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2012-04-10

    ... bundle 2S in the RH wing pylon area to the generator wire bundle of engine 2. The modification of this... the fuel electrical circuit in the right-hand wing must be modified in order to ensure better... route 2S of the fuel electrical circuit in the Right Hand (RH) wing must be modified in order to...

  10. The Best Aircraft for Close Air Support in the Twenty First Century

    Science.gov (United States)

    2016-09-01

    and rescue, armed reconnaissance, airborne interdiction, civil support, disaster response, maritime patrol, and border security.34 Equipped with a...carrying capacity. With 11 pylons, it is the most configurable of the airframes and can be used in conjunction with triple ejector racks and dual

  11. 77 FR 28328 - Airworthiness Directives; Sikorsky Aircraft Corporation Helicopters

    Science.gov (United States)

    2012-05-14

    ... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation... time-in-service (TIS), within 25 hours TIS and thereafter at intervals not to exceed 10 hours TIS... TIS, within 12 months; For a T/R pylon with 1,500 through 3,749 hours TIS, within 24 months; and For...

  12. 14 CFR 21.93 - Classification of changes in type design.

    Science.gov (United States)

    2010-01-01

    ... engine and nacelle carriage external to the skin of the airplane (and return of the pylon or other external mount), or (iii) Time-limited engine and/or nacelle changes, where the change in type design... flight and is not part of an airframe or engine. An “acoustical change” does not include: (A) Addition...

  13. 78 FR 18925 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2013-03-28

    ... torque check of forward engine mount bolts, and replacement if necessary. We are proposing this AD to... unsafe condition for the specified products. The MCAI states: The forward mount engine pylon bolts, Part... series engines. However, the engine mount system is considered to be part of aeroplane...

  14. 76 FR 10213 - Special Conditions: Embraer Model EMB-135BJ (Legacy 650) Airplanes, Limit Engine Torque Loads for...

    Science.gov (United States)

    2011-02-24

    ... engine mounts, pylons and adjacent supporting airframe structure must be designed to withstand 1g level... developed from these conditions are to be multiplied by a factor of 1.0 when applied to engine mounts and... 650) Airplanes, Limit Engine Torque Loads for Sudden Engine Stoppage AGENCY: Federal...

  15. 78 FR 68352 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2013-11-14

    ... engine mount bolts, and replacement if necessary. We are issuing this AD to detect and correct loose or... an unsafe condition for the specified products. The MCAI states: The forward mount engine pylon bolts... PW4000 series engines. However, the engine mount system is considered to be part of...

  16. 78 FR 31851 - Harmonization of Airworthiness Standards-Gust and Maneuver Load Requirements

    Science.gov (United States)

    2013-05-28

    ... turbulence design loads criteria; revise the application of gust loads to engine mounts, high lift devices.... 25.362) We propose to revise the engine loads design requirements for engine mounts, auxiliary power unit mounts, engine pylons, and adjacent supporting airframe structures. The proposed amendment...

  17. 77 FR 54933 - Government-Owned Inventions, Available for Licensing

    Science.gov (United States)

    2012-09-06

    ... Active Vibration Control System for a Flexible Panel; NASA Case No.: LAR-17984-1: Elastically Deformable....: LAR-17833-1: Active Aircraft Pylon Noise Control System; NASA Case No.: LAR-17908-1: Photogrammetry...-1: Team Electronic Gameplay Combining Different Means of Control; NASA Case No.: LAR-18016-1...

  18. 21 CFR 890.3025 - Prosthetic and orthotic accessory.

    Science.gov (United States)

    2010-04-01

    ... intended for medical purposes to support, protect, or aid in the use of a cast, orthosis (brace), or prosthesis. Examples of prosthetic and orthotic accessories include the following: A pelvic support band and belt, a cast shoe, a cast bandage, a limb cover, a prosthesis alignment device, a postsurgical pylon,...

  19. Technology for long cable erection of a thousand-meter scale cable-stayed bridge

    Institute of Scientific and Technical Information of China (English)

    Rao Huarong; Deng Huibin

    2009-01-01

    In the background of the construction of Sutong Yangtze River Bridge (short as Sutong Bridge), the cable construction method and techniques of a thousand-meter scale cable-stayed bridge are introduced. Some key construction techniques, such as outspreading cable on deck, installing cable at pylon, pulling and fixing cable at the attachment with decks and cable PE sheath protection are discussed.

  20. Theoretical prediction of interference loading on aircraft stores: Part II - Supersonic speeds

    Science.gov (United States)

    Fox, C. H., Jr.; Fernandes, F.

    1973-01-01

    Linear theory is used, without two dimensional or slender body assumptions, to predict flow field produced by aircraft wing, nose, inlet, and pylons. Aircraft shock wave locations are predicted, and their effect on flow field is included through transformation of aircraft geometry. Program was written in FORTRAN IV for CDC 6400 computer.

  1. MF magnitude does not affect body condition, pro-oxidants and anti-oxidants in Eurasian kestrel (Falco tinnunculus) nestlings

    NARCIS (Netherlands)

    Costantini, David; Casagrande, Stefania; Dell'Omo, Giacomo

    2007-01-01

    Pylons of utility lines are commonly used by breeding birds as structures for supporting their nests. Nesting near power lines, however, exposes adult birds and their offspring to the electric and magnetic fields (EMFs) produced by the current. Therefore, we searched for possible relationships betwe

  2. Evaluating the release of a large store from the BAE Hawk Mk120

    CSIR Research Space (South Africa)

    Jamison, Kevin

    2010-11-01

    Full Text Available The analysis of the release of a large store from the outboard pylon of the BAE Hawk Mk120 is described as a case study. The process adopted to address this challenge included using both the ARUV panel code and the CFD-FASTRAN Navier...

  3. Warfighter Support: Improved Joint Oversight and Reporting on DOD’s Prepositioning Programs May Increase Efficiencies

    Science.gov (United States)

    2011-05-01

    tanks, missile launchers, pylons, ejector racks, and adapters,18 medical stocks, fuel, and Defense Logistics Agency-managed items such as rations...recommendations that balance limited resources against operational risk to the Director of Program Analysis and Evaluation, now referred to as the

  4. Fatigue of threaded rods in cable anchorages due to Vortex shedding

    NARCIS (Netherlands)

    Maljaars, J.; Snijder, H.H.

    2013-01-01

    The 'Hovenring' is a bicycle roundabout flyover built as a signature bridge with a central steel pylon carrying a circular bridge deck suspended through stay-cables. Shortly after installation of the bridge, the stay-cables turned out to vibrate in the wind due to vortex shedding. These vibrations h

  5. Prospective study of Helicobacter pylori antigens and gastric noncardia cancer risk in the Nutrition Intervention Trial cohort

    OpenAIRE

    Murphy, Gwen; Freedman, Neal D; Michel, Angelika; Fan, Jin-Hu; Taylor, Philip R.; Pawlita, Michael; Qiao, You-Lin; Zhang, Han; Yu, Kai; Abnet, Christian C.; DAWSEY, Sanford M.

    2015-01-01

    Helicobacter pylon (H. pylori) infection is the strongest known risk factor for gastric non-cardia adenocarcinoma (GNCA). We used multiplex serology to determine whether seropositivity to 15 H. pylori proteins is associated with the subsequent development of non-cardia gastric cancer in Linxian, China.

  6. Lichens in the rural landscape of the Warmia Plain

    Directory of Open Access Journals (Sweden)

    Rafał Szymczyk

    2013-12-01

    Full Text Available Lichens and lichenicolous fungi in the rural landscape of the Warmia Plain were studied. Lichen species were observed on old wooden fences, roadside trees, fruit trees, pylons, farm machinery, buildings and bridges. The analysed biota consists of 104 taxa with several noteworthy and rare lichens.

  7. Optimal Damping of Stays in Cable-Stayed Bridges for In-Plane Vibrations

    DEFF Research Database (Denmark)

    Jensen, C.N.; Nielsen, S.R.K.; Sørensen, John Dalsgaard

    2002-01-01

    Significant vibrations have been reported in stays of recently constructed cable stayed bridges. The vibrations appear as in-plane vibrations that may be caused by rain–wind- induced aeroelastic interaction or by resonance excitation of the cables from the motion of the pylons. The stays of moder...

  8. Design of Danyang Road Bridge in Heze City%菏泽市丹阳路大桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟

    2015-01-01

    菏泽市丹阳路大桥为(40+100+240+100+40) m 双塔中央单索面半飘浮体系混凝土斜拉桥。该桥塔、墩固结,主梁与塔、墩间设置横、竖向支座和纵向液压阻尼器;主梁采用单箱三室斜腹板截面,高3.6m。桥塔采用顺桥向人字形的独柱混凝土塔,高68.2m,单箱单室矩形空心截面。人字形塔柱穿过主梁,与墩身顺接,墩身采用十字形空心薄壁截面,矩形承台,布置33根φ2.0m钻孔灌注桩。辅助墩和交接墩均采用花瓶形双柱式框架墩,矩形承台,布置8根φ1.5m钻孔灌注桩。斜拉索采用φ7 mm镀锌高强平行钢丝束。采用MIDAS Civil 2006和SCDS平面程序对该桥进行计算分析,结果表明该桥各项检算均满足规范要求。%T he Danyang Road Bridge in Heze City is a semi‐floating system concrete cable‐stayed bridge with double pylons ,a central single cable plane and with span arrangement (40+100+240+100+40) m .T he pylons and piers of the bridge are rigidly fixed and in betw een the main girder and pylons and piers ,the lateral and vertical bearings and the longitudinal hydraulic damp‐ers are arranged .The cross section of the main girder is the section of triple‐cell single box with in‐clined webs and the girder is 3 .6 m in depth .In the longitudinal direction of the bridge ,a pylon is the single‐column concrete pylon in the shape of inverted Y ,is 68 .2 m in height and the cross sec‐tion of the pylon is the rectangular hollow section of single‐cell single box .The inverted Y‐shape pylon passes through the main girder and is smoothly fixed with the pylon pier .The cross section of the pylon pier is the crisscross hollow thin‐wall section and the pier stands on the rectangular pile cap under w hich 33 nos .of φ2 .0 m bored piles are arranged .T he auxiliary piers and boundary piers are all the vase‐shape double‐column frame piers and respectively stand on each rectangular

  9. Overall Design of Baitanhu Lake Bridge%白潭湖大桥总体设计

    Institute of Scientific and Technical Information of China (English)

    张全阳

    2014-01-01

    基于城市桥梁的景观要求,白潭湖大桥主桥采用纵向对称布置的(150+150) m混凝土独塔斜拉桥的设计方案。桥塔以拱为形态元素,采用椭圆形拱塔结构;主梁采用预应力混凝土单箱三室斜腹板箱梁,人行道置于斜拉索锚固区外侧;斜拉索采用扇形空间双索面布置,主梁上锚固采用混凝土齿块锚固形式,塔上锚固采用混凝土锚块+隔板的锚固形式;过渡墩采用花瓶形板式墩。桥塔采用爬模施工,桥塔横梁采用分节段浇筑,设置2 m合龙段;主梁采用分节段支架现浇施工,共分13个施工节段。有限元计算结果表明,结构受力满足规范要求。%Given the demands of landscape effect of city bridges ,the design scheme of a (150+150) m concrete single pylon cable-stayed bridge that is symmetrically arranged in the longitudinal direction is chosen for the main bridge of Baitanhu Lake Bridge .The pylon which is basically an arch is designed as an elliptic arched pylon structure .The main girder is the prestressed concrete three-cell single box structure with inclined webs .The sidewalk is arranged along the outer side of the anchorage zone of the stay cables . The stay cables are fanned out in spatial double cable planes ,which are anchored to the main girder via concrete teeth ,but anchored to the pylon with the assistance of concrete blocks and bulkheads .T he transitional piers are vase-shaped plate piers . The pylon is constructed by climbing formwork and the pylon cross beam is cast in segments with a 2 m long closure section .The main girder is cast in segments on scaffoldings and a total of 13 construction segments are made .The results of the finite element calculation indicate that the force conditions of the structure can meet the code requirements .

  10. Electric Field and Potential Distribution in a 420 kV Novel Unibody Composite Cross-Arm

    DEFF Research Database (Denmark)

    Jahangiri, Tohid; Bak, Claus Leth; Silva, Filipe Miguel Faria da

    2015-01-01

    The use of uni-body composite cross-arm in a fully composite-based pylon is a new concept for the next generation of overhead transmission lines. The cross-arm is stressed by phase-to-phase voltages except in two regions, which are stressed by phase-to-ground voltages caused by installation...... of shield wires. Due to a major difference between the novel cross-arm structure and traditional composite cross-arms, the electric field distribution in the uni-body composite cross-arm is of considerable interest. This paper presents and analyses the electric field distribution around and inside...... and potential distribution along the pylon is graphically depicted and the effectiveness of assigned shed profiles in controlling the power frequency stresses are investigated in the areas with high field intensities....

  11. Complex configuration analysis at transonic speeds

    Science.gov (United States)

    Boppe, C. W.; Aidala, P. V.

    1980-01-01

    Advanced performance requirements of new combat and transport aircraft together with design time constraints intensify the development and application of three dimensional computational analyses. A computational method which was developed for the specific purpose of providing an engineering analysis of complex aircraft configurations at transonic speeds. Particular attention is given to the recently incorporated wing viscous interaction and canard capabilities. The treatment of fuselage fairings, nacelles, and pylons is reviewed. The means for keeping computing resources at reasonable levels are identified. Three configurations were selected for correlations with experimental data. Taken together, the comparisons illustrate the full extent of current analysis capabilities. The configurations include: (1) a wing fuselage canard fighter; (2) a transport with fuselage fairings, four nacelles, four pylons; and (3) a space vehicle which includes an external fuel tank and rocket boosters (transonic launch configuration).

  12. Nonlinear analysis of green house systems

    Directory of Open Access Journals (Sweden)

    Ashraf Mohamed Mahmoud

    2012-12-01

    Full Text Available A numerical procedure based on energy minimization has been extended herein to analyze a system of two dimensional cable trusses called green houses. The joint displacements and member forces results are obtained and compared with a finite element computer program and previously published thesis. This study was done on three cases of span lengths. It was found that the effect of increasing the pylon height (H on the displacements and member forces is less than the case when reducing the value of (H. It was found also that the choice of the span length L = 16 m is more preferable than the others, because the rate of change of displacements and end forces was minimal compared with the others. It was also observed that when the number of spans is increased, the effect of the variation of the pylon height on the cable truss total weight will be vanished.

  13. Extended Aging Theories for Predictions of Safe Operational Life of Critical Airborne Structural Components

    Science.gov (United States)

    Ko, William L.; Chen, Tony

    2006-01-01

    The previously developed Ko closed-form aging theory has been reformulated into a more compact mathematical form for easier application. A new equivalent loading theory and empirical loading theories have also been developed and incorporated into the revised Ko aging theory for the prediction of a safe operational life of airborne failure-critical structural components. The new set of aging and loading theories were applied to predict the safe number of flights for the B-52B aircraft to carry a launch vehicle, the structural life of critical components consumed by load excursion to proof load value, and the ground-sitting life of B-52B pylon failure-critical structural components. A special life prediction method was developed for the preflight predictions of operational life of failure-critical structural components of the B-52H pylon system, for which no flight data are available.

  14. An Improved Method for Power-Line Reconstruction from Point Cloud Data

    Directory of Open Access Journals (Sweden)

    Bo Guo

    2016-01-01

    Full Text Available This paper presents a robust algorithm to reconstruct power-lines using ALS technology. Point cloud data are automatically classified into five target classes before reconstruction. In order to improve upon the defaults of only using the local shape properties of a single power-line span in traditional methods, the distribution properties of power-line group between two neighbor pylons and contextual information of related pylon objects are used to improve the reconstruction results. First, the distribution properties of power-line sets are detected using a similarity detection method. Based on the probability of neighbor points belonging to the same span, a RANSAC rule based algorithm is then introduced to reconstruct power-lines through two important advancements: reliable initial parameters fitting and efficient candidate sample detection. Our experiments indicate that the proposed method is effective for reconstruction of power-lines from complex scenarios.

  15. NASA/GE Collaboration on Open Rotors - High Speed Testing

    Science.gov (United States)

    VanZante, Dale E.

    2011-01-01

    A low-noise open rotor system is being tested in collaboration with General Electric and CFM International, a 50/50 joint company between Snecmaand GE. Candidate technologies for lower noise will be investigated as well as installation effects such as pylon integration. Current test status for the 8x6 SWT high speed testing is presented as well as future scheduled testing which includes the FAA/CLEEN test entry. The tunnel blockage and propeller thrust calibration configurations are shown.

  16. Light Helicopter Family Trade-Off Analysis. Volume 4. Appendix N

    Science.gov (United States)

    1985-05-15

    U) It should be noted that designing a tail pylon folding point into a composite fuselage creates significant structural problema due to...engine operating at this level is 30 minutes. However, after a (short) period of time at a less power setting, V( lRP ) may be used again. The exact...HELICOPTER -so -20 -10 IB +10 +20 ♦ao EFFCCNCYOt) Figure N-VI-25. V( lRP ) speed efficiency sumraary. N-VI-31 LHX

  17. Analysis of transonic aerodynamic interference in the wing-nacelle region for a generic transport aircraft

    OpenAIRE

    Soda, Ante; Voß, Ralph

    2005-01-01

    This paper presents results of a numerical investigation dealing with steady and unsteady aerodynamic wing-nacelle-pylon (WNP) interference effects. In the first part of the paper the design process of the generic WIONA (Wing with Oscillating Nacelle) geometry is described. It is shown that development of major interference effects in the channel between wing and nacelle strongly depends on geometrical parameters of the configuration. After the geometry definition, the steady viscous interfer...

  18. Swords & Plowshares: Modifications to the MLRS Family of Munitions

    Science.gov (United States)

    2013-04-01

    strike package, carrying lethal bombs instead of Delilahs on their wing pylons , loiters outside of enemy air defense threat rings and controls the...conditions preclude or prohibit the use of fixed wing aircraft or ships. In the four-quadrant configuration using existing munitions, the Universal...After their assigned Delilah missiles attack, the controlling aircraft, since it still has lethal munitions under its wings , can be re-tasked to

  19. Safety and Suitability for Service Assessment Testing for Aircraft Launched Munitions

    Science.gov (United States)

    2013-07-01

    aircraft since shock responses can be affected by local influences such as wing and fuselage bending modes, pylon interfaces, and structural damping...and unguided munitions deployed on fixed and rotary wing aircraft (manned or unmanned). The munitions covered by this JOTP include aircraft launched...attached to an aircraft (e.g., missile attached to a launcher on an aircraft wing ). 4. FACILITIES AND INSTRUMENTATION. 4.1 Facilities. All

  20. Numerical Wing/Store Interaction Analysis of a Parametric F16 Wing

    OpenAIRE

    Cattarius, Jens

    1999-01-01

    A new numerical methodology to examine fluid-structure interaction of a wing/pylon/store system has been developed. The aeroelastic equation of motion of the complete system is solved iteratively in the time domain using a two-entity numerical code comprised of ABAQUS/Standard and the Unsteady-Vortex-Lattice Method. Both codes communicate through an iterative handshake procedure during which displacements and air loads are updated. For each increment in time the force/displacement equilibriu...

  1. Overlapped Gridによる翼ナセル干渉の数値解析

    OpenAIRE

    TANI, Yasuhiro; Amano, Kanichi; 谷 泰寛; 天野 完一

    1994-01-01

    A numerical study was carried out on wing/nacelle interference for transonic transports. To reduce the interference drag, some shapes of small wings, Liplets, were designed. Liplet is a wing installed on both sides of the pylon just downstream of the upper part of the nacelle fan cowl trailing edge, to control the flow in the interference region. Three dimensional Euler calculation was carried out at transonic cruise condition. A flow analysis code using overlapped grid method was developed a...

  2. C-5M Super Galaxy Utilization with Joint Precision Airdrop System

    Science.gov (United States)

    2012-03-22

    General Electric CF6 engine (Knight, 2008). This engine upgrade, along with upgrades to pylons , auxiliary power units, aircraft skin, frame, landing...Table 2. C-5 Legacy vs. C-5M Comparison C-5 A/B* C-5M** Length 247.8 feet 247.8 feet T-Tail Height 65.1 feet 65.1 feet Wing Span 222.8 feet

  3. C-5 Reliability Enhancement and Re-engining Program (C-5 RERP)

    Science.gov (United States)

    2015-12-01

    Logistics ) C-5 RERP December 2015 SAR March 23, 2016 16:10:28 UNCLASSIFIED 4 Mr. Brian Townsend C-5 Division Mobility Directorate 2275 D Street...addition to new engines/pylons, C-5 RERP will provide upgrades to wing attachment fittings; new thrust reversers and auxiliary power units; upgrades...team successfully expedited delivery and fielding of updated C-5 software (Operational Flight Program version 3.5.2) and associated logistics support

  4. EXPLAINING POWER OVER THE INVESTEE - THE RIGHTS THAT GIVE THE POSSIBILITY TO DIRECTS THE INVESTEE`S RELEVANT ACTIVITIES

    Directory of Open Access Journals (Sweden)

    Adrian ŞTEFAN-DUICU

    2015-07-01

    Full Text Available The links created on all levels between the parent company and its subsidiaries have generated along time debates regarding the subterfugii to the regulations applicable in the audit activity in order to protect the above mentioned entities. Throughout this paper we will progressively describe the pylons that represent the foundation of the regulations subject to the audit activity in this organizational environment.

  5. Prepositioned Materiel and Equipment: DOD Would Benefit from Developing Strategic Guidance and Improving Joint Oversight

    Science.gov (United States)

    2012-09-20

    analysis by having two analysts independently compare the prepositioned materiel and equipment information in DOD’s fiscal year 2011 report with the 12...Source: GAO analysis . We assessed five of the elements as being addressed because the information provided in the report was responsive to the...report did not include Air Force munitions, auxiliary fuel tanks, missile launchers, pylons, ejector racks, and adapters, medical stocks, fuel, and

  6. Establishing a Common Phase Reference for Comparing Synthetic Data to RF Range Measurements

    Science.gov (United States)

    2010-05-01

    processes using Theodolite laser measurements. I. INTRODUCTION In order to accurately compare synthetic and measured data, a common phase...utilizing a Theodolite (Sokkia Total Station Set 230R). Reflective targets were placed on the front, back and side walls of the chamber and measured with...the Theodolite and used as reference points. A 31” square flat plate was mounted on the pylon rotator and “peaked” using the radar to establish a

  7. JPRS Report Soviet Union, Economic Affairs.

    Science.gov (United States)

    2007-11-02

    machine building situation, how- Vesuvius and powerful earthquakes like the recent one in ever, makes it impossible to speak about widescale Armenia...to Kiev. They were shipped by carrying layout for the fuselage and the central wing mounting them on the fuselage of an An-22, for which section was...determined right away: the to reach very high calculated stresses (37 to 39 kilograms high wing, six engines mounted on suspended pylons, the per square

  8. Optical measurements on overhead optical fiber cables for stresses and damage identification

    Science.gov (United States)

    Ravet, Fabien L.; Heens, Bernard; Daniaux, D.; Froidure, Jean-Christophe; Blondel, Michel; Dascotte, M.; Lots, P.

    1998-12-01

    This paper concerns the characterization of various trunks of an OPGW based network. No strong fiber aging has been observed but combined OTDR and PMD measurements have pointed out strong cable clamping at suspension pylon. Large local losses have been measured at both 1.55 micrometers and 1.6 micrometers and stress induced birefringent behavior have been experienced. PMD temporal evolution has also been studied. A correlation between temperature variation and PMD evolution has been observed.

  9. Comparison of overhead line lightning performance based on two different tower geometries

    DEFF Research Database (Denmark)

    Ebdrup, Thomas; Olason, Daniel; Bak, Claus Leth

    2014-01-01

    As a part of reinforcing the 400 kV transmission system in Jutland, Denmark, the Danish TSO is in the process of constructing a new gas insulated substation (GIS) in Revsing. This includes raising a new type of pylon, which will carry the new overhead lines to the GIS. The reliability of the subs......As a part of reinforcing the 400 kV transmission system in Jutland, Denmark, the Danish TSO is in the process of constructing a new gas insulated substation (GIS) in Revsing. This includes raising a new type of pylon, which will carry the new overhead lines to the GIS. The reliability...... of the substation and transmission line is of great importance as it is a part of the 400 kV backbone between Sweden, Norway, Germany and the offshore wind farms in Horns Rev, Denmark. The new Eagle pylon has been designed with the focus of minimizing the visual impacted of overhead lines. A detailed lightning...

  10. Comparative simulation of wind park design and siting in Algeria

    Energy Technology Data Exchange (ETDEWEB)

    Youcef Ettoumi, Fatiha; Adane, Abd El Hamid; Benzaoui, Mohamed Lassaad; Bouzergui, Nabila [Faculty of Electronics and Computer Science, Telecommunication Department, Laboratory of Image Processing and Radiation, University of Science and Technology of Algiers (U.S.T.H.B.), P.O. Box 32, El Alia, Bab Ezzouar 16111, Algiers DZ (Algeria)

    2008-10-15

    In this paper, five typical regions of Algeria where wind is strong enough are selected. These regions usually intended for traditional agriculture are, centred around the towns of Guelma, El Oued, Tindouf, Touggourt and Tamanrasset. To make wind energy conversion available as an alternative energy source for the populations living in such countries, nine types of small and medium wind turbines constructed by American and European manufacturers are studied for their suitability. To account for the wind variations with height, four possible heights of the pylon holding the turbines are considered: 10, 20, 40 and 60 m. In each of the five locations and at each pylon height, wind energy converted by the turbines, is cumulated over the year and computed. Depending on the site and their size, most of these turbines are found to produce about 1000-10,000 MWh of electricity per year at 60 m of altitude and can easily satisfy the electricity need in irrigation and its household applications in rustic and arid regions. A quick glance of the results of the above computation shows that the choice of pylons of 20 m height yields a trade-off between the production of electrical energy and the requirements of economy. Owing to the sporadic wind variations, wind energy conversion systems can only be used as an auxiliary source. In particular, these systems can advantageously be coupled to stand-alone photovoltaic conversion systems in remote locations or connected to the electric mains in urban zones. (author)

  11. Whirl Flutter Stability and Its Influence on the Design of the Distributed Electric Propeller Aircraft X- 57

    Science.gov (United States)

    Hoover, Christian B.; Shen, Jinwei; Kreshock, Andrew R.; Stanford, Bret K.; Piatak, David J.; Heeg, Jennifer

    2017-01-01

    This paper studies the whirl flutter stability of the NASA experimental electric propulsion aircraft designated the X-57 Maxwell. whirl flutter stability is studied at two flight conditions: sea level at 2700 RPM to represent take-off and landing and 8000 feet at 2250 RPM to represent cruise. Two multibody dynamics analyses are used: CAMRAD II and Dymore. The CAMRAD II model is a semi-span X-57 model with a modal representation for the wing/pylon system. The Dymore model is a semi-span wing with a propeller composed of beam elements for the wing/pylon system that airloads can be applied to. The two multibody dynamics analyses were verified by comparing structural properties between each other and the NASTRAN analysis. For whirl flutter, three design revisions of the wing and pylon mount system are studied. The predicted frequencies and damping ratio of the wing modes show good agreements between the two analyses. Dymore tended to predict a slightly lower damping ratio as velocity increased for all three dynamic modes presented. Whirl flutter for the semi-span model was not present up to 500 knots for the latest design, well above the operating range of the X-57.

  12. Wired: impacts of increasing power line use by a growing bird population

    Science.gov (United States)

    Moreira, Francisco; Encarnação, Vitor; Rosa, Gonçalo; Gilbert, Nathalie; Infante, Samuel; Costa, Julieta; D’Amico, Marcello; Martins, Ricardo C.; Catry, Inês

    2017-02-01

    Power lines are increasingly widespread across many regions of the planet. Although these linear infrastructures are known for their negative impacts on bird populations, through collision and electrocution, some species take advantage of electricity pylons for nesting. In this case, estimation of the net impact of these infrastructures at the population level requires an assessment of trade-offs between positive and negative impacts. We compiled historical information (1958–2014) of the Portuguese white stork Ciconia ciconia population to analyze long-term changes in numbers, distribution range and use of nesting structures. White stork population size increased 660% up to 12000 breeding pairs between 1984 and 2014. In the same period, the proportion of nests on electricity pylons increased from 1% to 25%, likely facilitated by the 60% increase in the length of the very high tension power line grid (holding the majority of the nests) in the stork’s distribution range. No differences in breeding success were registered for storks nesting on electricity pylons versus other structures, but a high risk of mortality by collision and electrocution with power lines was estimated. We discuss the implications of this behavioral change, and of the management responses by power line companies, both for stork populations and for managers.

  13. Effects of Bifurcations on Aft-Fan Engine Nacelle Noise

    Science.gov (United States)

    Nark, Douglas M.; Farassat, Fereidoun; Pope, D. Stuart; Vatsa, Veer N.

    2004-01-01

    Aft-fan engine nacelle noise is a significant factor in the increasingly important issue of aircraft community noise. The ability to predict such noise within complex duct geometries is a valuable tool in studying possible noise attenuation methods. A recent example of code development for such predictions is the ducted fan noise propagation and radiation code CDUCT-LaRC. This work focuses on predicting the effects of geometry changes (i.e. bifurcations, pylons) on aft fan noise propagation. Beginning with simplified geometries, calculations show that bifurcations lead to scattering of acoustic energy into higher order modes. In addition, when circumferential mode number and the number of bifurcations are properly commensurate, bifurcations increase the relative importance of the plane wave mode near the exhaust plane of the bypass duct. This is particularly evident when the bypass duct surfaces include acoustic treatment. Calculations involving more complex geometries further illustrate that bifurcations and pylons clearly affect modal content, in both propagation and radiation calculations. Additionally, results show that consideration of acoustic radiation results may provide further insight into acoustic treatment effectiveness for situations in which modal decomposition may not be straightforward. The ability of CDUCT-LaRC to handle complex (non-axisymmetric) multi-block geometries, as well as axially and circumferentially segmented liners, allows investigation into the effects of geometric elements (bifurcations, pylons).

  14. Transonic Drag Prediction on a DLR-F6 Transport Configuration Using Unstructured Grid Solvers

    Science.gov (United States)

    Lee-Rausch, E. M.; Frink, N. T.; Mavriplis, D. J.; Rausch, R. D.; Milholen, W. E.

    2004-01-01

    A second international AIAA Drag Prediction Workshop (DPW-II) was organized and held in Orlando Florida on June 21-22, 2003. The primary purpose was to inves- tigate the code-to-code uncertainty. address the sensitivity of the drag prediction to grid size and quantify the uncertainty in predicting nacelle/pylon drag increments at a transonic cruise condition. This paper presents an in-depth analysis of the DPW-II computational results from three state-of-the-art unstructured grid Navier-Stokes flow solvers exercised on similar families of tetrahedral grids. The flow solvers are USM3D - a tetrahedral cell-centered upwind solver. FUN3D - a tetrahedral node-centered upwind solver, and NSU3D - a general element node-centered central-differenced solver. For the wingbody, the total drag predicted for a constant-lift transonic cruise condition showed a decrease in code-to-code variation with grid refinement as expected. For the same flight condition, the wing/body/nacelle/pylon total drag and the nacelle/pylon drag increment predicted showed an increase in code-to-code variation with grid refinement. Although the range in total drag for the wingbody fine grids was only 5 counts, a code-to-code comparison of surface pressures and surface restricted streamlines indicated that the three solvers were not all converging to the same flow solutions- different shock locations and separation patterns were evident. Similarly, the wing/body/nacelle/pylon solutions did not appear to be converging to the same flow solutions. Overall, grid refinement did not consistently improve the correlation with experimental data for either the wingbody or the wing/body/nacelle pylon configuration. Although the absolute values of total drag predicted by two of the solvers for the medium and fine grids did not compare well with the experiment, the incremental drag predictions were within plus or minus 3 counts of the experimental data. The correlation with experimental incremental drag was not

  15. High Bypass Ratio Jet Noise Reduction and Installation Effects Including Shielding Effectiveness

    Science.gov (United States)

    Thomas, Russell H.; Czech, Michael J.; Doty, Michael J.

    2013-01-01

    An experimental investigation was performed to study the propulsion airframe aeroacoustic installation effects of a separate flow jet nozzle with a Hybrid Wing Body aircraft configuration where the engine is installed above the wing. Prior understanding of the jet noise shielding effectiveness was extended to a bypass ratio ten application as a function of nozzle configuration, chevron type, axial spacing, and installation effects from additional airframe components. Chevron types included fan chevrons that are uniform circumferentially around the fan nozzle and T-fan type chevrons that are asymmetrical circumferentially. In isolated testing without a pylon, uniform chevrons compared to T-fan chevrons showed slightly more low frequency reduction offset by more high frequency increase. Phased array localization shows that at this bypass ratio chevrons still move peak jet noise source locations upstream but not to nearly the extent, as a function of frequency, as for lower bypass ratio jets. For baseline nozzles without chevrons, the basic pylon effect has been greatly reduced compared to that seen for lower bypass ratio jets. Compared to Tfan chevrons without a pylon, the combination with a standard pylon results in more high frequency noise increase and an overall higher noise level. Shielded by an airframe surface 2.17 fan diameters from nozzle to airframe trailing edge, the T-fan chevron nozzle can produce reductions in jet noise of as much as 8 dB at high frequencies and upstream angles. Noise reduction from shielding decreases with decreasing frequency and with increasing angle from the jet inlet. Beyond an angle of 130 degrees there is almost no noise reduction from shielding. Increasing chevron immersion more than what is already an aggressive design is not advantageous for noise reduction. The addition of airframe control surfaces, including vertical stabilizers and elevon deflection, showed only a small overall impact. Based on the test results, the best

  16. 乌苏大桥主桥上部结构设计与计算%Design and Calculation of Superstructure of Main Bridge of Wusu Bridge

    Institute of Scientific and Technical Information of China (English)

    康晋; 肖海珠; 徐伟

    2011-01-01

    The main bridge of the Wusu Bridge is a single pylon and single cable plane cablestayed bridge with span arrangement (140+140) m and with a structural system of rigid fixity of the pylon, pier and girder. A summarized account of the design and calculation of the superstructure of the bridge is presented herewith. The main girder of the bridge is a composite girder with long cantilevers, the central part of the girder is designed as a two-cell and single-box steel girder and the steel cantilever at each side of the girder is the variable depth I-beam and is provided wiht a trough stringer at the far side, which are all topped with 25 cm thick concrete deck slabs connected with the girder via shearing studs. The part of the main girder close to the pylon is designed as a prestressed concrete box girder to facilitate the fixity of the girder with the pylon. The pylon is the single column pylon, 117 m in height. The stay cables, made up of low relaxation galvanized high strength parallel steel wire strands, are of the harp pattern cable plane arranged in the central alignment of the bridge deck. The finite element software MIDAS Civil 2006 and the SCDS programme are employed to calculate and analyze structure of the bridge. The results of the calculation and analysis indicate that the static, stability and dynamic characteristics of the bridge can meet the requirements in the relevant codes.%乌苏大桥主桥为独塔单索面斜拉桥,跨径布置为(140+140) m,采用塔、墩、梁固结体系,综述该桥上部结构设计与计算.主梁为带大挑臂的钢箱结合梁,中间钢箱梁采用单箱双室截面,两侧钢挑臂为变高度工字形梁,挑臂端部设槽形小纵梁;混凝土桥面板厚25 cm,与钢梁通过剪力钉连接;塔根部主梁采用预应力混凝土箱梁,以方便与桥塔固结;桥塔采用独柱式塔,高117 m;斜拉索为竖琴形中央平行索面布置,采用低松弛镀锌高强度平行钢丝束.采用有限元软件MIDAS Civil

  17. 大涵道比翼吊发动机喷流气动干扰研究%Interference effects of wing-mounted high bypass ratio nacelle with engine power

    Institute of Scientific and Technical Information of China (English)

    乔磊; 白俊强; 华俊; 陈迎春; 张淼; 张美红

    2014-01-01

    研究了涡扇动力翼吊布局飞机考虑动力效应时的流场数值模拟和气动干扰的若干问题。在数值模拟方法方面,介绍了便于实际工程应用的发动机进排气边界状态参数设定算法;通过设定无总温总压增量的喷口边界模拟发动机的无动力状态,避免了研究喷流效应时由通气短舱和喷气构型之间的几何外形差异带来的网格差异对计算结果的影响,提高了复杂构型流场数值模拟结果的可信度。通过数值模拟发现,发动机喷流的引射虽然可使气流加速从而降低翼面压力,但发动机做功导致的翼面压力抬升亦不可忽视。发动机喷流可能引发强烈的挂架气动干扰,其原因是由机身、发动机、机翼和挂架构成的收缩-扩张流道引起的气流加速。通过适当延长和增厚挂架可以削弱这种干扰。%Numerical simulation method and aerodynamic interference effects of wing-mounted nacelle aircraft were studied.In aspect of numerical simulation,a practical engineering compatible algorithm for the determination of engine intake and exhaust boundary parameters directly from free stream and engine work-ing conditions was developed.Mesh difference arises from geometry inconsistency between powered and un-powered nacelle,which is a confounding factor when estimating power effect,is eliminated via set up a zero-energy-increase exhaust boundary condition.Then,the credibility of numerical simulation result of complex configuration in aircraft design was improved.The numerical simulation results shown that the engine power has two opposite aspects of effects on wing surface pressure,one is that engine ejection speed the flow up and bring the pressure down,the other is that the engine increasesd the pressure near the nuzzle.The numerical simulation result also revealed that engine jet stream can induce severe flow interferences on surface of pylon, duel to the flow acceleration through the

  18. Saker Falcon on the Crimean Peninsula

    Directory of Open Access Journals (Sweden)

    Igor V. Karyakin

    2016-02-01

    Full Text Available In this article we made a revaluation of a number of the Saker (Falco cherrug on the Crimean Peninsula based on data obtained in an expedition conducted in May 9–26 of 2015. During this expedition Sakers were observed on 58 sites (31 times they were seen on pylons of power lines, 14 – on cliffs in the foothills of Crimean Mountains, 8 – on the coastal cliffs and 4 on the coastal precipices, and one adult male was seen in the forest shelter belt near Syvash lagoon. We revealed 49 breeding territories of Saker including 42 occupied nests with successful breeding. The estimation of the total number of breeding population on peninsula is 145–184 (mean 165 breeding pairs, including 125–159 (mean 142 pairs which breeding attempts were successful in 2015. The distance between the neighboring pairs is 1.95–15.21 km (mean 6.56±3.37 km, n=43. Pylons of power lines were used by 30 breeding pairs (61.22% out of 49, and 29 successful nests (69.05% out of 42 were built on pylons. Supposedly, 63.83% of all breeding pairs in Crimea are bred on pylons, and the percentage of successful nests out of the total number of nests in population is 71.89%. From the 34 nests that were built on pylons, 24 (70.59% were located on the concrete pylons and 10 (29.41% on the metal ones. On cliffs and precipices we found 24 nests in total. Eighteen (75% of them were built on a bare ground, while the others were found in the nests built by other bird species (most of them were made in the former nests of the Raven (Corvus corax, and one pair occupies a nest of the Long-legged Buzzard (Buteo rufinus located on cliff. The percentage of successful nests out of occupied ones was 85.71%. We found broods of 1–4 nestlings, which in average (n=23 makes 2.83±0.78 nestling per successful nest. The majority of broods (65.22% consisted of 3 nestlings. On 20 breeding territories (90.91% male birds were older then 2 years old, and two breeding territories (9.09% were occupied

  19. Key Techniques for Design of Edong Changjiang River Highway Bridge%鄂东长江公路大桥设计关键技术

    Institute of Scientific and Technical Information of China (English)

    胡明义; 黄冰释; 余俊林; 唐守峰

    2011-01-01

    The main bridge of Edong Changjiang River Highway Bridge is a semi-floating system hybrid girder cable-stayed bridge with double pylons, double cable planes and with a main span 926 m. The main girder of the bridge was designed as the PK (Pasco-Kennewick Bridge) cross section of separated twin boxes, of which the part of the girder for the central span is of the steel box girder, the parts of the girder for the side spans are of the prestressed concrete (PC) box girders and a steel and concrete joint section was set on each side of the central span at a distance of 12. 5 m to the center of a pylon. To ensure a smooth transition between the steel and concrete structure, the multi-cell force transmission structure with PBL shear connectors was used for the joint section. The cable-to-pylon anchorage is the steel anchor box structure built in the column of a pylon. To control the development of concrete cracks in the anchorage zone in the pylon, the prestressing strands of 12φs 15. 24 were set in the concrete pylon wall on the side of the anchorage. To enhance the structural durability and service life, the durability of reinforced concrete and corrosion protection of steel structure were designed and the life cycle cost concept was applide to the design. The inspection and maintenance accesses for all principal components of the bridge were provided and the inspection and maintenance cycles, replacement criteria, workmanship and technical requirements were formulated as well.%鄂东长江公路大桥主桥为主跨926 m的双塔双索面半飘浮体系混合梁斜拉桥,主梁采用分离式双箱PK断面形式,中跨为钢箱梁,边跨为PC箱梁,钢-混凝土结合段设于中跨距桥塔中心12.5m处.为使钢结构与混凝土结构平稳过渡,钢-混凝土结合段采用PBL剪力连接器的多格室传力构造.索塔锚固采用在塔柱内置钢锚箱的构造,为控制锚固区混凝土裂缝开展,在锚固侧混凝土塔壁内设置12(o)s15.24预应力

  20. Design of Main Bridge of Xi′nan Bridge in Guigang City,Guangxi%广西贵港西南大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    李翠霞; 张巨生

    2015-01-01

    广西贵港市西南大桥主桥为(46+88+280+88+46) m双塔双索面预应力混凝土边主梁斜拉桥。主梁采用等高度带悬臂的矩形混凝土边主梁与“工”字形钢横梁相结合的形式,整幅桥面宽36.5m,设双向2.0%横坡。桥塔采用“鱼”状流线弧形框架钢筋混凝土结构,塔柱高102.5 m,采用外侧为“D”形圆弧段的箱形截面。桥塔设上、下横梁,均采用预应力混凝土单箱单室结构。全桥共设136根斜拉索,斜拉索采用φs 15.2 m m镀锌钢绞线索,空间双索面扇形布置。桥塔墩采用分离式基础,上、下游分离式基础中心距34.7 m ,其下各设9根φ2.5 m钻孔桩。承台为正方形钢筋混凝土结构。4号墩顶面设一圆端形塔座。%The main bridge of the Xi′nan Bridge in Guigang City ,Guangxi is a prestressed concrete edge main girders cable‐stayed bridge with double pylons ,double cable planes and with span arrangement (46+88+280+88+46) m .T he main girders of the bridge are of the structural type combining the rectangular concrete edge main girders having constant depth and cantilevers with the I‐shape steel cross beams .The width of the whole bridge deck is 36 .5 m and the deck is provided with dual 2 .0% transverse slopes .A pylon of the bridge is the“fish”‐shape streamlined arc frame reinforced concrete structure that is 102 .5 m in height and the outer side of the pylon is of the“D”‐shape round arc box section .The upper and lower cross beams of the pylon are all the prestressed concrete single‐cell single‐box structures .There are totally 136 stay cables arranged for the whole bridge .The stay cables are the φs 15 .2 mm galvanized steel wire strand cables and are arranged in fan shape and spatial double cable planes .The pylon pier is supported on the sep‐arated foundations .T he center‐to‐center distance of the foundations on the upstream and dow n‐stream sides is 34 .7

  1. Research on the Different Surfaces of Aircraft Space Truss Type Weldment Manufacturing Technology%关于飞机空间异面桁架类焊接件制造技术的研究

    Institute of Scientific and Technical Information of China (English)

    李晓宁; 肖望东; 王声; 黄蓉; 张大均

    2016-01-01

    The winglet rack of a certain type of aircraft is as an example to present a typical spatial plane truss welding manufacturing method and way .Through the description of a certain type of aircraft wing pylon structure characteristic ,in-troduce the process of a certain type of aircraft wing pylons ,industry and trade dress design idea ,and how to use reverse measurement technology to resolve the difficulties in the process of development ,and finally achieve a certain type of aircraft wing pylons delivery and assembly .Its successful development provides the valuable experience for the manufacture of wel-ded assemblies of space plane truss structures ,which is of great reference value for the development of space plane truss type welding parts .%以某型机小翼挂架为例,研究了一种典型的空间异面桁架类焊接件制造方法与途径.通过对某型机小翼挂架结构特点的描述,详细介绍了某型机小翼挂架的工艺方法、工装设计思路,以及如何利用逆向测量技术解决研制过程中的难点,最终实现某型机小翼挂架的交付与装配.它的成功研制为空间异面类桁架结构焊组件的制造提供了宝贵的经验,对空间异面桁架类焊接件的研制具有借鉴与指导意义.

  2. Effects of fuel injection on mixing and upstream interactions in supersonic flow

    Science.gov (United States)

    Tu, Qiuya

    Scramjet engine performance has been studied experimentally and computationally almost under steady-state conditions. Transients of the airflow and fueling in the scramjet's isolator or combustor create important fluid-dynamic/ combustion interactions. Spark schlieren photography was employed to study the effects of pressure rise in the combustion chamber on the isolator flow at three conditions with isolator entrance Mach number of 1.6, 1.9 and 2.5, covering the range of dual-mode combustion and transition to full scramjet operation. Heat release through combustion in the model scramjet was simulated by incrementally blocking the flow exit until upstream-interaction was induced and a shock train formed in the isolator. Theoretical predictions of the pressure rise in the isolator under separated flow conditions were calculated, which agreed well with the experimental data. The prediction is sensitive to the accurate modeling of the isolator inlet conditions and the correct selection of wall friction coefficient. Gaseous helium and argon have been transversely injected into a Mach 1.6 airflow simulating a light and a heavy fuel injection behind a thin triangular pylon placed upstream, in the isolator, which has a negligible impact on pressure losses. Planar laser-induced fluorescence (PLIF) was used to observe the penetration and mixing in the test section at three cross-sections including the recirculation region and beyond. Results were compared to the no-pylon cases, which showed the presence of the pylon resulted in improving both penetration and spreading of the jet. Simulation for shock wave/ boundary-layer interaction was conducted in Fluent for case of M=1.9 at 60% blockage by using k-ε RNG model with two different near wall treatments. In both cases, the shock ran out of isolator before the computation converged, this is different from experimental results. Proper actual wall friction force may have a very important effect on the computation, which needs

  3. Measurement of waterborne radon in the drinking water of the Dera Ismail Khan city using active and passive techniques

    Directory of Open Access Journals (Sweden)

    Nasir Tabassum

    2015-01-01

    Full Text Available Groundwater is considered to be the second largest contributor to the indoor radon concentration after soil. Therefore, measurement of waterborne radon has remained a point of interest for many researchers. The main objective of this study is to study waterborne radon activity in the city of Dera Ismail Khan. In this context, water samples were collected from different locations of the city and waterborne radon was measured using a pylon vacuum water degassing system and CR-39 based radon detectors. The pylon system measured waterborne radon activities in samples of hand pumps and motor driven pumps varying from 0.015 to 0.066 Bq/L and 0.021 to 0.145 Bq/L with average values of 0.041 ± 0.015 Bq/L and 0.076 ± 0.024 Bq/L, respectively. Whereas CR-39 based measured values ranged from 0.042 to 0.125 Bq/L and 0.075 to 0.158 Bq/L with average values of 0.081 ± 0.021 Bq/L and 0.120 ± 0.020 Bq/L, respectively. The estimated average annual effective dose due to ingestion of radon from drinking water using pylon and CR-39 based radon detectors for hand and motor pump samples was found to be 1.055×10-4 mSv and 1.947×10-4 mSv, and 2.067×10-4 mSv and 3.058×10-4 mSv, respectively. The waterborne radon concentrations and as a result the annual effective dose expected to be received from it are within the recommended safe limits.

  4. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  5. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Yuan Hong; Pei Minshan; Dai Jie; Xu Lin

    2009-01-01

    The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1 088 m within cable-stayed bridges. To overcome problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper.

  6. Next-Generation Web Frameworks in Python

    CERN Document Server

    Daly, Liza

    2007-01-01

    With its flexibility, readability, and maturecode libraries, Python is a naturalchoice for developing agile and maintainableweb applications. Severalframeworks have emerged in the last fewyears that share ideas with Ruby on Railsand leverage the expressive nature of Python.This Short Cut will tell you whatyou need to know about the hottest fullstackframeworks: Django, Pylons, andTurboGears. Their philosophies, relativestrengths, and development status aredescribed in detail. What you won't find out is, "Which oneshould I use?" The short answer is thatall of them can be used to build web appl

  7. High-fidelity Simulation of Jet Noise from Rectangular Nozzles . [Large Eddy Simulation (LES) Model for Noise Reduction in Advanced Jet Engines and Automobiles

    Science.gov (United States)

    Sinha, Neeraj

    2014-01-01

    This Phase II project validated a state-of-the-art LES model, coupled with a Ffowcs Williams-Hawkings (FW-H) far-field acoustic solver, to support the development of advanced engine concepts. These concepts include innovative flow control strategies to attenuate jet noise emissions. The end-to-end LES/ FW-H noise prediction model was demonstrated and validated by applying it to rectangular nozzle designs with a high aspect ratio. The model also was validated against acoustic and flow-field data from a realistic jet-pylon experiment, thereby significantly advancing the state of the art for LES.

  8. Data Summary Report for the Open Rotor Propulsion Rig Equipped With F31/A31 Rotor Blades

    Science.gov (United States)

    Stephens, David

    2014-01-01

    An extensive wind tunnel test campaign was undertaken to quantify the performance and acoustics of a counter-rotating open rotor system. The present document summarizes the portion of this test performed with the so-called Historical Baseline rotor blades, designated F31A31. It includes performance and acoustic data acquired at Mach numbers from take-off to cruise. It also includes the effect of propulsor angle of attack as well as an upstream pylon. This report is accompanied by an electronic data set including relevant acoustic and performance measurements for all of the F31A31 data.

  9. Investigation of difficult component effects on FEM vibration prediction for the AH-1G helicopter

    Science.gov (United States)

    Dompka, Robert V.

    1988-01-01

    Under the NASA-sponsored Design Analysis Methods for Vibrations program, a series of ground vibration tests and NASTRAN finite element model correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Secondary structure and damping were found to have significant effects on the frequency response of the airframe above 15 Hz. The nonlinear effects of thrust stiffening and elastomeric mounts on the low-frequency pylon modes below the main rotor were also significant.

  10. Reduction of vertical-gust induced loads on elastic airplane model with slotted-interceptor-type surfaces

    Science.gov (United States)

    Mazutsky, A. Yu.

    2007-06-01

    Results of T-203 wind-tunnel tests of an elastic airplane model dynamically similar to Tu-204 aircraft equipped with a passive wing load reduction system are reported. The wing load reduction system comprised two auxiliary aerodynamic surfaces of the slotted-interceptor type installed symmetrically on the upper surface of the lifting wing at the boundary-layer height. It was found that, with the operating system, the additional bending moments induced by symmetric vertical discrete gusts in the wing root and at the fuselage mid-body decreased by 20%, with simultaneous increase observed in the flexure-pylon flutter speed.

  11. Navigation, Guidance and Control For the CICADA Expendable Micro Air Vehicle

    Science.gov (United States)

    2015-01-01

    mounted on wing pylon drop mechanisms located on each wing of the Tempest. The Tempest was needed to carry the CICADAs back within range of the recovery...in shown in Figure 1b. The wing of the CICADA is made from the same FR4 fiberglass sheet material which the fuselage/circuit board is made of...Lightning holes were cut into the wing , and covered with common packing tape. Pitch and roll control is provided by elevons at the trailing edge of the wing

  12. RTO Meeting Proceedings 16, Aircraft Weapon System Compatibility and Integration held in Chester, United Kingdom, 28-30 September, 1998

    Science.gov (United States)

    1999-04-01

    Instituto Superior Tecnico The BOEING Company Torre-6o Pais P.O. Box 3999 1096 Lisboa Codex Mail Stop 85-93 Portugal Seattle, WA 98124-2499 United States...all the 2-3 weightings. However for these situations criteria specified by the user. That point data manual matching can be equally problematic. is then...between the The Aircraft/Stores Interface Manual was used to exhaust nozzles was also distorted and projected to the position the pylons and the tank

  13. Prosthetic options for below knee amputations after osteomyelitis and nonunion of the tibia.

    Science.gov (United States)

    Moshirfar, A; Showers, D; Logan, P; Esterhai, J L

    1999-03-01

    Below the knee amputation after trauma is an appropriate option for many patients with recalcitrant infection and nonunion of the tibia. Patients who have had transtibial amputations have lower energy expenditure, heart rate, and oxygen cost when ambulating with their prostheses than when using a three-point gait with crutches without their artificial limb. Innovative prosthetists have improved each of the five essential components of the limb amputated below the knee: socket, insert, shaft and pylon, foot and ankle assembly, and suspension system. Prosthetists are integral members of the patient's healthcare team. Their recommendations and direct patient care are essential to optimizing the functional ability of patients who have had amputations.

  14. Aerodynamic analysis of complex configurations using unstructured grids

    Science.gov (United States)

    Frink, Neal T.; Parikh, Paresh; Pirzadeh, Shahyar

    1991-01-01

    The purpose of this paper is to assess the accuracy and utility of a new unstructured, inviscid, upwind flow solver for the aerodynamic analysis of two aircraft configurations. The two configurations consist of a low-wing transport with nacelle/pylon on and off, and a generic high-speed civil transport. Computations are made at subsonic and transonic Mach numbers for the low-wing transport and at transonic and low-supersonic speeds for the high-speed civil transport. The results include an assessment of grid sensitivity and provide comparisons with experimental data.

  15. Defense AT&L (Volume 36, Number 2, March-April 2007)

    Science.gov (United States)

    2007-04-01

    13 Defense AT&L: March-April 2007 MAI Technologies and the DoD and NASA Systems Impacted • High-Yield Investment Cast Superalloy Airfoils –F135, F136...E/F Drag Beam –F-22 Keelson and F-35 Weapons Bay Door Hinge –C-17 Pylon Panel and Structural Support –AE1107, AE2100 and AE3007H Compressor Discs ...Forged Titanium Alloy Modeling –F119 Fan Blades and Discs –F135, F136 Fan Discs and F-22 Plate Airframe Structure • Direct Electron-Beam-Melted

  16. Blade loss transient dynamics analysis, volume 1. Task 1: Survey and perspective. [aircraft gas turbine engines

    Science.gov (United States)

    Gallardo, V. C.; Gaffney, E. F.; Bach, L. J.; Stallone, M. J.

    1981-01-01

    An analytical technique was developed to predict the behavior of a rotor system subjected to sudden unbalance. The technique is implemented in the Turbine Engine Transient Rotor Analysis (TETRA) computer program using the component element method. The analysis was particularly aimed toward blade-loss phenomena in gas turbine engines. A dual-rotor, casing, and pylon structure can be modeled by the computer program. Blade tip rubs, Coriolis forces, and mechanical clearances are included. The analytical system was verified by modeling and simulating actual test conditions for a rig test as well as a full-engine, blade-release demonstration.

  17. Development of a mirror pointing mechanism for an atmospheric gas measurement instrument

    Science.gov (United States)

    Graham, Michael; Belous, Adel; Brown, Jeff; Podolske, James

    1998-01-01

    Development of the Open Path Tunable Infrared Monitor of the Atmosphere (OPTIMA) instrument involved designing a pair of motion systems that could maintain a precise alignment and spatial distance between two mirrors installed on the NASA DC-8 research laboratory aircraft. This is the first airborne optical instrument that allows direct measurement of the gases in the freestream airflow on the exterior of the aircraft. One mirror is mounted within a specially constructed open port cavity in the cabin of the aircraft and the second is mounted 6 meters away on top of the inboard port side (number 2) engine pylon. Three co-aligned laser beams are reflected between the two mirrors 64 times in a Herriott pattern. The resulting sample path length of 384 meters is used to perform a spectral absorption analysis of the airflow between the mirrors. To compensate for normal wing movement and engine oscillations both mirrors were designed as continuously driven mechanisms to maintain alignment within allowable limits. The motion systems of the two mirror assemblies provide five degrees of freedom and are designed to maintain a pointing accuracy within seven arc-sec with a response frequency in excess of 10 Hz. The pylon motion system incorporates controlled pitch and yaw movement. The fuselage motion system compensates for pitch variation as well as linear translation for focal length and vertical aiming of the laser beam via a controlled beam guidance mechanism.

  18. I-5/Gilman advanced technology bridge project

    Science.gov (United States)

    Lanza di Scalea, Francesco; Karbhari, Vistasp M.; Seible, Frieder

    2000-04-01

    The UCSD led I-5/Gilman Advanced Technology Bridge Project will design and construct a fully functional traffic bridge of advanced composite materials across Interstate 5 in La Jolla, California. Its objective is to demonstrate the use of advanced composite technologies developed by the aerospace industry in commercial applications to increase the life expectancy of new structures and for the rehabilitation of aging infrastructure components. The structure will be a 450 ft long, 60 ft wide cable-stayed bridge supported by a 150 ft A-frame pylon with two vehicular lanes, two bicycle lanes, pedestrian walkways and utility tunnels. The longitudinal girders and pylon will be carbon fiber shells filled with concrete. The transverse deck system will consist of hollow glass/carbon hybrid tubes and a polypropylene fiber reinforced concrete deck with an arch action. Selected cables will be composite. The bridge's structural behavior will be monitored to determine how advanced composite materials perform in civil infrastructure applications. The bridge will be instrumented to obtain performance and structural health data in real time and, where possible, in a remote fashion. The sensors applied to the bridge will include electrical resistance strain gages, fiberoptic Bragg gratings and accelerometers.

  19. Research on Collapse Process of Cable-Stayed Bridges under Strong Seismic Excitations

    Directory of Open Access Journals (Sweden)

    Xuewei Wang

    2017-01-01

    Full Text Available In order to present the collapse process and failure mechanism of long-span cable-stayed bridges under strong seismic excitations, a rail-cum-road steel truss cable-stayed bridge was selected as engineering background, the collapse failure numerical model of the cable-stayed bridge was established based on the explicit dynamic finite element method (FEM, and the whole collapse process of the cable-stayed bridge was analyzed and studied with three different seismic waves acted in the horizontal longitudinal direction, respectively. It can be found from the numerical simulation analysis that the whole collapse failure process and failure modes of the cable-stayed bridge under three different seismic waves are similar. Furthermore, the piers and the main pylons are critical components contributing to the collapse of the cable-stayed bridge structure. However, the cables and the main girder are damaged owing to the failure of piers and main pylons during the whole structure collapse process, so the failure of cable and main girder components is not the main reason for the collapse of cable-stayed bridge. The analysis results can provide theoretical basis for collapse resistance design and the determination of critical damage components of long-span highway and railway cable-stayed bridges in the research of seismic vulnerability analysis.

  20. Investigation of difficult component effects on finite element model vibration prediction for the Bell AH-1G helicopter. Volume 1: Ground vibration test results

    Science.gov (United States)

    Dompka, R. V.

    1989-01-01

    Under the NASA-sponsored Design Analysis Methods for VIBrationS (DAMVIBS) program, a series of ground vibration tests and NASTRAN finite element model (FEM) correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Previous correlations of the AH-1G showed good agreement between NASTRAN and tests through 15 to 20 Hz, but poor agreement in the higher frequency range of 20 to 30 Hz. Thus, this effort emphasized the higher frequency airframe vibration response correlations and identified areas that need further R and T work. To conduct the investigations, selected difficult components (main rotor pylon, secondary structure, nonstructural doors/panels, landing gear, engine, fuel, etc.) were systematically removed to quantify their effects on overall vibratory response of the airframe. The entire effort was planned and documented, and the results reviewed by NASA and industry experts in order to ensure scientific control of the testing, analysis, and correlation exercise. In particular, secondary structure and damping had significant effects on the frequency response of the airframe above 15 Hz. Also, the nonlinear effects of thrust stiffening and elastomer mounts were significant on the low frequency pylon modes below main rotor 1p (5.4 Hz). The results of the ground vibration testing are presented.

  1. Investigation of difficult component effects on finite element model vibration prediction for the Bell AG-1G helicopter. Volume 2: Correlation results

    Science.gov (United States)

    Dompka, R. V.

    1989-01-01

    Under the NASA-sponsored DAMVIBS (Design Analysis Methods for VIBrationS) program, a series of ground vibration tests and NASTRAN finite element model (FEM) correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Previous correlations of the AG-1G showed good agreement between NASTRAN and tests through 15 to 20 Hz, but poor agreement in the higher frequency range of 20 to 30 Hz. Thus, this effort emphasized the higher frequency airframe vibration response correlations and identified areas that need further R and T work. To conduct the investigations, selected difficult components (main rotor pylon, secondary structure, nonstructural doors/panels, landing gear, engine, furl, etc.) were systematically removed to quantify their effects on overall vibratory response of the airframe. The entire effort was planned and documented, and the results reviewed by NASA and industry experts in order to ensure scientific control of the testing, analysis, and correlation exercise. In particular, secondary structure and damping had significant effects on the frequency response of the airframe above 15 Hz. Also, the nonlinear effects of thrust stiffening and elastomer mounts were significant on the low frequency pylon modes below main rotor 1p (5.4 Hz). The results of the NASTRAN FEM correlations are given.

  2. Impact testing of the residual limb: System response to changes in prosthetic stiffness

    Directory of Open Access Journals (Sweden)

    Erin Boutwell, PhD

    2016-04-01

    Full Text Available Currently, it is unknown whether changing prosthetic limb stiffness affects total limb stiffness and/or influences the shock absorption of an individual with transtibial amputation. The hypotheses tested within this study are that a decrease in longitudinal prosthetic stiffness will produce (1 reduced total limb stiffness and (2 reduced magnitude of peak impact forces and increased time delay to peak force. Fourteen subjects with a transtibial amputation participated in this study. Prosthetic stiffness was modified by means of a shock-absorbing pylon that provides reduced longitudinal stiffness through compression of a helical spring within the pylon. A sudden loading evaluation device was built to examine changes in limb loading mechanics during a sudden impact event. No significant change was found in the peak force magnitude or timing of the peak force between prosthetic limb stiffness conditions. Total limb stiffness estimates ranged from 14.9 to 17.9 kN/m but were not significantly different between conditions. Thus, the prosthetic-side total limb stiffness was unaffected by changes in prosthetic limb stiffness. The insensitivity of the total limb stiffness to prosthetic stiffness may be explained by the mechanical characteristics (i.e., stiffness and damping of the anatomical tissue within the residual limb.

  3. 襟缝翼对民用飞机失速特性的影响%Effect of Slat and Flap on Stall Characteristic of Civil Aircraft

    Institute of Scientific and Technical Information of China (English)

    周涛; 李亚林; 梁益华; 陈迎春

    2012-01-01

    To detect factors of affecting stall characteristic and stability of aircraft, slot parameter of out board slat, separation face of inboard slat and fuselage, slot between slat and pylon, and slot parameter of flap were investigated. The results indicate that, root and tip of slat may affect pitching moment character- istic, slot between slat and pylon may improve lift coefficient, but no contribution for pitching moment characteristic, and, adjusting deploy angle of flap may not improve separation characteristic on main wing, because effective camber of wing is not changed.%从外侧缝翼缝道参数、内侧缝翼分离面、缝翼与挂架间隙以及后缘襟翼缝道参数等方面考虑,分析了民用飞机失速特性和失稳特性的影响因素.结果表明,前缘缝翼根部和梢部细节对力矩特性有较大影响,缝翼挂架堵缝可提高升力,不影响力矩特性,调整襟翼偏角,可改变机翼有效弯度,不改变主翼分离特性.

  4. Identification of Nonlinearities in Joints of a Wing Structure

    Directory of Open Access Journals (Sweden)

    Sani M.S.M.

    2016-01-01

    Full Text Available Nonlinear structural identification is essential in engineering. As new materials are being used andstructures become slender and lighter, nonlinear behaviour of structures becomes more important. There have been many studies into the development and application of system identification methods for structural nonlinearity based on changes in natural frequencies, mode shapes and damping ratios. A great challenge is to identify nonlinearity in large structural systems. Much work has been undertaken in the development of nonlinear system identification methods (e.g. Hilbert Transform, NARMAX, and Proper Orthogonal Decomposition, however, it is arguable that most of these methods are cumbersome when applied to realistic large structures that contain mostly linear modes with some local nonlinearity (e.g. aircraft engine pylon attachment to a wing. In this paper, a multi-shaker force appropriation method is developed to determine the underlying linear and nonlinear structural properties through the use of the measurement and generation of restoring force surfaces. One undamped mode is excited in each multi-shaker test. Essentially, this technique is a derivative of the restoring surface method and involves a non-linear curve fitting performed in modal space. A reduced finite element model is established and its effectiveness in revealing the nonlinear characteristics of the system is discussed. The method is demonstrated through both numerical simulations and experiments on a simple jointed laboratory structure with seeded faults, which represents an engine pylon structure that consists of a rectangular wing with two stores suspended underneath.

  5. The influence of geometry on jet plume development

    Science.gov (United States)

    Xia, H.; Tucker, P. G.; Eastwood, S.; Mahak, M.

    2012-07-01

    Our recent efforts of using large-eddy simulation (LES) type methods to study complex and realistic geometry single stream and co-flow nozzle jets and acoustics are summarized in this paper. For the LES, since the solver being used tends towards having dissipative qualities, the subgrid scale (SGS) model is omitted, giving a numerical type LES (NLES). To overcome near wall streak resolution problems a near wall RANS (Reynolds averaged Navier-Stokes) model is smoothly blended in the LES making a hybrid RANS-NLES approach. Several complex nozzle geometries including the serrated (chevron) nozzle, realistic co-axial nozzles with eccentricity, pylon and wing-flap are discussed. The hybrid RANS-NLES simulations show encouraging predictions for the chevron jets. The chevrons are known to increase the high frequency noise at high polar angles, but decrease the low frequency noise at lower angles. The deflection effect of the potential core has an important mechanism of noise reduction. As for co-axial nozzles, the eccentricity, the pylon and the deployed wing-flap are shown to influence the flow development, especially the former to the length of potential core and the latter two having a significant impact on peak turbulence levels and spreading rates. The studies suggest that complex and real geometry effects are influential and should be taken into count when moving towards real engine simulations.

  6. 3D mechanical analysis of aeronautical plain bearings: Validation of a finite element model from measurement of displacement fields by digital volume correlation and optical scanning tomography

    Science.gov (United States)

    Germaneau, A.; Peyruseigt, F.; Mistou, S.; Doumalin, P.; Dupré, J.-C.

    2010-06-01

    On Airbus aircraft, spherical plain bearings are used on many components; in particular to link engine to pylon or pylon to wing. Design of bearings is based on contact pressure distribution on spherical surfaces. To determine this distribution, a 3D analysis of the mechanical behaviour of aeronautical plain bearing is presented in this paper. A numerical model has been built and validated from a comparison with 3D experimental measurements of kinematic components. For that, digital volume correlation (DVC) coupled with optical scanning tomography (OST) is employed to study the mechanical response of a plain bearing model made in epoxy resin. Experimental results have been compared with the ones obtained from the simulated model. This comparison enables us to study the influence of various boundary conditions to build the FE model. Some factors have been highlighted like the fitting behaviour which can radically change contact pressure distribution. This work shows the contribution of a representative mechanical environment to study precisely mechanical response of aeronautical plain bearings.

  7. Incorporation of Half-Cycle Theory Into Ko Aging Theory for Aerostructural Flight-Life Predictions

    Science.gov (United States)

    Ko, William L.; Tran, Van T.; Chen, Tony

    2007-01-01

    The half-cycle crack growth theory was incorporated into the Ko closed-form aging theory to improve accuracy in the predictions of operational flight life of failure-critical aerostructural components. A new crack growth computer program was written for reading the maximum and minimum loads of each half-cycle from the random loading spectra for crack growth calculations and generation of in-flight crack growth curves. The unified theories were then applied to calculate the number of flights (operational life) permitted for B-52B pylon hooks and Pegasus adapter pylon hooks to carry the Hyper-X launching vehicle that air launches the X-43 Hyper-X research vehicle. A crack growth curve for each hook was generated for visual observation of the crack growth behavior during the entire air-launching or captive flight. It was found that taxiing and the takeoff run induced a major portion of the total crack growth per flight. The operational life theory presented can be applied to estimate the service life of any failure-critical structural components.

  8. Design and cost of the first commercial stretched-membrane heliostat

    Science.gov (United States)

    Brown, D.; Konnerth, A., III; Schertz, P. T.; White, D.

    1991-07-01

    A complete design of an 50 sq m stretched-membrane heliostat was developed specifically for the early stages of manufacturing. The design included mirror-module refinements, drive selection, pylon and foundation design, and detailing and tracking control design. The mirror module and rear structure are highly similar to the Mark II prototype erected at Sandia National Laboratories, Albuquerque, 1989. The pylon and foundation consist of a single pipe set in a cast-in-place pier as successfully developed at Sandia. The unique tracking control uses only commercially available industrial control components. Also, all real-time communication requirements have been eliminated to assure against the most common source of malfunctions in previous central receiver fields. Control commands are calculated internally to the local controller using a polynomial approximation curve fitted to actual sun position and adjusted for individual heliostat requirements. Direct material costs, in 1990 dollars were obtained for several different production volumes from material and component manufacturers and subassembly subcontractors. Manufacturing costs for a low-volume production company are projected to be competitive with glass/metal heliostats.

  9. A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    B. Asgari

    2014-01-01

    Full Text Available Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM. The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  10. A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

    Science.gov (United States)

    Asgari, B; Osman, S A; Adnan, A

    2014-01-01

    Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  11. Design of Experimental Suspended Footbridge with Deck Made of UHPC

    Directory of Open Access Journals (Sweden)

    Blank Marek

    2016-01-01

    Full Text Available This paper deals with the static and dynamic design of experimental footbridge for pedestrians and cyclists in the municipality Lužec nad Vltavou in Czech Republic, Europe. This work aims to familiarize the reader with calculations carried out and the results obtained, describing the static and dynamic properties of proposed footbridge. The construction of footbridge is designed as a suspended structure with prestressed bridge deck consisting of prefabricated UHPC panels and reversed “V” shaped steel pylon with height of approximately 40 meters. The deck is anchored using 24 steel hangers in one row in a steel pylon - 17 ropes in the main span and 7 cables on the other side. Range of the main span is 99.18 meters and the secondary span is 31.9 m. Deck width is 4.5 meters with 3.0 meters passing space. The bridge is designed for the possibility of passage of vehicles weighting up to 3.5 tons. Deck panels are made of UHPC with reinforcement. At the edge of the bridge on the side of the shorter span the bridge deck is firmly connected with abutment and on the other deck it is stored using a pair of sliding bearings. The utilization of the excellent properties of UHPC allows to design a very thin and lightweight construction of the deck, which could not be achieved with the use of normal concrete.

  12. Modal analysis of cable-stayed UHPC bridge

    Directory of Open Access Journals (Sweden)

    Tej Petr

    2017-01-01

    Full Text Available This paper deals with the dynamic analysis of cable-stayed UHPC bridge over the Vltava river near town Melnik in Czech Republic, Europe. Bridge serves for pedestrians and cyclists. This work aims to familiarize the reader with dynamic calculations carried out and the results obtained, describing the dynamic properties of proposed bridge. The construction of bridge is designed as a cable-stayed structure with prestressed bridge deck consisting of prefabricated UHPC panels and reversed “V” shaped steel pylon with height of approximately 40 meters. The deck is anchored using 24 steel hangers in one row in a steel pylon - 17 ropes in the main span and 7 cables on the other side. Range of the main span is 99.18 meters and the secondary span is 31.9 m. Deck width is 4.5 meters with 3.0 meters passing space. The bridge is designed for the possibility of passage of vehicles weighting up to 3.5 tonnes. Deck panels are made of UHPC with reinforcement. At the edge of the bridge on the side of the shorter span the bridge deck is firmly connected with abutment and on the other deck it is stored using a pair of sliding bearings.

  13. 3D Power Line Reconstruction from Airborne LiDAR Point Cloud of Overhead Electric Power Transmission Corridors

    Directory of Open Access Journals (Sweden)

    LIN Xiangguo

    2016-03-01

    Full Text Available 3D power line reconstruction is one of the main tasks in power line patrols using LiDAR systems mounted on helicopters. A 3D reconstruction method is proposed to reconstruct the power lines from the airborne LiDAR point clouds of the overhead electric power transmission corridors. Firstly, the pylons' LiDAR points and the initial routine trajectory of the transmission lines are employed to derive the precise information such as the locations and number of the pylons, the real routine trajectory, and the total number of spans. Secondly, the power line corridor is divided into a number of spans, the scope of each span in the XOY plane is determined, and the powerline LiDAR points are allocated into the corresponding spans where they are located. Thirdly, the powerline points of each span are clustered by the k-means algorithm in a normalized projection space, and each cluster corresponds to one power line. Finally, each power line is reconstructed based on a combination of a line model and a parabola model. Two experiments suggest that the proposed method is capable of automatically and correctly reconstructing 3D models of the long power lines with high accuracy. Moreover, it is robust to many factors such as the changing number, types, arrangements, blunders of the power lines, the changing length of the spans, and the irregular breakage of the LiDAR point clouds.

  14. Finite element analysis for the evaluation of the structural behaviour, of a prosthesis for trans-tibial amputees.

    Science.gov (United States)

    Omasta, Milan; Paloušek, David; Návrat, Tomáš; Rosický, Jiří

    2012-01-01

    The finite element analysis (FEA) has been identified as a useful tool for the stress and strain behaviour determination in lower limb prosthetics. The residual limb and prosthetic socket interface was the main subject of interest in previous studies. This paper focuses on the finite element analysis for the evaluation of structural behaviour of the Sure-flex™ prosthetic foot and other load-bearing components. A prosthetic socket was not included in the FEA. An approach for the finite element modelling including foot analysis, reverse engineering and material property testing was used. The foot analysis incorporated ground reaction forces measurement, motion analysis and strain gauge analysis. For the material model determination, non-destructive laboratory testing and its FE simulation was used. A new, realistic way of load application is presented along with a detailed investigation of stress distribution in the load-bearing components of the prosthesis. A novel approach for numerical and experimental agreement determination was introduced. This showed differences in the strain on the pylon between the experimental and the numerical model within 30% for the anteroposterior bending and up to 25% for the compression. The highest von Mises stresses were found on the foot-pylon connecting component at toe off. Peak stress of 216MPa occurred on the posterior adjusting screw and maximum stress of 156MPa was found at the neck of the male pyramid.

  15. DLR-F6复杂组合体跨声速阻力计算研究%Study of transonic drag computation on the DLR-F6 complex configurations

    Institute of Scientific and Technical Information of China (English)

    张宏; 颜洪

    2013-01-01

    The accuracy of the drag prediction was investigated by simulating the transonic flow fields around the DLR-F6 wing-body (WB) and wing-body-nacelle-pylon (WBNP) configurations. The computations were performed using fully turbulence boundary-layer and fixed position transition boundary-layer respectively. Multiple sets of grids with different densities were then employed. The drag, drag increments by adding the nacelle and the pylon and the effects of grid and transition were also estimated. The results show that grid refinement leads to convergent results for two configurations, and the predicted surface pressure distributions on the wing and nacelle are in agreement with the experimental data. When comparing the experiment data, the predicted incremental drag was over estimated by about 3 drag counts, 0.000 3, but better than the results obtained by using other software. The computed results show that grid refinement had little effect on the wall surface pressure distributions, but obvious effect on drag, especially the pressure drag. Relative to the whole turbulence model, transition had obvious effect on drag, particularly on friction drag, but almost no effect on nacelle/pylon induced incremental drag.%为了考察阻力预测的准确性,评估挂架/吊舱引起的阻力增量,分析网格和转捩对阻力及阻力增量的影响,采用不同密度网格,对DLR-F6翼/身和翼/身/挂/舱组合体跨声速流场进行了全湍流和固定转捩2种方式的数值模拟.翼/身和翼/身/挂/舱组合体均得到了网格收敛性结果,机翼表面和吊舱表面压力分布与实验数据吻合良好.预测的阻力增量高出实验数据0.0003,优于其他软件的结果.网格细分对壁面压力分布影响较小,对阻力尤其是压差阻力影响较大;相对于全湍流,转捩对阻力尤其是摩擦阻力影响较大,对挂架/吊舱引起的阻力增量几乎没有影响.

  16. Summary of Data from the Sixth AIAA CFD Drag Prediction Workshop: CRM Cases 2 to 5

    Science.gov (United States)

    Tinoco, Edward N.; Brodersen, Olaf P.; Keye, Stefan; Laflin, Kelly R.; Feltrop, Edward; Vassberg, John C.; Mani, Mori; Rider, Ben; Wahls, Richard A.; Morrison, Joseph H.; hide

    2017-01-01

    Results from the Sixth AIAA CFD Drag Prediction Workshop Common Research Model Cases 2 to 5 are presented. As with past workshops, numerical calculations are performed using industry-relevant geometry, methodology, and test cases. Cases 2 to 5 focused on force/moment and pressure predictions for the NASA Common Research Model wing-body and wing-body-nacelle-pylon configurations, including Case 2 - a grid refinement study and nacelle-pylon drag increment prediction study; Case 3 - an angle-of-attack buffet study; Case 4 - an optional wing-body grid adaption study; and Case 5 - an optional wing-body coupled aero-structural simulation. The Common Research Model geometry differed from previous workshops in that it was deformed to the appropriate static aeroelastic twist and deflection at each specified angle-of-attack. The grid refinement study used a common set of overset and unstructured grids, as well as user created Multiblock structured, unstructured, and Cartesian based grids. For the supplied common grids, six levels of refinement were created resulting in grids ranging from 7x10(exp 6) to 208x10(exp 6) cells. This study (Case 2) showed further reduced scatter from previous workshops, and very good prediction of the nacelle-pylon drag increment. Case 3 studied buffet onset at M=0.85 using the Medium grid (20 to 40x10(exp 6) nodes) from the above described sequence. The prescribed alpha sweep used finely spaced intervals through the zone where wing separation was expected to begin. Although the use of the prescribed aeroelastic twist and deflection at each angle-of-attack greatly improved the wing pressure distribution agreement with test data, many solutions still exhibited premature flow separation. The remaining solutions exhibited a significant spread of lift and pitching moment at each angle-of-attack, much of which can be attributed to excessive aft pressure loading and shock location variation. Four Case 4 grid adaption solutions were submitted. Starting

  17. A comprehensive vibration analysis of a coupled rotor/fuselage system

    Science.gov (United States)

    Yeo, Hyeonsoo

    A comprehensive vibration analysis of a coupled rotor/fuselage system for a two-bladed teetering rotor using finite element methods in space and time is developed which incorporates consistent rotor/fuselage structural, aerodynamic, and inertial couplings and a modern free wake model. A coordinate system is developed to take into account a teetering rotor's unique characteristics, such as teetering motion and undersling. Coupled nonlinear periodic blade and fuselage equations are transformed to the modal space in the fixed frame and solved simultaneously. The elastic line and detailed 3-D NASTRAN finite element models of the AH-1G helicopter airframe from the DAMVIBS program are integrated into the elastic rotor finite element model. Analytical predictions of rotor control angles, blade loads, hub forces, and vibration are compared with AH-1G Operation Load Survey flight test data. The blade loads predicted by present analysis show generally fair agreement with the flight test data, especially blade chord bending moment estimation shows good agreement. Calculated 2/rev vertical vibration levels at pilot seat show good correlation with the flight test data both in magnitude and phase, but 4/rev vibration levels show fair correlation only in magnitude. Lateral vibration results show more disagreement than vertical vibration results. Pylon flexibility effect is essential in the two-bladed teetering rotor vibration analysis. The pylon flexibility increases the first lag frequency by about 14%, and decreases 2/rev longitudinal and lateral hub forces by more than half. Rotor/fuselage coupling reduces 2/rev vertical and lateral vibration levels by 60% to 70% and has a small effect on 4/rev vibration levels. Modeling of difficult components (secondary structures, doors/panels, etc) is essential in predicting airframe natural frequencies. Refined aerodynamics such as free wake and unsteady aerodynamics have an important role in the prediction of vibration. For example, free

  18. 郑州市解放路跨线桥主桥设计与施工%Design and Construction of Main Bridge of Jiefang Road Overpass Bridge in Zhengzhou City

    Institute of Scientific and Technical Information of China (English)

    申国朝

    2012-01-01

    The main bridge of the Jiefang Road Overpass Bridge in Zhengzhou City is a cable-stayed bridge with twin pylons, single cable plane and with span arrangement (106 + 248 + 106) m and the bridge employs the structural system of rigid fixity of its pylons and main girder. The main girder of the bridge is of the prestressed concrete triple-cell single box of quasi-triangle section and has a 62 m long variable width portion at the side span on the west side. On both sides of a pylon, 15 pairs of stay cables made up of the low relaxation and high-strength galvanized parallel steel wires are arranged. The pylons are the concrete solid single-column ones of H-shape sections and the main piers are the vase shape hollow reinforced concrete structures supported on the frictional group bored pile foundations. The software Bridge Doctor V3. 03, MIDAS Civil and ANSYS were used to respectively build the plane finite element model for the bridge and the plane link and spatial plate-shell finite element models for the variable width portion. With these models, the global static force of the bridge and the force conditions of the portion were analyzed. In addition, a 1: 4 model for the variable width portion was also designed and made to carry out the model test. The results of the finite element analysis and model test showed that the force conditions of various parts of the bridge could meet the requirements in the codes. The part of the bridge spanning the passenger dedicated railway line on the east side was constructed by the rotation erection while the part of the bridge spanning the freight railway line on the west side was constructed by the covered form traveler.%郑州市解放路跨线桥主桥为双塔单索面斜拉桥,跨径布置为(106+248+106)m,采用塔、梁固结体系.该桥主梁为预应力混凝土单箱三室准三角形截面,西侧边跨设62 m长的变宽段.每个桥塔两侧布置15对斜拉索,斜拉索采用低松弛镀锌高强平行钢丝.桥塔采

  19. Rapid Parameterization Schemes for Aircraft Shape Optimization

    Science.gov (United States)

    Li, Wu

    2012-01-01

    A rapid shape parameterization tool called PROTEUS is developed for aircraft shape optimization. This tool can be applied directly to any aircraft geometry that has been defined in PLOT3D format, with the restriction that each aircraft component must be defined by only one data block. PROTEUS has eight types of parameterization schemes: planform, wing surface, twist, body surface, body scaling, body camber line, shifting/scaling, and linear morphing. These parametric schemes can be applied to two types of components: wing-type surfaces (e.g., wing, canard, horizontal tail, vertical tail, and pylon) and body-type surfaces (e.g., fuselage, pod, and nacelle). These schemes permit the easy setup of commonly used shape modification methods, and each customized parametric scheme can be applied to the same type of component for any configuration. This paper explains the mathematics for these parametric schemes and uses two supersonic configurations to demonstrate the application of these schemes.

  20. Evaluation of 3 numerical methods for propulsion integration studies on transonic transport configurations

    Science.gov (United States)

    Yaros, S. F.; Carlson, J. R.; Chandrasekaran, B.

    1986-01-01

    An effort has been undertaken at the NASA Langley Research Center to assess the capabilities of available computational methods for use in propulsion integration design studies of transonic transport aircraft, particularly of pylon/nacelle combinations which exhibit essentially no interference drag. The three computer codes selected represent state-of-the-art computational methods for analyzing complex configurations at subsonic and transonic flight conditions. These are: EULER, a finitie volume solution of the Euler equation; VSAERO, a panel solution of the Laplace equation; and PPW, a finite difference solution of the small disturbance transonic equations. In general, all three codes have certain capabilities that allow them to be of some value in predicting the flows about transport configurations, but all have limitations. Until more accurate methods are available, careful application and interpretation of the results of these codes are needed.

  1. Evaluation of three numerical methods for propulsion integration studies on transonic transport configurations

    Science.gov (United States)

    Yaros, Steven F.; Carlson, John R.; Chandrasekaran, Balasubramanyan

    1986-01-01

    An effort has been undertaken at the NASA Langley Research Center to assess the capabilities of available computational methods for use in propulsion integration design studies of transonic transport aircraft, particularly of pylon/nacelle combinations which exhibit essentially no interference drag. The three computer codes selected represent state-of-the-art computational methods for analyzing complex configurations at subsonic and transonic flight conditions. These are: EULER, a finite volume solution of the Euler equation; VSAERO, a panel solution of the Laplace equation; and PPW, a finite difference solution of the small disturbance transonic equations. In general, all three codes have certain capabilities that allow them to be of some value in predicting the flows about transport configurations, but all have limitations. Until more accurate methods are available, careful application and interpretation of the results of these codes are needed.

  2. Applying a New Parallelized Version of PSO Algorithm for Electrical Power Transmission

    Science.gov (United States)

    Zemzami, M.; Makhloufi, A.; Elhami, N.; Elhami, A.; Itmi, M.; Hmina, N.

    2017-06-01

    In this paper, the optimization of an electric power transmission material is presented giving specific consideration on material configuration and characteristics. The nature of electric power transmission networks makes it hard to manage. Thus, giving need for optimization. So the problem of optimization of electric power transmission as considered in this paper is improving the performance and reliability of the electricity pylon; the objective is to maximize resistance to load while reducing material usage and cost. For this purpose, we suggest a new version of PSO algorithm that allows the amelioration of its performance by introducing its parallelization associated to the concept of evolutionary neighborhoods. According to the experimental results, the proposed method is effective and outperforms basic PSO in terms of solution quality, accuracy, constraint handling, and time consuming.

  3. Calibration of solid state nuclear track detector CR-39 for radon measurements

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Marcia Pires de; Martins, Elaine Wirney [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: mpcampos@ipen.br

    2007-07-01

    Solid state nuclear track detectors (SSNTD) are widely used for radon measurements and CR-39 is one of the most popular SSNTD. In this work it was determined the calibration factor for radon concentration measurements through the passive method with CR-39 detectors. The detectors were put in a proper device (an adapted Lucas cell) and exposed to the standard radon concentration through the Pylon Model RN-150 flow through radon gas source. After exposure, the detectors were etched for 5.5 hours in a KOH solution at 80 deg C in a bath at a constant temperature. The track density was read in an Axiolab-Zeiss optical microscope, with nominal magnification of X10 connected to a video camera and to a personal computer. The calibration factor was obtained through the relation between standard radon concentration, track density and exposure time. (author)

  4. Jay L. King, Joseph D. Huxman, and Orion D. Billeter Assist Pilot Milt Thompson into the M2-F2 Attac

    Science.gov (United States)

    1966-01-01

    NASA research pilot Milt Thompson is helped into the cockpit of the M2-F2 lifting body research aircraft at NASA's Flight Research Center (now the Dryden Flight Research Center). The M2-F2 is attached to a wing pylon under the wing of NASA's B-52 mothership. The flight was a captive flight with the pilot on-board. Milt Thompson flew in the lifting body throughout the flight, but it was never dropped from the mothership. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft

  5. Aerodynamic and acoustic effects of eliminating core swirl from a full scale 1.6 stage pressure ratio fan (QF-5A)

    Science.gov (United States)

    Woodward, R. P.; Acker, L. W.; Stakolich, E. G.

    1978-01-01

    Fan QF-5A was a modification of fan QF-5 which had an additional core stator and adjusted support struts to turn the core exit flow from a 30 deg swirl to the axial direction. This modification was necessary to eliminate the impingement of the swirling core flow on the axial support pylon of the NASA-Lewis Quiet Fan Facility that caused aerodynamic, acoustic and structural problems with the original fan stage at fan speeds greater than 85 percent of design. The redesigned fan QF-5A did obtain the design bypass ratio with an increased core airflow suggesting that the flow problem was resolved. Acoustically, the redesigned stage showed a low frequency broadband noise reduction compared to the results for fan QF-5 at similar operating conditions.

  6. Approach for long term environmental parameters monitoring process using data acquisition devices and high level applications for data processing

    Science.gov (United States)

    Croitoru, Bogdan; Boca, Loredana; Abrudean, Mihail; Joldes, Remus

    2010-11-01

    Present paper describes a long term monitoring process of few environmental parameters for evaluating green energy potential (wind energy and solar energy) of a small geographical area (~ 32 km2). The monitoring approach presented in this paper consists in: real-time data acquisition process using two real-time data acquisition devices (DAQ); a wireless network used for long distance data transmission in order to send all acquired data to a remote location for processing; Virtual Instrument (VI's) applications used for controlling data acquisition devices and the acquisition process; a network protocol analyzer used for a detailed analysis of the communication protocols and data packets; the management of the huge volume of sensor data by using a high level software application; long term sensor monitoring using a complex graphic software application. The measured environment parameters are the following: wind speed, wind direction, temperature, sun intensity and illumination, steel pylon vibrations on three axes.

  7. Construction techniques of super-length main cable of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Shen Liangcheng; Liang Jinda

    2011-01-01

    Taizhou Bridge is a highway three-pylon two-span bridge with span arrangement of 1 080 m + 1 080 m and the length of the main cable is more than 3 100 m. It is the longest cable in China. As the erection of the main cable needs to cross over three towers and the cables undulate acutely, general problems like the twist, spread and swell of strands and shedding of the zinc coating are prone to arise, which make it difficult to guarantee the quantity of cable traction construction. In this paper, the hauling, shaping and saddling of strands and sag adjusting are illustrated in detail and how to execute the refined construction control to guarantee the erection quality is also covered.

  8. 同向回转拉索锚固体系斜拉索施工技术%Construction Techniques for Stay Cables Provided with Isodirectionally Turning Stay Cable Anchor System

    Institute of Scientific and Technical Information of China (English)

    李景丰; 周伟明

    2015-01-01

    安徽五河定淮淮河特大桥主桥为独塔双索面混合梁斜拉桥,跨径布置为246 m+125 m,该桥采用钢绞线斜拉索,斜拉索采用同向回转拉索锚固体系,即斜拉索穿过桥面一侧锚具,绕过桥塔后锚回到桥面另一侧锚具,形成同一对编号斜拉索。同向回转拉索锚固体系由钢绞线拉索系统、夹持型大转角鞍座锚索系统及主梁锚拉板锚索系统3部分组成。斜拉索采用三角提升原理安装,利用穿索机推送及卷扬机牵引将主梁一侧的钢绞线送入HDPE外套管中,穿过鞍座后,通过穿索机推送及另外一台卷扬机牵引钢绞线回到主梁另一侧锚固区,钢绞线穿索就位后,采用单股对称张拉法进行斜拉索张拉,张拉到位后进行封锚处理。%The main bridge of Dinghuai Huaihe River Bridge in Wuhe ,Anhui is a hybrid girder cable‐stayed bridge with a single pylon ,double cable planes and with span arrangement 246 m+125 m .The stay cables of the bridge are the steel wire strand cables and are anchored by the isodi‐rectionally turning stay cable anchor system .That is ,a full long stay cable of the bridge is firstly extended out of its anchor at one side of the bridge deck and is led to the saddle in the pylon ,then the cable transversely turns around at the saddle and is finally led downwards and extended into the anchor at the other side of the deck to consequently form a pair of the cables of the same numbe‐ring .The isodirectionally turning stay cable anchor system is comprised of 3 parts of the stay cable system ,large turning angle clamping saddle anchor in the pylon and the anchor tensile plate anchor in the main girder .The stay cables of the bridge are installed ,using the principle of the triangle‐shape lifting .By the delivering of the cable threading machine and the hauling of the winch ,the steel wire strands of a cable on one side of the deck are led into the HDPE sheaths and the sheathed

  9. Modeling of cable vibration effects of cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The analysis of dynamic responses of cable-stayed bridges subjected to wind and earthquake loads generallyconsiders only the motions of the bridge deck and pylons. The influence of the stay cable vibration on the responses of the bridgeis either ignored or considered by approximate procedures. The transverse vibration of the stay cables, which can be significant insome cases, are usually neglected in previous research. In the present study, a new three-node cable element has been developed tomodel the transverse motions of the cables. The interactions between the cable behavior and the other parts of the bridgesuperstructure are considered by the concept of dynamic stiffness. The nonlinear effect of the cable caused by its self-weight isincluded in the formulation. Numerical examples are presented to demonstrate the accuracy and efficiency of the proposed model.The impact of cable vibration behavior on the dynamic characteristics of cable-stayed bridges is discussed.

  10. Roughness receptivity studies in a 3-D boundary layer - Flight tests and computations

    Science.gov (United States)

    Carpenter, Andrew L.; Saric, William S.; Reed, Helen L.

    The receptivity of 3-D boundary layers to micron-sized, spanwise-periodic Discrete Roughness Elements (DREs) was studied. The DREs were applied to the leading edge of a 30-degree swept-wing at the wavelength of the most unstable disturbance. In this case, calibrated, multi-element hotfilm sensors were used to measure disturbance wall shear stress. The roughness height was varied from 0 to 50 microns. Thus, the disturbance-shear-stress amplitude variations were determined as a function of modulated DRE heights. The computational work was conducted parallel to the flight experiments. The complete viscous flowfield over the O-2 aircraft with the SWIFT model mounted on the port wing store pylon was successfully modeled and validated with the flight data. This highly accurate basic-state solution was incorporated into linear stability calculations and the wave growth associated with the crossflow instability was calculated.

  11. The application of digital particle image velocimetry (DPIV) to transonic flows

    Science.gov (United States)

    Bryanston-Cross, P. J.; Judge, T. R.; Quan, C.; Pugh, G.; Corby, N.

    The paper is an extension to earlier PIV work published in Progress in Aerospace Science Vol. 27, pp237-265. 1990. DPIV (Digital Particle Image Velocimetry) measurements have been made at transonic speeds using a new method of both digitally capturing and visualising high speed flow-fields. It has provided a quantitative whole field image of the transonic flow. The area of interest for this test was of the wing/pylon/nacelle/inboard gully region of a 5.7% scale model wing and engine combination. The measurements show velocity and flow angle changes in this region, to a measurement accuracy of 4%, made at an optical stand off distance of 0.5 m.

  12. A grid interfacing zonal algorithm for three-dimensional transonic flows about aircraft configurations

    Science.gov (United States)

    Atta, E. H.; Vadyak, J.

    An efficient grid interfacing zonal algorithm has been developed for computing the transonic flow field about three-dimensional multicomponent configurations. The algorithm uses the full-potential formulation and the fully-implicit approximate factorization scheme (AF2). The flow field solution is computed using a component adaptive grid approach in which separate grids are employed for the individual components in the multicomponent configuration, where each component grid is optimized for a particular geometry. The component grids are allowed to overlap, and flow field information is transmitted from one grid to another through the overlap region. An overlapped-grid scheme is implemented for a wing and a wing/pylon/nacelle configuration. Numerical results show that the present algorithm is stable, accurate, and can be used effectively to compute the flow field about complex configurations.

  13. Drag/thrust analysis of jet-propelled transonic transport aircraft; definition of physical drag components

    Energy Technology Data Exchange (ETDEWEB)

    Destarac, D. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France); Van der Vooren, J. [Senior research scientist, retired, Hoekse Waard (Netherlands)

    2004-09-01

    Drag/thrust analysis of jet-propelled transonic transport aircraft on the basis of calculated viscous flow is discussed. Unique definitions for viscous drag plus wave drag and for induced drag are established. The concept of additive through flow drag is introduced. Drag/thrust bookkeeping is given attention. All drag components can be calculated in the flow region adjacent to the aircraft, where numerical accuracy is expectingly highest. Uniform handling of complex aircraft configurations is brought within reach. Near-field/far-field drag balances are exact. Computational aspects are discussed, in particular the elimination of spurious drag sources. Numerical examples are given for a wing-body and for a wing-body-pylon-nacelle configuration. In either case, the spurious drag sources are eliminated. Acceptable agreement is obtained for the total drag in the first case, and for the installation drag in the second case. Extension of the analysis presented to propeller-driven transport aircraft is straightforward. (author)

  14. Studies on aerodynamic interferences between the components of transport airplane using unstructured Navier-Stokes simulations

    Energy Technology Data Exchange (ETDEWEB)

    Wang, G.; Ye, Z. [Northwestern Polytechnical Univ., National Key Lab. of Aerodynamic Design and Research, Xi' an (China)]. E-mail: wanggang@nwpu.edu.cn; yezy@nwpu.edu.cn

    2005-07-01

    It is well known that the aerodynamic interference flows widely exist between the components of conventional transport airplane, for example, the wing-fuselage juncture flow, wing-pylon-nacelle flow and tail-fuselage juncture flow. The main characteristic of these aerodynamic interferences is flow separation, which will increase the drag, reduce the lift and cause adverse influence on the stability and controllability of the airplane. Therefore, the modern civil transport designers should do their best to eliminate negative effects of aerodynamic interferences, which demands that the aerodynamic interferences between the aircraft components should be predicted and analyzed accurately. Today's CFD techniques provide us powerful and efficient analysis tools to achieve this objective. In this paper, computational investigations of the interferences between transport aircraft components have been carried out by using a viscous flow solver based on mixed element type unstructured meshes. (author)

  15. Aerodynamic Optimization of an Over-the-Wing-Nacelle-Mount Configuration

    Directory of Open Access Journals (Sweden)

    Daisuke Sasaki

    2011-01-01

    Full Text Available An over-the-wing-nacelle-mount airplane configuration is known to prevent the noise propagation from jet engines toward ground. However, the configuration is assumed to have low aerodynamic efficiency due to the aerodynamic interference effect between a wing and a nacelle. In this paper, aerodynamic design optimization is conducted to improve aerodynamic efficiency to be equivalent to conventional under-the-wing-nacelle-mount configuration. The nacelle and wing geometry are modified to achieve high lift-to-drag ratio, and the optimal geometry is compared with a conventional configuration. Pylon shape is also modified to reduce aerodynamic interference effect. The final wing-fuselage-nacelle model is compared with the DLR F6 model to discuss the potential of Over-the-Wing-Nacelle-Mount geometry for an environmental-friendly future aircraft.

  16. Operation UPSHOT-KNOTHOLE. Report to the Test Director Aircraft Participation, Nevada Proving Grounds, March-June 1953

    Science.gov (United States)

    1982-06-04

    wing (leading edge) 30 IS Right pylon rack Right wing tip 9 Right wing tip tank 750 50 7 Right side turbina 150 150 IS Right horizontal stabilizer...and one B-29 to obtain 10 particulate samples, nine snap samples, and one gas sample from a B-29. 45 A minimum fraction of 2 * 10’* for a 35-kt...2 ■ gas * 11 § • a « cl Ä 9> «So ■2 « a -3 g s o " 2 c iJ 11 B a 3 1 ’O llill ^d •S 2 a "? § >> ■- a Ti ŗ i Si a 91 36 "s i n

  17. From a 32 m2 system with 90 CPV modules to a 105 m2 system with 12 CPV modules - Soitec's new CPV system CX-S530

    Science.gov (United States)

    Gombert, Andreas; Wanka, Sven; Gerster, Eckart; van Riesen, Sascha; Neubauer, Martin; Lange, Gerrit; Hamidi, Amir; Burke, Thomas; Stör, Jakob; Aipperspach, Wolfgang; Taliercio, Cecile; Mader, Lucas; Valli, Alessandro; Ziegler, Martin; Hepp, Stefan; Heile, Inka; Gerstmaier, Tobias; Haarburger, Karl-Friedrich

    2012-10-01

    In 2008, Soitec started to launch a 32m2 CPV system which included 90 modules per tracker. In order to realize the fast installation of multi-MW power plants the CPV module CX-M500 with an aperture area of 7,84 m2 was developed together with the new tracker CX-T030 which is optimized for carrying 12 of the new modules. This paper gives an overview over the evolution of this CPV system. The module is based on components of the field proven earlier Concentrix module generations. The tracker is a classical pylon type with two AC motor powered slewing ring drives. A new control device was developed which uses the power-optimized sun tracking algorithm. The major development steps and their results are presented.

  18. CFD Predictions for Transonic Performance of the ERA Hybrid Wing-Body Configuration

    Science.gov (United States)

    Deere, Karen A.; Luckring, James M.; McMillin, S. Naomi; Flamm, Jeffrey D.; Roman, Dino

    2016-01-01

    A computational study was performed for a Hybrid Wing Body configuration that was focused at transonic cruise performance conditions. In the absence of experimental data, two fully independent computational fluid dynamics analyses were conducted to add confidence to the estimated transonic performance predictions. The primary analysis was performed by Boeing with the structured overset-mesh code OVERFLOW. The secondary analysis was performed by NASA Langley Research Center with the unstructured-mesh code USM3D. Both analyses were performed at full-scale flight conditions and included three configurations customary to drag buildup and interference analysis: a powered complete configuration, the configuration with the nacelle/pylon removed, and the powered nacelle in isolation. The results in this paper are focused primarily on transonic performance up to cruise and through drag rise. Comparisons between the CFD results were very good despite some minor geometric differences in the two analyses.

  19. The effect of prosthetic alignment on relative limb loading in persons with trans-tibial amputation: a preliminary report.

    Science.gov (United States)

    Pinzur, M S; Cox, W; Kaiser, J; Morris, T; Patwardhan, A; Vrbos, L

    1995-11-01

    The prosthetic sockets of 14 independent persons with unilateral trans-tibial (BK) amputation were mounted on an adjustable alignment pylon. Vertical ground reaction forces were recorded in neutral prosthetic alignment and in 10 degrees of prosthetic socket varus, valgus, flexion, and extension. Stance phase time, peak vertical ground reaction force, and impulse were all found to be increased on the sound limb when compared to the amputated residual limb. Significant differences were found in stance phase time and peak vertical ground reaction force when comparing malaligned with neutrally aligned prosthetic limbs. Significant differences were also seen in impulse between neutrally aligned and malaligned prosthetic limbs. The results suggest that prosthetic malalignment in persons with trans-tibial amputation leads to increased loading of the contralateral limb.

  20. The Carlina-type diluted telescope: Stellar fringes on Deneb

    CERN Document Server

    Coroller, H Le; Hespeels, F; Arnold, L; Andersen, T; Deram, P; Ricci, D; Berio, P; Blazit, A; Clausse, J-M; Guillaume, C; Meunier, J-P; Regal, X; Sottile, R

    2014-01-01

    Context. The performance of interferometers has largely been increased over the last ten years. But the number of observable objects is still limited due to the low sensitivity and imaging capability of the current facilities. Studies have been done to propose a new generation of interferometers. Aims. The Carlina concept studied at the Haute-Provence Observatory consists in an optical interferometer configured as a diluted version of the Arecibo radio telescope: above the diluted primary mirror made of fixed co-spherical segments, a helium balloon or cables suspended between two mountains and/or pylons, carries a gondola containing the focal optics. This concept does not require delay lines. Methods. Since 2003, we have been building a technical demonstrator of this diluted telescope. The main goals of this project were to find the opto-mechanical solutions to stabilize the optics attached under cables at several tens of meters above the ground, and to characterize this diluted telescope under real condition...

  1. Etude de la stabilite d'un avion BWB (Blended Wing Body) de 200 passagers

    Science.gov (United States)

    Legros, Clement

    The Blended Wing Body (BWB) is a type of innovative aircraft, based on the flying wing concept. This new type of airplane shows several advantages compared to the conventional airplanes : economy of fuel, reduction of the weight of the structure, reduction of the noise and less impact on the environment, increased payload capacity. However, this kind of aircraft has a lack of stability due to the absence of vertical tail. Several studies of stability were already realized on reduced size models of BWB, but there is no study on a 200 passengers BWB. That's why, the main objective of this present study is to integrate the engines and theirs pylons into the existing conceptual design of the BWB to analyze of their impact on its static and dynamic stability over the flight envelope. The conception of the BWB was realized with the platform of design CEASIOM. The airplane, the engines and theirs pylons were obtained in the geometrical module AcBuilder of CEASIOM. The various aerodynamic coefficients are calculated thanks to Tornado program. These coefficients allow realizing the calculations of stability, in particular with the longitudinal and lateral matrices of stability. Afterward, the BWB flight envelope is created based on aeronautical data of a similar airplane, the Airbus A320. From this flight envelope, we get back several thousand possible points of flight. The last step is to check the static and dynamic stability, using the longitudinal and lateral matrices of stability and the Flying Qualities Requirements, for every point of flight. To validate our study of stability, the already existing studies of stability of the Boeing 747 will be used and compared with our model.

  2. Generation After Next Propulsor Research: Robust Design for Embedded Engine Systems

    Science.gov (United States)

    Arend, David J.; Tillman, Gregory; O'Brien, Walter F.

    2012-01-01

    The National Aeronautics and Space Administration, United Technologies Research Center and Virginia Polytechnic and State University have contracted to pursue multi-disciplinary research into boundary layer ingesting (BLI) propulsors for generation after next environmentally responsible subsonic fixed wing aircraft. This Robust Design for Embedded Engine Systems project first conducted a high-level vehicle system study based on a large commercial transport class hybrid wing body aircraft, which determined that a 3 to 5 percent reduction in fuel burn could be achieved over a 7,500 nanometer mission. Both pylon-mounted baseline and BLI propulsion systems were based on a low-pressure-ratio fan (1.35) in an ultra-high-bypass ratio engine (16), consistent with the next generation of advanced commercial turbofans. An optimized, coupled BLI inlet and fan system was subsequently designed to achieve performance targets identified in the system study. The resulting system possesses an inlet with total pressure losses less than 0.5%, and a fan stage with an efficiency debit of less than 1.5 percent relative to the pylon-mounted, clean-inflow baseline. The subject research project has identified tools and methodologies necessary for the design of next-generation, highly-airframe-integrated propulsion systems. These tools will be validated in future large-scale testing of the BLI inlet / fan system in NASA's 8 foot x 6 foot transonic wind tunnel. In addition, fan unsteady response to screen-generated total pressure distortion is being characterized experimentally in a JT15D engine test rig. These data will document engine sensitivities to distortion magnitude and spatial distribution, providing early insight into key physical processes that will control BLI propulsor design.

  3. 轴对称结构RBCC发动机超燃模态试验和数值模拟%Experiment and numerical simulation on scramjet mode of axisymmetric RBCC engine

    Institute of Scientific and Technical Information of China (English)

    汤祥; 何国强; 秦飞; 刘佩进; 潘科玮

    2012-01-01

    To study the ignition and combustion performance of axisymmetric RBCC engine in scramjet mode, experiments were carried out on the direct-connected test-bed. The combination of the strut-rocket and the injection of pylons was adopted as the way of ignition and flame holding,and the injection schemes of the fuel were investigated. The results of the experiment and numerical simulation indicate that this way of ignition could achieve reliable ignition and steady combustion. Using the manner of multiple injections could fully make use of oxygen and achieve sufficient combustion, but the proportion of the fuel injection should be controlled. By using double pylons,the mixing between the fuel and central air is promoted to increase the combustion efficiency and obtain good combustion performance.%为研究轴对称结构RBCC发动机超燃模态下的点火和燃烧性能,进行了地面直连试验.采用中心支板火箭与小支板组喷注相结合的方式作为点火和火焰稳定方式,并对燃料喷注方案进行了研究.试验与数值模拟结果表明,采用这种点火方式能实现轴对称结构RBCC发动机的可靠点火和稳定燃烧.二次燃料采取多级喷注的方式能充分利用流道中的氧气,实现较充分的燃烧,但应控制燃料喷注比例.双支板组的加入,能促进燃料与中心空气流的充分掺混,提升燃烧效率,获得较优的燃烧性能.

  4. 外挂物干扰流场特性数值仿真研究%Numerical Simulation and Research on Aerodynamic Characteristics of Interacting Flow Field past External Store

    Institute of Scientific and Technical Information of China (English)

    王立强; 董国国

    2012-01-01

    飞行器研制中对于带外挂物的复杂外形气动特性分析研究一直是个难点,对外挂物与挂架不同缝隙的复杂机翼-挂架-外挂物组合外形采用结构重叠网格数值方法,快捷高质地完成了网格生成,通过求解带有k-e湍流模型的Navier-Stokes方程组,得到多个计算工况下的绕流外流场,分析了外挂物在不同工况下的气动特性,结果表明,CFD数值方法可方便快捷地对复杂干扰流场进行数值计算,可为飞行器相关设计提供技术支持.%It is always a barrier to analyze aerodynamic characteristic of complicated shape with stores in aircraft developing. In this paper,the complicated geometry shape of wing- pylon- store of different gap of store and pylon, overlapping structured grid is used which can work well in such case. Thorough solving Navier- Stokes equations team with k- e turbulent model,the outer flow field around the store is reached. The aerodynamic characteristic is analyzed in some conditions, and the results display that with the numerical method, complicated interacting flow field can be numerically simulated expediently and efficiently, which can give some technical contribution to design of aircraft.

  5. Application of Aerodynamic Shape Deformation based on NURBS Surface%NURBS曲面在气动外形变形中的应用

    Institute of Scientific and Technical Information of China (English)

    马晓永; 张彦军; 雷武涛

    2014-01-01

    针对翼吊布局飞机复杂气动外形,建立了基于样条(NURBS,非均匀有理B样条)曲面和曲面叠加技术的曲面变形方法。在对样条曲线性质分析的基础上,以DLR-F6飞机为实例,对其机翼翼根、短舱挂架局部进行曲面网格变形,结果表明该方法能有效表述其复杂几何外形及型面变化特性,并且具有较好的局域性、可控性和光滑性。该方法可有效应用于吊舱挂架等复杂气动外形的建模、表面网格变形及气动外形优化设计等。%A free deformation method based on the B-Spline (NURBS, Non-Uniform Rational B-Spline) and surface superposition technique was presented for complex aerodynamic shape such as wing mounted nacelle-pylon conifguration. The characteristic of parameters were analyzed with B-Spline curves case, and the application instances of surface grids deformation on wing and pylon of DLR-F6 plane shows that the method could describe complex surfaces and its deformation characteristic effectively, the control parameter only change its local surface, and it is easy to carry out. The method is feasible and applicable to model representation, surface grids deformation and aerodynamic shape optimization etc.

  6. Development of a residuum/socket interface simulator for lower limb prosthetics.

    Science.gov (United States)

    McGrath, Michael Paul; Gao, Jianliang; Tang, Jinghua; Laszczak, Piotr; Jiang, Liudi; Bader, Dan; Moser, David; Zahedi, Saeed

    2017-03-01

    Mechanical coupling at the interface between lower limb residua and prosthetic sockets plays an important role in assessing socket fitting and tissue health. However, most research lab-based lower limb prosthetic simulators to-date have implemented a rigid socket coupling. This study describes the fabrication and implementation of a lower limb residuum/socket interface simulator, designed to reproduce the forces and moments present during the key loading phases of amputee walking. An artificial residuum made with model bones encased in silicone was used, mimicking the compliant mechanical loading of a real residuum/socket interface. A 6-degree-of-freedom load cell measured the overall kinetics, having previously been incorporated into an amputee's prosthesis to collect reference data. The developed simulator was compared to a setup where a rigid pylon replaced the artificial residuum. A maximum uniaxial load of 850 N was applied, comparable to the peak vertical ground reaction force component during amputee walking. Load cell outputs from both pylon and residuum setups were compared. During weight acceptance, when including the artificial residuum, compression decreased by 10%, while during push off, sagittal bending and anterior-posterior shear showed a 25% increase and 34% decrease, respectively. Such notable difference by including a compliant residuum further highlighted the need for such an interface simulator. Subsequently, the simulator was adjusted to produce key load cell outputs briefly aligning with those from amputee walking. Force sensing resistors were deployed at load bearing anatomic locations on the residuum/socket interface to measure pressures and were compared to those cited in the literature for similar locations. The development of such a novel simulator provides an objective adjunct, using commonly available mechanical test machines. It could potentially be used to provide further insight into socket design, fit and the complex load

  7. Puente de Humber Gran Bretaña

    Directory of Open Access Journals (Sweden)

    Población Knappe, Eleuterio

    1981-03-01

    Full Text Available This article describes the building of the world's longest single- span hanging bridge (2,250 metres in the Humber estuary. The floor of this bridge, the main light of which Is 1,410 m, is formed by trapezoidal chestbeams made with 18 m long rigid sheets. This makes possible both economy of steel and a reduction In the dimensions of the cables, pylons and anchorage masses. The pylons, built of sliding formwork, consist of two 155 m high reinforced concrete hollow pillars.These pillars are joined by four horizontal struts. The construction of the Humber bridge allows the distances between both shores of the estuary to be cut and completes the motorway network in the area.

    Se describe en este artículo la construcción del puente colgado de tramo sencillo más largo del mundo (2.250 m en el estuario de Humber. El tablero de este puente, cuya luz principal es de 1.410 m, está formado por vigas-cajón trapezoidales realizadas mediante chapas rigidizadas de 18 m de longitud. De esta manera se obtiene una economía de acero así como una reducción en las dimensiones de los cables, pilonos y macizos de anclaje. Los pilonos, construidos con encofrado deslizante, se componen de dos pilares huecos de hormigón armado de 155 m de altura. Estos pilares están unidos por cuatro riostras horizontales. La construcción del puente de Humber permite acortar las distancias entre ambas orillas del estuario y completa la red de autopistas de la zona.

  8. B-52B Cockpit Instrument Panel

    Science.gov (United States)

    1996-01-01

    casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet. It is 156 feet long and has a wing span of 185 feet. The heaviest load it has carried was the No. 2 X-15 aircraft at 53,100 pounds. Project manager for the aircraft is Roy Bryant.

  9. 港珠澳大桥青州航道桥工程特点及关键技术%Engineering Characteristics and Key Techniques of Qingzhou Ship Channel Bridge of Hong Kong-Zhuhai-Macao Bridge

    Institute of Scientific and Technical Information of China (English)

    刘明虎; 孟凡超; 李国亮

    2013-01-01

    The Qingzhou Ship Channel Bridge of the Hong Kong-Zhuhai-Macao Bridge is a steel box girder cable-stayed bridge with double pylons and double cable planes.In the design of the bridge,a variety of the new materials,new techniques and new workmanships have been applied.In this paper,the engineering characteristics and key techniques of the bridge are summarized.On the bridge,the steel box girders of the same structural types of the adjacent non-navigable span bridges are fully used as the counterweight and on the outer side spans of the bridge,the stay cables are not installed.The arrangement of the bridge in such a way is well appropriate to the local conditions of the bridge site and has notable comprehensive advantage.The structural support system of the bridge is the three-way system that can ensure the structural performance of the whole bridge to be optimal.The pylons have the crisscross steel struts of the “Chinese Knot” configuration,which are connected with the concrete pylon columns via the connecting boxes in a combined force transmitting mode of “ compression-shear” and the performance of the steel struts and connection is safe and reliable.The foundations for the bridge are the composite piles of variable diameter steel pipes and together with the reinforced concrete in the steel pipes,the composite sections of the piles that are to jointly bear the loads and are cost-saving and rational are formed.The pier shafts are formed by the precast segments.The segments are installed at the site and are connected each other by the φ75 mm thick prestressing bars.The steel box girders are of the optimized streamlined flat sections topped with the orthotropic steel deck plates and the fatigue performance of the girders are quite superior.The stay cables are the ones made up of the parallel steel wires and having tensile strength of 1 860 MPa.%港珠澳大桥青州航道桥为双塔双索面钢箱梁斜拉桥,该桥设计采用了多项新材料、新技术

  10. B-52 Launch Aircraft in Flight

    Science.gov (United States)

    2001-01-01

    the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables the B-52 to carry research vehicles and test articles to be air-launched/dropped. Located on the right wing, between the inboard engine pylon and the fuselage, this wing pylon was subjected to extensive testing prior to its use. For each test vehicle the B-52 carried, minor changes were made to the launch-panel operator's station. Built originally by the Boeing Company, the NASA B-52 is powered by eight Pratt & Whitney J57-19 turbojet engines, each of which produce 12,000 pounds of thrust. The aircraft's normal launch speed has been Mach 0.8 (about 530 miles per hour) and its normal drop altitude has been 40,000 to 45,000 feet. It is 156 feet long and has a wing span of 185 feet.

  11. Turboelectric Distributed Propulsion in a Hybrid Wing Body Aircraft

    Science.gov (United States)

    Felder, James L.; Brown, Gerald V.; DaeKim, Hyun; Chu, Julio

    2011-01-01

    The performance of the N3-X, a 300 passenger hybrid wing body (HWB) aircraft with turboelectric distributed propulsion (TeDP), has been analyzed to see if it can meet the 70% fuel burn reduction goal of the NASA Subsonic Fixed Wing project for N+3 generation aircraft. The TeDP system utilizes superconducting electric generators, motors and transmission lines to allow the power producing and thrust producing portions of the system to be widely separated. It also allows a small number of large turboshaft engines to drive any number of propulsors. On the N3-X these new degrees of freedom were used to (1) place two large turboshaft engines driving generators in freestream conditions to maximize thermal efficiency and (2) to embed a broad continuous array of 15 motor driven propulsors on the upper surface of the aircraft near the trailing edge. That location maximizes the amount of the boundary layer ingested and thus maximizes propulsive efficiency. The Boeing B777-200LR flying 7500 nm (13890 km) with a cruise speed of Mach 0.84 and an 118100 lb payload was selected as the reference aircraft and mission for this study. In order to distinguish between improvements due to technology and aircraft configuration changes from those due to the propulsion configuration changes, an intermediate configuration was included in this study. In this configuration a pylon mounted, ultra high bypass (UHB) geared turbofan engine with identical propulsion technology was integrated into the same hybrid wing body airframe. That aircraft achieved a 52% reduction in mission fuel burn relative to the reference aircraft. The N3-X was able to achieve a reduction of 70% and 72% (depending on the cooling system) relative to the reference aircraft. The additional 18% - 20% reduction in the mission fuel burn can therefore be attributed to the additional degrees of freedom in the propulsion system configuration afforded by the TeDP system that eliminates nacelle and pylon drag, maximizes boundary

  12. Correlation between Helicobacter pylori infection and hemoglobin A1c expression%幽门螺杆菌感染与糖化血红蛋白表达相关性的研究进展

    Institute of Scientific and Technical Information of China (English)

    李伟; 杨桢; 黄德强; 吕农华

    2012-01-01

    Helicobacter pylori (H. pylori) is a gram-negative bacterium that is closely related with the patho-genesis of chronic gastritis, peptic ulcer, gastric carcinoma as well as many extra-gastrointestinal tract diseases such as coronary heart disease, iron deficiency anemia, idiopathic thrombocy-topenic purpura, and diabetes mellitus (DM). Hemoglobin Ale (HbAlc) level is useful in diagnosing and monitoring DM. Recent studies showed that H. pylori is involved in the up-reg-ulation of HbAlc level in DM patients through modulating the expression of leptin and ghrelin, whose interactions affect obesity, insulin sensitivity, glucose homeostasis and DM. Further studies on the association between H. pylori in- fection and HbAlc will certainly provide new prospects for early diagnosis and treatment of H. pylon-related DM and its complications.%幽门螺杆菌(Helicobacter pylo,H.pylon)是一种与胃黏膜疾病关系密切的革兰阴性菌,研究发现其与糖尿病、冠心病、缺铁性贫血、特发性血小板减少性紫癜等胃肠外疾病亦紧密相关,然而个中机制却仍不明确,糖化血红蛋白(hemoglobin A1c,HbA1c)是糖尿病(diabetes mellitus,DM)患者血糖水平长期监控的重要指标,研究发现,H.pylori感染阳性的DM患者外周血HbA1c水平较H.pylori阴性DM患者显著升高,这很有可能是H.pylori通过下调胃黏膜瘦素和脑肠肽的表达,造成宿主代谢紊乱和胰岛素抵抗而导致的.关于H.pylori和HbA1c关系的早期研究具有一定的局限性,更为全面、深入的研究势必为H.pylori感染相关性糖尿病的早期防治提供新的方向.

  13. 圆形燃烧室支板火箭超燃冲压发动机数值模拟%Numerical simulation of strut-rocket scramjet with circular combustor

    Institute of Scientific and Technical Information of China (English)

    秦飞; 何国强; 刘佩进; 李鹏飞

    2011-01-01

    For increasing the ability of ignition and flame holding of large scale scramjet, the strut-rocket scramjet is developed, which consists of main strut in isolator, strut rocket and circular combustor. The numerical simulation including multi-steps chemical mechanisms was developed to investigate the reactive flow characteristics for liquid hydrocarbon supersonic combustion in circular combustor strut-rocket scramjet which is combined with pylons and cavity. It is indicated that the combination of strut-rocket and pylons is the paramount mechanism for flame holding. The results show that the strut-rocket scramjet can provide robust ignition and combustion efficiency and wide operability for ambient liquid hydrocarbon fuel in large scale combnstor.%为了提高大尺寸超燃冲压发动机的掺混燃烧和火焰稳定能力,提出了以中心主支板和支板火箭进行点火和火焰稳定的超燃冲压发动机基本结构,采用轴对称的圆形燃烧室以及小支板和凹腔等混合增强方式,通过包含多步简化动力学的数值模拟方法,研究了支板、凹腔结构与圆形燃烧室的不同匹配关系.结果表明,隔离段中心主支板能有效提高燃料与空气的掺混度,支板火箭的富燃高温羽流在不同状态下均能实现可靠点火;圆形燃烧室结合多组小支板和凹腔能进一步增强燃料混合和高效燃烧.利用支板火箭与轴对称圆形燃烧室相结合能在较短燃烧室内实现高效燃烧,为将来开展大尺寸超燃冲压发动机燃烧技术研究奠定基础.

  14. The Carlina-type diluted telescope. Stellar fringes on Deneb

    Science.gov (United States)

    Le Coroller, H.; Dejonghe, J.; Hespeels, F.; Arnold, L.; Andersen, T.; Deram, P.; Ricci, D.; Berio, P.; Blazit, A.; Clausse, J.-M.; Guillaume, C.; Meunier, J. P.; Regal, X.; Sottile, R.

    2015-01-01

    Context. The performance of interferometers has been much increased over the past ten years. But the number of observable objects is still limited by the low sensitivity and imaging capability of the current facilities. Studies have been conducted with the aim to propose a new generation of interferometers. Aims: The Carlina concept studied at the Haute-Provence Observatory consists of an optical interferometer configured as a diluted version of the Arecibo radio telescope: above the diluted primary mirror made of fixed co-spherical segments, a helium balloon or cables that are suspended between two mountains and/or pylons carry a gondola containing the focal optics. This concept does not require delay lines. Methods: Since 2003, we have been building a technical demonstrator of this diluted telescope. The main goals of this project were to find opto-mechanical solutions to stabilize the optics attached to cables at several tens of meters above the ground, and to characterize this diluted telescope under real conditions. In 2012, we obtained metrology fringes, and co-spherized the primary mirrors within one micron accuracy. In 2013, we tested the whole optical train: servo loop, metrology, and the focal gondola. Results: We obtained stellar fringes on Deneb in September 2013. We here present the characteristics of these observations: quality of the guiding, signal-to-noise ratio reached, and possible improvements for a future system. Conclusions: By detecting fringes on Deneb, we confirm that the entire system conceptually has worked correctly. It also proves that when the primary mirrors are aligned using the metrology system, we can directly record fringes in the focal gondola, even in blind operation. It is an important step that demonstrates the feasibility of building a diluted telescope using cables strained between cliffs or pylons. Carlina, like the Multiple Mirror Telescope (MMT) or Large Binocular Telescope (LBT), could be one of the first members of a

  15. 大型客机发动机振动载荷传递特性研究%Exploring Wing-Mounted Engine Vibration Transmission for New Generation Airplanes with Turbofan Engines of High Bypass Ratio

    Institute of Scientific and Technical Information of China (English)

    陈熠; 贺尔铭; 扈西枝; 韩峰

    2012-01-01

    The use of turbofan engines of high bypass ratio has caused the low-frequency structure-borne noise. To investigate the medium and low frequency vibration transmission through wing structure to airframe, we introduce the double-beam dynamic model of a wing and build the "pylon-wing-airframe" dynamic half model of a full airplane, which takes into account the dynamics of an actual airplane. Sections 1 through 4 of the full paper explain the exploration mentioned in the title; their core consists of; ( 1) we use the vibration spectrum of the turbofan engines to calculate the vibration load of the airplane at each section of the airframe transmitted from wing to the air-frame , which provides the input data for estimating the noise level of the pressurized cabin; (2) through simulation , we identify the main path of engines' vibration transmission to the airframe; the simulation results, given in Figs. 6 and 7, and their analysis form, in our opinion, a useful preparation for pylon structure vibration reduction, engine vibration isolation mounting and the acoustic design inside the cabin.%高涵道比涡扇发动机的振动冲击频段向低频转移,使得飞机舱内噪声频率分布中的低频结构传递噪声变得更加突出.为了研究发动机振动载荷通过机翼向机身传递的中低频振动特性,文章针对真实客机的结构动力特性,创新地提出了机翼双梁动力学模型概念,建立了“吊架-机翼-机身”全机动力学有限元模型;基于发动机的振动载荷谱,分析了发动机振动通过机翼向机身结构传递的载荷特性,为后续舱内噪声预计提供了数据输入;并仿真辨识了发动机振动传递的主路径,为舱内声学设计及发动机隔振安装提供了基础数据.文中研究结果对我国大型客机的减振降噪设计工作有重要的工程参考价值.

  16. The subsurface geology along the route of the new bridge at Ada Ciganlija Island (Belgrade, Serbia

    Directory of Open Access Journals (Sweden)

    Knežević Slobodan

    2012-01-01

    Full Text Available The largest single-pylon, cable-stayed bridge in the world was opened in Belgrade on January 1, 2012 and it passes over the tip of the Ada Ciganlija Island. Its monumentality, architectural design and construction innovations became a new symbol of Belgrade. Core samples from the boreholes drilled for the construction of the bridge revealed a relatively complex subsurface geological structure. An Upper Cretaceous-Paleogene flysch formation and Middle Miocene Sarmatian sediments were found near the surface on the right bank of the Sava River. However, at the tip of Ada Ciganlija, the Upper Cretaceous-Palaeogene flysch strata were found below several different Miocene and Quaternary units. In the deepest borehole DB-6, the flysch deposits were found at a depth of 80 meters. On the left bank of the Sava River in New Belgrade, only Upper Miocene Pannonian marls and Pleistocene and Holocene alluvial deposits were drilled. Based on a comparative analysis of the borehole sections and structural characteristics of the rocks, it could be concluded that the Pre-Quaternary units cascade subsided along sub-parallel faults towards N-NW. [Projekat Ministarstva nauke Republike Srbije, br. 176015

  17. Far-Field Acoustic Power Level and Performance Analyses of F31/A31 Open Rotor Model at Simulated Scaled Takeoff, Nominal Takeoff, and Approach Conditions: Technical Report I

    Science.gov (United States)

    Sree, Dave

    2015-01-01

    Far-field acoustic power level and performance analyses of open rotor model F31/A31 have been performed to determine its noise characteristics at simulated scaled takeoff, nominal takeoff, and approach flight conditions. The nonproprietary parts of the data obtained from experiments in 9- by 15-Foot Low-Speed Wind Tunnel (9?15 LSWT) tests were provided by NASA Glenn Research Center to perform the analyses. The tone and broadband noise components have been separated from raw test data by using a new data analysis tool. Results in terms of sound pressure levels, acoustic power levels, and their variations with rotor speed, angle of attack, thrust, and input shaft power have been presented and discussed. The effect of an upstream pylon on the noise levels of the model has been addressed. Empirical equations relating model's acoustic power level, thrust, and input shaft power have been developed. The far-field acoustic efficiency of the model is also determined for various simulated flight conditions. It is intended that the results presented in this work will serve as a database for comparison and improvement of other open rotor blade designs and also for validating open rotor noise prediction codes.

  18. Vulture rescue and rehabilitation in South Africa: An urban perspective

    Directory of Open Access Journals (Sweden)

    V. Naidoo

    2011-04-01

    Full Text Available SouthAfrica is home to 9 vulture species, of which 7 are endangered. While the cause of the population declines remains largely speculative, a vast amount of effort has been dedicated towards the protection of populations by ensuring sustainable and safe food sources for the various colonies. Limited focus was placed in the past on efforts related to the rescue and/or rehabilitation (R&R of injured birds and the release of these birds back into the wild. This paper provides an overview of the causes, the impact and success of 3 organisations involved in R&R efforts of vultures in the Magaliesberg mountain range and surrounding areas over a period of 10 years. Study material included 162 Cape griffon (CGV and 38 African white-backed (AWBV vultures. Datasets include the number, sex and age of birds received, the reason the vultures were brought in for R&R, surgical interventions performed and outcomes of rescue efforts. The CGV dominated the rehabilitation attempts. Results further show that a large number of apparently healthy birds were presented for veterinary treatment. The R&R data clearly indicate that the major cause of injuries was birds colliding with overhead pylons, as a high number of soft tissue and skeletal injuries were observed. The study also shows that successful releases of rescued birds are possible. It is concluded that urbanisation has had a major negative impact on vultures around the Magaliesberg mountain range.

  19. Comparison of various procedures for progressive collapse analysis of cable-stayed bridges

    Institute of Scientific and Technical Information of China (English)

    Jian-guo CAI; Yi-xiang XU; Li-ping ZHUANG; Jian FENG; Jin ZHANG

    2012-01-01

    Alternate path (AP) method is the most widely used method for the progressive collapse analysis,and its application in frame structures has been well proved.However,the application of AP method for other structures,especially for cable-stayed structures,should be further developed.The four analytical procedures,i.e.,linear static,nonlinear static,linear dynamic,and nonlinear dynamic were firstly improved by taking into account the initial state.Then a cable-stayed structure was studied using the four improved methods.Furthermore,the losses of both one cable and two cables were discussed.The results show that for static and dynamic analyses of the cable-stayed bridges,there is large difference between the results obtained from simulations starting with either a deformed or a nondeformed configuration at the time of cable loss.The static results are conservative in the vicinity of the ruptured cable,but the dynamic effect of the cable loss in the area farther away from the loss-cable cannot be considered.Moreover,the dynamic amplification factor of 2.0 is found to be a good estimate for static analysis procedures,since linear static and linear dynamic procedures yield approximately the same maximum vertical deflection.The results of the comprehensive evaluation of the cable failure show that the tread of the progressive failure of the cable-stayed bridges decreases when the location of the failed cables is closer to the pylon.

  20. The structure of powder snow avalanches

    Science.gov (United States)

    Sovilla, Betty; McElwaine, Jim N.; Louge, Michel Y.

    2015-01-01

    Powder snow avalanches (PSAs) can be hundreds of metres high and descend at astonishing speeds. This review paints a composite picture of PSAs from data acquired at the Vallée de la Sionne test site in Switzerland, including time-histories of snow cover thickness from buried RADAR and, at several elevations on a pylon, impact pressures from load cells, air pressure, particle velocity from optical sensors, and cloud density and particle cluster size from capacitance probes. PSAs feature distinct flow regions with stratification in mean density. At the head, highly fluctuating impact pressures weaken with elevation, while vertical velocity profiles evolve rapidly along the flow, suggesting that surface snow layers of light, cold, cohesionless snow erupt into a turbulent, inhomogeneous, recirculating frontal cloud region. For hundreds of metres behind the head, cloud stratification sharpens with the deposition of suspended cloud particles, while a denser basal flow of increasing thickness forms as deeper, warmer and heavier parts of the weakened snow cover are entrained. Toward the tail, vertical velocity profiles are more uniform, impact pressures become lower and steadier as the flow becomes thinner, and snow pack entrainment is negligible.

  1. Research on the special lifting devices for steel box girders of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Chen Ming; Wu Qihe; Luo Chengbin; Zhou Hanfa

    2009-01-01

    Sutong Bridge is a cable-stayed bridge with a steel box girder and a main span of 1 088 m. The steel box girder of main span includes five portions: back span large unit, large block of pylon, standard girder, back span closure girder and middle span closure girder. Each back span large unit is fabricated by welding several deck segments together in factory, and is erected by floating crane. As navigational clearance of the main bridge is high, the traditional truss lifting device can' t satisfy the requirement of domestic lifting cranes for this kind of lifting height and weight. Hence, a kind of lighter lifting device for the erection of back span large units was accepted for this bridge. In this paper, the design and use of this lifting device is introduced.The upper structure used lifting gantry to install the standard girder segment by cantilever method. Because the bridge's navigation clearance is high, and the girder segment is wide and heavy, the meteorology and hydrology condition of the bridge district is abominable, and the requirements of long cable girder side pull-in, structure and performance propose high request to the lifting gantry. In this paper, the design and use key point of long cable pull-in angle adjustment device integrate into lifting gantry is introduced.

  2. The Use of Airborne and Mobile Laser Scanning for Modeling Railway Environments in 3D

    Directory of Open Access Journals (Sweden)

    Lingli Zhu

    2014-04-01

    Full Text Available This paper presents methods for 3D modeling of railway environments from airborne laser scanning (ALS and mobile laser scanning (MLS. Conventionally, aerial data such as ALS and aerial images were utilized for 3D model reconstruction. However, 3D model reconstruction only from aerial-view datasets can not meet the requirement of advanced visualization (e.g., walk-through visualization. In this paper, objects in a railway environment such as the ground, railroads, buildings, high voltage powerlines, pylons and so on were reconstructed and visualized in real-life experiments in Kokemaki, Finland. Because of the complex terrain and scenes in railway environments, 3D modeling is challenging, especially for high resolution walk-through visualizations. However, MLS has flexible platforms and provides the possibility of acquiring data in a complex environment in high detail by combining with ALS data to produce complete 3D scene modeling. A procedure from point cloud classification to 3D reconstruction and 3D visualization is introduced, and new solutions are proposed for object extraction, 3D reconstruction, model simplification and final model 3D visualization. Image processing technology is used for the classification, 3D randomized Hough transformations (RHT are used for the planar detection, and a quadtree approach is used for the ground model simplification. The results are visually analyzed by a comparison with an orthophoto at a 20 cm ground resolution.

  3. Plant response to utility right of way construction in the Mojave Desert

    Science.gov (United States)

    Lathrop, Earl W.; Archbold, Edwin F.

    1980-05-01

    Disturbance of flora from utility construction tends to generate new plant growth. This growth changes productivity, diversity, and stability. Although the enhancement of vegetation may balance out the biomass destroyed by the original disturbance, it often adversely affects the quality of the vegetation. Percentage composition of the dominant long-lived perennials combined with quantitative measures are used to assess longterm effects of utility corridor construction. Differential effects of enhancement of vegetation are found along road edges, enhancement under wires of powerlines, and over trenches dug for pipelines. Areas under powerline pylons seem to receive the greatest damage and also show the most variable recovery of vegetation. Significant recovery rates are noticeable where the time span between year of construction has allowed for considerable regrowth of the older corridor. Recovery rates depend on soil type, landform, and other physical features of the disturbed sites. Drastic disturbance in one area or transect site may impede vegetation recovery, whereas slight disturbance might enhance vegetation in another, tending to offset the effect of the drastic disturbance. Disturbed areas and control areas may appear to have similar vegetation covers, biomasses, and densities, but these similarities often vanish when one examines qualitative aspects, such as proportion of long-lived species and presence of characteristic dominants.

  4. Research Pilot Milt Thompson in M2-F2 Aircraft Attached to B-52 Mothership

    Science.gov (United States)

    1966-01-01

    NASA research pilot Milt Thompson sits in the M2-F2 'heavyweight' lifting body research vehicle before a 1966 test flight. The M2-F2 and the other lifting-body designs were all attached to a wing pylon on NASA's B-52 mothership and carried aloft. The vehicles were then drop-launched and, at the end of their flights, glided back to wheeled landings on the dry lake or runway at Edwards AFB. The lifting body designs influenced the design of the Space Shuttle and were also reincarnated in the design of the X-38 in the 1990s. NASA B-52, Tail Number 008, is an air launch carrier aircraft, 'mothership,' as well as a research aircraft platform that has been used on a variety of research projects. The aircraft, a 'B' model built in 1952 and first flown on June 11, 1955, is the oldest B-52 in flying status and has been used on some of the most significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft

  5. Structural Behavior of a Long-Span Partially Earth-Anchored Cable-Stayed Bridge during Installation of a Key Segment by Thermal Prestressing

    Directory of Open Access Journals (Sweden)

    Sang-Hyo Kim

    2016-08-01

    Full Text Available This study investigated structural behavior of long-span partially earth-anchored cable-stayed bridges with a main span length of 810 m that use a new key segment closing method based on a thermal prestressing technique. A detailed construction sequence analysis matched with the free cantilever method (FCM was performed using a three-dimensional finite element (FE model of a partially earth-anchored cable-stayed bridge. The new method offers an effective way of connecting key segments by avoiding large movements resulting from the removal of the longitudinal restraint owing to the asymmetry of axial forces in the girders near the pylons. The new method develops new member forces through the process of heating the cantilever system before installing the key segment and cooling the system continuously after installing key segments. The resulting forces developed by the thermal process enhance the structural behavior of partially earth-anchored cable-stayed bridges owing to decreased axial forces in the girders.

  6. High speed turboprop aeroacoustic study (counterrotation). Volume 1: Model development

    Science.gov (United States)

    Whitfield, C. E.; Mani, R.; Gliebe, P. R.

    1990-01-01

    The isolated counterrotating high speed turboprop noise prediction program was compared with model data taken in the GE Aircraft Engines Cell 41 anechoic facility, the Boeing Transonic Wind Tunnel, and in NASA-Lewis' 8x6 and 9x15 wind tunnels. The predictions show good agreement with measured data under both low and high speed simulated flight conditions. The installation effect model developed for single rotation, high speed turboprops was extended to include counterotation. The additional effect of mounting a pylon upstream of the forward rotor was included in the flow field modeling. A nontraditional mechanism concerning the acoustic radiation from a propeller at angle of attach was investigated. Predictions made using this approach show results that are in much closer agreement with measurement over a range of operating conditions than those obtained via traditional fluctuating force methods. The isolated rotors and installation effects models were combines into a single prediction program, results of which were compared with data taken during the flight test of the B727/UDF engine demonstrator aircraft. Satisfactory comparisons between prediction and measured data for the demonstrator airplane, together with the identification of a nontraditional radiation mechanism for propellers at angle of attack are achieved.

  7. Autoimmune thyroid diseases and Helicobacter pylori: The correlation is present only in Graves's disease

    Institute of Scientific and Technical Information of China (English)

    Vincenzo Bassi; Gennaro Marino; Alba Iengo; Olimpia Fattoruso; Crescenzo Santinelli

    2012-01-01

    AIM:To investigate the correlation between autoimmune thyroid diseases (ATDs) and the prevalence of Cag-A positive strains of Helicobacter pylori (H.pylon)in stool samples.METHODS:Authors investigated 112 consecutive Caucasian patients (48 females and 4 males with Graves' disease and 54 females and 6 males with Hashimoto's thyroiditis HT),at their first diagnosis of ATDs.Authors tested for H.pylori in stool samples using an amplified enzyme immunoassay and Cag-A in serum samples using an enzyme-linked immunoassay method (ELISA).The results were analyzed using the two-sided Fisher's exact test and the respective odds ratio (OR) was calculated.RESULTS:A marked correlation was found between the presence of H.pylori (P ≤ 0.0001,OR 6.3) and,in particular,Cag-A positive strains (P ≤ 0.005,OR 5.3)in Graves' disease,but not in Hashimoto's thyroiditis,where authors found only a correlation with Cag-A strains (P ≤ 0.005,OR 8.73) but not when H.pylori was present.CONCLUSION:The marked correlation between H.pylori and Cag-A,found in ATDs,could be dependent on the different expression of adhesion molecules in the gastric mucosa.

  8. Project to construct the 315 kV Chenier-Outaouais line : public inquiry report; Projet de construction d'une ligne a 315 kV, la ligne Chenier-Outaouais : rapport d'enquete et d'audience publique

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-09-15

    This paper discussed the proposed construction of a 315 kV power transmission line from the Chenier substation near Mirabel, Quebec to the Outaouais substation in Ange Gardien, Quebec. The 114 km long line will cross 14 municipalities, mostly across private properties. Three quarters of the line will cross agricultural land and the remainder will be through wooded areas. The proposed project requires 2 circuits and 6 conducting wires supported by metal pylons. Both the Chenier and Outaouais substations will require modifications to transformers, circuit switchgear and regulators. The infrastructure is expected to have a service life of 60 years. Quebec's environmental public hearing board, the Bureau d'audiences publiques sur l'environnement (BAPE) examined the sustainability of the project with respect to environmental aspects, economic development, and public safety. The BAPE held public hearings in Montebello, Quebec to hear citizen's views regarding the project. Participants expressed concerns regarding noise, impact on wildlife, aesthetics and the health hazards of electromagnetic fields. It was concluded that the proposed line is necessary. The power failure following the ice storm in 1998 indicated that the region needs a more stable and reliable supply of electricity. This proposed project is within the objectives of Quebec's new energy strategy and will allow a higher volume of electricity exchange between Quebec and Ontario. refs., tabs., figs.

  9. Radon measurements with a PIN photodiode

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Martin, A. [Laboratorio de Investigacion en Baja Radiactividad (LIBRA), Edificio I-D, Campus Miguel Delibes, Universidad de Valladolid, Valladolid 47011 (Spain) and Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain)]. E-mail: alonsomm@libra.uva.es; Gutierrez-Villanueva, J.L. [Laboratorio de Investigacion en Baja Radiactividad (LIBRA), Edificio I-D, Campus Miguel Delibes, Universidad de Valladolid, Valladolid 47011 (Spain); Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain); Munoz, J.M. [Departamento de Electricidad y Electronica, Universidad de Valladolid, Valladolid 47011 (Spain); Garcia-Talavera, M. [Laboratorio de Investigacion en Baja Radiactividad (LIBRA), Edificio I-D, Campus Miguel Delibes, Universidad de Valladolid, Valladolid 47011 (Spain); Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain); Adamiec, G. [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain); Iniguez, M.P. [Departamento de Fisica Teorica, Atomica y Optica, Universidad de Valladolid, Valladolid 47011 (Spain)

    2006-10-15

    Silicon photodiodes are well suited to detect alphas coming from different sources as neutron reactions or radon daughters. In this work a radon in air detecting device, using an 18x18 mm silicon PIN photodiode is studied. The ionized airborne decay products formed during radon diffusion were focused by an accelerating high voltage to the PIN surface. Several conducting rings were disposed inside a cylindrical PVC vessel in such a way that they reproduced the electric field created by a punctual charge located behind PIN position. Alpha spectra coming from the neutral and ionized species deposited on the PIN surface, dominated by {sup 218}Po and {sup 214}Po progeny peaks, were recorded for varying conditions. Those include radon concentration from a Pylon source, high voltage (thousands of volts) and PIN inverse bias voltage. Different parameters such as temperature and humidity were also registered during data acquisition. The increase in the particle collection efficiency with respect to zero electric field was compared with the corresponding to a parallel plates configuration. A discussion is made in terms of the most appropriate voltages for different radon concentrations.

  10. Distal tibial fracture treated by minimally invasive plate osteosynthesis after external fixation Retrospective clinical and radiographic assessment

    Directory of Open Access Journals (Sweden)

    Al. Șerban

    2014-02-01

    Full Text Available Fractures of the horizontal surface of the distal tibia are known commonly as pylon or plafond fractures, and represent 1-5% of lower extremity fractures, 7-10% of all tibial fractures. The protocol consisted of immediate (within eight to 24 hours open reduction and internal fixation of the fibula, using a fibular plate or one third tubular plate and application of an external fixator spanning the ankle joint. In the second stage, the treatment of proximal and distal tibial fractures with close reduction and MIPPO technique can preserve soft tissue, simplify operative procedure and decrease wound, obtain rigid internal fixation and guarantee early function exercises of ankle joint. In this study we evaluated 22 patients treated in Clinical Emergency Hospital Constanta between April 2012 - July 2013 diagnosed with multifragmentary fractures of the distal tibia. This study evaluates the treatment of complex fractures of distal tibia with locked plate after external fixation. There were 17 males and 5 females of mean age 51,7 years (31-68. The mean follow-up period was 14 weeks. (Ranging from 9-16 weeks. All patients were fully weight bearing at 16 weeks (ranging 9-16 weeks showing radiological union. There were no cases of failures of fixation, or rotational misalignment. No significant complication was observed in our patients. MIPO is an effective method of treatment for distal tibial fractures, reduce surgical trauma and maintain a more biologically favorable environment for fracture healing, reducing risks of infection and nonunion.

  11. Mausoleum of the XIV century in the southern part of the Bolgar settlement (excavation trench CLXXIV. Research 2012

    Directory of Open Access Journals (Sweden)

    Elkina Irina I.

    2014-06-01

    Full Text Available The results of archaeological studies on the remains of a stone mausoleum, discovered in the southern part of the Bulgar fortified settlement site in 2012 are published. The preserved remains of the building include only a 2.7-meter-long section of the eastern wall foundation, the northeast corner, and pylon bases. Despite a considerably ruined condition of the building, it was possible to fix its form, width and depth of the unpreserved foundations on the basis of the massifs consisting of tightly rammed crumbs and small-size white stones. Under the foundations of the mausoleum, a ditch of yet unclear purpose, round in plane, about 10 m in diameter, was uncovered. The construction can be dated to the late 14th century. The layout of the building is in general lines similar to other known mausoleums of the Bulgar fortified settlement site. Inside the mausoleum, a burial of at least 9 individuals in wooden coffins was found, and around the building the presence of a large cemetery was discovered.

  12. The commercial development of water repellent coatings for high voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, S. R. [ORNL; Daniel, A. [Southwire Company

    2013-10-31

    The purpose of the Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and Southwire Company was to jointly develop a low cost, commercially viable, water-repellant anti-icing coating system for high voltage transmission lines. Icing of power lines and other structures caused by freezing rain events occurs annually in the United States, and leads to severe and prolonged power outages. These outages cause untold economic and personal distress for many American families and businesses. Researchers at the Department of Energy?s Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee have previously developed a set of superhydrophobic coatings with remarkable anti-icing properties that could potentially be sprayed or painted onto high-tension power lines and pylons. These coatings drastically reduce ice accumulation on these structures during freezing rain events. The project involved obtaining technical input, supplies and test high voltage cables from Southwire, along with the joint development of anti-icing coating techniques, which would result in a commercial license agreement between Southwire and ORNL, and potentially other companies requiring water repellent anti-icing coatings.

  13. The commercial development of water repellent coatings for high voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Scott Robert [ORNL

    2013-10-01

    The purpose of the Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and Southwire Company was to jointly develop a low cost, commercially viable, water-repellant anti-icing coating system for high voltage transmission lines. Icing of power lines and other structures caused by freezing rain events occurs annually in the United States, and leads to severe and prolonged power outages. These outages cause untold economic and personal distress for many American families and businesses. Researchers at the Department of Energy s Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee have previously developed a set of superhydrophobic coatings with remarkable anti-icing properties that could potentially be sprayed or painted onto high-tension power lines and pylons. These coatings drastically reduce ice accumulation on these structures during freezing rain events. The project involved obtaining technical input, supplies and test high voltage cables from Southwire, along with the joint development of anti-icing coating techniques, which would result in a commercial license agreement between Southwire and ORNL, and potentially other companies requiring water repellent anti-icing coatings.

  14. A dynamic multiblock approach to solving the unsteady Euler equations about complex configurations

    Science.gov (United States)

    Arabshahi, Abdollah

    The objective is the development of a numerical method which can accurately and economically solve the unsteady Euler equations for three-dimensional flow fields around complex configurations, particularly a generic aircraft with a store in the captive and vertical launch position. A cell centered finite volume spatial discretization is applied to the three-dimensional, time-dependent, Euler equations written in general time-dependent curvilinear coordinates. Two algorithms are presented for solving the system of Euler equations. The first algorithm is based on flux-vector splitting while the second algorithm is based on flux-difference splitting using Roe averaged variables. For both algorithms, an implicit upwind biased approach is employed to integrate the spatially discretized equations in time. The multiblock technique utilizes the concept of decomposing the flow field between the surfaces of the configuration and some outer far field boundary into a set of blocks. Calculated results compared with experimental data indicate that the present Euler solver can calculate transonic flow fields efficiently and accurately over complex geometries. Furthermore, the results demonstrate how computational fluid dynamics (CFD) can be used to accurately simulate steady and, for the first time, unsteady fluid flow over a complete wing-pylon-store configuration with the store in the captive and vertical launch positions.

  15. Simulation and optimization of steering(handling)stability of Formula SAE racing vehicle%大学生方程式赛车操纵稳定性仿真与优化

    Institute of Scientific and Technical Information of China (English)

    查云飞; 胡亚辉; 王浩; 王大千; 钟勇

    2015-01-01

    基于 Adams/Car 建立大学生方程式赛车的整车虚拟样机模型,参照国标 GB/T 6323-2014进行了虚拟样机稳态回转和蛇形仿真试验,测试赛车的操纵稳定性,并根据 QC /T 480-1999对仿真结果进行评价。利用 Adams/Insight 模块对虚拟样机模型参数进一步优化,优化后的参数对整车的操作稳定性具有明显的改善作用,为赛车设计提供了参考。%A virtual prototype model of a Formula Society of Automative Engineers(SAE)racing ve-hicle was established based on Adams/Car.Simulation of the virtual model steady static circling and pylon course slalom test were conducted in accordance with the Chinese national standard GB /T 6323 -2014 to test the steering (handling)stability of the vehicle.The results of the simulation were evaluated in accordance with QC /T 480 -1999.The parameters of the virtual prototype model were optimized using Adams/Insight module,which improved the steering (handling)stability of the vehicle.

  16. Prosthetic interventions for people with transtibial amputation: Systematic review and metaanalysis of high-quality prospective literature and systematic reviews

    Directory of Open Access Journals (Sweden)

    M. Jason Highsmith, PhD, DPT, CP, FAAOP

    2016-03-01

    Full Text Available Considering transtibial amputation (TTA rehabilitation costs and complexity, high-quality literature should inform clinical practice. Systematic reviews (SRs suggest this is not the case. This article's purpose was to review the highest-quality evidence available to guide clinical practice for TTA regarding five prosthetic intervention areas. Six databases were searched for high-quality SRs and prospective clinical trials (randomized clinical trials [RCTs]. Reviewers screened, sorted, rated (i.e., methodologic quality, bias risk, and extracted article data. Meta-analyses were conducted when possible. Thirty-one references were included (25 RCTs and 6 SRs. Five topical areas emerged (alignment, feet and ankles, interface, postoperative care, pylons. Twenty-three evidence statements were supported by level 2 evidence and eight by level 1 evidence. All RCTs reported randomization and reasonable data presentation. Concealed allocation and blinding were not widely used. Mean attrition was 11%. SRs included no meta-analyses. Functional level was poorly reported. Grouping feet and ankle components by functional classification enabled meta-analyses, though variance was considerable given the small sample sizes. Prosthetic interventions are generally safe for TTAs. High-quality literature enabled formulation of evidence statements to support select clinical practice areas, though quantity was lacking. Thus, numerous topics related to TTA care lack rigorous evidence. Although blinding in prosthetic research requires increased funding and effort, it could greatly improve the methodologic quality of prosthetic research.

  17. Interrater reliability of mechanical tests for functional classification of transtibial prosthesis components distal to the socket

    Directory of Open Access Journals (Sweden)

    Matthew J. Major, PhD

    2015-08-01

    Full Text Available Substantial evidence suggests that the design and associated mechanical function of lower-limb prostheses affects user health and mobility, supporting common standards of clinical practice for appropriate matching of prosthesis design and user needs. This matching process is dependent on accurate and reliable methods for the functional classification of prosthetic components. The American Orthotic & Prosthetic Association developed a set of tests for L-code characterization of prosthesis mechanical properties to facilitate functional classification of passive below-knee prosthetic components. The mechanical tests require use of test-specific fixtures to be installed in a materials testing machine by a test administrator. Therefore, the purpose of this study was to assess the interrater reliability of test outcomes between two administrators using the same testing facility. Ten prosthetic components (8 feet and 2 pylons that spanned the range of commercial designs were subjected to all appropriate tests. Tests with scalar outcomes demonstrated high interrater reliability (intraclass correlation coefficient (2,1 >/= 0.935, and there was no discrepancy in observation-based outcomes between administrators, suggesting that between-administrator variability may not present a significant source of error. These results support the integration of these mechanical tests for prosthesis classification, which will help enhance objectivity and optimization of the prosthesis-patient matching process for maximizing rehabilitation outcomes.

  18. Interrater reliability of mechanical tests for functional classification of transtibial prosthesis components distal to the socket.

    Science.gov (United States)

    Major, Matthew J; Johnson, William Brett; Gard, Steven A

    2015-01-01

    Substantial evidence suggests that the design and associated mechanical function of lower-limb prostheses affects user health and mobility, supporting common standards of clinical practice for appropriate matching of prosthesis design and user needs. This matching process is dependent on accurate and reliable methods for the functional classification of prosthetic components. The American Orthotic & Prosthetic Association developed a set of tests for L-code characterization of prosthesis mechanical properties to facilitate functional classification of passive below-knee prosthetic components. The mechanical tests require use of test-specific fixtures to be installed in a materials testing machine by a test administrator. Therefore, the purpose of this study was to assess the interrater reliability of test outcomes between two administrators using the same testing facility. Ten prosthetic components (8 feet and 2 pylons) that spanned the range of commercial designs were subjected to all appropriate tests. Tests with scalar outcomes demonstrated high interrater reliability (intraclass correlation coefficient(2,1) >/= 0.935), and there was no discrepancy in observation-based outcomes between administrators, suggesting that between-administrator variability may not present a significant source of error. These results support the integration of these mechanical tests for prosthesis classification, which will help enhance objectivity and optimization of the prosthesis-patient matching process for maximizing rehabilitation outcomes.

  19. Aging Theories for Establishing Safe Life Spans of Airborne Critical Structural Components

    Science.gov (United States)

    Ko, William L.

    2003-01-01

    New aging theories have been developed to establish the safe life span of airborne critical structural components such as B-52B aircraft pylon hooks for carrying air-launch drop-test vehicles. The new aging theories use the equivalent-constant-amplitude loading spectrum to represent the actual random loading spectrum with the same damaging effect. The crack growth due to random loading cycling of the first flight is calculated using the half-cycle theory, and then extrapolated to all the crack growths of the subsequent flights. The predictions of the new aging theories (finite difference aging theory and closed-form aging theory) are compared with the classical flight-test life theory and the previously developed Ko first- and Ko second-order aging theories. The new aging theories predict the number of safe flights as considerably lower than that predicted by the classical aging theory, and slightly lower than those predicted by the Ko first- and Ko second-order aging theories due to the inclusion of all the higher order terms.

  20. Classifying prosthetic use via accelerometry in persons with transtibial amputations

    Directory of Open Access Journals (Sweden)

    Morgan T. Redfield, MSEE

    2013-12-01

    Full Text Available Knowledge of how persons with amputation use their prostheses and how this use changes over time may facilitate effective rehabilitation practices and enhance understanding of prosthesis functionality. Perpetual monitoring and classification of prosthesis use may also increase the health and quality of life for prosthetic users. Existing monitoring and classification systems are often limited in that they require the subject to manipulate the sensor (e.g., attach, remove, or reset a sensor, record data over relatively short time periods, and/or classify a limited number of activities and body postures of interest. In this study, a commercially available three-axis accelerometer (ActiLife ActiGraph GT3X+ was used to characterize the activities and body postures of individuals with transtibial amputation. Accelerometers were mounted on prosthetic pylons of 10 persons with transtibial amputation as they performed a preset routine of actions. Accelerometer data was postprocessed using a binary decision tree to identify when the prosthesis was being worn and to classify periods of use as movement (i.e., leg motion such as walking or stair climbing, standing (i.e., standing upright with limited leg motion, or sitting (i.e., seated with limited leg motion. Classifications were compared to visual observation by study researchers. The classifier achieved a mean +/– standard deviation accuracy of 96.6% +/– 3.0%.

  1. Classifying prosthetic use via accelerometry in persons with transtibial amputations.

    Science.gov (United States)

    Redfield, Morgan T; Cagle, John C; Hafner, Brian J; Sanders, Joan E

    2013-01-01

    Knowledge of how persons with amputation use their prostheses and how this use changes over time may facilitate effective rehabilitation practices and enhance understanding of prosthesis functionality. Perpetual monitoring and classification of prosthesis use may also increase the health and quality of life for prosthetic users. Existing monitoring and classification systems are often limited in that they require the subject to manipulate the sensor (e.g., attach, remove, or reset a sensor), record data over relatively short time periods, and/or classify a limited number of activities and body postures of interest. In this study, a commercially available three-axis accelerometer (ActiLife ActiGraph GT3X+) was used to characterize the activities and body postures of individuals with transtibial amputation. Accelerometers were mounted on prosthetic pylons of 10 persons with transtibial amputation as they performed a preset routine of actions. Accelerometer data was postprocessed using a binary decision tree to identify when the prosthesis was being worn and to classify periods of use as movement (i.e., leg motion such as walking or stair climbing), standing (i.e., standing upright with limited leg motion), or sitting (i.e., seated with limited leg motion). Classifications were compared to visual observation by study researchers. The classifier achieved a mean +/- standard deviation accuracy of 96.6% +/- 3.0%.

  2. A joint numerical and experimental study of the jet of an aircraft engine installation with advanced techniques

    Science.gov (United States)

    Brunet, V.; Molton, P.; Bézard, H.; Deck, S.; Jacquin, L.

    2012-01-01

    This paper describes the results obtained during the European Union JEDI (JEt Development Investigations) project carried out in cooperation between ONERA and Airbus. The aim of these studies was first to acquire a complete database of a modern-type engine jet installation set under a wall-to-wall swept wing in various transonic flow conditions. Interactions between the engine jet, the pylon, and the wing were studied thanks to ¤advanced¥ measurement techniques. In parallel, accurate Reynolds-averaged Navier Stokes (RANS) simulations were carried out from simple ones with the Spalart Allmaras model to more complex ones like the DRSM-SSG (Differential Reynolds Stress Modef of Speziale Sarkar Gatski) turbulence model. In the end, Zonal-Detached Eddy Simulations (Z-DES) were also performed to compare different simulation techniques. All numerical results are accurately validated thanks to the experimental database acquired in parallel. This complete and complex study of modern civil aircraft engine installation allowed many upgrades in understanding and simulation methods to be obtained. Furthermore, a setup for engine jet installation studies has been validated for possible future works in the S3Ch transonic research wind-tunnel. The main conclusions are summed up in this paper.

  3. Geoarchaeology of Ancient Karnak's harbour (Upper Egypt) : preliminary results derived from sedimentological analyses

    Science.gov (United States)

    Ghilardi, M.

    2009-04-01

    This paper aims to detail the first results of a geomorphological study, led in the western part of the Karnak Temple, Upper Egypt. The geoarchaeological approach privileged here helps to better understand the Nile River dynamics in the neighbourhood of the ancient harbour and of the jetty identified by archaeologists. Based on the study of six stratigraphical profiles, realized by the Egyptian Supreme Council of Antiquities and sixteen manual auger boreholes (up to a maximum depth of 3.50m) drilled in November 2008, the results clearly indicate the continuous presence of Nile River westward of the first Pylon. The boreholes were drilled westward and eastward of the ancient fluvial harbour. Fluvial dynamics characterized by flood events, sandy accretions and large Nile silts depositions are presented and discussed here for later palaeoenvironmental reconstruction. The accurate levelling of the different profiles and boreholes, with the help a topographic survey, allow us to get long sedimentological sequences and to correlate the different sedimentary units. Perspectives of research are introduced with the possibility to realize sedimentological analyses which include the grain-size distribution (sieving method employed) and a magnetic susceptibility study of the different sediments described. Finally, in order to obtain chronostratigraphic sequences, it is also proposed to perform radiocarbon dating on charcoal samples.

  4. Helicobacter pylori infection: an overview in 2013, focus on therapy

    Institute of Scientific and Technical Information of China (English)

    Cui Rongli; Zhou Liya

    2014-01-01

    Objective This article aimed to review the incidence of Helicobacterpylori (H.pylon) infection and its therapy.Data sources Relevant articles published in English were identified by searching in PubMed from 2000 to 2013,with keywords "H.pylori".Important references from selected articles were also retrieved from Elsevier,Wiley,EBSCO,and SPRINGER.The Chinese articles published were searched from China National Knowledge Infrastructure (CNKI).Study selection Articles about "prevalence","gastric carcinoma","peptic ulcer","gastroesophageal reflux disease","functional dyspepsia","pathogenic mechanism","therapy","eradication rate","antibiotic resistance",and "gene polymorphisms" were selected.Results The decreased infection rates of H.pylori could also be linked to the changed disease spectrum,such as the decreased morbidity and recurrence rate of H.pylori-related peptic ulcer,and the increased morbidity of gastroesophageal reflux.Although different treatment regimens have been used for H.pylori infection,the H.pylori eradication rate declined gradually.Due to primary resistance to antibiotics,the gene polymorphism of host and infected strain,and the therapy regimes,H.pylori eradication became even more difficult.Conclusions The prevalence of H.py/ori infection had been decreasing,but the rate of eradication failure has dramatically risen in many countries due to resistance to antibiotic.H.pylori therapy in clinical practice is becoming proqressively more difficult.

  5. A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

    Directory of Open Access Journals (Sweden)

    Paolo Lonetti

    2016-10-01

    Full Text Available A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes

  6. Geometric Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges

    Directory of Open Access Journals (Sweden)

    Wang Hui-Li

    2013-01-01

    Full Text Available Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

  7. Puente sobre el Rin Dusseldorf, Alemania Federal

    Directory of Open Access Journals (Sweden)

    Modemann, H. J.

    1980-05-01

    Full Text Available The bridge over the Rhine, in Dusseldorf- Flehe — one of whose most important jobs is to alleviate traffic from the other bridges in the town of Dusseldorf — consists of three clearly diferentiated parts: — a metal part 368 m. in length; — another in prestressed concrete, 780 m. long, and — an A-shape pylon, acting as element joining both. This bridge has the span clearance record in West Germany, and its metal part constitutes the longest corbel in the world.

    El puente sobre el Rin, en Düsseldorf- Flehe —una de cuyas funciones más Importantes es la de aliviar el tráfico a los demás puentes existentes en la ciudad de Dusseldorf—, consta de tres partes claramente diferenciadas: — una metálica de 368 m de longitud; — otra de hormigón pretensado de 780 m de largo, y — un pilono, en forma de A, que sirve como elemento de unión entre ambas. Este puente ostenta el récord de luz libre en la República Federal Alemana, y su parte metálica constituye el voladizo de mayor longitud del mundo.

  8. Aerodynamic problems of cable-stayed bridges spanning over one thousand meters

    Institute of Scientific and Technical Information of China (English)

    Chen Airong; Ma Rujin; Wang Dalei

    2009-01-01

    Tbe elongating of cable-stayed bridge brings a series of aerodynamic problems. First of all, geometric nonlin-ear effect of extreme long cable is much more significant for cable-stayed bridge spanning over one thousand meters. Lat-eral static wind load will generate additional displacement of long cables, which causes the decrease of supporting rigidi-ty of the whole bridge and the change of dynamic properties. Wind load, being the controlling load in the design of ca-hie-stayed bridge, is a critical problem and needs to be solved. Meanwhile, research on suitable system between pylon and deck indicates fixed-fixed connection system is an effective way for improvement performance of cable-stayed bridges under longitudinal wind load. In order to obtain aerodynamic parameters of cable-stayed bridge spanning over one thou-sand meters, identification method for flutter derivatives of full bridge aero-elastic model is developed in this paper. Furthermore, vortex induced vibration and Reynolds number effect are detailed discussed.

  9. Ambient vibration monitoring of slender structures by microwave interferometer remote sensing

    Science.gov (United States)

    Gikas, Vassilis

    2012-11-01

    This paper examines the potential of microwave radar interferometry for monitoring the dynamic behaviour of large civil engineering works. It provides an overview of the method, its principles of operation with particular emphasis given on the IBIS-S system. Two areas of application are considered and the results of the analyses are presented and discussed. The first experimental study involves the monitoring of the dynamic response of a tall power plant chimney due to wind load. The second example examines the dynamic behaviour of a long cable-stayed bridge. In this case, the focus is placed on the effects that individual traffic events impose on the vibration response of the main span of the bridge deck and the bridge pylons. Analysis of the results provides detailed displacement time-histories and the dominant frequencies observed at the top of the chimney and along the bridge deck and the top of the towers. Also, cross-comparisons and discussions with the results obtained at the same structures using different sensor configurations are provided.

  10. Retinol-binding protein, acute phase reactants and Helicobacter pylori infection in patients with gastric adenocarcinoma

    Institute of Scientific and Technical Information of China (English)

    Nicolas Tsavaris; Christos Koufos; Athanasios Archimandritis; Christos Kosmas; Petros Kopterides; Dimitrios Tsikalakis; Hlias Skopelitis; Fotini Sakelaridi; Nikitas Papadoniou; Michalis Tzivras; Vasilios Balatsos

    2005-01-01

    AIM: To determine the serum levels of c-reactive protein (CRP), transferrin (TRF), a2-macroglobulin (A2M),ceruloplasmin (CER), a1-acid glycoprotein (AAG), prealbumin (P-ALB) and retinol-binding protein (RBP) in gastric carcinoma patients and to explore their possible correlation with underlying Helicobacter pylori (H pylon)infection.METHODS: We measured the serum levels of CRP, TRF,A2M, CER, AAG, P-ALB, and RBP in 153 preoperative patients (93 males; mean age: 63.1±11.3 years) with non-cardia gastric adenocarcinoma and 19 healthy subjects.RESULTS: The levels of CRP, CER, RBP, andAAG in cancer patients were significantly higher than those in healthy controls (P<0.0001), while no difference was found regarding the TRF, P-ALB, and A2M levels. Cancer patients with H pylori infection had significantly lower RBP values compared to non-infected ones (P<0.0001)and also higher values of CRP and AAG (P = 0.09 and P = 0.08, respectively).CONCLUSION: High serum levels of CRP, CER and AAG in cancer patients do not seem to be related to H pylori infection. Retinol-binding protein seems to discriminate between infected and non-infected patients with gastric carcinoma. Further studies are needed to explore if it is directly involved in the pathogenesis of the disease or is merely an epiphenomenon.

  11. Drag prediction method of powered-on civil aircraft based on thrust drag bookkeeping

    Directory of Open Access Journals (Sweden)

    Zhang Yufei

    2015-08-01

    Full Text Available A drag prediction method based on thrust drag bookkeeping (TDB is introduced for civil jet propulsion/airframe integration performance analysis. The method is derived from the control volume theory of a powered-on nacelle. Key problem of the TDB is identified to be accurate prediction of velocity coefficient of the powered-on nacelle. Accuracy of CFD solver is validated by test cases of the first AIAA Propulsion Aerodynamics Workshop. Then the TDB method is applied to thrust and drag decomposing of a realistic aircraft. A linear relation between the computations assumed free stream Mach number and the velocity coefficient result is revealed. The thrust losses caused by nozzle internal drag and pylon scrubbing are obtained by the isolated nacelle and mapped on to the in-flight whole configuration analysis. Effects of the powered-on condition are investigated by comparing through-flow configuration with powered-on configuration. The variance on aerodynamic coefficients and pressure distribution is numerically studied.

  12. RANDOM FORESTS BASED MULTIPLE CLASSIFIER SYSTEM FOR POWER-LINE SCENE CLASSIFICATION

    Directory of Open Access Journals (Sweden)

    H. B. Kim

    2012-09-01

    Full Text Available The increasing use of electrical energy has yielded more necessities of electric utilities including transmission lines and electric pylons which require a real-time risk monitoring to prevent massive economical damages. Recently, Airborne Laser Scanning (ALS has become one of primary data acquisition tool for corridor mapping due to its ability of direct 3D measurements. In particular, for power-line risk management, a rapid and accurate classification of power-line objects is an extremely important task. We propose a 3D classification method combining results obtained from multiple classifier trained with different features. As a base classifier, we employ Random Forests (RF which is a composite descriptors consisting of a number of decision trees populated through learning with bootstrapping samples. Two different sets of features are investigated that are extracted in a point domain and a feature (i.e., line & polygon domain. RANSAC and Minimum Description Length (MDL are applied to create lines and a polygon in each volumetric pixel (voxel for the line & polygon features. Two RFs are trained from the two groups of features uncorrelated by Principle Component Analysis (PCA, which results are combined for final classification. The experiment with two real datasets demonstrates that the proposed classification method shows 10% improvements in classification accuracy compared to a single classifier.

  13. Compensatory mechanism involving the knee joint of the intact limb during gait in unilateral below-knee amputees.

    Science.gov (United States)

    Beyaert, C; Grumillier, C; Martinet, N; Paysant, J; André, J-M

    2008-08-01

    This study evaluated the asymmetry of knee kinetics during uncomfortable gait induced by prosthesis misalignment to further demonstrate the compensatory function of the knee joint of the intact limb during gait. Three-dimensional gait analysis including knee kinematics and kinetics at the beginning of stance phase was conducted in 15 healthy subjects and 17 unilateral trans-tibial amputees (TTA) walking at self-selected speed in three conditions of prosthetic alignment: initial alignment (IA); initial alignment altered either by 6 degrees of internal rotation (IR) or by 6 degrees of external rotation (ER) applied on the pylon. Patients reported best comfort of gait in IA condition and discomfort mainly in IR condition. Maximum knee flexion and knee total work at power phases K0-K2 were significantly higher in intact limbs compared to prosthetic and control limbs. In intact limbs, these variables had significantly higher values (+10-35%, pknee kinetics of the prosthetic limb, which suggests a protective mechanism. Knee kinetics of the intact limb did alter, which suggests a compensatory mechanism.

  14. Application study on the first cable-stayed bridge with CFRP cables in China

    Directory of Open Access Journals (Sweden)

    Kuihua Mei

    2015-08-01

    Full Text Available In order to push forward the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main components of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During constructing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge could meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values accord well with the calculated values. Further, creep deformation of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

  15. Static load bearing exercises of individuals with transfemoral amputation fitted with an osseointegrated implant: reliability of kinetic data.

    Science.gov (United States)

    Vertriest, Sofie; Coorevits, Pascal; Hagberg, Kerstin; Brånemark, Rickard; Häggström, Eva; Vanderstraeten, Guy; Frossard, Laurent

    2015-05-01

    This study aimed at presenting the intra-tester reliability of the static load bearing exercises (LBEs) performed by individuals with transfemoral amputation (TFA) fitted with an osseointegrated implant to stimulate the bone remodeling process. There is a need for a better understanding of the implementation of these exercises particularly the reliability. The intra-tester reliability is discussed with a particular emphasis on inter-load prescribed, inter-axis and inter-component reliabilities as well as the effect of body weight normalization. Eleven unilateral TFAs fitted with an OPRA implant performed five trials in four loading conditions. The forces and moments on the three axes of the implant were measured directly with an instrumented pylon including a six-channel transducer. Reliability of loading variables was assessed using intraclass correlation coefficients (ICCs) and percentage standard error of measurement values ( %SEMs ). The ICCs of all variables were above 0.9 and the %SEM values ranged between 0 and 87%. This study showed a high between-participants' variance highlighting the lack of loading consistency typical of symptomatic population as well as a high reliability between the loading sessions indicating a plausible correct repetition of the LBE by the participants. However, these outcomes must be understood within the framework of the proposed experimental protocol.

  16. Calibration factor determination for solid nuclear track detectors CR-39 type exposed to Rn-222; Determinacao do fator de calibracao para detectores solidos de tracos nucleares tipo CR-39 expostos a Rn-222

    Energy Technology Data Exchange (ETDEWEB)

    Cazula, Camila Dias; Campos, Marcia Pires de; Mazzilli, Barbara Paci, E-mail: cdcazula@ipen.br, E-mail: mpcampos@ipen.br, E-mail: mazzilli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2014-07-01

    In the detection method with solid nuclear track detector, when a heavy particle rests on the detector surface, causes a breakdown in their molecular structure forming a trace. One of the typical applications of these detectors is the measurement of the concentration of Rn -222 in air, a noble radioactive gas, part of the U-238 series, emitting alpha particles and important in epidemiological studies to protect individuals from natural radiation. To determine the concentration of Rn -222 in the air in a room is necessary to know the density of lines (traces / cm{sup 2}) on the detector surface, the exposure time and the calibration factor. The determination of the calibration factor for CR-39 detectors was taken from the exposure of these to a known concentration of Rn-222. Therefore, the detectors were placed inside a cell of Lucas adapted and subsequently exposed to a concentration of Rn-222 15 kBq / m{sup 3}, by means of the apparatus RN-150 Pylon Electronics Incorporation, which has a source of Ra-226 and releases known concentrations of Rn-222. Six calibration factor determinations were performed, the average value obtained was 0.0534 ±0.0021 (traces / cm{sup 2} per Bq / m{sup 3} day). The results are consistent with literature values for the same type of detector and showed good reproducibility.

  17. Turboelectric Distributed Propulsion Engine Cycle Analysis for Hybrid-Wing-Body Aircraft

    Science.gov (United States)

    Felder, James L.; Kim, Hyun Dae; Brown, Gerald V.

    2009-01-01

    possibilities. The Boeing N2 hybrid-wing-body (HWB) is used as a baseline aircraft for this study. The two pylon mounted conventional turbofans are replaced by two wing-tip mounted turboshaft engines, each driving a superconducting generator. Both generators feed a common electrical bus which distributes power to an array of superconducting motor-driven fans in a continuous nacelle centered along the trailing edge of the upper surface of the wing-body. A key finding was that traditional inlet performance methodology has to be modified when most of the air entering the inlet is boundary layer air. A very thorough and detailed propulsion/airframe integration (PAI) analysis is required at the very beginning of the design process since embedded engine inlet performance must be based on conditions at the inlet lip rather than freestream conditions. Examination of a range of fan pressure ratios yielded a minimum Thrust-specific-fuel-consumption (TSFC) at the aerodynamic design point of the vehicle (31,000 ft /Mach 0.8) between 1.3 and 1.35 FPR. We deduced that this was due to the higher pressure losses prior to the fan inlet as well as higher losses in the 2-D inlets and nozzles. This FPR is likely to be higher than the FPR that yields a minimum TSFC in a pylon mounted engine. 1

  18. Análise do impacto mecânico nas próteses de um sujeito bi-amputado durante a marcha Mechanic impact analysis in the prostheses of a bilateral lower-limb amputee during the gait

    Directory of Open Access Journals (Sweden)

    Thessaly Puel de Oliveira

    2011-03-01

    Full Text Available Observa-se o aumento do uso da acelerometria (medida de impactos na aplicação clínica, especialmente para estudos da marcha acoplando-se os acelerômetros na tíbia. Entretanto, não se tem observado estudos sobre os efeitos dessas vibrações no sistema locomotor de usuários de prótese do membro inferior. O objetivo deste estudo foi medir a quantidade de impacto durante a marcha de um sujeito amputado bilateral transtibial. As coletas foram realizadas durante a marcha do sujeito caminhando a 4 km/h em uma distância de 8 metros com dois acelerômetros piezoelétricos uniaxiais fixados em dois locais distintos da prótese: inicialmente nos encaixes das próteses e posteriormente fixou-se nas hastes metálicas. Utilizou-se estatística descritiva exploratória com Anova One-Way e Post Hoc de Tukey. Constatou-se diferenças significativas com o teste Anova One-Way entre as 10 aquisições em cada local de fixação do acelerômetro. Através do Post Hoc de Tukey observou-se maiores picos de aceleração no encaixe esquerdo (p LATELY We can experience the increasing use of accelerometers (Shock measurements in clinical applications, especially in gait studies attaching the accelerometers in the subjects tibia to impact appraisal. However, there are few studies about the effect of those vibrations in the locomotor system of lower limb prosthetic users. The objective of this study was to measure the amount of vibration during the gait in two different spots in both prostheses of bilateral below-knee amputee. For the acquisition we use a gait speed of 4km/h through 8 meters walk with two uniaxial piezoelectric accelerometers set at two different sites of the prostheses. First, the accelerometers were fixed in both prostheses sockets and later they were fixed in the prostheses pylons. We used descriptive statistics exploratory Anova one-way and post hoc Tukey. The One-way Anova test showed significant differences comparing the accelerometer

  19. Influencing factors of strut-based RBCC performance in ramjet mode①%支板火箭RBCC亚燃模态性能的影响因素

    Institute of Scientific and Technical Information of China (English)

    王亚军; 李江; 何国强; 秦飞

    2016-01-01

    Aiming at two expansion configurations of RBCC combustor, three-dimensional numerical simulation and ground tests were carried out to study the effects of structural parameters and flame stabilization devices on engine performance in ramjet mode. The results show that better combustion reaction and less total pressure loss can be achieved with a smaller expansion angle of the second combustor. Pylons for injection with cavities flame holder in each combustor can effectively enhance combustion of fuel and extend the range of flame propagation. The better performance of thrust increased by 682 N through configuration improvement has been verified with direct-connect test. Moreover, the sustained combustion of fuel after shutting down the rocket could be a-chieved when the cavities location is close to the pylons, in such a case the specific impulse has a nearly 50% increase with rocket off. Pre-combustion shock train can be more easily established in isolator by reducing the width of central strut at Ma=4 and better reaction of subsonic combustion can be ensured, in this case the engine performance has improved by 418 N.%针对2种扩张流道的RBCC燃烧室构型,通过三维数值模拟和地面直连试验,研究了燃烧室结构参数以及火焰稳定装置等对亚燃模态性能的影响。结果表明,第二级燃烧室采用较小的扩张角,有利于燃料的进一步燃烧,减小总压损失,燃料支板和凹腔火焰稳定器的共同使用,能有效提升燃烧室内的燃烧组织效果,扩展火焰的传播范围;直连试验验证了通过构型的改进,燃烧室性能得到大幅提高,压力积分推力增大了682 N。当凹腔距离燃料支板较近时,火箭关闭之后,燃料能够实现自持燃烧,比冲性能可提高50%。通过减小主支板宽度,在来流Ma=4时,能够更容易在隔离段中建立预燃激波系,保证亚燃燃烧反应更好地进行,燃烧室内推力提高了418 N。

  20. Time-domain analysis of wind-induced buffet and wind-resistant measures for cable-stayed bridge with steel box girder at construction stage%大跨度钢箱梁斜拉桥施工过程风致抖振时域分析及抗风措施

    Institute of Scientific and Technical Information of China (English)

    张茜; 周绪红; 狄谨; 王继承

    2013-01-01

    以杭州湾跨海大桥北通航孔斜拉桥为背景,采用ANSYS有限元分析软件对其施工中最大双悬臂及最大单悬臂状态进行了风致抖振响应时域分析.采用谐波合成法进行了随机风场模拟,对塔、梁和索承受的风荷载分别进行了简化,并给出了静风力、抖振力和自激力的时域表达式及自激力在ANSYS中的实现方法;采用“鱼骨式”模型作为斜拉桥主梁的计算模型,分析考虑了结构的几何、气动非线性.分析结果表明:在施工阶段设计风荷载下,主梁悬臂端及塔顶处位移响应较小,风荷载效应与恒载效应组合后,塔根部截面最大拉应力为0.707 MPa;根据抖振响应分析结果和其他因素综合考虑,对杭州湾跨海大桥北通航孔斜拉桥提出了施工过程中有效可行的抗风措施.%Based on the project of north channel cable-stayed bridge of Hangzhou Bay Sea-crossing Bridge, the time-domain analysis of wind-induced buffet was carried out under the double and single jib condition by ANSYS. The random wind field was simulated by WAWS. Buffeting wind loads, which were exerted on tower, girder and cables, were simplified separately. The time-domain expressions of static wind force, buffeting force and full coupled auto-excited force, and how to exert the full coupled auto-excited force in ANSYS were proposed in this paper. Single beam elements were adopted to proceed the time-domain analysis, and the geometric and aerodynamic nonlinear of the structure was considered. Time-domain analysis results show that under the design wind loads at construction stage, the displacement response is smaller at the cantilever end of main girder and the top of pylon. The maximum tensile stress of the section at the root of pylon is 0. 707 MPa after combination of wind loads and dead loads. The wind resistance measures are suggested based on the results of the time-domain analysis and the influence of other factors. 3 tabs, 7 figs, 10

  1. Recent changes in the prevalence of Helicobacter pylori infection among children and adults in high-or low-incidence regions of gastric cancer in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Dong-hong; ZHOU Li-ya; LIN San-ren; DING Shi-gang; HUANG Yong-hui; GU Fang; ZHANG Li; LI Yuan; CUI Rong-li; MENG Ling-mei; YAN Xiue; ZHANG Jing

    2009-01-01

    Background The prevalence of Helicobacter pylori(H.pylon)infection varies by geographic locations.Studies indicate that the infection rate of H.pylori was previously high in China but that rates had been declining worldwide over recent decades.The aims of our study were:(1)to determine the current prevalence of H.pylori infection among children and adults residing in areas with high(Muping County,Shandong)and low(Yanqing County,Beijing)incidences of gastric cancer in China,and(2)to compare the prevalence for 2006 with the prevalence for the early 1990s.Methods Using Warthin-Starry silver staining of gastdc mucosal biopsy specimens and H.pylori stool antigen tests (HpSA),we tested a total of 2065 asymptomatic children aged 8-15 years and adults aged 40-79 years in the above two regions from May to July 2006.We evaluated 520 children and 526 adults from Muping,and 516 children and 503 adults from Yanqing.Subjects were selected randomly and H.pylon status was determined by HpSA in children and either HpSA or histology of gastric biopsies in adults.Data obtained in the early 1990s in the same two areas of China were also collected and studied.Results For children,the prevalence of H.pylori infection was significantly higher in Muping(37.69%)than it was in Yanqing(25.58%,P<0.001).In both regions,the prevalence of H.pylori increased with age but was not related to gender.A significant difference was observed between 8-9-years old and 10-11-years old(P<0.05),but not between other adjoining age groups(P>0.05).From 1991 to 2006 H.py/ori prevalence among 8-10-year-old children decreased in Muping(60.00%vs 32.07%,P<0.001),but not Yanqing(24.06%vs 19.10%,P>0.05).In the adult group,H.pylori prevalence was 50.95%in Muping,which was significantly higher than the 41.35%positive rate in Yanqing(P<0.01).But there were no statistically significant differences between different age groups of 40-49,50-59,and 60-79 years,or between males and females.A significant decrease in

  2. Analysis of Static, Dynamic and Seismic Performance of Long Span Irregular-Shape Pedestrian Cable-Stayed Bridge%大跨人行异型斜拉桥静、动力及抗震性能分析

    Institute of Scientific and Technical Information of China (English)

    刘世明; 赵顺波; 李晓克

    2012-01-01

    为研究异型斜拉桥结构安全,静、动力以及抗震性能是否满足规范要求,以某大跨人行异型斜拉桥为工程背景,采用MIDAS Civil有限元分析软件,结合桥梁施工方法,对结构进行了考虑混凝土的收缩、徐变、温度等作用的静力特性及动力特性、空气动力稳定以及抗震性能分析.结果表明:塔、梁各截面承载力均满足规范要求;结构基本周期比较短,能减少结构的地震位移,但对桥塔底部受力不利,主梁竖向弯曲的第1阶频率不符合规范(大于3 Hz)要求,需要进行特殊设计,自振特性表现出明显的相互耦合的特点,随着频率的提高,结构扭转所占比重增大,对该桥的横向稳定不利;空气动力稳定良好;在E1地震作用下,结构的应力响应较小,结构刚度较大.%To study the structural safety of long span irregular-shape pedestrian cable-stayed bridge and to check if the static, dynamic and seismic performance of the bridge can meet the relevant requirements in the codes, an actual pedestrian cable-stayed bridge of the same type was cited as an example. By means of the finite element analysis software MIDAS Civil and with reference to the construction methods to be used for the bridge, the static and dynamic characteristics, the aerodynamic stability and seismic performance of the structure were analyzed, taking into account of the action of concrete shrinkage, creep and temperatures. The results of the analysis indicate that the bearing capacity of various sections of the pylon and girder of the structure can meet the requirements in the codes, the basic period of the structure is short and can reduce the displacement of the structure caused by earthquake, but it is unfavorable to the force conditions of the pylon footing. The 1st order frequency of vertical bending of the main girder does not meet the requirements (greater than 3 Hz) in the codes and should be specially dealt with in the design. The

  3. Construction Technique for Accurate Positioning of Large Steel Boxed Cofferdam Using Pulling and Berthing Pier System%大型钢吊箱拉靠墩系统精确定位施工技术

    Institute of Scientific and Technical Information of China (English)

    陈超华; 徐斯林; 穆清君

    2011-01-01

    The main bridge of Wuhan Erqi Changjiang River Bridge is a three-pylon composite girder cable-stayed bridge. The pile cap of pylon pier No. 3 of the bridge is located in deepwater and was constructed in dry environment in large steel boxed cofferdam. To resolve the problem of accurate positioning of the large cofferdam, the pulling and berthing pier system was used after comparison of the different positioning schemes. The pier system is composed of a pulling pier at the upstream side and a berthing pier at the downstream side, on the pulling pier, the main pulling cables and tie-down cables were set while on thg berthing pier, the crisscross pulling cables were set. The positioning anchors were cast into the river longitudinally along the bridge and the side anchoring cables were set. After construction preparation, the cofferdam was initially posi-tioned by the pulling and berthing pier system to make the cofferdam basically set in place in plan position. By using the side anchoring cables, pulling cables and by means of non-uniform pumping of water into the bulks of the cofferdam, the plan position, plan torsion, oscillation and perpendicularity of the cofferdam were adjusted and the plan offsetting of the cofferdam was brought to be within +12 mm, the torsional angle to be 58" and the inclination to be 1/3 000 so as to make the construction of the cofferdam meet the relevant requirements in the codes and eventually realize the accurate positioning of the cofferdam.%武汉二七长江大桥主桥为三塔结合梁斜拉桥,其3号墩位于深水中,采用钢吊箱实现承台干施工.为解决大型钢吊箱精确定位难题,经过方案比选,采用拉靠墩系统定位方案,该系统由上游拉墩和下游靠墩组成,拉墩设主拉缆和下拉缆,靠墩设交叉拉缆,顺桥向抛锚,设置边锚缆.施工准备后,利用拉靠墩系统进行钢吊箱初定位,使其平面位置基本就位;通过边锚缆系统、拉缆系统及夹壁舱不均衡灌

  4. Mechanical characterization and validation of poly (methyl methacrylate)/multi walled carbon nanotube composite for the polycentric knee joint.

    Science.gov (United States)

    Arun, S; Kanagaraj, S

    2015-10-01

    Trans femoral amputation is one of the most uncomfortable surgeries in patient׳s life, where the prosthesis consisting of a socket, knee joint, pylon and foot is used to do the walking activities. The artificial prosthetic knee joint imitates the functions of human knee to achieve the flexion-extension for the above knee amputee. The objective of present work is to develop a light weight composite material for the knee joint to reduce the metabolic cost of an amputee. Hence, an attempt was made to study the mechanical properties of multi walled carbon nanotubes (MWCNT) reinforced Poly (methyl methacrylate) (PMMA) prepared through melt mixing technique and optimize the concentration of reinforcement. The PMMA nanocomposites were prepared by reinforcing 0, 0.1, 0.2, 0.25, 0.3 and 0.4 wt% of MWCNT using injection moulding machine via twin screw extruder. It is observed that the tensile and flexural strength of PMMA, which were studied as per ASTM D638 and D790, respectively, were increased by 32.9% and 26.3% till 0.25 wt% reinforcement of MWCNT. The experimental results of strength and modulus were compared with theoretical prediction, where a good correlation was noted. It is concluded that the mechanical properties of PMMA were found to be increased to maximum at 0.25 wt% reinforcement of MWCNT, where the Pukanszky model and modified Halpin-Tsai model are suggested to predict the strength and modulus, respectively, of the PMMA/MWCNT composite, which can be opted as a suitable materiel for the development of polycentric knee joint.

  5. Pragmatic service development and customisation with the CEDA OGC Web Services framework

    Science.gov (United States)

    Pascoe, Stephen; Stephens, Ag; Lowe, Dominic

    2010-05-01

    The CEDA OGC Web Services framework (COWS) emphasises rapid service development by providing a lightweight layer of OGC web service logic on top of Pylons, a mature web application framework for the Python language. This approach gives developers a flexible web service development environment without compromising access to the full range of web application tools and patterns: Model-View-Controller paradigm, XML templating, Object-Relational-Mapper integration and authentication/authorization. We have found this approach useful for exploring evolving standards and implementing protocol extensions to meet the requirements of operational deployments. This paper outlines how COWS is being used to implement customised WMS, WCS, WFS and WPS services in a variety of web applications from experimental prototypes to load-balanced cluster deployments serving 10-100 simultaneous users. In particular we will cover 1) The use of Climate Science Modeling Language (CSML) in complex-feature aware WMS, WCS and WFS services, 2) Extending WMS to support applications with features specific to earth system science and 3) A cluster-enabled Web Processing Service (WPS) supporting asynchronous data processing. The COWS WPS underpins all backend services in the UK Climate Projections User Interface where users can extract, plot and further process outputs from a multi-dimensional probabilistic climate model dataset. The COWS WPS supports cluster job execution, result caching, execution time estimation and user management. The COWS WMS and WCS components drive the project-specific NCEO and QESDI portals developed by the British Atmospheric Data Centre. These portals use CSML as a backend description format and implement features such as multiple WMS layer dimensions and climatology axes that are beyond the scope of general purpose GIS tools and yet vital for atmospheric science applications.

  6. UAV-Based Oblique Photogrammetry for Outdoor Data Acquisition and Offsite Visual Inspection of Transmission Line

    Directory of Open Access Journals (Sweden)

    San Jiang

    2017-03-01

    Full Text Available Regular inspection of transmission lines is an essential work, which has been implemented by either labor intensive or very expensive approaches. 3D reconstruction could be an alternative solution to satisfy the need for accurate and low cost inspection. This paper exploits the use of an unmanned aerial vehicle (UAV for outdoor data acquisition and conducts accuracy assessment tests to explore potential usage for offsite inspection of transmission lines. Firstly, an oblique photogrammetric system, integrating with a cheap double-camera imaging system, an onboard dual-frequency GNSS (Global Navigation Satellite System receiver and a ground master GNSS station in fixed position, is designed to acquire images with ground resolutions better than 3 cm. Secondly, an image orientation method, considering oblique imaging geometry of the dual-camera system, is applied to detect enough tie-points to construct stable image connection in both along-track and across-track directions. To achieve the best geo-referencing accuracy and evaluate model measurement precision, signalized ground control points (GCPs and model key points have been surveyed. Finally, accuracy assessment tests, including absolute orientation precision and relative model precision, have been conducted with different GCP configurations. Experiments show that images captured by the designed photogrammetric system contain enough information of power pylons from different viewpoints. Quantitative assessment demonstrates that, with fewer GCPs for image orientation, the absolute and relative accuracies of image orientation and model measurement are better than 0.3 and 0.2 m, respectively. For regular inspection of transmission lines, the proposed solution can to some extent be an alternative method with competitive accuracy, lower operational complexity and considerable gains in economic cost.

  7. Cracking resistance performance of super vertical-distance pumped SFRC

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The mix ratio of steel fiber reinforced concrete(SFRC)was optimized using the principles that workability must meet the pumping demand and anti-cracking performance should be optimal.The effect of SFRC on the initial cracking load,the ultimate load and the crack width of the reinforced concrete (RC) member were analyzed in this paper.It was found that the admixture had good preservation of moisture and adhesion and the fibers distributed homogeneously in one hour out of the machine.According to the pumping results,the SFRC could be pumped vertically up to 306 m.Based on the standard computation formula of cracks,the maximum crack width of an RC member with 0.8% steel fiber (by volume) is about 32% lower than that of standard RC member.Through an experimental research on full-scale model tests for the steel and concrete composite anchorage zone on a pylon,the SFRC not only remarkably increases the crack resistance and the ultimate load,but the initial load also improves 33% approximately.It is also indicated that plastic shrinkage cracking of SFRC in which volume fraction of steel fibers is 0.8% can be restrained obviously and the unrestrained drying shrinkage can be diminished by about 50% at early age.The results confirmed that the SFRC can lessen the shrinkage crack of concrete and enhance markedly the direct tensile strength.Therefore,the SFRC can solve the key question of crack resistance for the anchorage zone of a bridge tower.

  8. Airborne multi-axis DOAS measurements of atmospheric trace gases on CARIBIC long-distance flights

    Directory of Open Access Journals (Sweden)

    B. Dix

    2009-11-01

    Full Text Available A DOAS (Differential Optical Absorption Spectroscopy instrument was implemented and operated onboard a long-distance passenger aircraft within the framework of the CARIBIC project (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container. The instrument was designed to keep weight, size and power consumption low and to comply with civil aviation regulations. It records spectra of scattered light from three viewing directions (nadir, 10° above and below horizon using a miniaturized telescope system. The telescopes are integrated in the main pylon of the inlet system which is mounted at the belly of the aircraft. Fibre bundles transmit light from the telescopes to spectrograph-detector units inside the DOAS container instrument. The latter is part of the removable CARIBIC instrument container, which is installed monthly on the aircraft for a series of measurement flights.

    During 30 flight operations within three years, measurements of HCHO, HONO, NO2, BrO, O3 and the oxygen dimer O4 were conducted. All of these trace gases except BrO could be analysed with a 30 s time resolution. HONO was detected for the first time in a deep convective cloud over central Asia, while BrO, NO2 and O3 could be observed in tropopause fold regions. Biomass burning signatures over South America could be seen and measurements during ascent and descent provided information on boundary layer trace gas profiles (e.g. NO2 or HCHO.

  9. Solving Man-Induced Large-Scale Conservation Problems: The Spanish Imperial Eagle and Power Lines

    Science.gov (United States)

    López-López, Pascual; Ferrer, Miguel; Madero, Agustín; Casado, Eva; McGrady, Michael

    2011-01-01

    Background Man-induced mortality of birds caused by electrocution with poorly-designed pylons and power lines has been reported to be an important mortality factor that could become a major cause of population decline of one of the world rarest raptors, the Spanish imperial eagle (Aquila adalberti). Consequently it has resulted in an increasing awareness of this problem amongst land managers and the public at large, as well as increased research into the distribution of electrocution events and likely mitigation measures. Methodology/Principal Findings We provide information of how mitigation measures implemented on a regional level under the conservation program of the Spanish imperial eagle have resulted in a positive shift of demographic trends in Spain. A 35 years temporal data set (1974–2009) on mortality of Spanish imperial eagle was recorded, including population censuses, and data on electrocution and non-electrocution of birds. Additional information was obtained from 32 radio-tracked young eagles and specific field surveys. Data were divided into two periods, before and after the approval of a regional regulation of power line design in 1990 which established mandatory rules aimed at minimizing or eliminating the negative impacts of power lines facilities on avian populations. Our results show how population size and the average annual percentage of population change have increased between the two periods, whereas the number of electrocuted birds has been reduced in spite of the continuous growing of the wiring network. Conclusions Our results demonstrate that solving bird electrocution is an affordable problem if political interest is shown and financial investment is made. The combination of an adequate spatial planning with a sustainable development of human infrastructures will contribute positively to the conservation of the Spanish imperial eagle and may underpin population growth and range expansion, with positive side effects on other endangered

  10. Determination of Radon concentration in air using scinti-cell radon monitor

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Taeko [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst; Morishima, Hiroshige; Arai, Naoki; Shiraishi, Masatoshi; Shigehara, Makiko [Dept. of Nuclear Engineering, School of Science and Technology, Kinki Univ., Higashi-Osaka, Osaka(Japan); Mifune, Masaaki

    2000-01-01

    This study is carried out the methodology characteristics of {sup 222}Rn (Radon) concentration in air using the scinti-cell radon monitor (Trace environmental level detector (PMT-TEL) and Lucas cell (300 A), Pylon Co. and the determination of Radon concentrations in air on Misasa spa area in Tottori pref. and Ikeda spa in Shimane pref. on November 1995 and 1996. We have reached to the following results; (1) Minimum detectable Radon concentrations in air using the scinti-cell monitor are 7.6 Bq/m{sup 3} with 23% of accuracy (relative standard deviation) on the grab sampling of Lucas cell and 0.58 Bq/m{sup 3} with that of 17% on the continuous measuring of PMT-TEL, when it measured after 3.5 hours on the air sampling to determine the mean radon concentrations. The radon concentrations by the PMT-TEL method is about ten times more detectable than those by Lucas cell, that the former is the most sensitive among the detectors used on this research and is able to detect low level environmental concentrations, particularly outdoor and the later is valuable to use conveniently and portably on grab spot sampling of high level radon concentrations indoor air. (2) On the comparison of characteristics on spot monitoring of radon in air, a pico-rad method is suitable for the determination of the mean concentration for continuous sampling period by PMT-TEL and Lucas cell 300 A, and the variation of radon concentration can be observed on elapse of time course. (author)

  11. 带控制律导弹投放数值模拟%Missile separation simulation with control laws

    Institute of Scientific and Technical Information of China (English)

    周乃春; 李彬; 郑鸣; 邓有奇

    2013-01-01

    Using an overset unstructured grid,three dimensional URANS equations are applied to simulate the missile separation with control laws.The walls criterion is used in the automatic hole-cutting procedure.Arithmetic average method is used to get the value during the overset grids.Comparison computing of the trajectories of a wing/pylon/finned-store configuration with three different control laws is carried out with this method,and a complex separation problem is solved.%基于非结构重叠网格技术,耦合舵面控制律模块,采用非定常雷诺平均NS方程,建立了模拟控制律作用下导弹投放分离动态特性的CFD数值方法.非结构重叠网格生成技术以“物面相交”方法确定洞边界,在多套网格重叠部分采用算术平均进行物理量的计算传递.采用机翼/挂架/带舵外挂物模型,以及不同的舵面控制规律展开了对比计算,分析了结果.并比较了某导弹有无控制律作用时从某战斗机分离的动态特性,研究了增加控制律的必要性.

  12. 转子陀螺效应对翼吊发动机机翼弯扭颤振特性影响研究%Gyroscopic effects on the engine rotor on the characteristics of wing bending-torsional flutter

    Institute of Scientific and Technical Information of China (English)

    周健斌; 章俊杰; 孟光

    2012-01-01

    针对现代翼吊式机翼发动机系统的特点,考虑发动机陀螺效应对系统结构动力学特性的影响,建立了基于梁振动理论的机翼弯扭颤振方程;分析了陀螺效应对系统颤振特性的影响规律.结果表明:不考虑发动机吊挂刚度影响时,陀螺效应不影响系统弯扭颤振发生机理,系统颤振速度和颤振频率随着发动机转速的提高而增大;转子陀螺效应对机翼弯扭颤振特性的影响可等效为系统阻尼,且该等效阻尼亦随着发动机转速的提高而增大.%Bending-torsional flutter equations of a wing-engine system have been derived, taking into account of the gyroscopic effects of the engine rotor on the wing structure. The connection between the wing and the engine was assumed to be stiff in the equation. Flutter characteristics of the wing with gyroscopic effect was analyzed. The results showed that, with the stiffness of the pylon ignored, the gyroscopic moment raised the flutter speed and flutter frequency of the system, whilst it didn t affect the inherent flutter mechanism. As a result, the gyroscopic effect on the flutter of the wing-engine system could be effectively modeled as a system damping, and the equivalent damping ratio rose with the rotational speed of the engine.

  13. Parallel WENO Scheme for Three-Dimensional Steady Viscous Fluid Computation%并行WENO格式在三维定常粘性流体计算中的应用

    Institute of Scientific and Technical Information of China (English)

    叶钦巴图; 胡晓东; 张鉴; 陆忠华; 李新亮

    2013-01-01

    WENO (Weighted Essentially Non-Oscillatory) is a popular high precision scheme in CFD. In this paper, WEDO is introduced into large-scale parallel simulation. The simulation tests for ONERA-M6 Wing, DLR-F6 Body/Wing and DLR-F6 Body/Wing/Nacelle/Pylon modes are performed with the implicit WENO 3-order and WENO 5-order schemes. The number of compute nodes is ranged from 64 to 1024. The comparison of calculation with experimental results shows that the WENO schemes in massively parallel computing can effectively play its advantages of high-precision, and get good results in shock wave and vortex lfow simulation.%我们将目前计算流体力学中比较流行的高精度WENO (Weighted Essentially Non-Oscillatory)格式引入到大规模并行计算求解中,使用隐式WENO3阶格式和WENO5阶格式对ONERA-M6翼型和DLR-F6机身/机翼以及DLR-F6机身/机翼/发动仓/吊架模型进行了模拟测试。并行规模从64核到1024核。通过数值计算结果和实验结果的对比分析,得出WENO格式在大规模并行计算中能够有效的发挥其高精度的优势,对于激波捕获和涡脱离流动的模拟中能够获得较好的模拟效果。

  14. 飞机外挂物投放安全性的参数影响分析%Parameter analysis of safety in store separation

    Institute of Scientific and Technical Information of China (English)

    聂璐; 向锦武

    2011-01-01

    The trajectory of external stores separating from aircraft was computed in different flight conditions with the quasi-steady method. In every step, the flow fields of external stores and aircraft were regarded as steady and the aerodynamic forces acting on stores were calculated with the CFD method while keeping in the aircraft flight initial states. A 6 DOF rigid body model was used to compute the trajectory resulting from the combination of the stores mass properties and aerodynamic loading. Separation of a generic wing-pylon-store configuration was given and comparisons were demonstrated in flight states of different Mach number, altitude and attitude of aircraft. The safe separating effected by elements was concluded, and suggestions about risk-reduction were given.%研究了飞机在不同飞行高度、速度和姿态下,不同外挂物质量对投放安全性的影响.采用CFD方法计算外挂物所受气动力,通过六自由度刚体动力学方程计算外挂物的投放轨迹和姿态变化.准定常方法在计算外挂物下落轨迹的每个步长内,认为外挂物和载机都处在定常流场中,载机在投放过程中保持原有运动状态.通过算例给出了典型外挂物在不同速度、高度、姿态下投放的运动轨迹,分析了对安全投放有重要影响的因素,提出了减少外挂物投放风险的建议.

  15. Preliminary Investigation on Flow Control Mechanisms of Nacelle Strake%短舱涡流发生器流动控制机理初探

    Institute of Scientific and Technical Information of China (English)

    孙一峰; 杨士普

    2012-01-01

    首先回顾了短舱涡流发生器在民机研制中的应用及发展历程,然后结合民用飞机研发实践,借助于CFD工具初步计算并着重分析了短舱涡流发生器的流动控制机理。结果分析表明合理设计的短舱涡流发生器能够产生能量较强的集中涡,在分离敏感的短舱后翼面区域产生下洗流场并为边界层注入能量,降低短舱后气流的当地有效迎角,延缓由于“挂架涡”提前破裂而导致的大面积分离,从而能够改善失速区形态。%Applications and developments of a kind of vortex control device, the nacelle strake, are first reviewed. Underlying flow control mechanisms are then demonstrated through CFD simulations. Once the nacelle strake is properly designed and installed, strong vortices shed from the strake can produce upwashes and reenergize the separation-sensitive boundary layer on the upper wing behind the nacelle. The stall characteristics are improved by lowering the effective angle of attack and delaying premature bursts of the pylon vortex.

  16. Report on the evaluation of the VA/Seattle below-knee prosthesis.

    Science.gov (United States)

    Ellepola, W; Sheredos, S J

    1993-01-01

    The Department of Veterans Affairs (VA), Rehabilitation Research and Development (Rehab R&D) Service, Technology Transfer Section (TTS) with collaboration from the Prosthetic and Sensory Aids Service (PSAS) managed clinical trials to evaluate the VA/Seattle Below-Knee (BK) Prosthetic System. The clinical trials were held at the Prosthetic Treatment Center (PTC), VA Medical Center, Hines, Illinois. Five other VA medical centers participated in the outreach program of the trials as satellite stations, with PTC Hines as the central fabrication facility. The VA/Seattle BK system is the first complete prosthetic system designed and developed by the Department of Veterans Affairs. It consists of a socket designed and fabricated using computer-aided, automated technology, and off-the-shelf modular components: a lightweight pylon and an ankle unit, and a lightweight, energy-storing foot. The computer-based socket design software, the modular components, and the prosthetic foot were developed with funds from the VA Rehab R&D Service. The evaluation trials were conducted to determine the efficacy of the VA/Seattle prosthesis, its reliability, and acceptance by veterans. The clinical trials began in April 1991 and were completed in August 1992. Forty-six BK amputee veterans were fitted with the VA/Seattle prosthesis. Their progress with the prosthesis was followed for a period of 6 months and data were gathered at intervals of 2 weeks, 3 months, and 6 months. Forty sets of subject data instruments were collected. In order to maintain the accuracy of the results, TTS used the 22 sets that were complete for data analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Dynamic study of a wind turbine blade with horizontal axis

    Energy Technology Data Exchange (ETDEWEB)

    Yousi, R.; El-Batanony, I.; Tritsch, J.B.; Naji, H.; Landjerit, B. [EUDIL, Dept. Mecanique, LML, CNRS URA 1441, 59 - Villeneuve d' Ascq (France)

    2001-04-01

    The study of the dynamic behavior of a wind turbine with horizontal axis can be undertaken by various methods of analysis. The effects of the change of the aerodynamic flow (in the steady and unsteady cases), the variation of parameters of the cinematic movement (angle of attack, pitch angle and yaw angle) and the definition of subsystems characteristics that makes the wind turbine (blade, nacelle and pylon) allow one to characterize the structural dynamic behavior of the wind turbine. It is therefore necessary to develop these items. Once this is done, the structural dynamic behavior of the system can be improved. The term 'improve' means the increase of the life duration by mastering the fatigue effects and the reduction of cost without sacrificing the aerodynamic output. The present study aims to examine the behavior of the blade, which is the main part of the wind turbine in that it that transmits forces to all other parts of the structure. The model is based on the theory of three-dimensional beams, under the assumption of variable sections of the type NACA 4415 airfoil, and takes into account membrane, transversal shear, flexion and free torsion effects. With regards to the aerodynamic loads (the lift, the drag and the pitching moment), a validation has been undertaken by considering experimental data and numerical results obtained by a CFD code (Fluent). The forces are obtained by means of a parametric CAD method interpolation of the aerodynamic poles by Bezier patch under geometrical constraints solved by a Simplex type algorithm. The emphasis is put on dynamic aspects by a complete processing of the dynamic equilibrium equation, applied to the wind turbine blade with horizontal axis. (authors)

  18. Constrained Multipoint Aerodynamic Shape Optimization Using an Adjoint Formulation and Parallel Computers

    Science.gov (United States)

    Reuther, James; Jameson, Antony; Alonso, Juan Jose; Rimlinger, Mark J.; Saunders, David

    1997-01-01

    complete configuration designs subject to multiple design points and geometric constraints. Examples are presented for both transonic and supersonic configurations ranging from wing alone designs to complex configuration designs involving wing, fuselage, nacelles and pylons.

  19. Multi-Body Analysis of a Tiltrotor Configuration

    Science.gov (United States)

    Ghiringhelli, G. L.; Masarati, P.; Mantegazza, P.; Nixon, M. W.

    1997-01-01

    The paper describes the aeroelastic analysis of a tiltrotor configuration. The 1/5 scale wind tunnel semispan model of the V-22 tiltrotor aircraft is considered. The analysis is performed by means of a multi-body code, based on an original formulation. The differential equilibrium problem is stated in terms of first order differential equations. The equilibrium equations of every rigid body are written, together with the definitions of the momenta. The bodies are connected by kinematic constraints, applied in form of Lagrangian multipliers. Deformable components are mainly modelled by means of beam elements, based on an original finite volume formulation. Multi-disciplinar problems can be solved by adding user-defined differential equations. In the presented analysis the equations related to the control of the swash-plate of the model are considered. Advantages of a multi-body aeroelastic code over existing comprehensive rotorcraft codes include the exact modelling of the kinematics of the hub, the detailed modelling of the flexibility of critical hub components, and the possibility to simulate steady flight conditions as well as wind-up and maneuvers. The simulations described in the paper include: 1) the analysis of the aeroelastic stability, with particular regard to the proprotor/pylon instability that is peculiar to tiltrotors, 2) the determination of the dynamic behavior of the system and of the loads due to typical maneuvers, with particular regard to the conversion from helicopter to airplane mode, and 3) the stress evaluation in critical components, such as the pitch links and the conversion downstop spring.

  20. Helicobacter pylori-related immunoglobulins in sarcoidosis.

    Science.gov (United States)

    Herndon, Betty L; Vlach, Victoria; Dew, Michelle; Willsie, Sandra K

    2004-03-01

    The purpose of this study was to determine serum antibody titers against a common bacterial antigen, Helicobacter pylori (H. pylon), in subjects with sarcoidosis, comparing those titers to those present in a healthy population. With the approval of the Institutional Review Board of the University of Missouri-Kansas City, patients with sarcoidosis (pulmonary and extrapulmonary) who visited the Truman Medical Center-Hospital Hill pulmonary clinic were recruited to enter the study. A serum sample was frozen at -70 degrees C for later testing (n = 20). Specific information collected on subjects included corticosteroid use, use of histamine2 blockers and antacids, date of first diagnosis, and stage of sarcoidosis. Normal controls and demographically matched individuals who lacked pulmonary diseases, including sarcoidosis, were also recruited. Serum samples were processed as above. Antibody capture enzyme immunoassay was completed for H. pylori and urease antigens by serum dilution assay for each subject, from which titers for antigen-specific immunoglobulin (Ig)G and IgA were calculated. Nonspecific serum IgE was also measured. An increased incidence of high-titer IgG antibody directed against H. pylori antigens was found in subjects with sarcoidosis compared with controls. The sarcoidosis and control groups were significantly different with respect to IgG and IgA against H. pylori, both at p = .001. IgG directed against urease was also significantly different between sarcoidosis and control patients (p = .001), but IgA directed against urease was very low in all subjects and did not yield significant differences between groups. Specific H. pylori and urease IgG antibodies exceeded those expected in the population studied. The data suggest that in pulmonary sarcoidosis, the relationship of H. pylori and its products to sarcoid granuloma formation warrants further investigation.

  1. Comparison of the diagnostic performance of {sup 14}C-urea breath test according to counting method for the diagnosis of Helicobacter pylori infection

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Woo; Lim, Seok Tae; Lee, Seung Ok; Sohn, Myung Hee [Chonbuk National University Medical School, Chonju (Korea, Republic of)

    2005-02-15

    {sup 14}C-urea breath test (UBT) is a non-invasive and reliable method for the diagnosis of Helicobacter pylon, (HP) infection. In this study, we evaluated the diagnostic performance of a new and rapid {sup 14}C-UBT (Heliprobe method), which was equipped with Geiger-Muller counter and compared the results with those obtained by using the conventional method. Forty-nine patients with dyspepsia underwent gastroduodenoscopy and {sup 14}C-UBT. A 37 KBq {sup 14}C-urea capsule was administered to patients and breath samples were collected. In Heliprobe method, patients exhaled into a Heliprobe BreathCard for 10 min. And then the activities of the BreathCard were countered using Heliprobe analyzer. In the conventional method, results were countered using liquid scintillation counter. During gastroduodenoscopy, 18 of 49 patients were underwent biopsies. According to these histologic results, we evaluated the diagnostic performance of two different methods and compared them. Also we evaluated the concordant and disconcordant rates between them. In all 49 patients, concordant rate of both conventional and Heliprobe methods was 98% (48/49) and the discordant rate was 2% (1/49). thirteen of 18 patients to whom biopsies were applied, were found to be HP positive on histologic results. And both Heliprobe method and conventional method classified 13 of 13 HP-positive patients and 5 of 5 HP-negative patients correctly (sensitivity 100%, specificity 100%, accuracy 100%). The Heliprobe method demonstrated the same diagnostic performance compared with the conventional method and was a simpler and more rapid technique.

  2. Cytotoxin-associated gene-A-seropositive virulent strains of Helicobacter pylori and atherosclerotic diseases: a systematic review

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shuo; GUO Yang; MA Yan; TENG Yue

    2008-01-01

    Objective A systematic meta-analysis was performed to explore the role of cytotoxin-associated gene-A (CagA)seropositive strains of Helicobacterpylori (H. pylon) in the pathogenesis of atherosclerotic diseases.Data sources Data from Medline, EMBASE, CBMdisc, CNKI and the Cochrane Collaboration database were searched.Similar search strategies were applied to each of these databases.Study selection The review was restricted to the case-control studies on infective, chronic virulent CagA strains of H.pylori, involving the risk of ischemic stroke and coronary heart disease, ineligible studies were excluded. Two reviewers independently extracted the data and assessed study quality.Results Totally 26 case-control studies (11 studies on ischemic stroke and 15 studies on coronary heart disease) were retrieved and considered. The combined data revealed that the chronic seropositive virulent strains of H. pylori infection had a trend of increasing the risk of ischemic strokes and coronary heart diseases, yielding pooled Ors of 2.68 (95% CI: 2.20, 3.27)and 2.11 (95% CI: 1.70, 2.62), respectively. We also performed subgroup analyses, dividing the total population into Caucasian and Chinese subgroups. Through the subgroup analysis, no significant difference was found between the subgroups.Conclusions Our results support the hypothesis that CagA-seropositive strains infection is significantly associated with susceptibility to ischemic strokes and coronary heart diseases. The magnitude of the association with atherosclerotic diseases needs to be confirmed by prospective studies and the studies on CagA-seropositive strains eradication are more important.

  3. Indoor radon measurements in dwellings and other buildings in the metropolitan region of Belo Horizonte, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Talita de Oliveira [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil)]. E-mail: talitaolsantos@yahoo.com.br; Rocha, Zildete [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Servico de Quimica e Radioquimica]. E-mail: rochaz@cdtn.br

    2007-07-01

    Radon is a radioactive noble gas derived from the natural decay series of {sup 238}U, {sup 235}U, and {sup 232}Th, which are present in rocks and soils. By diffusion and convection, radon migrates from the rocks and soils to the surface and through fissures, pipes and holes it may enter the dwellings and other buildings. Another important indoor radon source is the building material construction. Therefore, it may accumulate indoor environments with reduced ventilation rates. Radon progeny attach to the aerosol particle in the air. The attached and unattached radon progeny may deposit in the lungs and irradiate to the lung tissue as they decay. Radon has been recognized as a radiation hazard, that causes excess of lung cancer among underground miners and there is an evidence that radon is also a heath hazard in dwellings and other indoor environments. Radon accounts for about half of all human exposure to natural radiation. Radon concentration measurements were carried out in dwellings, schools and shopping centers in the Metropolitan Region of Belo Horizonte - RMBH. Most part of the inhabitants of the RMBH lives over the granitic gneissic complex, which has a variable depth out coming in some areas. For the radon concentration measurement continuous detectors, AlphaGUARD PQ2000PRO, RAD7 and Pylon Lucas Cells were used and, for Potential Alpha Energy Concentration-PAEC measurement a solid state alpha spectroscope, the DOSEman PRO was used. The experiments showed that most results are below 50 Bqm{sup -3} (mean+3{sigma}). This value is bellowing the action levels of the USEPA, ICRP and others, which varies in the range from 148 to 200 Bqm{sup -3}. The values are in the low range, as it was expected for a tropical climate. (author)

  4. Computation of wind-induced vibrations of flexible shells and membranous structures

    Science.gov (United States)

    Glück, M.; Breuer, M.; Durst, F.; Halfmann, A.; Rank, E.

    2003-04-01

    A partitioned coupling approach for time-dependent fluid-structure interactions is applied to thin shells and membranous structures with large displacements. The frame algorithm connects a three-dimensional, finite volume-based multi-block flow solver for incompressible fluids with a finite element code for geometrically nonlinear structural problems using a commercial coupling interface. Thus a high modularity is achieved and the whole range of opportunities with these two powerful codes - each of them highly adapted to its specific field of application - can be used also for coupled simulations. Two completely different configurations were investigated. First, the coupling algorithm was applied to an academic test configuration consisting of one, two, and three flexible L-shaped plates being loaded by a steady far-field flow. Various investigations were carried out at different Reynolds numbers /(Re=50,200, and 500) in order to study phenomena such as vortex shedding, resonance, influence of the interaction between several flexible plates, whereas the second and third plates were placed in the wake of the first. The second part of the paper shows that in principle the coupling procedure can also deal with real-life structures as they occur in civil engineering. A membranous roof of glass-fiber synthetics with a complex shape was exposed to a time-dependent wind gust from diagonally above which was superimposed on a constant basic wind flow parallel to the ground. The structural model contains the pre-stressed textile roof including the taut cables at its circumference which are fastened at the pylons. As a structural response, the wind gust led to a displacement of the textile roof which disappeared again when the gust subsided. With the coupled algorithm proposed in the paper it is possible to study dynamic interactions for engineering applications.

  5. New study on the correlation between carbon dioxide concentration in the environment and radon monitor devices.

    Science.gov (United States)

    Shahrokhi, A; Burghele, B D; Fábián, F; Kovács, T

    2015-12-01

    The influence of high geogenic carbon dioxide concentrations on monitoring devices might present a significant challenge to the measurement of radon concentrations in environments with a high level of carbon dioxide concentration such as volcano sites, mofettes, caves, etc. In this study, the influence of carbon dioxide concentration on several different types of radon monitor devices - including Alpha Spectrometry (Sarad RTM 2200, EQF 3220, RAD7), Ionizing Chamber (AlphaGUARD PQ2000 PRO) and Active Cell (Active scintillation cell, Pylon 300A) - was examined to represent new aspects of radon measuring in environments with carbon dioxide. In light of the results, all measuring devices were exposed to variable conditions affected by carbon dioxide concentration, except for the AlphaGUARD, which was kept in a steady state throughout the experiment. It was observed that alpha spectroscopy devices were affected by carbon dioxide, since measured radon concentrations decreased in the presence of 70% and 90% carbon dioxide concentrations by 26.5 ± 2% and 14.5 ± 2.5% for EQF 3220, and 32 ± 2% and 35.5 ± 2% for RTM 2200. However, the ionizing chamber instrument was unaffected by changes in carbon dioxide concentration. It was determined that the RAD7 performed relatively inefficiently in the presence of carbon dioxide concentrations higher than 67% by an overall efficiency factor of approximately 0.52, confirming that it is not an admissible radon monitor instrument in environments with high carbon dioxide concentrations.

  6. Hybrid Fuzzy Control of Semi-active Suspension System%半主动悬架系统的混合模糊控制

    Institute of Scientific and Technical Information of China (English)

    黄晨; 陈龙; 袁朝春; 江浩斌; 牛礼明

    2014-01-01

    According to the requirements on both handling stability and ride comfort performance of vehicle in multi-condition driving,a semi-active suspension control strategy based on hybrid fuzzy control is proposed. A hy-brid controller is designed with Simulink/Stateflow, and with the multi-body dynamics model for a car as example, a SIMPACK/Matlab co-simulation on both random input running test and pylon course slalom test at different speeds is conducted. Finally based on dSPACE and the hardware simulation platform of tested vehicle, a real vehicle sus-pension system test is performed. The results indicate that the hybrid fuzzy control strategy proposed is feasible and can well improve the ride comfort and handling stability of vehicle.%针对汽车多工况行驶对操纵稳定性和平顺性的综合要求,提出了一种基于混合模糊控制的半主动悬架整车控制策略。在Simulink-Stateflow中设计了混合控制器,以某车多体动力学模型为例进行了随机路面和蛇形道路上不同车速下的SIMPACK/Matlab联合仿真,最后基于dSPACE和试验车辆的硬件仿真平台,进行悬架系统实车测试。结果表明,所提出的混合模糊控制是可行的,能较好地改善车辆行驶平顺性和操纵稳定性。

  7. Relation of atrophic gastritis with Helicobacter pylori-CagA+and interleukin-1 gene polymorphisms

    Institute of Scientific and Technical Information of China (English)

    Rafaela Sierra; Francis Mégraud; Clas Une; Vanessa Ramírez; Warner Alpízar-Alpízar; María I González; José A Ramírez; Antoine de Mascarel; Patricia Cuenca; Guillermo Pérez-Pérez

    2008-01-01

    AIM: To determine the association of Helicobacter pylori (H pylon) CagA+ infection and pro-inflammatory poly-morphisms of the genes interleukin (IL)-IRN and IL-1B with the risk of gastric atrophy and peptic ulcers in a dyspeptic population in Costa Rica, a country with high incidence and mortality of gastric cancer. METHODS: Seven biopsy specimens, a fasting blood sample and a questionnaire concerning nutritional and sociodemographic factors were obtained from 501 con-secutive patients who had undergone endoscopy for dyspeptic symptoms. A histopathological diagnosis was made. Pepsinogen concentrations were analyzed by enzyme linked immunosorbent assay (ELISA). Infection with H pylori CagA* was determined by serology and polymerase chain reaction (PCR). IL-1B and IL-1RN polymorphisms genotyping was performed by PCR-restriction fragment length polymorphism (PCR-RFLP) and PCR respectively. RESULTS: In this dyspeptic population, 86% wereHpy/ori positive and of these, 67.8% were positive forCagA. Atrophic antral gastritis (AAG) was associatedwith CagA+ status [odd ratio (OR) = 4.1; P < 0.000]and fruit consumption (OR = 0.3; P < 0.00). Atrophicbody gastritis (ABG) was associated with pepsinogenPGI/PGII < 3.4 (OR = 4.9; P < 0.04) and alcoholconsumption (OR = 7.3; P < 0.02). Duodenal ulcerwas associated with CagA+ (OR = 2.9; P < 0.04) andsmoking (OR = 2.4; P < 0.04). PGI < 60 μg/L as wellas PGI/PGII < 3.4 were associated with CagA+. CONCLUSION: In a dyspeptic population in Costa Rica,H pylori CagA+ is not associated with ABG, but it is arisk factor for AAG. The pro-inflammatory cytokine poly-morphisms IL-1B + 3945 and IL-1RN are not associatedwith the atrophic lesions of this dyspeptic population.

  8. Flight Test Results from the Rake Airflow Gage Experiment on the F-15B

    Science.gov (United States)

    Frederick, Michael; Ratnayake, Nalin

    2011-01-01

    The results are described of the Rake Airflow Gage Experiment (RAGE), which was designed and fabricated to support the flight test of a new supersonic inlet design using Dryden's Propulsion Flight Test Fixture (PFTF) and F-15B testbed airplane (see figure). The PFTF is a unique pylon that was developed for flight-testing propulsion-related experiments such as inlets, nozzles, and combustors over a range of subsonic and supersonic flight conditions. The objective of the RAGE program was to quantify the local flowfield at the aerodynamic interface plane of the Channeled Centerbody Inlet Experiment (CCIE). The CCIE is a fixed representation of a conceptual mixed-compression supersonic inlet with a translating biconic centerbody. The primary goal of RAGE was to identify the relationship between free-stream and local Mach number in the low supersonic regime, with emphasis on the identification of the particular free-stream Mach number that produced a local Mach number of 1.5. Measurements of the local flow angularity, total pressure distortion, and dynamic pressure over the interface plane were also desired. The experimental data for the RAGE program were obtained during two separate research flights. During both flights, local flowfield data were obtained during straight and level acceleration segments out to steady-state test points. The data obtained from the two flights showed small variations in Mach number, flow angularity, and dynamic pressure across the interface plane at all flight conditions. The data show that a free-stream Mach number of 1.65 will produce the desired local Mach number of 1.5 for CCIE. The local total pressure distortion over the interface plane at this condition was approximately 1.5%. At this condition, there was an average of nearly 2 of downwash over the interface plane. This small amount of downwash is not expected to adversely affect the performance of the CCIE inlet.

  9. M2-F3 In-flight Launch from B-52

    Science.gov (United States)

    1971-01-01

    significant research projects in aerospace history. Some of the significant projects supported by B-52 008 include the X-15, the lifting bodies, HiMAT (highly maneuverable aircraft technology), Pegasus, validation of parachute systems developed for the space shuttle program (solid-rocket-booster recovery system and the orbiter drag chute system), and the X-38. The B-52 served as the launch vehicle on 106 X-15 flights and flew a total of 159 captive-carry and launch missions in support of that program from June 1959 to October 1968. Information gained from the highly successful X-15 program contributed to the Mercury, Gemini, and Apollo human spaceflight programs as well as space shuttle development. Between 1966 and 1975, the B-52 served as the launch aircraft for 127 of the 144 wingless lifting body flights. In the 1970s and 1980s, the B-52 was the launch aircraft for several aircraft at what is now the Dryden Flight Research Center, Edwards, California, to study spin-stall, high-angle-of attack, and maneuvering characteristics. These included the 3/8-scale F-15/spin research vehicle (SRV), the HiMAT (Highly Maneuverable Aircraft Technology) research vehicle, and the DAST (drones for aerodynamic and structural testing). The aircraft supported the development of parachute recovery systems used to recover the space shuttle solid rocket booster casings. It also supported eight orbiter (space shuttle) drag chute tests in 1990. In addition, the B-52 served as the air launch platform for the first six Pegasus space boosters. During its many years of service, the B-52 has undergone several modifications. The first major modification was made by North American Aviation (now part of Boeing) in support of the X-15 program. This involved creating a launch-panel-operator station for monitoring the status of the test vehicle being carried, cutting a large notch in the right inboard wing flap to accommodate the vertical tail of the X-15 aircraft, and installing a wing pylon that enables

  10. Treatment Scheme of the West Slope of Sijiaying Iron Mine Stope%司家营铁矿采场西帮边坡治理方案

    Institute of Scientific and Technical Information of China (English)

    杨威; 张云鹏

    2016-01-01

    In order to ensure the mine normal production and the safety of equipment and person-nel,the thickness alluvium slope landslide of N#14 ~N#16 line of the west slope of the first stope of Sijiaying iron mine conducted inversion analysis based on Geo-slope software,the checking calculation is conducted by adopting the circular sliding method to obtain the mechanical parameters of slope soil.Through the e-valuation of slope stability analysis,the two slope treatment schemes are proposed that are the cutting slope and slope toe soil nail reinforcement.The comparison and analysis results show that,the final bot-tom boundary position can not be impacted by the scheme of the soil nail construction to stable the slope rock mass,it also good for avoiding moving the high-pressure pylons and telegraph poles and ensuring the stability of the mine west slope.%为确保司家营铁矿正常生产和人员设备安全,应用 Geo-slope 软件,对该矿一期采场西帮 N#14~N#16线特厚冲积层边坡滑坡进行了反演分析,采用圆弧滑动法进行了验算,得到了边坡土体的力学参数。通过对边坡进行稳定性分析评价,制定了削坡和坡脚土钉加固的2种边坡治理方案,经对比分析,认为土钉施工稳定边坡岩体方案不影响坑底最终境界位置,避免高压线塔和电线杆的移设,有助于确保该矿西帮边坡的稳定。

  11. Comparison of Several Culture Methods for Helicobacter pylori%几种培养幽门螺杆菌方法的比较

    Institute of Scientific and Technical Information of China (English)

    刘琳娜; 丁士刚; 张静; 石岩岩

    2012-01-01

    Helicobacter pylori (H. pylori) is infected in more than half of population in the world, and it is very important to study the culture methods for H. pylori. Aims: To study the effect of different culture medium on growth of H. pylori. Methods: Solid and liquid culture medium were prepared with defibrinated sheep blood and 3 kinds of animal serum (sheep, horse, cattle) for culture of H. pylori. Morphology of bacteria colony, microscopic examination, rapid urease test, PCR assay and concentration of bacteria were used to identify H. pylon. Results: Solid and liquid medium containing defibrinated sheep blood and animal serum could successfully culture H. pylori. H. pylori concentration was the highest in solid media containing defibrinated sheep blood, and culture medium containing horse serum were more satisfactory for the culture of H. pylori. Conclusions: Solid and liquid culture medium can obtain satisfactory culture of H. pylori. Culture medium containing horse serum is convenient for allocation and storage and is worthy to be widespread use.%背景:全球50%以上的人口感染幽门螺杆菌(H.pylori),对其培养方法的研究非常重要.目的:研究不同培养基对H.pylori生长的影响.方法:制备固体和液体培养基,并加入脱纤维绵羊血和3种动物血清(羊、马、牛)行H.pylori培养.以细菌形态、涂片镜检、快速尿素酶试验、PCR法和菌体浓度鉴定H.pylori.结果:添加脱纤维绵羊血和动物血清的固体和液体培养基均可成功培养出H.pylori,其中脱纤维绵羊血的固体培养基扩菌浓度最高,添加马血清的固体和液体培养基的H.pylori扩菌效果均较理想.结论:固体和液体培养基均可取得较为满意的H.pylori扩菌效果,其中添加马血清的培养基更易于分装和保存,值得推广.

  12. Optimized lower leg injury probability curves from postmortem human subject tests under axial impacts.

    Science.gov (United States)

    Yoganandan, Narayan; Arun, Mike W J; Pintar, Frank A; Szabo, Aniko

    2014-01-01

    Derive optimum injury probability curves to describe human tolerance of the lower leg using parametric survival analysis. The study reexamined lower leg postmortem human subjects (PMHS) data from a large group of specimens. Briefly, axial loading experiments were conducted by impacting the plantar surface of the foot. Both injury and noninjury tests were included in the testing process. They were identified by pre- and posttest radiographic images and detailed dissection following the impact test. Fractures included injuries to the calcaneus and distal tibia-fibula complex (including pylon), representing severities at the Abbreviated Injury Score (AIS) level 2+. For the statistical analysis, peak force was chosen as the main explanatory variable and the age was chosen as the covariable. Censoring statuses depended on experimental outcomes. Parameters from the parametric survival analysis were estimated using the maximum likelihood approach and the dfbetas statistic was used to identify overly influential samples. The best fit from the Weibull, log-normal, and log-logistic distributions was based on the Akaike information criterion. Plus and minus 95% confidence intervals were obtained for the optimum injury probability distribution. The relative sizes of the interval were determined at predetermined risk levels. Quality indices were described at each of the selected probability levels. The mean age, stature, and weight were 58.2±15.1 years, 1.74±0.08 m, and 74.9±13.8 kg, respectively. Excluding all overly influential tests resulted in the tightest confidence intervals. The Weibull distribution was the most optimum function compared to the other 2 distributions. A majority of quality indices were in the good category for this optimum distribution when results were extracted for 25-, 45- and 65-year-olds at 5, 25, and 50% risk levels age groups for lower leg fracture. For 25, 45, and 65 years, peak forces were 8.1, 6.5, and 5.1 kN at 5% risk; 9.6, 7.7, and 6.1 k

  13. A Study of Models of Life Quality Development of Isan Marginal Communities as Affected by Installation of the Solar Home System

    Directory of Open Access Journals (Sweden)

    Pongsil Simvised

    2008-01-01

    Full Text Available Problem Statement: The electricity production system by using solar home cells is regarded as a substitute for energy which the state provides for the marginal communities because the area cannot be extended for putting up pylons with electric cables, all this for the marginal communities to have better life and being. The purposes of this thesis were to examine the history and development of the electricity production system by using solar home cells, and to examine models of life quality of Isan marginal communities as affected by the use of solar home system by using solar home cells. Approach: The sample consisted of 100 people in Isan marginal communities who lived in mountains, on highlands, on lowlands, and in national park areas with totally 4 areas. The instruments used for collecting data were an observation form, an interview form a group discourse note-taking form and workshop note-taking form. The 6 aspects of Minimum Needs (MN was included into every instrument. The data analysis results were subsequently presented by means of a descriptive analysis: Results: 1for the history and development of the solar home system, it was found that Thailand began using solar cells in 1977 by the Unit of Volunteer Doctors. At present, solar cells are used in various types: battery charging stations, communication systems, water pumping system, traffic light signals, blinkers and electric systems in marginal communities in general.2 for the models of life quality development of Isan marginal communities as affected by the use of the solar home system, the life quality was developed according to indicators of maximum needs in these 6 aspects: the model of developing good health, the model of developing progressive incomes, the models of This value cultivation and the model of developing cooperative development. It was found that the positive effects were at 98.67% and negative effects were at only 1.33%. Conclusion/Recommendation: There for, it can

  14. Understanding Biogeochemical and Hydrological Processes in a Reservoir, Kentucky Lake (USA), Using Long-term Monitoring and Real-time Sensors

    Science.gov (United States)

    Hendricks, S. P.; White, D.; Williamson, M.; Hooks, R.

    2010-12-01

    Kentucky Lake (USA), impounded in 1942, is the largest man-made reservoir east of the Mississippi River and one of more than 40 TVA impoundments in the Tennessee River system. The reservoir is 260 km long and 1.6 km wide with a water retention time of 23 days under normal water management conditions. The Hancock Biological Station and Center for Reservoir Research began a long-term monitoring program on Kentucky Lake in 1988. Fourteen to 17 sites are sampled every 16 days (32 in winter) for a variety of physicochemical and biological parameters. Two subwatershed streams, one agricultural and one forested, are sampled every 32 days. Nearly 450 monitoring cruises have been completed to date. The data have been valuable in understanding annual and long-term chemical and biological patterns; however, many short-term events are missed. To address this problem, a real-time (15-min sampling interval) monitoring station was established at a mid-lake navigation pylon in 2005. The combination of long-term and real-time monitoring has already provided a wealth of information on the reservoir resulting in a number of publications. Real-time data are openly available on the Station’s website at www.murraystate.edu/hbs. These and other data are being used in worldwide collaborations through the NSF supported Global Lake Ecological Observatory Network (GLEON). An NSF R2 collaboration (VOEIS) between Kentucky (Kentucky Lake) and Montana (Flathead Lake) is allowing us to expand the number of real-time sites using deployable buoys and optical sensors. Parameters being measured at 15 min intervals include water temperature, pH, dissolved oxygen, chlorophyll a, phycocyanin, specific conductance, oxidation-reduction potential, turbidity, and CDOM. Accompanying metstations on each buoy measure air temperature, barometric pressure, rainfall, wind speed, and PAR. One new buoy is being placed in the agricultural watershed embayment and a second in the forested watershed embayment

  15. The social impact of the snowfall of 8 March 2010 in Catalonia

    Science.gov (United States)

    Amaro, J.; Llasat, M. C.; Aran, M.

    2010-09-01

    The snowfall of 8 March 2010 affected almost all Catalonia, but especially the northeast where snow thickness was between 20 and 30 cm, locally with higher values up to 60 cm. Strong winds followed the event, exceeding 90 km/h in some places. As a result, infrastructures and public services, also private properties were damaged. Thousands of people were left stranded by the circulatory collapse, suspensions of railway service and by falling branches or trees on road infrastructures blocking accesses to residential areas. The regional government approved funds of 21.4 millions of Euros to mitigate the damage caused by this event, mainly invested in forest cleanup operations and in repairing road damage. The social impact of this event has been so high that 210 news have been published in a newspaper until 23 April, 190 of them during the month of March. From the study of the characteristics of this episode it can be stated that in the coast and pre-costal area, temperature at the same moment of precipitation was between 0ºC and 2ºC and humidity was high. In these zones, the type of precipitation was wet snow. It has to be considered that the combination of wet snow and wind can be a risk because of the ice-weight accumulated on objects (trees, electricity pylons...). As a consequence important damage happened in power network with significant collateral effects and more than 450,000 customers were affected by a power outage during some days. In this study we will compare the consequences of this event with others by means of information published in press. As a result, some set of consequences that are repeated regardless of the magnitude of the phenomenon will be identified. Finally, this event is also an example of the incision of social networks. This snowfall has been classified by mass media as the first "snowfall 2.0": 81600 entrances in Google, 132 Facebook groups and 750 videos made by amateurs in internet. From this study, we will present some reflexions

  16. A new DOAS instrument on long-distance IAGOS-CARIBIC flights and airborne DOAS applications

    Science.gov (United States)

    Penth, Lara; Frieß, Udo; Pöhler, Denis; Platt, Ulrich; Zahn, Andreas

    2017-04-01

    Within the IAGOS-CARIBIC project airborne DOAS (Differential Optical Absorption Spectroscopy) measurements of atmospheric trace gases are performed aboard a commercial long range passenger aircraft from Lufthansa since 2005. They provide a unique dataset for episodic, long-term and seasonal observations. The DOAS instrument is the only remote sensing technique aboard. DOAS is a well-established remote sensing technique to retrieve trace gas columns in the atmosphere from scattered light spectra of the sun. A series of trace gas species can be observed simultaneously, including nitrogen dioxide (NO2), sulphur dioxide (SO2), bromine oxide (BrO), nitrous acid (HONO), formaldehyde (HCHO) and ozone (O3). Since DOAS is a contact-free measurement technique, it is specially well suited for measuring highly reactive trace gases. It is widely used on different platforms and the airborne DOAS measurements are filling the gap between ground-based measurements and satellite data. The CARIBIC DOAS instrument is divided into an instrument unit within the CARIBIC container in the cargo hold of the aircraft, a telescope unit, which is specially designed for the permanently mounted pylon underneath the aircraft, and fiber optics in between. The instrument unit consists of three temperature stabilized spectrometers and the readout and control electronics. The telescope unit contains three telescopes, which observe scattered sunlight to the right under the elevation angles of +10˚ , -10˚ and -82˚ (nadir) relative to the horizon. This measurement geometry allows the separation of boundary layer, free tropospheric and stratospheric trace gas columns along the flight track. A new DOAS instrument was designed and installed in 2016 (first flights expected from March 2017) to improve the detection limits of NO2, SO2, BrO, HCHO, HONO, O3 and O4. Furthermore, an extended wavelength range allows to measure in addition iodine monoxide (a potentially important oxidant in the free troposphere

  17. cagA and vacA genotype of Helicobacter pylori associated with gastric diseases in Xi'an area

    Institute of Scientific and Technical Information of China (English)

    Wen Qiao; Jia-Lu Hu; Bing Xiao; Kai-Chun Wu; Dao-Rong Peng; John C Atherton; Hui Xue

    2003-01-01

    AIM: To establish stock of clinical Helicobacter pylori (H.pylon) isolates, to perform cagA and vacA typing of these isolates, to evaluate the relationship between genotypes of cagA and vacA and upper gastrointestinal diseases and to assess the association of vacA genotypes with presence of the pathogenicity marker-cagA.METHODS: Clinical H.pylori strains were isolated from the antrum of 259 patients in Clumbia agar. The isolated H.pylori strains were identified by histology, and16SrRNA PCR.CagA genotypes were detected by colony hybridization, the probe was derived from the cloned plasmid PcagA, and digested by EcoRI-HindⅢ and the isolated PcagA DNA fragment was radioactively labelled by the random priming method. vacA genes types (s,m)and subtypes (s1a, s1b,s2) were typed by PCR. Vacuolating toxin was detected with neutral red absorb test. The results were treated statistically by χ2test, ttest, and rank sum test.RESULTS: A total of 192 clinical H. pylori strains were isolated and the stock of Helicobacter pylori was established. The total positive rate of cagA was 87 % in all gastric diseases,and 95 % in gastric cancer group. There was a difference between gastric cancer group and the other groups (P<0.05)except duodenal ulcer group. The expression of type s1 of vacA was more than type s2 (P<0.05), and, the expression of type m1 was equal to type m2. In gastric cancer group,there was a difference between s1a and s1b (P<0.05), and s1a was more than s1b. Vacuolating toxins were more in Xi′an area isolates.CONCLUSION: The cagA+ vacA type s1 clinical isolates are more in Xi′an area, but this can not serve as an index to predict gastric cancer.

  18. 钢锚梁式钢-混组合索塔锚固体系设计与分析%Design and Analysis of Steel-concrete Composite Anchorage Structure with Steel Anchor Beam

    Institute of Scientific and Technical Information of China (English)

    苗通; 孙蕊鑫

    2015-01-01

    A bridge is a twin towers and double cable plane prestressed concrete girder cable -stayed bridge with a span arrangement of (130 +300 +130)m,and the tower type is inverted Y and the Steel -concrete Composite anchorage structure with Steel Anchor Beam is used to anchorage the cable of end of the tower.Among this type anchorage system,the anchor boxes have been welded on both sides of the steel anchor beam,at the same time, using steel bracket to replace traditional concrete corbel structure.In this paper,the characteristics of this kind of anchor system has been introduced and the stress situation of this kind of anchor system has been analyzed u-sing the finite element method.The research conclusion can provide a reference for the design of this type of ca-ble pylon anchorage system.%某斜拉桥主桥是一座跨径布置为(130m +300m +130m)的双塔双索面预应力混凝土梁斜拉桥,索塔采用倒 Y 型,斜拉索在桥塔端采用新型空间索面钢锚梁式钢-混组合索塔锚固体系进行锚固。该型锚固体系将锚箱焊在钢锚梁两侧,同时采用钢牛腿替换传统的混凝土牛腿结构,提高了施工速度,改善了结构受力。介绍了该种锚固体系的特点,并采用有限元方法对改型索塔锚固体系的受力情况进行了分析,可为该类型索塔锚固体系设计提供参考。

  19. The aeromechanical stability of soft-inplane tiltrotors

    Science.gov (United States)

    Howard, Anna Kathleen Tyler

    A soft-inplane tiltrotor can be subject to the aeromechanical instabilities of ground and air resonance in addition to whirl flutter. While whirl flutter has been studied by many researchers, air and ground resonance in a tiltrotor has not been explored thoroughly. This dissertation investigates the aeromechanical instabilities of air and ground resonance in a tiltrotor and to assess some passive methods for improving the stability of a soft-inplane tiltrotor. This research is broken into two parts, addressing the semi-span model and the full-span model. In the first chapters, a semi-span analytical model consisting of a rigid blade rotor coupled to a rigid pylon and an elastic wing is developed and validated. The Boeing Model 222 which was wind-tunnel tested in 1972 is used to validate the current analytical model. This aircraft is used as the baseline for the analytical investigation of ground resonance and air resonance in hover, air resonance in transition, and air resonance and whirl flutter in airplane configuration. Neither ground resonance nor air resonance in hover are predicted for the Model 222 though air resonance in transition and cruise as well as whirl flutter at high speeds are predicted. Aeroelastic couplings in the rotor blades and wing are shown to affect the air resonance stability in cruise and transition and to be useful in augmenting the inherent stability of the aircraft. Wing vertical bending coupled to wing torsion and rotor low frequency lag coupled to blade torsion were helpful for air resonance. However, the rotor coupling was quite detrimental to whirl flutter stability and the wing coupling was unable to stabilize all the air resonance regions completely. The second part of the thesis expands the semi-span model to full-span: fuselage pitch and roll motion, anti-symmetric wing motion, and the second rotor motion are added. The full-span model determined that fuselage motion can couple with rotor low frequency lag to exhibit air

  20. 机体/动力装置一体化分析中的动力影响效应数值模拟%Numerical simulation method for the powered effects in airframe/propulsion integration analysis

    Institute of Scientific and Technical Information of China (English)

    谭兆光; 陈迎春; 李杰; 张淼

    2009-01-01

    采用合适的进、排气边界条件,对带动力的单独涡扇发动机模型和带动力的DLR-F6翼身架舱复杂组合体(WBPN)模型的流场进行了数值模拟和分析.运用Roe三阶迎风偏置通量差分裂方法和隐式近似因子分解方法求解雷诺平均Navier-Stokes方程,基于点搭接多块网格技术生成高质量计算网格,通过多重网格技术来加速收敛.着重对动力发动机进、排气边界条件的给定进行了推导,以准确地模拟发动机动力效应.计算结果与实验值吻合良好,验证了所采用计算方法、网格分块策略和边界条件处理方法的正确性.%The flow-fields around powered isolated turbofan engine model and powered DLR-F6 wing/body/pylon/nacelle (WBPN) model were numerically simulated and analyzed by the appropriate fan inlet face and jet-exit boundary conditions.Three-dimensional time-dependent compressible Reynolds-averaged Navier-Stokes equations were solved with third-order upwind-biased flux-difference splitting method and approximate factorization method.The point-to-point patched multi-block technology was used to generate high quality grid.The multi-grid technique was employed to accelerate the convergence.For a better simulation of the powered effects,the fan inlet face boundary conditions and jet-exit boundary conditions were determined.Computational results and comparisons with experimental data were presented.The good agreement indicates that the numerical method,grid blocking strategy and management of boundary conditions are validated.

  1. 高效气动优化设计方法%Efficient Aerodynamic Design Optimization of Complex Configuration

    Institute of Scientific and Technical Information of China (English)

    傅林; 左英桃

    2012-01-01

    基于CFD方法开展气动外形优化设计通常计算量较大,采用离散共轭方法计算目标函数梯度,建立了高效的飞机气动优化设计系统.采用NURBS方法对翼剖面几何外形的扰动量进行参数化,避免了对原始外形的拟合,建立了基于NURBS方法的机翼剖面参数化方法.在复杂外形的优化设计中,动网格方法是关键技术之一,采用无限插值方法生成变形后的网格,并提出采用无限插值方法处理部件之间相贯线发生变化的情况.最后开展了翼身组合体+吊舱+挂架等复杂外形的优化设计,成功地减小了阻力,证明了方法的有效性.%Large scales of computations are required in aerodynamic optimization based on CFD methodologies.Efficient aerodynamic design optimization system is built in this paper,and the gradients of object functions are calculated with discrete adjoint method.The geometric perturbations of wing sections are parameterized with NURBS method,furthermore parameterization methodology of wing based on NURBS are built.Moving grid is one of key technologies in aerodynamic optimization design of very complex configuration.Transfinite interpolation methodology is utilized to generate new grid, and a methodology based on transfinite interpolation technology is proposed to deal with the surface grid in the case of junction lines varying.Configurations including wing - body - nacelle - pylon are optimized with the design optimization system.The drag is reduced successfully, which illustrates the effectiveness of the methodology built in this paper.

  2. Higher-order spectra for identification of nonlinear modal coupling

    Science.gov (United States)

    Hickey, Daryl; Worden, Keith; Platten, Michael F.; Wright, Jan R.; Cooper, Jonathan E.

    2009-05-01

    symmetry and has been shown to work well in this limited case. The current paper will consider a model of a continuous wing-pylon model with reduced symmetry in order to assess the utility of the method in a more general situation, the analysis is also extended to assess the utility of the trispectrum.

  3. Aeroelastic response and stability of tiltrotors with elastically-coupled composite rotor blades. Ph.D. Thesis

    Science.gov (United States)

    Nixon, Mark W.

    1993-01-01

    There is a potential for improving the performance and aeroelastic stability of tiltrotors through the use of elastically-coupled composite rotor blades. To study the characteristics of tiltrotors with these types of rotor blades it is necessary to formulate a new analysis which has the capabilities of modeling both a tiltrotor configuration and an anisotropic rotor blade. Background for these formulations is established in two preliminary investigations. In the first, the influence of several system design parameters on tiltrotor aeroelastic stability is examined for the high-speed axial flight mode using a newly-developed rigid-blade analysis with an elastic wing finite element model. The second preliminary investigation addresses the accuracy of using a one-dimensional beam analysis to predict frequencies of elastically-coupled highly-twisted rotor blades. Important aspects of the new aeroelastic formulations are the inclusion of a large steady pylon angle which controls tilt of the rotor system with respect to the airflow, the inclusion of elastic pitch-lag coupling terms related to rotor precone, the inclusion of hub-related degrees of freedom which enable modeling of a gimballed rotor system and engine drive-train dynamics, and additional elastic coupling terms which enable modeling of the anisotropic features for both the rotor blades and the tiltrotor wing. Accuracy of the new tiltrotor analysis is demonstrated by a comparison of the results produced for a baseline case with analytical and experimental results reported in the open literature. Two investigations of elastically tailored blades on a baseline tiltrotor are then conducted. One investigation shows that elastic bending-twist coupling of the rotor blade is a very effective means for increasing the flutter velocity of a tiltrotor, and the magnitude of coupling required does not have an adverse effect on performance or blade loads. The second investigation shows that passive blade twist control via

  4. Multi-Body Analysis of the 1/5 Scale Wind Tunnel Model of the V-22 Tiltrotor

    Science.gov (United States)

    Ghiringhelli, G. L.; Masarati, P.; Mantegazza, P.; Nixon, M. W.

    1999-01-01

    The paper presents a multi-body analysis of the 1/5 scale wind tunnel model of the V-22 tiltrotor, the Wing and Rotor Aeroelastic Testing System (WRATS), currently tested at NASA Langley Research Center. An original multi-body formulation has been developed at the Dipartimento di Ingegneria Aerospaziale of the Politecnico di Milano, Italy. It is based on the direct writing of the equilibrium equations of independent rigid bodies, connected by kinematic constraints that result in the addition of algebraic constraint equations, and by dynamic constraints, that directly contribute to the equilibrium equations. The formulation has been extended to the simultaneous solution of interdisciplinary problems by modeling electric and hydraulic networks, for aeroservoelastic problems. The code has been tailored to the modeling of rotorcrafts while preserving a complete generality. A family of aerodynamic elements has been introduced to model high aspect aerodynamic surfaces, based on the strip theory, with quasi-steady aerodynamic coefficients, compressibility, post-stall interpolation of experimental data, dynamic stall modeling, and radial flow drag. Different models for the induced velocity of the rotor can be used, from uniform velocity to dynamic in flow. A complete dynamic and aeroelastic analysis of the model of the V-22 tiltrotor has been performed, to assess the validity of the formulation and to exploit the unique features of multi-body analysis with respect to conventional comprehensive rotorcraft codes; These are the ability to model the exact kinematics of mechanical systems, and the possibility to simulate unusual maneuvers and unusual flight conditions, that are particular to the tiltrotor, e.g. the conversion maneuver. A complete modal validation of the analytical model has been performed, to assess the ability to reproduce the correct dynamics of the system with a relatively coarse beam model of the semispan wing, pylon and rotor. Particular care has been used

  5. Advanced Computational and Experimental Techniques for Nacelle Liner Performance Evaluation

    Science.gov (United States)

    Gerhold, Carl H.; Jones, Michael G.; Brown, Martha C.; Nark, Douglas

    2009-01-01

    The Curved Duct Test Rig (CDTR) has been developed to investigate sound propagation through a duct of size comparable to the aft bypass duct of typical aircraft engines. The axial dimension of the bypass duct is often curved and this geometric characteristic is captured in the CDTR. The semiannular bypass duct is simulated by a rectangular test section in which the height corresponds to the circumferential dimension and the width corresponds to the radial dimension. The liner samples are perforate over honeycomb core and are installed on the side walls of the test section. The top and bottom surfaces of the test section are acoustically rigid to simulate a hard wall bifurcation or pylon. A unique feature of the CDTR is the control system that generates sound incident on the liner test section in specific modes. Uniform air flow, at ambient temperature and flow speed Mach 0.275, is introduced through the duct. Experiments to investigate configuration effects such as curvature along the flow path on the acoustic performance of a sample liner are performed in the CDTR and reported in this paper. Combinations of treated and acoustically rigid side walls are investigated. The scattering of modes of the incident wave, both by the curvature and by the asymmetry of wall treatment, is demonstrated in the experimental results. The effect that mode scattering has on total acoustic effectiveness of the liner treatment is also shown. Comparisons of measured liner attenuation with numerical results predicted by an analytic model based on the parabolic approximation to the convected Helmholtz equation are reported. The spectra of attenuation produced by the analytic model are similar to experimental results for both walls treated, straight and curved flow path, with plane wave and higher order modes incident. The numerical model is used to define the optimized resistance and reactance of a liner that significantly improves liner attenuation in the frequency range 1900-2400 Hz. A

  6. Optimization of composite tiltrotor wings with extensions and winglets

    Science.gov (United States)

    Kambampati, Sandilya

    Tiltrotors suffer from an aeroelastic instability during forward flight called whirl flutter. Whirl flutter is caused by the whirling motion of the rotor, characterized by highly coupled wing-rotor-pylon modes of vibration. Whirl flutter is a major obstacle for tiltrotors in achieving high-speed flight. The conventional approach to assure adequate whirl flutter stability margins for tiltrotors is to design the wings with high torsional stiffness, typically using 23% thickness-to-chord ratio wings. However, the large aerodynamic drag associated with these high thickness-to-chord ratio wings decreases aerodynamic efficiency and increases fuel consumption. Wingtip devices such as wing extensions and winglets have the potential to increase the whirl flutter characteristics and the aerodynamic efficiency of a tiltrotor. However, wing-tip devices can add more weight to the aircraft. In this study, multi-objective parametric and optimization methodologies for tiltrotor aircraft with wing extensions and winglets are investigated. The objectives are to maximize aircraft aerodynamic efficiency while minimizing weight penalty due to extensions and winglets, subject to whirl flutter constraints. An aeroelastic model that predicts the whirl flutter speed and a wing structural model that computes strength and weight of a composite wing are developed. An existing aerodynamic model (that predicts the aerodynamic efficiency) is merged with the developed structural and aeroelastic models for the purpose of conducting parametric and optimization studies. The variables of interest are the wing thickness and structural properties, and extension and winglet planform variables. The Bell XV-15 tiltrotor aircraft the chosen as the parent aircraft for this study. Parametric studies reveal that a wing extension of span 25% of the inboard wing increases the whirl flutter speed by 10% and also increases the aircraft aerodynamic efficiency by 8%. Structurally tapering the wing of a tiltrotor

  7. The geomorphic impact of catastrophic glacier ice loss in mountain regions

    Science.gov (United States)

    Evans, S. G.

    2006-12-01

    Perhaps the most dramatic manifestation of global warming is catastrophic glacier ice loss in mountain regions. The geomorphic impact of this process was first outlined by Evans and Clague in 1994 and includes mountain slope instability, glacier avalanching, the formation and failure of moraine dammed lakes, and the formation and failure of ice dammed lakes. The present paper is an update of the 1994 publication and has three components. First, a global review of recent glacier-related geomorphic events is undertaken. Second, an analysis of two cases from the Coast Mountains of British Columbia - the 1975 Devastation Glacier landslide and the 1983 Nostetuko Lake outburst resulting from the failure of a moraine dam illustrates the interaction of glacier ice loss and related geomorphic events. At Devastation Glacier, approximately 13 M m3 of altered Quaternary volcanic rock and glacier ice was lost from the west flank of Pylon Peak in the Mount Meager volcanic complex. The events were initiated by a catastrophic rockslide, involving altered Quaternary pyroclastic rocks, which continued down Devastation Creek valley as a high velocity debris avalanche. The overall length of the slide path was 7 km and the vertical height of the path was 1220 m yielding a fahrboschung of 10°. Other large landslides occurred in Devastation Creek valley in 1931 and 1947. Stability analysis of the initial failure shows that the 1975 rockslide was the result of a complex history of glacial erosion, loading and unloading of the toe of the slide mass caused by the Little Ice Age advance and subsequent retreat of Devastation Glacier. The shearing resistance along the base of the rockslide mass was reduced prior to 1975 by substantial previous slope displacements related to glacial ice loss. Some of this displacement is likely to have occurred as subglacial slope deformation since ice fall and crevasse patterns suggest the presence of slide like shearing displacements below the base of

  8. 2007 Research and Engineering Annual Report

    Science.gov (United States)

    Stoliker, Patrick; Bowers, Albion; Cruciani, Everlyn

    2008-01-01

    Selected research and technology activities at NASA Dryden Flight Research Center are summarized. These following activities exemplify the Center's varied and productive research efforts: Developing a Requirements Development Guide for an Automatic Ground Collision Avoidance System; Digital Terrain Data Compression and Rendering for Automatic Ground Collision Avoidance Systems; Nonlinear Flutter/Limit Cycle Oscillations Prediction Tool; Nonlinear System Identification Using Orthonormal Bases: Application to Aeroelastic/Aeroservoelastic Systems; Critical Aerodynamic Flow Feature Indicators: Towards Application with the Aerostructures Test Wing; Multidisciplinary Design, Analysis, and Optimization Tool Development Using a Genetic Algorithm; Structural Model Tuning Capability in an Object-Oriented Multidisciplinary Design, Analysis, and Optimization Tool; Extension of Ko Straight-Beam Displacement Theory to the Deformed Shape Predictions of Curved Structures; F-15B with Phoenix Missile and Pylon Assembly--Drag Force Estimation; Mass Property Testing of Phoenix Missile Hypersonic Testbed Hardware; ARMD Hypersonics Project Materials and Structures: Testing of Scramjet Thermal Protection System Concepts; High-Temperature Modal Survey of the Ruddervator Subcomponent Test Article; ARMD Hypersonics Project Materials and Structures: C/SiC Ruddervator Subcomponent Test and Analysis Task; Ground Vibration Testing and Model Correlation of the Phoenix Missile Hypersonic Testbed; Phoenix Missile Hypersonic Testbed: Performance Design and Analysis; Crew Exploration Vehicle Launch Abort System-Pad Abort-1 (PA-1) Flight Test; Testing the Orion (Crew Exploration Vehicle) Launch Abort System-Ascent Abort-1 (AA-1) Flight Test; SOFIA Flight-Test Flutter Prediction Methodology; SOFIA Closed-Door Aerodynamic Analyses; SOFIA Handling Qualities Evaluation for Closed-Door Operations; C-17 Support of IRAC Engine Model Development; Current Capabilities and Future Upgrade Plans of the C-17 Data

  9. Ringing of White Storks Ciconia ciconia in NE Slovenia during the 1984–2013 period

    Directory of Open Access Journals (Sweden)

    Bračko Franc

    2016-12-01

    Full Text Available In a period of 30 years (1984-2013, 1,535 White Stork pulli were ringed on nest and 1,226 nests examined in NE Slovenia. The ringing was implemented in the regions of Dravsko polje, Slovenske gorice and Pomurje. In each season, from 9 to 85 nests were examined, the great majority of them built on overhead powerline pylons. On average, 51.16 pulli or 16.66% were ringed and 40.86 or 18.91% nests visited compared to the census of fledged pulli and inventoried nests in 1999 in NE Slovenia. A total of 71 finds or 4.6% were registered and 37 rings or 52% finds read. There were 26 (36.62% local recoveries, while in foreign countries 34 (47.88% recoveries of Slovenian-ringed storks were made. Two of our recoveries were registered abroad prior to 1984. There were 11 (15.49% foreign recoveries. Local recoveries (n = 26 indicate breeding relationship (mixing between the eastern and southern Slovenian breeding populations. The longest distance of breeding was 115 km in a beeline, the shortest 62 km (n = 4. Other 12 local recoveries at 1 to 38 km from the place of hatching concerns the native NE breeding area. Young sexually mature storks search for new breeding sites only in their fourth year of age. No ringed stork returned to the native nest as a young breeder. The oldest was 14 years old. Some of them breed in the wider area of the Pannonian Plain outside Slovenia, e.g. 3 in Austria, 2 in Serbia and 1 in Croatia. One of them bred in Slovakia 463 km away. In view of the presented recoveries it has been ascertained that the storks from NE Slovenia migrate across the Pannonian Plain, the Balkans and Asia Minor, down to the South African Republic of 8,923 km in a beeline (4 recoveries, using the eastern migration route. The western migration route was not ascertained. The majority of recoveries originated from the autumn migration period, with only one recovery known from the spring migration period. No less than 23 ringed storks, particularly young ones

  10. Diffusive Soil Degassing of Radon and Carbon Dioxide at San Miguel Volcano, El Salvador, Central America

    Science.gov (United States)

    Lopez, D. L.; Olmos, R.; Cartagena, R.; Soriano, T.; Barahona, F.

    2001-12-01

    San Miguel volcano is located 15 km to the Southwest of San Miguel City (population ~300,000) and lies on the southern fault of the Central American graben at an intersection with NW-SE faults. The composition of San Miguel lavas varies from olivine-pyroxene basalts for the older lava flows to more andesitic compositions for the more recent products. This volcano have been degassing and having small ash emission since the late nineteen eighties. During December 1999 and January 2000, radon gas concentrations (pCi/l) in soils were measured using a Pylon AB5 radon monitor, and flux of CO2 (g/m2/day) was determined using the accumulation chamber method at 205 sampling stations. High gas emission inside the crater did not allow measurements to be taken in that region. CO2 fluxes throughout the soils of the volcanic edifice show low values compared to other active volcanoes of the world, suggesting that San Miguel is degassing preferentially throughout the summit region. CO2 fluxes range from less than 1 to 14 g/m2/day, with an average value of 5.6 g/m2/day. Radon concentrations range from 2 to 833 pCi/l with an average value of 110 pCi/l. Thoron concentrations range from 20 to 2178 pCi/l with an average value of 362 pCi/l. These values are comparable to radon concentrations found in other active volcanoes (e.g. Cerro Negro, Connor et al., 1996). CO2 flux, radon and thoron concentrations show higher values to the northwest and northeast faulted regions. Some anomalies seem to be related to the contact region between the older and more recent lava flows. Thoron/radon ratios show high anomalies aligning in the NW-SE direction where faulting also occurs. These results suggests that low permeability rocks forming the volcanic edifice of San Miguel volcano do not allow large fluxes of magmatic CO2 to be discharged throughout the soils. Higher permeability at faults and contacts allow slightly larger fluxes of CO2 and radon and thoron concentrations.

  11. The Effect of Deck Width Addition Toward Stability of Cable Stayed Bridge: Case Study of Siak Sri Indrapura Bridge, Riau

    Directory of Open Access Journals (Sweden)

    Supriyadi Bambang

    2017-01-01

    Full Text Available An aeroelastic interaction always take places in long-span bridge, i.e. the dynamic relationship between wind forces (aerodynamic and bridge structural motion (dynamics. Wind forces may lead to serviceability and safety problems, and may even cause instability of the whole bridge structure due to the flexibility nature of long span bridge structures.The slimer girder plate will make the structure more unstable as can be seen from the occurrence of lateral deformation. This paper presents the results analysis of cable stayed bridge that has total span of 640 m, two planes configuration of harp-typed hanger cable, the A shape pylons span along 320 m (main span,and side span of 160m. Structural analysis was conducted to determine the optimum ratio between width and spans of cable stayed bridge. The bridge was modeled with various width of 7 to 22 m. Structural modelling was conducted using SAP2000 software to analyze the structural stability of cable stayed bridge under wind load at speed of 35 m/s.The influence of wind loads to the cable stayed bridge stability can be seen based on the bridge deck deformation at the Y-axis (U2, in which for the width of the bridge deck of 7 m, 8 m, 9 m and 10 m, the deformation of U2 are 0.26 m; 0.17 m; 0.12 m and 0.10 m, respectively. Meanwhile, for bridge’s width of 11-22 m, the value of U2 axis deformation is relatively constant between 0.08 m to 0.07 m. This finding suggests that the ratio between width and length of bridge greatly affect the stability of the cable stayed bridge. Cable-stayed bridge, especially for concrete bridge, with two plain system having optimum ratio of width and length show no sign of an aerodynamic instability when fulfills the requirements of B ≥ L / 3.

  12. Analysis of the hazardous low-altitude snowfall, 8th March 2010, in Catalonia

    Science.gov (United States)

    Aran, M.; Rigo, T.; Bech, J.; Brucet, C.; Vilaclara, E.

    2010-09-01

    During winter season snow precipitation is quite frequent in the Pyrenees (north-east of the Iberian Peninsula). On average the total amount of fresh snow at 2200 metres is of 250 cm. However, important snow episodes at low latitudes are unlikely. From 1947 to 2009, 16 significant snow episodes took place in the Barcelona and 18 in Girona areas. On 8th March 2010, a severe wet snow event had a high social impact on these regions. One of the most remarkable features of this episode was the type of precipitation (wet snow) and the large amount of precipitation combined with strong wind gust that caused the collapse of electricity pylons and tree forests. The damage was very important in the north-eastern part and the regional government approved funds of 21.4 million € to reduce the impact caused by this event. Although diagnosis of other low altitude snowfall events in Catalonia has been done previously, the analysis of this event can contribute to characterise a little bit better these snow episodes. In this study, we will present the synoptic framework characterised by the presence of a deep low in the north-east of Catalonia and moving through Ebro valley to the Catalan coast. To do this we will use ECMWF reanalyses and Meteosat images. The main features to predict this snow event and the critical point were the total amount of precipitation and snow level forecasted by mesoscale models (MM5, WRF). The model outputs for precipitation, temperature and wind will be compared with automatic weather, radar and radiosounding data. The snow level and the type of precipitation are compared with the information received from spotters. The main storm was characterised by moderate vertical development with tops of 8 km (4 km were the average height during the initial and final phase of the event). Also, lightning activity was observed, 310 intra-cloud and 128 cloud-to-ground. The type of precipitation at a specific location in the eastern zone temporally changed because

  13. The prediction of noise and installation effects of high-subsonic dual-stream jets in flight

    Science.gov (United States)

    Saxena, Swati

    Both military and civil aircraft in service generate high levels of noise. One of the major contributors to this noise generated from the aircraft is the jet engine exhaust. This makes the study of jet noise and methods to reduce jet noise an active research area with the aim of designing quieter military and commercial aircraft. The current stringent aircraft noise regulations imposed by the Federal Aviation Administration (FAA) and other international agencies, have further raised the need to perform accurate jet noise calculations for more reliable estimation of the jet noise sources. The main aim of the present research is to perform jet noise simulations of single and dual-stream jets with engineering accuracy and assess forward flight effects on the jet noise. Installation effects such as caused by the pylon are also studied using a simplified pylon nozzle configuration. Due to advances in computational power, it has become possible to perform turbulent flow simulations of high speed jets, which leads to more accurate noise predictions. In the present research, a hybrid unsteady RANS-LES parallel multi-block structured grid solver called EAGLEJet is written to perform the nozzle flow calculations. The far-field noise calculation is performed using solutions to the Ffowcs Williams and Hawkings equation. The present calculations use meshes with 5 to 11 million grid points and require about three weeks of computing time with about 100 processors. A baseline single stream convergent nozzle and a dual-stream coaxial convergent nozzle are used for the flow and noise analysis. Calculations for the convergent nozzle are performed at a high subsonic jet Mach number of Mj = 0.9, which is similar to the operating conditions for commercial aircraft engines. A parallel flow gives the flight effect, which is simulated with a co-flow Mach number, Mcf varying from 0.0 to 0.28. The grid resolution effects, statistical properties of the turbulence and the heated jet effects

  14. 复杂几何细节对增升装置气动性能影响研究%Study on Influence of Complex Geometry Details on the Aerodynamic Performance of High-lift System

    Institute of Scientific and Technical Information of China (English)

    邱亚松; 白俊强; 李亚林; 周涛

    2012-01-01

    By numerical simulation, the influence of the main-wing root geometry details, wing-mounted engine nacelle, slat tracks and flap track fairings on the aerodynamic performance of a high-lift system is investigated. The results show that a separated low-power vortex is generated by the wing-root fairing which is left at the main-wing root when the slat is cut, and the aerodynamic performance of the lift system is damaged seriously by this vortex. Cutting most of the wing-root fairing as part of the slat can eliminate the condition needed to generate the separated low-power vortex. Remarkable decrease of the stall angle and maxim lift coefficient is caused by a large size wing-mounted engine nacelle. This is mainly because of the flow mechanism that a large space filled with low-speed fluid above the upper surface of the main wing is generated by the separated fluid which comes from the nacelle upper surface, pylon and the gaps between the pylon and slat. Strong vortices generated by the nacelle strake with proper shape and setting at proper positions can eliminate most of the low-speed fluid and recover part of the aerodynamic performance loss. Low-momentum wake flow generated by the slat tracks mixed with the boundary layer of the main wing causes the loss of the lift. Large fluid separation may be caused by the slat track at high angles of attack, which will result in a remarkable loss of the aerodynamic performance. The flap slot section area may be diminished as a result of the blockage effect of the large size geometry the of flap track fairings, which may cause the high speed flow of the flap slot to move faster, thus blowing away the separation flow on the flap surface.%采用数值模拟的方法研究了主翼翼根几何形状、翼吊发动机短舱、缝翼滑轨及襟翼滑轨舱等几何细节对增升装置气动性能的影响.研究结果表明:切割前缘缝翼时,将大部分翼根整流包留在主翼上会在大迎角下产生低能量的分离

  15. Influence of dynamic excitation on the bearing capacity of reinforced concrete columns exposedto fire effects Влияние динамического эффекта на несущую способность железобетонных колонн, работающих в условиях огневых воздействий

    Directory of Open Access Journals (Sweden)

    Avetisyan Levon Avetisovich

    2013-09-01

    Full Text Available This article provides an example of the calculation of eccentrically compressed reinforced concrete elements exposed to dynamic loads and fire effects. The dynamic factor for the concrete under regular conditions is available, and it exceeds one in any case. However, in case of a fire exposure, the value of this factor varies from 0,4 to 0,8, depending on the loading rate and temperature. The value of the dynamic factor was identified in the course of an experiment; thereafter, the pattern of influence of the dynamic effect caused by the progressive collapse of buildings and produced onto the bearing capacity and fire resistance of compressed elements of the pylon and the column was identified. ANSYS 12.1 software package was employed to perform the fire resistance analysis of the pylon on the 1st floor of a 59-storey building. The problem was modeled in the 3D formulation. It represented a pylon exposed to static loading and standard fire conditions. For comparison purposes, bearing capacity values were calculated for different values of the thermal load.The calculation of temperature fields was based on the resolution of boundary value problems of transient heat conduction in capillary-porous bodies.The solution to the problem of the four-sided fire exposure at standard fire temperature values was obtained in characteristic points of the support structure to assess the change in its load-bearing capacity.It is proven that dynamic effects of a fire reduce the bearing capacity of columns by 40 %. Therefore, the analysis of the bearing capacity of structures in terms of their fire resistance should take account of the possibility of progressive collapse of buildings.Приведен пример расчета внецентренно сжатых железобетонных элементов, работающих в условиях динамических нагрузок и огневых воздействий. Коэффициенты д

  16. 黄冈公铁两用长江大桥主墩基础围堰施工技术%Construction Techniques of Cofferdams for Main Pier Foundations of Huanggang Changjiang River Rail-cum-Road Bridge

    Institute of Scientific and Technical Information of China (English)

    金红岩

    2012-01-01

    The main bridge of Huanggang Changjiang River Rail-cum-Road Bridge is a steel truvss girder cable-stayed bridge with double pylons and double cable planes and the foundations for the main piers of the bridge were constructed by the double-wall steel boxed cofferdams. The cofferdams were integrally manufactured and assembled on bank and by means of survey, the o-verall dimensions, pile locations and the locations and concentricity of the upper and lower guiding rings of the cofferdams were controlled in order to ensure that the deviations of the bored piles and pile caps of the main piers could comply with the relevant requirements in the standards after construction and to obtain the accuracy of positioning of the cofferdams according to the results of comprehensive analysis of the survey. The cofferdams were launched to the river by air bags by way of gradually adjusting the launching gradient from 1:30 to 1: 5 so as to ensure the launching speed and sliding distances of the cofferdams. After the cofferdams were launched to the river, they were floated to the pier sites, tugged by the strong house power tug boats and were positioned by the gravity anchors plus positioning barges in three stages of initially positioning, accurately positioning and system transformation. The final accuracy of positioning of the cofferdams in plan is 5 cm, the perpendicularity is within 1/1 000 and the perpendicularity of the steel casings is within 1/500, which all meet the requirements in the standards.%黄冈公铁两用长江大桥主桥为双塔双索面钢桁梁斜拉桥,主墩基础采用双壁钢吊箱围堰法施工.钢吊箱围堰在岸上整体拼装制造,通过测量控制围堰的轮廓尺寸,桩位,上、下导环的位置与同心度等,确保基础施工后主墩钻孔桩及承台施工偏差符合标准要求,并根据实测结果综合分析得出钢围堰的定位精度;采用气囊法下水,将下水坡度从1∶30逐渐调整为1∶5,保证了

  17. Varioliform gastritis: comparative therapy between patients with and without eradication of Helicobacter pylori%根除幽门螺杆菌前后对痘疹样胃炎治疗效果的比较

    Institute of Scientific and Technical Information of China (English)

    张彦敏; 姜葵; 王邦茂; 章明放; 王锐

    2011-01-01

    目的:评价痘疹样胃炎根除幽门螺杆菌(H.pylori)后的治疗效果以及病理变化情况,明确根除H.pylori对痘疹样胃炎的治疗意义.方法:325例痘疹样胃炎患者根据H.pylori检测结果分为阳性组(标准三联或四联疗法)与阴性组(单纯抑酸),比较治疗效果;阳性组根据复查胃镜H.pylori的结果再分为两组,比较病理情况的改善.结果:H.pylori阳性组总有效率(73.68%)与H.pylori阴性组总有效率(72.50%)差异无统计学意义(P>0.05);H.pylori根除后痘疹样胃炎治疗总有效率优于未根除者,差异有统计学意义(89.02% vs 37.84%,P<0.05);根除H.pylori与否对萎缩性炎症、肠化生、不典型增生的病理改善情况差异有统计学意义(均P<0.05).结论:根除H.pylori对痘疹样胃炎的治疗有显著意义,且能部分逆转肠化生、不典型增生等病理改变.%AIM: To compare the efficacy of therapy of varioliform gastritis between patients with and without eradication of Helicobacter pylori (H.pylon).METHODS: Three hundred and twenty-five patients with varioliform gastritis were divided into two groups: patients with and without H.pylori infection. Patients with H.pylori infection were treated by standard triple or quadruple therapy and simultaneously with H2-recetor blockers or proton pump inhibitors, while those without H.pylori infection were treated simply with H2-recetor blockers or proton pump inhibitors. Treatment efficacy and pathological alterations were compared between patients received H. pylori therapy and those who did not as well as between H.pylori-infected patients with and without eradication of H.pylori.RESULTS: There was no significant difference in the total response rate between patients with and without H.pylori infection (73.68% vs 72.50%,P > 0.05). The total response rate was significantly higher in H. pylori-infected patients with H.pylori eradication than those without H.pylori eradication (89.02% vs 37.84%, P < 0

  18. Overall Design and Study of South and North Bridges of Xiazhang Sea-Crossing Bridge%厦漳跨海大桥南、北汊桥总体设计与研究

    Institute of Scientific and Technical Information of China (English)

    王福敏; 罗强; 李军

    2013-01-01

    厦漳跨海大桥主要由北汊桥、海门岛立交及收费服务区、南汊桥、海平立交四大部分组成,全长9.333 km.为适应复杂的自然与建设条件,对该桥桥位方案进行比选,并对项目中关键控制性工程(北汊主桥、南汊主桥)的桥型方案进行研究.经研究,最终确定北汊主桥采用主跨780m的五跨连续钢箱梁斜拉桥方案,南汊主桥采用主跨300 m的结合梁斜拉桥方案.针对项目中复杂的地质条件、高地震烈度和恶劣的风环境,分别采取设置适应性强的桩基础,对较差的桩基地质注浆;按抗震要求进行构造设计,在主桥塔梁处设置纵向阻尼器,引桥设置减隔震支座;北汊主桥采用一种翼型扶手栏杆、南汊主桥采用分流板抗风等措施进行处理.%The Xiazhang Sea-Crossing Bridge,totally 9.333 km long,is composed of four major parts of the north bridge,Haimen Island interchange and toll service area,south bridge and Haiping interchange.To accommodate the complicated natural and construction conditions of the bridge,the bridge site schemes were compared and the bridge type schemes for the critical control projects (the north and south main bridges) were studied.According to the study,it was finally determined that the 5-span continuous steel box girder cable-stayed bridge with a main span 780 m would be adopted for the north main bridge and the composite girder cable-stayed bridge with a main span 300 m would be adopted for the south main bridge.In consideration of the complicated geologic conditions,high intensity earthquake and harsh wind environment,the well adaptive pile foundations were respectively utilized.For the pile foundations at the locations with poor geology,the foundations would be grouted.The structures of the bridge were designed in compliance with the seismic resistance requirements.At the connections between the pylons and girders of the main bridges,the longitudinal dampers were arranged and on the piers

  19. Control Technique for Accurate Landing of Caisson of Pier No.3 of Tongling Changjiang River Bridge on Hefei-Fuzhou Railway onto Riverbed%合福铁路铜陵长江大桥3号墩沉井精确着床控制技术

    Institute of Scientific and Technical Information of China (English)

    覃勇刚; 涂满明; 王东辉

    2013-01-01

    The main bridge of Tongling Changjiang River Bridge on Hefei-Fuzhou Railway is a steel truss girder cable-stayed bridge with three cable planes and with a main span 630 m. The Pier No. 3 of the north pylon of the bridge is supported on the foundation of round-ended caisson that was constructed by the scheme of "two-time positioning and quick landing of the caisson onto the riverbed by water pumping". To make sure that the caisson could be accurately landed onto the riverbed, the spatial model for the caisson and its tie anchor rope system was set up by the finite element software MIDAS 2006, the process of the landing of the caisson was simulated, the changing laws of the caisson offsetting and anchor rope forces in the process of the landing were analyzed and it was determined that the distance between the bottom of the caisson and the riverbed should be kept 2 m at the time the caisson was being positioned. To minimize the influences of the scouring, soil non-uniformity of the riverbed, waves and vortex vibration on the accurate landing of the caisson onto the riverbed, the measures of pumping water into the caisson for quick landing of the caisson, rectifying the offsetting of the caisson by winching the anchors, increasing the numbers and rigidity of the side anchors of the caisson and increasing the mass and damping of the caisson itself were respectively taken.%合福铁路铜陵长江大桥主桥为主跨630 m的三索面钢桁梁斜拉桥,其北桥塔3号墩采用圆端形沉井基础,沉井着床采用“二次定位、注水快速着床”的方案.为使沉井精确着床,采用MIDAS 2006有限元软件建立沉井和拉缆系统空间模型,模拟沉井着床过程,分析沉井着床过程中的偏移及拉缆索力变化规律,确定定位时沉井底与河床的距离为2 m.为减小冲刷、河床平面土质分布不均、波浪和涡激振动等对沉井精确着床的影响,分别采取了注水快速着床、绞锚纠偏回位、增加沉井边

  20. 后支点反吊三角托架挂篮技术研究%Study of Form Traveler with Rear Supports and Reversedly-Hung Triangular Brackets

    Institute of Scientific and Technical Information of China (English)

    胡若邻; 陈鸣

    2014-01-01

    The Second Penang Bridge is a three-span two-pylon cable-stayed bridge with a main span of 240 m and with double cable planes .The main girder belongs to the type of concrete edge beam and the bridge deck is 34 .6 m wide .To realize the asynchronous construction of the adjacent main girder sections ,avoid the condition that the prestress in the main girder will be shared by the bridge deck and weakened ,and overcome the problem of the need of reserving concrete post-cast-ing zone in the construction of using guyed form traveler with front supports ,a new type of form traveler with rear supports and reversedly-hung triangular brackets were developed .This type of form traveler has small self-weight and its reversedly-hung triangular brackets has rational load bearing performance ,therefore ,the stay force system transformation problem of the form traveler with front supports will be avoided .The overall stability and deformation resistance of the form traveler was advanced and optimized by optimizing the overall stability of the form traveler struc -ture and improving the load bearing capacity of hangers and the workmanship of the staggering of the construction joints .The form traveler was successfully used in the construction of the Second Penang Bridge in Malaysia .%马来西亚槟城二桥是一座主跨240 m 的三跨双塔双索面斜拉桥,采用混凝土边主梁形式,桥面宽34.6 m 。为实现相邻主梁节段异步施工,避免边主梁预应力被桥面板分摊削弱,同时克服前支点牵索挂篮施工中需预留后浇带混凝土的问题,开发了一种新型后支点反吊三角托架挂篮。该挂篮自重轻,反吊三角托架受力合理明确,可避免前支点挂篮斜拉索力系转换等问题。通过对该挂篮结构整体稳定性的优化、吊杆受力和施工接缝错台的工艺改进等措施,提升和优化了挂篮整体稳定性和抵抗变形能力,成功应用于马来西亚槟城二桥施工中。

  1. Floating Resistance Analysis for No .28 Pier Steel Caisson of Hutong Changjiang River Bridge%沪通长江大桥28号墩钢沉井浮运阻力分析

    Institute of Scientific and Technical Information of China (English)

    陈涛

    2015-01-01

    The main navigational channel bridge of Hutong Changjiang River Bridge is a steel truss girder cable‐stayed bridge with span arrangement of (142+462+1 092+462+142) m .The foundations of the pylon piers adopt caisson foundations ,among w hich the top plan dimension of steel caisson of pier No .28 is 86 .9 m by 58 .7 m ,and 44 m high .The steel caisson for the pier No .28 was fabricated in a dock and then transported to the bridge site by floating ,with a total floating weight of up to 14 500 t .To rationally allocate the floating tugboats and assure smooth floating ,the theoretical method ,numerical simulation method and physical model testing method were used to calculate the floating resistance of the steel caissons .Based on the comparative analy‐sis ,by modifying the head and end shapes of the boats ,the results gained by using the method presented in the Guidelines for Towage At Sea is approximate to those gained respectively by nu‐merical simulation and physical model testing ,w hich is proved applicable to the floating resistance calculation for the steel caisson of pier No .28 .It is proposed by calculation that the steel caissons have a draft of 8 m ,when the wind speed is at Grade 6 ,and the tugboat′s speed through water is 2 . 5 m/s ,the total resistance for a steel caisson is 2 167 kN under the condition of longitudinal to‐wing .The arrangement of the tugboats adopts the“7+1”mode ,namely one used as a backup tug‐boat ,the efficient output towing force is 3 060 kN ,and the maximum resistance of the towing is 2 326 .74 kN ,satisfying the floating requirements of the steel caisson .%沪通长江大桥主航道桥为(142+462+1092+462+142) m钢桁梁斜拉桥,桥塔墩基础采用沉井基础,其中28号墩钢沉井顶平面尺寸为86.9 m ×58.7 m ,高44 m。28号墩钢沉井在船坞内制造完后整体浮运至桥址处,浮运总重达14500 t。为合理地配置浮运拖轮,确保浮运顺利,采用理论方

  2. Study of Lining Concrete Arrangement for Multi-Cell Single Box Composite Girder with Corrugated Steel Webs%单箱多室波形钢腹板组合箱梁内衬混凝土布置方式研究

    Institute of Scientific and Technical Information of China (English)

    邓文琴; 张建东; 刘朵; 胡隽

    2016-01-01

    为优化波形钢腹板内衬混凝土组合结构受力,以南昌朝阳大桥通航孔桥———单箱多室波形钢腹板单索面多塔斜拉桥为工程背景,通过理论计算和有限元分析研究了单箱多室波形钢腹板组合箱梁内衬混凝土布置形式对结构抗剪性能的影响。结果表明:有无设置内衬混凝土对单箱多室波形钢腹板组合箱梁腹板剪应力水平较高的波形钢腹板影响较大,对腹板剪应力水平较低的波形钢腹板影响较小;内衬混凝土单侧设置和双侧设置波形钢腹板剪应力的影响相差不大;内衬混凝土双侧设置及仅有内衬混凝土无波形钢腹板设置对混凝土剪应力的影响相差较小;对单箱多室波形钢腹板组合箱梁高剪应力水平腹板内衬混凝土可以考虑双侧布置或仅设置混凝土腹板,不设置波形钢腹板;而剪应力水平较低的腹板则考虑设置单侧内衬混凝土。%To optimize the load bearing capacity of the corrugated steel web and lining concrete composite structure ,the navigational channel bridge of Nanchang Chaoyang Bridge was taken as the study background .The bridge is a multi‐pylon multi‐cell single box girder cable‐stayed bridge with corrugated steel webs and the stay cables are fanned out in single cable plane .The influence of the arrangement of lining concrete in the multi‐cell single box composite girder with corrugated steel webs on the anti‐shearing performance of the structure was studied via theoretical calculation and finite element analysis .The results indicate that the addition of lining concrete has significant influence on the corrugated steel webs with higher shearing stress in the multi‐cell single box gird‐er with corrugated steel webs ,but slight influence on the corrugated steel webs with lower stress level .No matter the lining concrete is added to a single side of the webs or to both the two sides of the webs ,the influence exerted

  3. 弹塑性钢减隔震支座在桥梁抗震设计中的应用%Application of Elasto-Plastic Steel Seismic Isolators to Bridge Anti-Seismic Design

    Institute of Scientific and Technical Information of China (English)

    高山; 彭泽友; 史春娟; 王永祥

    2015-01-01

    为了给桥梁抗震设计提供参考,以减轻桥梁结构在地震中遭受的损伤,介绍一种弹塑性钢减隔震支座(NDQZ)的结构特点及其减隔震原理,并以(83+140+83) m双塔双索面预应力混凝土斜拉桥为实例进行减隔震分析。采用有限元分析软件SAP2000建立全桥有限元模型,在E2地震状态下分别进行非减隔震支座桥梁和NDQZ支座桥梁地震动力时程分析。结果表明:NDQZ支座可实现全桥协同抗震,减隔震效果良好;采用NDQZ支座后,桥梁前3阶自振周期平均延长133%,在顺桥向和横桥向墩底弯矩分别减小了40%和83%,墩底剪力分别减小了39%和70%;承台底弯矩分别减小了39%和74%,承台底剪力分别减小了34%和60%;弯矩和剪力分布均匀。%To provide reference for bridge anti‐seismic design and reduce the damage that bridge suffers in earthquakes ,the structural features and principles of vibration mitigation and iso‐lation of a kind of elasto‐plastic steel seismic isolators (NDQZ)is introduced .A two‐pylon pres‐tressed concrete cable‐stayed bridge with span arrangement of (83+140+83) m and with double cable planes is cited as an example to conduct vibration mitigation and isolation analysis .T he finite element software SAP2000 was used to establish the finite element model of the whole bridge ,to carry out time‐history analysis of the bridge with bearings incapable of vibration mitigation and iso‐lation effect and the bridge with NDQZ under the E2 earthquake condition respectively .The re‐sults of the analysis indicate that the NDQZ bearings can realize the effect of the w hole‐bridge col‐laborative vibration resistance ,displaying sound vibration mitigation and isolation effect .When the NDQZ bearings are used ,the first three orders of bridge natural vibration period averagely ex‐tends 133% .The bending moments in the base of the piers along the bridge length

  4. 中朝鸭绿江界河公路大桥耐久性技术研究%Study of Durability Enhancing Techniques for Yalu Boundary River Highway Bridge Connecting China and DPR Korea

    Institute of Scientific and Technical Information of China (English)

    闫大伟

    2014-01-01

    The Yalu Boundary River Highway Bridge is a two-pylon steel box girder cable-stayed bridge with a main span of 636 m .The bridge site is located where the climate is harsh in winter and the meteorological condition is complex ,creating challenges for the durability of the bridge .By the combined use of both the theoretical and experimental methods ,a number of studies were conducted ,including the mixing proportion design of the frost-resisting high performance concrete that has high flow state and is able to resist sea water erosion ,the feasibility of - 10 ~ - 5℃ low temperature welding techniques and the externally-installed vibration absorbers for stay ca-bles .The results of the study indicate that the chosen compressive strength ,shrinking behavior , impermeability and frost and thaw resistant performance of concrete all have superior indexes which meet the design requirements .The trial plates were made to take shape by the welding tech-niques applied to real bridges .The tensile strength in the welding joints of trial plates and the yielding strength ,tensile strength and the extension rate after break of the metals in the welding joints could meet the requirements .The feasigility of - 10 ~ - 5 ℃ low temperature welding is proved feasible .And according to the testing results ,the quality control measures for the steel box girder heat preservation ,preheating and other low temperature welding were determined . The pendulum leverage mass vibration dampers featuring the eddy current damping and friction damp -ing for stay cables have sound vibration damping effect and temperature stability .The application of the aforementioned techniques ensures that the bridge has sound durability .%中朝鸭绿江界河公路大桥为主跨636 m 的双塔双索面钢箱梁斜拉桥,桥址处气候严寒,气象条件复杂。为解决桥梁耐久性问题,通过理论与试验相结合的方法,进行高流态耐海水侵蚀的抗冻性高性

  5. Assessment of Postflight Locomotor Performance Utilizing a Test of Functional Mobility: Strategic and Adaptive Responses

    Science.gov (United States)

    Warren, L. E.; Mulavara, A. P.; Peters, B. T.; Cohen, H. S.; Richards, J. T.; Miller, C. A.; Brady, R.; Ruttley, T. M.; Bloomberg, J. J.

    2006-01-01

    have further analyzed the FMT data to characterize strategic and adaptive components during the postflight readaptation period. Crewmembers walked at a preferred pace through an obstacle course set up on a base of 10 cm thick medium density foam (Sunmate Foam, Dynamic Systems, Inc., Leicester, NC). The 6.0m X 4.0m course consisted of several pylons made of foam; a Styrofoam barrier 46.0cm high that crewmembers stepped over; and a portal constructed of two Styrofoam blocks, each 31cm high, with a horizontal bar covered by foam and suspended from the ceiling which was adjusted to the height of the crewmember s shoulder. The portal required crewmembers to bend at the waist and step over a barrier simultaneously. All obstacles were lightweight, soft and easily knocked over. Crewmembers were instructed to walk through the course as quickly and as safely as possible without touching any of the objects on the course. This task was performed three times in the clockwise direction and three times in the counterclockwise direction that was randomly chosen. The dependent measures for each trial were: time to complete the course (seconds) and the number of obstacles touched or knocked down. For each crewmember, the time to complete each FMT trial from postflight days 1, 2, 4, 7 and 25 were further analyzed. A single logarithmic curve using a least squares calculation was fit through these data to produce a single comprehensive curve (macro). This macro curve composed of data spanning 25 days, illustrates the re-adaptive learning function over the longer time scale term. Additionally, logarithmic curves were fit to the 6 data trials within each individual post flight test day to produce 5 separate daily curves. These micro curves, produced from data obtained over the course of minutes, illustrates the strategic learning function exhibited over a relative shorter time scale. The macro curve for all subjects exhibited adaptive motor learning patterns over the 25 day period. Howev, 9

  6. Validation of a New Developed Aerodynamics Analysis Toolkit for Civil Aircraft Configurations%运输类飞机气动力分析软件ATTF的开发与验证

    Institute of Scientific and Technical Information of China (English)

    李广宁; 李凤蔚; 周志宏

    2011-01-01

    local time-stepping, implicit variable-coefficient residual smoothing and multigrid are applied to accelerate the convergence.The solver utilizes the technique of dynamic memory space management to optimize the limited memory space for a small computer, and only one executable file is needed to run different flow simulations with different size of data and various grid topologies, and the executable file only need an input file including correct boundary conditions and necessary control information for a given case. To evaluate the capacity and efficiency of ATTF for complex configurations of civil transport aircraft, the transonic flow simulations around DLR-F6 wing-body-nacelle-pylon (WBNP) configuration from the Second AIAA Drag Prediction Workshop (DPW-2), which is a wide-body Airbus-type transport aircraft model, are performed. The computational results are compared with the experimental results from ONERA S2MA transonic wind tunnel in France and the computational results from two other CFD software:CFL3D and TRIP2.0 (The TRIP2.0 is developed in China Aerodynamics Research and Development Center). The final results show that the code we developed can be used to obtain coincident result with experiment and other CFD softwares, showing preliminarily that our code is reliable.

  7. El puente de Saint-Nazaire - Saint-Brévin – Francia

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1976-05-01

    Full Text Available As a consequence of the industrial and tourist development of the region, it was necessary to construct a bridge across the Loire taking into account conditions such as the geological nature of the Loire river bed, the passing of up to 200,000 t oil tankers and other factors which were of utmost importance for the design and the subsequent construction. The work consist of two access viaducts and the central metal bridge. The viaduct, the outlines of which are curved in mutually opposite senses, are of prestressed concrete. They are made up equal spans, each of which has a length of 50.70 m between the pile axes, with in all 22 on the north side and 30 on the south side. Each span consists of: 4 prefabricated girders which are joined at the ends by tie members; between the girders there is a 0.50 cm thick fill layer, over which there is a reinforced concrete slab. The supporting piers, also of reinforced concrete, have a foundation of piles which generally speaking rest on the rocky substratum of the riverbed. The metal part rests upon two main piers, situated on either side, with same type of foundation as mentioned above. On these are located inverted V-shape pylons, with a short vertical element, to which the cables that support the centre bridge deck are anchored, formed by 96 m and 16 m long spans, welded together after having been lifted to their final level. This project —the greatest in France and the one that has the greatest clear span among the works of this kind— has required three years of work utilizing the most modern techniques and systems. More than 80,000 m2 of concrete and more than 17,000 t of different kinds of steel have been used.Como consecuencia del desarrollo industrial y turístico de la región, fue preciso construir un puente sobre el Loira, contando con condicionantes tales como la naturaleza geológica del lecho del Loira, el paso de petroleros de hasta 200.000 t, y otros factores que influyeron grandemente

  8. Effect of different transport conditions and media on Helicobacter pylori isolation%幽门螺杆菌不同运送条件及培养基分离效果的比较

    Institute of Scientific and Technical Information of China (English)

    王琼; 杨杰; 潘科; 黄亚琴; 陈峥宏; 王菲; 綦廷娜

    2016-01-01

    AIM:To optimize transport conditions and medium for Helicobacter pylori (H.pylori) isolation and culture.METHODS:Live H.pylori bacteria were added into Broth medium with sucrose (1 g/mL) and 50% (mL/mL) calf serum and skim milk quantitatively.The bacteria in transport media were placed at different temperatures in different atmospheres for 6 hours,and then inoculated onto Columbia agar medium supplemented with 10% defibrinated sheep blood and cultured at 37 ℃ micro-aerobically for 5 d.H.pylori colonies were counted and compared.Twenty gastric mucosa specimens from patients diagnosed with gastritis or gastric ulcer were inoculated into Columbia agar and hydrolyzed casein agar supplemented with 10% defibrinated sheep blood and selective antibiotics,then incubated for 5 d at 37 ℃ micro-aerobically.Growth of H.pylori was observed and compared.RESULTS:The number of live bacteria in calf serum medium was higher than that in skim milk.The number of live bacteria in micro-aerobic and candle jar was higher than that in air and transporting media covered with paraffin oil.The number of bacteria in calf serum media placed micro-aerobically at 37 ℃ (or 26 ℃) was higher than that at 6 ℃ (P <0.05).There was no significant difference in the number of live bacteria when placed micro-aerobically or in candle jar (P > 0.05).The positive rate (75%) of 20 samples isolated with hydrolyzed casein blood agar was higher than that isolated with Columbia blood agar (45%)(x2=4.401,P < 0.05).CONCLUSION:H.pylori clinical samples can be placed in calf serum medium in microaerobic conditions and transported to the laboratory for isolation.Hydrolyzed casein agar supplemented with 10% defibrinated sheep blood is better than Columbia agar medium supplemented with 10% defibrinated sheep blood for H.pylori isolation.%目的:探索幽门螺杆菌(Helicobacter pylori,H pylon)的适宜运送条件及培养基.方法:将H.pylori实验菌株新鲜菌液分别定量加入含1

  9. Locomotor Dysfunction after Long-duration Space Flight and Development of Countermeasures to Facilitate Faster Recovery

    Science.gov (United States)

    Mulavara, Ajitkumar; Wood, Scott; Cohen, Helen; Bloomberg, Jacob

    2012-07-01

    movement control and a functional mobility test to investigate overall functional locomotor ability. Postflight sessions were given on days 1, 2, 4, 7 after their return. Subjects walked on a treadmill driven at 1.8 m/s while performing a visual task. Motion data from head and trunk segmental motion data were obtained to calculate the angular head pitch (HP) movements during walking trials while subjects performed the visual task, to estimate the contributions of vestibular reflexive mechanisms in HP movements. Astronauts showed a heterogeneous response pattern of both increases and decreases in the amplitude of HP movement. We investigated the underlying mechanisms of this heterogeneity in postflight responses in head movement control by examining data obtained using the same experimental test paradigm on a vestibular clinical population (VC) and in normal subjects undergoing adaptation to acute body load support unloading. Results showed that exposure to unloaded locomotion caused a significant increase in HP movements, whereas in the VC patients the HP movements were significantly decreased. We infer that BLS-mediated somatosensory input centrally modulates vestibular input and can adaptively modify head-movement control during locomotion. Thus, space flight may cause a central adaptation of the converging vestibular and body load-sensing somatosensory systems. To investigate changes in functional mobility astronaut subjects walked at their preferred pace around an obstacle course consisting of several pylons and obstacles set up on a foam floor, which provided an unstable walking surface. Subjects were instructed to walk around the course as fast as possible without touching any of the objects on the course for a total of six individual trials per test session. One of the dependent measures was time to complete the course (TCC, sec). The learning rate over the six trials performed on preflight and the first day after landing (micro curve) was used to characterize the

  10. Study of Dynamic Performance Finite Element Modeling Methods for Box-Truss Composite Girder Railway Cable-Stayed Bridge%箱桁组合梁铁路斜拉桥动力特性有限元建模方法研究

    Institute of Scientific and Technical Information of China (English)

    张无畏; 胡腾飞; 陈长胜; 荣浩

    2016-01-01

    为实现箱桁组合梁铁路斜拉桥动力特性的精准模拟计算,对箱桁组合梁开口断面斜拉桥空间杆系模型、空间板梁组合模型和空间板壳模型3种有限元建模方法进行研究。以某跨径布置为(98+140+406+406+140+98) m的三塔双主跨箱桁组合梁铁路斜拉桥为背景,采用子空间迭代方法对比分析了不同模型的模态特性,并在此基础上计算了不同模型主梁单位长度的等效质量及其惯性矩。研究结果表明:3种模型计算得到的模态分析结果基本吻合,空间板梁组合模型和空间板壳模型得到的频率及主梁等效质量基本相同,但空间杆系模型不能准确得到高阶侧弯模态的主梁等效均布质量。作为特例,进一步对无桁架钢箱梁开口断面斜拉桥的动力特性进行分析,结果表明:空间板梁组合模型和空间板壳模型吻合良好,但空间杆系模型得到的1阶扭转模态下的主梁等效均布质量惯性矩误差接近9%;桁架对主梁的侧弯基频影响较小,但能提高主梁的竖弯基频和扭转基频,有利于桥梁抗风。%To realize the accurate simulation calculation of the dynamic performance of box‐truss composite girder railway cable‐stayed bridge ,the three finite element modeling schemes of the box‐truss composite girder cable‐stayed bridge with open cross section are studied ,including the spatial bar element model ,combined space plate and beam element model and spatial shell ele‐ment model .A three‐pylon two main spans box‐truss composite girder railway cable‐stayed bridge with span arrangement of (98+140+406+406+140+98) m was taken as the study background . The sub‐spatial iterative method was used to comparatively analyze the modal characteristics of the different models ,and based on w hich the unit length equivalent mass and inertia moment of the different main girder models were calculated .The results of the

  11. Optimal design and routing of power lines; ecological, technical and economic perspectives (OPTIPOL). Progress report 2009

    Energy Technology Data Exchange (ETDEWEB)

    Bevanger, K.; Bartzke, G.; Broeseth, H.; Gjershaug, J.O.; Hanssen, F.; Jacobsen, K.-O.; Kvaloey, P.; May, R.; Nygaard, T.; Pedersen, H.C.; Reitan, O.; Refsnaes, S.; Stokke, S.; Vang, R.

    2009-12-15

    mitigating measures. The study includes use of GPS-satellite telemetry to see how the eagle owls use the pylons during hunt-ing activities. This will also give data on eagle-owl movements and electrocution rate. In 2009 3 adult and 4 juvenile eagle owls were equipped with GPS-radio transmitters. (Author)

  12. DAST Mated to B-52 on Ramp - Close-up

    Science.gov (United States)

    1979-01-01

    Technicians mount a BQM-43 Firebee II drone on the wing pylon of NASA's B-52B launch aircraft. The drone was test flown as part of the Drones for Aerodynamic and Structural Testing (DAST) program. Research flights of drones with modified wings for the DAST program were conducted from 1977 to 1983. After the initial flights of Firebee II 72-1564, it was fitted with the Instrumented Standard Wing (also called the 'Blue Streak' wing). The first free flight attempt on March 7, 1979, was aborted before launch due to mechanical problems with the HH-53 recovery helicopter. The next attempt, on March 9, 1979, was successful. These are the image contact sheets for each image resolution of the NASA Dryden Drones for Aerodynamic and Structural Testing (DAST) Photo Gallery. From 1977 to 1983, the Dryden Flight Research Center, Edwards, California, (under two different names) conducted the DAST Program as a high-risk flight experiment using a ground-controlled, pilotless aircraft. Described by NASA engineers as a 'wind tunnel in the sky,' the DAST was a specially modified Teledyne-Ryan BQM-34E/F Firebee II supersonic target drone that was flown to validate theoretical predictions under actual flight conditions in a joint project with the Langley Research Center, Hampton, Virginia. The DAST Program merged advances in electronic remote control systems with advances in airplane design. Drones (remotely controlled, missile-like vehicles initially developed to serve as gunnery targets) had been deployed successfully during the Vietnamese conflict as reconnaissance aircraft. After the war, the energy crisis of the 1970s led NASA to seek new ways to cut fuel use and improve airplane efficiency. The DAST Program's drones provided an economical, fuel-conscious method for conducting in-flight experiments from a remote ground site. DAST explored the technology required to build wing structures with less than normal stiffness. This was done because stiffness requires structural weight but

  13. EDITORIAL: Message from the Editor Message from the Editor

    Science.gov (United States)

    Thomas, Paul

    2012-01-01

    At the time of writing, the construction of ITER is making, quite literally, visible progress; buildings have gone up, the tokamak pit has been equipped with the seismic pads and pylons have been put in place for the high tension input to the power supplies. Most of the main procurement arrangements have been let and we will see an increasing volume of deliveries to the ITER site over the coming years. In addition, the National Ignition Facility has started full operation and will undoubtedly see important results coming from it in 2012. These projects are important reminders of what a monumental endeavour we are all engaged in and the potential of nuclear fusion to improve the long-term condition of the human race. We can be proud, therefore, that the Nuclear Fusion journal makes such an important contribution to controlled fusion programmes and is maintaining its position as the leading journal in the field. More than 350 articles are submitted each year from over 40 countries. Nuclear Fusion continues to be the most highly cited journal in the field, with an impact factor of 3.303, as listed in the ISI 2010 Science Citation Index. The journal depends on its authors and referees for its success and so I would like to thank them all for their hard work in 2011, which should maintain the level of readership and the citation indices for years to come. I sincerely hope that 2012 will be as good. Refereeing The Nuclear Fusion editorial office understands how much effort is required of our referees. The Editorial Board decided that an expression of thanks to our most loyal referees is appropriate and so, since January 2005, we have been offering the top ten most active referees over the past year a personal subscription to Nuclear Fusion with electronic access for one year, free of charge. This year, three of the top referees have reviewed five manuscripts in the period November 2010 to November 2011 and provided excellent advice to the authors. We have excluded our

  14. Pre- and post-construction studies of conflicts between birds and wind turbines in coastal Norway (BirdWind)

    Energy Technology Data Exchange (ETDEWEB)

    Bevanger, K.; Berntsen, F.; Clausen, S.; Dahl, E.L.; Flagstad, Oe.; Follestad, A.; Halley, D.; Hanssen, F.; Hoel, P.L.; Johnsen, L.; Kvaloey, P.; May, R.; Nygaard, T.; Pedersen, H.C.; Reitan, O.; Steinheim, Y.; Vang, R.

    2009-12-15

    connection to the planned extension of the existing power plant on Hitra I; the Hitra II Wind-Power Plant. Since 2003, 50 nestlings of white-tailed eagle have been equipped with satellite transmitters. In 2009, eight WTE nestlings were tagged, six with solar-powered and two with battery-powered transmitters. One was tagged within the wind-power plant, the others in close vicinity of it. The solar-powered transmitters used in 2009 were programmed to give one position per hour during summer in order to have finer resolution of movements for risk-modeling purposes. During winter less frequent downloading is scheduled, due to low light and poor battery-charging. One of the tagged nestlings was found killed by a turbine October 7. We have continued to collect feathers from active nests and chicks also in 2009, as well as from eagles killed in collisions with wind turbines. DNA-analyses from bones of six eagles killed by electrocution on power-line pylons on Smoela will also be included. For increased efficiency in the laboratory, and to streamline the production of DNA-data, the use of an extraction robot has been implemented. All WTE nest sites on Smoela were surveyed during the summer. Territorial activity, identified by either moulted adult feathers, chicks in the nest or fresh nest material, was confirmed in 61 different territories on the main island and in the surrounding archipelago. In these territories 27 chicks from 21 different clutches were recorded. This is the second highest number of chicks recorded ever on Smoela, giving a re-productive output of 0.44 chicks/confirmed occupied territory. In order to investigate behavioural differences for the WTE related to the distance from the turbines, data on flight activity (moving flight, social behaviour and soaring) and flight height (below, in and above the rotor zone) were collected at 12 vantage points, 6 from inside the wind-power plant area and 6 from control areas close to the power-plant area. The results indicate