WorldWideScience

Sample records for aircraft by speed

  1. 14 CFR 91.117 - Aircraft speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Aircraft speed. 91.117 Section 91.117... speed. (a) Unless otherwise authorized by the Administrator, no person may operate an aircraft below 10... than the maximum speed prescribed in this section, the aircraft may be operated at that minimum speed....

  2. Analytical study of interior noise control by fuselage design techniques on high-speed, propeller-driven aircraft

    Science.gov (United States)

    Revell, J. D.; Balena, F. J.; Koval, L. R.

    1980-01-01

    The acoustical treatment mass penalties required to achieve an interior noise level of 80 dBA for high speed, fuel efficient propfan-powered aircraft are determined. The prediction method used is based on theory developed for the outer shell dynamics, and a modified approach for add-on noise control element performance. The present synthesis of these methods is supported by experimental data. Three different sized aircraft are studied, including a widebody, a narrowbody and a business sized aircraft. Noise control penalties are calculated for each aircraft for two kinds of noise control designs: add-on designs, where the outer wall structure cannot be changed, and advanced designs where the outer wall stiffness level and the materials usage can be altered. For the add-on designs, the mass penalties range from 1.7 to 2.4 percent of the takeoff gross weight (TOGW) of the various aircraft, similar to preliminary estimates. Results for advanced designs show significant reductions of the mass penalties. For the advanced aluminum designs the penalties are 1.5% of TOGW, and for an all composite aircraft the penalties range from 0.74 to 1.4% of TOGW.

  3. Lifetime and structures of TLEs captured by high-speed camera on board aircraft

    Science.gov (United States)

    Takahashi, Y.; Sanmiya, Y.; Sato, M.; Kudo, T.; Inoue, T.

    2012-12-01

    Temporal development of sprite streamer is the manifestation of the local electric field and conductivity. Therefore, in order to understand the mechanisms of sprite, which show a large variety in temporal and spatial structures, the detailed analysis of both fine and macro-structures with high time resolution are to be the key approach. However, due to the long distance from the optical equipments to the phenomena and to the contamination by aerosols, it's not easy to get clear images of TLEs on the ground. In the period of June 27 - July 10, 2011, a combined aircraft and ground-based campaign, in support of NHK Cosmic Shore project, was carried with two jet airplanes under collaboration between NHK, Japan Broadcasting Corporation, and universities. On 8 nights out of 16 standing-by, the jets took off from the airport near Denver, Colorado, and an airborne high speed camera captured over 60 TLE events at a frame rate of 8000-10,000 /sec. Some of them show several tens of streamers in one sprite event, which repeat splitting at the down-going end of streamers or beads. The velocities of the bottom ends and the variations of their brightness are traced carefully. It is found that the top velocity is maintained only for the brightest beads and others become slow just after the splitting. Also the whole luminosity of one sprite event has short time duration with rapid downward motion if the charge moment change of the parent lightning is large. The relationship between diffuse glows such as elves and sprite halos, and subsequent discrete structure of sprite streamers is also examined. In most cases the halo and elves seem to show inhomogenous structures before being accompanied by streamers, which develop to bright spots or streamers with acceleration of the velocity. Those characteristics of velocity and lifetime of TLEs provide key information of their generation mechanism.

  4. Small unmanned aircraft ballistic impact speed

    DEFF Research Database (Denmark)

    La Cour-Harbo, Anders

    2018-01-01

    A study of how smaller unmanned aircraft will fall in case of failure. The aim is to determine the impact speed of a drone givens its general shape and aerodynamic behavior. This will include both CFD simulations and real world test of ballistic drops of smaller drones.......A study of how smaller unmanned aircraft will fall in case of failure. The aim is to determine the impact speed of a drone givens its general shape and aerodynamic behavior. This will include both CFD simulations and real world test of ballistic drops of smaller drones....

  5. High-Speed Propeller for Aircraft

    Science.gov (United States)

    Sagerser, D. A.; Gatzen, B. S.

    1986-01-01

    Engine efficiency increased. Propeller blades required to be quite thin and highly swept to minimize compressibility losses and propeller noise during high-speed cruise. Use of 8 or 10 blades with highpropeller-power loading allows overall propeller diameter to be kept relatively small. Area-ruled spinner and integrated nacelle shape reduce compressibility losses in propeller hub region. Finally, large modern turboshaft engine and gearbox provide power to advanced propeller. Fuel savings of 30 to 50 percent over present systems anticipated. Propfan system adaptable to number of applications, such as highspeed (subsonic) business and general-aviation aircraft, and military aircraft including V/STOL.

  6. Conceptual design of high speed supersonic aircraft: A brief review on SR-71 (Blackbird) aircraft

    Science.gov (United States)

    Xue, Hui; Khawaja, H.; Moatamedi, M.

    2014-12-01

    The paper presents the conceptual design of high-speed supersonic aircraft. The study focuses on SR-71 (Blackbird) aircraft. The input to the conceptual design is a mission profile. Mission profile is a flight profile of the aircraft defined by the customer. This paper gives the SR-71 aircraft mission profile specified by US air force. Mission profile helps in defining the attributes the aircraft such as wing profile, vertical tail configuration, propulsion system, etc. Wing profile and vertical tail configurations have direct impact on lift, drag, stability, performance and maneuverability of the aircraft. A propulsion system directly influences the performance of the aircraft. By combining the wing profile and the propulsion system, two important parameters, known as wing loading and thrust to weight ratio can be calculated. In this work, conceptual design procedure given by D. P. Raymer (AIAA Educational Series) is applied to calculate wing loading and thrust to weight ratio. The calculated values are compared against the actual values of the SR-71 aircraft. Results indicates that the values are in agreement with the trend of developments in aviation.

  7. Titanium Alloys and Processing for High Speed Aircraft

    Science.gov (United States)

    Brewer, William D.; Bird, R. Keith; Wallace, Terryl A.

    1996-01-01

    Commercially available titanium alloys as well as emerging titanium alloys with limited or no production experience are being considered for a variety of applications to high speed commercial aircraft structures. A number of government and industry programs are underway to improve the performance of promising alloys by chemistry and/or processing modifications and to identify appropriate alloys and processes for specific aircraft structural applications. This paper discusses some of the results on the effects of heat treatment, service temperatures from - 54 C to +177 C, and selected processing on the mechanical properties of several candidate beta and alpha-beta titanium alloys. Included are beta alloys Timetal 21S, LCB, Beta C, Beta CEZ, and Ti-10-2-3 and alpha-beta alloys Ti-62222, Ti-6242S, Timetal 550, Ti-62S, SP-700, and Corona-X. The emphasis is on properties of rolled sheet product form and on the superplastic properties and processing of the materials.

  8. Determining the approach speed envelope of carrier aircraft

    Institute of Scientific and Technical Information of China (English)

    Geng Jianzhong; Yao Hailin; Duan Zhuoyi

    2013-01-01

    Many factors,such as deck motion and air wave,influence the determination of the approach speed which has an important effect on landing safety. Until recently,there are no design criteria about approach speed of carrier aircraft in the current standards and available publications. Therefore,the requirements of stall margin, longitudinal acceleration ability,altitude correction and field-of-view on approach speed were researched. Based on the flight dynamics model,the flight simulations were conducted to study the effect of the response time of en-gine,wave off requirements,elevator efficiency and deflection rate on the approach speed. The results presented that the approach longitudinal acceleration and altitude correction ability had crucial influence on the approach speed envelope of the aircraft. The limitations of the control requirements,field-of-view requirements and gear were also given through the simulation and analysis. Based on the above results,the approach speed envelope were determined.

  9. Relationship between structures of sprite streamers and inhomogeneity of preceding halos captured by high-speed camera during a combined aircraft and ground-based campaign

    Science.gov (United States)

    Takahashi, Y.; Sato, M.; Kudo, T.; Shima, Y.; Kobayashi, N.; Inoue, T.; Stenbaek-Nielsen, H. C.; McHarg, M. G.; Haaland, R. K.; Kammae, T.; Yair, Y.; Lyons, W. A.; Cummer, S. A.; Ahrns, J.; Yukman, P.; Warner, T. A.; Sonnenfeld, R. G.; Li, J.; Lu, G.

    2011-12-01

    The relationship between diffuse glows such as elves and sprite halos and subsequent discrete structure of sprite streamers is considered to be one of the keys to solve the mechanism causing a large variation of sprite structures. However, it's not easy to image at high frame rate both the diffuse and discrete structures simultaneously, since it requires high sensitivity, high spatial resolution and high signal-to-noise ratio. To capture the real spatial structure of TLEs without influence of atmospheric absorption, spacecraft would be the best solution. However, since the imaging observation from space is mostly made for TLEs appeared near the horizon, the range from spacecraft to TLEs becomes large, such as few thousand km, resulting in low spatial resolution. The aircraft can approach thunderstorm up to a few hundred km or less and can carry heavy high-speed cameras with huge size data memories. In the period of June 27 - July 10, 2011, a combined aircraft and ground-based campaign, in support of NHK Cosmic Shore project, was carried with two jet airplanes under collaboration between NHK (Japan Broadcasting Corporation) and universities. On 8 nights out of 16 standing-by, the jets took off from the airport near Denver, Colorado, and an airborne high speed camera captured over 40 TLE events at a frame rate of 8300 /sec. Here we introduce the time development of sprite streamers and the both large and fine structures of preceding halos showing inhomogeneity, suggesting a mechanism to cause the large variation of sprite types, such as crown like sprites.

  10. An economic model for evaluating high-speed aircraft designs

    Science.gov (United States)

    Vandervelden, Alexander J. M.

    1989-01-01

    A Class 1 method for determining whether further development of a new aircraft design is desirable from all viewpoints is presented. For the manufacturer the model gives an estimate of the total cost of research and development from the preliminary design to the first production aircraft. Using Wright's law of production, one can derive the average cost per aircraft produced for a given break-even number. The model will also provide the airline with a good estimate of the direct and indirect operating costs. From the viewpoint of the passenger, the model proposes a tradeoff between ticket price and cruise speed. Finally all of these viewpoints are combined in a Comparative Aircraft Seat-kilometer Economic Index.

  11. Hybrid Aircraft for Heavy Lift / High Speed Strategic Mobility

    Science.gov (United States)

    2011-04-01

    Aircraft such as the E-2 Hawkeye, E-3 Sentry, E-6 Mercury , and E-8 Joint STARS burn a significant amount of fuel to allow their persistence; this would...these programs involved the size and weight reduction required to fit the laser into an existing aircraft. Eliminating this need by carrying the laser...Mahony, Melissa. “U.S. Army to get new hybrid blimps for Afghanistan.” Smart Planet , 25 June 2010. http://www.smartplanet.com/business/blog

  12. 基于航空噪声指标的高速列车观光区噪声评价%Noise Evaluation in the Tourist Cabin of High-speed Train by Using Aircraft Noise Criterion

    Institute of Scientific and Technical Information of China (English)

    张捷; 肖新标; 张玉梅; 王瑞乾; 王谛; 金学松

    2013-01-01

    Based on field measurements,the noise characteristics in the tourist cabin of a high-speed train are analyzed at a high running speed between 300 to 400 km/h.So far,there is still no a unified criterion in the word to evaluate the noise level in the carriage of high-speed train reasonably,while A-weighted sound level has a shortcoming in the noise evaluation.In order to further clear the shortcoming,A-weighted sound level is discussed through the detailed contrast to white noise combined with increasing sound level in different frequency bands.An aircraft noise evaluation index is used to evaluate the interior noise of the high-speed train.The obtained results indicate that:the noise in the tourist cabin of the high-speed train is dominated by the components of low and middle frequencies.Such a noise would be underestimated when A-weighted sound level is used.There is high similarity of frequency characteristics between interior noise of high-speed train and it of aircraft.The aircraft noise evaluation index is more suitable for the characteristic evaluation of interior noise of high-speed train.This paper could provide evidence for framing new proper noise evaluation criterion for high-speed train.%基于现场测试结果,对300~400 km/h速度下高速列车观光区噪声进行分析,明确车内噪声动态特性.由于国内外还没有统一的高速列车车内噪声评价标准,传统的A计权声压级又在噪声评价中存在不足之处.为研究A计权声压级是否适合高速列车车内噪声评价,通过白噪声对比、分频段声压级比例增加等方法,讨论使用A计权声压级评价车内噪声时的不足之处.运用航空噪声评价指标对高速列车车内噪声进行评价研究.研究结果表明,300 km/h以上高速列车车内噪声具有显著的中低频特性,使用A计权声压级评价会低估车内噪声水平.高速列车观光区噪声频谱特性和飞机舱内噪声频谱特性具有很高的相似性,选择

  13. Aircraft

    Science.gov (United States)

    Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.

    1998-09-22

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing`s top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gases for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well. 31 figs.

  14. 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.

  15. Variable-Speed Induction Motor Drives for Aircraft Environmental Control Compressors

    Science.gov (United States)

    Mildice, J. W.; Hansen, I. G.; Schreiner, K. E.; Roth, M. E.

    1996-01-01

    New, more-efficient designs for aircraft jet engines are not capable of supplying the large quantities of bleed air necessary to provide pressurization and air conditioning for the environmental control systems (ECS) of the next generation of large passenger aircraft. System analysis and engineering have determined that electrically-driven ECS can help to maintain the improved fuel efficiencies; and electronic controllers and induction motors are now being developed in a NASA/NPD SBIR Program to drive both types of ECS compressors. Previous variable-speed induction motor/controller system developments and publications have primarily focused on field-oriented control, with large transient reserve power, for maximum acceleration and optimum response in actuator and robotics systems. The application area addressed herein is characterized by slowly-changing inputs and outputs, small reserve power capability for acceleration, and optimization for maximum efficiency. This paper therefore focuses on the differences between this case and the optimum response case, and shows the development of this new motor/controller approach. It starts with the creation of a new set of controller requirements. In response to those requirements, new control algorithms are being developed and implemented in an embedded computer, which is integrated into the motor controller closed loop. Buffered logic outputs are used to drive the power switches in a resonant-technology, power processor/motor-controller, at switching/resonant frequencies high enough to support efficient high-frequency induction motor operation at speeds up to 50,000-RPA

  16. 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.

  17. High speed wind tunnel tests of the PTA aircraft. [Propfan Test Assessment Program

    Science.gov (United States)

    Aljabri, A. S.; Little, B. H., Jr.

    1986-01-01

    Propfans, advanced highly-loaded propellers, are proposed to power transport aircraft that cruise at high subsonic speeds, giving significant fuel savings over the equivalent turbofan-powered aircraft. NASA is currently sponsoring the Propfan Test Assessment Program (PTA) to provide basic data on the structural integrity and acoustic performance of the propfan. The program involves installation design, wind-tunnel tests, and flight tests of the Hamilton Standard SR-7 propfan in a wing-mount tractor installation on the Gulfstream II aircraft. This paper reports on the high-speed wind-tunnel tests and presents the computational aerodynamic methods that were employed in the analyses, design, and evaluation of the configuration. In spite of the complexity of the configuration, these methods provide aerodynamic predictions which are in excellent agreement with wind-tunnel data.

  18. NASA-UVa light aerospace alloy and structures technology program supplement: Aluminum-based materials for high speed aircraft

    Science.gov (United States)

    Starke, E. A., Jr. (Editor)

    1995-01-01

    This report on the NASA-UVa light aerospace alloy and structure technology program supplement: Aluminum-Based Materials for High Speed Aircraft covers the period from July 1, 1992. The objective of the research is to develop aluminum alloys and aluminum matrix composites for the airframe which can efficiently perform in the HSCT environment for periods as long as 60,000 hours (certification for 120,000 hours) and, at the same time, meet the cost and weight requirements for an economically viable aircraft. Current industry baselines focus on flight at Mach 2.4. The research covers four major materials systems: (1) Ingot metallurgy 2XXX, 6XXX, and 8XXX alloys, (2) Powder metallurgy 2XXX alloys, (3) Rapidly solidified, dispersion strengthened Al-Fe-X alloys, and (4) Discontinuously reinforced metal matrix composites. There are ten major tasks in the program which also include evaluation and trade-off studies by Boeing and Douglas aircraft companies.

  19. High-speed rail with emerging automobiles and aircraft can reduce environmental impacts in California’s future

    Science.gov (United States)

    Chester, Mikhail; Horvath, Arpad

    2012-09-01

    Sustainable mobility policy for long-distance transportation services should consider emerging automobiles and aircraft as well as infrastructure and supply chain life-cycle effects in the assessment of new high-speed rail systems. Using the California corridor, future automobiles, high-speed rail and aircraft long-distance travel are evaluated, considering emerging fuel-efficient vehicles, new train designs and the possibility that the region will meet renewable electricity goals. An attributional per passenger-kilometer-traveled life-cycle inventory is first developed including vehicle, infrastructure and energy production components. A consequential life-cycle impact assessment is then established to evaluate existing infrastructure expansion against the construction of a new high-speed rail system. The results show that when using the life-cycle assessment framework, greenhouse gas footprints increase significantly and human health and environmental damage potentials may be dominated by indirect and supply chain components. The environmental payback is most sensitive to the number of automobile trips shifted to high-speed rail, and for greenhouse gases is likely to occur in 20-30 years. A high-speed rail system that is deployed with state-of-the-art trains, electricity that has met renewable goals, and in a configuration that endorses high ridership will provide significant environmental benefits over existing modes. Opportunities exist for reducing the long-distance transportation footprint by incentivizing large automobile trip shifts, meeting clean electricity goals and reducing material production effects.

  20. 航空用永磁无刷电机复合驱动中转速波动研究%Analysis of Speed Fluctuation of Brushless PM Motor in Aircraft by Compound Driven

    Institute of Scientific and Technical Information of China (English)

    吕永健; 李飞; 解亮

    2011-01-01

    This paper analysed the sine/square wave compound driven for brushless PM motors in aircraft EMA, deduced the dynamical equation of the speed during the switch process and researched the major factors which affect the speed fluctuation. The simulation model of compound driven for brushless PM motor and the platform of the motion control system for universal motors were established. The results of the analysis, simulations and experiments prove that the speed fluctuation can be controlled within acceptable limits and the compound driven for brushless PM motor is feasibility.%研究了航空EMA用永磁无刷电机正弦波/方波复合驱动策略,推导了永磁无刷电机在驱动方式切换时的转速动态方程,分析了影响切换过程中转速波动的主要因素.建立了永磁无刷电机复合驱动的仿真模型和实验平台,仿真和实验结果表明,正弦波/方波复合驱动时的转速波动可以控制在允许的范围内,验证了复合驱动控制策略的有效性.

  1. 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.

  2. Ocean Surface Wind Speed of Hurricane Helene Observed by SAR

    DEFF Research Database (Denmark)

    Xu, Qing; Cheng, Yongcun; Li, Xiaofeng;

    2011-01-01

    Prediction System (NOGAPS) model, C-band geophysical model functions (GMFs) which describe the normalized radar cross section (NRCS) dependence on the wind speed and the geometry of radar observations (i.e., incidence angle and azimuth angle with respect to wind direction) such as CMOD5 and newly developed...... CIWRAP models have been tested to extract wind speed from SAR data. The SAR retrieved ocean surface winds were compared to the aircraft wind speed observations from stepped frequency microwave radiometer (SFMR). The results show the capability of hurricane wind monitoring by SAR....

  3. Speeding chemical reactions by focusing

    CERN Document Server

    Lacasta, A M; Sancho, J M; Lindenberg, K

    2012-01-01

    We present numerical results for a chemical reaction of colloidal particles which are transported by a laminar fluid and are focused by periodic obstacles in such a way that the two components are well mixed and consequently the chemical reaction is speeded up. The roles of the various system parameters (diffusion coefficients, reaction rate, obstacles sizes) are studied. We show that focusing speeds up the reaction from the diffusion limited rate (t to the power -1/2) to very close to the perfect mixing rate, (t to the power -1).

  4. System Analyses of Pneumatic Technology for High Speed Civil Transport Aircraft

    Science.gov (United States)

    Mavris, Dimitri N.; Tai, Jimmy C.; Kirby, Michelle M.; Roth, Bryce A.

    1999-01-01

    The primary aspiration of this study was to objectively assess the feasibility of the application of a low speed pneumatic technology, in particular Circulation Control (CC) to an HSCT concept. Circulation Control has been chosen as an enabling technology to be applied on a generic High Speed Civil Transport (HSCT). This technology has been proven for various subsonic vehicles including flight tests on a Navy A-6 and computational application on a Boeing 737. Yet, CC has not been widely accepted for general commercial fixed-wing use but its potential has been extensively investigated for decades in wind tunnels across the globe for application to rotorcraft. More recently, an experimental investigation was performed at Georgia Tech Research Institute (GTRI) with application to an HSCT-type configuration. The data from those experiments was to be applied to a full-scale vehicle to assess the impact from a system level point of view. Hence, this study attempted to quantitatively assess the impact of this technology to an HSCT. The study objective was achieved in three primary steps: 1) Defining the need for CC technology; 2) Wind tunnel data reduction; 3) Detailed takeoff/landing performance assessment. Defining the need for the CC technology application to an HSCT encompassed a preliminary system level analysis. This was accomplished through the utilization of recent developments in modern aircraft design theory at Aerospace Systems Design Laboratory (ASDL). These developments include the creation of techniques and methods needed for the identification of technical feasibility show stoppers. These techniques and methods allow the designer to rapidly assess a design space and disciplinary metric enhancements to enlarge or improve the design space. The takeoff and landing field lengths were identified as the concept "show-stoppers". Once the need for CC was established, the actual application of data and trends was assessed. This assessment entailed a reduction of the

  5. Nonlinear dynamics approach of modeling the bifurcation for aircraft wing flutter in transonic speed

    DEFF Research Database (Denmark)

    Matsushita, Hiroshi; Miyata, T.; Christiansen, Lasse Engbo

    2002-01-01

    The procedure of obtaining the two-degrees-of-freedom, finite dimensional. nonlinear mathematical model. which models the nonlinear features of aircraft flutter in transonic speed is reported. The model enables to explain every feature of the transonic flutter data of the wind tunnel tests...... conducted at National Aerospace Laboratory in Japan for a high aspect ratio wing. It explains the nonlinear features of the transonic flutter such as the subcritical Hopf bifurcation of a limit cycle oscillation (LCO), a saddle-node bifurcation, and an unstable limit cycle as well as a normal (linear...

  6. The dynamics of the HSCT environment. [air pollution from High Speed Civil Transport Aircraft

    Science.gov (United States)

    Douglass, Anne R.; Rood, Richard B.

    1991-01-01

    Assessments of the impact of aircraft engine exhausts on stratospheric ozone levels are currently limited to 2D zonally-averaged models which, while completely representing chemistry, involve high parameterization of transport processes. Prospective 3D models under development by NASA-Goddard will use winds from a data-assimilation procedure; the upper troposphere/lower stratosphere behavior of one such model has been verified by direct comparison of model simulations with satellite, balloon, and sonde measurements. Attention is presently given to the stratosphere/troposphere exchange and nonzonal distribution of aircraft engine exhaust.

  7. 76 FR 6525 - Airworthiness Directives; Cessna Aircraft Company (Type Certificate Previously Held by Columbia...

    Science.gov (United States)

    2011-02-07

    ... Company (Type Certificate Previously Held by Columbia Aircraft Manufacturing (Previously the Lancair... Aircraft Company (Type Certificate Previously Held by Columbia Aircraft Manufacturing (Previously The... Aircraft Company (type certificate previously held by Columbia Aircraft Manufacturing (previously...

  8. NASA-UVa Light Aerospace Alloy and Structures Technology Program: Aluminum-Based Materials for High Speed Aircraft

    Science.gov (United States)

    Starke, E. A., Jr. (Editor)

    1996-01-01

    This report is concerned with 'Aluminum-Based Materials for High Speed Aircraft' which was initiated to identify the technology needs associated with advanced, low-cost aluminum base materials for use as primary structural materials. Using a reference baseline aircraft, these materials concept will be further developed and evaluated both technically and economically to determine the most attractive combinations of designs, materials, and manufacturing techniques for major structural sections of an HSCT. Once this has been accomplished, the baseline aircraft will be resized, if applicable, and performance objectives and economic evaluations made to determine aircraft operating costs. The two primary objectives of this study are: (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials, and (2) to assess these materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT.

  9. Effectiveness of Motorcycle speed controlled by speed hump

    Directory of Open Access Journals (Sweden)

    Pornsiri Urapa

    2014-09-01

    Full Text Available Speed humps are one of the traffic calming measures widely accepted to control vehicle speed in the local road. Humps standards from the western countries are designed mainly for the passenger car. This study, therefore, aims to reveal the effectiveness of speed hump to control the motorcycle speed. This study observes the free-flow speed of the riders at the total of 20 speed bumps and humps. They are 0.3-14.8 meter in width and 5-18 centimeter in height. The results reveal that the 85th percentile speeds reduce 15-65 percent when crossing the speed bumps and speed humps. Besides, this study develops the speed model to predict the motorcycle mean speed and 85th percentile speed. It is found that speed humps follow the ITE standard can control motorcycle crossing speeds to be 25-30 Kph which are suitable to travel on the local road.

  10. Additional Development and Systems Analyses of Pneumatic Technology for High Speed Civil Transport Aircraft

    Science.gov (United States)

    Englar, Robert J.; Willie, F. Scott; Lee, Warren J.

    1999-01-01

    In the Task I portion of this NASA research grant, configuration development and experimental investigations have been conducted on a series of pneumatic high-lift and control surface devices applied to a generic High Speed Civil Transport (HSCT) model configuration to determine their potential for improved aerodynamic performance, plus stability and control of higher performance aircraft. These investigations were intended to optimize pneumatic lift and drag performance; provide adequate control and longitudinal stability; reduce separation flowfields at high angle of attack; increase takeoff/climbout lift-to-drag ratios; and reduce system complexity and weight. Experimental aerodynamic evaluations were performed on a semi-span HSCT generic model with improved fuselage fineness ratio and with interchangeable plain flaps, blown flaps, pneumatic Circulation Control Wing (CCW) high-lift configurations, plain and blown canards, a novel Circulation Control (CC) cylinder blown canard, and a clean cruise wing for reference. Conventional tail power was also investigated for longitudinal trim capability. Also evaluated was unsteady pulsed blowing of the wing high-lift system to determine if reduced pulsed mass flow rates and blowing requirements could be made to yield the same lift as that resulting from steady-state blowing. Depending on the pulsing frequency applied, reduced mass flow rates were indeed found able to provide lift augmentation at lesser blowing values than for the steady conditions. Significant improvements in the aerodynamic characteristics leading to improved performance and stability/control were identified, and the various components were compared to evaluate the pneumatic potential of each. Aerodynamic results were provided to the Georgia Tech Aerospace System Design Lab. to conduct the companion system analyses and feasibility study (Task 2) of theses concepts applied to an operational advanced HSCT aircraft. Results and conclusions from these

  11. Mutual Interference of Multiple Bodies in the Flow Field of the F-4C Aircraft in the Transonic Speed Range.

    Science.gov (United States)

    1979-12-01

    incidence angles of the store longi- tudinal axis at carriage with respect to the aircraft longitudinal axis, positive nose up and nose to the right...respect to the aircraft longitudinal axes positivc forward as seen by the pilot Y P Perpendicular to the Xp direction and parallel to the XF-YF plane...yaw incidence angles of the store longitudinal axis at carriage with respect to the aircraft longitudinal axis, positive nose up and nose to the right

  12. Dust emissions created by low-level rotary-winged aircraft flight over desert surfaces

    Science.gov (United States)

    Gillies, J. A.; Etyemezian, V.; Kuhns, H.; McAlpine, J. D.; King, J.; Uppapalli, S.; Nikolich, G.; Engelbrecht, J.

    2010-03-01

    There is a dearth of information on dust emissions from sources that are unique to U.S. Department of Defense testing and training activities. Dust emissions of PM 10 and PM 2.5 from low-level rotary-winged aircraft travelling (rotor-blade ≈7 m above ground level) over two types of desert surfaces (i.e., relatively undisturbed desert pavement and disturbed desert soil surface) were characterized at the Yuma Proving Ground (Yuma, AZ) in May 2007. Fugitive emissions are created by the shear stress of the outflow of high speed air created by the rotor-blade. The strength of the emissions was observed to scale primarily as a function of forward travel speed of the aircraft. Speed affects dust emissions in two ways: 1) as speed increases, peak shear stress at the soil surface was observed to decline proportionally, and 2) as the helicopter's forward speed increases its residence time over any location on the surface diminishes, so the time the downward rotor-generated flow is acting upon that surface must also decrease. The state of the surface over which the travel occurs also affects the scale of the emissions. The disturbed desert test surface produced approximately an order of magnitude greater emission than the undisturbed surface. Based on the measured emission rates for the test aircraft and the established scaling relationships, a rotary-winged aircraft similar to the test aircraft traveling 30 km h -1 over the disturbed surface would need to travel 4 km to produce emissions equivalent to one kilometer of travel by a light wheeled military vehicle also traveling at 30 km h -1 on an unpaved road. As rotary-winged aircraft activity is substantially less than that of off-road vehicle military testing and training activities it is likely that this source is small compared to emissions created by ground-based vehicle movements.

  13. Flow rate and trajectory of water spray produced by an aircraft tire

    Science.gov (United States)

    Daugherty, Robert H.; Stubbs, Sandy M.

    1986-01-01

    One of the risks associated with wet runway aircraft operation is the ingestion of water spray produced by an aircraft's tires into its engines. This problem can be especially dangerous at or near rotation speed on the takeoff roll. An experimental investigation was conducted in the NASA Langley Research Center Hydrodynamics Research Facility to measure the flow rate and trajectory of water spray produced by an aircraft nose tire operating on a flooded runway. The effects of various parameters on the spray patterns including distance aft of nosewheel, speed, load, and water depth were evaluated. Variations in the spray pattern caused by the airflow about primary structure such as the fuselage and wing are discussed. A discussion of events in and near the tire footprint concerning spray generation is included.

  14. Force Measurement on Aircraft Model with and without Winglet using Low Speed Wind Tunnel

    Directory of Open Access Journals (Sweden)

    N.Muthusamy

    2014-12-01

    Full Text Available The objective of the research is to conduct experiment by fabricating a standard aircraft model and retrofit winglets with cant angles 0 degree (vertical,30 degree and 60 degree. The experiments were conducted in a subsonic wind tunnel of size (feet 3x4x6.The experiment was conducted both for basic model and the model modified with winglets. The model with winglet has exhibited substantial reduction of coefficient of drag. The stall characteristics of the winglet were analyzed by plotting suitable graph. A calibrated three component balance was used for measuring the forces. Automated turntable mounted in the test section of the wind tunnel and therecording systems were used efficiently. The results were compared and discussed.

  15. Thermodynamic correction of particle concentrations measured by underwing probes on fast-flying aircraft

    Science.gov (United States)

    Weigel, Ralf; Spichtinger, Peter; Mahnke, Christoph; Klingebiel, Marcus; Afchine, Armin; Petzold, Andreas; Krämer, Martina; Costa, Anja; Molleker, Sergej; Reutter, Philipp; Szakáll, Miklós; Port, Max; Grulich, Lucas; Jurkat, Tina; Minikin, Andreas; Borrmann, Stephan

    2016-10-01

    Particle concentration measurements with underwing probes on aircraft are impacted by air compression upstream of the instrument body as a function of flight velocity. In particular, for fast-flying aircraft the necessity arises to account for compression of the air sample volume. Hence, a correction procedure is needed to invert measured particle number concentrations to ambient conditions that is commonly applicable to different instruments to gain comparable results. In the compression region where the detection of particles occurs (i.e. under factual measurement conditions), pressure and temperature of the air sample are increased compared to ambient (undisturbed) conditions in certain distance away from the aircraft. Conventional procedures for scaling the measured number densities to ambient conditions presume that the air volume probed per time interval is determined by the aircraft speed (true air speed, TAS). However, particle imaging instruments equipped with pitot tubes measuring the probe air speed (PAS) of each underwing probe reveal PAS values systematically below those of the TAS. We conclude that the deviation between PAS and TAS is mainly caused by the compression of the probed air sample. From measurements during two missions in 2014 with the German Gulfstream G-550 (HALO - High Altitude LOng range) research aircraft we develop a procedure to correct the measured particle concentration to ambient conditions using a thermodynamic approach. With the provided equation, the corresponding concentration correction factor ξ is applicable to the high-frequency measurements of the underwing probes, each of which is equipped with its own air speed sensor (e.g. a pitot tube). ξ values of 1 to 0.85 are calculated for air speeds (i.e. TAS) between 60 and 250 m s-1. For different instruments at individual wing position the calculated ξ values exhibit strong consistency, which allows for a parameterisation of ξ as a function of TAS for the current HALO

  16. Measurement of Phase Difference for Micromachined Gyros Driven by Rotating Aircraft

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2013-08-01

    Full Text Available This paper presents an approach for realizing a phase difference measurement of a new gyro. A silicon micromachined gyro was mounted on rotating aircraft for aircraft attitude control. Aircraft spin drives the silicon pendulum of a gyro rotating at a high speed so that it can sense the transverse angular velocity of the rotating aircraft based on the gyroscopic precession principle when the aircraft has transverse rotation. In applications of the rotating aircraft single channel control system, such as damping in the attitude stabilization loop, the gyro signal must be kept in sync with the control signal. Therefore, the phase difference between both signals needs to be measured accurately. Considering that phase difference is mainly produced by both the micromachined part and the signal conditioning circuit, a mathematical model has been established and analyzed to determine the gyro’s phase frequency characteristics. On the basis of theoretical analysis, a dynamic simulation has been done for a case where the spin frequency is 15 Hz. Experimental results with the proposed measurement method applied to a silicon micromachined gyro driven by a rotating aircraft demonstrate that it is effective in practical applications. Measured curve and numerical analysis of phase frequency characteristic are in accordance, and the error between measurement and simulation is only 5.3%.

  17. Investigation of Load and Pressure Distribution onWing with Wake Rollup for Low Speed Aircraft

    OpenAIRE

    Laith W. Ismail

    2008-01-01

    The presented work shows a preliminary analytic method for estimation of load and pressure distributions on low speed wings with flow separation and wake rollup phenomenas. A higher order vortex panel method is coupled with the numerical lifting line theory by means of iterative procedure including models of separation and wake rollup. The computer programs are written in FORTRAN which are stable and efficient. The capability of the present method is investigated through a number of test case...

  18. Dynamic Aberration Correction for Conformal Window of High-Speed Aircraft Using Optimized Model-Based Wavefront Sensorless Adaptive Optics.

    Science.gov (United States)

    Dong, Bing; Li, Yan; Han, Xin-Li; Hu, Bin

    2016-09-02

    For high-speed aircraft, a conformal window is used to optimize the aerodynamic performance. However, the local shape of the conformal window leads to large amounts of dynamic aberrations varying with look angle. In this paper, deformable mirror (DM) and model-based wavefront sensorless adaptive optics (WSLAO) are used for dynamic aberration correction of an infrared remote sensor equipped with a conformal window and scanning mirror. In model-based WSLAO, aberration is captured using Lukosz mode, and we use the low spatial frequency content of the image spectral density as the metric function. Simulations show that aberrations induced by the conformal window are dominated by some low-order Lukosz modes. To optimize the dynamic correction, we can only correct dominant Lukosz modes and the image size can be minimized to reduce the time required to compute the metric function. In our experiment, a 37-channel DM is used to mimic the dynamic aberration of conformal window with scanning rate of 10 degrees per second. A 52-channel DM is used for correction. For a 128 × 128 image, the mean value of image sharpness during dynamic correction is 1.436 × 10(-5) in optimized correction and is 1.427 × 10(-5) in un-optimized correction. We also demonstrated that model-based WSLAO can achieve convergence two times faster than traditional stochastic parallel gradient descent (SPGD) method.

  19. Dynamic Aberration Correction for Conformal Window of High-Speed Aircraft Using Optimized Model-Based Wavefront Sensorless Adaptive Optics

    Science.gov (United States)

    Dong, Bing; Li, Yan; Han, Xin-li; Hu, Bin

    2016-01-01

    For high-speed aircraft, a conformal window is used to optimize the aerodynamic performance. However, the local shape of the conformal window leads to large amounts of dynamic aberrations varying with look angle. In this paper, deformable mirror (DM) and model-based wavefront sensorless adaptive optics (WSLAO) are used for dynamic aberration correction of an infrared remote sensor equipped with a conformal window and scanning mirror. In model-based WSLAO, aberration is captured using Lukosz mode, and we use the low spatial frequency content of the image spectral density as the metric function. Simulations show that aberrations induced by the conformal window are dominated by some low-order Lukosz modes. To optimize the dynamic correction, we can only correct dominant Lukosz modes and the image size can be minimized to reduce the time required to compute the metric function. In our experiment, a 37-channel DM is used to mimic the dynamic aberration of conformal window with scanning rate of 10 degrees per second. A 52-channel DM is used for correction. For a 128 × 128 image, the mean value of image sharpness during dynamic correction is 1.436 × 10−5 in optimized correction and is 1.427 × 10−5 in un-optimized correction. We also demonstrated that model-based WSLAO can achieve convergence two times faster than traditional stochastic parallel gradient descent (SPGD) method. PMID:27598161

  20. Open Rotor Noise Shielding by Blended-Wing-Body Aircraft

    Science.gov (United States)

    Guo, Yueping; Czech, Michael J.; Thomas, Russell H.

    2015-01-01

    This paper presents an analysis of open rotor noise shielding by Blended Wing Body (BWB) aircraft by using model scale test data acquired in the Boeing Low Speed Aeroacoustic Facility (LSAF) with a legacy F7/A7 rotor model and a simplified BWB platform. The objective of the analysis is the understanding of the shielding features of the BWB and the method of application of the shielding data for noise studies of BWB aircraft with open rotor propulsion. By studying the directivity patterns of individual tones, it is shown that though the tonal energy distribution and the spectral content of the wind tunnel test model, and thus its total noise, may differ from those of more advanced rotor designs, the individual tones follow directivity patterns that characterize far field radiations of modern open rotors, ensuring the validity of the use of this shielding data. Thus, open rotor tonal noise shielding should be categorized into front rotor tones, aft rotor tones and interaction tones, not only because of the different directivities of the three groups of tones, but also due to the differences in their source locations and coherence features, which make the respective shielding characteristics of the three groups of tones distinctly different from each other. To reveal the parametric trends of the BWB shielding effects, results are presented with variations in frequency, far field emission angle, rotor operational condition, engine installation geometry, and local airframe features. These results prepare the way for the development of parametric models for the shielding effects in prediction tools.

  1. Aircraft propeller control

    Science.gov (United States)

    Day, Stanley G. (Inventor)

    1990-01-01

    In the invention, the speeds of both propellers in a counterrotating aircraft propeller pair are measured. Each speed is compared, using a feedback loop, with a demanded speed and, if actual speed does not equal demanded speed for either propeller, pitch of the proper propeller is changed in order to attain the demanded speed. A proportional/integral controller is used in the feedback loop. Further, phase of the propellers is measured and, if the phase does not equal a demanded phase, the speed of one propeller is changed, by changing pitch, until the proper phase is attained.

  2. Three dimensional model calculations of the global dispersion of high speed aircraft exhaust and implications for stratospheric ozone loss

    Science.gov (United States)

    Douglass, Anne R.; Rood, Richard B.; Jackman, Charles H.; Weaver, Clark J.

    1994-01-01

    Two-dimensional (zonally averaged) photochemical models are commonly used for calculations of ozone changes due to various perturbations. These include calculating the ozone change expected as a result of change in the lower stratospheric composition due to the exhaust of a fleet of supersonic aircraft flying in the lower stratosphere. However, zonal asymmetries are anticipated to be important to this sort of calculation. The aircraft are expected to be restricted from flying over land at supersonic speed due to sonic booms, thus the pollutant source will not be zonally symmetric. There is loss of pollutant through stratosphere/troposphere exchange, but these processes are spatially and temporally inhomogeneous. Asymmetry in the pollutant distribution contributes to the uncertainty in the ozone changes calculated with two dimensional models. Pollutant distributions for integrations of at least 1 year of continuous pollutant emissions along flight corridors are calculated using a three dimensional chemistry and transport model. These distributions indicate the importance of asymmetry in the pollutant distributions to evaluation of the impact of stratospheric aircraft on ozone. The implications of such pollutant asymmetries to assessment calculations are discussed, considering both homogeneous and heterogeneous reactions.

  3. NASA-UVA Light Aerospace Alloy and Structure Technology Program Supplement: Aluminum-Based Materials for High Speed Aircraft

    Science.gov (United States)

    Starke, E. A., Jr.

    1997-01-01

    This is the final report of the study "Aluminum-Based Materials for High Speed Aircraft" which had the objectives (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials and (2) to assess the materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT. The research team consisted of ALCOA, Allied-Signal, Boeing, McDonnell Douglas, Reynolds Metals and the University of Virginia. Four classes of aluminum alloys were investigated: (1) I/M 2XXX containing Li and I/M 2XXX without Li, (2) I/M 6XXX, (3) two P/M 2XXX alloys, and (4) two different aluminum-based metal matrix composites (MMC). The I/M alloys were targeted for a Mach 2.0 aircraft and the P/M and MMC alloys were targeted for a Mach 2.4 aircraft. Design studies were conducted using several different concepts including skin/stiffener (baseline), honeycomb sandwich, integrally stiffened and hybrid adaptations (conventionally stiffened thin-sandwich skins). Alloy development included fundamental studies of coarsening behavior, the effect of stress on nucleation and growth of precipitates, and fracture toughness as a function of temperature were an integral part of this program. The details of all phases of the research are described in this final report.

  4. Exploratory flight investigation of aircraft response to the wing vortex wake generated by the augmentor wing jet STOL research aircraft

    Science.gov (United States)

    Jacobsen, R. A.; Drinkwater, F. J., III

    1975-01-01

    A brief exploratory flight program was conducted at Ames Research Center to investigate the vortex wake hazard of a powered-lift STOL aircraft. The study was made by flying an instrumented Cessna 210 aircraft into the wake of the augmentor wing jet STOL research aircraft at separation distances from 1 to 4 n.mi. Characteristics of the wake were evaluated in terms of the magnitude of the upset of the probing aircraft. Results indicated that within 1 n.mi. separation the wake could cause rolling moments in excess of roll control power and yawing moments equivalent to rudder control power of the probe aircraft. Subjective evaluations by the pilots of the Cessna 210 aircraft, supported by response measurements, indicated that the upset caused by the wake of the STOL aircraft was comparable to that of a DC-9 in the landing configuration.

  5. Mode Transition Variable Geometry for High Speed Inlets for Hypersonic Aircraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hypersonic propulsion research has been a focus of the NASA aeronautics program for years. Previous high-speed cruise and space access programs have examined the...

  6. Investigation of Load and Pressure Distribution onWing with Wake Rollup for Low Speed Aircraft

    Directory of Open Access Journals (Sweden)

    Laith W. Ismail

    2008-01-01

    Full Text Available The presented work shows a preliminary analytic method for estimation of load and pressure distributions on low speed wings with flow separation and wake rollup phenomena’s. A higher order vortex panel method is coupled with the numerical lifting line theory by means of iterative procedure including models of separation and wake rollup. The computer programs are written in FORTRAN which are stable and efficient. The capability of the present method is investigated through a number of test cases with different types of wing sections (NACA 0012 and GA(W-1 for different aspect ratios and angles of attack, the results include the lift and drag curves, lift and pressure distributions along the wing span taking into the consideration the effect of the angles of attack and the aspect ratios on the wake rollup. The pressure distribution on the wings shows that there is a region of constant pressure on the upper surface of the wings near the trailing edge in the middle of the wing, also there is a region of flow separation on the upper surface of the wings. A good agreement is found between the presented work results and other from previous researches. These results show that the presented method is able to capture much of flow over wings feature like separation and wake rollup.

  7. Improving homogeneity by dynamic speed limit systems.

    NARCIS (Netherlands)

    Nes, N. van Brandenberg, S. & Twisk, D.A.M.

    2010-01-01

    Homogeneity of driving speeds is an important variable in determining road safety; more homogeneous driving speeds increase road safety. This study investigates the effect of introducing dynamic speed limit systems on homogeneity of driving speeds. A total of 46 subjects twice drove a route along 12

  8. Modern trends of aircraft fly-by-wire systems

    Directory of Open Access Journals (Sweden)

    С. С. Юцкевич

    2013-07-01

    Full Text Available Specifics of civil aviation modern transport aircraft fly-by-wire control systems are described. A comparison of the systems-level hardware and software, expressed through modes of guidance, provision of aircraft Airbus A-320, Boeing B-777, Tupolev Tu-214, Sukhoi Superjet SSJ-100 are carried out. The possibility of transition from mechanical control wiring to control through fly-by-wire system in the backup channel is shown.

  9. AERODYNAMIC BEHAVIOR AIRCRAFT CAUSED BY RESIDUAL STRAIN WINGS

    Directory of Open Access Journals (Sweden)

    Sergiy Ishchenko

    2011-03-01

    Full Text Available Abstract. The influence of residual strain on the airframe aerodynamic characteristics of aircraft wasconsidered. The possibility of estimation of changes in deformation of airframe using data of leveling wasshown. The method of estimating the change of aerodynamic characteristics caused by the influence ofresidual strain airframe was proposed. Technique can be used in the operation and overhaul of aircraft withlarge operating time.Keywords: aerodynamic characteristics, residual strain construction asymmetric moments, thedistribution of circulation, the scheme of leveling, trigonometric series.

  10. AERODYNAMIC BEHAVIOR AIRCRAFT CAUSED BY RESIDUAL STRAIN WINGS

    OpenAIRE

    Ishchenko, Sergiy; Tofil, Arkadiush

    2011-01-01

    Abstract. The influence of residual strain on the airframe aerodynamic characteristics of aircraft wasconsidered. The possibility of estimation of changes in deformation of airframe using data of leveling wasshown. The method of estimating the change of aerodynamic characteristics caused by the influence ofresidual strain airframe was proposed. Technique can be used in the operation and overhaul of aircraft withlarge operating time.Keywords: aerodynamic characteristics, residual strain constr...

  11. A comparison of aircraft tire skid with initial wheel\\ud rotational speed using ANSYS transient simulation

    OpenAIRE

    Alroqi, Abdurrhman A; Wang, Weiji

    2016-01-01

    Based on heavy aircraft main landing gear tires touchdown skidding process, patents have been registered since the 1940s to improve tire safety, decrease the substantial wear and smoke that results from every landing by spinning the rear wheels before touchdown. A single wheel has been modeled as a mass-spring-damper system using ANSYS mechanical transient simulation to analyze static and pre-rotating wheels behavior during a short period between touchdown and skidding, to spin-up to reach th...

  12. 3D pressure imaging of an aircraft propeller blade-tip flow by phase-locked stereoscopic PIV

    NARCIS (Netherlands)

    Ragni, D.; Van Oudheusden, B.W.; Scarano, F.

    2011-01-01

    The flow field at the tip region of a scaled DHC Beaver aircraft propeller, running at transonic speed, has been investigated by means of a multi-plane stereoscopic particle image velocimetry setup. Velocity fields, phase-locked with the blade rotational motion, are acquired across several planes pe

  13. Cornering characteristics of a 40 by 14-16 type 7 aircraft tire and a comparison with characteristics of a C40 by 14-21 cantilever aircraft tire

    Science.gov (United States)

    Tanner, J. A.; Dreher, R. C.

    1973-01-01

    An investigation was conducted at the Langley aircraft landing loads and traction facility to determine the cornering characteristics of a 40 x 14-16 type VII aircraft tire. These characteristics, which include the cornering-force and drag-force friction coefficients and self-alining torque, were obtained for the tire operating on dry, damp and flooded runway surfaces over a range of yaw angles from 0 deg to 20 deg and at ground speeds from 5 to 100 knots, both with and without braking. The results of this investigation indicated that the cornering capability of the 40 x 14-16 type VII aircraft tire is degraded by high ground speeds, thin-film lubrication and tire hydroplaning effects on the wet surfaces, and brake torque. The cornering capability is greatly diminished when locked-wheel skids are encountered.

  14. Fuel-rich, catalytic reaction experimental results. [fuel development for high-speed civil transport aircraft

    Science.gov (United States)

    Rollbuhler, Jim

    1991-01-01

    Future aeropropulsion gas turbine combustion requirements call for operating at very high inlet temperatures, pressures, and large temperature rises. At the same time, the combustion process is to have minimum pollution effects on the environment. Aircraft gas turbine engines utilize liquid hydrocarbon fuels which are difficult to uniformly atomize and mix with combustion air. An approach for minimizing fuel related problems is to transform the liquid fuel into gaseous form prior to the completion of the combustion process. Experimentally obtained results are presented for vaporizing and partially oxidizing a liquid hydrocarbon fuel into burnable gaseous components. The presented experimental data show that 1200 to 1300 K reaction product gas, rich in hydrogen, carbon monoxide, and light-end hydrocarbons, is formed when flowing 0.3 to 0.6 fuel to air mixes through a catalyst reactor. The reaction temperatures are kept low enough that nitrogen oxides and carbon particles (soot) do not form. Results are reported for tests using different catalyst types and configurations, mass flowrates, input temperatures, and fuel to air ratios.

  15. Measurement and prediction of propeller flow field on the PTA aircraft at speeds of up to Mach 0.85. [Propfan Test Assessment

    Science.gov (United States)

    Aljabri, Abdullah S.

    1988-01-01

    High speed subsonic transports powered by advanced propellers provide significant fuel savings compared to turbofan powered transports. Unfortunately, however, propfans must operate in aircraft-induced nonuniform flow fields which can lead to high blade cyclic stresses, vibration and noise. To optimize the design and installation of these advanced propellers, therefore, detailed knowledge of the complex flow field is required. As part of the NASA Propfan Test Assessment (PTA) program, a 1/9 scale semispan model of the Gulfstream II propfan test-bed aircraft was tested in the NASA-Lewis 8 x 6 supersonic wind tunnel to obtain propeller flow field data. Detailed radial and azimuthal surveys were made to obtain the total pressure in the flow and the three components of velocity. Data was acquired for Mach numbers ranging from 0.6 to 0.85. Analytical predictions were also made using a subsonic panel method, QUADPAN. Comparison of wind-tunnel measurements and analytical predictions show good agreement throughout the Mach range.

  16. Interference Cancellation in Aircraft Cockpit by Adaptive Filters

    Directory of Open Access Journals (Sweden)

    Arun C.

    2016-01-01

    Full Text Available This paper investigates on the development and implementation of adaptive noise cancellation (ANC algorithm meant for mitigating the high level engine noise in the cockpit of an aircraft, which makes the speech signal unintelligible. Adaptive filters configured as interference canceller have the potential application in mitigating the above interference. A comparative study of Gradient based adaptive Infinite Impulse Response (IIR algorithm and its modified version is performed using MATLAB simulator in terms of converging speed. From the simulation result the best IIR algorithm is used for implementation in Performance Optimized with Enhanced RISC PC (Power PC 7448.

  17. In-flight measurements of aircraft propeller deformation by means of an autarkic fast rotating imaging system

    Science.gov (United States)

    Stasicki, Boleslaw; Boden, Fritz

    2015-03-01

    The non-intrusive in-flight measurement of the deformation and pitch of the aircraft propeller is a demanding task. The idea of an imaging system integrated and rotating with the aircraft propeller has been presented on the 30th International Congress on High-Speed Imaging and Photonics (ICHSIP30) in 2012. Since then this system has been constructed and tested in the laboratory as well as on the real aircraft. In this paper we outline the principle of Image Pattern Correlation Technique (IPCT) based on Digital Image Correlation (DIC) and describe the construction of a dedicated autarkic 3D camera system placed on the investigated propeller and rotating at its full speed. Furthermore, the results of the first ground and in-flight tests are shown and discussed. This development has been found by the European Commission within the 7th frame project AIM2 (contract no. 266107).

  18. High-resolution wind and temperature observations from aircraft tracked by Mode-S air traffic control radar

    Science.gov (United States)

    de Haan, S.

    2011-05-01

    Wind, temperature, and humidity observations from radiosonde and aircraft are the main sources of upper air information for meteorology. For mesoscale meteorology, the horizontal coverage of radiosondes is too sparse. Aircraft observations through Aircraft Meteorological Data Relay (AMDAR) sample an atmospheric profile in the vicinity of airports. However, not all aircraft are equipped with AMDAR or have the system activated. Observations inferred from an enhanced tracking and ranging (TAR) air traffic control radar can fill this gap. These radars follows all aircraft in the airspace visible to the radar for air traffic management. The TAR radar at Schiphol airport in Netherlands has a range of 270 km. This Mode-S radar contacts each aircraft every 4 s on which the transponder in the aircraft responds with a message that contains information on flight level, direction, and speed. Combined with the ground track of an aircraft, meteorological information on temperature and wind can be inferred from this information. Because all aircraft are required to respond to the TAR radar, the data volume is extremely large, being around 1.5 million observations per day. Note that there are no extra costs for this data link. The quality of these observations is assessed by comparison to numerical weather prediction (NWP) model information, AMDAR observations, and radiosonde observations. A preprocessing step is applied to enhance the quality of wind and temperature observations, albeit with a reduced time frequency of one observation of horizontal wind vector and temperature per aircraft per minute. Nevertheless, the number of observations per day is still very large. In this paper it is shown that temperature observations from Mode-S, even after corrections, are not very good; an RMS which is twice as large as AMDAR is observed when compared to NWP. In contrast to the temperature observations, the quality found for wind after correction and calibration is good; it is comparable

  19. Noise Generation by Fans with Supersonic Tip Speeds

    Science.gov (United States)

    Glegg, Stewart; Envia, Edmane (Technical Monitor)

    2003-01-01

    Fan noise continues to be a significant issue for commercial aircraft engines and there still exists a requirement for improved understanding of the fundamental issues associated with fan noise source mechanisms. At the present time, most of the prediction methods identify the dominant acoustic sources to be associated with the stator vanes or blade trailing edges which are downstream of the fan face. However recent studies have shown that acoustic waves are significantly attenuated as they propagate upstream through a rotor, and if the appropriate corrections are applied, sound radiation from the engine inlet is significantly underpredicted. The prediction models can only be applied to fans with subsonic tip speeds. In contrast, most aircraft engines have fan tip speeds which are transonic and this implies an even higher attenuation for upstream propagating acoustic waves. Consequently understanding how sound propagates upstream through the fan is an important, and not well understood phenomena. The objective of this study is to provide improved insight into the upstream propagation effects through a rotor which are relevant to full scale engines. The focus of this study is on broadband fan noise generated by boundary layer turbulence interacting with the trailing edges of the fan blades. If this source mechanism is important upstream of the fan, the sound must propagate upstream through a transonic non uniform flow which includes large gradients and non linearities. Developing acoustic propagation models in this type of flow is challenging and currently limited to low frequency applications, where the frequency is of the same order as the blade passing frequency of the fan. For trailing edge noise, much higher frequencies are relevant and so a suitable approach needs to be developed, which is not limited by an unacceptably large computational effort. In this study we are in the process of developing a computational method which applies for the high frequencies of

  20. Annoyance by aircraft noise and fear of overflying aircraft in relation to attitudes toward the environment and community

    Science.gov (United States)

    Loeb, M.; Moran, S. V.

    1977-01-01

    It has been suggested that expressions of annoyance attributable to aircraft noise may reflect in part fear of aircraft overflights and possible crashes. If this is true, then residents of areas where crashes have occurred should express more annoyance. To test this hypothesis, 50 residents of an Albany, New York area where an aircraft crash producing fatalities recently occurred and 50 residents of a comparable nearby area without such a history, were asked to respond to a 'Quality of Life Questionnaire.' Among the items were some designed to test annoyance by noise and fear of aircraft overflights. It was predicted that those in the crash area would express more fear and would more often identify aircraft as a noise source. These hypotheses were sustained. A near-replication was carried out in Louisville, Kentucky; results were much the same. Analyses indicated that for the crash-area groups, there was associating of aircraft fear and noise annoyance responses; this was true to an apparently lesser extent for non-crash groups. The greater annoyance of crash groups by aircraft community noise apparently does not carry over to situations in which aircraft noise is assessed in the laboratory.

  1. Near-field commercial aircraft contribution to nitrogen oxides by engine, aircraft type, and airline by individual plume sampling.

    Science.gov (United States)

    Carslaw, David C; Ropkins, Karl; Laxen, Duncan; Moorcroft, Stephen; Marner, Ben; Williams, Martin L

    2008-03-15

    Nitrogen oxides (NOx) concentrations were measured in individual plumes from aircraft departing on the northern runway at Heathrow Airport in west London. Over a period of four weeks 5618 individual plumes were sampled by a chemiluminescence monitor located 180 m from the runway. Results were processed and matched with detailed aircraft movement and aircraft engine data using chromatographic techniques. Peak concentrations associated with 29 commonly used engines were calculated and found to have a good relationship with N0x emissions taken from the International Civil Aviation Organization (ICAO) databank. However, it is found that engines with higher reported NOx emissions result in proportionately lower NOx concentrations than engines with lower emissions. We show that it is likely that aircraft operational factors such as takeoff weight and aircraftthrust setting have a measurable and important effect on concentrations of N0x. For example, NOx concentrations can differ by up to 41% for aircraft using the same airframe and engine type, while those due to the same engine type in different airframes can differ by 28%. These differences are as great as, if not greater than, the reported differences in NOx emissions between different engine manufacturers for engines used on the same airframe.

  2. Advances on Propulsion Technology for High-Speed Aircraft. Volume 1

    Science.gov (United States)

    2007-03-01

    and non- intrusive optical approaches. Much of the information of interest 11 I I must be deduced from measurements which are sensitive to competing...physical vapour deposition (EB-PVD), vacuum plasma spraying (VPS) and solution plasma spraying (SPS) [38-41]. A segmented sub-scale model combustor with...advantage of the existing alumina pebble bed heater which allows to perform test with air non vitiated by water vapour up to Mach 6.5 conditions (1800

  3. Climate Based Performance of Carbon-Carbon Disc Brake for High Speed Aircraft Braking System

    Directory of Open Access Journals (Sweden)

    R. M. Mohanty

    2013-09-01

    Full Text Available Carbon composite brake discs are lighter, economical, and have excellent high energy friction characteristics. These have twice thermal capability compared to steel, remain unaffected by thermal shocks and mechanical fatigue. These are highly useful in emergency breaking situations. Prior to this work, two dimensional (2D reinforced carbon composite laminates were prepared through pitch impregnation process. In an effort to protect the exposed non frictional surface from high temperature service degradations, multilayered ceramic coating systems were developed on 2D composite. Oxidation studies have been carried out on these systems viz., C-SiC, C-SiC-MoSi2-Al2O3 and C-SiC-B4C. These were performed both in dynamic and static conditions up to 1200 °C in 60 per cent humid climate. The hardness, surface topography, developed phases and integrity of layers on the samples at various stages of the experiment have been characterized and analyzed. It was observed that C-SiC-B4C system performs well in the oxidizing environment.Defence Science Journal, 2013, 63(5, pp.531-538, DOI:http://dx.doi.org/10.14429/dsj.63.3932

  4. 9- by 15-Foot Low Speed Wind Tunnel Acoustic Improvements Expanded Overview

    Science.gov (United States)

    Stephens, David

    2016-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) at NASA Glenn Research Center was built in 1969 in the return leg of the 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT). The 8x6 SWT was completed in 1949 and acoustically treated to mitigate community noise issues in 1950. This treatment included the addition of a large muffler downstream of the 8x6 SWT test section and diffuser. The 9x15 LSWT was designed for performance testing of V/STOL aircraft models, but with the addition of the current acoustic treatment in 1986 the tunnel been used principally for acoustic and performance testing of aircraft propulsion systems. The present document describes an anticipated acoustic upgrade to be completed in 2017.

  5. Wind Speed Measurement by Paper Anemometer

    Science.gov (United States)

    Zhong, Juhua; Cheng, Zhongqi; Guan, Wenchuan

    2011-01-01

    A simple wind speed measurement device, a paper anemometer, is fabricated based on the theory of standing waves. In providing the working profile of the paper anemometer, an experimental device is established, which consists of an anemometer sensor, a sound sensor, a microphone, paper strips, a paper cup, and sonic acquisition software. It shows…

  6. 77 FR 14316 - Airworthiness Directives; Piper Aircraft, Inc. (Type Certificate Previously Held by The New Piper...

    Science.gov (United States)

    2012-03-09

    .... (Type Certificate Previously Held by The New Piper Aircraft Inc.) Airplanes AGENCY: Federal Aviation... previously held by The New Piper Aircraft Inc.) Models PA-31T and PA- 31T1 airplanes. The existing AD... the Federal Register for certain Piper Aircraft, Inc. (type certificate previously held by The...

  7. Radiative forcing from particle emissions by future supersonic aircraft

    Directory of Open Access Journals (Sweden)

    G. Pitari

    2008-07-01

    Full Text Available In this work we focus on the direct radiative forcing (RF of black carbon (BC and sulphuric acid particles emitted by future supersonic aircraft, as well as on the ozone RF due to changes produced by emissions of both gas species (NOx, H2O and aerosol particles capable of affecting stratospheric ozone chemistry. Heterogeneous chemical reactions on the surface of sulphuric acid stratospheric particles (SSA-SAD are the main link between ozone chemistry and supersonic aircraft emissions of sulphur precursors (SO2 and particles (H2O–H2SO4. Photochemical O3 changes are compared from four independent 3-D atmosphere-chemistry models (ACMs, using as input the perturbation of SSA-SAD calculated in the University of L'Aquila model, which includes on-line a microphysics code for aerosol formation and growth. The ACMs in this study use aircraft emission scenarios for the year 2050 developed by AIRBUS as a part of the EU project SCENIC, assessing options for fleet size, engine technology (NOx emission index, Mach number, range and cruising altitude. From our baseline modeling simulation, the impact of supersonic aircraft on sulphuric acid aerosol and BC mass burdens is 53 and 1.5 μg/m2, respectively, with a direct RF of −11.4 and 4.6 mW/m2 (net RF=−6.8 mW/m2. This paper discusses the similarities and differences amongst the participating models in terms of changes to O3 precursors due to aircraft emissions (NOx, HOx,Clx,Brx and the stratospheric ozone sensitivity to them. In the baseline case, the calculated global ozone change is −0.4 ±0.3 DU, with a net radiative forcing (IR+UV of −2.5± 2 mW/m2. The fraction of this O3-RF attributable to SSA-SAD changes is, however, highly variable among the models, depending on the NOx removal

  8. Relation between repeatability and speed of robot-based systems for composite aircraft production through multilateration sensor system

    Science.gov (United States)

    Bock, M.; Perner, M.; Krombholz, C.; Beykirch, B.

    2015-03-01

    Fiber composites are becoming increasingly important in different fields of lightweight application. To guarantee the estimated demand of components made of carbon fiber reinforced plastics the use of industrial robots is suggested in production. High velocity of the layup process is addressed to significantly increase the production rate. Today, the layup of the fiber material is performed by gantry systems. They are heavy weight, slow and the variety of possible part shapes is limited. Articulated robots offer a huge operational area in relation to their construction size. Moreover, they are flexible enough to layup fiber material into different shaped molds. Thus, standard articulated robots are less accurate and more susceptible to vibration than gantry systems. Therefore, this paper illustrates an approach to classify volumetric errors to obtain a relation between the achievable speed in production and precision. The prediction of a precision at a defined speed is the result. Based on the measurement results the repeatability of the robotic unit within the workspace is calculated and presented. At the minimum speed that is applicable in production the repeatability is less than 30 mm. Subsequently, an online strategy for path error compensation is presented. The approach uses a multilateration system that consists of four laser tracer units and measures the current absolute position of a reflector mounted at the end-effector of the robot. By calculating the deviation between the planned and the actual position a compensated motion is applied. The paper concludes with a discussion for further investigations.

  9. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    Directory of Open Access Journals (Sweden)

    Yanting Hu

    2013-07-01

    Full Text Available Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG developed in the simulation tool of PSCAD/EMTDC. Flicker emission of this system is investigated. The 3p (three times per revolution power oscillation due to wind shear and tower shadow effects is the significant part in the flicker emission of variable speed wind turbines with PMSG during continuous operation. A new method of flicker mitigation by controlling the rotational speed is proposed. It smoothes the 3p active power oscillations from wind shear and tower shadow effects of the wind turbine by varying the rotational speed of the PMSG. Simulation results show that damping the 3p active power oscillation by using the flicker mitigation speed controller is an effective means for flicker mitigation of variable speed wind turbines with full-scale back-to-back power converters and PMSG during continuous operation.

  10. The Acoustic Environment of the NASA Glenn 9- by 15-foot Low-Speed Wind Tunnel

    Science.gov (United States)

    Stephens, David B.

    2015-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel is an acoustic testing facility with a long history of aircraft propulsion noise research. Due to interest in renovating the facility to support future testing of advanced quiet engine designs, a study was conducted to document the background noise level in the facility and investigate the sources of contaminating noise. The anechoic quality of the facility was also investigated using an interrupted noise method. The present report discusses these aspects of the noise environment in this facility.

  11. 75 FR 82329 - Airworthiness Directives; Piper Aircraft, Inc. (Type Certificate Previously Held by The New Piper...

    Science.gov (United States)

    2010-12-30

    ... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Piper Aircraft, Inc. (Type Certificate Previously Held by The New Piper Aircraft, Inc.) Models PA-46-310P, PA- 46-350P, and... certain Piper Aircraft, Inc. Models PA-46-310P and PA-46-350P airplanes that are equipped with a Lewis...

  12. NASA-UVA Light Aerospace Alloy and Structure Technology Program Supplement: Aluminum-Based Materials for High Speed Aircraft. Final report, 1 December 1991-31 March 1996

    Energy Technology Data Exchange (ETDEWEB)

    Starke, E.A. Jr.

    1996-05-01

    This is the final report of the study `Aluminum-Based Materials for high Speed Aircraft` which had the objectives (1) to identify the most promising aluminum-based materials with respect to major structural use on the HSCT and to further develop those materials and (2) to assess the materials through detailed trade and evaluation studies with respect to their structural efficiency on the HSCT. The research team consisted of ALCOA, Allied-Signal, Boeing, McDonnell Douglas, Reynolds Metals and the University of Virginia. Four classes of aluminum alloys were investigated: (1) I/M 2XXX containing Li and I/M 2XXX with Li, (2) I/M 6XXX, (3) two P/M 2XXX alloys and (4) two different aluminum-based metal matrix composites (MMC). The I/M alloys were targeted for a Mach 2.0 aircraft and the P/M and MMC alloys were targeted for a Mach 2.4 aircraft. Design studies were conducted using several different concepts including skin/stiffener (baseline), honeycomb sandwich, integrally stiffened and hybrid adaptations (conventionally stiffened thin-sandwich skins). Alloy development included fundamental studies of coarsening behavior, the effect of stress on nucleation and growth of precipitates, and fracture toughness as a function of temperature were an integral part of this program. The details of all phases of the research are described in this final report.

  13. Induction Motor Speed Estimation by Using Spectral Current Analysis

    OpenAIRE

    2009-01-01

    An interesting application for the FFT analysis is related to the induction motor speed estimation based on spectral current analysis. The paper presents the possibility of induction motor speed estimation by using the current harmonics generated because of the rotor slots and of the eccentricity.

  14. Intensive probing of clear air convective fields by radar and instrumented drone aircraft.

    Science.gov (United States)

    Rowland, J. R.

    1972-01-01

    Clear air convective fields were probed in three summer experiments (1969, 1970, and 1971) on an S-band monopulse tracking radar at Wallops Island, Virginia, and a drone aircraft with a takeoff weight of 5.2 kg, wingspan of 2.5 m, and cruising glide speed of 10.3 m/sec. The drone was flown 23.2 km north of the radar and carried temperature, pressure/altitude, humidity, and vertical and airspeed velocity sensors. Extensive time-space convective field data were obtained by taking a large number of RHI and PPI pictures at short intervals of time. The rapidly changing overall convective field data obtained from the radar could be related to the meteorological information telemetered from the drone at a reasonably low cost by this combined technique.

  15. Improvement on Transportation Safety on Bus by Installing A Speed Limiter in Conventional Engine to Reduce Speed Rate

    Directory of Open Access Journals (Sweden)

    Pranoto Hadi

    2016-01-01

    Full Text Available Driving is one of the conditions when the driver should be given special attention to make the motor vehicle in driving way and the driver should be in a good condition. However, the problem is in a certain condition the driver lost their control speed due to their target and minimize the driving time and it led the high potential to accident. Therefore, speed limiter which applied in the bus is urgently needed to reduce the accident and improve their awareness of road safety. Developed speed limiter is completed by fuel cut-off system to prevent the engine and maintain the speed. Limitation of speed be adapted by government regulation. From the results show that the highest and average speed of 136 km/h and 123.5 km/h is observed by bus speed prior to use speed limiter. After speed limiter applied in the bus, the approved maximum speed is 90 km/h. Those data approve that the speed limiter can reduce 83% from the top speed before speed limiter applied.

  16. Effects of vehicle speed on flight initiation by Turkey vultures: implications for bird-vehicle collisions.

    Directory of Open Access Journals (Sweden)

    Travis L DeVault

    Full Text Available The avoidance of motorized vehicles is a common challenge for birds in the modern world. Birds appear to rely on antipredator behaviors to avoid vehicles, but modern vehicles (automobiles and aircraft are faster than natural predators. Thus, birds may be relatively ill-equipped, in terms of sensory capabilities and behaviors, to avoid vehicles. We examined the idea that birds may be unable to accurately assess particularly high speeds of approaching vehicles, which could contribute to miscalculations in avoidance behaviors and ultimately cause collisions. We baited turkey vultures (Cathartes aura to roads with animal carcasses and measured flight initiation distance and effective time-to-collision in response to a truck driving directly towards vultures from a starting distance of 1.13 km and at one of three speeds: 30, 60, or 90 kph (no vultures were struck. Flight initiation distance of vultures increased by a factor of 1.85 as speed increased from 30 to 90 kph. However, for 90-kph approaches there was no clear trend in flight initiation distance across replicates: birds appeared equally likely to initiate escape behavior at 40 m as at 220 m. Time-to-collision decreased by a factor of 0.62 with approach speeds from 30 to 90 kph. Also, at 90 kph, four vehicle approaches (17% resulted in near collisions with vultures (time-to-collision ≤ 1.7 s, compared to none during 60 kph approaches and one during 30 kph approaches (4%. Our findings suggest that antipredator behaviors in turkey vultures, particularly stimulus processing and response, might not be well tuned to vehicles approaching at speeds ≥ 90 kph. The possible inability of turkey vultures to react appropriately to high-speed vehicles could be common among birds, and might represent an important determinant of bird-vehicle collisions.

  17. Effects of vehicle speed on flight initiation by Turkey vultures: implications for bird-vehicle collisions.

    Science.gov (United States)

    DeVault, Travis L; Blackwell, Bradley F; Seamans, Thomas W; Lima, Steven L; Fernández-Juricic, Esteban

    2014-01-01

    The avoidance of motorized vehicles is a common challenge for birds in the modern world. Birds appear to rely on antipredator behaviors to avoid vehicles, but modern vehicles (automobiles and aircraft) are faster than natural predators. Thus, birds may be relatively ill-equipped, in terms of sensory capabilities and behaviors, to avoid vehicles. We examined the idea that birds may be unable to accurately assess particularly high speeds of approaching vehicles, which could contribute to miscalculations in avoidance behaviors and ultimately cause collisions. We baited turkey vultures (Cathartes aura) to roads with animal carcasses and measured flight initiation distance and effective time-to-collision in response to a truck driving directly towards vultures from a starting distance of 1.13 km and at one of three speeds: 30, 60, or 90 kph (no vultures were struck). Flight initiation distance of vultures increased by a factor of 1.85 as speed increased from 30 to 90 kph. However, for 90-kph approaches there was no clear trend in flight initiation distance across replicates: birds appeared equally likely to initiate escape behavior at 40 m as at 220 m. Time-to-collision decreased by a factor of 0.62 with approach speeds from 30 to 90 kph. Also, at 90 kph, four vehicle approaches (17%) resulted in near collisions with vultures (time-to-collision ≤ 1.7 s), compared to none during 60 kph approaches and one during 30 kph approaches (4%). Our findings suggest that antipredator behaviors in turkey vultures, particularly stimulus processing and response, might not be well tuned to vehicles approaching at speeds ≥ 90 kph. The possible inability of turkey vultures to react appropriately to high-speed vehicles could be common among birds, and might represent an important determinant of bird-vehicle collisions.

  18. 75 FR 77524 - Special Conditions: Sikorsky Aircraft Corporation Model S-92A Helicopter; Installation of a...

    Science.gov (United States)

    2010-12-13

    ... it plainly visible to and usable by any pilot at their station. (4) A system providing the aircraft longitudinal and lateral ground speeds and the pilot-selected longitudinal and lateral ground speeds when...

  19. Speeding up biomolecular interactions by molecular sledding

    NARCIS (Netherlands)

    Turkin, Alexander; Zhang, Lei; Marcozzi, Alessio; Mangel, Walter F; Herrmann, Andreas; van Oijen, Antoine M

    2016-01-01

    Numerous biological processes involve association of a protein with its binding partner, an event that is preceded by a diffusion-mediated search bringing the two partners together. Often hindered by crowding in biologically relevant environments, three-dimensional diffusion can be slow and result i

  20. Learning by Investing, Embodiment, and Speed of Convergence

    DEFF Research Database (Denmark)

    Groth, Christian; Wendner, Ronald

    This paper sets up a dynamic general equilibrium model to study how the composition of technical progress affects the asymptotic speed of convergence. The following questions are addressed: Will endogenizing a fraction of the productivity increases as coming from learning by investing help...... to generate a low asymptotic speed of convergence in accordance with the empirical evidence? Does it matter whether learning originates in gross or net investment? The answers to both questions turn out to be: yes, a lot. The third question addressed is: Does the speed of convergence significantly depend...... on the degree to which learning by investing takes the embodied form rather than the disembodied form? The answer turns out to be: no. These results point to a speed of convergence on the small side of 2% per year and possibly tending to a lower level in the future due to the rising importance of investment...

  1. Pneumatic motor speed control by trajectory tracking fuzzy logic controller

    Indian Academy of Sciences (India)

    Cengiz Safak; Vedat Topuz; A Fevzi Baba

    2010-02-01

    In this study, trajectory tracking fuzzy logic controller (TTFLC) is proposed for the speed control of a pneumatic motor (PM). A third order trajectory is defined to determine the trajectory function that has to be tracked by the PM speed. Genetic algorithm (GA) is used to find the TTFLC boundary values of membership functions (MF) and weights of control rules. In addition, artificial neural networks (ANN) modelled dynamic behaviour of PM is given. This ANN model is used to find the optimal TTFLC parameters by offline GA approach. The experimental results show that designed TTFLC successfully enables the PM speed track the given trajectory under various working conditions. The proposed approach is superior to PID controller. It also provides simple and easy design procedure for the PM speed control problem.

  2. Effects of engine emissions from high-speed civil transport aircraft: A two-dimensional modeling study, part 2

    Science.gov (United States)

    Ko, Malcolm K. W.; Weisenstein, Debra K.; Sze, Nein Dak; Shia, Run-Lie; Rodriguez, Jose M.; Heisey, Curtis

    1991-01-01

    The AER two-dimensional chemistry-transport model is used to study the effect of supersonic and subsonic aircraft operation in the 2010 atmosphere on stratospheric ozone (O3). The results show that: (1) the calculated O3 response is smaller in the 2010 atmosphere compared to previous calculations performed in the 1980 atmosphere; (2) with the emissions provided, the calculated decrease in O3 column is less than 1 percent; and (3) the effect of model grid resolution on O3 response is small provided that the physics is not modified.

  3. High-speed quantum networking by ship.

    Science.gov (United States)

    Devitt, Simon J; Greentree, Andrew D; Stephens, Ashley M; Van Meter, Rodney

    2016-11-02

    Networked entanglement is an essential component for a plethora of quantum computation and communication protocols. Direct transmission of quantum signals over long distances is prevented by fibre attenuation and the no-cloning theorem, motivating the development of quantum repeaters, designed to purify entanglement, extending its range. Quantum repeaters have been demonstrated over short distances, but error-corrected, global repeater networks with high bandwidth require new technology. Here we show that error corrected quantum memories installed in cargo containers and carried by ship can provide a exible connection between local networks, enabling low-latency, high-fidelity quantum communication across global distances at higher bandwidths than previously proposed. With demonstrations of technology with sufficient fidelity to enable topological error-correction, implementation of the quantum memories is within reach, and bandwidth increases with improvements in fabrication. Our approach to quantum networking avoids technological restrictions of repeater deployment, providing an alternate path to a worldwide Quantum Internet.

  4. High-speed quantum networking by ship

    Science.gov (United States)

    Devitt, Simon J.; Greentree, Andrew D.; Stephens, Ashley M.; van Meter, Rodney

    2016-11-01

    Networked entanglement is an essential component for a plethora of quantum computation and communication protocols. Direct transmission of quantum signals over long distances is prevented by fibre attenuation and the no-cloning theorem, motivating the development of quantum repeaters, designed to purify entanglement, extending its range. Quantum repeaters have been demonstrated over short distances, but error-corrected, global repeater networks with high bandwidth require new technology. Here we show that error corrected quantum memories installed in cargo containers and carried by ship can provide a exible connection between local networks, enabling low-latency, high-fidelity quantum communication across global distances at higher bandwidths than previously proposed. With demonstrations of technology with sufficient fidelity to enable topological error-correction, implementation of the quantum memories is within reach, and bandwidth increases with improvements in fabrication. Our approach to quantum networking avoids technological restrictions of repeater deployment, providing an alternate path to a worldwide Quantum Internet.

  5. Focusing of Rayleigh waves generated by high-speed trains under the condition of ground vibration boom

    CERN Document Server

    Krylov, Victor V

    2015-01-01

    In the present paper, the effects of focusing of Rayleigh waves generated by high speed trains in the supporting ground under the condition of ground vibration boom are considered theoretically. These effects are similar to the effects of focusing of sound waves radiated by aircraft under the condition of sonic boom. In particular, if a railway track has a bend to provide the possibility of changing direction of train movement, the Rayleigh surface waves generated by high-speed trains under the condition of ground vibration boom may become focused. This results in concentration of their energy along a simple caustic line at one side of the track and in the corresponding increase in ground vibration amplitudes. The effect of focusing of Rayleigh waves may occur also if a train moves along a straight line with acceleration and its current speed is higher than Rayleigh wave velocity in the ground. The obtained results are illustrated by numerical calculations.

  6. Low-Speed Yawed-Rolling Characteristics of a Pair of 56-Inch-Diameter, 32-Ply-Rating, Type 7 Aircraft Tires

    Science.gov (United States)

    Thompson, Wilbur E.; Horne, Walter B.

    1959-01-01

    The low-speed (up to 4 miles per hour) yawed-rolling characteristics of two 56 x 16 32-ply-rating, type 7 aircraft tires under straight-yawed rolling were determined over a range of inflation pressures and yaw angles for a vertical load approximately equal to 75 percent of the rated vertical load. The quantities measured or determined included cornering force, drag force self-alining torque, pneumatic caster vertical tire deflection, yaw angle, and relaxation length. During straight-yawed rolling the normal force generally increased with increasing yaw angle within the test range. The self-alining torque increased to a maximum value and then decreased with increasing angle of yaw. The pneumatic caster tended to decrease with increasing yaw angle.

  7. MIPAS Ozone Validation by Stratospheric Balloon and Aircraft Measurements

    Science.gov (United States)

    Cortesi, U.; Blom, C. E.; Camy-Peyret, C.; Chance, K.; Davies, J.; Goutail, F.; Kuttippurath, J.; McElroy, C. T.; Mencaraglia, F.; Oelhaf, H.; Petritoli, A.; Pirre, M.; Pommereau, J. P.; Ravegnani, F.; Renard, J. B.; Strong, K.

    2004-08-01

    A number of in situ and remote sensing techniques for the measurement of upper tropospheric and stratospheric O3 content was employed during dedicated experiments of the ESABC programme, aiming at the validation of the ENVISAT chemistry payload. In this paper, we will be focusing on the validation of MIPAS off-line products, by presenting the results of the intercomparison between MIPAS O3 vertical profiles and aircraft and balloon correlative measurements. First priority is given to the validation of processor v4.61 data, but individual results of 2002 and 2003 balloon observations are also compared with MIPAS O3 non operational data. Some general remarks are finally expressed, along with specific recommendation to fully exploit the available ESABC validation dataset

  8. 26 CFR 48.4041-14 - Exemption for sale to or use by certain aircraft museums.

    Science.gov (United States)

    2010-04-01

    ... museums. 48.4041-14 Section 48.4041-14 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE....4041-14 Exemption for sale to or use by certain aircraft museums. (a) In general. (1) The tax imposed by section 4041 does not apply to liquids which are sold for use or used by an aircraft museum in...

  9. Tropospheric ozone variability during the East Asian summer monsoon as observed by satellite (IASI), aircraft (MOZAIC) and ground stations

    Science.gov (United States)

    Safieddine, Sarah; Boynard, Anne; Hao, Nan; Huang, Fuxiang; Wang, Lili; Ji, Dongsheng; Barret, Brice; Ghude, Sachin D.; Coheur, Pierre-François; Hurtmans, Daniel; Clerbaux, Cathy

    2016-08-01

    Satellite measurements from the thermal Infrared Atmospheric Sounding Interferometer (IASI), aircraft data from the MOZAIC/IAGOS project, as well as observations from ground-based stations, are used to assess the tropospheric ozone (O3) variability during the East Asian Summer Monsoon (EASM). Six years 2008-2013 of IASI data analysis reveals the ability of the instrument to detect the onset and the progression of the monsoon seen by a decrease in the tropospheric 0-6 km O3 column due to the EASM, and to reproduce this decrease from one year to the other. The year-to-year variability is found to be mainly dependent on meteorology. Focusing on the period of May-August 2011, taken as an example year, IASI data show clear inverse relationship between tropospheric 0-6 km O3 on one hand and meteorological parameters such as cloud cover, relative humidity and wind speed, on the other hand. Aircraft data from the MOZAIC/IAGOS project for the EASM of 2008-2013 are used to validate the IASI data and to assess the effect of the monsoon on the vertical distribution of the tropospheric O3 at different locations. Results show good agreement with a correlation coefficient of 0.73 (12 %) between the 0-6 km O3 column derived from IASI and aircraft data. IASI captures very well the inter-annual variation of tropospheric O3 observed by the aircraft data over the studied domain. Analysis of vertical profiles of the aircraft data shows a decrease in the tropospheric O3 that is more important in the free troposphere than in the boundary layer and at 10-20° N than elsewhere. Ground station data at different locations in India and China show a spatiotemporal dependence on meteorology during the monsoon, with a decrease up to 22 ppbv in Hyderabad, and up to 5 ppbv in the North China Plain.

  10. Study for Air Vehicles at High Speeds, Identifying the Potential Benefits to Transport Aircraft of a Continuously Variable Geometry Trailing-Edge Structure that can be Utilized for Aircraft Control, Trim, Load-Alleviation, and High Lift

    Science.gov (United States)

    2011-08-01

    Fig. 1.1.29 NOTIONAL NEXT GENERATION MOBILTY & TRANSPORTS & CIVIL AIRCRAFT ESTOL CONCEPTS NASA ...This subject is in revival currently. Early proving work has been conducted by NASA on FA- 18 formations. In the time-scale to 2012, Ref.15 mentions...flight research ( NASA & AFRL) into Adaptive Compliant Trailing Edge (ACTE) on a Gulfstream-III, Fig.1.1.23. The conventional TE flaps (19 ft span x

  11. Design the High Speed Kogge-Stone Adder by Using

    Directory of Open Access Journals (Sweden)

    MUX

    2015-08-01

    Full Text Available In this Technical era the high speed and low area of VLSI chip are very- very essential factors. Day by day number of transistors and other active and passive elements are growing on VLSI chip. In Integral part of the processor adders play an important role. In this paper we are using proposed kogge-stone adders for binary addition to reduce the size and increase the efficiency or processors speed. Proposing kogge stone adder provides less components, less path delay and better speed compare to other existing kogge stone adder and other adders. Here we are comparing the kogge stone adders of different-different word size from other adders. The design and experiment can be done by the aid of Xilinx 14.1i Spartan 3 device family.

  12. 19 CFR 122.28 - Private aircraft taken abroad by U.S. residents.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Private aircraft taken abroad by U.S. residents. 122.28 Section 122.28 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY AIR COMMERCE REGULATIONS Private Aircraft § 122.28 Private...

  13. 76 FR 18033 - Airworthiness Directives; Piper Aircraft, Inc. (Type Certificate Previously Held by The New Piper...

    Science.gov (United States)

    2011-04-01

    ...-060-AD; Amendment 39-16635; AD 2011-06-10] RIN 2120-AA64 Airworthiness Directives; Piper Aircraft, Inc. (Type Certificate Previously Held by The New Piper Aircraft, Inc.) Models PA-46-310P, PA- 46-350P, and...: We are superseding an existing airworthiness directive (AD) that applies to certain Piper...

  14. Modelling Of Residual Stresses Induced By High Speed Milling Process

    Science.gov (United States)

    Desmaison, Olivier; Mocellin, Katia; Jardin, Nicolas

    2011-05-01

    Maintenance processes used in heavy industries often include high speed milling operations. The reliability of the post-process material state has to be studied. Numerical simulation appears to be a very interesting way to supply an efficient residual stresses (RS) distribution prediction. Because the adiabatic shear band and the serrated chip shaping are features of the austenitic stainless steel high speed machining, a 2D high speed orthogonal cutting model is briefly presented. This finite element model, developed on Forge® software, is based on data taken from Outeiro & al.'s paper [1]. A new behaviour law fully coupling Johnson-Cook's constitutive law and Latham and Cockcroft's damage model is detailed in this paper. It ensures results that fit those found in literature. Then, the numerical tools used on the 2D model are integrated to a 3D high speed milling model. Residual stresses distribution is analysed, on the surface and into the depth of the material. Various revolutions and passes of the two teeth hemispheric mill on the workpiece are simulated. Thus the sensitivity of the residual stresses generation to the cutting conditions can be discussed. In order to validate the 3D model, a comparison of the cutting forces measured by EDF R&D to those given by numerical simulations is achieved.

  15. Evaluating Speed Enforcement Field Set-Ups Used by Regional Police in Belgium: An Analysis of Speed Outcome Indicators

    Directory of Open Access Journals (Sweden)

    Brenda Wilmots

    2016-12-01

    Full Text Available In this paper the results from a field experiment (conducted in 2012 are presented, in which 3 regional police units in the Flemish region of Belgium each tested a particular combination of a speed control (with mobile radar in an anonymous car with communicative signage. The goal of this paper was to scientifically evaluate frequently used field set-ups. The following set-ups were tested in one week: (1 police unit 1: speed control with and without a static feedback sign placed after the control; (2 police unit 2: speed control with and without a digital feedback sign placed after the control; (3 police unit 3: speed display followed by a second speed display further along the road section. During certain time frames, speed control took place in between both signs. All tested field set-ups generated significant reductions in the speed level. Studying the effect of the different variations for each set-up reveals that the effect of the speed control is generally larger in combination with the signage alongside the road. After the period during which the police activities took place, speed levels again reached their initial level. Based on the before–after analysis, only in police area 2 was a small ‘time halo-effect’ found. To generalize results from this pilot study, repetition of tested set-ups in the field is recommended as well as testing on a larger scale.

  16. Speeding Up Simulations By Slowing Down Particles: Speed-Limited Particle-In-Cell Simulation

    CERN Document Server

    Werner, Gregory R

    2015-01-01

    Particle-in-cell (PIC) simulation is often impractical for the same reason that it is powerful: it includes too much physics. Sometimes the mere ability to simulate physics on small length or time scales requires those scales to be resolved (by the cell size and timestep) to avoid instability, even when the effects at those scales contribute negligibly to the phenomenon motivating the simulation. For example, a timestep larger than the inverse plasma frequency will often result in unphysical growth of plasma oscillations, even in simulations where plasma oscillations should not arise at all. Larger timesteps are possible in simulations based on reduced physics models, such as MHD or gyrokinetics, or in simulations with implicit time-advances. A new method, speed-limited PIC (SLPIC) simulation, allows larger timesteps without reduced physics and with an explicit time-advance. The SLPIC method slows down fast particles while still accurately representing the particle distribution. SLPIC is valid when fields and...

  17. Speed Control of Induction Motor by Using Variable Frequency

    OpenAIRE

    Drive Pooja Shinde; Rupali Burungale

    2014-01-01

    The variable speed drive is focused on voltage amplitude control. However, its only control speed in constraint limits. The load on Induction Motor is not constant & vary as per load requirement. so speed must be change as per load. If the supply voltage decreased motor torque also decreases, for maintaining same torque, slip decreases hence speed falls and motor speed is directly proportional to supply frequency, hence to maintain a speed, the supply V/F ratio must be vary ac...

  18. Determination of aminocresol isomers by high-speed liquid chromatography.

    Science.gov (United States)

    Sakurai, H; Kito, M

    Aminocresol isomers (4-hydroxy-m-toluidine [II], 3-hydroxy-p-toluidine [II], 2-hydroxy-p-toluidine [III]) and p-aminophenol have been separated and determined by a high-speed liquid Chromatographie method. Since this method is applicable in aqueous media, it was used to investigate the suitability of a haemin-cysteine system as a model for the cytochrome P-450 mono-oxygenase system, by determination of the [I], [II], [III] and p-aminophenol formed.

  19. Sex speeds adaptation by altering the dynamics of molecular evolution.

    Science.gov (United States)

    McDonald, Michael J; Rice, Daniel P; Desai, Michael M

    2016-03-10

    Sex and recombination are pervasive throughout nature despite their substantial costs. Understanding the evolutionary forces that maintain these phenomena is a central challenge in biology. One longstanding hypothesis argues that sex is beneficial because recombination speeds adaptation. Theory has proposed several distinct population genetic mechanisms that could underlie this advantage. For example, sex can promote the fixation of beneficial mutations either by alleviating interference competition (the Fisher-Muller effect) or by separating them from deleterious load (the ruby in the rubbish effect). Previous experiments confirm that sex can increase the rate of adaptation, but these studies did not observe the evolutionary dynamics that drive this effect at the genomic level. Here we present the first, to our knowledge, comparison between the sequence-level dynamics of adaptation in experimental sexual and asexual Saccharomyces cerevisiae populations, which allows us to identify the specific mechanisms by which sex speeds adaptation. We find that sex alters the molecular signatures of evolution by changing the spectrum of mutations that fix, and confirm theoretical predictions that it does so by alleviating clonal interference. We also show that substantially deleterious mutations hitchhike to fixation in adapting asexual populations. In contrast, recombination prevents such mutations from fixing. Our results demonstrate that sex both speeds adaptation and alters its molecular signature by allowing natural selection to more efficiently sort beneficial from deleterious mutations.

  20. Modulation of Saturn's radio clock by solar wind speed.

    Science.gov (United States)

    Zarka, Philippe; Lamy, Laurent; Cecconi, Baptiste; Prangé, Renée; Rucker, Helmut O

    2007-11-08

    The internal rotation rates of the giant planets can be estimated by cloud motions, but such an approach is not very precise because absolute wind speeds are not known a priori and depend on latitude: periodicities in the radio emissions, thought to be tied to the internal planetary magnetic field, are used instead. Saturn, despite an apparently axisymmetric magnetic field, emits kilometre-wavelength (radio) photons from auroral sources. This emission is modulated at a period initially identified as 10 h 39 min 24 +/- 7 s, and this has been adopted as Saturn's rotation period. Subsequent observations, however, revealed that this period varies by +/-6 min on a timescale of several months to years. Here we report that the kilometric radiation period varies systematically by +/-1% with a characteristic timescale of 20-30 days. Here we show that these fluctuations are correlated with solar wind speed at Saturn, meaning that Saturn's radio clock is controlled, at least in part, by conditions external to the planet's magnetosphere. No correlation is found with the solar wind density, dynamic pressure or magnetic field; the solar wind speed therefore has a special function. We also show that the long-term fluctuations are simply an average of the short-term ones, and therefore the long-term variations are probably also driven by changes in the solar wind.

  1. Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

    Directory of Open Access Journals (Sweden)

    Shih-Chen Shi

    2016-07-01

    Full Text Available The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC, hydroxypropyl methylcellulose phthalate (HPMCP, and hydroxypropyl methylcellulose acetate succinate (HPMCAS film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate promising anti-corrosion performance of HPMC and HPMCP. With increasing film thickness, both materials reveal improvement in corrosion inhibition. Moreover, because of a hydrophobic surface and lower moisture content, HPMCP shows better anti-corrosion performance than HPMCAS. The study is of certain importance for designing green corrosion inhibitors of high speed steel surfaces by the use of biopolymer derivatives.

  2. Flux Sampling Errors for Aircraft and Towers

    Science.gov (United States)

    Mahrt, Larry

    1998-01-01

    Various errors and influences leading to differences between tower- and aircraft-measured fluxes are surveyed. This survey is motivated by reports in the literature that aircraft fluxes are sometimes smaller than tower-measured fluxes. Both tower and aircraft flux errors are larger with surface heterogeneity due to several independent effects. Surface heterogeneity may cause tower flux errors to increase with decreasing wind speed. Techniques to assess flux sampling error are reviewed. Such error estimates suffer various degrees of inapplicability in real geophysical time series due to nonstationarity of tower time series (or inhomogeneity of aircraft data). A new measure for nonstationarity is developed that eliminates assumptions on the form of the nonstationarity inherent in previous methods. When this nonstationarity measure becomes large, the surface energy imbalance increases sharply. Finally, strategies for obtaining adequate flux sampling using repeated aircraft passes and grid patterns are outlined.

  3. 19 CFR 10.183 - Duty-free entry of civil aircraft, aircraft engines, ground flight simulators, parts, components...

    Science.gov (United States)

    2010-04-01

    ... Duty-free entry of civil aircraft, aircraft engines, ground flight simulators, parts, components, and... aircraft, aircraft engines, and ground flight simulators, including their parts, components, and... United States (HTSUS) by meeting the following requirements: (1) The aircraft, aircraft engines,...

  4. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2002-11-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  5. Research related to variable sweep aircraft development

    Science.gov (United States)

    Polhamus, E. C.; Toll, T. A.

    1981-01-01

    Development in high speed, variable sweep aircraft research is reviewed. The 1946 Langley wind tunnel studies related to variable oblique and variable sweep wings and results from the X-5 and the XF1OF variable sweep aircraft are discussed. A joint program with the British, evaluation of the British "Swallow", development of the outboard pivot wing/aft tail configuration concept by Langley, and the applied research program that followed and which provided the technology for the current, variable sweep military aircraft is outlined. The relative state of variable sweep as a design option is also covered.

  6. Flicker Mitigation by Speed Control of Permanent Magnet Synchronous Generator Variable-Speed Wind Turbines

    DEFF Research Database (Denmark)

    Hu, Weihao; Zhang, Yunqian; Chen, Zhe;

    2013-01-01

    Grid-connected wind turbines are fluctuating power sources that may produce flicker during continuous operation. This paper presents a simulation model of a MW-level variable speed wind turbine with a full-scale back-to-back power converter and permanent magnet synchronous generator (PMSG...

  7. Improved road traffic emission inventories by adding mean speed distributions

    NARCIS (Netherlands)

    Smit, R.; Poelman, M.; Schrijver, J.

    2008-01-01

    Does consideration of average speed distributions on roads-as compared to single mean speed-lead to different results in emission modelling of large road networks? To address this question, a post-processing method is developed to predict mean speed distributions using available traffic data from a

  8. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2003-01-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. For the engine considered, the upper limit for the ion emission index EIi is of the order of (2-5 x1016 ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. The results also show that most of the soot particles are either positively or negatively charged, the remaining neutral particles representing approximately 20% of the total particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  9. Experimental investigation of the cornering characteristics of 18 by 5.5, type 7, aircraft tires with different tread patterns

    Science.gov (United States)

    Dreher, R. C.; Tanner, J. A.

    1974-01-01

    The characteristics, which include the cornering-force and drag-force friction coefficients and self-alining torque, were obtained on dry, damp, and flooded runway surfaces over a range of yaw angles from 0 deg to 12 deg and at ground speeds from approximately 5 to 90 knots. The results indicate that a tread pattern with pinholes in the ribs reduces the tire cornering capability at high yaw angles on a damp surface but improves cornering on a dry surface. A tread pattern which has transverse grooves across the entire width of the tread improves the tire cornering performance slightly at high speeds on the flooded runway surface. The cornering capability of all the tires is degraded at high ground speeds by thin film lubrication and/or tire hydroplaning effects. Alterations to the conventional tread pattern provide only marginal improvements in the tire cornering capability which suggests that runway surface treatments may be a more effective way of improving aircraft ground performance during wet operations.

  10. High-speed digital phonoscopy images analyzed by Nyquist plots

    Science.gov (United States)

    Yan, Yuling

    2012-02-01

    Vocal-fold vibration is a key dynamic event in voice production, and the vibratory characteristics of the vocal fold correlate closely with voice quality and health condition. Laryngeal imaging provides direct means to observe the vocal fold vibration; in the past, however, available modalities were either too slow or impractical to resolve the actual vocal fold vibrations. This limitation has now been overcome by high-speed digital imaging (HSDI) (or high-speed digital phonoscopy), which records images of the vibrating vocal folds at a rate of 2000 frames per second or higher- fast enough to resolve a specific, sustained phonatory vocal fold vibration. The subsequent image-based functional analysis of voice is essential to better understanding the mechanism underlying voice production, as well as assisting the clinical diagnosis of voice disorders. Our primary objective is to develop a comprehensive analytical platform for voice analysis using the HSDI recordings. So far, we have developed various analytical approaches for the HSDI-based voice analyses. These include Nyquist plots and associated analysese that are used along with FFT and Spectrogram in the analysis of the HSDI data representing normal voice and specific voice pathologies.

  11. Surface roughness measurement on a wing aircraft by speckle correlation.

    Science.gov (United States)

    Salazar, Félix; Barrientos, Alberto

    2013-09-05

    The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given.

  12. High Speed Crystal Growth by Q-switched Laser Melting

    Science.gov (United States)

    Cullis, A. G.

    1984-01-01

    The modification of the structural and electrical properties of semiconductors short radiation pulses obtained from Q-switched lasers is described. These modifications are accomplished by high heating and cooling rates. This processing revealed novel crystal growth and high speed resolidification phenomena. The behavior of semiconductor Si is analyzed. The annealing process typically employs short pulses of radiation in or near the visible region of the spectrum. The Q-switched ruby and Nd-YAG lasers are commonly used and these are sometimes mode locked to reduce the pulse length still further. Material to be annealed can be processed with a single large area radiation spot. Alternatively, a small radiation spot size can be used and a large sample area is covered by overlapping irradiated regions.

  13. Speed Control of Induction Motor by Using Variable Frequency

    Directory of Open Access Journals (Sweden)

    Drive Pooja Shinde

    2014-04-01

    Full Text Available The variable speed drive is focused on voltage amplitude control. However, its only control speed in constraint limits. The load on Induction Motor is not constant & vary as per load requirement. so speed must be change as per load. If the supply voltage decreased motor torque also decreases, for maintaining same torque, slip decreases hence speed falls and motor speed is directly proportional to supply frequency, hence to maintain a speed, the supply V/F ratio must be vary accordingly. But the speed is not vary proportion to application so it consume the rated power and it becomes economically disadvantages. To overcome above problem a new concept of Variable Frequency Drive (VFD is introduced. Adding a Variable Frequency Drive (VFD to a motor driven system can offer potential energy saving in a system in which the load vary with time. The primary function of VFD in application is to provide energy saving, speed reduction of 20% can save energy upto 50%.

  14. Perception of aircraft Deviation Cues

    Science.gov (United States)

    Martin, Lynne; Azuma, Ronald; Fox, Jason; Verma, Savita; Lozito, Sandra

    2005-01-01

    To begin to address the need for new displays, required by a future airspace concept to support new roles that will be assigned to flight crews, a study of potentially informative display cues was undertaken. Two cues were tested on a simple plan display - aircraft trajectory and flight corridor. Of particular interest was the speed and accuracy with which participants could detect an aircraft deviating outside its flight corridor. Presence of the trajectory cue significantly reduced participant reaction time to a deviation while the flight corridor cue did not. Although non-significant, the flight corridor cue seemed to have a relationship with the accuracy of participants judgments rather than their speed. As this is the second of a series of studies, these issues will be addressed further in future studies.

  15. Global contrail coverage simulated by CAM5 with the inventory of 2006 global aircraft emissions

    Directory of Open Access Journals (Sweden)

    Cheryl Craig

    2012-04-01

    Full Text Available This paper documents the incorporation of an inventory of the AEDT (Aviation Environmental Design Tool global commercial aircraft emissions for the year of 2006 into the National Center for Atmospheric Research Community Earth System Model (CESM version 1. The original dataset reports aircraft emission mass of ten specieson an hourly basis which is converted to monthly emission mixing ratio tendencies as the released version of the dataset. We also describe how the released aircraft emission dataset is incorporated into CESM.A contrail parameterization is implemented in the CESM in which it isassumed that persistent contrails initially form when aircraft water vapor emissions experience a favorable atmospheric environment. Both aircraft emissions and ambient humidity are attributed to the formation of contrails. The ice water content of contrails is assumed to follow an empirical function of atmospheric temperature which determines the cloud fraction associated with contrails.Our modeling study indicates that the simulated global contrail coverage is sensitive to the vertical resolution of the GCMsin the upper troposphere and lower stratosphere because of modelassumptions about the vertical overlap structure of clouds.Futhermore, the extent of global contrail coverage simulated by CESM exhibits a seasonal cycle which is in broad agreement with observations.

  16. Qualitative Research of AZ31 Magnesium Alloy Aircraft Brackets Produced by a New Forging Method

    Directory of Open Access Journals (Sweden)

    Dziubińska A.

    2016-06-01

    Full Text Available The paper reports a selection of numerical and experimental results of a new closed-die forging method for producing AZ31 magnesium alloy aircraft brackets with one rib. The numerical modelling of the new forming process was performed by the finite element method.The distributions of stresses, strains, temperature and forces were examined. The numerical results confirmed that the forgings produced by the new forming method are correct. For this reason, the new forming process was verified experimentally. The experimental results showed good agreement with the numerical results. The produced forgings of AZ31 magnesium alloy aircraft brackets with one rib were then subjected to qualitative tests.

  17. Propulsion controlled aircraft computer

    Science.gov (United States)

    Cogan, Bruce R. (Inventor)

    2010-01-01

    A low-cost, easily retrofit Propulsion Controlled Aircraft (PCA) system for use on a wide range of commercial and military aircraft consists of an propulsion controlled aircraft computer that reads in aircraft data including aircraft state, pilot commands and other related data, calculates aircraft throttle position for a given maneuver commanded by the pilot, and then displays both current and calculated throttle position on a cockpit display to show the pilot where to move throttles to achieve the commanded maneuver, or is automatically sent digitally to command the engines directly.

  18. Size speed bias or size arrival effect-How judgments of vehicles' approach speed and time to arrival are influenced by the vehicles' size.

    Science.gov (United States)

    Petzoldt, Tibor

    2016-10-01

    Crashes at railway level crossings are a key problem for railway operations. It has been suggested that a potential explanation for such crashes might lie in a so-called size speed bias, which describes the phenomenon that observers underestimate the speed of larger objects, such as aircraft or trains. While there is some evidence that this size speed bias indeed exists, it is somewhat at odds with another well researched phenomenon, the size arrival effect. When asked to judge the time it takes an approaching object to arrive at a predefined position (time to arrival, TTA), observers tend to provide lower estimates for larger objects. In that case, road users' crossing decisions when confronted with larger vehicles should be rather conservative, which has been confirmed in multiple studies on gap acceptance. The aim of the experiment reported in this paper was to clarify the relationship between size speed bias and size arrival effect. Employing a relative judgment task, both speed and TTA estimates were assessed for virtual depictions of a train and a truck, using a car as a reference to compare against. The results confirmed the size speed bias for the speed judgments, with both train and truck being perceived as travelling slower than the car. A comparable bias was also present in the TTA estimates for the truck. In contrast, no size arrival effect could be found for the train or the truck, neither in the speed nor the TTA judgments. This finding is inconsistent with the fact that crossing behaviour when confronted with larger vehicles appears to be consistently more conservative. This discrepancy might be interpreted as an indication that factors other than perceived speed or TTA play an important role for the differences in gap acceptance between different types of vehicles.

  19. Aircraft-on-ground path following control by dynamical adaptive backstepping

    Institute of Scientific and Technical Information of China (English)

    Chen Bihua; Jiao Zongxia; Shuzhi Sam Ge

    2013-01-01

    The necessity of improving the air traffic and reducing the aviation emissions drives to investigate automatic steering for aircraft to effectively roll on the ground.This paper addresses the path following control problem of aircraft-on-ground and focuses on the task that the aircraft is required to follow the desired path on the runway by nose wheel automatic steering.The proposed approach is based on dynamical adaptive backstepping so that the system model does not have to be transformed into a canonical triangular form which is necessary in conventional backstepping design.This adaptive controller performs well despite the lack of information on the aerodynamic load and the tire cornering stiffness parameters.Simulation results clearly demonstrate the advantages and effectiveness of the proposed approach.

  20. Speed Control of Bldc Motor Drive By Using Pid Controllers

    Directory of Open Access Journals (Sweden)

    Y.Narendra Kumar,

    2014-04-01

    Full Text Available This paper mainly deals with the Brushless DC (BLDC motor speed driving systems have sprouted in various small scale and large scale applications like automobile industries, domestic appliances etc. This leads to the development in Brushless DC motor (BLDCM. The usage of BLDC Motor enhances various performance factors ranging from higher efficiency, higher torque in low-speed range, high power density ,low maintenance and less noise than other motors. The BLDC Motor can act as an alternative for traditional motors like induction and switched reluctance motors. In this paper PID controller is implemented with speed feedback loop and it is observe that torque ripples are minimized. Simulation is carried out using MATLAB / SIMULINK. The results show that the performance of BLDC Motor is quite satisfactory for various loading conditions. Brushless DC motor drives are typically employed in speed controlled applications.

  1. Speed of light as measured by two terrestrial stable clocks

    Science.gov (United States)

    Hsu, J. P.; Sherry, T. N.; Chiu, C. B.

    1977-01-01

    Despite the recent criticism within the special theory of relativity, there exists an arrangement of stable clocks rotating with the earth which predicts diurnal variations of the one-way speed of light, as suggested previously.

  2. 31 CFR 515.548 - Services rendered by Cuba to United States aircraft.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Services rendered by Cuba to United... REGULATIONS Licenses, Authorizations, and Statements of Licensing Policy § 515.548 Services rendered by Cuba to United States aircraft. Specific licenses are issued for payment to Cuba of charges for...

  3. Application Research on Reducing Aircraft Cruising Speed in Ground Delay Program%降低飞机巡航速度在地面等待程序中的应用研究

    Institute of Scientific and Technical Information of China (English)

    刘继新; 李开建; 吴懿君

    2015-01-01

    GDP whose cancellation time is generally earlier than its expected end time , is an important method in ATFM.The early cancellation of GDP results not only in unnecessary ground holding ,but also in inadequate utilization of airports and airspace .A strategy of reducing aircraft cruising speed is put for-ward in this paper to better allocate the ground holding time and airborne holding time .The strategy aims to fly the aircraft at a low speed with the same fuel consumption as that in the flight plan to enable the air -craft to obtain maximum airborne holding time .Once GDP is canceled ahead of time ,the aircraft is to fly at the planned speed in order to reduce partial delay .The simulation results show that if GDP is cancelled 30 minutes in advance,the application of strategy of reducing aircraft cruising speed could reduce 6.9 percent of GDP overall delay .%地面等待程序( GDP)作为空中交通流量管理的一种重要手段,它取消的时间往往早于其预计结束时间。针对GDP的提前取消不仅会造成不必要的地面等待,也使得机场、空域不能被充分利用的问题,提出了一种降低飞机巡航速度的策略来更好地分配地面等待和空中等待时间比例。这一策略旨在让飞机以一个和飞行计划相同油耗水平的低速飞行,使得飞机获得最大的空中等待时间,一旦GDP提前取消,飞机就以计划飞行速度飞行,从而减少部分延误。仿真结果表明,GDP提前30 min取消,减速策略的应用可使GDP整体延误水平降低6.9%。

  4. PM EMISSIONS PRODUCED BY AIRCRAFT UNDER THE OPERATIONS AT THE AIRPORT

    Directory of Open Access Journals (Sweden)

    Oleksandr Zaporozhets

    2016-12-01

    Full Text Available Purpose: The effects of aircraft engine emissions within the planetary boundary layer under the landing/ take-off operations contribute sufficiently to deterioration of air pollution in the vicinity of the airports and nearby residential areas. Currently the primary object of airport air quality are the nitrogen oxides and particle matter (PM10, PM2.5 and ultrafine PM emissions from aircraft engine exhausts as initiators of photochemical smog and regional haze, which may further impact on human health. Analysis of PM emission inventory results at major European airports highlighted on sufficiently high contribution of aircraft engines and APU. The paper aims to summarize the knowledge on particle size distributions, particle effective density, morphology and internal structure of aircraft PM, these properties are critical for understanding of the fate and potential health impact of PM. It also aims to describe the basic methods for calculation of emission and dispersion of PM, produced by aircrafts under the LTO operations. Methods: analytical solution of the atmospheric diffusion equation is used to calculate the maximum PM concentration from point emission source. The PM concentration varies inversely proportional to the wind velocity u1 and directly proportional to the vertical component of the turbulent exchange coefficient k1/u1. The evaluation of non-volatile PM concentration includes the size and shape of PM. PolEmiCa calculates the distributions of PM fractions for aircraft and APU exhausts (height of installation was given H=4,5m like for Tupolev-154. Results: The maximum concentration of PM in exhaust from APU is higher and appropriate distance is less than in case for gas. PM polydispersity leads to the separation of maximums concentration in space for individual fractions on the wind direction and therefore it contributes to the reduction of maximum total concentration. Discussion:But although the APU has contributed significantly to

  5. Possible Origin Of The Neutrino Speed Anomaly Reported By OPERA

    CERN Document Server

    Dado, Shlomo

    2011-01-01

    Recently the OPERA collaboration reported a measurement of a superluminal speed of muon neutrinos travelling through the Earth's crust between their production site at CERN and their detection site under Gran Sasso, ~730 km away. The measurement was based on the assumption that the pulse shape of the neutrinos from the decay of parent mesons produced in proton-target collisions is the same as that of the incident protons. Here we argue that the effective column density of the target along the beam direction decreases with time during the 10.5 microseconds duration of the proton pulse. This is because of the thermal expansion and expulsion of target material along the beam by the energy-momentum deposition during the 10.5 microseconds pulse. The progresive reduction in the effective column density during the pulse decreases the neutrino production rate per incident proton. It could have advanced the mean production time of the detected neutrinos relative to that calculated from the proton pulse-shape, by an am...

  6. Convective high-speed flow and field-aligned high-speed flows explored by TC-1

    Institute of Scientific and Technical Information of China (English)

    ZHANG LingQian; LIU ZhenXing; MA ZhiWei; W.BAUMJOHANN; M.W.DUNLOP4; WANG GuangJun; WANG Xiao; H.REME; C.CARR

    2008-01-01

    From June 1, 2004 to October 31, 2006, a total 465 high-speed flow events are observed by the TC-1 satellite in the near-Earth region (-13 RE < X < -9 RE, |Y|<10 RE, |2|<5 RE). Based on the angle between the flow and the magnetic field, the high-speed flow events are further divided into two types, that is,field-aligned high-speed flow (FAHF) in the plasma sheet boundary and convective bursty bulk flow (BBF) in the center plasma sheet. Among the total 465 high-speed flow events, there are 371 FAHFs,and 94 BBFs. The CHF are mainly concentrated in the plasma sheet, the intersection angle between the flow and the magnetic field is larger, the magnetic field intensity is relatively weak. The FHF are mainly distributed near the boundary layer of the plasma sheet, the intersection angle between the flow and magnetic field is smaller, and the magnetic field intensity is relatively strong. The convective BBFs have an important effect on the substorm.

  7. Active aeroelastic control aspects of an aircraft wing by using synthetic jet actuators: modeling, simulations, experiments

    NARCIS (Netherlands)

    Donnell, K.O.; Schober, S.; Stolk, M.; Marzocca, P.; De Breuker, R.; Abdalla M.; Nicolini, E.; Gürdal, Z.

    2007-01-01

    This paper discusses modeling, simulations and experimental aspects of active aeroelastic control on aircraft wings by using Synthetic Jet Actuators (SJAs). SJAs, a particular class of zero-net mass-flux actuators, have shown very promising results in numerous aeronautical applications, such as boun

  8. Improving Road Safety of Tank Truck in Indonesia by Speed Limiter Installation

    Directory of Open Access Journals (Sweden)

    Pranoto Hadi

    2017-01-01

    Full Text Available Indonesia has one of the highest number of fatalities caused by traffic accident. It is become main concern since last decades. Approximately of 10% fatalities is caused by tank truck accident, it recorded by PT. Pertamina Persero, Indonesia in 2015 that 17% and 20% tank truck accident is caused by over speed and fatigue, respectively. Therefore, over speed has become main factor the occurrence of tank truck accident. Main objective of this research is to install speed limiter on the tank truck in order to improve safety engineering system, decrease accident and to maintain engine performance. This research is conducted in Indonesia especially in Java-Bali route travel. Speed limiter is installed to the tank truck engine which completed by fuel cut-off solenoid to reduce the speed automatically when it exceeding the maximum speed that has been determined. From the result shows that top speed which performed by driver up to 133 km/h when tank truck uninstalled by speed limiter. Meanwhile, when speed limiter is installed to the tank truck, top speed locked at 70 km/h even though the driver want to speed up. It means that fuel cut-off system is very effective to lock the speed at 70 km/h and it shown the improvement up to 65%. The monitoring activities observed that the decreasing number of fatalities caused by tank truck accident become 7% as compared to last year of 17%. It can be found that the speed limiter coupled by speed recorder was very efficient to improve safety engineering system of the tank truck.

  9. Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

    OpenAIRE

    Shih-Chen Shi; Chieh-Chang Su

    2016-01-01

    The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS) film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate prom...

  10. The computational and experimental investigation on winglets of a low speed aircraft%低速飞机加装翼梢小翼的CFD数值计算及风洞试验研究

    Institute of Scientific and Technical Information of China (English)

    刘毅; 赵晓霞; 江宗辉; 任庆祝

    2015-01-01

    An aircraft with four turbo-propeller engines is characterized by low speed and relative high cruise lift coefficient.Winglets are utilized to improve the flow condition around the wing tips and increase the lift-to-drag ratio.CFD calculation and wind tunnel tests show that the lift-to-drag ratio at endurance cruise can be increased by 8%,while the lift-to-drag ratio at range cruise can be increased by 4.8% after the optimization of geometric parameters.The results of CFD simulation about the aerodynamic characteristics of the winglet agree well with wind tunnel test results, which could be a convenient and economic method for further optimization of winglet geometry.%针对某四发涡桨飞机飞行速度较低,巡航升力系数较大的特点,通过加装翼梢小翼改善翼尖流场特性而提高巡航升阻比。经数值计算和风洞试验验证表明,几何参数优化后的小翼,可以使飞机久航点升阻比提高8%,远航点升阻比提高4.8%。加装翼梢小翼气动特性的CFD数值计算和风洞试验结果吻合良好,可作为小翼外形进一步优化后快捷、经济的验证手段。

  11. Modulation of walking speed by changing optic flow in persons with stroke

    Directory of Open Access Journals (Sweden)

    Lamontagne Anouk

    2007-06-01

    Full Text Available Abstract Background Walking speed, which is often reduced after stroke, can be influenced by the perception of optic flow (OF speed. The present study aims to: 1 compare the modulation of walking speed in response to OF speed changes between persons with stroke and healthy controls and 2 investigate whether virtual environments (VE manipulating OF speed can be used to promote volitional changes in walking speed post stroke. Methods Twelve persons with stroke and 12 healthy individuals walked on a self-paced treadmill while viewing a virtual corridor in a helmet-mounted display. Two experiments were carried out on the same day. In experiment 1, the speed of an expanding OF was varied sinusoidally at 0.017 Hz (sine duration = 60 s, from 0 to 2 times the subject's comfortable walking speed, for a total duration of 5 minutes. In experiment 2, subjects were exposed to expanding OFs at discrete speeds that ranged from 0.25 to 2 times their comfortable speed. Each test trial was paired with a control trial performed at comfortable speed with matching OF. For each of the test trials, subjects were instructed to walk the distance within the same time as during the immediately preceding control trial. VEs were controlled by the CAREN-2 system (Motek. Instantaneous changes in gait speed (experiment 1 and the ratio of speed changes in the test trial over the control trial (experiment 2 were contrasted between the two groups of subjects. Results When OF speed was changing continuously (experiment 1, an out-of-phase modulation was observed in the gait speed of healthy subjects, such that slower OFs induced faster walking speeds, and vice versa. Persons with stroke displayed weaker (p 0.05, T-test. Conclusion Stroke affects the modulation of gait speed in response to changes in the perception of movement through different OF speeds. Nevertheless, the preservation of even a modest modulation enabled the persons with stroke to increase walking speed when

  12. Friction Wear Property of Brake Materials by Copper-based Powder Metallurgy With Various Brake Speeds

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-xiu; GAO Hong-xia; WEI Xiu-lan

    2004-01-01

    The experiment is conducted on MM-1000 friction test machine, which tests friction wear property of copper-based brake materials by powder metallurgy at different brake speeds. It shows that the coefficient of friction and wear volume are greatly influenced by brake speed. When the brake speed is 4000 r/min, which is a bit higher, the material still has a higher coefficient of friction with 0.47. When the brake speed is over 4000r/min, the coefficient of friction decreased rapidly. When the brake speed is 3000r/min, the material's wear is in its minimum. That is to say no matter how higher or lower the brake speed is the wear volume is bigger relatively. With the brake speed of the lower one it mainly refers to fatigue wear; while of higher one it mainly refers to abradant and oxidation wear.

  13. Dynamic High-speed Knotting of a Rope by a Manipulator

    Directory of Open Access Journals (Sweden)

    Yuji Yamakawa

    2013-10-01

    Full Text Available In this paper we suggest an entirely new strategy for the dexterous manipulation of a linear flexible object, such as rope or a cable, with a high-speed manipulator. We deal with a flexible rope as one example of the linear flexible object. The strategy involves manipulating the object at high-speed. By moving the robot at high-speed, we can assume that the dynamic behaviour of the flexible rope can be obtained by performing algebraic calculations of the high- speed robot motion. Based on this assumption, we derive a dynamic deformation model of the flexible rope and confirm the validity of the proposed model. Then we perform a simulation of dynamic, high-speed knotting based on the proposed model. We also discuss the possibility of forming the knot based on a simple analysis model. Finally, we show experimental results demonstrating dynamic, high-speed knotting with a high-speed manipulator.

  14. Standard Test Method to Determine Color Change and Staining Caused by Aircraft Maintenance Chemicals upon Aircraft Cabin Interior Hard Surfaces

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2001-01-01

    1.1 This test method covers the determination of color change and staining from liquid solutions, such as cleaning or disinfecting chemicals or both, on painted metallic surfaces and nonmetallic surfaces of materials being used inside the aircraft cabin. The effects upon the exposed specimens are measured with the AATCC Gray Scale for Color Change and AATCC Gray Color Scale for Staining. Note 1—This test method is applicable to any colored nonmetallic hard surface in contact with liquids. The selected test specimens are chosen because these materials are present in the majority of aircraft cabin interiors. 1.2This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  15. Modeling Programs Increase Aircraft Design Safety

    Science.gov (United States)

    2012-01-01

    Flutter may sound like a benign word when associated with a flag in a breeze, a butterfly, or seaweed in an ocean current. When used in the context of aerodynamics, however, it describes a highly dangerous, potentially deadly condition. Consider the case of the Lockheed L-188 Electra Turboprop, an airliner that first took to the skies in 1957. Two years later, an Electra plummeted to the ground en route from Houston to Dallas. Within another year, a second Electra crashed. In both cases, all crew and passengers died. Lockheed engineers were at a loss as to why the planes wings were tearing off in midair. For an answer, the company turned to NASA s Transonic Dynamics Tunnel (TDT) at Langley Research Center. At the time, the newly renovated wind tunnel offered engineers the capability of testing aeroelastic qualities in aircraft flying at transonic speeds near or just below the speed of sound. (Aeroelasticity is the interaction between aerodynamic forces and the structural dynamics of an aircraft or other structure.) Through round-the-clock testing in the TDT, NASA and industry researchers discovered the cause: flutter. Flutter occurs when aerodynamic forces acting on a wing cause it to vibrate. As the aircraft moves faster, certain conditions can cause that vibration to multiply and feed off itself, building to greater amplitudes until the flutter causes severe damage or even the destruction of the aircraft. Flutter can impact other structures as well. Famous film footage of the Tacoma Narrows Bridge in Washington in 1940 shows the main span of the bridge collapsing after strong winds generated powerful flutter forces. In the Electra s case, faulty engine mounts allowed a type of flutter known as whirl flutter, generated by the spinning propellers, to transfer to the wings, causing them to vibrate violently enough to tear off. Thanks to the NASA testing, Lockheed was able to correct the Electra s design flaws that led to the flutter conditions and return the

  16. Aerodynamic derivatives for an oblique wing aircraft estimated from flight data by using a maximum likelihood technique

    Science.gov (United States)

    Maine, R. E.

    1978-01-01

    There are several practical problems in using current techniques with five degree of freedom equations to estimate the stability and control derivatives of oblique wing aircraft from flight data. A technique was developed to estimate these derivatives by separating the analysis of the longitudinal and lateral directional motion without neglecting cross coupling effects. Although previously applied to symmetrical aircraft, the technique was not expected to be adequate for oblique wing vehicles. The application of the technique to flight data from a remotely piloted oblique wing aircraft is described. The aircraft instrumentation and data processing were reviewed, with particular emphasis on the digital filtering of the data. A complete set of flight determined stability and control derivative estimates is presented and compared with predictions. The results demonstrated that the relatively simple approach developed was adequate to obtain high quality estimates of the aerodynamic derivatives of such aircraft.

  17. High speed coding for velocity by archerfish retinal ganglion cells

    Directory of Open Access Journals (Sweden)

    Kretschmer Viola

    2012-06-01

    Full Text Available Abstract Background Archerfish show very short behavioural latencies in response to falling prey. This raises the question, which response parameters of retinal ganglion cells to moving stimuli are best suited for fast coding of stimulus speed and direction. Results We compared stimulus reconstruction quality based on the ganglion cell response parameters latency, first interspike interval, and rate. For stimulus reconstruction of moving stimuli using latency was superior to using the other stimulus parameters. This was true for absolute latency, with respect to stimulus onset, as well as for relative latency, with respect to population response onset. Iteratively increasing the number of cells used for reconstruction decreased the calculated error close to zero. Conclusions Latency is the fastest response parameter available to the brain. Therefore, latency coding is best suited for high speed coding of moving objects. The quantitative data of this study are in good accordance with previously published behavioural response latencies.

  18. High Speed Reconfigurable FFT Design by Vedic Mathematics

    CERN Document Server

    Raman, Ashish; Sarin, R K

    2010-01-01

    The Fast Fourier Transform (FFT) is a computationally intensive digital signal processing (DSP) function widely used in applications such as imaging, software-defined radio, wireless communication, instrumentation. In this paper, a reconfigurable FFT design using Vedic multiplier with high speed and small area is presented. Urdhava Triyakbhyam algorithm of ancient Indian Vedic Mathematics is utilized to improve its efficiency. In the proposed architecture, the 4x4 bit multiplication operation is fragmented reconfigurable FFT modules. The 4x4 multiplication modules are implemented using small 2x2bit multipliers. Reconfigurability at run time is provided for attaining power saving. The reconfigurable FFT has been designed, optimized and implemented on an FPGA based system. This reconfigurable FFT is having the high speed and small area as compared to the conventional FFT.

  19. Improving Road Safety of Tank Truck in Indonesia by Speed Limiter Installation

    OpenAIRE

    Pranoto Hadi; Leman A.M; Baba Ishak; Feriyanto Dafit; Putra Gama Widya

    2017-01-01

    Indonesia has one of the highest number of fatalities caused by traffic accident. It is become main concern since last decades. Approximately of 10% fatalities is caused by tank truck accident, it recorded by PT. Pertamina Persero, Indonesia in 2015 that 17% and 20% tank truck accident is caused by over speed and fatigue, respectively. Therefore, over speed has become main factor the occurrence of tank truck accident. Main objective of this research is to install speed limiter on the tank tru...

  20. Design of Through-flow Nacelle for Low-speed Wind Tunnel Testing of Civil Aircraft%民机低速风洞试验通气发房设计

    Institute of Scientific and Technical Information of China (English)

    胡仞与; 张东云; 施永毅

    2014-01-01

    通气发房是民机风洞试验中模拟发动机效应的一种有效手段。通过调整通气发房出口面积,可以对通过发房的流量进行控制,实现所需模拟的流量系数,保证进气流场的几何相似性。失速特性是民机的一个重要的性能指标,大量的低速风洞试验工作都着眼于着落构型下失速特性的研究;而在失速特性的适航审定试飞时的发动机将处于慢车功率状态,因此以模拟慢车流量系数作为低速风洞试验通气发房的设计目标,有助于在风洞试验中对失速特性进行预测。慢车功率时,由于发动机风扇压比很小,如保留外涵喷口形状,通气发房还能近似模拟风扇的喷流效应。发动机在慢车功率下的流量系数在0.5附近,为实现这一流量系数,在设计通气发房时,需调整内涵出口面积,使发房的总出口面积接近唇口面积的一半。 CFD计算证明这种设计方法得到的通气发房基本能够实现预期的流量系数。%Through-flow nacelle ( TFN) is an effective method of simulating engine effect in wind tunnel Testing. By adjusting the nozzle exit areas of a TFN, the flow passing the TFN could be controlled and the flow ratio ( MFR) could be achieved to make sure the similarity around the inlet flow field. As stall characteristics is one of the impor-tant factor in defining civil aircraft performance, a great portion of the low speed wind tunnel tests is devoted to the study of the stall characteristics of aircraft in landing configuration;and due to the fact that engines tend to be set at an idle condition during airworthy flight tests for stall speed determination, designing a TFN with a MFR corre-sponding to an idle power setting is desirable for the prediction of stall characteristics in wind tunnel testing. When running at idle conditions, an engine will have a very low fan pressure ratio, which means if the fan nozzle geometry is maintained, TFN can

  1. Building vibrations induced by noise from rotorcraft and propeller aircraft flyovers

    Science.gov (United States)

    Shepherd, Kevin P.; Hubbard, Harvey H.

    1992-01-01

    Noise and building vibrations were measured for a series of helicopter and propeller-driven aircraft flyovers at WFF during May 1978. The building response data are compared with similar data acquired earlier at sites near Dulles and Kennedy Airports for operation of commercial jet transports, including the Concorde supersonic transport. Results show that noise-induced vibration levels in windows and walls are directly proportional to sound pressure level and that for a given noise level, the acceleration levels induced by a helicopter or a propeller-driven aircraft flyover cannot be distinguished from the acceleration levels induced by a commercial jet transport flyover. Noise-induced building acceleration levels were found to be lower than those levels which might be expected to cause structural damage and were also lower than some acceleration levels induced by such common domestic events as closing windows and doors.

  2. Aircraft Engine Noise Scattering by Fuselage and Wings: A Computational Approach

    Science.gov (United States)

    Stanescu, D.; Hussaini, M. Y.; Farassat, F.

    2003-01-01

    The paper presents a time-domain method for computation of sound radiation from aircraft engine sources to the far-field. The effects of nonuniform flow around the aircraft and scattering of sound by fuselage and wings are accounted for in the formulation. The approach is based on the discretization of the inviscid flow equations through a collocation form of the Discontinuous Galerkin spectral element method. An isoparametric representation of the underlying geometry is used in order to take full advantage of the spectral accuracy of the method. Large-scale computations are made possible by a parallel implementation based on message passing. Results obtained for radiation from an axisymmetric nacelle alone are compared with those obtained when the same nacelle is installed in a generic configuration, with and without a wing.

  3. Numerical modelling of the internal mixing by coagulation of black carbon particles in aircraft exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Ohlsson, S.; Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

    1997-12-31

    When exhaust gases from an aircraft engine mix with ambient air the humidity may reach water saturation and water droplets will form on the available cloud condensation nuclei (CCN). It is still not resolved if the CCN, on which the cloud droplets form, are mainly particles present in the ambient air or particles emitted by the aircraft. It the exhaust from a jet engine the particles are believed to consist mainly of black carbon (BC) and sulfate. The aim is to study, with the help of a numerical model, how a two-component aerosol (i.e. BC and sulfate) in an exhaust trail may be transformed in terms of hygroscopicity by coagulation mixing and how this may depend on the sulfur content in the fuel. (R.P.) 15 refs.

  4. Validation of Aura OMI by Aircraft and Ground-Based Measurements

    Science.gov (United States)

    McPeters, R. D.; Petropavlovskikh, I.; Kroon, M.

    2006-12-01

    Both aircraft-based and ground-based measurements have been used to validate ozone measurements by the OMI instrument on Aura. Three Aura Validation Experiment (AVE) flights have been conducted, in November 2004 and June 2005 with the NASA WB57, and in January/February 2005 with the NASA DC-8. On these flights, validation of OMI was primarily done using data from the CAFS (CCD Actinic Flux Spectroradiometer) instrument, which is used to measure total column ozone above the aircraft. These measurements are used to differentiate changes in stratospheric ozone from changes in total column ozone. Also, changes in ozone over high clouds measured by OMI were checked in a flight over tropical storm Arlene on a flight on June 11th. Ground-based measurements were made during the SAUNA campaign in Sodankyla, Finland, in March and April 2006. Both total column ozone and the ozone vertical distribution were validated.

  5. A new principle and device for large aircraft components gaining accurate support by ball joint

    Institute of Scientific and Technical Information of China (English)

    Bao-gui QIU; Jun-xia JIANG; Ying-lin KE

    2011-01-01

    How to obtain an accurate support for large components by ball joint is a key process in aircraft digital assembly. A novel principle and device is developed to solve the problem. Firstly, the working principle of the device is introduced. When three or four displacement sensors installed in the localizer are touched by the ball-head, the spatial relation is calculated between the large aircraft component's ball-head and the localizer's ball-socket. The localizer is driven to achieve a new position by compensation. Relatively, a support revising algorithm is proposed. The localizer's ball-socket approaches the ball-head based on the displacement sensors. According to the points selected from its spherical surface, the coordinates of ball-head spherical center are computed by geometry. Finally, as a typical application, the device is used to conduct a test-fuselage's ball-head into a localizer's ball-socket. Positional deviations of the spherical centers between the ball-head and the ball-socket in the x, y, and z directions are all controlled within ±0.05 mm under various working conditions. The results of the experiments show that the device has the characteristics of high precision, excellent stability, strong operability, and great potential to be applied widely in the modern aircraft industry.

  6. NASA's advanced control law program for the F-8 digital fly-by-wire aircraft

    Science.gov (United States)

    Elliott, J. R.

    1977-01-01

    This paper briefly describes the NASA F-8 Digital Fly-By-Wire (DFBW) and Langley Research Center's role in investigating and promoting advanced control laws for possible flight experimentation and also provides a brief description of the Phase II DFBW F-8 aircraft and its control system. Some of the advanced control law study objectives and guidelines are discussed, and some mathematical models which are useful in the control analysis problem are provided.

  7. The Juridical Management of the Noise Produced by Aircrafts

    Directory of Open Access Journals (Sweden)

    Florin FAINISI

    2012-06-01

    Full Text Available Noise is a public health problem and, more than that, a source of discomfort perceived strongly by population. World Health Organization (WHO has undertaken studies that have underlined the harmful aspects of noise on the human body, and EU regulations have aligned their requirements to both WHO standards and the standards set by International Civil Aviation Organization (ICAO. At national level, Romania has adopted rules on controlling noise, which transposed the European directives in the field. This study presents the legal measures taken by France to mitigate noise pollution around airports, of which the act establishing compensations for residents for soundproofing homes would be a good example for Romania.

  8. Improving the Response of a Wheel Speed Sensor by Using a RLS Lattice Algorithm

    Science.gov (United States)

    Hernandez, Wilmar

    2006-01-01

    Among the complete family of sensors for automotive safety, consumer and industrial application, speed sensors stand out as one of the most important. Actually, speed sensors have the diversity to be used in a broad range of applications. In today's automotive industry, such sensors are used in the antilock braking system, the traction control system and the electronic stability program. Also, typical applications are cam and crank shaft position/speed and wheel and turbo shaft speed measurement. In addition, they are used to control a variety of functions, including fuel injection, ignition timing in engines, and so on. However, some types of speed sensors cannot respond to very low speeds for different reasons. What is more, the main reason why such sensors are not good at detecting very low speeds is that they are more susceptible to noise when the speed of the target is low. In short, they suffer from noise and generally only work at medium to high speeds. This is one of the drawbacks of the inductive (magnetic reluctance) speed sensors and is the case under study. Furthermore, there are other speed sensors like the differential Hall Effect sensors that are relatively immune to interference and noise, but they cannot detect static fields. This limits their operations to speeds which give a switching frequency greater than a minimum operating frequency. In short, this research is focused on improving the performance of a variable reluctance speed sensor placed in a car under performance tests by using a recursive least-squares (RLS) lattice algorithm. Such an algorithm is situated in an adaptive noise canceller and carries out an optimal estimation of the relevant signal coming from the sensor, which is buried in a broad-band noise background where we have little knowledge of the noise characteristics. The experimental results are satisfactory and show a significant improvement in the signal-to-noise ratio at the system output.

  9. Standard Practice for Corrosion of Aircraft Metals by Total Immersion in Maintenance Chemicals

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This practice covers the determination of the corrosiveness of tank-type aircraft maintenance chemicals on aircraft metals and the corrodibility of metals in these maintenance chemicals with time. The determination is made under conditions of total immersion by a combination of weight change measurements and visual qualitative determinations of change. 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautions, see Section 6.

  10. Estimation Methods for Determination of Drag Characteristics of Fly-by-Wire Aircraft

    Directory of Open Access Journals (Sweden)

    G. Girija

    2001-01-01

    Full Text Available "In this paper, several parameter/state estimation approaches for the determination of drag polars from flight data are described and evaluated for a fly-by-wire (FBW aircraft. Both model-based approaches (MBAs and non-model-based approaches (NMBAs are considered. Dynamic response data from roller coaster and wind- up-turn manoeuvres are generated in a FBW aircraft flight simulator at different flight conditions and the typical performance results are presented. A novel approach to estimate the drag polar has been evaluated. It has been found that the NMBAs perform better than the MBAs. Classically, the MBAs have been used for the determination of drag polars. The merits of an NMBA are that it does not require specification of the detailed model of the aerodynamic coefficients and it can be suitably used for online estimation of drag polars from the flight data of aerospace vehicles

  11. DETECTING DEFECTS IN AIRCRAFT MATERIALS BY NUCLEAR TECHNIQUE (PAS)

    OpenAIRE

    EMAD A. BADAWI

    2005-01-01

    Positron annihilation spectroscopy (PAS) is one of the nuclear techniques used in material science. The present measurements are used to study the behavior of defect concentration in one of the most important materials aluminum alloys which is the 7075 alloy. It has been shown that positrons can become trapped at imperfect locations in solids and their mean lifetime can be influenced by changes in the concentration of such defects. No changes have been observed in the mean lifetime values aft...

  12. Two-dimensional structure of mountain wave observed by aircraft during the PYREX experiment

    Directory of Open Access Journals (Sweden)

    J. L. Attié

    Full Text Available This study presents an experimental analysis from aircraft measurements above the Pyrenees chain during the PYREX experiment. The Pyrenees chain, roughly WE oriented, is a major barrier for northerly and southerly airflows. We present a case of southerly flow (15 October 1990 and three successive cases of northerly flows above the Pyrenees (14, 15 and 16 November 1990 documented by two aircraft. The aircraft have described a vertical cross section perpendicular to the Pyrenean ridge. This area is described via the thermodynamical and dynamical fields which have a horizontal resolution of 10 km. Three methods for computing the vertical velocity of the air are presented. The horizontal advection terms which play a role in the budget equations are also evaluated. The altitude turbulence zone of 15 October are shown via turbulent fluxes, turbulent kinetic energy (TKE, dissipation rate of TKE and inertial length-scale. A comparison of results obtained by eddy-correlation and inertial-dissipation method is presented. The experimental results show a warm and dry downdraft for the southerly flow with large values for advection terms. All the mountain wave cases are also shown to present an important dynamical perturbation just above the Pyrenees at upper altitudes.

  13. Jet Noise Shielding Provided by a Hybrid Wing Body Aircraft

    Science.gov (United States)

    Doty, Michael J.; Brooks, Thomas F.; Burley, Casey L.; Bahr, Christopher J.; Pope, Dennis S.

    2014-01-01

    One approach toward achieving NASA's aggressive N+2 noise goal of 42 EPNdB cumulative margin below Stage 4 is through the use of novel vehicle configurations like the Hybrid Wing Body (HWB). Jet noise measurements from an HWB acoustic test in NASA Langley's 14- by 22-Foot Subsonic Tunnel are described. Two dual-stream, heated Compact Jet Engine Simulator (CJES) units are mounted underneath the inverted HWB model on a traversable support to permit measurement of varying levels of shielding provided by the fuselage. Both an axisymmetric and low noise chevron nozzle set are investigated in the context of shielding. The unshielded chevron nozzle set shows 1 to 2 dB of source noise reduction (relative to the unshielded axisymmetric nozzle set) with some penalties at higher frequencies. Shielding of the axisymmetric nozzles shows up to 6.5 dB of reduction at high frequency. The combination of shielding and low noise chevrons shows benefits beyond the expected additive benefits of the two, up to 10 dB, due to the effective migration of the jet source peak noise location upstream for increased shielding effectiveness. Jet noise source maps from phased array results processed with the Deconvolution Approach for the Mapping of Acoustic Sources (DAMAS) algorithm reinforce these observations.

  14. Static aeroelastic analysis for generic configuration aircraft

    Science.gov (United States)

    Lee, IN; Miura, Hirokazu; Chargin, Mladen K.

    1987-01-01

    A static aeroelastic analysis capability that can calculate flexible air loads for generic configuration aircraft was developed. It was made possible by integrating a finite element structural analysis code (MSC/NASTRAN) and a panel code of aerodynamic analysis based on linear potential flow theory. The framework already built in MSC/NASTRAN was used and the aerodynamic influence coefficient matrix is computed externally and inserted in the NASTRAN by means of a DMAP program. It was shown that deformation and flexible airloads of an oblique wing aircraft can be calculated reliably by this code both in subsonic and supersonic speeds. Preliminary results indicating importance of flexibility in calculating air loads for this type of aircraft are presented.

  15. Characterization of deflagrating munitions by rotating prism high speed photography

    Science.gov (United States)

    Kinsey, Trevor J.; Bussell, Tim J.; Chick, Michael C.

    1992-08-01

    We report on the use of a rotating prism high speed camera for determining the characteristics of a munition undergoing rapid deflagration in field experiments. The technique has been applied to study the controlled deflagration of Composition B filled 105 mm shell and 81 mm mortar bombs as representative thick and thin cased munitions respectively; however the report is mostly illustrated with results from the study on 105 mm shell. The deflagration event has been characterized in terms of case expansion rate, initial fragment velocity, time to case burst, time to reaction from the nose end and the deflagration rate of the filling. Products escaping from the fracturing case eventually obscured the image which limited the extent of the measurement.

  16. Detecting Defects in Aircraft Materials by Nuclear Technique (pas)

    Science.gov (United States)

    Badawi, Emad. A.

    Positron annihilation spectroscopy (PAS) is one of the nuclear techniques used in material science. The present measurements are used to study the behavior of defect concentration in one of the most important materials aluminum alloys which is the 7075 alloy. It has been shown that positrons can become trapped at imperfect locations in solids and their mean lifetime can be influenced by changes in the concentration of such defects. No changes have been observed in the mean lifetime values after the saturation of defect concentration. The mean lifetime and trapping rates are studied for samples deformed up to 58.3%. The concentration of defect range vary from 1015 to 1018cm-3 at the thickness reduction from 2.3 to 58.3%. The dislocation density varies from 108 to 1011cm/cm3.

  17. Annoyance caused by advanced turboprop aircraft flyover noise: Counter-rotating-propeller configuration

    Science.gov (United States)

    Mccurdy, David A.

    1990-01-01

    Two experiments were conducted to quantify the annoyance of people to flyover noise of advanced turboprop aircraft with counter rotating propellers. The first experiment examined configurations having an equal number of blades on each rotor and the second experiment examined configurations having an unequal number of blades on each rotor. The objectives were to determine the effects on annoyance of various tonal characteristics, and to compare annoyance to advanced turboprops with annoyance to conventional turboprops and turbofans. A computer was used to synthesize realistic, time-varying simulations of advanced turboprop aircraft takeoff noise. The simulations represented different combinations fundamental frequency and tone-to-broadband noise ratio. Also included in each experiment were recordings of 10 conventional turboprop and turbofan takeoffs. Each noise was presented at three sound pressure levels in an anechoic chamber. In each experiment, 64 subjects judged the annoyance of each noise stimulus. Analyses indicated that annoyance was significantly affected by the interaction of fundamental frequency with tone-to-broadband noise ratio. No significant differences in annoyance between the advanced turboprop aircraft and the conventional turbofans were found. The use of a duration correction and a modified tone correction improved the annoyance prediction for the stimuli.

  18. 3D pressure imaging of an aircraft propeller blade-tip flow by phase-locked stereoscopic PIV

    Energy Technology Data Exchange (ETDEWEB)

    Ragni, D.; Oudheusden, B.W. van; Scarano, F. [Delft University of Technology, Faculty of Aerospace Engineering, Delft (Netherlands)

    2012-02-15

    The flow field at the tip region of a scaled DHC Beaver aircraft propeller, running at transonic speed, has been investigated by means of a multi-plane stereoscopic particle image velocimetry setup. Velocity fields, phase-locked with the blade rotational motion, are acquired across several planes perpendicular to the blade axis and merged to form a 3D measurement volume. Transonic conditions have been reached at the tip region, with a revolution frequency of 19,800 rpm and a relative free-stream Mach number of 0.73 at the tip. The pressure field and the surface pressure distribution are inferred from the 3D velocity data through integration of the momentum Navier-Stokes equation in differential form, allowing for the simultaneous flow visualization and the aerodynamic loads computation, with respect to a reference frame moving with the blade. The momentum and pressure data are further integrated by means of a contour-approach to yield the aerodynamic sectional force components as well as the blade torsional moment. A steady Reynolds averaged Navier-Stokes numerical simulation of the entire propeller model has been used for comparison to the measurement data. (orig.)

  19. An investigation of an active landing gear system to reduce aircraft vibrations caused by landing impacts and runway excitations

    Science.gov (United States)

    Wang, Haitao; Xing, J. T.; Price, W. G.; Li, Weiji

    2008-10-01

    A mathematical model is developed to control aircraft vibrations caused by runway excitation using an active landing gear system. Equations are derived to describe the integrated aircraft-active system. The nonlinear characteristics of the system are modelled and it is actively controlled using a Proportional Integral Derivative (PID) strategy. The performance of this system and its corresponding passive system are compared using numerical simulations. It is demonstrated that the impact loads and the vertical displacement of the aircraft's centre of gravity caused by landing and runway excitations are greatly reduced using the active system, which result in improvements to the performance of the landing gear system, benefits the aircraft's fatigue life, taxiing performance, crew/passenger comfort and reduces requirements on the unevenness of runways.

  20. Fuzzy Q learning algorithm for dual-aircraft path planning to cooperatively detect targets by passive radars

    Institute of Scientific and Technical Information of China (English)

    Xiang Gao; Yangwang Fang; Youli Wu

    2013-01-01

    The problem of passive detection discussed in this paper involves searching and locating an aerial emitter by dual-aircraft using passive radars. In order to improve the detection probability and accuracy, a fuzzy Q learning algorithm for dual-aircraft flight path planning is proposed. The passive detection task model of the dual-aircraft is set up based on the partition of the target active radar’s radiation area. The problem is formulated as a Markov decision process (MDP) by using the fuzzy theory to make a generalization of the state space and defining the transition functions, action space and reward function properly. Details of the path planning algorithm are presented. Simulation results indicate that the algorithm can provide adaptive strategies for dual-aircraft to control their flight paths to detect a non-maneuvering or maneu-vering target.

  1. Hot gas ingestion testing of an advanced STOVL concept in the NASA Lewis 9- by 15-foot Low Speed Wind Tunnel with flow visualization

    Science.gov (United States)

    Johns, Albert L.; Flood, Joseph D.; Strock, Thomas W.; Amuedo, Kurt C.

    1988-01-01

    Advanced Short Takeoff/Vertical Landing (STOVL) aircraft capable of operating from remote sites, damaged runways, and small air capable ships are being pursued for deployment around the turn of the century. To achieve this goal, it is important that the technologies critical to this unique class of aircraft be developed. Recognizing this need, NASA Lewis Research Center, McDonnell Douglas Aircraft, and DARPA defined a cooperative program for testing in the NASA Lewis 9- by 15-foot Low Speed Wind Tunnel (LSWT) to establish a database for hot gas ingestion, one of the technologies critical to STOVL. Results from a test program are presented along with a discussion of the facility modifications allowing this type of testing at modal scale. These modifications to the tunnel include a novel ground plane, an elaborate model support which included 4 degrees of freedom, heated high pressure air for nozzle flow, a suction system exhaust for inlet flow, and tunnel sidewall modifications. Several flow visualization techniques were employed including water mist in the nozzle flows and tufts on the ground plane. Headwind (free-stream) velocity was varied from 8 to 23 knots.

  2. Improving the Response of a Wheel Speed Sensor by Using a RLS Lattice Algorithm

    Directory of Open Access Journals (Sweden)

    Wilmar Hernandez

    2006-02-01

    Full Text Available Among the complete family of sensors for automotive safety, consumer andindustrial application, speed sensors stand out as one of the most important. Actually, speedsensors have the diversity to be used in a broad range of applications. In today’s automotiveindustry, such sensors are used in the antilock braking system, the traction control systemand the electronic stability program. Also, typical applications are cam and crank shaftposition/speed and wheel and turbo shaft speed measurement. In addition, they are used tocontrol a variety of functions, including fuel injection, ignition timing in engines, and so on.However, some types of speed sensors cannot respond to very low speeds for differentreasons. What is more, the main reason why such sensors are not good at detecting very lowspeeds is that they are more susceptible to noise when the speed of the target is low. In short,they suffer from noise and generally only work at medium to high speeds. This is one of thedrawbacks of the inductive (magnetic reluctance speed sensors and is the case under study.Furthermore, there are other speed sensors like the differential Hall Effect sensors that arerelatively immune to interference and noise, but they cannot detect static fields. This limitstheir operations to speeds which give a switching frequency greater than a minimumoperating frequency. In short, this research is focused on improving the performance of avariable reluctance speed sensor placed in a car under performance tests by using arecursive least-squares (RLS lattice algorithm. Such an algorithm is situated in an adaptivenoise canceller and carries out an optimal estimation of the relevant signal coming from thesensor, which is buried in a broad-band noise background where we have little knowledgeof the noise characteristics. The experimental results are satisfactory and show a significantimprovement in the signal-to-noise ratio at the system output.

  3. Penetrating injury of the lungs and multiple injuries of lower extremities caused by aircraft bombs splinters

    Directory of Open Access Journals (Sweden)

    Golubović Zoran

    2010-01-01

    Full Text Available Introduction. Injuries caused by aircraft bombs cause severe damages to the human body. They are characterized by massive destruction of injured tissues and organs, primary contamination by polymorph bacterial flora and modified reactivity of the body. Upon being wounded by aircraft bombs projectiles a victim simultaneously sustains severe damages of many organs and organ systems due to the fact that a large number of projectiles at the same time injure the chest, stomach, head and extremities. Case report. We presented a patient, 41 years of age, injured by aircraft bomb with hemo-pneumothorax and destruction of the bone and soft tissue structures of the foot, as well as the treatment result of such heavy injuries. After receiving thoracocentesis and short reanimation, the patient underwent surgical procedure. The team performed thoracotomy, primary treatment of the wound and atypical resection of the left lung. Thoracic drains were placed. The wounds on the lower leg and feet were treated primarily. Due to massive destruction of bone tissue of the right foot by cluster bomb splinters, and impossibility of reconstruction of the foot, guillotine amputation of the right lower leg was performed. Twelve days after the wounding caused by cluster bomb splinters, soft tissue of the left lower leg was covered by Tirsch free transplantant and the defect in the area of the left foot was covered by dorsalis pedis flap. The transplant and flap were accepted and the donor sites were epithelized. Twenty-six days following the wounding reamputation was performed and amputation stump of the right lower leg was closed. The patient was given a lower leg prosthesis with which he could move. Conclusion. Upon being wounded by aircraft bomb splinters, the injured person sustains severe wounds of multiple organs and organ systems due to simultaneous injuries caused by a large number of projectiles. It is necessary to take care of the vital organs first because they

  4. Anticipated Effectiveness of Active Noise Control in Propeller Aircraft Interiors as Determined by Sound Quality Tests

    Science.gov (United States)

    Powell, Clemans A.; Sullivan, Brenda M.

    2004-01-01

    Two experiments were conducted, using sound quality engineering practices, to determine the subjective effectiveness of hypothetical active noise control systems in a range of propeller aircraft. The two tests differed by the type of judgments made by the subjects: pair comparisons in the first test and numerical category scaling in the second. Although the results of the two tests were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference.

  5. ZnS thin film deposited with chemical bath deposition process directed by different stirring speeds

    Science.gov (United States)

    Zhang, Y.; Dang, X. Y.; Jin, J.; Yu, T.; Li, B. Z.; He, Q.; Li, F. Y.; Sun, Y.

    2010-09-01

    In this combined film thickness, scanning electron microscopy (SEM), X-ray diffraction and optical properties study, we explore the effects of different stirring speeds on the growth and optical properties of ZnS film deposited by CBD method. From the disclosed changes of thickness of ZnS film, we conclude that film thickness is independent of the stirring speeds in the heterogeneous process (deposition time less than 40 min), but increases with the stirring speeds and/or deposition time increasing in the homogeneous process. Grazing incident X-ray diffraction (GIXRD) and the study of optical properties disclosed that the ZnS films grown with different stirring speeds show partially crystallized film and exhibit good transmittance (70-88% in the visible region), but the stirring speeds cannot give much effects on the structure and optical properties in the homogeneous process.

  6. Rain-aerosol relationships influenced by wind speed: RAIN-AEROSOL RELATIONSHIPS

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yang [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Russell, Lynn M. [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Lou, Sijia [Scripps Institution of Oceanography, University of California, San Diego, La Jolla California USA; Liu, Ying [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Singh, Balwinder [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Ghan, Steven J. [Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA

    2016-03-08

    The aerosol optical depth (AOD) has been shown to correlate with precipitation rate (R) in recent studies. The relationships between R and AOD are examined in this study using 150-year simulations in preindustrial conditions with the CESM model. Through partial correlation analysis, with the impact from 10-m wind speed removed, relationships between modeled AOD and R exert a significant change from positive to negative over the mid-latitude oceans, indicating that the wind speed has the largest contribution to the relationships over the mid-latitude oceans. Sensitivity simulation shows that variations in wind speed lead to increasing R by +0.99 mm day-1 averaged globally, offsetting 64% of the wet scavenging induced decrease in precipitation between polluted and clean conditions. These demonstrate that wind speed is one of the major drivers of R-AOD relationships. Relative humidity can also result in the positive relationships; however, its role is smaller than that of wind speed.

  7. Sensorless speed estimation of an AC induction motor by using an artificial neural network approach

    Science.gov (United States)

    Alkhoraif, Abdulelah Ali

    Sensorless speed detection of an induction motor is an attractive area for researchers to enhance the reliability of the system and to reduce the cost of the components. This paper presents a simple method of estimating a rotational speed by utilizing an artificial neural network (ANN) that would be fed by a set of stator current frequencies that contain some saliency harmonics. This approach allows operators to detect the speed in induction motors such an approach also provides reliability, low cost, and simplicity. First, the proposed method is based on converting the stator current signals to the frequency domain and then applying a tracking algorithm to the stator current spectrum in order to detect frequency peaks. Secondly, the ANN has to be trained by the detected peaks; the training data must be from very precise data to provide an accurate rotor speed. Moreover, the desired output of the training is the speed, which is measured by a tachometer simultaneously with the stator current signal. The databases were collected at many different speeds from two different types of AC induction motors, wound rotor and squirrel cage. They were trained and tested, so when the difference between the desired speed value and the ANN output value reached the wanted accuracy, the system does not need to use the tachometer anymore. Eventually, the experimental results show that in an optimal ANN design, the speed of the wound rotor induction motor was estimated accurately, where the testing average error was 1 RPM. The proposed method has not succeeded to predict the rotor speed of the squirrel cage induction motor precisely, where the smallest testing­average error that was achieved was 5 RPM.

  8. Chemistry Characterization of Jet Aircraft Engine Particulate by XPS: Results from APEX III

    Science.gov (United States)

    Vander Wal, Randy L.; Bryg, Victoria M.

    2014-01-01

    This paper reports XPS analysis of jet exhaust particulate from a B737, Lear, ERJ, and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and platforms. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20 percent or more. By lower resolution survey scans various elements including transition metals are identified along with lighter elements such as S, N, and O in the form of oxides. Burning additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their presence can be used as a tracer for identifying soots from aircraft engines as well as diagnostic for monitoring engine performance and wear.

  9. Chemistry characterization of jet aircraft engine particulate matter by XPS: Results from APEX III

    Science.gov (United States)

    Vander Wal, Randy L.; Bryg, Victoria M.; Huang, Chung-Hsuan

    2016-09-01

    This paper reports X-ray photoelectron spectroscopy (XPS) analysis of jet exhaust particulate matter (PM) from a B737, Lear, ERJ and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and powers. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20% or more. By survey scans various elements including transition metals are identified along with lighter elements such as S, N and O in the form of oxides. Additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their collective presence could serve as an environmental tracer for identifying PM originating from aircraft engines and serving as a diagnostic for engine performance and wear.

  10. Determine an effective golf swing by swing speed and impact precision tests

    Institute of Scientific and Technical Information of China (English)

    Jiann-Jyh Wang; Pei-Feng Yang; Wei-Hua Ho; Tzyy-Yuang Shiang

    2015-01-01

    Background:To understand an effective golf swing, both swing speed and impact precision must be thoroughly and simultaneously examined. The aim of this study was to perform both swing speed test and impact precision test to ascertain what swing type determines an effective impact. Methods:Seven golfers from a college team (handicap:0-12) were recruited to complete a swing speed test and impact precision test using a 5-iron club. A force plate and electromyography (EMG) system were used to collect data in the swing speed test to compare the difference between two motion sequences. High speed video cameras were used to determine the displacement of rotation center for impact precision test. Results: The results showed a significant difference ( p < 0.01) in clubhead speed with different motion sequences and muscle contraction patterns. In the impact precision test, the displacement of the rotation center which defined as the inner center point of the C7 was significantly different ( p<0.05) between different ball impacted marks on club face. Conclusion:The vertical peak ground reaction force on left foot occurring before impact and the left latissimus dorsi contracting prior to the right pectoralis major represent a superior skill by allowing the club to strike the ball with normal collision at a faster speed.

  11. The characteristics of machined surface controlled by multi tip arrayed tool and high speed spindle.

    Science.gov (United States)

    Kim, Yong Woo; Choi, Soo Chang; Park, Jeong Woo; Lee, Deug Woo

    2010-07-01

    In this study, we propose one of the ultra-precision machining methods that can be adapted brittle material as well as soft material by using multi arrayed diamond tips and high speed spindle. Conventional machining method is too hard to control surface roughness and surface texture against brittle material because particles of grinding tools are irregular size and material can be fragile. Therefore we were able to design tool paths and machine controlled pattern on surface by multi arrayed diamond tips which has uniform size made in MEMS fabrication and high speed spindle of which maximum speed is about 300,000 rpm. We defined several parameters that can have effect on machining surface. Those are multi array of diamond tips (n * n), speed of the air spindle, and feeding rate. Surface roughness and surface texture can be controlled by those parameters for micro machining.

  12. Intensive probing of a clear air convective field by radar and instrumental drone aircraft.

    Science.gov (United States)

    Rowland, J. R.

    1973-01-01

    An instrumented drone aircraft was used in conjunction with ultrasensitive radar to study the development of a convective field in the clear air. Radar data are presented which show an initial constant growth rate in the height of the convective field of 3.8 m/min, followed by a short period marked by condensation and rapid growth at a rate in excess of 6.1 m/min. Drone aircraft soundings show general features of a convective field including progressive lifting of the inversion at the top of the convection and a cooling of the air at the top of the field. Calculations of vertical heat flux as a function of time and altitude during the early stages of convection show a linear decrease in heat flux with altitude to near the top of the convective field and a negative heat flux at the top. Evidence is presented which supports previous observations that convective cells overshoot their neutral buoyancy level into a region where they are cool and moist compared to their surroundings. Furthermore, only that portion of the convective cell that has overshot its neutral buoyancy level is generally visible to the radar.

  13. Evaluation of the doses to aircrew members by considering the aircraft structures

    Science.gov (United States)

    Battistoni, G.; Ferrari, A.; Pelliccioni, M.; Villari, R.

    A mathematical model of an aircraft has been developed with the aim to investigate the influence of the aircraft structures and contents on the exposure of aircrew and passengers to the galactic component of cosmic rays. The irradiation of the mathematical model in the cosmic ray environment has been simulated using the Monte Carlo transport code FLUKA. Effective dose and ambient dose equivalent rates have been determined inside the aircraft at several locations along the fuselage at typical civil aviation altitudes.

  14. Formation and evolution of a hairpin vortex induced by subharmonic sinuous low-speed streaks

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian; Dong, Gang; Lu, Ziheng, E-mail: dgvehicle@yahoo.com [State Key Laboratory of Transient Physics, Nanjing University of Science and Technology, Nanjing, 210094, Jiangsu Province, People’s Republic of China (China)

    2014-10-01

    In this paper, a process of the formation and evolution of hairpin vortices, which originated from the interaction between the spanwise-aligned low-speed streaks with a subharmonic sinuous (SS) oscillation mode, is studied using a direct numerical simulation method in a small periodic local region of an incompressible plane channel flow. The initial artificial perturbations are used to excite the SS-mode oscillation of two spanwise-aligned low-speed streaks in such a flow. A new mechanism of formation and decay of the hairpin vortices is proposed in which the shear layer induced by the spanwise collision and merging between the low-speed streaks is emphasized. Our results show that the streamwise vortices can be induced by the SS-mode streaks and then developed into an X-like pattern at the initial stage due to the mutual induction effect. The X-like vortices further enhance the spanwise oscillation and lift-up of the two streaks that thus lead to the spanwise collision and merging of the low-speed streaks and produce a low-speed region in high-speed fluid. The strong shear layer between the high- and low-speed fluids gives rise to the spanwise vorticity that connects the X-like streamwise vortices and forms the Λ-like vortex. Once the low-speed region entirely enters the high-speed fluid, the shear layer shows the ring shape and results in the transition from a Λ-like vortex to Ω-like one. After that, the viscous diffusion of the low-speed region in the high-speed fluid leads to the decay of the Ω-like vortex; the collision and merging of the low-speed streaks simultaneously reoccur upstream and give birth to a secondary Λ-like vortex, which exhibits behavior that is nearly similar with that of the primary one. Although the hairpin vortex packet is not observed in the present plane channel flow, the regeneration of the hairpin vortex suggests that this type of vortical structure plays an important role in the wall-bounded flow. (paper)

  15. Pitch link loads reduction of variable speed rotors by variable tuning frequency fluidlastic isolators

    Directory of Open Access Journals (Sweden)

    Han Dong

    2015-10-01

    Full Text Available To reduce the pitch link loads of variable speed rotors, variable tuning frequency fluidlastic isolators are proposed. This isolator utilizes the variation of centrifugal force due to the change of rotor speed to change the tuning port area ratio, which can change the tuning frequency of the isolator. A rotor model including the model of fluidlastic isolator is coupled with a fuselage model to predict the steady responses of the rotor system in forward flight. The aeroelastic analyses indicate that distinct performance improvement in pitch link load control can be achieved by the utilization of variable frequency isolators compared with the constant tuning frequency isolators. The 4/rev (per revolution pitch link load is observed to be reduced by 87.6% compared with the increase of 56.3% by the constant frequency isolator, when the rotor speed is reduced by 16.7%. The isolation ability at different rotor speeds in different flight states is investigated. To achieve overall load reduction within the whole range of rotor speed, the strategy of the variation of tuning frequency is adjusted. The results indicate that the 4/rev pitch link load within the whole rotor speed range is decreased.

  16. Pitch link loads reduction of variable speed rotors by variable tuning frequency fluidlastic isolators

    Institute of Scientific and Technical Information of China (English)

    Han Dong

    2015-01-01

    To reduce the pitch link loads of variable speed rotors, variable tuning frequency fluid-lastic isolators are proposed. This isolator utilizes the variation of centrifugal force due to the change of rotor speed to change the tuning port area ratio, which can change the tuning frequency of the isolator. A rotor model including the model of fluidlastic isolator is coupled with a fuselage model to predict the steady responses of the rotor system in forward flight. The aeroelastic analyses indicate that distinct performance improvement in pitch link load control can be achieved by the utilization of variable frequency isolators compared with the constant tuning frequency isolators. The 4/rev (per revolution) pitch link load is observed to be reduced by 87.6%compared with the increase of 56.3%by the constant frequency isolator, when the rotor speed is reduced by 16.7%. The isolation ability at different rotor speeds in different flight states is investigated. To achieve overall load reduction within the whole range of rotor speed, the strategy of the variation of tuning frequency is adjusted. The results indicate that the 4/rev pitch link load within the whole rotor speed range is decreased.

  17. Speeding disease gene discovery by sequence based candidate prioritization

    Directory of Open Access Journals (Sweden)

    Porteous David J

    2005-03-01

    Full Text Available Abstract Background Regions of interest identified through genetic linkage studies regularly exceed 30 centimorgans in size and can contain hundreds of genes. Traditionally this number is reduced by matching functional annotation to knowledge of the disease or phenotype in question. However, here we show that disease genes share patterns of sequence-based features that can provide a good basis for automatic prioritization of candidates by machine learning. Results We examined a variety of sequence-based features and found that for many of them there are significant differences between the sets of genes known to be involved in human hereditary disease and those not known to be involved in disease. We have created an automatic classifier called PROSPECTR based on those features using the alternating decision tree algorithm which ranks genes in the order of likelihood of involvement in disease. On average, PROSPECTR enriches lists for disease genes two-fold 77% of the time, five-fold 37% of the time and twenty-fold 11% of the time. Conclusion PROSPECTR is a simple and effective way to identify genes involved in Mendelian and oligogenic disorders. It performs markedly better than the single existing sequence-based classifier on novel data. PROSPECTR could save investigators looking at large regions of interest time and effort by prioritizing positional candidate genes for mutation detection and case-control association studies.

  18. As time goes by: Studies on the subjective perception of the speed by which time passes

    NARCIS (Netherlands)

    Li, X.

    2015-01-01

    This thesis deals with an overlooked dimension of time judgments, namely subjective judgments of the speed of time passage: how fast time is judged as passing. It has examined how people make judgments of the speed of time passage and what factors influence people’s judgments of the speed of time pa

  19. Increasing titration speed by using an end paint anticipator device

    OpenAIRE

    2001-01-01

    A simple device is described for use in any titrations with the objective of rapidly locating the vicinity of the end point of a titration. The device stores inside about 10% of a 10 mL titrand solution. The titration itself proceeds with rapid addition of titrant until the end point is passed. The anticipator device now starts to rotate, using a dc motor, which is turned on by a micro-computer. The solution stored in the device is mixed with the already titrated solution and the property bei...

  20. Rotor speed estimation of induction machines by monitoring the stator voltages and currents

    Energy Technology Data Exchange (ETDEWEB)

    Ho, S.Y.S.; Langman, R.A. [Tasmania Univ., Hobart, TAS (Australia)

    1995-12-31

    Accurate measurement of induction motor speed is routinely obtained by using a transducer coupled on the shaft. In many industrial situations, this is not acceptable as there may be no room for a suitable transducer, or else the motor environment may be too unpleasant. It is in theory possible to calculate the speed by monitoring the terminal voltages and currents (plus knowing the angular synchronous speed) and then applying these to the differential equations of motor. Two rotor speed algorithms were investigated. Unsatisfactory results were obtained with an algorithm based on the machine equations in a stationary reference frame because at some stage the algorithm divides zero by zero. To avoid these problems the time varying stator voltages and currents were further transformed into the synchronous reference frame so that they end up with dc electrical quantities. This algorithm of obtaining the tangent of the phase angle, for the determination of the rotor speed, was discussed and tested. The analysis presented in this paper points out that the speed of induction motor may be estimated at about +- 0.1 percent uncertainty from measurement of the stator voltage and current. (author). 5 figs., 5 refs.

  1. Children's Brain Responses to Optic Flow Vary by Pattern Type and Motion Speed.

    Directory of Open Access Journals (Sweden)

    Rick O Gilmore

    Full Text Available Structured patterns of global visual motion called optic flow provide crucial information about an observer's speed and direction of self-motion and about the geometry of the environment. Brain and behavioral responses to optic flow undergo considerable postnatal maturation, but relatively little brain imaging evidence describes the time course of development in motion processing systems in early to middle childhood, a time when psychophysical data suggest that there are changes in sensitivity. To fill this gap, electroencephalographic (EEG responses were recorded in 4- to 8-year-old children who viewed three time-varying optic flow patterns (translation, rotation, and radial expansion/contraction at three different speeds (2, 4, and 8 deg/s. Modulations of global motion coherence evoked coherent EEG responses at the first harmonic that differed by flow pattern and responses at the third harmonic and dot update rate that varied by speed. Pattern-related responses clustered over right lateral channels while speed-related responses clustered over midline channels. Both children and adults show widespread responses to modulations of motion coherence at the second harmonic that are not selective for pattern or speed. The results suggest that the developing brain segregates the processing of optic flow pattern from speed and that an adult-like pattern of neural responses to optic flow has begun to emerge by early to middle childhood.

  2. Vehicle Vibration Analysis in Changeable Speeds Solved by Pseudoexcitation Method

    Directory of Open Access Journals (Sweden)

    Li-Xin Guo

    2010-01-01

    Full Text Available The vehicle driving comfort has become one of the important factors of vehicle quality and receives increasing attention. In this paper, the mechanical and mathematical models of the half-car, five degrees of freedom (DOF of a vehicle were established, as well as the pseudoexcitation model of road conditions for the front wheel and the rear wheel. By the pseudoexcitation method, the equations of transient response and power spectrum density were established. After numerical simulation to vehicle vibration response of changeable driving, the results show that the pseudoexcitation method is more convenient than the traditional method and effectively solves the smoothness computation problems of vehicles while the pseudoexcitation method is used to analyze vehicle vibration under nonstationary random vibration environments.

  3. Sensorless Speed Control of Permanent Magnet Synchronous Motors by Neural Network Algorithm

    Directory of Open Access Journals (Sweden)

    Ming-Shyan Wang

    2014-01-01

    Full Text Available The sliding mode control has the merits with respect to the variation of the disturbance and robustness. In this paper, the sensorless sliding-mode observer with least mean squared error approach for permanent magnet synchronous motor (PMSM to detect the rotor position by counter electromotive force and then compute motor speed is designed and implemented. In addition, the neural network control is also used to compensate the PI gain tuning to increase the speed accuracy without regarding the errors of the current measurement and motor noise. In this paper, a digital signal processor TMS320F2812 utilizes its high-speed ADC module to get current feedback information and thus to estimate the rotor position and takes advantage of the built-in modules to achieve SVPWM current control so that the senseless speed control will be accomplished. The correctness and effectiveness of the proposed control system will be verified from the experimental results.

  4. A second-generation high speed civil transport: Stingray

    Science.gov (United States)

    Engdahl, Sean; Lopes, Kevin; Ngan, Angelen; Perrin, Joseph; Phipps, Marcus; Westman, Blake; Yeo, Urn

    1992-01-01

    The Stingray is the second-generation High Speed Civil Transport (HSCT) designed for the 21st Century. This aircraft is designed to be economically viable and environmentally sound transportation competitive in markets currently dominated by subsonic aircraft such as the Boeing 747 and upcoming McDonnell Douglas MD-12. With the Stringray coming into service in 2005, a ticket price of 21 percent over current subsonic airlines will cover operational costs with a 10 percent return on investment. The cost per aircraft will be $202 million with the Direct Operating Cost equal to $0.072 per mile per seat. This aircraft has been designed to be a realistic aircraft that can be built within the next ten to fifteen years. There was only one main technological improvement factor used in the design, that being for the engine specific fuel consumption. The Stingray, therefore, does not rely on technology that does not exist. The Stingray will be powered by four mixed flow turbofans that meet both nitrous oxide emissions and FAR 36 Stage 3 noise regulations. It will carry 250 passengers a distance of 5200 nautical miles at a speed of Mach 2.4. The shape of the Stingray, while optimized for supersonic flight, is compatible with all current airline facilities in airports around the world. As the demand for economical, high-speed flight increases, the Stingray will be ready and able to meet those demands.

  5. Improving the Accuracy of Wind Turbine Power Curve Validation by the Rotor Equivalent Wind Speed Concept

    Science.gov (United States)

    Scheurich, Frank; Enevoldsen, Peder B.; Paulsen, Henrik N.; Dickow, Kristoffer K.; Fiedel, Moritz; Loeven, Alex; Antoniou, Ioannis

    2016-09-01

    The measurement of the wind speed at hub height is part of the current IEC standard procedure for the power curve validation of wind turbines. The inherent assumption is thereby made that this measured hub height wind speed sufficiently represents the wind speed across the entire rotor area. It is very questionable, however, whether the hub height wind speed (HHWS) method is appropriate for rotor sizes of commercial state-of-the-art wind turbines. The rotor equivalent wind speed (REWS) concept, in which the wind velocities are measured at several different heights across the rotor area, is deemed to be better suited to represent the wind speed in power curve measurements and thus results in more accurate predictions of the annual energy production (AEP) of the turbine. The present paper compares the estimated AEP, based on HHWS power curves, of two different commercial wind turbines to the AEP that is based on REWS power curves. The REWS was determined by LiDAR measurements of the wind velocities at ten different heights across the rotor area. It is shown that a REWS power curve can, depending on the wind shear profile, result in higher, equal or lower AEP estimations compared to the AEP predicted by a HHWS power curve.

  6. Aircraft Fuel Systems Career Ladder.

    Science.gov (United States)

    1985-09-01

    type fittings remove and install fuel cells clean work areas inspect aircraft for safety pin installation purge tanks or cells using blow purge method...INSPECT AIRCRAFT FOR SAFETY PIN INSTALLATION 84 H254 PURGE TANKS OR CELLS USING BLOW PURGE METHOD 83 H227 CHECK AIRCRAFT FOR LIQUID OXYGEN (LOX...H243 INSPECT AIRCRAFT FOR SAFETY PIN INSTALLATION 52 M483 MIX SEALANTS BY HAND 48 K372 CONNECT OR DISCONNECT WIGGINS TYPE FITTINGS 48 H236 DISCONNECT

  7. The stable isotopic composition of molecular hydrogen in the tropopause region probed by the CARIBIC aircraft

    Science.gov (United States)

    Batenburg, A. M.; Schuck, T. J.; Baker, A. K.; Zahn, A.; Brenninkmeijer, C. A. M.; Röckmann, T.

    2012-05-01

    More than 450 air samples that were collected in the upper troposphere - lower stratosphere (UTLS) region by the CARIBIC aircraft (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) have been analyzed for molecular hydrogen (H2) mixing ratios (χ(H2)) and H2 isotopic composition (deuterium content, δD). More than 120 of the analyzed samples contained air from the lowermost stratosphere (LMS). These show that χ(H2) does not vary appreciably with O3-derived height above the thermal tropopause (TP), whereas δD does increase with height. The isotope enrichment is caused by H2 production and destruction processes that enrich the stratospheric H2 reservoir in deuterium (D); the exact shapes of the profiles are mainly determined by mixing of stratospheric with tropospheric air. Tight negative correlations are found between δD and the mixing ratios of methane (χ(CH4)) and nitrous oxide (χ(N2O)), as a result of the relatively long lifetimes of these three species. The correlations are described by δD[‰]=-0.35 · χ(CH4)[ppb]+768 and δD[‰]=-1.90· χ(N2O)[ppb]+745. These correlations are similar to previously published results and likely hold globally for the LMS. Samples that were collected from the Indian subcontinent up to 40° N before, during and after the summer monsoon season show no significant seasonal change in χ(H2), but δD is up to 12.3‰ lower in the July, August and September monsoon samples. This δD decrease is correlated with the χ(CH4) increase in these samples. The significant correlation with χ(CH4) and the absence of a perceptible χ(H2) increase that accompanies the δD decrease indicates that microbial production of very D-depleted H2 in the wet season may contribute to this phenomenon. Some of the samples have very high χ(H2) and very low δD values, which indicates a pollution effect. Aircraft engine exhaust plumes are a suspected cause, since the effect mostly occurs in samples

  8. WHIPICE. [Computer Program for Analysis of Aircraft Deicing

    Science.gov (United States)

    1992-01-01

    This video documents efforts by NASA Lewis Research Center researchers to improve ice protection for aircraft. A new system of deicing aircraft by allowing a thin sheet of ice to develop, then breaking it into particles, is being examined, particularly to determine the extent of shed ice ingestion by jet engines that results. The process is documented by a high speed imaging system that scans the breakup and flow of the ice particles at 1000 frames per second. This data is then digitized and analyzed using a computer program called WHIPICE, which analyzes grey scale images of the ice particles. Detailed description of the operation of this computer program is provided.

  9. Speed control of synchronous machine by changing duty cycle of DC/DC buck converter

    Directory of Open Access Journals (Sweden)

    Rashid Al Badwawi

    2015-11-01

    Full Text Available Renewable energies such as wind or solar energy are naturally intermittent and can create technical challenges to interconnected grid in particular with high integration amounts. In addition, if wind or solar is used to supply power to a stand-alone system, continuous power supply will be met only if sufficient energy storage system is available. The global penetration of renewable energy in power systems is increasing rapidly especially wind and solar photovoltaic (PV systems. Hybrid wind and solar PV generation system becomes very attractive solution in particular for stand-alone applications. It can provide better reliability since the weakness of one system could be complemented by the strength of the other one. When wind energy is integrated into grid, maximum power point tracking control could be used to optimize the output of wind turbine. In variable speed wind turbine, the turbine speed is varied according to the wind speed. This paper presents a comparison between two methods of controlling the speed of a wind turbine in a microgrid namely; Proportional-Integral (PI control of the tip speed ratio and stored power curve. The PI method provides more controllability, but it requires an anemometer to measure the wind speed. The stored power curve method, however, is easier to implement, but the amount of energy extracted can be less. The system has been modelled using Matlab/Simulink.

  10. The influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation.

    Directory of Open Access Journals (Sweden)

    Jícha M.

    2013-04-01

    Full Text Available The paper deals with instigation of influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation. CFD approach was used for investigation and model geometry was based on small aircraft cabin mock-up geometry. Model was also equipped by nine seats and five manikins that represent passengers. The air jet direction was observed for selected ambient environment parameters and several types of air duct geometry and influence of main air duct geometry on jets direction is discussed. The model was created in StarCCM+ ver. 6.04.014 software and polyhedral mesh was used.

  11. The influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation.

    Science.gov (United States)

    Fišer, J.; Jícha, M.

    2013-04-01

    The paper deals with instigation of influence of air duct geometry on air jet direction in aircraft cabin ventilated by mixing ventilation. CFD approach was used for investigation and model geometry was based on small aircraft cabin mock-up geometry. Model was also equipped by nine seats and five manikins that represent passengers. The air jet direction was observed for selected ambient environment parameters and several types of air duct geometry and influence of main air duct geometry on jets direction is discussed. The model was created in StarCCM+ ver. 6.04.014 software and polyhedral mesh was used.

  12. Topological structures of vortex flow on a flying wing aircraft, controlled by a nanosecond pulse discharge plasma actuator

    Science.gov (United States)

    Du, Hai; Shi, Zhiwei; Cheng, Keming; Wei, Dechen; Li, Zheng; Zhou, Danjie; He, Haibo; Yao, Junkai; He, Chengjun

    2016-06-01

    Vortex control is a thriving research area, particularly in relation to flying wing or delta wing aircraft. This paper presents the topological structures of vortex flow on a flying wing aircraft controlled by a nanosecond plasma dielectric barrier discharge actuator. Experiments, including oil flow visualization and two-dimensional particle image velocimetry (PIV), were conducted in a wind tunnel with a Reynolds number of 0.5 × 106. Both oil and PIV results show that the vortex can be controlled. Oil topological structures on the aircraft surface coincide with spatial PIV flow structures. Both indicate vortex convergence and enhancement when the plasma discharge is switched on, leading to a reduced region of separated flow.

  13. 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.

  14. Efficient super-resolution image reconstruction applied to surveillance video captured by small unmanned aircraft systems

    Science.gov (United States)

    He, Qiang; Schultz, Richard R.; Chu, Chee-Hung Henry

    2008-04-01

    The concept surrounding super-resolution image reconstruction is to recover a highly-resolved image from a series of low-resolution images via between-frame subpixel image registration. In this paper, we propose a novel and efficient super-resolution algorithm, and then apply it to the reconstruction of real video data captured by a small Unmanned Aircraft System (UAS). Small UAS aircraft generally have a wingspan of less than four meters, so that these vehicles and their payloads can be buffeted by even light winds, resulting in potentially unstable video. This algorithm is based on a coarse-to-fine strategy, in which a coarsely super-resolved image sequence is first built from the original video data by image registration and bi-cubic interpolation between a fixed reference frame and every additional frame. It is well known that the median filter is robust to outliers. If we calculate pixel-wise medians in the coarsely super-resolved image sequence, we can restore a refined super-resolved image. The primary advantage is that this is a noniterative algorithm, unlike traditional approaches based on highly-computational iterative algorithms. Experimental results show that our coarse-to-fine super-resolution algorithm is not only robust, but also very efficient. In comparison with five well-known super-resolution algorithms, namely the robust super-resolution algorithm, bi-cubic interpolation, projection onto convex sets (POCS), the Papoulis-Gerchberg algorithm, and the iterated back projection algorithm, our proposed algorithm gives both strong efficiency and robustness, as well as good visual performance. This is particularly useful for the application of super-resolution to UAS surveillance video, where real-time processing is highly desired.

  15. Standard Test Method for Stress-Corrosion of Titanium Alloys by Aircraft Engine Cleaning Materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method establishes a test procedure for determining the propensity of aircraft turbine engine cleaning and maintenance materials for causing stress corrosion cracking of titanium alloy parts. 1.2 The evaluation is conducted on representative titanium alloys by determining the effect of contact with cleaning and maintenance materials on tendency of prestressed titanium alloys to crack when subsequently heated to elevated temperatures. 1.3 Test conditions are based upon manufacturer's maximum recommended operating solution concentration. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see and .

  16. Jet aircraft engine exhaust emissions database development: Year 1990 and 2015 scenarios

    Science.gov (United States)

    Landau, Z. Harry; Metwally, Munir; Vanalstyne, Richard; Ward, Clay A.

    1994-01-01

    Studies relating to environmental emissions associated with the High Speed Civil Transport (HSCT) military jet and charter jet aircraft were conducted by McDonnell Douglas Aerospace Transport Aircraft. The report includes engine emission results for baseline 1990 charter and military scenario and the projected jet engine emissions results for a 2015 scenario for a Mach 1.6 HSCT charter and military fleet. Discussions of the methodology used in formulating these databases are provided.

  17. Aircraft measurements of O3, HNO3, and N2O in the winter Arctic lower stratosphere during the Stratosphere-Troposphere Experiment by Aircraft Measurements (STREAM) 1

    Science.gov (United States)

    Bregman, A.; van Velthoven, P. F. J.; Wienhold, F. G.; Fischer, H.; Zenker, T.; Waibel, A.; Frenzel, A.; Arnold, F.; Harris, G. W.; Bolder, M. J. A.; Lelieveld, J.

    1995-06-01

    Simultaneous in situ measurements of O3, HNO3, and N2O were performed in the Arctic (68°-74°N) lower stratosphere during February 1993 on board a Cessna Citation aircraft up to 12.5 km altitude, during the first Stratosphere-Troposphere Experiment by Aircraft Measurements (STREAM) campaign. Strong variations in the concentrations, distributions, and ratios of these trace gases were found from the maximum altitude down to the tropopause. Close to the tropopause, vortex air was present with relatively low N2O concentrations. The observed N2O-HNO3 relation agrees with earlier measurements of total nitrogen and N2O inside the vortex, suggesting subsidence of vortex air across the bottom of the vortex. This air also contained low O3 concentrations relative to N2O, indicating enhanced O3 loss by chemical reactions involving stratospheric particles. Based on trajectory calculations and assuming a potential temperature cooling rate of 0.6 K d-1, we estimate an O3 loss of 4-7 ppbv d-1 (0.9-1.2% d-1), in the Arctic lower stratosphere for the period January-February 1993. Air parcels originating from middle latitudes, containing relatively low O3 and N2O concentrations, may have originated from the vortex earlier in the winter. In addition, the results also show high HNO3 concentrations relative to O3 and N2O. Air parcels originating from high latitudes may have been enriched in HNO3 by sedimentation and evaporation of nitric acid containing particles, which would explain the relatively high HNO3 concentrations and HNO3/O3 ratios measured. Heterogeneous chemistry on sulfuric acid particles, probably enhanced in concentration by gravitational settling of the Pinatubo aerosol, is the most plausible explanation for the observed high HNO3 concentrations relative to N2O in air parcels originating from midlatitudes.

  18. Numerical investigation of piled raft foundation in mitigating embankment vibrations induced by high-speed trains

    Institute of Scientific and Technical Information of China (English)

    付强; 刘汉龙; 丁选明; 郑长杰

    2015-01-01

    A three-dimensional dynamic finite element model of track-ballast-embankment and piled raft foundation system is established. Dynamic response of a railway embankment to a high-speed train is simulated for two cases: soft ground improved by piled raft foundation, and untreated soft ground. The obtained results are compared both in time domain and frequency domain to evaluate the effectiveness of the ground improvement in mitigating the embankment vibrations induced by high-speed trains. The results show that ground improving methods can significantly reduce the embankment vibrations at all considered train speeds(36-432 km/h). The ground response to a moving load is dictated largely by the relationship between load speed and characteristic value of wave velocities of the ground medium. At low speeds, the ground response from a moving load is essentially quasi-static. That is, the displacements fields are essential the static fields under the load simply moving with it. For the soft ground, the displacement on the ballast surface is large at all observed train speeds. For the model case where the ground is improved by piled raft foundation, the peak displacement is reduced at all considered train speeds compared with the case without ground improvement. Based on the effect of energy-dissipating of ballast-embankment-ground system with damping, the train-induced vibration waves moving in ballast and embankment are trapped and dissipated, and thus the vibration amplitudes of dynamic displacement outside the embankment are significantly reduced. But for the vibration amplitude of dynamic velocity, the vibration waves in embankment are absorbed or reflected back, and the velocity amplitudes at the ballast and embankment surface are enhanced. For the change of the vibration character of embankment and ballast, the bearing capacity and dynamic character are improved. Therefore, both of the static and dynamic displacements are reduced by ground improvement; the dynamic

  19. Numerical investigation of piled raft foundation in mitigating embankment vibrations induced by high-speed trains

    Institute of Scientific and Technical Information of China (English)

    付强; 刘汉龙; 丁选明; 郑长杰

    2015-01-01

    A three-dimensional dynamic finite element model of track-ballast-embankment and piled raft foundation system is established. Dynamic response of a railway embankment to a high-speed train is simulated for two cases: soft ground improved by piled raft foundation, and untreated soft ground. The obtained results are compared both in time domain and frequency domain to evaluate the effectiveness of the ground improvement in mitigating the embankment vibrations induced by high-speed trains. The results show that ground improving methods can significantly reduce the embankment vibrations at all considered train speeds (36− 432 km/h). The ground response to a moving load is dictated largely by the relationship between load speed and characteristic value of wave velocities of the ground medium. At low speeds, the ground response from a moving load is essentially quasi-static. That is, the displacements fields are essential the static fields under the load simply moving with it. For the soft ground, the displacement on the ballast surface is large at all observed train speeds. For the model case where the ground is improved by piled raft foundation, the peak displacement is reduced at all considered train speeds compared with the case without ground improvement. Based on the effect of energy-dissipating of ballast-embankment-ground system with damping, the train-induced vibration waves moving in ballast and embankment are trapped and dissipated, and thus the vibration amplitudes of dynamic displacement outside the embankment are significantly reduced. But for the vibration amplitude of dynamic velocity, the vibration waves in embankment are absorbed or reflected back, and the velocity amplitudes at the ballast and embankment surface are enhanced. For the change of the vibration character of embankment and ballast, the bearing capacity and dynamic character are improved. Therefore, both of the static and dynamic displacements are reduced by ground improvement; the dynamic

  20. Protection by Face Masks against H1N1 Virus on Trans-Pacific Passenger Aircraft, 2009

    Centers for Disease Control (CDC) Podcasts

    2013-07-10

    Dr. Mike Miller reads an abridged version of the Emerging Infectious Diseases’ article, Protection by Face Masks against H1N1 Virus on Trans-Pacific Passenger Aircraft, 2009.  Created: 7/10/2013 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 7/11/2013.

  1. Improvement of walking speed prediction by accelerometry and altimetry, validated by satellite positioning.

    Science.gov (United States)

    Perrin, O; Terrier, P; Ladetto, Q; Merminod, B; Schutz, Y

    2000-03-01

    Activity monitors based on accelerometry are used to predict the speed and energy cost of walking at 0% slope, but not at other inclinations. Parallel measurements of body accelerations and altitude variation were studied to determine whether walking speed prediction could be improved. Fourteen subjects walked twice along a 1.3 km circuit with substantial slope variations (-17% to +17%). The parameters recorded were body acceleration using a uni-axial accelerometer, altitude variation using differential barometry, and walking speed using satellite positioning (DGPS). Linear regressions were calculated between acceleration and walking speed, and between acceleration/altitude and walking speed. These predictive models, calculated using the data from the first circuit run, were used to predict speed during the second circuit. Finally the predicted velocity was compared with the measured one. The result was that acceleration alone failed to predict speed (mean r = 0.4). Adding altitude variation improved the prediction (mean r = 0.7). With regard to the altitude/acceleration-speed relationship, substantial inter-individual variation was found. It is concluded that accelerometry, combined with altitude measurement, can assess position variations of humans provided inter-individual variation is taken into account. It is also confirmed that DGPS can be used for outdoor walking speed measurements, opening up new perspectives in the field of biomechanics.

  2. As time goes by: Studies on the subjective perception of the speed by which time passes

    OpenAIRE

    Li, X.

    2015-01-01

    This thesis deals with an overlooked dimension of time judgments, namely subjective judgments of the speed of time passage: how fast time is judged as passing. It has examined how people make judgments of the speed of time passage and what factors influence people’s judgments of the speed of time passage. Chapter 2 first unravels the cognitive processes that underlie judgments of the speed of time passage: the more attention is paid to non-temporal information, the faster time is judged as pa...

  3. General relativistic model for experimental measurement of the speed of propagation of gravity by VLBI

    CERN Document Server

    Kopeikin, S M; Kopeikin, Sergei; Fomalont, Ed

    2002-01-01

    A relativistic sub-picosecond model of gravitational time delay in radio astronomical observations is worked out and a new experimental test of general relativity is discussed in which the effect of retardation of gravity associated with its finite speed can be observed. As a consequence, the speed of gravity can be measured by differential VLBI observations. Retardation in propagation of gravity is a central part of the Einstein theory of general relativity which has not been tested directly so far. The idea of the proposed gravitational experiment is based on the fact that gravity in general relativity propagates with finite speed so that the deflection of light caused by the body must be sensitive to the ratio of the body's velocity to the speed of gravity. The interferometric experiment can be performed, for example, during the very close angular passage of a quasar by Jupiter. Due to the finite speed of gravity and orbital motion of Jupiter, the variation in its gravitational field reaches observer on Ea...

  4. Wind Speed Forecasting Based on FEEMD and LSSVM Optimized by the Bat Algorithm

    Directory of Open Access Journals (Sweden)

    Wei Sun

    2015-06-01

    Full Text Available Affected by various environmental factors, wind speed presents high fluctuation, nonlinear and non-stationary characteristics. To evaluate wind energy properly and efficiently, this paper proposes a modified fast ensemble empirical model decomposition (FEEMD-bat algorithm (BA-least support vector machines (LSSVM (FEEMD-BA-LSSVM model combined with input selected by deep quantitative analysis. The original wind speed series are first decomposed into a limited number of intrinsic mode functions (IMFs with one residual series. Then a LSSVM is built to forecast these sub-series. In order to select input from environment variables, Cointegration and Granger causality tests are proposed to check the influence of temperature with different leading lengths. Partial correlation is applied to analyze the inner relationships between the historical speeds thus to select the LSSVM input. The parameters in LSSVM are fine-tuned by BA to ensure the generalization of LSSVM. The forecasting results suggest the hybrid approach outperforms the compared models.

  5. Evaluation of travelling vortex speed by means of vortex tracking and dynamic mode decomposition

    Science.gov (United States)

    Hyhlík, Tomáš

    2016-06-01

    The article deals with the analysis of unsteady periodic flow field related to synthetic jet creation. The analyses are based on the data obtained using ANSYS Fluent solver. Numerical results are validated by hot wire anemometry data measured along the jet centerline. The speed of travelling vortex ring is evaluated by using vortex tracking method and by using dynamic mode decomposition method. Vortex identification is based on residual vorticity which allows identifying regions in the flow field where fluid particles perform the rotational motion. The regime of the synthetic jet with Re = 329 and S = 19.7 is chosen. Both the vortex tracking and the dynamic mode decomposition based vortex speed evaluation indicate an increase in the vortex speed close to the orifice and then decrease with maximum reaching almost one and half of orifice centerline velocity. The article contains extended version the article presented at the conference AEaNMiFMaE 2016.

  6. Field measurements and analyses of environmental vibrations induced by high-speed Maglev.

    Science.gov (United States)

    Li, Guo-Qiang; Wang, Zhi-Lu; Chen, Suwen; Xu, You-Lin

    2016-10-15

    Maglev, offers competitive journey-times compared to the railway and subway systems in markets for which distance between the stations is 100-1600km owing to its high acceleration and speed; however, such systems may have excessive vibration. Field measurements of Maglev train-induced vibrations were therefore performed on the world's first commercial Maglev line in Shanghai, China. Seven test sections along the line were selected according to the operating conditions, covering speeds from 150 to 430km/h. Acceleration responses of bridge pier and nearby ground were measured in three directions and analyzed in both the time and frequency domain. The effects of Maglev train speed on vibrations of the bridge pier and ground were studied in terms of their peak accelerations. Attenuation of ground vibration was investigated up to 30m from the track centerline. Effects of guideway configuration were also analyzed based on the measurements through two different test sections with same train speed of 300km/h. The results showed that peak accelerations exhibited a strong correlation with both train speed and distance off the track. Guideway configuration had a significant effect on transverse vibration, but a weak impact on vertical and longitudinal vibrations of both bridge pier and ground. Statistics indicated that, contrary to the commonly accepted theory and experience, vertical vibration is not always dominant: transverse and longitudinal vibrations should also be considered, particularly near turns in the track. Moreover, measurements of ground vibration induced by traditional high-speed railway train were carried out with the same testing devices in Bengbu in the Anhui Province. Results showed that the Maglev train generates significantly different vibration signatures as compared to the traditional high-speed train. The results obtained from this paper can provide good insights on the impact of Maglev system on the urban environment and the quality of human life

  7. Aircraft Design

    Science.gov (United States)

    Bowers, Albion H. (Inventor); Uden, Edward (Inventor)

    2016-01-01

    The present invention is an aircraft wing design that creates a bell shaped span load, which results in a negative induced drag (induced thrust) on the outer portion of the wing; such a design obviates the need for rudder control of an aircraft.

  8. Variable Geometry Aircraft Wing Supported by Struts And/Or Trusses

    Science.gov (United States)

    Melton, John E. (Inventor); Dudley, Michael R. (Inventor)

    2016-01-01

    The present invention provides an aircraft having variable airframe geometry for accommodating efficient flight. The aircraft includes an elongated fuselage, an oblique wing pivotally connected with said fuselage, a wing pivoting mechanism connected with said oblique wing and said fuselage, and a brace operably connected between said oblique wing and said fuselage. The present invention also provides an aircraft having an elongated fuselage, an oblique wing pivotally connected with said fuselage, a wing pivoting mechanism connected with said oblique wing and said fuselage, a propulsion system pivotally connected with said oblique wing, and a brace operably connected between said propulsion system and said fuselage.

  9. APPROACH OF IMPROVING PRECISION IN ULTRASONIC DOPPLER BLOODSTREAM SPEED MEASUREMENT BY CHAOS-BASED FREQUENCY DETECTING

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It is critical for cerebral vascular disease diagnosis through Doppler to detect the maximum and the minimum of the carotid blood flow speed accurately. A kind of Duffing system under an external periodic power with dump is introduced in the letter, numerical analysis is carried out by four-order Runge-Kutta method. An oscillator array is designed according to the frequency of the ultrasonic wave. When the external signals are inputted, computational algorithm is used to scan the array in turn and analyze the result, and the frequency can be determined. Based on the methods above, detecting the carotid blood flow speed accurately is realized. The Signal-to-Noise Ratio (SNR) of-20.23dB is obtained by the result of experiments. In conclusion, the SNR has been improved and the precision of the measured bloodstream speed has been increased,which can be 0.069% to 0.13%.

  10. Visualization of Aircraft Longitudinal-Axis Motion

    OpenAIRE

    Peter Kvasnica

    2015-01-01

    In this paper, the use of continuous mathematical models of an aircraft in an aircraft simulator is described. The models are of lower degree and less time-consuming for calculation. Computer implementation of the models capable to work faster and more accurately and efficiently is also described. The suggested approach allows to achieve the required precision at accelerated simulation speed using the continuous mathematical models of an aircraft. Frequency of the computation of continuous ma...

  11. Development and testing of advanced redundancy management methods for the F-8 DFBW aircraft. [failure detection for Digital Fly By Wire systems

    Science.gov (United States)

    Deyst, J.; Deckert, J.; Desai, M.; Willsky, A.

    1977-01-01

    A reliable aircraft sensor failure detection and identification (FDI) technique is presented. The technique exploits the kinematic and dynamic relationships that exist between variables measured by dissimilar sensors to identify failures in the sensors. The method is applied to management of dual redundant sensors on the NASA F-8 digital fly-by-wire (DFBW) research aircraft.

  12. Braking performance of aircraft tires

    Science.gov (United States)

    Agrawal, Satish K.

    This paper brings under one cover the subject of aircraft braking performance and a variety of related phenomena that lead to aircraft hydroplaning, overruns, and loss of directional control. Complex processes involving tire deformation, tire slipping, and fluid pressures in the tire-runway contact area develop the friction forces for retarding the aircraft; this paper describes the physics of these processes. The paper reviews the past and present research efforts and concludes that the most effective way to combat the hazards associated with aircraft landings and takeoffs on contaminated runways is by measuring and displaying in realtime the braking performance parameters in the aircraft cockpit.

  13. Upwind scheme for acoustic disturbances generated by low-speed flows

    DEFF Research Database (Denmark)

    Ekaterinaris, J.A.

    1997-01-01

    Computation of acoustic disturbances generated by unsteady, low-speed flows, such as flows including vortices and shear layers, can be obtained by a recently proposed two-step method. This method requires a hydrodynamic field solution and obtains the acoustic field from the perturbed, inviscid, c...

  14. Pitch Motion Stabilization by Propeller Speed Control Using Statistical Controller Design

    DEFF Research Database (Denmark)

    Nakatani, Toshihiko; Blanke, Mogens; Galeazzi, Roberto

    2006-01-01

    This paper describes dynamics analysis of a small training boat and a possibility of ship pitch stabilization by control of propeller speed. After upgrading the navigational system of an actual small training boat, in order to identify the model of the ship, the real data collected by sea trials...

  15. Thermal effects on human performance in office environment measured by integrating task speed and accuracy

    DEFF Research Database (Denmark)

    Lan, Li; Wargocki, Pawel; Lian, Zhiwei

    2014-01-01

    We have proposed a method in which the speed and accuracy can be integrated into one metric of human performance. This was achieved by designing a performance task in which the subjects receive feedback on their performance by informing them whether they have committed errors, and if did, they ca...

  16. Winter temperature, salinity, oxygen, nutrients and isotopes data sampled by aircraft, April 2003 (NODC Accession 0059129)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Winter sampling was performed in the eastern area of the Shelf-Basin Interactions Project using aircraft. Flights began on 1 April 2003 and finished on 15 April....

  17. Predicting Visibility of Aircraft

    Science.gov (United States)

    Watson, Andrew; Ramirez, Cesar V.; Salud, Ellen

    2009-01-01

    Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO). In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration. PMID:19462007

  18. Low speed axial compressor stall margin improvement by unsteady plasma actuation

    Science.gov (United States)

    Li, Gang; Xu, Yanji; Yang, Lingyuan; Du, Wei; Zhu, Junqiang; Nie, Chaoqun

    2014-04-01

    This research investigates the use of single dielectric barrier discharge (SDBD) actuators for energizing the tip leakage flow to suppress rotating stall inception and extend the stable operating range of a low speed axial compressor with a single rotor. The jet induced by the plasma actuator adds momentum to the flow in the tip region and has a significant impact on the tip-gap flow. Experiments are carried out on a low speed axial compressor with a single rotor. The static pressure is measured at both the rotor inlet and outlet. The flow coefficient and pressure rise coefficient are calculated. Then the characteristic line is acquired to show the overall performance of the compressor. With unsteady plasma actuation of 18kV and 60W the compressor stability range improvement is realized at rotor speed of 1500 r/min — 2400 r/min.

  19. Nuisance Caused by Aircraft Noise in the Vicinity of Tehran International Airport

    Directory of Open Access Journals (Sweden)

    Stan Frost

    1999-03-01

    Full Text Available Noise measurement and social questionnaire surveys in three residential areas around Mehrabad International Airport (Tehran, Iran were based upon randomly selected dwellings in each area. A total of 193 individuals responded and many are annoyed and dissatisfied with aircraft noise and in consequence they would like to move. Aircraft noise is the strongest negative environmental factor affecting the residents in the vicinity of Mehrabad Airport and it could be a hazard for their health.

  20. Determining the speed of multipartite quantum systems by few local measurements

    CERN Document Server

    Zhang, Chao; Hou, Zhi-Bo; Cao, Huan; Liu, Bi-Heng; Huang, Yun-Feng; Maity, Reevu; Vedral, Vlatko; Li, Chuan-Feng; Guo, Guang-Can; Girolami, Davide

    2016-01-01

    Measuring the speed of evolution of a quantum system can reveal its key properties and structure. Yet, it usually requires experimental and computational resources which increase exponentially with the system size. Here we show how to evaluate the speed of a multipartite quantum system by measurement networks scaling linearly with the system parts. We employ the scheme to detect fundamental quantum properties including metrologically useful coherence and entanglement in an all-optical experiment. The result paves the way for the investigation of quantum phenomena in large complex systems with limited resources.

  1. Flicker Mitigation by Individual Pitch Control of Variable Speed Wind Turbines With DFIG

    DEFF Research Database (Denmark)

    Zhang, Yunqian; Chen, Zhe; Hu, Weihao;

    2014-01-01

    generatorto investigate the flicker emission and mitigation issues. An individual pitch control (IPC) strategy is proposed to reduce the flicker emission at different wind speed conditions. The IPC scheme is proposed and the individual pitch controller is designed according to the generator active power...... and the azimuth angle of the wind turbine. The simulations are performed on the NREL (National Renewable Energy Laboratory) 1.5-MW upwind reference wind turbine model. Simulation results show that damping the generator active power by IPC is an effective means for flicker mitigation of variable speed wind...

  2. Measurement of metal vapor cooling speed during nanoparticle formation by pulsed wire discharge

    Institute of Scientific and Technical Information of China (English)

    Yuu SHIKODA; Yoshinori TOKOI; Koji SUWA; Satoru ISHIHARA; Tsuneo SUZUKI; Tadachika NAKAYAMA; Hisayuki SUEMATSU; Koichi NIIHARA

    2009-01-01

    Pulsed wire discharge(PWD) is one of nano-sized powder production methods. The object of this work is to study influence of the plasma/vapor/particle density using computer simulation and to establish temperature measurement method using a high-speed infrared thermometer in the PWD process. The temperature correction coefficient was obtained from geometric computer simulation results. Obtained correction coefficient was applied to the temperature measuring results. It was found from this result that obtained correction coefficient was appropriate. A temperature measurement method was established by using the high-speed infrared thermometer in PWD.

  3. The reconstruction of sound speed in the Marmousi model by the boundary control method

    CERN Document Server

    Ivanov, I B; Semenov, V S

    2016-01-01

    We present the results on numerical testing of the Boundary Control Method in the sound speed determination for the acoustic equation on semiplane. This method for solving multidimensional inverse problems requires no a priory information about the parameters under reconstruction. The application to the realistic Marmousi model demonstrates that the boundary control method is workable in the case of complicated and irregular field of acoustic rays. By the use of the chosen boundary controls, an `averaged' profile of the sound speed is recovered (the relative error is about $10-15\\%$). Such a profile can be further utilized as a starting approximation for high resolution iterative reconstruction methods.

  4. A high precision instrument to measure angular and binocular deviation introduced by aircraft windscreens by using a shadow casting technique

    Energy Technology Data Exchange (ETDEWEB)

    Shivananju, B. N.; Yamdagni, S. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Vasu, R. M. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Applied Photonics Initiative, Indian Institute of Science, Bangalore 560012 (India); Asokan, S. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Applied Photonics Initiative, Indian Institute of Science, Bangalore 560012 (India); Robert Bosch Centre for Cyber Physical Systems, Indian Institute of Science, Bangalore 560012 (India)

    2012-12-15

    Objects viewed through transparent sheets with residual non-parallelism and irregularity appear shifted and distorted. This distortion is measured in terms of angular and binocular deviation of an object viewed through the transparent sheet. The angular and binocular deviations introduced are particularly important in the context of aircraft windscreens and canopies as they can interfere with decision making of pilots especially while landing, leading to accidents. In this work, we have developed an instrument to measure both the angular and binocular deviations introduced by transparent sheets. This instrument is especially useful in the qualification of aircraft windscreens and canopies. It measures the deviation in the geometrical shadow cast by a periodic dot pattern trans-illuminated by the distorted light beam from the transparent test specimen compared to the reference pattern. Accurate quantification of the shift in the pattern is obtained by cross-correlating the reference shadow pattern with the specimen shadow pattern and measuring the location of the correlation peak. The developed instrument is handy to use and computes both angular and binocular deviation with an accuracy of less than {+-}0.1 mrad ( Almost-Equal-To 0.036 mrad) and has an excellent repeatability with an error of less than 2%.

  5. Variability in the Speed of the Brewer-Dobson Circulation as Observed by Aura/MLS

    Science.gov (United States)

    Flury, Thomas; Wu, Dong L.; Read, W. G.

    2013-01-01

    We use Aura/MLS stratospheric water vapour (H2O) measurements as tracer for dynamics and infer interannual variations in the speed of the Brewer-Dobson circulation (BDC) from 2004 to 2011. We correlate one-year time series of H2O in the lower stratosphere at two subsequent pressure levels (68 hPa, approx.18.8 km and 56 hPa, approx 19.9 km at the Equator) and determine the time lag for best correlation. The same calculation is made on the horizontal on the 100 hPa (approx 16.6 km) level by correlating the H2O time series at the Equator with the ones at 40 N and 40 S. From these lag coefficients we derive the vertical and horizontal speeds of the BDC in the tropics and extra-tropics, respectively. We observe a clear interannual variability of the vertical and horizontal branch. The variability reflects signatures of the Quasi Biennial Oscillation (QBO). Our measurements confirm the QBO meridional circulation anomalies and show that the speed variations in the two branches of the BDC are out of phase and fairly well anti-correlated. Maximum ascent rates are found during the QBO easterly phase. We also find that transport of H2O towards the Northern Hemisphere (NH) is on the average two times faster than to the Southern Hemisphere (SH) with a mean speed of 1.15m/s at 100 hPa. Furthermore, the speed towards the NH shows much more interannual variability with an amplitude of about 21% whilst the speed towards the SH varies by only 10 %. An amplitude of 21% is also observed in the variability of the ascent rate at the Equator which is on the average 0.2mm/s.

  6. Aircraft Configuration and Flight Crew Compliance with Procedures While Conducting Flight Deck Based Interval Management (FIM) Operations

    Science.gov (United States)

    Shay, Rick; Swieringa, Kurt A.; Baxley, Brian T.

    2012-01-01

    Flight deck based Interval Management (FIM) applications using ADS-B are being developed to improve both the safety and capacity of the National Airspace System (NAS). FIM is expected to improve the safety and efficiency of the NAS by giving pilots the technology and procedures to precisely achieve an interval behind the preceding aircraft by a specific point. Concurrently but independently, Optimized Profile Descents (OPD) are being developed to help reduce fuel consumption and noise, however, the range of speeds available when flying an OPD results in a decrease in the delivery precision of aircraft to the runway. This requires the addition of a spacing buffer between aircraft, reducing system throughput. FIM addresses this problem by providing pilots with speed guidance to achieve a precise interval behind another aircraft, even while flying optimized descents. The Interval Management with Spacing to Parallel Dependent Runways (IMSPiDR) human-in-the-loop experiment employed 24 commercial pilots to explore the use of FIM equipment to conduct spacing operations behind two aircraft arriving to parallel runways, while flying an OPD during high-density operations. This paper describes the impact of variations in pilot operations; in particular configuring the aircraft, their compliance with FIM operating procedures, and their response to changes of the FIM speed. An example of the displayed FIM speeds used incorrectly by a pilot is also discussed. Finally, this paper examines the relationship between achieving airline operational goals for individual aircraft and the need for ATC to deliver aircraft to the runway with greater precision. The results show that aircraft can fly an OPD and conduct FIM operations to dependent parallel runways, enabling operational goals to be achieved efficiently while maintaining system throughput.

  7. Lightning hazards to aircraft

    Science.gov (United States)

    Corn, P. B.

    1978-01-01

    Lightning hazards and, more generally, aircraft static electricity are discussed by a representative for the Air Force Flight Dynamics Laboratory. An overview of these atmospheric electricity hazards to aircraft and their systems is presented with emphasis on electrical and electronic subsystems. The discussion includes reviewing some of the characteristics of lightning and static electrification, trends in weather and lightning-related mishaps, some specific threat mechanisms and susceptible aircraft subsystems and some of the present technology gaps. A roadmap (flow chart) is presented to show the direction needed to address these problems.

  8. 32 CFR 705.5 - Taking of photos on board naval ships, aircraft and installations by members of the general public.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 5 2010-07-01 2010-07-01 false Taking of photos on board naval ships, aircraft... Defense (Continued) DEPARTMENT OF THE NAVY UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS PUBLIC AFFAIRS REGULATIONS § 705.5 Taking of photos on board naval ships, aircraft and installations by...

  9. 31 CFR 515.558 - Bunkering of Cuban vessels and fueling of Cuban aircraft by American-owned or controlled foreign...

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Bunkering of Cuban vessels and... Licensing Policy § 515.558 Bunkering of Cuban vessels and fueling of Cuban aircraft by American-owned or... in transactions ordinarily incident to the bunkering of vessels and to the fueling of aircraft...

  10. 3D organization of high-speed compressible jets by tomographic PIV

    NARCIS (Netherlands)

    Violato, D.; Ceglia, G.; Tuinstra, M.; Scarano, F.

    2013-01-01

    This work investigates the three dimensional organization of compressible jets at high-speed regime by tomographic particle image velocimetry (TOMO PIV). Experiments are conducted at Mach numbers 0.3, 0.9 and 1.1 (underexpanded regime) across the end of the potential core within a large cylindrica

  11. Input current interharmonics in adjustable speed drives caused by fixed-frequency modulation techniques

    DEFF Research Database (Denmark)

    Soltani, Hamid; Davari, Pooya; Loh, Poh Chiang;

    2016-01-01

    Adjustable Speed Drives (ASDs) based on double-stage conversion systems may inject interharmonics distortion into the grid, other than the well-known characteristic harmonic components. The problems created by interharmonics make it necessary to find their precise sources, and, to adopt an approp...

  12. Genetic Analysis of Daily Maximum Milking Speed by a Random Walk Model in Dairy Cows

    DEFF Research Database (Denmark)

    Karacaören, Burak; Janss, Luc; Kadarmideen, Haja

    Data were obtained from dairy cows stationed at research farm ETH Zurich for maximum milking speed. The main aims of this paper are a) to evaluate if the Wood curve is suitable to model mean lactation curve b) to predict longitudinal breeding values by random regression and random walk models...

  13. Solar thermal aircraft

    Science.gov (United States)

    Bennett, Charles L.

    2007-09-18

    A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  14. The stable isotopic composition of molecular hydrogen in the tropopause region probed by the CARIBIC aircraft

    Directory of Open Access Journals (Sweden)

    A. M. Batenburg

    2012-05-01

    Full Text Available More than 450 air samples that were collected in the upper troposphere – lower stratosphere (UTLS region by the CARIBIC aircraft (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container have been analyzed for molecular hydrogen (H2 mixing ratios (χ(H2 and H2 isotopic composition (deuterium content, δD.

    More than 120 of the analyzed samples contained air from the lowermost stratosphere (LMS. These show that χ(H2 does not vary appreciably with O3-derived height above the thermal tropopause (TP, whereas δD does increase with height. The isotope enrichment is caused by H2 production and destruction processes that enrich the stratospheric H2 reservoir in deuterium (D; the exact shapes of the profiles are mainly determined by mixing of stratospheric with tropospheric air. Tight negative correlations are found between δD and the mixing ratios of methane (χ(CH4 and nitrous oxide (χ(N2O, as a result of the relatively long lifetimes of these three species. The correlations are described by δD[‰]=−0.35 · χ(CH4[ppb]+768 and δD[‰]=−1.90· χ(N2O[ppb]+745. These correlations are similar to previously published results and likely hold globally for the LMS.

    Samples that were collected from the Indian subcontinent up to 40° N before, during and after the summer monsoon season show no significant seasonal change in χ(H2, but δD is up to 12.3‰ lower in the July, August and September monsoon samples. This δD decrease is correlated with the χ(CH4 increase in these samples. The significant correlation with χ(CH4 and the absence of a perceptible χ(H2 increase that accompanies the δD decrease indicates that microbial production of

  15. Fine micro-welding of thin metal sheet by high speed laser scanning

    Science.gov (United States)

    Okamoto, Yasuhiro; Gillner, Arnold; Olowinsky, Alexander; Gedicke, Jens; Uno, Yoshiyuki

    2007-05-01

    Recently, since the size of component becomes smaller, then the welding of thin metal sheet has been required. Besides, the flexibility of process is important according to the accessibility especially for small components. Fraunhofer Institute for Laser Technology had developed the SHADOW ® welding technology, in which the high speed joining with small distortion is possible using pulsed Nd:YAG laser. The possibility of high speed and high quality welding had been reported by using single-mode fiber laser. The combination of micro beam and high speed laser scanning has the advantages for thin metal sheet welding. Therefore, the characteristics of micro-welding for thin metal sheet were investigated by high speed laser scanning, in which the welding was carried out by high speed scanner system with single-mode fiber laser and pulsed Nd:YAG laser. The proper welding region was narrow by the laser beam with a large focus diameter of 160 μm without pulse control, while a small focus diameter of 22 μm can control the welding state widely. A small focus diameter can perform the excellent welding seam from the extreme beginning without pulse control. The penetration depth can be controlled by the energy density with a small focus diameter of 22 μm at the energy densities less than 1 J/mm2. Besides, the unique periodic structure appeared at the high velocity of beam scanning with a small focus diameter. Moreover, the overlap welding of 25 μm thickness sheet can be performed regardless of small gap distance between two sheets by the laser beam with a small focus diameter of 22 μm.

  16. Short-Term Wind Speed Forecasting Using Support Vector Regression Optimized by Cuckoo Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Jianzhou Wang

    2015-01-01

    Full Text Available This paper develops an effectively intelligent model to forecast short-term wind speed series. A hybrid forecasting technique is proposed based on recurrence plot (RP and optimized support vector regression (SVR. Wind caused by the interaction of meteorological systems makes itself extremely unsteady and difficult to forecast. To understand the wind system, the wind speed series is analyzed using RP. Then, the SVR model is employed to forecast wind speed, in which the input variables are selected by RP, and two crucial parameters, including the penalties factor and gamma of the kernel function RBF, are optimized by various optimization algorithms. Those optimized algorithms are genetic algorithm (GA, particle swarm optimization algorithm (PSO, and cuckoo optimization algorithm (COA. Finally, the optimized SVR models, including COA-SVR, PSO-SVR, and GA-SVR, are evaluated based on some criteria and a hypothesis test. The experimental results show that (1 analysis of RP reveals that wind speed has short-term predictability on a short-term time scale, (2 the performance of the COA-SVR model is superior to that of the PSO-SVR and GA-SVR methods, especially for the jumping samplings, and (3 the COA-SVR method is statistically robust in multi-step-ahead prediction and can be applied to practical wind farm applications.

  17. Biodegradation of international jet A-1 aviation fuel by microorganisms isolated from aircraft tank and joint hydrant storage systems.

    Science.gov (United States)

    Itah, A Y; Brooks, A A; Ogar, B O; Okure, A B

    2009-09-01

    Microorganisms contaminating international Jet A-1 aircraft fuel and fuel preserved in Joint Hydrant Storage Tank (JHST) were isolated, characterized and identified. The isolates were Bacillus subtillis, Bacillus megaterium, Flavobacterium oderatum, Sarcina flava, Micrococcus varians, Pseudomonas aeruginosa, Bacillus licheniformis, Bacillus cereus and Bacillus brevis. Others included Candida tropicalis, Candida albicans, Saccharomyces estuari, Saccharomyces cerevisiae, Schizosaccharomyces pombe, Aspergillus flavus, Aspergillus niger, Aspergillus fumigatus, Cladosporium resinae, Penicillium citrinum and Penicillium frequentans. The viable plate count of microorganisms in the Aircraft Tank ranged from 1.3 (+/-0.01) x 104 cfu/mL to 2.2 (+/-1.6) x 104 cfu/mL for bacteria and 102 cfu/mL to 1.68 (+/-0.32) x 103 cfu/mL for fungi. Total bacterial counts of 1.79 (+/-0.2) x 104 cfu/mL to 2.58 (+/-0.04) x 104 cfu/mL and total fungal count of 2.1 (+/-0.1) x 103 cfu/mL to 2.28 (+/-0.5) x 103 cfu/mL were obtained for JHST. Selected isolates were re-inoculated into filter sterilized aircraft fuels and biodegradation studies carried out. After 14 days incubation, Cladosporium resinae exhibited the highest degradation rate with a percentage weight loss of 66 followed by Candida albicans (60.6) while Penicillium citrinum was the least degrader with a weight loss of 41.6%. The ability of the isolates to utilize the fuel as their sole source of carbon and energy was examined and found to vary in growth profile between the isolates. The results imply that aviation fuel could be biodegraded by hydrocarbonoclastic microorganisms. To avert a possible deterioration of fuel quality during storage, fuel pipe clogging and failure, engine component damage, wing tank corrosion and aircraft disaster, efficient routine monitoring of aircraft fuel systems is advocated.

  18. Aircraft systems design methodology and dispatch reliability prediction

    OpenAIRE

    Bineid, Mansour

    2005-01-01

    Aircraft despatch reliability was the main subject of this research in the wider content of aircraft reliability. The factors effecting dispatch reliability, aircraft delay, causes of aircraft delays, and aircraft delay costs and magnitudes were examined. Delay cost elements and aircraft delay scenarios were also studied. It concluded that aircraft dispatch reliability is affected by technical and non-technical factors, and that the former are under the designer's control. It showed that ...

  19. Amphibious Aircraft

    Data.gov (United States)

    National Aeronautics and Space Administration — A brief self composed research article on Amphibious Aircrafts discussing their use, origin and modern day applications along with their advantages and disadvantages...

  20. On the experimental prediction of the stability threshold speed caused by rotating damping

    Science.gov (United States)

    Vervisch, B.; Derammelaere, S.; Stockman, K.; De Baets, P.; Loccufier, M.

    2016-08-01

    An ever increasing demand for lighter rotating machinery and higher operating speeds results in a raised probability of instabilities. Rotating damping is one of the reasons, instability occurs. Rotating damping, or rotor internal damping, is the damping related to all rotating parts while non-rotating damping appearing in the non-rotating parts. The present study describes a rotating setup, designed to investigate rotating damping experimentally. An efficient experimental procedure is presented to predict the stability threshold of a rotating machine. The setup consists of a long thin shaft with a disk in the middle and clamped boundary conditions. The goal is to extract the system poles as a function of the rotating speed. The real parts of these poles are used to construct the decay rate plot, which is an indication for the stability. The efficiency of the experimental procedure relies on the model chosen for the rotating shaft. It is shown that the shaft behavior can be approximated by a single degree of freedom model that incorporates a speed dependent damping. As such low measurement effort and only one randomly chosen measurement location are needed to construct the decay rate plot. As an excitation, an automated impact hammer is used and the response is measured by eddy current probes. The proposed method yields a reliable prediction of the stability threshold speed which is validated through measurements.

  1. Near surface spatially averaged air temperature and wind speed determined by acoustic travel time tomography

    Directory of Open Access Journals (Sweden)

    Armin Raabe

    2001-03-01

    Full Text Available Acoustic travel time tomography is presented as a possibility for remote monitoring of near surface airtemperature and wind fields. This technique provides line-averaged effective sound speeds changing with temporally and spatially variable air temperature and wind vector. The effective sound speed is derived from the travel times of sound signals which propagate at defined paths between different acoustic sources and receivers. Starting with the travel time data a tomographic algorithm (Simultaneous Iterative Reconstruction Technique, SIRT is used to calculate area-averaged air temperature and wind speed. The accuracy of the experimental method and the tomographic inversion algorithm is exemplarily demonstrated for one day without remarkable differences in the horizontal temperature field, determined by independent in situ measurements at different points within the measuring field. The differences between the conventionally determined air temperature (point measurement and the air temperature determined by tomography (area-averaged measurement representative for the area of the measuring field 200m x 260m were below 0.5 K for an average of 10 minutes. The differences obtained between the wind speed measured at a meteorological mast and calculated from acoustic measurements are not higher than 0.5 ms-1 for the same averaging time. The tomographically determined area-averaged distribution of air temperature (resolution 50 m x 50 m can be used to estimate the horizontal gradient of air temperature as a pre-condition to detect horizontal turbulent fluxes of sensible heat.

  2. Enhanced Response Speed of ZnO Nanowire Photodetector by Coating with Photoresist

    Directory of Open Access Journals (Sweden)

    Xing Yang

    2016-01-01

    Full Text Available Spin-coating photoresist film on ZnO nanowire (NW was introduced into the fabrication procedure to improve photoresponse and recovery speed of a ZnO NW ultraviolet photoelectric detector. A ZnO NW was first assembled on prefabricated electrodes by dielectrophoresis. Then, photoresist was spin-coated on the nanowire. Finally, a metal layer was electrodeposited on the nanowire-electrode contacts. The response properties and I-V characteristics of ZnO NW photodetector were investigated by measuring the electrical current under different conditions. Measurement results demonstrated that the detector has an enhanced photoresponse and recovery speed after coating the nanowire with photoresist. The photoresponse and recovery characteristics of detectors with and without spin-coating were compared to demonstrate the effects of photoresist and the enhancement of response and recovery speed of the photodetector is ascribed to the reduced surface absorbed oxygen molecules and binding effect on the residual oxygen molecules after photoresist spin-coating. The results demonstrated that surface coating may be an effective and simple way to improve the response speed of the photoelectric device.

  3. Optimal Combination of Aircraft Maintenance Tasks by a Novel Simplex Optimization Method

    Directory of Open Access Journals (Sweden)

    Huaiyuan Li

    2015-01-01

    Full Text Available Combining maintenance tasks into work packages is not only necessary for arranging maintenance activities, but also critical for the reduction of maintenance cost. In order to optimize the combination of maintenance tasks by fuzzy C-means clustering algorithm, an improved fuzzy C-means clustering model is introduced in this paper. In order to reduce the dimension, variables representing clustering centers are eliminated in the improved cluster model. So the improved clustering model can be directly solved by the optimization method. To optimize the clustering model, a novel nonlinear simplex optimization method is also proposed in this paper. The novel method searches along all rays emitting from the center to each vertex, and those search directions are rightly n+1 positive basis. The algorithm has both theoretical convergence and good experimental effect. Taking the optimal combination of some maintenance tasks of a certain aircraft as an instance, the novel simplex optimization method and the clustering model both exhibit excellent performance.

  4. Tropical Cyclone Precipitation Types and Electrical Field Information Observed by High Altitude Aircraft Instrumentation

    Science.gov (United States)

    Hood, Robbie E.; Blakeslee, Richard; Cecil, Daniel; LaFontaine, Frank J.; Heymsfield, Gerald; Marks, Frank

    2004-01-01

    During the 1998 and 200 1 hurricane seasons of the Atlantic Ocean Basin, the Advanced Microwave Precipitation Radiometer (AMPR), the ER-2 Doppler (EDOP) radar, and the Lightning Instrument Package (LIP) were flown aboard the National Aeronautics and Space Administration (NASA) ER-2 high altitude aircraft as part of the Third Convection And Moisture Experiment (CAMEX-3) and the Fourth Convection And Moisture Experiment (CAMEX-4). Several hurricanes and tropical storms were sampled during these experiments. A rainfall screening technique has been developed using AMPR passive microwave observations of these tropical cyclones (TC) collected at frequencies of 10.7, 19.35,37.1, and 85.5 GHz and verified using vertical profiles of EDOP reflectivity and lower altitude horizontal reflectivity scam collected by the National Oceanic and Atmospheric Administration (NOM) P-3 radar. Matching the rainfall classification results with coincident electrical field information collected by the LIP readily identifl convective rain regions within the TC precipitation fields. Strengths and weaknesses of the rainfall classification procedure will be discussed as well as its potential as a real-time analysis tool for monitoring vertical updrafl strength and convective intensity from a remotely operated or uninhabited aerial vehicle.

  5. Solidification microstructure of M2 high speed steel by different casting technologies

    OpenAIRE

    Zhou Xuefeng; Fang Feng; Jiang Jianjing

    2011-01-01

    The present work investigated the solidification microstructure of AISI M2 high speed steel manufactured by different casting technologies, namely iron mould casting and continuous casting. The results revealed that the as-cast structure of the steel was composed of the iron matrix and the M2C eutectic carbide networks, which were greatly refined in the ingot made by continuous casting process, compared with that by the iron mould casting process. M2C eutectic carbides presented variation in ...

  6. Essentials of aircraft armaments

    CERN Document Server

    Kaushik, Mrinal

    2017-01-01

    This book aims to provide a complete exposure about armaments from their design to launch from the combat aircraft. The book details modern ammunition and their tactical roles in warfare. The proposed book discusses aerodynamics, propulsion, structural as well as navigation, control, and guidance of aircraft armament. It also introduces the various types of ammunition developed by different countries and their changing trends. The book imparts knowledge in the field of design, and development of aircraft armaments to aerospace engineers and covers the role of the United Nations in peacekeeping and disarmament. The book will be very useful to researchers, students, and professionals working in design and manufacturing of aircraft armaments. The book will also serve air force and naval aspirants, and those interested in working on defence research and developments organizations. .

  7. Annoyance caused by advanced turboprop aircraft flyover noise: Comparison of different propeller configurations

    Science.gov (United States)

    Mccurdy, David A.

    1991-01-01

    A laboratory experiment was conducted to compare the annoyance of flyover noise from advanced turboprop aircraft having different propeller configurations with the annoyance of conventional turboprop and turbofan aircraft flyover noise. A computer synthesis system was used to generate 40 realistic, time varying simulations of advanced turboprop takeoff noise. Of the 40 noises, single-rotating propeller configurations (8) and counter-rotating propeller configurations with an equal (12) and unequal (20) number of blades on each rotor were represented. Analyses found that advanced turboprops with single-rotating propellers were, on average, slightly less annoying than the other aircraft. Fundamental frequency and tone-to-broadband noise ratio affected annoyance response to advanced turboprops, but the effects varied with propeller configuration and noise metric. The addition of duration corrections and corrections for tones above 500 Hz to the noise measurement procedures improved annoyance prediction ability.

  8. Measurement of Aircraft Speed and Altitude

    Science.gov (United States)

    1980-05-01

    Albert W. Hall, Thomas M. Moul, Virgil S. Ritchie, and Robert T. Taylor who, as members of a technical review covinittee, made many valuable...Terry J.; and Webb, Lainie D.: Calibrations and Comparisons of Pressuie-Type Airspeed-Altitude Systems of the X-15 Airplane From Subsonic to High

  9. Direct Measurement of Light Speed Reduction in a Rubidium Vapour Medium Coherently Prepared by Electromagnetically Induced Transparency

    Institute of Scientific and Technical Information of China (English)

    涂鲜花; 王谨; 江开军; 何明; 李可; 仲嘉琪; 詹明生

    2003-01-01

    We have experimentally observed the reduction of light speed in a rubidium vapour medium coherently prepared by electromagnetically induced transparency.The light speed reduction was deduced by directly measuring the time delay of a probe light when it passed through the medium.The time delay varies with the intensity of the coupling laser,and the typical time delay we recorded was 1.8 μs,corresponding to a light speed of 56000m/s.

  10. RESEARCH OF NIGHT LIGHT EFFECTS ON COLORIMETRIC CHARACTERISTICS OF IMAGE PERCEIVED BY THE PILOT IN AN AIRCRAFT COCKPIT

    OpenAIRE

    I. O. Zharinov; O. O. Zharinov

    2015-01-01

    Subject of Research. The influence of radiation spectra from the source of artificial night light on colorimetric characteristics of image perceived by the pilot in the aircraft cockpit has been studied. The image is displayed on the LCD screen of multifunctional color indication equipment unit. Night illumination of the cockpit is performed with the use of artificial lamps of red, green, blue and, rarely, white light. Method. Any given color to be displayed on the screen is perceived by an o...

  11. Unstable phenomena of low speed compressible natural convection with open boundaries by multi-GPU implementation

    Science.gov (United States)

    Wang, Wei-Hsiang; Fu, Wu-Shung; Tsubokura, Makoto

    2016-11-01

    Unstable phenomena of low speed compressible natural convection are investigated numerically. Geometry contains parallel square plates or single heated plate with open boundaries is taken into consideration. Numerical methods of the Roe scheme, preconditioning and dual time stepping matching the DP-LUR method are used for low speed compressible flow. The absorbing boundary condition and modified LODI method is adopted to solve open boundary problems. High performance parallel computation is achieved by multi-GPU implementation with CUDA platform. The effects of natural convection by isothermal plates facing upwards in air is then carried out by the methods mentioned above Unstable behaviors appeared upon certain Rayleigh number with characteristic length respect to the width of plates or height between plates.

  12. Dynamics and control of robotic aircraft with articulated wings

    Science.gov (United States)

    Paranjape, Aditya Avinash

    There is a considerable interest in developing robotic aircraft, inspired by birds, for a variety of missions covering reconnaissance and surveillance. Flapping wing aircraft concepts have been put forth in light of the efficiency of flapping flight at small scales. These aircraft are naturally equipped with the ability to rotate their wings about the root, a form of wing articulation. This thesis covers some problems concerning the performance, stability and control of robotic aircraft with articulated wings in gliding flight. Specifically, we are interested in aircraft without a vertical tail, which would then use wing articulation for longitudinal as well as lateral-directional control. Although the dynamics and control of articulated wing aircraft share several common features with conventional fixed wing aircraft, the presence of wing articulation presents several unique benefits as well as limitations from the perspective of performance and control. One of the objective of this thesis is to understand these features using a combination of theoretical and numerical tools. The aircraft concept envisioned in this thesis uses the wing dihedral angles for longitudinal and lateral-directional control. Aircraft with flexible articulated wings are also investigated. We derive a complete nonlinear model of the flight dynamics incorporating dynamic CG location and the changing moment of inertia. We show that symmetric dihedral configuration, along with a conventional horizontal tail, can be used to control flight speed and flight path angle independently of each other. This characteristic is very useful for initiating an efficient perching maneuver. It is shown that wing dihedral angles alone can effectively regulate sideslip during rapid turns and generate a wide range of equilibrium turn rates while maintaining a constant flight speed and regulating sideslip. We compute the turning performance limitations that arise due to the use of wing dihedral for yaw control

  13. Seat Capacity Selection for an Advanced Short-Haul Aircraft Design

    Science.gov (United States)

    Marien, Ty V.

    2016-01-01

    A study was performed to determine the target seat capacity for a proposed advanced short-haul aircraft concept projected to enter the fleet by 2030. This analysis projected the potential demand in the U.S. for a short-haul aircraft using a transportation theory approach, rather than selecting a target seat capacity based on recent industry trends or current market demand. A transportation systems model was used to create a point-to-point network of short-haul trips and then predict the number of annual origin-destination trips on this network. Aircraft of varying seat capacities were used to meet the demand on this network, assuming a single aircraft type for the entire short-haul fleet. For each aircraft size, the ticket revenue and operational costs were used to calculate a total market profitability metric for all feasible flights. The different aircraft sizes were compared, based on this market profitability metric and also the total number of annual round trips and markets served. Sensitivity studies were also performed to determine the effect of changing the aircraft cruise speed and maximum trip length. Using this analysis, the advanced short-haul aircraft design team was able to select a target seat capacity for their design.

  14. Optimization of cold rolling process parameters in order to increasing rolling speed limited by chatter vibrations.

    Science.gov (United States)

    Heidari, Ali; Forouzan, Mohammad R

    2013-01-01

    Chatter has been recognized as major restriction for the increase in productivity of cold rolling processes, limiting the rolling speed for thin steel strips. It is shown that chatter has close relation with rolling conditions. So the main aim of this paper is to attain the optimum set points of rolling to achieve maximum rolling speed, preventing chatter to occur. Two combination methods were used for optimization. First method is done in four steps: providing a simulation program for chatter analysis, preparing data from simulation program based on central composite design of experiment, developing a statistical model to relate system tendency to chatter and rolling parameters by response surface methodology, and finally optimizing the process by genetic algorithm. Second method has analogous stages. But central composite design of experiment is replaced by Taguchi method and response surface methodology is replaced by neural network method. Also a study on the influence of the rolling parameters on system stability has been carried out. By using these combination methods, new set points were determined and significant improvement achieved in rolling speed.

  15. Automatic aircraft recognition

    Science.gov (United States)

    Hmam, Hatem; Kim, Jijoong

    2002-08-01

    Automatic aircraft recognition is very complex because of clutter, shadows, clouds, self-occlusion and degraded imaging conditions. This paper presents an aircraft recognition system, which assumes from the start that the image is possibly degraded, and implements a number of strategies to overcome edge fragmentation and distortion. The current vision system employs a bottom up approach, where recognition begins by locating image primitives (e.g., lines and corners), which are then combined in an incremental fashion into larger sets of line groupings using knowledge about aircraft, as viewed from a generic viewpoint. Knowledge about aircraft is represented in the form of whole/part shape description and the connectedness property, and is embedded in production rules, which primarily aim at finding instances of the aircraft parts in the image and checking the connectedness property between the parts. Once a match is found, a confidence score is assigned and as evidence in support of an aircraft interpretation is accumulated, the score is increased proportionally. Finally a selection of the resulting image interpretations with the highest scores, is subjected to competition tests, and only non-ambiguous interpretations are allowed to survive. Experimental results demonstrating the effectiveness of the current recognition system are given.

  16. Short-Term Wind Speed Forecast Based on B-Spline Neural Network Optimized by PSO

    Directory of Open Access Journals (Sweden)

    Zhongqiang Wu

    2015-01-01

    Full Text Available Considering the randomness and volatility of wind, a method based on B-spline neural network optimized by particle swarm optimization is proposed to predict the short-term wind speed. The B-spline neural network can change the division of input space and the definition of basis function flexibly. For any input, only a few outputs of hidden layers are nonzero, the outputs are simple, and the convergence speed is fast, but it is easy to fall into local minimum. The traditional method to divide the input space is thoughtless and it will influence the final prediction accuracy. Particle swarm optimization is adopted to solve the problem by optimizing the nodes. Simulated results show that it has higher prediction accuracy than traditional B-spline neural network and BP neural network.

  17. Impact of the vibrations on the environment caused by passages of trains at variable speed

    Directory of Open Access Journals (Sweden)

    Kożuch Barbara

    2016-01-01

    Full Text Available The paper deals with negative environmental impact caused by the passages of different kinds of trains at variable speed. The study is based on the measurement results which took place in Poland in 2013 on the railway line no. 4. The effect of the traction unit – Pendolino (EMU 250 on the vibration climate was analysed. The impact of passages of new trains was compared to currently operated rolling stock. The speed of trains was varying between 40 and 250 km/h. Vibration measurements were conducted by stuff of an accredited Laboratory of Structural Mechanics at Cracow University of Technology (Accreditation No. AB 826. The influence of the indicated vibrations due to passages of the trains on the building in the neighbourhood of the line was investigated. The vibration assessment was done for horizontal components of vibrations according to Polish standard code. Assessment of environmental impact was presented by indicator of perceptibility of vibration through construction (WODB, which refers to the Scales of Dynamic Influences (SDI scales. The limits specified by standards in any of the passages have not been exceeded. The change of speed or rolling stock resulted in a change in the characteristic of the vibration spectrum.

  18. Carbon balance of China constrained by CONTRAIL aircraft CO2 measurements

    Directory of Open Access Journals (Sweden)

    F. Jiang

    2014-03-01

    Full Text Available Terrestrial CO2 flux estimates in China using atmospheric inversion method are beset with considerable uncertainties because very few atmospheric CO2 concentration measurements are available. In order to improve these estimates, nested atmospheric CO2 inversion during 2002–2008 is performed in this study using passenger aircraft-based CO2 measurements over Eurasia from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL project. The inversion system includes 43 regions with a focus on China, and is based on the Bayesian synthesis approach and the TM5 transport model. The terrestrial ecosystem carbon flux modeled by the BEPS model and the ocean exchange simulated by the OPA-PISCES-T model are considered as the prior fluxes. The impacts of CONTRAIL CO2 data on inverted China terrestrial carbon fluxes are quantified, the improvement of the inverted fluxes after adding CONTRAIL CO2 data are rationed against climate factors and evaluated by comparing the simulated atmospheric CO2 concentrations with three independent surface CO2 measurements in China. Results show that with the addition of CONTRAIL CO2 data, the inverted carbon sink in China increases while those in South and Southeast Asia decrease. Meanwhile, the posterior uncertainties over these regions are all reduced. CONTRAIL CO2 data also have a large effect on the inter-annual variation of carbon sinks in China, leading to a better correlation between the carbon sink and the annual mean climate factors. Evaluations against the CO2 measurements at three sites in China also show that the CONTRAIL CO2 measurements have improved the inversion results.

  19. Carbon balance of China constrained by CONTRAIL aircraft CO2 measurements

    Science.gov (United States)

    Jiang, F.; Wang, H. M.; Chen, J. M.; Machida, T.; Zhou, L. X.; Ju, W. M.; Matsueda, H.; Sawa, Y.

    2014-09-01

    Terrestrial carbon dioxide (CO2) flux estimates in China using atmospheric inversion method are beset with considerable uncertainties because very few atmospheric CO2 concentration measurements are available. In order to improve these estimates, nested atmospheric CO2 inversion during 2002-2008 is performed in this study using passenger aircraft-based CO2 measurements over Eurasia from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. The inversion system includes 43 regions with a focus on China, and is based on the Bayesian synthesis approach and the TM5 transport model. The terrestrial ecosystem carbon flux modeled by the Boreal Ecosystems Productivity Simulator (BEPS) model and the ocean exchange simulated by the OPA-PISCES-T model are considered as the prior fluxes. The impacts of CONTRAIL CO2 data on inverted China terrestrial carbon fluxes are quantified, the improvement of the inverted fluxes after adding CONTRAIL CO2 data are rationed against climate factors and evaluated by comparing the simulated atmospheric CO2 concentrations with three independent surface CO2 measurements in China. Results show that with the addition of CONTRAIL CO2 data, the inverted carbon sink in China increases while those in South and Southeast Asia decrease. Meanwhile, the posterior uncertainties over these regions are all reduced (2-12%). CONTRAIL CO2 data also have a large effect on the inter-annual variation of carbon sinks in China, leading to a better correlation between the carbon sink and the annual mean climate factors. Evaluations against the CO2 measurements at three sites in China also show that the CONTRAIL CO2 measurements may have improved the inversion results.

  20. Investigation on the interference correction of flying wing aircraft rear sting support in high speed wind tunnel test%飞翼布局高速风洞尾支干扰试验修正技术研究

    Institute of Scientific and Technical Information of China (English)

    衣秉立; 曾凯; 王世红

    2016-01-01

    For the test of a flat-after-body flying wing aircraft model in high speed wind tun-nel,the after-body has to be modified to satisfied the attachment of the balance.The deformation and the means of tail support may have some effect on the aerodynamic characteristics of the air-craft,and further affect the cruising efficiency,the trimming angle and the location of the aero-dynamic center.On the other hand,there are no commonly used horizontal tail and vertical tail for a flying wing aircraft in order to reduce RCS,the interference of distorted after-body can not to be neglected compares to weak lateral controllability.With the help of CFD and test tech-nique,the distorted after-body support interference has been obtained,in which rear sting is the main support and ventral strut an auxiliary one.The research indicates that the result of the wind tunnel test is accurate and reliable,the correction method can be adopted for the similar configu-ration model test.The methods of both numerical simulation and wind tunnel tests have been used to correct tail support interference of a flying wing model successfully.%飞翼布局飞行器模型往往具有尾部扁平的结构特点,进行高速风洞尾支测力时,尾部需要局部放大,由此带来尾部畸变和尾支杆的气动干扰,直接影响对巡航效率、焦点位置以及配平迎角的预测;另外,飞翼布局飞机为改善隐身特性,取消了平尾和垂尾,侧力和偏航力矩量级比较小,模型尾部的局部变形必然会对飞机横、航向试验数据带来不利影响。本文针对某飞翼布局模型,采用风洞试验和 CFD 数值模拟相结合的手段,通过腹支撑作为辅助支撑的“两步法”获得了尾部畸变及尾支杆的纵、横向支撑干扰影响。研究结果表明:该飞翼布局模型尾部畸变支撑纵、横向支撑干扰修正结果合理、可靠,精准度较高;所建立的试验与 CFD 相结合的研究方法可以用于

  1. Use of Non-Wildlife Passages Across a High Speed Railway by Terrestrial Vertebrates

    OpenAIRE

    Rodríguez, Alejandro; Crema, Giulia; Delibes, M.

    1996-01-01

    Seventeen culverts and pathway passages across a high speed railway were monitored for one year in order to determine factors influencing their use by terrestrial vertebrates. 2. Carnivores, lagomorphs, small mammals and reptiles used the passages. Crossing rates generally reflected the spatiotemporal variation in vertebrate abundance and activity, suggesting that the passages could be valuable in allowing movement across the railway. 3. Wild ungulates known to be present did not use the pass...

  2. 76 FR 31465 - Airworthiness Directives; Various Aircraft Equipped With Rotax Aircraft Engines 912 A Series Engine

    Science.gov (United States)

    2011-06-01

    ... Aircraft Equipped With Rotax Aircraft Engines 912 A Series Engine AGENCY: Federal Aviation Administration...://www.rotax-aircraft-engines.com . You may review copies of the referenced service information at the... by examining the MCAI in the AD docket. Relevant Service Information Rotax Aircraft Engines...

  3. Linear regulator design for stochastic systems by a multiple time scales method. [with application to F-8 aircraft longitudinal control

    Science.gov (United States)

    Teneketzis, D.; Sandell, N. R., Jr.

    1976-01-01

    This paper develops a hierarchically-structured, suboptimal controller for a linear stochastic system composed of fast and slow subsystems. It is proved that the controller is optimal in the limit as the separation of time scales of the subsystems becomes infinite. The methodology is illustrated by design of a controller to suppress the phugoid and short period modes of the longitudinal dynamics of the F-8 aircraft.

  4. Isolation of deoxypodophyllotoxin and podophyllotoxin from Juniperus sabina by high speed counter current chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y.; Yang, Y.; Chen, Q.; Kasimu, R.; Aisa, H.A.

    2016-11-01

    Deoxypodophyllotoxin and podophyllotoxin are known for their excellent anti-proliferative and anti-tumor activities, therefore large amount of pure compounds is urgently needed as authentic standards for various in vivo and in vitro studies. In this paper, an effective, rapid separation and purification method of deoxypodophyllotoxin and podophyllotoxin from the crude extract of Juniperus sabina was established using high speed counter current chromatography (HSCCC). HSCCC was performed with atwo phase solvent system comprising of n-hexane-ethylacetate-methanol-water (3:5:3:5, v/v) at the flow rate of 2mL/min at the speed of 850 rpm. 34.8 mg of deoxypodophyllotoxin and 7.9 mg of podophyllotoxin were obtained from 200 mg crude sample with a purity of 96.5% and 94.4%, respectively, as determined by high performance liquid chromatography (HPLC). (Author)

  5. Variable speed wind turbine control by discrete-time sliding mode approach.

    Science.gov (United States)

    Torchani, Borhen; Sellami, Anis; Garcia, Germain

    2016-05-01

    The aim of this paper is to propose a new design variable speed wind turbine control by discrete-time sliding mode approach. This methodology is designed for linear saturated system. The saturation constraint is reported on inputs vector. To this end, the back stepping design procedure is followed to construct a suitable sliding manifold that guarantees the attainment of a stabilization control objective. It is well known that the mechanisms are investigated in term of the most proposed assumptions to deal with the damping, shaft stiffness and inertia effect of the gear. The objectives are to synthesize robust controllers that maximize the energy extracted from wind, while reducing mechanical loads and rotor speed tracking combined with an electromagnetic torque. Simulation results of the proposed scheme are presented.

  6. Effective visual short-term storage capacity and speed of encoding are affected by arousal

    DEFF Research Database (Denmark)

    Sørensen, Thomas Alrik; Bundesen, Claus

    2011-01-01

    Effects of spatial cueing on visual attention have been thoroughly investigated during the last 30 odd years. Similar to spatial cueing, temporal cueing seems to afford a performance enhancement to an observer when he or she knows the point in time at which an event will occur (Coull & Nobre, 1998......). Varying the statistical distribution of cue-stimulus onset asynchronies (foreperiods) is an effective way of manipulating the observer's temporal expectancies and, presumably, the observer's level of arousal. By use of this manipulation, Vangkilde and Bundesen (2009) found strong evidence that speed...... of encoding into visual short-term memory (VSTM) increased with the level of arousal in a single-stimulus identification experiment. Here we present a whole-report experiment corroborating the finding that speed of encoding stimulus items (letters) into VSTM increases with the level of arousal. However...

  7. A new diagnostic method for separating airborne and structureborne noise radiated by plates with applications for propeller driven aircraft

    Science.gov (United States)

    Mcgary, Michael C.

    1988-01-01

    The anticipated application of advanced turboprop propulsion systems is expected to increase the interior noise of future aircraft to unacceptably high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a prime obstacle in the development of efficient noise control treatments for propeller-driven aircraft. A new diagnostic method that permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on an aluminum plate. The results of the study indicate that the proposed method could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available.

  8. Speed of invasion of an expanding population by a horizontally transmitted trait.

    Science.gov (United States)

    Venegas-Ortiz, Juan; Allen, Rosalind J; Evans, Martin R

    2014-02-01

    Range expansions are a ubiquitous phenomenon, leading to the spatial spread of genetic, ecological, and cultural traits. While some of these traits are advantageous (and hence selected), other, nonselected traits can also spread by hitchhiking on the wave of population expansion. This requires us to understand how the spread of a hitchhiking trait is coupled to the wave of advance of its host population. Here, we use a system of coupled Fisher-Kolmogorov-Petrovsky-Piskunov (F-KPP) equations to describe the spread of a horizontally transmitted hitchhiking trait within a population as it expands. We extend F-KPP wave theory to the system of coupled equations to predict how the hitchhiking trait spreads as a wave within the expanding population. We show that the speed of this trait wave is controlled by an intricate coupling between the tip of the population and trait waves. Our analysis yields a new speed selection mechanism for coupled waves of advance and reveals the existence of previously unexpected speed transitions.

  9. Temperature change in pig rib bone during implant site preparation by low-speed drilling

    Directory of Open Access Journals (Sweden)

    Sun-Jong Kim

    2010-10-01

    Full Text Available OBJECTIVES: The purpose of this study was to evaluate the temperature change during low-speed drilling using infrared thermography. MATERIAL AND METHODS: Pig ribs were used to provide cortical bone of a similar quality to human mandible. Heat production by three implant drill systems (two conventional drilling systems and one low-speed drilling system was evaluated by measuring the bone temperature using infrared thermography. Each system had two different bur sizes. The drill systems used were twist drill (2.0 mm/2.5 mm, which establishes the direction of the implant, and finally a 3.0 mm-pilot drill. Thermal images were recorded using the IRI1001 system (Infrared Integrated Systems Ltd.. Baseline temperature was 31±1ºC. Measurements were repeated 10 times, and a static load of 10 kg was applied while drilling. Data were analyzed using descriptive statistics. Statistical analysis was conducted with two-way ANOVA. RESULTS AND CONCLUSIONS: Mean values (n=10 drill sequences for maximum recorded temperature (Max TºC, change in temperature (ΔTºC from baseline were as follows. The changes in temperature (ΔTºC were 1.57ºC and 2.46ºC for the lowest and the highest values, respectively. Drilling at 50 rpm without irrigation did not produce overheating. There was no significant difference in heat production between the 3 implant drill systems (p>0.05. No implant drill system produced heat exceeding 47ºC, which is the critical temperature for bone necrosis during low-speed drilling. Low-speed drilling without irrigation could be used during implant site preparation.

  10. A Rotating Speed Controller Design Method for Power Levelling by Means of Inertia Energy in Wind Power Systems

    DEFF Research Database (Denmark)

    Qin, Zian; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    Power fluctuation caused by wind speed variations may be harmful for the stability of the power system as well as the reliability of the wind power converter, since it may induce thermal excursions in the solder joints of the power modules. Using the wind turbine rotor inertia energy for power...... leveling has been studied before, but no quantified analysis or generic design method have been found. In this paper, the transfer functions from the wind speed to electrical power, electromagnetic torque, and rotating speed are built based on which the rotating speed controller is designed...

  11. Characterization of non-methane hydrocarbons in Asian summer monsoon outflow observed by the CARIBIC aircraft

    Directory of Open Access Journals (Sweden)

    A. K. Baker

    2010-07-01

    Full Text Available Between April and December 2008 the CARIBIC commercial aircraft conducted monthly measurement flights between Frankfurt, Germany and Chennai, India. These flights covered the period of the Asian summer monsoon (June–September, during which enhancements in a number of atmospheric species were observed in monsoon outflow. In addition to in situ measurements of trace gases and aerosols, whole air samples were collected during the flights, and these were subsequently analyzed for a suite of trace gases that included the non-methane hydrocarbons. Non-methane hydrocarbons are relatively short-lived compounds and the large enhancements in their mixing ratios in the upper troposphere over Southwest Asia between June and September, sometimes more than double their spring and fall means, provides qualitative evidence for the influence of convectively uplifted boundary layer air. The particularly large enhancements of the combustion tracers benzene and ethyne, along with the similarity of their ratios to carbon monoxide and emission ratios from the burning of household biofuels, indicate a strong influence of biofuel burning to NMHC emissions in this region. Conversely, the ratios of ethane and propane to carbon monoxide, along with the ratio between i-butane and n-butane, indicate a significant source of these compounds from the use of LPG and natural gas, and comparison to previous campaigns suggests that this source could be increasing. Photochemical aging patterns of NMHCs showed that the CARIBIC samples were collected in two distinctly different regions of the monsoon circulation: a southern region where air masses had been recently influenced by low level contact and a northern region, where air parcels had spent substantial time in transit in the upper troposphere before being probed. Estimates of age using ratios of individual NMHCs have ranges of 3–6 d in the south and 9–12 d in the north.

  12. A statistical study of underestimates of wind speeds by VHF radar

    Directory of Open Access Journals (Sweden)

    L. Thomas

    Full Text Available Comparisons are made between horizontal wind measurements carried out using a VHF-radar system at Aberystwyth (52.4°N, 4.1°W and radiosondes launched from Aberporth, some 50 km to the south-west. The radar wind results are derived from Doppler wind measurements at zenith angles of 6° in two orthogonal planes and in the vertical direction. Measurements on a total of 398 days over a 2-year period are considered, but the major part of the study involves a statistical analysis of data collected during 75 radiosonde flights selected to minimise the spatial separation of the two sets of measurements. Whereas good agreement is found between the two sets of wind direction, radar-derived wind speeds show underestimates of 4–6% compared with radiosonde values over the height range 4–14 km. Studies of the characteristics of this discrepancy in wind speeds have concentrated on its directional dependence, the effects of the spatial separation of the two sets of measurements, and the influence of any uncertainty in the radar measurements of vertical velocities. The aspect sensitivity of radar echoes has previously been suggested as a cause of underestimates of wind speeds by VHF radar. The present statistical treatment and case-studies show that an appropriate correction can be applied using estimates of the effective radar beam angle derived from a comparison of echo powers at zenith angles of 4.2° and 8.5°.

  13. Non-intrusive measurement of emission indices. A new approach to the evaluation of infrared spectra emitted by aircraft engine exhaust gases

    Energy Technology Data Exchange (ETDEWEB)

    Lindermeir, E.; Haschberger, P.; Tank, V. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Optoelektronik

    1997-12-31

    A non-intrusive method is used to determine the emission indices of a research aircraft`s engine in-flight. The principle is based on the Fourier Transform Infrared Spectrometer MIROR which was specifically designed and built for operation aboard aircrafts. This device measures the spectrum of the infrared radiation emitted by the hot exhaust gas under cruise conditions. From these spectra mixing ratios and emission indices can be derived. An extension to previously applied evaluation schemes is proposed: Whereas formerly the plume was assumed a homogeneous layer of gas, temperature and concentration profiles are now introduced to the evaluation procedure. (author) 5 refs.

  14. Phase Error Caused by Speed Mismatch Analysis in the Line-Scan Defect Detection by Using Fourier Transform Technique

    Directory of Open Access Journals (Sweden)

    Eryi Hu

    2015-01-01

    Full Text Available The phase error caused by the speed mismatch issue is researched in the line-scan images capturing 3D profile measurement. The experimental system is constructed by a line-scan CCD camera, an object moving device, a digital fringe pattern projector, and a personal computer. In the experiment procedure, the detected object is moving relative to the image capturing system by using a motorized translation stage in a stable velocity. The digital fringe pattern is projected onto the detected object, and then the deformed patterns are captured and recorded in the computer. The object surface profile can be calculated by the Fourier transform profilometry. However, the moving speed mismatch error will still exist in most of the engineering application occasion even after an image system calibration. When the moving speed of the detected object is faster than the expected value, the captured image will be compressed in the moving direction of the detected object. In order to overcome this kind of measurement error, an image recovering algorithm is proposed to reconstruct the original compressed image. Thus, the phase values can be extracted much more accurately by the reconstructed images. And then, the phase error distribution caused by the speed mismatch is analyzed by the simulation and experimental methods.

  15. Interaction of Aircraft Wakes From Laterally Spaced Aircraft

    Science.gov (United States)

    Proctor, Fred H.

    2009-01-01

    Large Eddy Simulations are used to examine wake interactions from aircraft on closely spaced parallel paths. Two sets of experiments are conducted, with the first set examining wake interactions out of ground effect (OGE) and the second set for in ground effect (IGE). The initial wake field for each aircraft represents a rolled-up wake vortex pair generated by a B-747. Parametric sets include wake interactions from aircraft pairs with lateral separations of 400, 500, 600, and 750 ft. The simulation of a wake from a single aircraft is used as baseline. The study shows that wake vortices from either a pair or a formation of B-747 s that fly with very close lateral spacing, last longer than those from an isolated B-747. For OGE, the inner vortices between the pair of aircraft, ascend, link and quickly dissipate, leaving the outer vortices to decay and descend slowly. For the IGE scenario, the inner vortices ascend and last longer, while the outer vortices decay from ground interaction at a rate similar to that expected from an isolated aircraft. Both OGE and IGE scenarios produce longer-lasting wakes for aircraft with separations less than 600 ft. The results are significant because concepts to increase airport capacity have been proposed that assume either aircraft formations and/or aircraft pairs landing on very closely spaced runways.

  16. LCC-OPS: Life Cycle Cost Application in Aircraft Operations

    NARCIS (Netherlands)

    Suwondo, E.

    2007-01-01

    Observation of current practices in aircraft operations and maintenance shows limited consideration of cost savings applied by aircraft modifications, maintenance program optimisation and aircraft selection. This is due to hidden (maintenance dependent) costs and difficulties in quantifying the util

  17. Scheduling of an aircraft fleet

    Science.gov (United States)

    Paltrinieri, Massimo; Momigliano, Alberto; Torquati, Franco

    1992-01-01

    Scheduling is the task of assigning resources to operations. When the resources are mobile vehicles, they describe routes through the served stations. To emphasize such aspect, this problem is usually referred to as the routing problem. In particular, if vehicles are aircraft and stations are airports, the problem is known as aircraft routing. This paper describes the solution to such a problem developed in OMAR (Operative Management of Aircraft Routing), a system implemented by Bull HN for Alitalia. In our approach, aircraft routing is viewed as a Constraint Satisfaction Problem. The solving strategy combines network consistency and tree search techniques.

  18. Aircraft cybernetics

    Science.gov (United States)

    1977-01-01

    The use of computers for aircraft control, flight simulation, and inertial navigation is explored. The man-machine relation problem in aviation is addressed. Simple and self-adapting autopilots are described and the assets and liabilities of digital navigation techniques are assessed.

  19. AIRTV: Broadband Direct to Aircraft

    Science.gov (United States)

    Sorbello, R.; Stone, R.; Bennett, S. B.; Bertenyi, E.

    2002-01-01

    Airlines have been continuously upgrading their wide-body, long-haul aircraft with IFE (in-flight entertainment) systems that can support from 12 to 24 channels of video entertainment as well as provide the infrastructure to enable in-seat delivery of email and internet services. This is a direct consequence of increased passenger demands for improved in-flight services along with the expectations that broadband delivery systems capable of providing live entertainment (news, sports, financial information, etc.) and high speed data delivery will soon be available. The recent events of Sept. 11 have slowed the airline's upgrade of their IFE systems, but have also highlighted the compelling need for broadband aeronautical delivery systems to include operational and safety information. Despite the impact of these events, it is estimated that by 2005 more than 3000 long haul aircraft (servicing approximately 1 billion passengers annually) will be fully equipped with modern IFE systems. Current aircraft data delivery systems, which use either Inmarsat or NATS, are lacking in bandwidth and consequently are unsuitable to satisfy passenger demands for broadband email/internet services or the airlines' burgeoning data requirements. Present live video delivery services are limited to regional coverage and are not readily expandable to global or multiregional service. Faced with a compelling market demand for high data transport to aircraft, AirTV has been developing a broadband delivery system that will meet both passengers' and airlines' needs. AirTV is a global content delivery system designed to provide a range of video programming and data services to commercial airlines. When AirTV is operational in 2004, it will provide a broadband connection directly to the aircraft, delivering live video entertainment, internet/email service and essential operational and safety data. The system has been designed to provide seamless global service to all airline routes except for those

  20. On the relationship of radar backscatter to wind speed and fetch. [ocean wave generation

    Science.gov (United States)

    Ross, D.; Jones, W. L.

    1978-01-01

    The physics of the interaction of electromagnetic waves with the ocean surface has been an active area of research for a number of years. This paper contains the results of satellite and aircraft experiments to investigate the ability of active microwave radars to infer surface wind speeds remotely. Data obtained from the recent National Aeronautics and Space Administration (NASA) Skylab experiment are compared with surface wind speeds measured by low-flying aircraft and ships-of-opportunity and found to give useful estimates of the ocean wind field. Also investigated was the influence of varying wave height on radar measurements of wind speed by measuring the backscattering cross-section for constant wind speed but variable wave conditions. It is found that this effect is of little importance.

  1. Modelling of the automatic stabilization system of the aircraft course by a fuzzy logic method

    Science.gov (United States)

    Mamonova, T.; Syryamkin, V.; Vasilyeva, T.

    2016-04-01

    The problem of the present paper concerns the development of a fuzzy model of the system of an aircraft course stabilization. In this work modelling of the aircraft course stabilization system with the application of fuzzy logic is specified. Thus the authors have used the data taken for an ordinary passenger plane. As a result of the study the stabilization system models were realised in the environment of Matlab package Simulink on the basis of the PID-regulator and fuzzy logic. The authors of the paper have shown that the use of the method of artificial intelligence allows reducing the time of regulation to 1, which is 50 times faster than the time when standard receptions of the management theory are used. This fact demonstrates a positive influence of the use of fuzzy regulation.

  2. Contamination and Distortion of Steady Flow Field Induced by Discrete Frequency in Aircraft Gas Turbines.

    Science.gov (United States)

    1984-05-16

    Ranque - Hilsch ( vortex tube ) effect." 5. List of Professional Personnel Associated with the Research The recipient of advanced degrees awarded in...SUB. GR. AIRCRAFT ENGINES RANQUE - HILSCH EFFECT i UNSTEADY FLOW ENERGY SEPARATION IN FLOW(KARMAN VORTEX STREET ORGAINIZED REYNOLDS STRESSES 19. ABSTRACT...turbomachinery. Specific objectives are twofold: Task (A). To complete the investigation of the Ranque - Hilsch effect con- ducted under AFOSR Contract

  3. Mitigation of Wind Power Fluctuation by Active Current Control of Variable Speed Wind Turbines

    DEFF Research Database (Denmark)

    Zhang, Yunqian; Chen, Zhe; Hu, Weihao;

    2013-01-01

    Wind shear and tower shadow are the sources of power fluctuation of grid connected wind turbines during continuous operation. This paper presents a simulation model of a MW-level doubly fed induction generator (DFIG) based variable speed wind turbine with a partial-scale back-to-back power...... converter in Simulink. A simple and effective method of wind power fluctuations mitigation by active current control of DFIG is proposed. It smoothes the generator output active power oscillations by adjusting the active current of the DFIG, such that the power oscillation is stored as the kinetic energy...

  4. Impedance seen by Distance Relays on Lines Fed from Fixed Speed Wind Turbines

    Science.gov (United States)

    Srivastava, Sachin; Shenoy, U. J.; Chandra Biswal, Abhinna; Sethuraman, Ganesan

    2013-05-01

    This paper deals with line protection challenges experienced in a system having substantial wind generation penetration. Two types of generators, thermal synchronous generators and fixed speed wind turbines based on squirrel-cage induction generators, are simulated as thevenin equivalent model, connected to grid with single-circuit transmission line. The paper gives comparative discussion and summarizes analytical investigations carried out on the impedance seen by distance relays by varying fault resistances and grid short circuit MVA, for the protection of such transmission lines during faults.

  5. Assessing Aircraft Timeliness Variations By Major Airlines: Passenger Travel Practice In Uganda

    Directory of Open Access Journals (Sweden)

    Ronald Wesonga

    2013-04-01

    Full Text Available Flight delays do not only affect passenger satisfaction but also carry along costly consequences to airlines. The overall objective of the study was to assess aircraft timeliness variations by major airlines so as to determine passenger travel practice in Uganda. The study hypotheses were tested using a two-way ANOVA F-test and further measures of associations. The study found out that the number of schedules of each airline per day had a positive effect on the delay duration, whereby an additional schedule increased the average delay by a proportion of 11%. Whereas the day of the week F(16, 1129 = 1.36, p >0.01 had no significant difference in the delays amongst the airlines, the month of the year F(33, 1107 = 1.88, p < 0.001 showed a significant difference. However, the total variance of the delays was attributed to the airline (29%. It was also demonstrated from the analysis that Eagle Air (EA, Kenya Airways (KA and South African Airways (SAA experienced more delays than the British Airways (BAW by 33%, 62% and 55% respectively. Other than Wednesday, flights were delayed more on all the days of the week and less delayed in the months of October and November than in June by 26% and 3% respectively. On Saturdays and Sundays, flights were found to have longer periods of delay (p<0.05 that averaged 14 and 13 minutes respectively. The flights in January and March had longer delays (15 and 14 minutes than that recorded in the other months. Therefore, it can be concluded that the passengers who use BAW are less likely to delay than the other (EA, KA and SAA airlines and travelling in the months of October and November is highly recommended. Given that airline delay is positively correlated with the number of scheduled flights, a policy framework could be developed to optimise schedules and airline delays during departure at the airport. The template is used to format your paper and style the text. All margins, column widths, line spaces, and text

  6. One-way-coupling simulation of cavitation accompanied by high-speed droplet impact

    Science.gov (United States)

    Kondo, Tomoki; Ando, Keita

    2016-03-01

    Erosion due to high-speed droplet impact is a crucial issue in industrial applications. The erosion is caused by the water-hammer loading on material surfaces and possibly by the reloading from collapsing cavitation bubbles that appear within the droplet. Here, we simulate the dynamics of cavitation bubbles accompanied by high-speed droplet impact against a deformable wall in order to see whether the bubble collapse is violent enough to give rise to cavitation erosion on the wall. The evolution of pressure waves in a single water (or gelatin) droplet to collide with a deformable wall at speed up to 110 m/s is inferred from simulations of multicomponent Euler flow where phase changes are not permitted. Then, we examine the dynamics of cavitation bubbles nucleated from micron/submicron-sized gas bubble nuclei that are supposed to exist inside the droplet. For simplicity, we perform Rayleigh-Plesset-type calculations in a one-way-coupling manner, namely, the bubble dynamics are determined according to the pressure variation obtained from the Euler flow simulation. In the simulation, the preexisting bubble nuclei whose size is either micron or submicron show large growth to submillimeters because tension inside the droplet is obtained through interaction of the pressure waves and the droplet interface; this supports the possibility of having cavitation due to the droplet impact. It is also found, in particular, for the case of cavitation arising from very small nuclei such as nanobubbles, that radiated pressure from the cavitation bubble collapse can overwhelm the water-hammer pressure directly created by the impact. Hence, cavitation may need to be accounted for when it comes to discussing erosion in the droplet impact problem.

  7. MISSILES AND AIRCRAFT (PART1

    Directory of Open Access Journals (Sweden)

    C.M. Meyer

    2012-02-01

    Full Text Available Many sources maintain that the role played by air power in the 1973 Yom Kippur War was important. Other interpretations state that control of air space over the battlefield areas, (either by aircraft or anti-aircraft defences, was vital.

  8. Instrumentation and data acquisition for full-scale aircraft crash testing

    Science.gov (United States)

    Jones, Lisa E.; Fasanella, Edwin L.

    1993-01-01

    The Landing and Impact Dynamics Branch of the NASA Langley Research Center has been conducting full-scale aircraft crash tests since the 1970s. Using a pendulum method, aircraft are suspended by cables from a 240-ft high gantry and swung into the impact surface at various attitudes and velocities. Instrumentation for these tests include on-board high-speed cameras, strain gages, load cells, displacement transducers, and accelerometers. Transducers in the aircraft are hard-wired through a long umbilical cable to the data acquisition room. Up to 96 channels of data can be collected at a typical rate of 4000 samples per second. Data acquisition using an FM multiplexed analog system and a high-speed personal computer based digital system is described.

  9. Creep-fatigue interaction in aircraft gas turbine components by simulation and testing at scaled temperatures

    Science.gov (United States)

    Sabour, Mohammad Hossein

    Advanced gas turbine engines, which use hot section airfoil cooling, present a wide range of design problems. The frequencies of applied loads and the natural frequencies of the blade also are important since they have significant effects on failure of the component due to fatigue phenomenon. Due to high temperature environment the thermal creep and fatigue are quite severe. One-dimensional creep model, using ANSYS has been formulated in order to predict the creep life of a gas turbine engine blade. Innovative mathematical models for the prediction of the operating life of aircraft components, specifically gas turbine blades, which are subjected to creep-fatigue at high temperatures, are proposed. The components are modeled by FEM, mathematically, and using similitude principles. Three models have been suggested and evaluated numerically and experimentally. Using FEM method for natural frequencies causes phenomena such as curve veering which is studied in more detail. The simulation studies on the life-limiting modes of failure, as well as estimating the expected lifetime of the blade, using the proposed models have been carried out. Although the scale model approach has been used for quite some time, the thermal scaling has been used in this study for the first time. The only thermal studies in literature using scaling for structures is by NASA in which materials of both the prototype and the model are the same, but in the present study materials also are different. The finite element method is employed to model the structure. Because of stress redistribution due to the creep process, it is necessary to include a full inelastic creep step in the finite element formulation. Otherwise over-conservative creep life predictions will be estimated if only the initial elastic stresses are considered. The experimental investigations are carried out in order to validate the models. The main contributions in the thesis are: (1) Using similitude theory for life prediction of

  10. Analytical redundancy management mechanization and flight data analysis for the F-8 digital fly-by-wire aircraft flight control sensors

    Science.gov (United States)

    Deckert, J. C.

    1983-01-01

    The details are presented of an onboard digital computer algorithm designed to reliably detect and isolate the first failure in a duplex set of flight control sensors aboard the NASA F-8 digital fly-by-wire aircraft. The algorithm's successful flight test program is summarized, and specific examples are presented of algorithm behavior in response to software-induced signal faults, both with and without aircraft parameter modeling errors.

  11. Speeding Up

    Institute of Scientific and Technical Information of China (English)

    YU SHUJUN

    2010-01-01

    In the wake of the global financial crisis, China has amazed the world with the speed of its economic recovery. But what has been even more surprising is the speed of its railway evolution. The unveiling of the 1,069-km Wuhan-Guangzhou High-speed Railway on December 26, 2009 pushed China's high-speed rail sys-tem-the total mileage, the average speed and the technology-to rank first in the world almost overnight.

  12. Wind Information Uplink to Aircraft Performing Interval Management Operations

    Science.gov (United States)

    Ahmad, Nashat N.; Barmore, Bryan E.; Swieringa, Kurt A.

    2016-01-01

    Interval Management (IM) is an ADS-B-enabled suite of applications that use ground and flight deck capabilities and procedures designed to support the relative spacing of aircraft (Barmore et al., 2004, Murdoch et al. 2009, Barmore 2009, Swieringa et al. 2011; Weitz et al. 2012). Relative spacing refers to managing the position of one aircraft to a time or distance relative to another aircraft, as opposed to a static reference point such as a point over the ground or clock time. This results in improved inter-aircraft spacing precision and is expected to allow aircraft to be spaced closer to the applicable separation standard than current operations. Consequently, if the reduced spacing is used in scheduling, IM can reduce the time interval between the first and last aircraft in an overall arrival flow, resulting in increased throughput. Because IM relies on speed changes to achieve precise spacing, it can reduce costly, low-altitude, vectoring, which increases both efficiency and throughput in capacity-constrained airspace without negatively impacting controller workload and task complexity. This is expected to increase overall system efficiency. The Flight Deck Interval Management (FIM) equipment provides speeds to the flight crew that will deliver them to the achieve-by point at the controller-specified time, i.e., assigned spacing goal, after the target aircraft crosses the achieve-by point (Figure 1.1). Since the IM and target aircraft may not be on the same arrival procedure, the FIM equipment predicts the estimated times of arrival (ETA) for both the IM and target aircraft to the achieve-by point. This involves generating an approximate four-dimensional trajectory for each aircraft. The accuracy of the wind data used to generate those trajectories is critical to the success of the IM operation. There are two main forms of uncertainty in the wind information used by the FIM equipment. The first is the accuracy of the forecast modeling done by the weather

  13. Shrinkage of magnetosphere observed by TC-1 satellite during the high-speed solar wind stream

    Institute of Scientific and Technical Information of China (English)

    LI LiuYuan; CAO JinBin; ZHOU GuoCheng; YANG JunYing; YAN ChunXiao; ZHANG TieLong; H. REME; I. DANDOURAS; C. M. CARR

    2008-01-01

    During the interval 06:14-07:30 UT on August 24, 2005, since the Earth's magneto-pause was suddenly compressed by the persistent high-speed solar wind stream with the southward component of the interplanetary magnetic field (IMF), the magnetopause moved Inward for about 3.1 RE. Meanwhile, TC-1 satellite shifted from northern plasma sheet to the northern lobe/mantle region, although it kept Inward flying during the Interval 06:00-07:30UT. The shift of TC-1 from the plasma sheet to the lobe/mantle is caused by the simultaneous inward displacements of the plasma sheet and near-Earth lobe/mantle region, and their inward movement velocity is larger than the inward motion velocity of TC-1. The Joint inward dis-placements of the magnetopause, the lobe/mantle region and the plasma sheet indicate that the whole magnetosphere shrinks inward due to the magnetospheric compression by the high-speed solar wind stream, and the magnetospheric ions are attached to the magnetic field lines (i.e. 'frozen' in magnetic field) and move inward in the shrinking process of magnetosphere. The large shrinkage of magne-tosphere indicates that the near-Earth magnetotail compression caused by the strong solar wind dynamic pressure is much larger than its thickening caused by the southward component of the IMF, and the locations of magnetospheric regions with different plasmas vary remarkably with the variation of the solar wind dynamic pressure.

  14. Dynamic response analysis of single-span guideway caused by high speed maglev train

    OpenAIRE

    2011-01-01

    High speed maglev is one of the most important reformations in the ground transportation systems because of its no physical contact nature. This paper intends to study the dynamic response of the single-span guideway induced by moving maglev train. The dynamic model of the maglev train-guideway system is established. In this model, a maglev train consists of three vehicles and each vehicle is regarded as a multibody system with 34 degrees-of-freedom. The guideway is modeled as a simply suppor...

  15. Magnetic field variation caused by rotational speed change in a magnetohydrodynamic dynamo.

    Science.gov (United States)

    Miyagoshi, Takehiro; Hamano, Yozo

    2013-09-20

    We have performed numerical magnetohydrodynamic dynamo simulations in a spherical shell with rotational speed or length-of-day (LOD) variation, which is motivated by correlations between geomagnetic field and climatic variations with ice and non-ice ages. The results show that LOD variation leads to magnetic field variation whose amplitude is considerably larger than that of LOD variation. The heat flux at the outer sphere and the zonal flow also change. The mechanism of the magnetic field variation due to LOD variation is also found. The keys are changes of dynamo activity and Joule heating.

  16. Route toward high-speed nano-magnonics provided by pure spin currents

    Science.gov (United States)

    Divinskiy, B.; Demidov, V. E.; Demokritov, S. O.; Rinkevich, A. B.; Urazhdin, S.

    2016-12-01

    We study experimentally the possibility to utilize pulses of pure spin current, produced via the nonlocal spin injection mechanism, to generate short packets of spin waves propagating in nanoscale magnetic waveguides. Spatially and time-resolved micro-focus Brillouin light scattering spectroscopy measurements demonstrate that the excitation by spin current results in extremely fast transient response, enabling efficient generation of short spin-wave packets with duration down to a few nanoseconds. The proposed method opens a route for the implementation of high-speed magnonic systems for transmission and processing of information on the nanoscale.

  17. Multi-body dynamic system simulation of carrier-based aircraft ski-jump takeoff

    Institute of Scientific and Technical Information of China (English)

    Wang Yangang; Wang Weijun; Qu Xiangju

    2013-01-01

    The flight safety is threatened by the special flight conditions and the low speed of carrier-based aircraft ski-jump takeoff.The aircraft carrier motion,aircraft dynamics,landing gears and wind field of sea state are comprehensively considered to dispose this multidiscipline intersection problem.According to the particular naval operating environment of the carrier-based aircraft ski-jump takeoff,the integrated dynamic simulation models of multi-body system are developed,which involves the movement entities of the carrier,the aircraft and the landing gears,and involves takeoff instruction,control system and the deck wind disturbance.Based on Matlab/Simulink environment,the multi-body system simulation is realized.The validity of the model and the rationality of the result are verified by an example simulation of carrier-based aircraft ski-jump takeoff.The simulation model and the software are suitable for the study of the multidiscipline intersection problems which are involved in the performance,flight quality and safety of carrier-based aircraft takeoff,the effects of landing gear loads,parameters of carrier deck,etc.

  18. Integrated autopilot/autothrottle for the NASA TSRV B-737 aircraft: Design and verification by nonlinear simulation

    Science.gov (United States)

    Bruce, Kevin R.

    1989-01-01

    An integrated autopilot/autothrottle was designed for flight test on the NASA TSRV B-737 aircraft. The system was designed using a total energy concept and is attended to achieve the following: (1) fuel efficiency by minimizing throttle activity; (2) low development and implementation costs by designing the control modes around a fixed inner loop design; and (3) maximum safety by preventing stall and engine overboost. The control law was designed initially using linear analysis; the system was developed using nonlinear simulations. All primary design requirements were satisfied.

  19. Probability distribution of surface wind speed induced by convective adjustment on Venus

    Science.gov (United States)

    Yamamoto, Masaru

    2017-03-01

    The influence of convective adjustment on the spatial structure of Venusian surface wind and probability distribution of its wind speed is investigated using an idealized weather research and forecasting model. When the initially uniform wind is much weaker than the convective wind, patches of both prograde and retrograde winds with scales of a few kilometers are formed during active convective adjustment. After the active convective adjustment, because the small-scale convective cells and their related vertical momentum fluxes dissipate quickly, the large-scale (>4 km) prograde and retrograde wind patches remain on the surface and in the longitude-height cross-section. This suggests the coexistence of local prograde and retrograde flows, which may correspond to those observed by Pioneer Venus below 10 km altitude. The probability distributions of surface wind speed V during the convective adjustment have a similar form in different simulations, with a sharp peak around ∼0.1 m s-1 and a bulge developing on the flank of the probability distribution. This flank bulge is associated with the most active convection, which has a probability distribution with a peak at the wind speed 1.5-times greater than the Weibull fitting parameter c during the convective adjustment. The Weibull distribution P(> V) (= exp[-(V/c)k]) with best-estimate coefficients of Lorenz (2016) is reproduced during convective adjustments induced by a potential energy of ∼7 × 107 J m-2, which is calculated from the difference in total potential energy between initially unstable and neutral states. The maximum vertical convective heat flux magnitude is proportional to the potential energy of the convective adjustment in the experiments with the initial unstable-layer thickness altered. The present work suggests that convective adjustment is a promising process for producing the wind structure with occasionally generating surface winds of ∼1 m s-1 and retrograde wind patches.

  20. Annealing Characteristics of Ultrafine Grained Low-Carbon Steel Processed by Differential Speed Rolling Method

    Science.gov (United States)

    Hamad, Kotiba; Ko, Young Gun

    2016-05-01

    The annealing behavior of ultrafine grained ferrite in low-carbon steel (0.18 wt pct C) fabricated using a differential speed rolling (DSR) process was examined by observing the microstructural changes by electron backscatter diffraction and transmission electron microscopy. For this purpose, the samples processed by 4-pass DSR at a roll speed ratio of 1:4 for the lower and upper rolls, respectively, were annealed isochronally at temperatures ranging from 698 K to 898 K (425 °C to 625 °C) for 1 hour. The deformed samples exhibited a complex microstructure in the ferrite phase consisting of an equiaxed structure with a mean grain size of ~0.4 µm and a lamellar structure with a mean lamellar width of ~0.35 µm. The texture evolved during deformation was characterized by the rolling and shear components with specific orientations. After annealing at temperatures lower than 798 K (525 °C), the aspect ratio of the deformed grains tended to shift toward a unit corresponding to the equiaxed shape, whereas the grain size remained unchanged as the annealing temperature increased. At temperatures above 798 K (525 °C), however, some grains with a low dislocation density began to appear, suggesting that the starting temperature of static recrystallization in the severely deformed ferrite grains was 798 K (525 °C). The annealing texture of the present sample after heat treatment showed a uniform fiber texture consisting of α- and γ-components.

  1. An electrochemical and high-speed imaging study of micropore decontamination by acoustic bubble entrapment.

    Science.gov (United States)

    Offin, Douglas G; Birkin, Peter R; Leighton, Timothy G

    2014-03-14

    Electrochemical and high-speed imaging techniques are used to study the abilities of ultrasonically-activated bubbles to clean out micropores. Cylindrical pores with dimensions (diameter × depth) of 500 μm × 400 μm (aspect ratio 0.8), 125 μm × 350 μm (aspect ratio 2.8) and 50 μm × 200 μm (aspect ratio 4.0) are fabricated in glass substrates. Each pore is contaminated by filling it with an electrochemically inactive blocking organic material (thickened methyl salicylate) before the substrate is placed in a solution containing an electroactive species (Fe(CN)6(3-)). An electrode is fabricated at the base of each pore and the Faradaic current is used to monitor the decontamination as a function of time. For the largest pore, decontamination driven by ultrasound (generated by a horn type transducer) and bulk fluid flow are compared. It is shown that ultrasound is much more effective than flow alone, and that bulk fluid flow at the rates used cannot decontaminate the pore completely, but that ultrasound can. In the case of the 125 μm pore, high-speed imaging is used to elucidate the cleaning mechanisms involved in ultrasonic decontamination and reveals that acoustic bubble entrapment is a key feature. The smallest pore is used to explore the limits of decontamination and it is found that ultrasound is still effective at this size under the conditions employed.

  2. Optimization of 3D laser scanning speed by use of combined variable step

    Science.gov (United States)

    Garcia-Cruz, X. M.; Sergiyenko, O. Yu.; Tyrsa, Vera; Rivas-Lopez, M.; Hernandez-Balbuena, D.; Rodriguez-Quiñonez, J. C.; Basaca-Preciado, L. C.; Mercorelli, P.

    2014-03-01

    The problem of 3D TVS slow functioning caused by constant small scanning step becomes its solution in the presented research. It can be achieved by combined scanning step application for the fast search of n obstacles in unknown surroundings. Such a problem is of keynote importance in automatic robot navigation. To maintain a reasonable speed robots must detect dangerous obstacles as soon as possible, but all known scanners able to measure distances with sufficient accuracy are unable to do it in real time. So, the related technical task of the scanning with variable speed and precise digital mapping only for selected spatial sectors is under consideration. A wide range of simulations in MATLAB 7.12.0 of several variants of hypothetic scenes with variable n obstacles in each scene (including variation of shapes and sizes) and scanning with incremented angle value (0.6° up to 15°) is provided. The aim of such simulation was to detect which angular values of interval still permit getting the maximal information about obstacles without undesired time losses. Three of such local maximums were obtained in simulations and then rectified by application of neuronal network formalism (Levenberg-Marquradt Algorithm). The obtained results in its turn were applied to MET (Micro-Electro-mechanical Transmission) design for practical realization of variable combined step scanning on an experimental prototype of our previously known laser scanner.

  3. Motor fatigue measurement by distance-induced slow down of walking speed in multiple sclerosis.

    Directory of Open Access Journals (Sweden)

    Rémy Phan-Ba

    Full Text Available BACKGROUND AND RATIONALE: Motor fatigue and ambulation impairment are prominent clinical features of people with multiple sclerosis (pMS. We hypothesized that a multimodal and comparative assessment of walking speed on short and long distance would allow a better delineation and quantification of gait fatigability in pMS. Our objectives were to compare 4 walking paradigms: the timed 25-foot walk (T25FW, a corrected version of the T25FW with dynamic start (T25FW(+, the timed 100-meter walk (T100MW and the timed 500-meter walk (T500MW. METHODS: Thirty controls and 81 pMS performed the 4 walking tests in a single study visit. RESULTS: The 4 walking tests were performed with a slower WS in pMS compared to controls even in subgroups with minimal disability. The finishing speed of the last 100-meter of the T500MW was the slowest measurable WS whereas the T25FW(+ provided the fastest measurable WS. The ratio between such slowest and fastest WS (Deceleration Index, DI was significantly lower only in pMS with EDSS 4.0-6.0, a pyramidal or cerebellar functional system score reaching 3 or a maximum reported walking distance ≤ 4000 m. CONCLUSION: The motor fatigue which triggers gait deceleration over a sustained effort in pMS can be measured by the WS ratio between performances on a very short distance and the finishing pace on a longer more demanding task. The absolute walking speed is abnormal early in MS whatever the distance of effort when patients are unaware of ambulation impairment. In contrast, the DI-measured ambulation fatigability appears to take place later in the disease course.

  4. High-speed neutron radiography for monitoring the water absorption by capillarity in porous materials

    Science.gov (United States)

    Cnudde, Veerle; Dierick, Manuel; Vlassenbroeck, Jelle; Masschaele, Bert; Lehmann, Eberhard; Jacobs, Patric; Van Hoorebeke, Luc

    2008-01-01

    Fluid flow through porous natural building stones is of great importance when studying their weathering processes. Many traditional experiments based on mass changes are available for studying liquid transport in porous stones, such as the determination of the water absorption coefficient by capillarity. Because thermal neutrons experience a strong attenuation by hydrogen, neutron radiography is a suitable technique for the study of water absorption by capillarity in porous stones. However, image contrast can be impaired because hydrogen mainly scatters neutrons rather than absorbing them, resulting in a blurred image. Capillarity results obtained by neutron radiography and by the European Standard 1925 for the determination of the water absorption coefficient by capillarity for natural building stones with a variable porosity were compared. It is illustrated that high-speed neutron radiography can be a useful research tool for the visualization of internal fluid flow inside inorganic building materials such as limestones and sandstones.

  5. Integration of noise control into the product design process : a case study : the Silent Aircraft Initiative

    Energy Technology Data Exchange (ETDEWEB)

    Faszer, A. [Noise Solutions Inc., Calgary, AB (Canada)

    2007-07-01

    The Silent Aircraft Initiative (SAI) is a study being conducted by the Cambridge-MIT Institute to discover ways to significantly reduce aircraft noise. Part of the study focuses on developing aircraft and engine designs that meet the SAI objectives. This presentation included several illustrations of the favoured configuration of a blended wing design, with 4 engines located on the upper surface of a shallow wing which shields engine noise. This presentation described various engine parts such as the low specific thrust turbofan, the variable area nozzle and the acoustic treatment in the intake and exhaust turbomachinery that minimizes noise. The requirements for market viability of the aircraft were discussed as well as the technical challenges in terms of its propulsion systems; structural analysis; mechanical design; low speed aerodynamic performance; cabin layout; and maintenance considerations. It was concluded that the SAI has achieved a credible conceptual aircraft design given the high risk of the technologies used. The project has met objectives of a functionally silent and fuel efficient aircraft. The new conceptual aircraft has potential for fuel burn of 149 pax-miles per imperial gallon and noise of 63 dBA near the perimeter of airports. 1 tab., 48 figs.

  6. Creating a Test Validated Structural Dynamic Finite Element Model of the X-56A Aircraft

    Science.gov (United States)

    Pak, Chan-Gi; Truong, Samson

    2014-01-01

    Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of the Multi Utility Technology Test-bed, X-56A aircraft, is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of the X-56A aircraft. The ground vibration test-validated structural dynamic finite element model of the X-56A aircraft is created in this study. The structural dynamic finite element model of the X-56A aircraft is improved using a model tuning tool. In this study, two different weight configurations of the X-56A aircraft have been improved in a single optimization run. Frequency and the cross-orthogonality (mode shape) matrix were the primary focus for improvement, while other properties such as center of gravity location, total weight, and offdiagonal terms of the mass orthogonality matrix were used as constraints. The end result was a more improved and desirable structural dynamic finite element model configuration for the X-56A aircraft. Improved frequencies and mode shapes in this study increased average flutter speeds of the X-56A aircraft by 7.6% compared to the baseline model.

  7. Creating a Test-Validated Finite-Element Model of the X-56A Aircraft Structure

    Science.gov (United States)

    Pak, Chan-Gi; Truong, Samson

    2014-01-01

    Small modeling errors in a finite-element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of the X-56A Multi-Utility Technology Testbed aircraft is the flight demonstration of active flutter suppression and, therefore, in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of the X-56A aircraft. The ground-vibration test-validated structural dynamic finite-element model of the X-56A aircraft is created in this study. The structural dynamic finite-element model of the X-56A aircraft is improved using a model-tuning tool. In this study, two different weight configurations of the X-56A aircraft have been improved in a single optimization run. Frequency and the cross-orthogonality (mode shape) matrix were the primary focus for improvement, whereas other properties such as c.g. location, total weight, and off-diagonal terms of the mass orthogonality matrix were used as constraints. The end result was an improved structural dynamic finite-element model configuration for the X-56A aircraft. Improved frequencies and mode shapes in this study increased average flutter speeds of the X-56A aircraft by 7.6% compared to the baseline model.

  8. Accumulative deformation in railway track induced by high-speed traffic loading of the trains

    Institute of Scientific and Technical Information of China (English)

    Bian Xuecheng; Jiang Hongguang; Chen Yunmin

    2010-01-01

    Prediction and control of the permanent settlement of a track caused by traffic loading from trains is crucial to high-speed railway design and maintenance. In this study, a unified prediction model of accumulative deformation of geomaterials used in railway construction subjected to cyclic loadings is introduced and calibrated using physical model testing. Based on this versatile model, a calculation approach to determine the track structure settlement under repeated loadings caused by the movement of the wheel axle of the train is proposed. Regression analysis on the physical model testing is adopted to determine the parameters involved in the computational approach. Comparison of model test data and computed results shows that the parameters obtained from the back-analysis are consistent throughout the various testing conditions, and the proposed calculation approach is capable of satisfactorily predicting the accumulative settlement of the railway roadbed and subgrade soil for various axle loads and loading cycles. A case study of a high-speed railway is performed to demonstrate the feasibility of the proposed approach in realistic engineering applications. The computation results from the settlement development of a roadbed and subgrade soil are presented and discussed.

  9. Quality evaluation of energy consumed in flow regulation method by speed variation in centrifugal pumps

    Science.gov (United States)

    Morales, S.; Culman, M.; Acevedo, C.; Rey, C.

    2014-06-01

    Nowadays, energy efficiency and the Electric Power Quality are two inseparable issues in the evaluation of three-phase induction motors, framed within the program of Rational and Efficient Use of Energy (RUE).The use of efficient energy saving devices has been increasing significantly in RUE programs, for example the use of variable frequency drives (VFD) in pumping systems.The overall objective of the project was to evaluate the impact on power quality and energy efficiency in a centrifugal pump driven by an induction three-phase motor, using the flow control method of speed variation by VFD. The fundamental purpose was to test the opinions continuously heard about the use of flow control methods in centrifugal pumps, analyzing the advantages and disadvantages that have been formulated deliberately in order to offer support to the industry in taking correct decisions. The VFD changes the speed of the motor-pump system increasing efficiency compared to the classical methods of regulation. However, the VFD originates conditions that degrade the quality of the electric power supplied to the system and therefore its efficiency, due to the nonlinearity and presence of harmonic currents. It was possible to analyze the power quality, ensuring that the information that comes to the industry is generally biased.

  10. Speed up linear scan in high-dimensions by sorting one-dimensional projections

    Directory of Open Access Journals (Sweden)

    Jiangtao Cui

    2011-06-01

    Full Text Available High-dimensional indexing is a pervasive challenge faced in multimedia retrieval. Existing indexing methods applying linear scan strategy, such as VA-file and its variations, are still efficient when the dimensionality is high. In this paper, we propose a new access idea implemented on linear scan based methods to speed up the nearest-neighbor queries. The idea is to map high-dimensional points into two kinds of one-dimensional values using projection and distance computation. The projection values on the line determined by the first Principal Component are sorted and indexed using a B+-tree, and the distances of each point to a reference point are also embedded into leaf node of the B+-tree. When performing nearest neighbor search, the Partial Distortion Searching and triangular inequality are employed to prune search space. In the new search algorithm, only a small portion of data points need to be linearly accessed by computing the bounded distance on the one-dimensional line, which can reduce the I/O and processor time dramatically. Experiment results on large image databases show that the new access method provides a faster search speed than existing high-dimensional index methods.

  11. Preparative separation of grape skin polyphenols by high-speed counter-current chromatography.

    Science.gov (United States)

    Luo, Lanxin; Cui, Yan; Zhang, Shuting; Li, Lingxi; Li, Yuanyuan; Zhou, Peiyu; Sun, Baoshan

    2016-12-01

    To develop an efficient method for large preparation of various individual polyphenols from white grape skins (Fernão Pires; Vitis vinifera) by preparative high-speed counter-current chromatography (HSCCC) and preparative-HPLC, an optimized preparative HSCCC condition with two-phase solvent system composed of Hex-EtOAc-H2O (1:50:50, v/v) was used to separate grape skin polyphenols into various fractions. Both the tail-head and head-tail elution modes were used with a flow rate of 3.0ml/min and a rotary speed of 950rpm. Afterwards, a preparative-HPLC separation was applied to isolate individual polyphenols in each of the fractions from HSCCC. Total of 7 fractions (Fraction A to G) were obtained from grape skin extract by HSCCC. After preparative-HPLC isolation, fifteen individual compounds were obtained, most of which presented high yields and purity (all over 90%). The HSCCC method followed with preparative-HPLC appeared to be convenient and economical, constituting an efficient strategy for the isolation of grape skin polyphenols.

  12. Fatigue Behavior of High Speed Steel Roll Materials for Hot Rolling by Laser Impacting

    Institute of Scientific and Technical Information of China (English)

    ZHOU Li; SUN Da-le; LIU Chang-sheng; WU Qiong

    2006-01-01

    The fatigue behavior of high speed steel (HSS) roll materials for hot rolling was researched under water-cooling conditions by laser impacting. The microstructure of HSS sample and the morphologies of fatigue samples were observed by scanning electron microscope. The phase structure was detected by XRD. The morphology of situ oxide scale was observed by optical microscope, and the expansion coefficient was measured by TGA. The experiment results indicate that the cracks come into being at the carbide-matrix interface, but there are no cracks in the matrix after many times of laser impacting treatment, for the situ sample taken from the fractured roll surface, big carbides are more sensitive to the fatigue, and peel off prior to small ones. The relevant fatigue mechanisms are also discussed.

  13. A survey of jet aircraft PM by TEM in APEX III

    Science.gov (United States)

    Huang, Chung-Hsuan; Bryg, Victoria M.; Vander Wal, Randy L.

    2016-09-01

    Results are reported for sampling non-volatile particulate matter from field tests during the NASA led APEX III campaign. This paper reports observations of particulate emissions collected from a suite of jet engine aircraft to assess differences and similarities in soot macro- micro- and nanostructure using TEM. Aggregates are compact, primary particle sizes varied and nanostructure is mixed. Comparisons are made to soot from a laboratory flame as a well-studied reference. Results are interpreted in terms of turbulence interacting with the different stages of particle formation and growth with implications for atmospheric processing and climate impact.

  14. A Survey of Jet Aircraft PM by TEM in APEX III

    Science.gov (United States)

    VanderWal, Randy L.; Bryg, Victoria M.

    2014-01-01

    Based upon field testing during the NASA led APEX III campaign conducted in November 2005 at the NASA Glenn Research Center in coordination with Continental Airlines and Cleveland Hopkins International Airport. This paper reports observations of particulate emissions collected from a suite of jet engine aircraft to assess differences and similarities in soot macro- micro- and nanostructure using transmission electron microscopy (TEM). Aggregates are compact, primary particle sizes varied and nanostructure mixed. Comparisons are made to more familiar laboratory flame-generated soot as a well-studied point of reference. Results are interpreted in terms of turbulence interacting with the different stages of particle formation and growth.

  15. The European Research Infrastructure IAGOS - From dedicated field studies to routine observations of the atmosphere by instrumented passenger aircraft

    Science.gov (United States)

    Petzold, Andreas; Volz-Thomas, Andreas; Gerbig, Christoph; Thouret, Valerie; Cammas, Jean-Pierre; Brenninkmeijer, Carl A. M.; Iagos Team

    2013-04-01

    The global distribution of trace species is controlled by a complex interplay between natural and anthropogenic sources and sinks, atmospheric short- to long-range transport, and in future by diverse, largely not yet quantified feedback mechanisms such as enhanced evaporation of water vapour in a warming climate or possibly the release of methane from melting marine clathrates. Improving global trace gas budgets and reducing the uncertainty of climate predictions crucially requires representative data from routine long-term observations as independent constraint for the evaluation and improvement of model parameterizations. IAGOS (In-service Aircraft for a Global Observing System; www.iagos.org) is a new European Research Infrastructure which operates a unique global observing system by deploying autonomous instruments aboard a fleet of passenger aircraft. IAGOS consists of two complementary building blocks: IAGOS-CORE deploys newly developed high-tech instrumentation for regular in-situ measurements of atmospheric chemical species (O3, CO, CO2, NOx, NOy, H2O, CH4), aerosols and cloud particles. Involved airlines ensure global operation of the network. In IAGOS-CARIBIC a cargo container is operated as a flying laboratory aboard one passenger aircraft. IAGOS aims at the provision of long-term, frequent, regular, accurate, and spatially resolved in-situ observations of the atmospheric chemical composition in the UTLS and the extra tropical troposphere and on vertical profiles of greenhouse gases, reactive trace gases and aerosols throughout the troposphere. It builds on almost 20 years of scientific and technological expertise gained in the research projects MOZAIC (Measurement of Ozone and Water Vapour on Airbus In-service Aircraft) and CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container). The European consortium includes research centres, universities, national weather services, airline operators and aviation

  16. Observation of fine particle aggregating behavior induced by high intensity conditioning using high speed CCD

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The aggregating behavior between bubbles and particles induced by high intensity conditioning (HIC) was studied using high speed CCD technique. Bubble size measurement was conducted, and the attachment behavior between bubbles and particles in HIC cell and flotation cell were observed. The results show that in HIC cell, high intensity conditioning creates an advantage environment for the formation of small size bubble due to hydrodynamic cavitations, and these fine bubbles have high probability of bubble-particle collision,which will enhance fine particle flotation. The bubble-particle attachment experiments indicate that in high intensity conditioning cell, a lot of fine bubbles are produced in situ on the surface of fine particles, and most of fine particles are aggregated under the bridging action of fine bubbles. The observation of bubble-particle interaction in flotation cell illustrates that aggregates created by HIC can be loaded more easily by big air bubble in flotation cell than those created by normal conditioning.

  17. Preparative Isolation of Three Anthraquinones from Rumex japonicus by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Shuying Guo

    2011-01-01

    Full Text Available Three anthraquinones—emodin, chrysophanol, and physcion—were successfully purified from the dichloromethane extract of the Chinese medicinal herb Rumex japonicus by high-speed counter-current chromatography (HSCCC. The extract was separated with n-hexane–ethanol–water (18:22:3, v/v/v as the two-phase solvent system and yielded 3.4 mg of emodin, 24.1 mg of chrysophanol, and 2.0 mg of physcion from 500 mg of sample with purities of 99.2 %, 98.8% and 98.2%, respectively. The HSCCC fractions were analyzed by high-performance liquid chromatography (HPLC and the chemical structures of the three anthraquinones were confirmed by 1H-NMR and 13C-NMR analysis. This is the first time these anthraquinones have been obtained from R. japonicus by HSCCC.

  18. Aerial navigation : on the problem of guiding aircraft in a fog or by night when there is no visibility

    Science.gov (United States)

    Loth, William

    1922-01-01

    The use of magnetic fields and wire to navigate aircraft in conditions of poor visibility is presented. This field may be considered to be derived from a double lemniscate, considered in the particular case where the origin is a double point formed from the magnetic field of the slack wire, from the field produced by the return currents and from the field due to the currents induced in the conducting mass. These fields are dephased in two ways, one in the direction of the wire, the other in a direction perpendicular to it.

  19. Residents' Annoyance Responses to Aircraft Noise Events

    OpenAIRE

    United States, National Aeronautics and Space Administration

    1983-01-01

    In a study conducted in the vicinity of Salt Lake City International Airport, community residents reported their annoyance with individual aircraft flyovers during rating sessions conducted in their homes. Annoyance ratings were obtained at different times of the day. Aircraft noise levels were measured, and other characteristics of the aircraft were noted by trained observers. Metrics commonly used for assessing aircraft noise were compared, but none performed significantly better than A-...

  20. High speed intelligent classifier of tomatoes by colour, size and weight

    Energy Technology Data Exchange (ETDEWEB)

    Cement, J.; Novas, N.; Gazquez, J. A.; Manzano-Agugliaro, F.

    2012-11-01

    At present most horticultural products are classified and marketed according to quality standards, which provide a common language for growers, packers, buyers and consumers. The standardisation of both product and packaging enables greater speed and efficiency in management and marketing. Of all the vegetables grown in greenhouses, tomatoes are predominant in both surface area and tons produced. This paper will present the development and evaluation of a low investment classification system of tomatoes with these objectives: to put it at the service of producing farms and to classify for trading standards. An intelligent classifier of tomatoes has been developed by weight, diameter and colour. This system has optimised the necessary algorithms for data processing in the case of tomatoes, so that productivity is greatly increased, with the use of less expensive and lower performance electronics. The prototype is able to achieve very high speed classification, 12.5 ratings per second, using accessible and low cost commercial equipment for this. It decreases fourfold the manual sorting time and is not sensitive to the variety of tomato classified. This system facilitates the processes of standardisation and quality control, increases the competitiveness of tomato farms and impacts positively on profitability. The automatic classification system described in this work represents a contribution from the economic point of view, as it is profitable for a farm in the short term (less than six months), while the existing systems, can only be used in large trading centers. (Author) 36 refs.

  1. The response of collision speed caused by the large bus to new flexible barrier

    Institute of Scientific and Technical Information of China (English)

    Lei Zhengbao; Wang Rui

    2014-01-01

    In order to study the response of collision speed caused by the large bus to new flexible barrier,in this paper,with the large bus as the carrier,the full-scale impact tests between flexible barrier and vehicle with the impact velocities of 40 km/h and 60 km/h were carried out separately,following the procedures of the test preparation,test processing,data acquisition, etc,which were based on the test platform of the Large Structure Crash Testing Laboratory of Changsha University of Science and Technology. The important test results which contain the damage of vehicles and barrier,the moving locus of vehicle,the occupant risk index,the maxi-mum dynamic deformation, etc,were obtained through the analysis under the different collision speeds. These provide the necessary reference basis for the further research on the structure topology optimization and im-prove the comprehensive constraint performance to the flexible barrier.

  2. Speeding up Monte Carlo molecular simulation by a non-conservative early rejection scheme

    KAUST Repository

    Kadoura, Ahmad Salim

    2015-04-23

    Monte Carlo (MC) molecular simulation describes fluid systems with rich information, and it is capable of predicting many fluid properties of engineering interest. In general, it is more accurate and representative than equations of state. On the other hand, it requires much more computational effort and simulation time. For that purpose, several techniques have been developed in order to speed up MC molecular simulations while preserving their precision. In particular, early rejection schemes are capable of reducing computational cost by reaching the rejection decision for the undesired MC trials at an earlier stage in comparison to the conventional scheme. In a recent work, we have introduced a ‘conservative’ early rejection scheme as a method to accelerate MC simulations while producing exactly the same results as the conventional algorithm. In this paper, we introduce a ‘non-conservative’ early rejection scheme, which is much faster than the conservative scheme, yet it preserves the precision of the method. The proposed scheme is tested for systems of structureless Lennard-Jones particles in both canonical and NVT-Gibbs ensembles. Numerical experiments were conducted at several thermodynamic conditions for different number of particles. Results show that at certain thermodynamic conditions, the non-conservative method is capable of doubling the speed of the MC molecular simulations in both canonical and NVT-Gibbs ensembles. © 2015 Taylor & Francis

  3. Quantitative analysis of vocal fold vibration during register change by high-speed digital imaging system

    Science.gov (United States)

    Kumada, Masanobu; Kobayashi, Noriko; Hirose, Hajime; Tayama, Niro; Imagawa, Hiroshi; Sakakibara, Ken-Ichi; Nito, Takaharu; Kakurai, Shin'ichi; Kumada, Chieko; Wada, Mamiko; Niimi, Seiji

    2002-05-01

    The physiological study of prosody is indispensable in terms not only of the physiological interest but also of the evaluation and treatment for pathological cases of prosody. In free talk, the changes of vocal fold vibration are found frequently and these phenomena are very important prosodic events. To analyze quantitatively the vocal fold vibration at the register change as the model of prosodic event, our high-speed digital imaging system was used at a rate of 4500 images of 256-256 pixels per second. Four healthy Japanese adults (2 males and 2 females) were served as subjects. Tasks were sustained phonation containing register changes. Two major categories (Category A and B) were found in the ways of changing of vocal fold vibrations at the register change. In Category A, changes were very smooth in terms of the vocal fold vibration. In Category B, changes were not so smooth with some additional events at the register change, such as the anterior-posterior phase difference of the vibration, the abduction of the vocal folds, or the interruption of the phonation. The number of the subtypes for Category B is thought to increase if more subjects with a wider range of variety are analyzed. For the study of prosody, our high-speed digital imaging system is a very powerful tool by which physiological information can be obtained.

  4. Trading speed and accuracy by coding time: a coupled-circuit cortical model.

    Directory of Open Access Journals (Sweden)

    Dominic Standage

    2013-04-01

    Full Text Available Our actions take place in space and time, but despite the role of time in decision theory and the growing acknowledgement that the encoding of time is crucial to behaviour, few studies have considered the interactions between neural codes for objects in space and for elapsed time during perceptual decisions. The speed-accuracy trade-off (SAT provides a window into spatiotemporal interactions. Our hypothesis is that temporal coding determines the rate at which spatial evidence is integrated, controlling the SAT by gain modulation. Here, we propose that local cortical circuits are inherently suited to the relevant spatial and temporal coding. In simulations of an interval estimation task, we use a generic local-circuit model to encode time by 'climbing' activity, seen in cortex during tasks with a timing requirement. The model is a network of simulated pyramidal cells and inhibitory interneurons, connected by conductance synapses. A simple learning rule enables the network to quickly produce new interval estimates, which show signature characteristics of estimates by experimental subjects. Analysis of network dynamics formally characterizes this generic, local-circuit timing mechanism. In simulations of a perceptual decision task, we couple two such networks. Network function is determined only by spatial selectivity and NMDA receptor conductance strength; all other parameters are identical. To trade speed and accuracy, the timing network simply learns longer or shorter intervals, driving the rate of downstream decision processing by spatially non-selective input, an established form of gain modulation. Like the timing network's interval estimates, decision times show signature characteristics of those by experimental subjects. Overall, we propose, demonstrate and analyse a generic mechanism for timing, a generic mechanism for modulation of decision processing by temporal codes, and we make predictions for experimental verification.

  5. Scorpion: Close Air Support (CAS) aircraft

    Science.gov (United States)

    Allen, Chris; Cheng, Rendy; Koehler, Grant; Lyon, Sean; Paguio, Cecilia

    1991-01-01

    The objective is to outline the results of the preliminary design of the Scorpion, a proposed close air support aircraft. The results obtained include complete preliminary analysis of the aircraft in the areas of aerodynamics, structures, avionics and electronics, stability and control, weight and balance, propulsion systems, and costs. A conventional wing, twin jet, twin-tail aircraft was chosen to maximize the desirable characteristics. The Scorpion will feature low speed maneuverability, high survivability, low cost, and low maintenance. The life cycle cost per aircraft will be 17.5 million dollars. The maximum takeoff weight will be 52,760 pounds. Wing loading will be 90 psf. The thrust to weight will be 0.6 lbs/lb. This aircraft meets the specified mission requirements. Some modifications have been suggested to further optimize the design.

  6. Femtoliter-scale patterning by high-speed, highly scaled inverse gravure printing.

    Science.gov (United States)

    Kitsomboonloha, Rungrot; Morris, S J S; Rong, Xiaoying; Subramanian, Vivek

    2012-12-01

    Pattern printing techniques have advanced rapidly in the past decade, driven by their potential applications in printed electronics. Several printing techniques have realized printed features of 10 μm or smaller, but unfortunately, they suffer from disadvantages that prevent their deployment in real applications; in particular, process throughput is a significant concern. Direct gravure printing is promising in this regard. Gravure printing delivers high throughput and has a proven history of being manufacturing worthy. Unfortunately, it suffers from scalability challenges because of limitations in roll manufacturing and limited understanding of the relevant printing mechanisms. Gravure printing involves interactions between the ink, the patterned cylinder master, the doctor blade that wipes excess ink, and the substrate to which the pattern is transferred. As gravure-printed features are scaled, the associated complexities are increased, and a detailed study of the various processes involved is lacking. In this work, we report on various gravure-related fluidic mechanisms using a novel highly scaled inverse direct gravure printer. The printer allows the overall pattern formation process to be studied in detail by separating the entire printing process into three sequential steps: filling, wiping, and transferring. We found that pattern formation by highly scaled gravure printing is governed by the wettability of the ink to the printing plate, doctor blade, and substrate. These individual functions are linked by the apparent capillary number (Ca); the printed volume fraction (φ(p)) of a feature can be constructed by incorporating these basis functions. By relating Ca and φ(p), an optimized operating point can be specified, and the associated limiting phenomena can be identified. We used this relationship to find the optimized ink viscosity and printing speed to achieve printed polymer lines and line spacings as small as 2 μm at printing speeds as high as ∼1 m/s.

  7. Policy and the evaluation of aircraft noise

    NARCIS (Netherlands)

    Kroesen, M.; Molin, E.J.E.; Van Wee, G.P.

    2010-01-01

    In this paper, we hypothesize and test the ideas that (1) people’s subjectivity in relation to aircraft noise is shaped by the policy discourse, (2) this results in a limited number of frames towards aircraft noise, (3) the frames inform people how to think and feel about aircraft noise and (4) the

  8. Annoyance caused by advanced turboprop aircraft flyover noise: Single-rotating propeller configuration

    Science.gov (United States)

    Mccurdy, David A.

    1988-01-01

    Two experiments were conducted to quantify the annoyance of people to advanced turboprop (propfan) aircraft flyover noise. The objectives were to: (1) determine the effects on annoyance of various tonal characteristics; and (2) compare annoyance to advanced turboprops with annoyance to conventional turboprops and jets. A computer was used to produce realistic, time-varying simulations of advanced turboprop aircraft takeoff noise. In the first experiment, subjects judged the annoyance of 45 advanced turboprop noises in which the tonal content was systematically varied to represent the factorial combinations of five fundamental frequencies, three frequency envelope shapes, and three tone-to-broadband noise ratios. Each noise was presented at three sound levels. In the second experiment, 18 advanced turboprop takeoffs, 5 conventional turboprop takeoffs, and 5 conventional jet takeoffs were presented at three sound pressure levels to subjects. Analysis indicated that frequency envelope shape did not significantly affect annoyance. The interaction of fundamental frequency with tone-to-broadband noise ratio did have a large and complex effect on annoyance. The advanced turboprop stimuli were slightly less annoying than the conventional stimuli.

  9. Model-based aviation advice on distal volcanic ash clouds by assimilating aircraft in situ measurements

    Science.gov (United States)

    Fu, Guangliang; Heemink, Arnold; Lu, Sha; Segers, Arjo; Weber, Konradin; Lin, Hai-Xiang

    2016-07-01

    The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts in these distal areas. In our approach, we use real-life aircraft in situ observations, measured in the northwestern part of Germany during the 2010 Eyjafjallajökull eruption, in an ensemble-based data assimilation system combined with a volcanic ash transport model to investigate the potential improvement on the forecast accuracy with regard to the distal volcanic ash plume. We show that the error of the analyzed volcanic ash state can be significantly reduced through assimilating real-life in situ measurements. After a continuous assimilation, it is shown that the aviation advice for Germany, the Netherlands and Luxembourg can be significantly improved. We suggest that with suitable aircrafts measuring once per day across the distal volcanic ash plume, the description and prediction of volcanic ash clouds in these areas can be greatly improved.

  10. Breaking and Characteristics of Ganoderma Lucidum Spores by High Speed Entrifugal Shearing Pulverizer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The spores of Ganoderma lucidum were ground and broken to ultrafine particles by high speed centrifugal shearing(HSCS) pulverizer. The characteristics of Ganoderma lucidum spores were analyzed by scanning electron microscope (SEM), Fourier transform infrared spectrophotometry (FTIR). Ultraviolet-visible pectrophotometer was used to determine the extraction ratio of aqueous solubility polysaccharide between the raw and broken spores. The immunological function on the mice before and after the breaking of spores was investigated. The experimental results show that after being ground, the sporoderm-broken ratio reachs 100%,the original active ingredients of ganoderma lucidum spores do not change, and the extraction ratio of aqueous solubility polysaccharide is greatly increased by 40.08%. The broken spores show much higher immunological activity comparing with original spores of Ganoderma lucidum.

  11. High speed roll casting of Mg alloy strip by a vertical type twin roll caster

    OpenAIRE

    H.Watari; S. Kumai; Haga, T.

    2006-01-01

    Purpose: The possibility of high speed roll casting of AZ31, AM60 and AZ91 was investigated. Warm deep drawing of roll cast magnesium alloy was operated. and formability of roll cast magnesium strip was cleared.Design/methodology/approach: A vertical type high speed twin roll caster was used. The roll casting was operated in the air atmosphere. The casting speed was from 60 m/min up to 180 m/min. Low temperature casting was adopted to realize high speed casting.Findings: Strip thinner 3 mm wi...

  12. Speed and Vibration Performance as well as Obstacle Avoidance Performance of Electric Wheel Chair Controlled by Human Eyes Only

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2014-01-01

    Full Text Available Speed and vibration performance as well as obstacle avoidance performance of the previously proposed Electric Wheel Chair: EWC controlled by human eyes only is conducted. Experimental results show acceptable performances of speed vibration performance as well as obstacle avoidance performance for disabled persons. More importantly, disabled persons are satisfied with the proposed EWC because it works by their eyes only. Without hands and finger, they can control EWC freely.

  13. Shrinkage of magnetosphere observed by TC-1 satellite during the high-speed solar wind stream

    Institute of Scientific and Technical Information of China (English)

    H.; RME; I.; DANDOURAS; C.; M.; CARR

    2008-01-01

    During the interval 06:14―07:30 UT on August 24, 2005, since the Earth’s magneto- pause was suddenly compressed by the persistent high-speed solar wind stream with the southward component of the interplanetary magnetic field (IMF), the magnetopause moved inward for about 3.1 RE. Meanwhile, TC-1 satellite shifted from northern plasma sheet to the northern lobe/mantle region, although it kept inward flying during the interval 06:00―07:30UT. The shift of TC-1 from the plasma sheet to the lobe/mantle is caused by the simultaneous inward displacements of the plasma sheet and near-Earth lobe/mantle region, and their inward movement velocity is larger than the inward motion velocity of TC-1. The joint inward dis-placements of the magnetopause, the lobe/mantle region and the plasma sheet indicate that the whole magnetosphere shrinks inward due to the magnetospheric compression by the high-speed solar wind stream, and the magnetospheric ions are attached to the magnetic field lines (i.e. ‘frozen’ in magnetic field) and move inward in the shrinking process of magnetosphere. The large shrinkage of magne-tosphere indicates that the near-Earth magnetotail compression caused by the strong solar wind dynamic pressure is much larger than its thickening caused by the southward component of the IMF, and the locations of magnetospheric regions with different plasmas vary remarkably with the variation of the solar wind dynamic pressure.

  14. High-speed quantum-random number generation by continuous measurement of arrival time of photons

    Science.gov (United States)

    Yan, Qiurong; Zhao, Baosheng; Hua, Zhang; Liao, Qinghong; Yang, Hao

    2015-07-01

    We demonstrate a novel high speed and multi-bit optical quantum random number generator by continuously measuring arrival time of photons with a common starting point. To obtain the unbiased and post-processing free random bits, the measured photon arrival time is converted into the sum of integral multiple of a fixed period and a phase time. Theoretical and experimental results show that the phase time is an independent and uniform random variable. A random bit extraction method by encoding the phase time is proposed. An experimental setup has been built and the unbiased random bit generation rate could reach 128 Mb/s, with random bit generation efficiency of 8 bits per detected photon. The random numbers passed all tests in the statistical test suite.

  15. Study of cavitation bubble dynamics during Ho:YAG laser lithotripsy by high-speed camera

    Science.gov (United States)

    Zhang, Jian J.; Xuan, Jason R.; Yu, Honggang; Devincentis, Dennis

    2016-02-01

    Although laser lithotripsy is now the preferred treatment option for urolithiasis, the mechanism of laser pulse induced calculus damage is still not fully understood. This is because the process of laser pulse induced calculus damage involves quite a few physical and chemical processes and their time-scales are very short (down to sub micro second level). For laser lithotripsy, the laser pulse induced impact by energy flow can be summarized as: Photon energy in the laser pulse --> photon absorption generated heat in the water liquid and vapor (super heat water or plasma effect) --> shock wave (Bow shock, acoustic wave) --> cavitation bubble dynamics (oscillation, and center of bubble movement , super heat water at collapse, sonoluminscence) --> calculus damage and motion (calculus heat up, spallation/melt of stone, breaking of mechanical/chemical bond, debris ejection, and retropulsion of remaining calculus body). Cavitation bubble dynamics is the center piece of the physical processes that links the whole energy flow chain from laser pulse to calculus damage. In this study, cavitation bubble dynamics was investigated by a high-speed camera and a needle hydrophone. A commercialized, pulsed Ho:YAG laser at 2.1 mu;m, StoneLightTM 30, with pulse energy from 0.5J up to 3.0 J, and pulse width from 150 mu;s up to 800 μs, was used as laser pulse source. The fiber used in the investigation is SureFlexTM fiber, Model S-LLF365, a 365 um core diameter fiber. A high-speed camera with frame rate up to 1 million fps was used in this study. The results revealed the cavitation bubble dynamics (oscillation and center of bubble movement) by laser pulse at different energy level and pulse width. More detailed investigation on bubble dynamics by different type of laser, the relationship between cavitation bubble dynamics and calculus damage (fragmentation/dusting) will be conducted as a future study.

  16. Meeting Air Transportation Demand in 2025 by Using Larger Aircraft and Alternative Routing to Complement NextGen Operational Improvements

    Science.gov (United States)

    Smith, Jeremy C.; Guerreiro, Nelson M.; Viken, Jeffrey K.; Dollyhigh, Samuel M.; Fenbert, James W.

    2010-01-01

    A study was performed that investigates the use of larger aircraft and alternative routing to complement the capacity benefits expected from the Next Generation Air Transportation System (NextGen) in 2025. National Airspace System (NAS) delays for the 2025 demand projected by the Transportation Systems Analysis Models (TSAM) were assessed using NASA s Airspace Concept Evaluation System (ACES). The shift in demand from commercial airline to automobile and from one airline route to another was investigated by adding the route delays determined from the ACES simulation to the travel times used in the TSAM and re-generating new flight scenarios. The ACES simulation results from this study determined that NextGen Operational Improvements alone do not provide sufficient airport capacity to meet the projected demand for passenger air travel in 2025 without significant system delays. Using larger aircraft with more seats on high-demand routes and introducing new direct routes, where demand warrants, significantly reduces delays, complementing NextGen improvements. Another significant finding of this study is that the adaptive behavior of passengers to avoid congested airline-routes is an important factor when projecting demand for transportation systems. Passengers will choose an alternative mode of transportation or alternative airline routes to avoid congested routes, thereby reducing delays to acceptable levels for the 2025 scenario; the penalty being that alternative routes and the option to drive increases overall trip time by 0.4% and may be less convenient than the first-choice route.

  17. Study on Application of T-S Fuzzy Observer in Speed Switching Control of AUVs Driven by States

    Directory of Open Access Journals (Sweden)

    Xun Zhang

    2014-01-01

    Full Text Available Considering the inherent strongly nonlinear and coupling performance of autonomous underwater vehicles (AUVs, the speed switching control method for AUV driven by states is presented. By using T-S fuzzy observer to estimate the states of AUV, the speed control strategies in lever plane, vertical plane, and speed kept are established, respectively. Then the adaptive switching law is introduced to switch the speed control strategies designed in real time. In the simulation, acoustic Doppler current profile/side scan sonar (ADCP/SSS observation case is employed to demonstrate the effectiveness of the proposed method. The results show that the efficiency of AUV was improved, the trajectory tracking error was reduced, and the steady-state ability was enhanced.

  18. Aircraft Oxygen Generation

    Science.gov (United States)

    2012-02-01

    aircraft use some form of on-board oxygen generation provided by one of two corporations that dominate this market . A review of safety incident data...manufacture of synthetic resins (e.g., Bakelite), and for 161 making dyestuffs, flavorings, perfumes , and other chemicals. Some are used as

  19. A High Revolution Speed Noncontact Ultrasonic Motor Driven by a Non-Symmetrical Electrode

    Institute of Scientific and Technical Information of China (English)

    YANG Bin; LIU Jing-Quan; CHEN Di; CAI Bing-Chu

    2005-01-01

    @@ A noncontact ultrasonic motor based on a non-symmetrical electrode is proposed. This motor has the advantages of using a simple driving electrode and having a high revolution speed. The revolution speed of its three-blade rotor can reach 5100rpm under a driving voltage of 20 V. A method operated easily is proposed to measure the output torque.

  20. Aircraft vibration and flutter

    Directory of Open Access Journals (Sweden)

    R. R. Aggarwal

    1958-04-01

    Full Text Available "The paper outlines the theoretical and experimental procedure one has to adopt for flutter prevention during the various stages (project, design and prototype of the development of modern aircraft. With the advent of high speed, the aerodynamic coefficients have to be calculated with due regards to the effects of compressibility, finite aspect ratio of the lifting surfaces, sweep back and other peculiar shapes of the wings. The use of thin, small aspect ratio with external masses, necessitates the computation of higher frequency modes of vibration. Single degree of freedom flutter and the effect of control surface non-linearities has also become very important. Thus, it is shown how the availability of high speed computing machines, improved experimental technique for model and full scale testing has not kept pace with the uncertainties associated with the transonic speeds, low aspect ratio and the high frequency modes. Cross-checking of theoretical and experimental results at every stage seem to be the only answer."

  1. Performance Enhancement of PID Controllers by Modern Optimization Techniques for Speed Control of PMBL DC Motor

    Directory of Open Access Journals (Sweden)

    M. Antony Freeda Rani

    2015-08-01

    Full Text Available Permanent Magnet Brushless DC motor (PMBL DC is used in a large number of industrial and automotive applications because of their high efficiency, compactness and excellent reliability. However to design an efficient PMBL DC motor, it is necessary to provide an effective controller that has to reduce the overshoot, settling and rise time. In this study, an improved PID controller has been designed by optimizing the parameters of PID controller based on two advanced optimization techniques ANFIS and Cuckoo Search optimization for speed control of a PMBL DC motor. The proposed approach has superior features, including easy implementation, stable convergence characteristic and good computational efficiency. The PMBL DC motor is modeled in SIMULINK implementing the algorithms in MATLAB and the performance evaluation has been studied.

  2. Fabrication of TiB2 composite powders coated with BN by high speed airflow impact

    Institute of Scientific and Technical Information of China (English)

    FENG Cai-mei; WANG Wei-min; FU Zheng-yi

    2005-01-01

    TiB2 powders coated with BN were prepared by Hybridization System making use of dry impact blending method to achieve powder surface modification. Parameters of coating were analyzed and the most appropriate condition was summarized. Scan electron microscope of JSM-5610LV and transmission electron microscope of H600STEM/EDS were used to observe the microstructure of coated powders. Results show that treatment time, rotation speed, granularity ratio of TiB2 to BN, pretreatment of materials etc influence the coating results evidently.Mixing raw materials and coating with BN under the appropriate condition can get round TiB2/BN composite powder with smooth surface and compact coating layer.

  3. Adaptable System Increasing the Transmission Speed and Reliability in Packet Network by Optimizing Delay

    Directory of Open Access Journals (Sweden)

    Zbynek Kocur

    2014-01-01

    Full Text Available There is a great diversity in the transmission technologies in current data networks. Individual technologies are in most cases incompatible at physical and partially also at the link layer of the reference ISO/OSI model. Network compatibility, as the ability to transmit data, is realizable through the third layer, which is able to guarantee the operation of the different devices across their technological differences. The proposed inverse packet multiplexer addresses increase of the speed and reliability of packet transmission to the third layer, and at the same time it increases the stability of the data communication by the regulation of the delay value during the transmission. This article presents implementation of a communication system and its verification in real conditions. The conclusion compares the strengths and weaknesses of the proposed control system.

  4. Speed tracking control of PM synchronous motor by internal model design

    Science.gov (United States)

    Ping, Zhaowu; Huang, Jie

    2012-05-01

    In this article, we consider a speed tracking and load torque disturbance rejection problem of PM synchronous motor by internal model design. The problem is first formulated as a global robust output regulation problem of a special class of multivariable systems. Then the output regulation problem is further converted into a global stabilisation problem of an augmented system composed of the original plant and an internal model. As the augmented system does not take any known special form, we have developed a specific tool to deal with the stabilisation problem. In particular, a generalised changing supply function technique applicable to non-input-to-state stable (ISS) systems is developed. This technique, in conjunction with a particular nonlinear internal model, leads to an effective solution to the problem.

  5. Femtosecond probing of light-speed plasma wakefields by using a relativistic electron bunch

    CERN Document Server

    Zhang, C J; Wan, Y; Guo, B; Wu, Y P; Pai, C -H; Li, F; Chu, H -H; Gu, Y Q; Xu, X L; Mori, W B; Joshi, C; Wang, J; Lu, W

    2016-01-01

    Relativistic wakes produced by intense laser or particle beams propagating through plasmas are being considered as accelerators for next generation of colliders and coherent light sources. Such wakes have been shown to accelerate electrons and positrons to several gigaelectronvolts (GeV), with a few percent energy spread and a high wake-to-beam energy transfer efficiency. However, complete mapping of electric field structure of the wakes has proven elusive. Here we show that a high-energy electron bunch can be used to probe the fields of such light-speed wakes with femtosecond resolution. The highly transient, microscopic wakefield is reconstructed from the density modulated ultra-short probe bunch after it has traversed the wake. This technique enables visualization of linear wakefields in low-density plasmas that can accelerate electrons and positrons beams. It also allows characterization of wakes in plasma density ramps critical for maintaining the beam emittance, improving the energy transfer efficiency ...

  6. Nano-strip grating lines self-organized by a high speed scanning CW laser

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Satoru; Ito, Takeshi; Akiyama, Kensuke; Yasui, Manabu; Kato, Chihiro; Tanaka, Satomi; Hirabayashi, Yasuo [Kanagawa Industrial Technology Center, Kanagawa Prefectural Government, 705-1 Shimo-Imaizumi, Ebina, Kanagawa 243-0435 (Japan); Mastuno, Akira; Nire, Takashi [Phoeton Corp., 3050 Okada, Atsugi, Kanagawa 243-0021 (Japan); Funakubo, Hiroshi; Yoshimoto, Mamoru, E-mail: satoru@kanagawa-iri.go.jp [Department of Innovative and Engineered Materials, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502 (Japan)

    2011-04-29

    After a laser annealing experiment on Si wafer, we found an asymmetric sheet resistance on the surface of the wafer. Periodic nano-strip grating lines (nano-SGLs) were self-organized along the trace of one-time scanning of the continuous wave (CW) laser. Depending on laser power, the nano-trench formed with a period ranging from 500 to 800 nm with a flat trough between trench structures. This simple method of combining the scanning laser with high scanning speed of 300 m min{sup -1} promises a large area of nanostructure fabrication with a high output. As a demonstration of the versatile method, concentric circles were drawn on silicon substrate rotated by a personal computer (PC) cooling fan. Even with such a simple system, the nano-SGL showed iridescence from the concentric circles.

  7. Multidisciplinary design optimization of low-noise transport aircraft

    Science.gov (United States)

    Leifsson, Leifur Thor

    The objective of this research is to examine how to design low-noise transport aircraft using Multidisciplinary Design Optimization (MDO). The subject is approached by designing for low-noise both implicitly and explicitly. The explicit design approach involves optimizing an aircraft while explicitly constraining the noise level. An MDO framework capable of optimizing both a cantilever wing and a Strut-Braced-Wing (SBW) aircraft was developed. The objective is to design aircraft for low-airframe-noise at the approach conditions and quantify the change in weight and performance with respect to a traditionally designed aircraft. The results show that reducing airframe noise by reducing approach speed alone, will not provide significant noise reduction without a large performance and weight penalty. Therefore, more dramatic changes to the aircraft design are needed to achieve a significant airframe noise reduction. Another study showed that the trailing-edge flap can be eliminated, as well as all the noise associated with that device, without incurring a significant weight and performance penalty. Lastly, an airframe noise analysis showed that a SBW aircraft with short fuselage-mounted landing gear could have a similar or potentially a lower airframe noise level than a comparable cantilever wing aircraft. The implicit design approach involves selecting a configuration that supports a low-noise operation, and optimizing for performance. In this study a Blended-Wing-Body (BWB) transport aircraft, with a conventional and a distributed propulsion system, was optimized for minimum take-off gross weight. The effects of distributed propulsion were studied using an MDO framework previously developed at Virginia Tech. The results show that more than two thirds of the theoretical savings of distributed propulsion are required for the BWB designs with a distributed propulsion system to have comparable gross weight as those with a conventional propulsion system. Therefore

  8. TRENDS IN THE DEVELOPMENT OF DETONATION ENGINES FOR HIGH-SPEED AEROSPACE AIRCRAFTS AND THE PROBLEM OF TRIPLE CONFIGURATIONS OF SHOCK WAVES. Part II - Research of counterpropagating shock waves and triple shock wave configurations

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2016-03-01

    Full Text Available The paper deals with current issues of the interference theory development of gas-dynamic discontinuities as applied to a problem of propulsion refinement for the air-spacecrafts, designed for hypersonic flight speeds. In the first part of the review we have presented the history of detonation study and different concepts of detonation engines, as well as air intakes designed for hypersonic flight speeds. The second part provides an overview of works on the interference theory development for gas-dynamic discontinuities. We report about classification of the gas-dynamic discontinuities, shock wave propagation, shock-wave structures and triple configurations of shock waves. We have shown that many of these processes are accompanied by a hysteresis phenomenon, there are areas of ambiguity; therefore, in the design of engines and air intakes optimal shock-wave structures should be provided and their sustainability should be ensured. Much attention has recently been given to the use of the air intakes in the shock-wave structures with the rereflection of shock waves and the interference of shock waves in the opposite directions. This review provides increased focus on it, contains references to landmark works, the last calculated and experimental results. Unfortunately, foreign surveys missed many landmark works of the Soviet and Russian researchers, as they were not published in English. At the same time, it was the Soviet school of gas dynamics that has formulated the interference theory of gas-dynamic discontinuities in its present form. To fill this gap is one of this review scopes. The review may be recommended for professionals, engineers and scientists working in the field of aerospace engineering.

  9. Future ultra-speed tube-flight

    Science.gov (United States)

    Salter, Robert M.

    1994-05-01

    Future long-link, ultra-speed, surface transport systems will require electromagnetically (EM) driven and restrained vehicles operating under reduced-atmosphere in very straight tubes. Such tube-flight trains will be safe, energy conservative, pollution-free, and in a protected environment. Hypersonic (and even hyperballistic) speeds are theoretically achievable. Ultimate system choices will represent tradeoffs between amoritized capital costs (ACC) and operating costs. For example, long coasting links might employ aerodynamic lift coupled with EM restraint and drag make-up. Optimized, combined EM lift, and thrust vectors could reduce energy costs but at increased ACC. (Repulsive levitation can produce lift-over-drag l/d ratios a decade greater than aerodynamic), Alternatively, vehicle-emanated, induced-mirror fields in a conducting (aluminum sheet) road bed could reduce ACC but at substantial energy costs. Ultra-speed tube flight will demand fast-acting, high-precision sensors and computerized magnetic shimming. This same control system can maintain a magnetic 'guide way' invariant in inertial space with inertial detectors imbedded in tube structures to sense and correct for earth tremors. Ultra-speed tube flight can complete with aircraft for transit time and can provide even greater passenger convenience by single-model connections with local subways and feeder lines. Although cargo transport generally will not need to be performed at ultra speeds, such speeds may well be desirable for high throughput to optimize channel costs. Thus, a large and expensive pipeline might be replaced with small EM-driven pallets at high speeds.

  10. Study on Impedance Characteristics of Aircraft Cables

    Directory of Open Access Journals (Sweden)

    Weilin Li

    2016-01-01

    Full Text Available Voltage decrease and power loss in distribution lines of aircraft electric power system are harmful to the normal operation of electrical equipment and may even threaten the safety of aircraft. This study investigates how the gap distance (the distance between aircraft cables and aircraft skin and voltage frequency (variable frequency power supply will be adopted for next generation aircraft will affect the impedance of aircraft cables. To be more precise, the forming mechanism of cable resistance and inductance is illustrated in detail and their changing trends with frequency and gap distance are analyzed with the help of electromagnetic theoretical analysis. An aircraft cable simulation model is built with Maxwell 2D and the simulation results are consistent with the conclusions drawn from the theoretical analysis. The changing trends of the four core parameters of interest are analyzed: resistance, inductance, reactance, and impedance. The research results can be used as reference for the applications in Variable Speed Variable Frequency (VSVF aircraft electric power system.

  11. The Role of Aircraft Motion in Airborne Gravity Data Quality

    Science.gov (United States)

    Childers, V. A.; Damiani, T.; Weil, C.; Preaux, S. A.

    2015-12-01

    Many factors contribute to the quality of airborne gravity data measured with LaCoste and Romberg-type sensors, such as the Micro-g LaCoste Turnkey Airborne Gravity System used by the National Geodetic Survey's GRAV-D (Gravity for the Redefinition of the American Vertical Datum) Project. For example, it is well documented that turbulence is a big factor in the overall noise level of the measurement. Turbulence is best controlled by avoidance; thus flights in the GRAV-D Project are only undertaken when the predicted wind speeds at flight level are ≤ 40 kts. Tail winds are known to be particularly problematic. The GRAV-D survey operates on a number of aircraft in a variety of wind conditions and geographic locations, and an obvious conclusion from our work to date is that the aircraft itself plays an enormous role in the quality of the airborne gravity measurement. We have identified a number of features of the various aircraft which can be determined to play a role: the autopilot, the size and speed of the aircraft, inherent motion characteristics of the airframe, tip tanks and other modifications to the airframe to reduce motion, to name the most important. This study evaluates the motion of a number of the GRAV-D aircraft and looks at the correlation between this motion and the noise characteristics of the gravity data. The GRAV-D Project spans 7 years and 42 surveys, so we have a significant body of data for this evaluation. Throughout the project, the sensor suite has included an inertial measurement unit (IMU), first the Applanix POSAv, and then later the Honeywell MicroIRS IMU as a part of a NovAtel SPAN GPS/IMU system. We compare the noise characteristics of the data with measures of aircraft motion (via pitch, roll, and yaw captured by the IMU) using a variety of statistical tools. It is expected that this comparison will support the conclusion that certain aircraft tend to work well with this type of gravity sensor while others tend to be problematic in

  12. Prediction of wind power potential by wind speed probability distribution in a hilly terrain near Bh

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Siraj; Diwakar, Nilesh

    2010-09-15

    Daily wind speed data in metre per second and its direction of flow in degree were recorded from of the India Meteorological Department for a site near the Bhopal Airport for the period of eleven years. The influence of roughness of the terrain, obstacles and topography in terms of contour for the area were also taken into consideration. These data were analysed using WAsP programme and regional wind climate of the area was determined. It is seen from the analysis of the wind speed data and keeping the topographical variation of terrain, exploitable wind speed is experienced at 50 m.

  13. Preparative Separation of Phenolic Compounds from Halimodendron halodendron by High-Speed Counter-Current Chromatography

    Directory of Open Access Journals (Sweden)

    Zhu Yu

    2010-08-01

    Full Text Available Three phenolic compounds, p-hydroxybenzoic acid (1, isorhamnetin-3-O-β-D-rutinoside (2, and 3,3'-di-O-methylquercetin (5, along with a phenolic mixture were successfully separated from the ethyl acetate crude extract of Halimodendron halodendron by high-speed counter-current chromatography (HSCCC with chloroform-methanol-water-acetic acid (4:3:2:0.05, v/v as the two-phase solvent system. The phenolic mixture from HSCCC was further separated by preparative HPLC and purified by Sephadex LH-20 to afford quercetin (3 and 3-O-methylquercetin (4. Seven hundred mg of ethyl acetate crude extract was separated by HSCCC to obtain six fractions which were then analyzed by high performance liquid chromatography (HPLC. The HSCCC separation obtained total of 80 mg of the mixture of quercetin (3 and 3-O-methylquercetin (4 (26.43% and 71.89%, respectively in fraction 2, 14 mg of 3,3'-di-O-methylquercetin (5 at 95.14% of purity in fraction 3, 15 mg of p-hydroxybenzoic acid (1 at 92.83% of purity in fraction 5, 12 mg of isorhamnetin-3-O-β-D-rutinoside (2 at 97.99% of purity in fraction 6. This is the first time these phenolic compounds have been obtained from H. halodendron, and their chemical structures identified by means of physicochemical and spectrometric analysis.

  14. Solidification microstructure of M2 high speed steel by different casting technologies

    Directory of Open Access Journals (Sweden)

    Zhou Xuefeng

    2011-08-01

    Full Text Available The present work investigated the solidification microstructure of AISI M2 high speed steel manufactured by different casting technologies, namely iron mould casting and continuous casting. The results revealed that the as-cast structure of the steel was composed of the iron matrix and the M2C eutectic carbide networks, which were greatly refined in the ingot made by continuous casting process, compared with that by the iron mould casting process. M2C eutectic carbides presented variation in their morphologies and growth characteristics in the ingots by both casting methods. In the ingot by iron mould casting, they have a plate-like morphology and grow anisotropically. However, in the ingot made by continuous casting, the carbides evolved into the fiber-like shape that exhibited little characteristics of anisotropic growth. It was noticed that the fiber-like M2C was much easier to decompose and spheroidize after heated, as a result, the carbides refined remarkably, compared with the case of plate-like carbides in the iron mould casting ingot.

  15. Fractional order PID controller for improvement of PMSM speed control in aerospace applications

    Science.gov (United States)

    Saraji, Ali Motalebi; Ghanbari, Mahmood

    2014-12-01

    Because of the benefits reduced size, cost and maintenance, noise, CO2 emissions and increased control flexibility and precision, to meet these expectations, electrical equipment increasingly utilize in modern aircraft systems and aerospace industry rather than conventional mechanic, hydraulic, and pneumatic power systems. Electric motor drives are capable of converting electrical power to drive actuators, pumps, compressors, and other subsystems at variable speeds. In the past decades, permanent magnet synchronous motor (PMSM) and brushless dc (BLDC) motor were investigated for aerospace applications such as aircraft actuators. In this paper, the fractional-order PID controller is used in the design of speed loop of PMSM speed control system. Having more parameters for tuning fractional order PID controller lead to good performance ratio to integer order. This good performance is shown by comparison fractional order PID controller with the conventional PI and tuned PID controller by Genetic algorithm in MATLAB soft wear.

  16. Fractional order PID controller for improvement of PMSM speed control in aerospace applications

    Energy Technology Data Exchange (ETDEWEB)

    Saraji, Ali Motalebi [Young Researchers and Elite Club, AliAbad Katoul Branch, Islamic Azad University, AliAbad Katoul (Iran, Islamic Republic of); Ghanbari, Mahmood [Department of Electrical Engineering, AliAbad Katoul Branch, Islamic Azad University, AliAbad Katoul (Iran, Islamic Republic of)

    2014-12-10

    Because of the benefits reduced size, cost and maintenance, noise, CO2 emissions and increased control flexibility and precision, to meet these expectations, electrical equipment increasingly utilize in modern aircraft systems and aerospace industry rather than conventional mechanic, hydraulic, and pneumatic power systems. Electric motor drives are capable of converting electrical power to drive actuators, pumps, compressors, and other subsystems at variable speeds. In the past decades, permanent magnet synchronous motor (PMSM) and brushless dc (BLDC) motor were investigated for aerospace applications such as aircraft actuators. In this paper, the fractional-order PID controller is used in the design of speed loop of PMSM speed control system. Having more parameters for tuning fractional order PID controller lead to good performance ratio to integer order. This good performance is shown by comparison fractional order PID controller with the conventional PI and tuned PID controller by Genetic algorithm in MATLAB soft wear.

  17. Numerical Simulation on High-Speed Fragment Impact Against an Aircraft Fuel Tank%高速破片撞击飞机油箱的数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    白强本; 李向东; 贾飞; 杨亚东

    2014-01-01

    In order to evaluate the damage of fuel tanks for aircrafts by hydrodynamic ram (HRAM) event, the damage of characteristics of a water-filled tank facing a fragment impacting are calculated by numerical simulation method of given velocity fragment and the Arbitrary Lagrangian-Eulerian (ALE) technique, the results of tank wall damage are compared with different velocities of fragments and different water filling ratios. The research results show: the damage impacting a full-filed tank is more serious than impacting an empty one, the entry and exit walls relative to the impacted shell have the most serious damage. With the fragment velocity increasing, the deformations on the entry and exit wall are also increasing. The deformation of part-filled tank wall is much smaller than full-filled tank wall. The deformation on 75%filled tank and 85%filled tank is relatively close.%为研究飞机油箱在水锤作用下的破坏效应,运用数值计算方法对高速破片撞击充水箱体的破坏响应进行研究。采用赋予破片速度和ALE建模的方法数值模拟高速破片撞击充水箱体的破坏响应,并对不同破片速度和不同充水比下箱体的变形进行比较分析。计算结果表明:破片撞击充水箱体时的破坏效应较空箱体要严重得多,箱体前后壁的穿孔处周围是发生破坏最严重的区域;箱体前后壁的变形量随破片速度的增加而增加;部分充水箱体的变形明显小于完全充水的情况,但对于充水75%和85%的箱体变形差距不大。

  18. 14 CFR 91.1109 - Aircraft maintenance: Inspection program.

    Science.gov (United States)

    2010-01-01

    ... currently recommended by the manufacturer of the aircraft, aircraft engines, propellers, appliances, and... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Aircraft maintenance: Inspection program... Ownership Operations Program Management § 91.1109 Aircraft maintenance: Inspection program. Each...

  19. 77 FR 42455 - Airworthiness Directives; Piper Aircraft, Inc. Airplanes

    Science.gov (United States)

    2012-07-19

    ... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Piper Aircraft, Inc... directive (AD) for all Piper Aircraft, Inc. (type certificate previously held by The New Piper Aircraft Inc... receive about this proposed AD. Discussion Three forced landings of Piper Aircraft, Inc. Model...

  20. Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

    Science.gov (United States)

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2015-12-08

    A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

  1. Retrofit device to improve vapor compression cooling system performance by dynamic blower speed modulation

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Robert Paul; Hahn, David C.; Scaringe, Robert P.

    2015-12-08

    A device and method are provided to improve performance of a vapor compression system using a retrofittable control board to start up the vapor compression system with the evaporator blower initially set to a high speed. A baseline evaporator operating temperature with the evaporator blower operating at the high speed is recorded, and then the device detects if a predetermined acceptable change in evaporator temperature has occurred. The evaporator blower speed is reduced from the initially set high speed as long as there is only a negligible change in the measured evaporator temperature and therefore a negligible difference in the compressor's power consumption so as to obtain a net increase in the Coefficient of Performance.

  2. Ram speed profile design for isothermal extrusion of AZ31 magnesium alloy by using FEM simulation

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In the conventional hot extrusion of metallic materials,the temperature of the workpiece varies during the whole extrusion process,leading to the non-uniformity of the product dimension,microstructure and properties.In the present research,a simulation model based on the principle of PID control was developed to establish ram speed profiles that can suppress the temperature evolution during the process to allow for isothermaI extrusion.With this simulation model,the real-time extrusion ram speed was adjusted according to the simulated exit temperature.The results show that temperature homogeneity is significantly improved not only along the extrudate length but also on its cross section in the case of extrusion in the isothermal mode with a designed ram speed profile in the extrusion process of AZ31 magnesium.In addition,die temperature varies over a more narrow range in comparison with extrusion in the conventional iso-speed mode.

  3. Pseudophakodonesis and corneal endothelial contact: direct observations by high-speed cinematography.

    Science.gov (United States)

    Jacobs, P M; Cheng, H; Price, N C

    1983-10-01

    High-speed cinematography was used to observe the movement of Federov type I lens implants within the anterior chamber. Our measurements suggest that in most patients contact between the lens implant and corneal endothelium does not occur.

  4. Detection of Aircraft Embedded in Ground Clutter by Means of Non-Doppler X-band Radar

    Science.gov (United States)

    Hwang, Seongin; Ishii, Seishiro; Sayama, Shuji; Sekine, Matsuo

    It is reported that various radar clutter obey a Weibull distribution under certain conditions. To suppress such Weibull-distributed clutter, a new adaptive method was proposed by the present author. In this method, the parameters of the Weibull distribution and the threshold level for an adaptive Constant False Alarm Rate (CFAR) detector are determined by calculating the variance before it passes through a logarithmic amplifier. To apply this new method to practical problems observed by an X-band radar, a computer simulation are made for a finite number of samples in order to obtain the CFAR maintenance in Weibull radar clutter. Finally an improvement value of target-to-clutter ratio 30.07 dB was obtained for the detection of an aircraft embedded in ground clutter.

  5. Smart Materials Technology for High Speed Adaptive Inlet/Nozzle Design Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Enabling a new generation of high speed civil aircraft will require breakthrough developments in propulsion design, including novel techniques to optimize inlet...

  6. High-speed laminar-turbulent boundary layer transition induced by a discrete roughness element

    Science.gov (United States)

    Iyer, Prahladh; Mahesh, Krishnan

    2013-11-01

    Direct numerical simulation (DNS) is used to study laminar to turbulent transition induced by a discrete hemispherical roughness element in a high-speed laminar boundary layer. The simulations are performed under conditions matching the experiments of Danehy et al. (AIAA Paper 2009-394, 2009) for free-stream Mach numbers of 3.37, 5.26 and 8.23. It is observed that the Mach 8.23 flow remains laminar downstream of the roughness, while the lower Mach numbers undergo transition. The Mach 3.37 flow undergoes transition closer to the bump when compared with Mach 5.26, in agreement with experimental observations. Transition is accompanied by an increase in Cf and Ch (Stanton number). Even for the case that did not undergo transition (Mach 8.23), streamwise vortices induced by the roughness cause a significant rise in Cf until 20 D downstream. The mean van Driest transformed velocity and Reynolds stress for Mach 3.37 and 5.26 show good agreement with available data. A local Reynolds number based on the wall properties is seen to correlate with the onset of transition for the cases considered. Partially supported by NASA.

  7. Combined effect of noise and vibration produced by high-speed trains on annoyance in buildings.

    Science.gov (United States)

    Lee, Pyoung Jik; Griffin, Michael J

    2013-04-01

    The effects of noise and vibration on annoyance in buildings during the passage of a nearby high-speed train have been investigated in a laboratory experiment with recorded train noise and 20 Hz vibration. The noises included the effects of two types of façade: windows-open and windows-closed. Subjects were exposed to six levels of noise and six magnitudes of vibration, and asked to rate annoyance using an 11-point numerical scale. The experiment consisted of four sessions: (1) evaluation of noise annoyance in the absence of vibration, (2) evaluation of total annoyance from simultaneous noise and vibration, (3) evaluation of noise annoyance in the presence of vibration, and (4) evaluation of vibration annoyance in the absence of noise. The results show that vibration did not influence ratings of noise annoyance, but that total annoyance caused by combined noise and vibration was considerably greater than the annoyance caused by noise alone. The noise annoyance and the total annoyance caused by combined noise and vibration were associated with subject self-ratings of noise sensitivity. Two classical models of total annoyance due to combined noise sources (maximum of the single source annoyance or the integration of individual annoyance ratings) provided useful predictions of the total annoyance caused by simultaneous noise and vibration.

  8. Detecting single graphene layer by using fluorescence from high-speed Ar^7+ ion

    Science.gov (United States)

    Miyamoto, Yoshiyuki; Zhang, Hong

    2008-03-01

    A highly-charged-ion interacting with graphite causes structural change in nano-scales [1]. While when the ion's kinetic energy reaches few MeVs, the induced is not the structural change but electronic excitation. An experiment [2] showed fluorescence from Ar^7+ ions penetrating through carbon foil with kinetic energy of 2 MeV. Motivated by this experiment, we tested interaction between an Ar^7+ ion and a graphene sheet by the time-dependent density functional approach, and found that the electronic excitation in the Ar^ 7+ ion is also the case even when the incident kinetic energy is 500 KeV and the target thickness is only mono-atomic layer. This simulation suggests the possibility of detecting a suspended mono-atomic layer of graphene [3] by monitoring fluorescence from the penetrated Ar^7+ ions. We will discuss its importance for analyzing bombardment of solids by highly charged, high-speed ions and possible experiments according to the present result. References: [1] T. Meguro, et al., Appl. Phys. Lett 79, 3866 (2001). [2] S. Bashkin, H. Oona, E. Veje, Phys, Rev. A25, 417 (1982). [3] J. Mayer et al., Nature (London), 446, 60 (2007).

  9. Assessment of the suitability of public mobile data networks for aircraft telemetry and control purposes

    Science.gov (United States)

    Gonzalez, F.; Walker, R.; Rutherford, N.; Turner, C.

    2011-04-01

    This paper provides a review of the state of the art of relevant work on the use of public mobile data networks for aircraft telemetry and control proposes. Moreover, it describes the characterisation for airborne uses of the public mobile data communication systems known broadly as 3G. The motivation for this study was to explore how this mature public communication systems could be used for aviation purposes. An experimental system was fitted to a light aircraft to record communication latency, line speed, RF level, packet loss and cell tower identifier. Communications was established using internet protocols and connection was made to a local server. The aircraft was flown in both remote and populous areas at altitudes up to 8500 ft in a region located in South East Queensland, Australia. Results show that the average airborne RF levels are better than those on the ground by 21% and in the order of -77 dbm. Latencies were in the order of 500 ms (1/2 the latency of Iridium), an average download speed of 0.48 Mb/s, average uplink speed of 0.85 Mb/s, a packet of information loss of 6.5%. The maximum communication range was also observed to be 70 km from a single cell station. The paper also describes possible limitations and utility of using such communications architecture for both manned and unmanned aircraft systems.

  10. Aircraft Carriers

    DEFF Research Database (Denmark)

    Nødskov, Kim; Kværnø, Ole

    in Asia and will balance the carrier acquisitions of the United States, the United Kingdom, Russia and India. China’s current military strategy is predominantly defensive, its offensive elements being mainly focused on Taiwan. If China decides to acquire a large carrier with offensive capabilities......, then the country will also acquire the capability to project military power into the region beyond Taiwan, which it does not possess today. In this way, China will have the military capability to permit a change of strategy from the mainly defensive, mainland, Taiwan-based strategy to a more assertive strategy...... catapult with which to launch the fi ghter aircraft, not to mention the possible development of a nuclear power plant for the ship. The Russian press has indicated that China is negotiating to buy SU-33 fi ghters, which Russia uses on the Kuznetsov carrier. The SU-33 is, in its modernized version...

  11. Aircraft recognition and pose estimation

    Science.gov (United States)

    Hmam, Hatem; Kim, Jijoong

    2000-05-01

    This work presents a geometry based vision system for aircraft recognition and pose estimation using single images. Pose estimation improves the tracking performance of guided weapons with imaging seekers, and is useful in estimating target manoeuvres and aim-point selection required in the terminal phase of missile engagements. After edge detection and straight-line extraction, a hierarchy of geometric reasoning algorithms is applied to form line clusters (or groupings) for image interpretation. Assuming a scaled orthographic projection and coplanar wings, lateral symmetry inherent in the airframe provides additional constraints to further reject spurious line clusters. Clusters that accidentally pass all previous tests are checked against the original image and are discarded. Valid line clusters are then used to deduce aircraft viewing angles. By observing that the leading edges of wings of a number of aircraft of interest are within 45 to 65 degrees from the symmetry axis, a bounded range of aircraft viewing angles can be found. This generic property offers the advantage of not requiring the storage of complete aircraft models viewed from all aspects, and can handle aircraft with flexible wings (e.g. F111). Several aircraft images associated with various spectral bands (i.e. visible and infra-red) are finally used to evaluate the system's performance.

  12. Study on Laser Transformation Hardening of HT250 by High Speed Axis Flow CO2 Laser

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this article, laser transformation hardening of HT250 material by high speed axis flow CO2 laser was investigated for first time in China. Appropriate laser hardening parameters, such as laser energy power P(W), laser scanning rate V(m/min),were optimized through a number of experiments. The effect of the mentioned parameters on the hardened zone, including its case depth, microhardness distributions etc., were analyzed. Through the factual experiments, it is proved that axial flow CO2 laser, which commonly outputs low mode laser beam, can also treat materials as long as the treating parameters used are rational. During the experiments, the surface qualities of some specimens treated by some parameters were found to be enhanced, which does not coincide with the former results. Furthermore in the article, the abnormal phenomenon observed in the experiments is discussed. According to the experimental results, the relationship between laser power density q and scanning rate V is shown in a curve and the corresponding formulation, which have been proved to be valuable for choosing the parameters of laser transformation hardening by axial flow CO2 lasers, was also given.

  13. High-speed organocatalytic polymerization of a renewable methylene butyrolactone by a phosphazene superbase

    KAUST Repository

    Schmitt, Meghan L.

    2014-01-01

    The organic phosphazene superbase, 1-tert-butyl-4,4,4-tris(dimethylamino)- 2,2-bis[tris(dimethylamino)phosphoranylid-enamino]-2λ5, 4λ5-catenadi(phosphazene) (t-Bu-P4), is found to directly initiate high-speed polymerization of the biomass-derived renewable γ-methyl-α-methylene-γ-butyrolactone (MMBL), in contrast to other polymerization systems using t-Bu-P4 which typically require addition of an organic acid or a nucleophile as a co-initiating component. This MMBL polymerization by t-Bu-P4 alone is extremely rapid; even with a low t-Bu-P4 loading of 0.1 mol% or 0.02 mol%, quantitative monomer conversion is achieved in 20 s or 1 min, respectively, affording medium to high molecular weight PMMBL bioplastics in a catalytic fashion. The combined experimental and theoretical/computational studies have yielded mechanisms of chain initiation through abstraction of a proton from a monomer by t-Bu-P 4, essentially barrier-less chain propagation through rapid conjugate addition of the enolate anion stabilized by the nano-size cation [t-Bu-P 4H]+ to the monomer, and chain termination through chain transfer to the monomer which generates a saturated termination chain end and the [t-Bu-P4H]+-stabilized anionic active species that starts a new chain. This journal is © the Partner Organisations 2014.

  14. 14 CFR 23.1513 - Minimum control speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 23.1513 Section 23.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Information § 23.1513 Minimum control speed. The minimum control speed V MC, determined under § 23.149,...

  15. 14 CFR 25.1513 - Minimum control speed.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Minimum control speed. 25.1513 Section 25.1513 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Limitations § 25.1513 Minimum control speed. The minimum control speed V MC determined under § 25.149 must...

  16. 14 CFR 23.1511 - Flap extended speed.

    Science.gov (United States)

    2010-01-01

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

  17. Antenna induced hot restrike of a ceramic metal halide lamp recorded by high-speed photography

    Science.gov (United States)

    Hermanns, P.; Hoebing, T.; Bergner, A.; Ruhrmann, C.; Awakowicz, P.; Mentel, J.

    2016-03-01

    The hot restrike is one of the biggest challenges in operating ceramic metal halide lamps with mercury as buffer gas. Compared to a cold lamp, the pressure within a ceramic burner is two orders of magnitude higher during steady state operation due to the high temperature of the ceramic tube and the resulting high mercury vapour pressure. Room temperature conditions are achieved after 300 s of cooling down in a commercial burner, enclosed in an evacuated outer bulb. At the beginning of the cooling down, ignition voltage rises up to more than 14 kV. A significant reduction of the hot-restrike voltage can be achieved by using a so called active antenna. It is realized by a conductive sleeve surrounding the burner at the capillary of the upper electrode. The antenna is connected to the lower electrode of the lamp, so that its potential is extended to the vicinity of the upper electrode. An increased electric field in front of the upper electrode is induced, when an ignition pulse is applied to the lamp electrodes. A symmetrically shaped ignition pulse is applied with an amplitude, which is just sufficient to re-ignite the hot lamp. The re-ignition, 60 s after switching off the lamp, when the mercury pressure starts to be saturated, is recorded for both polarities of the ignition pulse with a high-speed camera, which records four pictures within the symmetrically shaped ignition pulse with exposure times of 100 ns and throws of 100 ns. The pictures show that the high electric field and its temporal variation establish a local dielectric barrier discharge in front of the upper electrode inside the burner, which covers the inner wall of the burner with a surface charge. It forms a starting point of streamers, which may induce the lamp ignition predominantly within the second half cycle of the ignition pulse. It is found out that an active antenna is more effective when the starting point of the surface streamer in front of the sleeve is a negative surface charge on the

  18. Aircraft Electric Secondary Power

    Science.gov (United States)

    1983-01-01

    Technologies resulted to aircraft power systems and aircraft in which all secondary power is supplied electrically are discussed. A high-voltage dc power generating system for fighter aircraft, permanent magnet motors and generators for aircraft, lightweight transformers, and the installation of electric generators on turbine engines are among the topics discussed.

  19. Vibration Control of High-speed Cannonball Transport Mechanism Driven by Impact

    Institute of Scientific and Technical Information of China (English)

    WANG Guo-qing; LIU Hong-zhao; HE Chang-an; YANG Song-feng

    2005-01-01

    A method is presented to control the vibration of high-speed cannonball transport mechanism due to the reduction of its weight, which adhere a nonlinear Zn-27Al-1Cu damping alloy layer and a constraint layer partly to the part of mechanism driven by impact. Based on the equivalent viscous damping theory and using curve fitting to describe the rule of the dissipation factor of damping alloy changing with stress, the nonlinear constitutive relation of Zn-27Al-1Cu damping alloy is given. The nonlinear spring damping contact model is adopted to describe the contact force of the clearance joint.Based on the nonlinear finite element contact theory, the outer impact contact force between the mechanism and its working environment is analyzed, and a coupled dynamic model of structural impact and mechanism motion with clearance joint is put forward. A dynamic model is established for the cannonball transport mechanism partly adhering Zn-27Al-1Cu damping alloy layer and constraint layer under complex impact conditions. At last, the feasibility of the method presented is proved by numerical simulation.

  20. Suppression of broadband noise radiated by a low-speed fan in a duct.

    Science.gov (United States)

    Huang, L; Ma, X; Feng, L G

    2010-07-01

    Attenuation of ducted fan noise remains a technical challenge in the low frequency range as traditional duct lining becomes ineffective. This study proposes a reactive method to suppress the sound radiation from an axial-flow fan. The method is particularly effective in the low frequency region and covers a broad band. Its effect is derived from two mechanisms. One is the reduction in the confining effects of duct walls when the duct radius is increased; the other is the acoustic interference between the direct radiation from the fan and reflections by the duct junctions. This interference is always destructive for axial dipoles when the frequency approaches zero. This performance differs from normal passive control methods, which become totally ineffective toward zero frequency. An approximate plane-wave theory explains the essential physics of the method, and its quantitative prediction is found to agree well with a full numerical simulation using a spectral method of Chebyshev collocation. The latter is validated by experiment using an axial-flow fan in a duct of finite length. Broadband noise reduction is achieved while the flow speed is kept unchanged. Practical difficulties of implementation for a fan with high pressure increase are discussed.

  1. Enhancement of switching speed of BiFeO3 capacitors by magnetic fields

    Directory of Open Access Journals (Sweden)

    E. J. Guo

    2014-09-01

    Full Text Available The effect of a magnetic field on the ferroelectric switching kinetics of BiFeO3 (BFO capacitors with La0.8Ca0.2MnO3 (LCMO bottom electrode and Pt top contact has been investigated. We find a strong dependence of the remnant polarization and coercive field on the magnetic field. The switching time can be systematically tuned by magnetic field and reaches a tenfold reduction around the Curie temperature of LCMO at 4 T. We attribute this behavior to the splitting of the voltage drops across the BFO film and the LCMO bottom electrode, which can be strongly influenced by an external magnetic field due to the magnetoresistance. Further experiments on the BFO capacitors with SrRuO3 bottom electrodes show little magnetic field dependence of ferroelectric switching confirming our interpretation. Our results provide an efficient route to control the ferroelectric switching speed through the magnetic field, implying potential application in multifunctional devices.

  2. Low-speed flowfield characterization by infrared measurements of surface temperatures

    Science.gov (United States)

    Gartenberg, E.; Roberts, A. S., Jr.; Mcree, G. J.

    1989-01-01

    An experimental program was aimed at identifying areas in low speed aerodynamic research where infrared imaging systems can make significant contributions. Implementing a new technique, a long electrically heated wire was placed across a laminar jet. By measuring the temperature distribution along the wire with the IR imaging camera, the flow behavior was identified. Furthermore, using Nusselt number correlations, the velocity distribution could be deduced. The same approach was used to survey wakes behind cylinders in a wind-tunnel. This method is suited to investigate flows with position dependent velocities, e.g., boundary layers, confined flows, jets, wakes, and shear layers. It was found that the IR imaging camera cannot accurately track high gradient temperature fields. A correlation procedure was devised to account for this limitation. Other wind-tunnel experiments included tracking the development of the laminar boundary layer over a warmed flat plate by measuring the chordwise temperature distribution. This technique was applied also to the flow downstream from a rearward facing step. Finally, the IR imaging system was used to study boundary layer behavior over an airfoil at angles of attack from zero up to separation. The results were confirmed with tufts observable both visually and with the IR imaging camera.

  3. Investigating locomotion of dairy cows by use of high speed cinematography.

    Science.gov (United States)

    Herlin, A H; Drevemo, S

    1997-05-01

    The longterm influence of management systems on the locomotion of 17 dairy cows was investigated by high speed cinematography (100 frames/s) and kinematic analysis. Angular patterns and hoof trajectories of the left fore- and hindlimbs are presented and statistics made of occurring minimum and maximum angles. At the recording, 3 cows had been kept in tie-stalls (TI) and 6 cows in cubicles (CI) for a consecutive time of about 2.5 years while 8 cows had been kept on grass for about 3 months. Four of the grazing cows had earlier been kept in cubicles (CG) and 4 in tie-stalls (TG) during earlier off grazing seasons together with TI and CI cows. The CI cows had a smaller maximum angle of the elbow joint compared to TI, TG and CG cows. The hock joint angle of the CI cows was less flexed during the stance phase than in TI and CG cows while the minimum angle during the swing phase was greater in the TI and CI cows compared to TG and CG cows. Pastured cows (TG and CG) had a less pronounced flexion of the fetlock joint angle during the stance compared to cows kept indoors (TI and CI). The results suggest that slatted floor and lack of exercise during summer grazing may affect locomotion. This is indicated by restrictions in the movements of the elbow and hock joints and in less fetlock joint flexion at full support.

  4. Gene synthesis by integrated polymerase chain assembly and PCR amplification using a high-speed thermocycler

    Science.gov (United States)

    TerMaat, Joel R.; Pienaar, Elsje; Whitney, Scott E.; Mamedov, Tarlan G.; Subramanian, Anuradha

    2013-01-01

    Polymerase chain assembly (PCA) is a technique used to synthesize genes ranging from a few hundred base pairs to many kilobase pairs in length. In traditional PCA, equimolar concentrations of single stranded DNA oligonucleotides are repeatedly hybridized and extended by a polymerase enzyme into longer dsDNA constructs, with relatively few full-length sequences being assembled. Thus, traditional PCA is followed by a second primer-mediated PCR reaction to amplify the desired full-length sequence to useful, detectable quantities. Integration of assembly and primer-mediated amplification steps into a single reaction using a high-speed thermocycler is shown to produce similar results. For the integrated technique, the effects of oligo concentration, primer concentration, and number of oligonucleotides are explored. The technique is successfully demonstrated for the synthesis of two genes encoding EPCR-1 (653 bp) and pUC19 β-lactamase (929 bp) in under 20 min. However, rapid integrated PCA–PCR was found to be problematic when attempted with the TM-1 gene (1509 bp). Partial oligonucleotide sets of TM-1 could be assembled and amplified simultaneously, indicating that the technique may be limited to a maximum number of oligonucleotides due to competitive annealing and competition for primers. PMID:19799938

  5. Smoothing Control of Wind Farm Output by Using Kinetic Energy of Variable Speed Wind Power Generators

    Science.gov (United States)

    Sato, Daiki; Saitoh, Hiroumi

    This paper proposes a new control method for reducing fluctuation of power system frequency through smoothing active power output of wind farm. The proposal is based on the modulation of rotaional kinetic energy of variable speed wind power generators through power converters between permanent magnet synchronous generators (PMSG) and transmission lines. In this paper, the proposed control is called Fluctuation Absorption by Flywheel Characteristics control (FAFC). The FAFC can be easily implemented by adding wind farm output signal to Maximum Power Point Tracking control signal through a feedback control loop. In order to verify the effectiveness of the FAFC control, a simulation study was carried out. In the study, it was assumed that the wind farm consisting of PMSG type wind power generator and induction machine type wind power generaotors is connected with a power sysem. The results of the study show that the FAFC control is a useful method for reducing the impacts of wind farm output fluctuation on system frequency without additional devices such as secondary battery.

  6. Flight Dynamic Modeling and Analysis for a Low speed Multimode Aircraft%一种低速复合升力飞行器飞行动力学建模与分析

    Institute of Scientific and Technical Information of China (English)

    刘凯; 高正红; 黄晶

    2014-01-01

    Considering the characteristic of a multimode aircraft which consists of a ducted fan and two tilt propellers,the flight dynamic model was developed and analyzed.The momentum theo-ry was used to build the flight dynamic model for the ducted fan.Considering the redundant prob-lems in manipulating the multimode aircraft,a rea-sonable manipulation strategy was calculated.The linear models were obtained and the longitude dy-namical stability for typical flight states were ana-lyzed in different flight models.The results show that the model contains the typical characteristic of the multimode aircraft.%针对一种由升力风扇和倾转螺旋桨组成的复合升力飞行器构型特点,建立其飞行动力学模型并进行分析研究。应用动量理论分析了升力风扇的气动力。建立了飞行器纵向动力学模型。针对飞行器飞行模式转换阶段特存的操纵冗余问题,提出了合理的配平策略,完成平衡计算。在平衡状态点线化模型,并对不同飞行模式下典型飞行状态纵向动稳定性进行分析。结果表明,系统所建立的模型能够反映该类符合升力飞行器各飞行模式的典型特征。

  7. D-558-2 being mounted to P2B-1S launch aircraft

    Science.gov (United States)

    1953-01-01

    aircraft gathered a great deal of data about pitch-up and the coupling of lateral (yaw) and longitudinal (pitch) motions; wing and tail loads, lift, drag, and buffeting characteristics of swept-wing aircraft at transonic and supersonic speeds; and the effects of the rocket exhaust plume on lateral dynamic stability throughout the speed range. (Plume effects were a new experience for aircraft.) The number three aircraft also gathered information about the effects of external stores (bomb shapes, drop tanks) upon the aircraft's behavior in the transonic region (roughly 0.7 to 1.3 times the speed of sound). In correlation with data from other early transonic research aircraft such as the XF-92A, this information contributed to solutions to the pitch-up problem in swept-wing aircraft. The three airplanes flew a total of 313 times--123 by the number one aircraft (Bureau No. 37973--NACA 143), 103 by the second Skyrocket (Bureau No. 37974--NACA 144), and 87 by airplane number three (Bureau No. 37975--NACA 145). Skyrocket 143 flew all but one of its missions as part of the Douglas contractor program to test the airplane's performance. NACA aircraft 143 was initially powered by a Westinghouse J-34-40 turbojet engine configured only for ground take-offs, but in 1954-55 the contractor modified it to an all-rocket air-launch capability featuring an LR8-RM-6, 4-chamber Reaction Motors engine rated at 6,000 pounds of thrust at sea level (the Navy designation for the Air Force's LR-11 used in the X-1). In this configuration, NACA research pilot John McKay flew the airplane only once for familiarization on September 17, 1956. The 123 flights of NACA 143 served to validate wind-tunnel predictions of the airplane's performance, except for the fact that the airplane experienced less drag above Mach 0.85 than the wind tunnels had indicated. NACA 144 also began its flight program with a turbojet powerplant. NACA pilots Robert A. Champine and John H. Griffith flew 21 times in this configuration

  8. Aircraft Lightning Electromagnetic Environment Measurement

    Science.gov (United States)

    Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.

    2011-01-01

    This paper outlines a NASA project plan for demonstrating a prototype lightning strike measurement system that is suitable for installation onto research aircraft that already operate in thunderstorms. This work builds upon past data from the NASA F106, FAA CV-580, and Transall C-180 flight projects, SAE ARP5412, and the European ILDAS Program. The primary focus is to capture airframe current waveforms during attachment, but may also consider pre and post-attachment current, electric field, and radiated field phenomena. New sensor technologies are being developed for this system, including a fiber-optic Faraday polarization sensor that measures lightning current waveforms from DC to over several Megahertz, and has dynamic range covering hundreds-of-volts to tens-of-thousands-of-volts. A study of the electromagnetic emission spectrum of lightning (including radio wave, microwave, optical, X-Rays and Gamma-Rays), and a compilation of aircraft transfer-function data (including composite aircraft) are included, to aid in the development of other new lightning environment sensors, their placement on-board research aircraft, and triggering of the onboard instrumentation system. The instrumentation system will leverage recent advances in high-speed, high dynamic range, deep memory data acquisition equipment, and fiber-optic interconnect.

  9. Dechlorination of pentachlorophenol by grinding at low rotation speed in short time

    Institute of Scientific and Technical Information of China (English)

    Zhi Xu; Xiaoyu Zhang; Qingzhi Fei

    2015-01-01

    In order to apply grinding method for degradation of pentachlorophenol (PCP) to an industrial scale, the propor-tion of different materials [CaO, SiO2 and CO(NH2)2] and the size of grinding balls were examined. For saving en-ergy and increasing dechlorination efficiency, the rotation speed and grinding time were maintained at relatively low values. At a mass ratio of grinding bal s to materials (40:1), PCP was added into a big steel jar (300 ml) with other materials to grind at 300 r·min−1 for 5 h. The results indicated that when PCP was mixed with CaO and SiO2 in a molar ratio of 1:60:60, the best dechlorination of 58.4%was achieved. CO(NH2)2 could not be used as hydro-gen donor in the dehalogenation by mechanochemical reaction, since it restrained the dechlorination process. The size of grinding balls has significant effect on the reaction. The experiment with 5 mm steel balls indicates that the weight is too light to provide appropriate energy for the reaction, while steel balls of 10 and 15 mm could give better dechlorination reaction. It indicates that dechlorination depends on the mass of balls and fill rate.

  10. Sliding mode direct power control of RSC for DFIGs driven by variable speed wind turbines

    Directory of Open Access Journals (Sweden)

    E.G. Shehata

    2015-12-01

    Full Text Available In spite of its several advantages, a classic direct power control (DPC of doubly fed induction generators (DFIGs driven by variable speed wind turbines has some drawbacks. In this paper, a simple and robust total sliding mode controller (TSMC is designed to improve the classical DPC performance without complicating the overall scheme. The TSMC is designed to regulate the DFIG stator active and reactive powers. Two integral switching functions are selected for describing the switching surfaces of the active and reactive powers. Reaching phase stability problem of the classical sliding mode controller is avoided in the proposed TSMC. Neither current control loops nor accurate values of machine parameters are required in the proposed scheme. In addition, axes transformation of the stator voltage and current are eliminated. The grid side converter is controlled based on DPC principle to regulate both DC-link voltage and total reactive power. The feasibility of the proposed DPC scheme is validated through simulation studies on a 1.5 MW wind power generation system. The performance of the proposed and conventional DPC schemes is compared under different operating conditions.

  11. Microstructure simulation of rapidly solidified ASP30 high-speed steel particles by gas atomization

    Science.gov (United States)

    Ma, Jie; Wang, Bo; Yang, Zhi-liang; Wu, Guang-xin; Zhang, Jie-yu; Zhao, Shun-li

    2016-03-01

    In this study, the microstructure evolution of rapidly solidified ASP30 high-speed steel particles was predicted using a simulation method based on the cellular automaton-finite element (CAFE) model. The dendritic growth kinetics, in view of the characteristics of ASP30 steel, were calculated and combined with macro heat transfer calculations by user-defined functions (UDFs) to simulate the microstructure of gas-atomized particles. The relationship among particle diameter, undercooling, and the convection heat transfer coefficient was also investigated to provide cooling conditions for simulations. The simulated results indicated that a columnar grain microstructure was observed in small particles, whereas an equiaxed microstructure was observed in large particles. In addition, the morphologies and microstructures of gas-atomized ASP30 steel particles were also investigated experimentally using scanning electron microscopy (SEM). The experimental results showed that four major types of microstructures were formed: dendritic, equiaxed, mixed, and multi-droplet microstructures. The simulated results and the available experimental data are in good agreement.

  12. A New Distributed Measurement of Birefringence Vectors by P-OTDR Assisted by a High Speed Polarization Analyzer

    Institute of Scientific and Technical Information of China (English)

    SHANG Chao; WU Chong-Qing; LI Zheng-Yong; YANG Shuang-Show

    2011-01-01

    A new polarimetric optical time domain reflectometry (P-OTDR) measurement device assisted by a high speed polarization analyzer is designed and a new algorithm, which can be used to accurately measure the birefringence vector, is proposed. In this method, only one measurement is required and the result is insensitive to the input state of polarization. An 1-km single mode fiber (SMF) is measured and the distribution of the local birefringence vector along the SMF is obtained with a resolution of 2 cm.%@@ A new polarimetric optical time domain reflectometry(P-OTDR)measurement device assisted by a high speed polarization analyzer is designed and a new algorithm,which can be used to accurately measure the birefringence vector,is proposed.In this method,only one measurement is required and the result is insensitive to the input state of polarization.An 1-km single mode fiber(SMF)is measured and the distribution of the local birefringence vector along the SMF is obtained with a resolution of 2 cm.

  13. Conceptual design and optimization methodology for box wing aircraft

    OpenAIRE

    Jemitola, Paul Olugbeji

    2012-01-01

    A conceptual design optimization methodology was developed for a medium range box wing aircraft. A baseline conventional cantilever wing aircraft designed for the same mis- sion and payload was also optimized alongside a baseline box wing aircraft. An empirical formula for the mass estimation of the fore and aft wings of the box wing aircraft was derived by relating conventional cantilever wings to box wing aircraft wings. The results indicate that the fore and aft wings would ...

  14. Improvement of power system stability by high speed power control of adjustable speed machine; Kahensokuki no koshutsuryoku seigyo ni yoru denryoku keito no anteido kojo

    Energy Technology Data Exchange (ETDEWEB)

    Nojiri, K.; Kikuchi, T.; Nakagawa, H. [Kansai Electric Power Co. Inc., Osaka (Japan); Goto, M. [Hitachi, Ltd., Tokyo (Japan); Nohara, H. [Hitachi Nuclear Engineering Co. Ltd., Tokyo (Japan)

    1997-01-20

    Large capacity adjustable speed machines (ASMs) at pumped storage power station have been put into full operation and the operating characteristics of ASM have been highly evaluated from the view point of power system operation. The output power (input power) of ASM can be controlled very quickly by applying a vector control scheme to the excitation control. This quick responsive feature of ASM can make it possible to improve the stability of the neighbor sub-power system. For improvement of transient stability, the output power of ASM is reduced very quickly in order to control the acceleration of neighbor generators during and after transmission line faults. For improvement of dynamic stability, the output power of ASM is modulated in accordance with the stabilizing signals detected from the swing of generator rotor or the power flow fluctuation on the transmission line. This paper describes the design concepts and method of control system for improving the transient and dynamic stability and proposes a power system stabilizing control system. The effects of the proposed stabilizing control system have been verified by a power system simulator. 9 refs., 15 figs., 1 tab.

  15. High speed data acquisition and processing system for flight test data of aircraft power system%飞机电源系统飞行试验数据高速采集及处理系统设计与实现

    Institute of Scientific and Technical Information of China (English)

    陈艳; 李太平; 陈永碌

    2016-01-01

    In this paper, the need for aircraft electric power characteristics evaluation of design a will power system flight test data real-time and high-speed acquisition, solution, and continuous recording of data processing system, guarantee based on the accuracy and completeness of the flight test data recording, easing the pressure of large data records, improve the efficiency of test data processing to meet the needs assessment for the aircraft power supply system.%本文针对飞机供电特性考核的需要,设计了一套将电源系统飞行试验数据实时高速采集、解算,并连续记录的数据处理系统,在保证飞行试验数据记录的准确性和完整性的基础上,缓解了大数据记录的压力,提高了试验数据处理的效率,满足了对飞机电源系统评估的需求。

  16. Aerodynamic performance of 0.5 meter-diameter, 337 meter-per-second tip speed, 1.5 pressure-ratio, single-stage fan designed for low noise aircraft engines

    Science.gov (United States)

    Gelder, T. F.; Lewis, G. W., Jr.

    1974-01-01

    Overall and blade-element aerodynamic performance of a 0.271-scale model of QF-1 are presented, examined, and then compared and evaluated with that from similar low noise fan stage designs. The tests cover a wide range of speeds and weight flows along with variations in stator setting angle and stator axial spacing from the rotor. At design speed with stator at design setting angle and a fixed distance between stage measuring stations, there were no significant effects of increasing the axial spacing between rotor stator from 1.0 to 3.5 rotor chords on stage overall pressure ratio, efficiency or stall margin.

  17. Static and Dynamic Characteristic Simulation of Feed System Driven by Linear Motor in High Speed Computer Numerical Control Lathe

    Directory of Open Access Journals (Sweden)

    Yang Zeqing

    2013-07-01

    Full Text Available In order to design the feed system of high speed Computer Numerical Control (CNC lathe, the static and dynamic characteristics of feed system driven by linear motor in high speed CNC lathe were analyzed. The slide board was taking as the main moving part of the feed system, and the guide rail was the main support component of the linear motor feed system. The mechanical structure static stiffness of feed system is researched through the slide board statics analysis. The simulation results show that the maximum deformation of the slide board occurs in the middle of the slide board where the linear motor is placed. The linear motor feed system control model was established based on analysis of high-speed linear feed system control principle, and the linear motor feed system transfer function was established, and servo dynamic stiffness factors were analyzed. The control parameters of the servo system and actuating mechanism parameters of feed system on the effect of the linear motor servo dynamic stiffness were analyzed using MATLAB software. The simulation results show that the position loop proportional gain, speed loop proportional gain and speed loop integral response time are the biggest influence factors on servo dynamic stiffness. The displacement response is reduced under the cutting interference force step inputting, the servo dynamic stiffness is increased, the number of system oscillation is also reduced, and the system tends to be stable.  

  18. Developing aircraft photonic networks for airplane systems

    DEFF Research Database (Denmark)

    White, Henry J.; Brownjohn, Nick; Baptista, João;

    2013-01-01

    Achieving affordable high speed fiber optic communication networks for airplane systems has proved to be challenging. In this paper we describe a summary of the EU Framework 7 project DAPHNE (Developing Aircraft Photonic Networks). DAPHNE aimed to exploit photonic technology from terrestrial comm...

  19. MICROSTRUCTURING OF SILICON SINGLE CRYSTALS BY FIBER LASER IN HIGH-SPEED SCANNING MODE

    Directory of Open Access Journals (Sweden)

    T. A. Trifonova

    2015-11-01

    Full Text Available Subject of Study. The surface structure of the silicon wafers (substrate with a thermally grown silicon dioxide on the surface (of SiO2/Si is studied after irradiation by pulse fiber laser of ILI-1-20 type. The main requirements for exposure modes of the system are: the preservation of the integrity of the film of silicon dioxide in the process of microstructuring and the absence of interference of surrounding irradiated areas of the substrate. Method. Studies were carried out on silicon wafers KEF-4,5 oriented in the crystallographic plane (111 with the source (natural silicon dioxide (SiO2 with thickness of about 4 nm, and SiO2 with 40 nm and 150 nm thickness, grown by thermal oxidation in moist oxygen. Also, wafers KHB-10 oriented in the plane (100 with 500 nm thickness of thermal oxide were investigated. Irradiation of SiO2/Si system was produced by laser complex based on ytterbium fiber pulse laser ILI-1-20. Nominal output power of the laser was 20 W, and the laser wavelength was λ = 1062 nm. Irradiation was carried out by a focused beam spot with a diameter of 25 microns and a pulse repetition rate of 99 kHz. The samples with 150 nm and 40 nm thickness of SiO2 were irradiated at a power density equal to 1,2·102 W/cm2, and the samples of SiO2 with 500 nm thickness were irradiated at a power density equal to 2,0·102 W/cm2. Scanning was performed using a two-axis Coordinate Scanning Device based on VM2500+ drives with control via a PC with the software package "SinMarkTM." Only one scan line was used at the maximum speed of the beam equal to 8750 mm/s. Morphology control of the irradiated samples was conducted by an optical microscope ZeissA1M with high-resolution CCD array. A scanning probe microscope Nanoedicator of the NT-MDT company was used for structural measurements. Main Results. It has been shown that at a single exposure of high-frequency pulsed laser radiation on SiO2/Si system, with maintaining the integrity of the SiO2 film

  20. The generation of gravity-capillary solitary waves by a pressure source moving at a trans-critical speed

    Science.gov (United States)

    Masnadi, Naeem; Duncan, James H.

    2017-01-01

    The unsteady response of a water free surface to a localized pressure source moving at constant speed $U$ in the range $0.95c_\\mathrm{min} \\lesssim U \\leq 1.02 c_\\mathrm{min}$, where $c_\\mathrm{min}$ is the minimum phase speed of linear gravity-capillary waves in deep water, is investigated through experiments and numerical simulations. This unsteady response state, which consists of a V-shaped pattern behind the source and features periodic shedding of pairs of depressions from the tips of the V, was first observed qualitatively by Diorio et al. (Phys. Rev. Let., 103, 214502, 2009) and called state III. In the present investigation, cinematic shadowgraph and refraction-based techniques are utilized to measure the temporal evolution of the free surface deformation pattern downstream of the source as it moves along a towing tank, while numerical simulations of the model equation described by Cho et al. (J. Fluid Mech., 672, 288-306, 2011) are used to extend the experimental results over longer times than are possible in the experiments. From the experiments, it is found that the speed-amplitude characteristics and the shape of the depressions are nearly the same as those of the freely propagating gravity-capillary lumps of inviscid potential theory. The decay rate of the depressions is measured from their height-time characteristics, which are well fitted by an exponential decay law with an order 1 decay constant. It is found that the shedding period of the depression pairs decreases with increasing source strength and speed. As the source speed approaches $c_\\mathrm{min}$, this period tends to about 1~s for all source magnitudes. At the low-speed boundary of state III, a new response with unsteady asymmetric shedding of depressions is found. This response is also predicted by the model equation.

  1. A simulation study of the low-speed characteristics of a light twin with an engine-out

    Science.gov (United States)

    Stewart, E. C.; Moul, T. M.; Brown, P. W.

    1983-01-01

    Potential safety advantages provided by the two engines on a light twin aircraft are not realized in practice as evidenced by recent engine-failure accident statistics. These statistics showed twice the fatality rate from engine failure for twins as for single-engine aircraft. The statistics showed also that one-half of the fatal engine-out accidents involved a stall. An improvement of the low-speed engine-out characteristics is, therefore, needed. An investigation of the engine-out characteristics of light twin-engine aircraft is currently being conducted as part of the comprehensive stall/spin program for general aviation aircraft. The present study is concerned with the first phase of this program. The primary objective of this study is to advance the understanding of the basic flight dynamics and piloting problems for an engine-out condition. An all-digital computer system was used in the conducted simulation study.

  2. 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

  3. Development of an efficient soymilk cream production method by papain digestion, heat treatment, and low-speed centrifugation.

    Science.gov (United States)

    Abe, Naoki; Wu, Chang-Yu; Kim, Yoon-Kyung; Fujii, Tomoyuki; Abe, Keietsu

    2015-01-01

    We developed the simple method of soymilk cream production from the high-fat soymilk, which was prepared by papain digestion and heat treatment. As a result of the treatment, high-fat soymilk was aggregated and it became possible to separate soymilk cream as the surface fraction by low-speed centrifugation (6000 × g, 10 min).

  4. Causes of aircraft electrical failures

    Science.gov (United States)

    Galler, Donald; Slenski, George

    1991-08-01

    The results of a survey of data on failures of aircraft electronic and electrical components that was conducted to identify problematic components are reported. The motivation for the work was to determine priorities for future work on the development of accident investigation techniques for aircraft electrical components. The primary source of data was the Airforce Mishap Database, which is maintained by the Directorate of Aerospace Safety at Norton Air Force Base. Published data from the Air Force Avionics Integrity Program (AVIP) and Hughes Aircraft were also reviewed. Statistical data from these three sources are presented. Two major conclusions are that problems with interconnections are major contributors to aircraft electrical equipment failures, and that environmental factors, especially corrosion, are significant contributors to connector problems.

  5. Aircraft recognition and tracking device

    Science.gov (United States)

    Filis, Dimitrios P.; Renios, Christos I.

    2011-11-01

    The technology of aircraft recognition and tracking has various applications in all areas of air navigation, be they civil or military, spanning from air traffic control and regulation at civilian airports to anti-aircraft weapon handling and guidance for military purposes.1, 18 The system presented in this thesis is an alternative implementation of identifying and tracking flying objects, which benefits from the optical spectrum by using an optical camera built into a servo motor (pan-tilt unit). More specifically, through the purpose-developed software, when a target (aircraft) enters the field of view of the camera18, it is both detected and identified.5, 22 Then the servo motor, being provided with data on target position and velocity, tracks the aircraft while it is in constant communication with the camera (Fig. 1). All the features are so designed as to operate under real time conditions.

  6. Twenty-four hour predictions of the solar wind speed peaks by the probability distribution function model

    Science.gov (United States)

    Bussy-Virat, C. D.; Ridley, A. J.

    2016-10-01

    Abrupt transitions from slow to fast solar wind represent a concern for the space weather forecasting community. They may cause geomagnetic storms that can eventually affect systems in orbit and on the ground. Therefore, the probability distribution function (PDF) model was improved to predict enhancements in the solar wind speed. New probability distribution functions allow for the prediction of the peak amplitude and the time to the peak while providing an interval of uncertainty on the prediction. It was found that 60% of the positive predictions were correct, while 91% of the negative predictions were correct, and 20% to 33% of the peaks in the speed were found by the model. This represents a considerable improvement upon the first version of the PDF model. A direct comparison with the Wang-Sheeley-Arge model shows that the PDF model is quite similar, except that it leads to fewer false positive predictions and misses fewer events, especially when the peak reaches very high speeds.

  7. Detailed stability investigation of amorphous solid dispersions prepared by single-needle and high speed electrospinning.

    Science.gov (United States)

    Démuth, B; Farkas, A; Pataki, H; Balogh, A; Szabó, B; Borbás, E; Sóti, P L; Vigh, T; Kiserdei, É; Farkas, B; Mensch, J; Verreck, G; Van Assche, I; Marosi, G; Nagy, Z K

    2016-02-10

    In this research the long-term stability (one year) of amorphous solid dispersions (ASDs) prepared by high speed electrospinning was investigated at 25 °C/60% relative humidity (RH) (closed conditions) and 40 °C/75% RH (open conditions). Single needle electrospinning and film casting were applied as reference technologies. Itraconazole (ITR) was used as the model API in 40% concentration and the ASDs consisted of either one of the following polymers as a comparison: polyvinylpyrrolidone-vinyl acetate 6:4 copolymer (no hydrogen bonds between API and polymer) and hydroxypropyl methylcellulose (possible hydrogen bonds between oxo or tertiary nitrogen function of API and hydroxyl moiety of polymer). DSC, XRPD and dissolution characteristics of samples at 0, 3 and 12 months were investigated. In addition, Raman maps of certain electrospun ASDs were assessed to investigate crystallinity. A new chemometric method, based on Multivariate Curve Resolution-Alternating Least Squares algorithm, was developed to calculate the spectrum of amorphous ITR in the matrices and to determine the crystalline/amorphous ratio of aged samples. As it was expected ITR in single needle electrospun SDs was totally amorphous at the beginning, in addition hydroxypropyl methylcellulose could keep ITR in this form at 40 °C/75% RH up to one year due to the hydrogen bonds and high glass transition temperature of the SD. In polyvinylpyrrolidone-vinyl acetate matrix ITR remained amorphous at 25 °C/60% RH throughout one year. Materials prepared by scaled-up, high throughput version of electrospinning, which is compatible with pharmaceutical industry, also gained the same quality. Therefore these ASDs are industrially applicable and with an appropriate downstream process it would be possible to bring them to the market.

  8. Aircraft Data Acquisition

    OpenAIRE

    Elena BALMUS

    2016-01-01

    The introduction of digital systems instead of analog ones has created a major separation in the aviation technology. Although the digital equipment made possible that the increasingly faster controllers take over, we should say that the real world remains essentially analogue [4]. Fly-by-wire designers attempting to control and measure the real feedback of an aircraft were forced to find a way to connect the analogue environment to their digital equipment. In order to manage the implications...

  9. Slotted Aircraft Wing

    Science.gov (United States)

    McLean, James D. (Inventor); Witkowski, David P. (Inventor); Campbell, Richard L. (Inventor)

    2006-01-01

    A swept aircraft wing includes a leading airfoil element and a trailing airfoil element. At least one full-span slot is defined by the wing during at least one transonic condition of the wing. The full-span slot allows a portion of the air flowing along the lower surface of the leading airfoil element to split and flow over the upper surface of the trailing airfoil element so as to achieve a performance improvement in the transonic condition.

  10. Method and Device for Speed Change by the Epicyclic Gear Train with Stepped-Planet Gear Set

    Directory of Open Access Journals (Sweden)

    Malashchenko Volodymyr

    2016-08-01

    Full Text Available The article describes new method and device for continuously variable speed change management via compound epicyclic gearing with composite planet gears and closed circuit hydrosystem, when the speed control element is either outer ring gear (annulus or the carrier or sun gear. In each case, the control element connected to closed circuit hydrosystem and can be in motion or immovable depending on the bandwidth of hydrosystem’s regulating throttle. We had held theoretical research and received graphic dependences between velocities of driving, control and driven elements by means of computer programing.

  11. Error Analysis of Ship Speed Measurement by GPS%舰船 GPS 测速误差分析

    Institute of Scientific and Technical Information of China (English)

    张凯

    2014-01-01

    This paper discusses the fundamental principle of GPS speed measurement and the actual sailing of naval vessel, works out the reason of the ship speed measurement by using GPS with theoretical analyses, and puts forward the solution.%本文论述了GPS测速的基本原理与舰船在海中的实际航行情况,通过理论分析得出了利用GPS对舰船进行航速测量的原因,并提出了解决方案。

  12. Synoptic tracer gradients in the upper troposphere over central Canada during the Stratosphere-Troposphere Experiments by Aircraft Measurements 1998 summer campaign

    NARCIS (Netherlands)

    Fischer, H.; Brunner, D; Harris, GW; Hoor, P; Lelieveld, J; McKenna, DS; Rudolph, J; Scheeren, HA; Siegmund, P; Wernli, H; Williams, J; Wong, S

    2002-01-01

    [1] During the July 1998 Stratosphere-Troposphere Experiments by Aircraft Measurements (STREAM) intensive campaign, eight measurement flights were conducted from Timmins airport (Ontario, Canada, 48.2degreesN, 79.3degreesW). In situ measurements of ozone, carbon monoxide, carbon dioxide, and nonmeth

  13. Stabilisation of Parametric Roll Resonance by Combined Speed and Fin Stabiliser Control

    DEFF Research Database (Denmark)

    Galeazzi, Roberto; Holden, Christian; Blanke, Mogens;

    2009-01-01

    of the nonlinear system and suggests active control of both ship speed and fin stabilizers to stabilise the roll resonance condition. Lyapunov and backstepping designs are employed to achieve two nonlinear controllers, which are proved to stabilise the nonlinear system. The designed controllers are validated...

  14. Minimum Wave Speed Solution of Fisher's Equation by the Method of Least Squares - A Note

    Directory of Open Access Journals (Sweden)

    K. N. Mehta

    1989-04-01

    Full Text Available The paper presents a simple solution of travelling-wave type (corresponding to the minimum speed c=2 of Fisher's equation. which can be readily adapted for modelling neutron density in nuclear reactors, reaction-diffusion processes'in propulsion systems and growth of new advantageous gene in one-dimensional habitat

  15. Experimenting from a Distance--Determination of Speed of Light by a Remotely Controlled Laboratory (RCL)

    Science.gov (United States)

    Grober, S.; Vetter, M.; Eckert, B.; Jodl, H.-J.

    2010-01-01

    The speed of light is an essential topic in the teaching of physics at school and at university, either with respect to the type of experiment or of course with respect to its genuine inherent importance. In reality, the various available experiments are hardly ever performed in class for many reasons. Therefore, we offer this experiment as a…

  16. Optimised Cockpit Heat Load Analysis using Skin Temperature Predicted by CFD and Validation by Thermal Mapping to Improve the Performance of Fighter Aircraft

    Directory of Open Access Journals (Sweden)

    Paresh Gupta

    2015-03-01

    Full Text Available Designing of optimum environmental control system (ECS plays a major role for increasing performance of fighter aircraft depending upon requirement of engine bleed air for running of ECS. Accurate estimation of cockpit skin temperature for obtaining optimised cockpit heat load helps in estimation of engine bleed air for ECS. Present research evolved a methodology for comparing the theoretically calculated skin temperature with computational fluid dynamics (CFD analysis to obtain optimum skin temperature. Results are validated by flight tests under critical flight conditions using thermal crayons. Based on which the optimized heat load and bleed air requirements has been computed. Uncertainty analysis of skin temperature measurement for thermal crayons have been undertaken. The results indicate that the theoretical skin temperature is -26.70 per cent as that of CFD estimated skin temperature. Optimized average cockpit heat load at critical flight profiles is 0.74 times the theoretical cockpit heat load, leading to reduction of bleed air requirement by 26 per cent as compared to theoretical. Due to this literature survey has pridicted the increase in performance parameters like increase in bleed air pressure by 78 per cent, increase in thrust by 60 per cent, and decrease in specific fuel consumption (SFC by 40 per cent to improve the endurance of aircraft. The research has generated governing equations for variation of cockpit heat loads w.r.t aircraft skin temperatures.Defence Science Journal, Vol. 65, No. 1, January 2015, pp.12-24, DOI:http://dx.doi.org/10.14429/dsj.65.7200

  17. Aircraft noise in the region of the Bucharest-Otopeni Airport. [noise pollution in airport environment

    Science.gov (United States)

    Costescu, M.; Gherghel, C.; Curtoglu, A.

    1974-01-01

    Aircraft noise, especially in the region adjoining airports, constitutes a problem that will be aggravated in the near future because of increasing aircraft traffic and the appearance of new types of large tonnage aircraft with continuously increasing powers and speeds. Criteria for the evaluation of aircraft noise are reported and some results of studies carried out in the region of Bucharest-Otopeni Airport are detailed.

  18. Mapping automotive like controls to a general aviation aircraft

    Science.gov (United States)

    Carvalho, Christopher G.

    The purpose of this thesis was to develop fly-by-wire control laws enabling a general aviation aircraft to be flown with automotive controls, i.e. a steering wheel and gas/brake pedals. There was a six speed shifter used to change the flight mode of the aircraft. This essentially allows the pilot to have control over different aspects of the flight profile such as climb/descend or cruise. A highway in the sky was used to aid in the navigation since it is not intuitive to people without flight experience how to navigate from the sky or when to climb and descend. Many believe that general aviation could become as widespread as the automobile. Every person could have a personal aircraft at their disposal and it would be as easy to operate as driving an automobile. The goal of this thesis is to fuse the ease of drivability of a car with flight of a small general aviation aircraft. A standard automotive control hardware setup coupled with variably autonomous control laws will allow new pilots to fly a plane as easily as driving a car. The idea is that new pilots will require very little training to become proficient with these controls. Pilots with little time to stay current can maintain their skills simply by driving a car which is typically a daily activity. A human factors study was conducted to determine the feasibility of the applied control techniques. Pilot performance metrics were developed to compare candidates with no aviation background and experienced pilots. After analyzing the relative performance between pilots and non-pilots, it has been determined that the control system is robust and easy to learn. Candidates with no aviation experience whatsoever can learn to fly an aircraft as safely and efficiently as someone with hundreds of hours of flight experience using these controls.

  19. High-Speed Analyzing PCR Products of M. tuberculosis Genome Stained by Ethidium Bromide on Microchip Gel Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    JIN,Qing-Hui(金庆辉); CHEN,Ji-Feng(陈继锋); JING,Feng-Xiang(景奉香); ZHAO,Jian-Long(赵建龙); XU,Yuan-Sen(徐元森)

    2002-01-01

    The technique of microchip gel electrophoresis (MCGE) was used to analyze the polymerase chain reaction (PCR) products of M. tuberculosis Genome stained by ethidium bromide. The electrophoretic process was completed within 3-4 min and the results show that the technique of microchip electrophoresis is a high-speed and high-sensitivity analyzing method.

  20. High—Speed Analyzing PCR Products of M.tuberculosis Genome Stained by Ethidium Bromide on Microchip Gel Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    金庆辉; 陈继锋; 等

    2002-01-01

    The technique of microchip gel electrophoresis(MCGE) was used to analyze the polymerase chain reaction (PCR) products of M.tuberculosis Genome stained by ethidium bromide,The electrophoretic Process was completed within 3-4 min and the results show that the technique of microchip electrophoresis is a high-speed and high-sensitivity analyzing method.

  1. A new control strategy with saturation effect compensation for an autonomous induction generator driven by wide speed range turbines

    Energy Technology Data Exchange (ETDEWEB)

    Margato, Elmano, E-mail: efmargato@isel.ipl.p [Instituto Superior de Engenharia de Lisboa, DEEA, Av. Cons. Emidio Navarro 1, 1950-062 Lisboa (Portugal); Centro de Electrotecnia e Electronica Industrial, Av. Cons. Emidio Navarro 1, 1950-062 Lisboa (Portugal); Center for Inovation in Electrical and Energy Engineering, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Faria, Jose, E-mail: josefaria@netvisao.p [Instituto Superior de Engenharia de Lisboa, DEEA, Av. Cons. Emidio Navarro 1, 1950-062 Lisboa (Portugal); Centro de Electrotecnia e Electronica Industrial, Av. Cons. Emidio Navarro 1, 1950-062 Lisboa (Portugal); Resende, M.J., E-mail: mresende@ist.utl.p [Center for Inovation in Electrical and Energy Engineering, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Instituto Superior Tecnico, DEEC, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Palma, Joao, E-mail: jpalma@lnec.p [Centro de Electrotecnia e Electronica Industrial, Av. Cons. Emidio Navarro 1, 1950-062 Lisboa (Portugal); Laboratorio Nacional de Engenharia Civil, LNEC, Av. Brasil 101, 1700-066 (Portugal)

    2011-05-15

    Research highlights: {yields} A novel control strategy for autonomous induction generators with variable rotor speed. {yields} Generator excitation achieved using a current controlled voltage source inverter. {yields} Machine optimized use with stability and saturation effect compensation. {yields} Both saturation and cross-saturation effects discussed upon generator modeling. {yields} Efficient excitation and continuous load voltage control in a wide rotor speed range. -- Abstract: This paper presents a variable speed autonomous squirrel cage generator excited by a current-controlled voltage source inverter to be used in stand-alone micro-hydro power plants. The paper proposes a system control strategy aiming to properly excite the machine as well as to achieve the load voltage control. A feed-forward control sets the appropriate generator flux by taking into account the actual speed and the desired load voltage. A load voltage control loop is used to adjust the generated active power in order to sustain the load voltage at a reference value. The control system is based on a rotor flux oriented vector control technique which takes into account the machine saturation effect. The proposed control strategy and the adopted system models were validated both by numerical simulation and by experimental results obtained from a laboratory prototype. Results covering the prototype start-up, as well as its steady-state and dynamical behavior are presented.

  2. Research on flight stability performance of rotor aircraft based on visual servo control method

    Science.gov (United States)

    Yu, Yanan; Chen, Jing

    2016-11-01

    control method based on visual servo feedback is proposed, which is used to improve the attitude of a quad-rotor aircraft and to enhance its flight stability. Ground target images are obtained by a visual platform fixed on aircraft. Scale invariant feature transform (SIFT) algorism is used to extract image feature information. According to the image characteristic analysis, fast motion estimation is completed and used as an input signal of PID flight control system to realize real-time status adjustment in flight process. Imaging tests and simulation results show that the method proposed acts good performance in terms of flight stability compensation and attitude adjustment. The response speed and control precision meets the requirements of actual use, which is able to reduce or even eliminate the influence of environmental disturbance. So the method proposed has certain research value to solve the problem of aircraft's anti-disturbance.

  3. Hover performance estimation and validation of battery powered vertical takeoff and landing aircraft

    Institute of Scientific and Technical Information of China (English)

    王波; 侯中喜; 鲁亚飞; 朱雄峰

    2016-01-01

    Battery powered vertical takeoff and landing (VTOL) aircraft attracts more and more interests from public, while limited hover endurance hinders many prospective applications. Based on the weight models of battery, motor and electronic speed controller, the power consumption model of propeller and the constant power discharge model of battery, an efficient method to estimate the hover endurance of battery powered VTOL aircraft was presented. In order to understand the mechanism of performance improvement, the impacts of propulsion system parameters on hover endurance were analyzed by simulations, including the motor power density, the battery capacity, specific energy and Peukert coefficient. Ground experiment platform was established and validation experiments were carried out, the results of which showed a well agreement with the simulations. The estimation method and the analysis results could be used for optimization design and hover performance evaluation of battery powered VTOL aircraft.

  4. Aircraft conceptual design study of the canard and threesurface unconventional configurations for the purposes of reducing environmental impacts

    Science.gov (United States)

    Desharnais, Olivier

    With a constant increase in the demand for air transport and today's high fuel price, the aerospace industry is actively searching for new operation methods and technologies to improve efficiency and to reduce the impact it has on the environment. Aircraft manufacturers are exploring many different ways of designing and building better airplanes. One of the considered methods is the use of unconventional aircraft configurations. The objective of this research is to study two configurations, the canard and three-surface, by applying them into a typical high-speed jet aircraft using the conceptual design tools for conventional aircraft available at Bombardier Aerospace (some of them have been modified and validated for the two configurations of interest). This included a weight estimation of the foreplane, an extensive validation of the aerodynamic tool, AVL, and a modification of a physics-based tail-sizing tool. The last tool was found necessary for an accurate foreplane/tailplane sizing, aircraft balancing, establishing the CG envelope and for the assessment of all stability and control requirements. Then, a canard aircraft comparable to the Bombardier research platform aircraft was designed. Final solutions were not obtained from a complete optimization because of some limitations in the design process. The preliminary results show an increase of fuel burn of 10%, leading to an increase of the environmental impacts. The theoretical advantage of not generating any download lift is clearly overwhelmed by the poor effectiveness of the high-lift system. The incapacity to reach a level of high-lift performance close to the one of conventional high-speed aircrafts mostly explains why the canard configuration was found to have no true benefits in this application. Even if no final solution of a three-surface aircraft was obtained in this research, this configuration was identified as being better than the canard case according to the information found in the literature

  5. 9x15 Low Speed Wind Tunnel Acoustic Improvements

    Science.gov (United States)

    Stark, David; Stephens, David

    2016-01-01

    The 9- by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) at NASA Glenn Research Center was built in 1969 in the return leg of the 8- by 6-Foot Supersonic Wind Tunnel (8x6 SWT). The 8x6 SWT was completed in 1949 and acoustically treated to mitigate community noise issues in 1950. This treatment included the addition of a large muffler downstream of the 8x6 SWT test section and diffuser. The 9x15 LSWT was designed for performance testing of VSTOL aircraft models, but with the addition of the current acoustic treatment in 1986 the tunnel has been used principally for acoustic and performance testing of aircraft propulsions systems. The present document describes an anticipated acoustic upgrade to be completed in 2017.

  6. Is the scaling of swim speed in sharks driven by metabolism?

    Science.gov (United States)

    Jacoby, David M P; Siriwat, Penthai; Freeman, Robin; Carbone, Chris

    2015-12-01

    The movement rates of sharks are intrinsically linked to foraging ecology, predator-prey dynamics and wider ecosystem functioning in marine systems. During ram ventilation, however, shark movement rates are linked not only to ecological parameters, but also to physiology, as minimum speeds are required to provide sufficient water flow across the gills to maintain metabolism. We develop a geometric model predicting a positive scaling relationship between swim speeds in relation to body size and ultimately shark metabolism, taking into account estimates for the scaling of gill dimensions. Empirical data from 64 studies (26 species) were compiled to test our model while controlling for the influence of phylogenetic similarity between related species. Our model predictions were found to closely resemble the observed relationships from tracked sharks, providing a means to infer mobility in particularly intractable species.

  7. The Scholarly Communication Speed of Library and Information Science Open Access Journals as Measured by First-Citation

    Directory of Open Access Journals (Sweden)

    Tai-Chi Yu

    2016-06-01

    Full Text Available Based on the time of journal article first-citation appearance, this study analyzed the citation speeds of Open Access (OA journals within Library and Information Science (LIS field indexed in Scopus and WoS database. Articles published between 2010 and 2014 by a total of 8 Full-OA journals and 13 Hybrid-OA journals indexed by 2010-2013 edition of JCR were collected and analyzed in June 2015. Results showed that there were 639 articles being cited in Scopus and the average firstcitation speed was 1.17 year. On the other hand, there were 434 articles being cited in WoS with a slightly higher first-time citation rate of 1.37 year. Most of the articles studied were cited for the first time in the same year or the year after of its publication. There were some articles being cited even before its official publication. Within the Hybrid-OA journals, articles belong to the OA mechanism did have shorter speed citation time than non-OA ones. This study suggested that further studies could adopt the concept of Altmetrics to investigate the first-usage speeds through the formal and informal communication channels. [Article content in Chinese

  8. Tailoring in risk communication by linking risk profiles and communication preferences: The case of speeding of young car drivers.

    Science.gov (United States)

    Geber, Sarah; Baumann, Eva; Klimmt, Christoph

    2016-12-01

    Speeding is one of the most relevant risk behaviors for serious and fatal accidents, particularly among young drivers. This study presents a tailoring strategy for anti-speeding communication. By referring to their motivational dispositions toward speeding derived from motivational models of health behavior, young car drivers were segmented into different risk groups. In order to ensure that risk communication efforts would actually be capable to target these groups, the linkage between the risk profiles and communication preferences were explored. The study was conducted on the basis of survey data of 1168 German car drivers aged between 17 and 24 years. The data reveal four types of risk drivers significantly differing in their motivational profiles. Moreover, the findings show significant differences in communication habits and media use between these risk groups. By linking the risk profiles and communication preferences, implications for tailoring strategies of road safety communication campaigns are derived. Promising segmentation and targeting strategies are discussed also beyond the current case of anti-speeding campaigns.

  9. Research on the measurement of belt speed by video in coal mine based on improved template matching algorithm

    Institute of Scientific and Technical Information of China (English)

    ZHU Ai-chun; HUA Wei; WANG Chun; WANG Yong-xing

    2011-01-01

    In order to improve the intelligence of video monitoring system of belt and make up the deficiency of higher failure rate and bad real-time performance in the traditional systems of measurement of belt speed,according to the fact that the light of coal mine is uneven,the strength of light changes greatly,the direction of belt movement is constant,and the position of camera was fixed,various algorithms of speed measurement by video were studied,and algorithm for template matching based on sum of absolute differences(SAD)and correlation coefficient was proposed and improved,besides,the tracking of feature regions was realized.Then,a camera calibration method using the invariance of the cross-ratio was adopted and the real-time measurement of belt speed by the hardware platform based on DM642 was realized.Finally,experiment results show that this method not only has advantages of high precision and strong anti-jamming capability but also can real-time reflect the changes of belt speed,so it has a comprehensive applicability.

  10. Wave speed in human coronary arteries is not influenced by microvascular vasodilation: implications for wave intensity analysis.

    Science.gov (United States)

    Rolandi, M Cristina; De Silva, Kalpa; Lumley, Matthew; Lockie, Timothy P E; Clapp, Brian; Spaan, Jos A E; Perera, Divaka; Siebes, Maria

    2014-03-01

    Wave intensity analysis and wave separation are powerful tools for interrogating coronary, myocardial and microvascular physiology. Wave speed is integral to these calculations and is usually estimated by the single-point technique (SPc), a feasible but as yet unvalidated approach in coronary vessels. We aimed to directly measure wave speed in human coronary arteries and assess the impact of adenosine and nitrate administration. In 14 patients, the transit time Δt between two pressure signals was measured in angiographically normal coronary arteries using a microcatheter equipped with two high-fidelity pressure sensors located Δs = 5 cm apart. Simultaneously, intracoronary pressure and flow velocity were measured with a dual-sensor wire to derive SPc. Actual wave speed was calculated as DNc = Δs/Δt. Hemodynamic signals were recorded at baseline and during adenosine-induced hyperemia, before and after nitroglycerin administration. The energy of separated wave intensity components was assessed using SPc and DNc. At baseline, DNc equaled SPc (15.9 ± 1.8 vs. 16.6 ± 1.5 m/s). Adenosine-induced hyperemia lowered SPc by 40 % (p DNc remained unchanged, leading to marked differences in respective separated wave energies. Nitroglycerin did not affect DNc, whereas SPc transiently fell to 12.0 ± 1.2 m/s (p < 0.02). Human coronary wave speed is reliably estimated by SPc under resting conditions but not during adenosine-induced vasodilation. Since coronary wave speed is unaffected by microvascular dilation, the SPc estimate at rest can serve as surrogate for separating wave intensity signals obtained during hyperemia, thus greatly extending the scope of WIA to study coronary physiology in humans.

  11. Importance of a finite speed of heat propagation in metals irradiated by femtosecond laser pulses

    Science.gov (United States)

    Klossika, J. J.; Gratzke, U.; Vicanek, M.; Simon, G.

    1996-10-01

    We study theoretically the propagation of heat in a metal, due to irradiation with an ultrashort laser pulse. The target is treated in an extended two-fluid model for electrons and phonons, which accounts for a finite speed of heat propagation in the electron gas. As a result, the absorbed laser energy is more localized in the electronic system yielding an enhanced peak electron temperature.

  12. Optimal Fuzzy Controller Tuned by TV-PSO for Induction Motor Speed Control

    Directory of Open Access Journals (Sweden)

    KULIC, F.

    2011-02-01

    Full Text Available This paper reports an automated procedure for the design of an optimal fuzzy logic controller to be used as an induction motor speed controller. The procedure consists of selection of a suitable well known fuzzy logic controller and tuning via particle swarm optimization optimal for the selected criteria. In this way the time required for tuning of the controller is significantly reduced in comparison with trial and error methods. As a benchmark a proportional-integral (PI controller is used. The PI controller is tuned via the symmetrical optimum procedure, the standard procedure for tuning a speed controller of an induction motor. Simulation results are obtained via a mathematical model developed in Matlab/Simulink. Experimental verification is carried out with a laboratory model based on the DS1104 digital control card. To minimize iron losses and to provide better motor performance for low loads, flux is reduced from nominal and speed is kept below nominal. Results are presented in tables and graphics. The optimal fuzzy logic controller provides a slight practical advantage.

  13. Fault Diagnosis and Fault Handling for Autonomous Aircraft

    DEFF Research Database (Denmark)

    Hansen, Søren

    Unmanned Aerial vehicles (UAVs) or drones are used increasingly for missions where piloted aircraft are unsuitable. The unmanned aircraft has a number of advantages with respect to size, weight and manoeuvrability that makes it possible for them to solve tasks that an aircraft previously has been...... that the fault is discovered in time such that appropriate actions can be taken. That could either be the aircraft controlling computer taking the fault into account or a human operator that intervenes. Detection of faults that occur during flight is exactly the subject of this thesis. Safety towards faults...... to another type of aircraft with different parameters. Amongst the main findings of this research project is a method to handle faults on the UAV’s pitot tube, which measures the aircraft speed. A set of software redundancies based on GPS velocity information and engine thrust are used to detect abnormal...

  14. New sonic shockwave multi-element sensors mounted on a small airfoil flown on F-15B testbed aircraft

    Science.gov (United States)

    1996-01-01

    An experimental device to pinpoint the location of a shockwave that develops in an aircraft flying at transonic and supersonic speeds was recently flight-tested at NASA's Dryden Flight Research Center, Edwards, California. The shock location sensor, developed by TAO Systems, Hampton, Va., utilizes a multi-element hot-film sensor array along with a constant-voltage anemometer and special diagnostic software to pinpoint the exact location of the shockwave and its characteristics as it develops on an aircraft surface. For this experiment, the 45-element sensor was mounted on the small Dryden-designed airfoil shown in this illustration. The airfoil was attached to the Flight Test Fixture mounted underneath the fuselage of Dryden's F-15B testbed aircraft. Tests were flown at transonic speeds of Mach 0.7 to 0.9, and the device isolated the location of the shock wave to within a half-inch. Application of this technology could assist designers of future supersonic aircraft in improving the efficiency of engine air inlets by controlling the shockwave, with a related improvement in aircraft performance and fuel economy.

  15. A CFD-based analysis of the 14-Bis aircraft aerodynamics and stability

    Directory of Open Access Journals (Sweden)

    Leonardo Ostan Bitencourt

    2011-05-01

    Full Text Available The work reported in the present paper was performed to honor the centennial of the flight by Alberto Santos Dumont with his 14-Bis aircraft. The paper describes results for a computational fluid dynamics (CFD analysis of the 14-Bis aircraft aerodynamics and flight stability. The 14-Bis aircraft geometry was generated from historical sources and observations. CFD computations were performed using well-established commercial codes for calculation of the historical flight conditions. Simulations considered a Reynolds-averaged Navier-Stokes formulation, in which turbulence closure was achieved by using Menter's model. The flight conditions investigated were primarily concerned with historical observations regarding flight speeds and the need for a more powerful engine, as well as flight stability characteristics of the 14-Bis airplane, which are unknown up to the present day. The results led to qualitative agreement with historical reports, although quite interesting conclusions could be drawn with regard to the actual aerodynamic flight speeds and the aircraft stability parameters.

  16. Improving aircraft conceptual design - A PHIGS interactive graphics interface for ACSYNT

    Science.gov (United States)

    Wampler, S. G.; Myklebust, A.; Jayaram, S.; Gelhausen, P.

    1988-01-01

    A CAD interface has been created for the 'ACSYNT' aircraft conceptual design code that permits the execution and control of the design process via interactive graphics menus. This CAD interface was coded entirely with the new three-dimensional graphics standard, the Programmer's Hierarchical Interactive Graphics System. The CAD/ACSYNT system is designed for use by state-of-the-art high-speed imaging work stations. Attention is given to the approaches employed in modeling, data storage, and rendering.

  17. Structural Diagnostics of CFRP Composite Aircraft Components by Ultrasonic Guided Waves and Built-In Piezoelectric Transducers

    Energy Technology Data Exchange (ETDEWEB)

    Matt, Howard M. [Univ. of California, San Diego, CA (United States)

    2006-01-01

    To monitor in-flight damage and reduce life-cycle costs associated with CFRP composite aircraft, an autonomous built-in structural health monitoring (SHM) system is preferred over conventional maintenance routines and schedules. This thesis investigates the use of ultrasonic guided waves and piezoelectric transducers for the identification and localization of damage/defects occurring within critical components of CFRP composite aircraft wings, mainly the wing skin-to-spar joints. The guided wave approach for structural diagnostics was demonstrated by the dual application of active and passive monitoring techniques. For active interrogation, the guided wave propagation problem was initially studied numerically by a semi-analytical finite element method, which accounts for viscoelastic damping, in order to identify ideal mode-frequency combinations sensitive to damage occurring within CFRP bonded joints. Active guided wave tests across three representative wing skin-to-spar joints at ambient temperature were then conducted using attached Macro Fiber Composite (MFC) transducers. Results from these experiments demonstrate the importance of intelligent feature extraction for improving the sensitivity to damage. To address the widely neglected effects of temperature on guided wave base damage identification, analytical and experimental analyses were performed to characterize the influence of temperature on guided wave signal features. In addition, statistically-robust detection of simulated damage in a CFRP bonded joint was successfully achieved under changing temperature conditions through a dimensionally-low, multivariate statistical outlier analysis. The response of piezoceramic patches and MFC transducers to ultrasonic Rayleigh and Lamb wave fields was analytically derived and experimentally validated. This theory is useful for designing sensors which possess optimal sensitivity toward a given mode-frequency combination or for predicting the frequency dependent

  18. MODIFICATION OF CARBON STEEL BY LASER SURFACE MELTING: PART I: EFFECT OF LASER BEAM TRAVELLING SPEED ON MICROSTRUCTURAL FEATURES AND SURFACE HARDNESS

    Directory of Open Access Journals (Sweden)

    Hashem F. El-Labban

    2013-01-01

    Full Text Available The present study aims to improve the surface hardness of carbon steel by application of laser surface melting of effective conditions. The travelling speed of laser beam during this treatment is one of the important treatment conditions. This study aims to investigate the effect of laser surface melting with different beam speeds on macro and microstructure as well as the hardness distribution through the thickness of carbon steel. To achieve this target, three different travelling speeds (1500, 1000 and 500 mm min-1 at a constant beam power of 800 W were chosen in this study. The resulted laser treated specimens were investigated in macro and microscopically scale using optical and scanning electron microscope. Hardness measurements were also carried out through the thickness of the laser treated specimens. The laser treated areas with all used travelling speeds results in melted and solidified zone on the surface of the steel. In the same time, Plates of acicular martensite structure were observed within the upper part of the melted and solidified zone in almost all experimental conditions, while some bainite structure in ferrite grains are detected in its lower part. By increasing the travelling speed, the depth of the laser treated zone was decreases, while travelling speed has much less significant effect on the laser treated zone width. The size of the formed martensite plates was increased by decreasing the travelling speed from 1500 to 500 mm min-1. On the other hand, the travelling speed has a straight effect on the length of the acicular martensite; as the travelling speed increases, the acicular martensite became longer, while it shows fine acicular martensite at lower travelling speeds. The depth that full martensite structure can be reached is increased by increasing travelling speed. At lower travelling speed (500 mm min-1, large amount of bainite structure is observed at the center of the treated zone up to its lower end. The

  19. Development of an ultrasonic pulse-echo (UPE) technique for aircraft icing studies

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yang; Hu, Hui [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); Chen, Wen-Li [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); School of Civil Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090 (China); Bond, Leonard J. [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, 151 ASC II, Ames, IA 50011 (United States)

    2014-02-18

    Aircraft operating in some cold weather conditions face the risk of icing. Icing poses a threat to flight safety and its management is expensive. Removing light frost on a clear day from a medium-size business jet can cost $300, heavy wet snow removal can cost $3,000 and removal of accumulated frozen/freezing rain can cost close to $10,000. Understanding conditions that lead to severe icing events is important and challenging. When an aircraft or rotorcraft flies in a cold climate, some of the super cooled droplets impinging on exposed aircraft surfaces may flow along the surface prior to freezing and give various forms and shapes of ice. The runback behavior of a water film on an aircraft affects the morphology of ice accretion and the rate of formation. In this study, we report the recent progress to develop an Ultrasonic Pulse-Echo (UPE) technique to provide real-time thickness distribution measurements of surface water flows driven by boundary layer airflows for aircraft icing studies. A series of initial experimental investigations are conducted in an ice wind tunnel employing an array of ultrasonic transducers placed underneath the surface of a flat plate. The water runback behavior on the plate is evaluated by measuring the thickness profile variation of the water film along the surface by using the UPE technique under various wind speed and flow rate conditions.

  20. Speed mathematics

    CERN Document Server

    Handley, Bill

    2012-01-01

    This new, revised edition of the bestselling Speed Mathematics features new chapters on memorising numbers and general information, calculating statistics and compound interest, square roots, logarithms and easy trig calculations. Written so anyone can understand, this book teaches simple strategies that will enable readers to make lightning-quick calculations. People who excel at mathematics use better strategies than the rest of us; they are not necessarily more intelligent. With Speed Mathematics you'll discover methods to make maths easy and fun. This book is perfect for stud

  1. Speed enforcement in Norway

    DEFF Research Database (Denmark)

    Elvik, Rune

    2015-01-01

    This paper probes the relationship between changes in the risk of apprehension for speeding in Norway and changes in the amount of speeding. The paper is based on a game-theoretic model of how the rate of violations and the amount of enforcement is determined by the interaction between drivers...

  2. Unmanned aircraft systems

    Science.gov (United States)

    Unmanned platforms have become increasingly more common in recent years for acquiring remotely sensed data. These aircraft are referred to as Unmanned Airborne Vehicles (UAV), Remotely Piloted Aircraft (RPA), Remotely Piloted Vehicles (RPV), or Unmanned Aircraft Systems (UAS), the official term used...

  3. Handler, bystander and reentry exposure to TCDD from application of Agent Orange by C-123 aircraft during the Vietnam War.

    Science.gov (United States)

    Ross, John H; Hewitt, Andrew; Armitage, James; Solomon, Keith; Watkins, Deborah K; Ginevan, Michael E

    2015-02-01

    Using validated models and methods routinely employed by pesticide regulatory agencies, the absorbed dosages of Agent Orange (AO) herbicide contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were estimated for mixer/loaders, applicators, and individuals in the vicinity of applications of AO by C-123 aircraft during the Vietnam War. Resulting dosages of TCDD were then transformed to estimates of adipose residues, and compared to population biomonitoring of known mixer/loaders and applicators as well as ground troops in Vietnam and civilians in the U.S. Results demonstrate that mixer/loaders and applicators had the greatest exposures and their measured residues of TCDD in adipose were consistent with the estimated exposures. Further, the potentially exposed ground troops, including those who could have been directly sprayed during aerial defoliation, had measured adipose residues that were consistent with those in civilian U.S. populations with no defined source of exposure exposures and both of those cohorts had orders of magnitude less exposure than the mixer/loaders or applicators. Despite the availability of validated exposure modeling methods for decades, the quantitative TCDD dose estimates presented here are the first of their kind for the Vietnam conflict.

  4. FINITE ELEMENT ANALYSIS FOR CHIP FORMATION IN HIGH SPEED TURNING OPERATIONS BY ARBITRARY LAGRANGIAN EULERIAN METHOD

    Institute of Scientific and Technical Information of China (English)

    USAMA Umer; XIE Lijing; WANG Xibin

    2006-01-01

    A two-dimensional finite element (FE) model for the high speed turning operations when orthogonally machining AISI H13 tool steel at 49HRC using poly crystalline cubic boron nitride(PCBN) is described. An arbitrary Lagrangian Eulerian (ALE) method has been adopted which does not need any chip separation criteria as opposed to the traditional Lagrangian approach. Through FE simulations temperature and stresses distributions are presented that could be helpful in predicting tool life and improving process parameters. The results show that high temperatures are generated along the tool rake face as compared to the shear zone temperatures due to high thermal conductivity of PCBN tools.

  5. Inspection of Powder Flow During LMD Deposition by High Speed Imaging

    Science.gov (United States)

    Montero, Javier; Rodríguez, Ángel; Amado, José Manuel; Yáñez, Armando J.

    Laser cladding and LMD (Laser Metal Deposition) processes are continuously gaining ground in aerospace and energy industries. One of the known issues with that kind of processes is the difficulty of maintaining a constant and well distributed powder flow mass rate between the nozzle and the substrate. In this work, a method for real time inspection of powder distribution and mass flow rate is presented. Inference of mass flow rate and powder distribution is made using a high speed camera and a laser illumination device. Both on-process and off-process monitoring can be achieved. Different experimental results for the validation of the proposed method are presented.

  6. High performance forward swept wing aircraft

    Science.gov (United States)

    Koenig, David G. (Inventor); Aoyagi, Kiyoshi (Inventor); Dudley, Michael R. (Inventor); Schmidt, Susan B. (Inventor)

    1988-01-01

    A high performance aircraft capable of subsonic, transonic and supersonic speeds employs a forward swept wing planform and at least one first and second solution ejector located on the inboard section of the wing. A high degree of flow control on the inboard sections of the wing is achieved along with improved maneuverability and control of pitch, roll and yaw. Lift loss is delayed to higher angles of attack than in conventional aircraft. In one embodiment the ejectors may be advantageously positioned spanwise on the wing while the ductwork is kept to a minimum.

  7. Comparisons of cloud ice mass content retrieved from the radar-infrared radiometer method with aircraft data during the second international satellite cloud climatology project regional experiment (FIRE-II)

    Energy Technology Data Exchange (ETDEWEB)

    Matrosov, S.Y. [Univ. of Colorado, Boulder, CO (United States)]|[National Oceanic and Atmospheric Administration Environmental Technology Lab., Boulder, CO (United States); Heymsfield, A.J. [National Center for Atmospheric Research, Boulder, CO (United States); Kropfli, R.A.; Snider, J.B. [National Oceanic and Atmospheric Administration Environmental Technology Lab., Boulder, CO (United States)

    1996-04-01

    Comparisons of remotely sensed meteorological parameters with in situ direct measurements always present a challenge. Matching sampling volumes is one of the main problems for such comparisons. Aircraft usually collect data when flying along a horizontal leg at a speed of about 100 m/sec (or even greater). The usual sampling time of 5 seconds provides an average horizontal resolution of the order of 500 m. Estimations of vertical profiles of cloud microphysical parameters from aircraft measurements are hampered by sampling a cloud at various altitudes at different times. This paper describes the accuracy of aircraft horizontal and vertical coordinates relative to the location of the ground-based instruments.

  8. Preparative separation of high-purity cordycepin from Cordyceps militaris(L.) Link by high-speed countercurrent chromatography

    Science.gov (United States)

    Zhu, Licai; Liang, Yong; Lao, Deqiang; Zhang, Tianyou; Ito, Yoichiro

    2009-01-01

    A high-speed counter-current chromatography (HSCCC) technique in a preparative scale has been applied to separate and purify cordycepin from the extract of Cordyceps militaris(L.) Link by a one-step separation. A high efficiency of HSCCC separation was achieved on a two-phase solvent system of n-hexane–n-butanol–methanol–water (23:80:30:155, v/v/v/v) by eluting the lower mobile phase at a flow rate of 2 ml/min under a revolution speed of 850 rpm. HSCCC separation of 216.2 mg crude sample (contained cordycepin at 44.7% purity after 732 cation-exchange resin clean-up) yielded 64.8 mg cordycepin with purity of 98.9% and 91.7% recovery. Identification of the target compound was performed by UV, IR, MS, 1H NMR and 13C NMR. PMID:21643461

  9. Experimental investigation on dynamic response of aircraft panels excited by high-intensity acoustic loads in thermal environment

    Science.gov (United States)

    WU, Z. Q.; LI, H. B.; ZHANG, W.; CHENG, H.; KONG, F. J.; LIU, B. R.

    2016-09-01

    Metallic and composite panels are the major components for thermal protection system of aircraft vehicles, which are exposed to a severe combination of aerodynamic, thermal and acoustic environments during hypersonic flights. A thermal-acoustic testing apparatus which simulates thermal and acoustic loads was used to validate the integrity and the reliability of these panels. Metallic and ceramic matrix composite flat panels were designed. Dynamic response tests of these panels were carried out using the thermal acoustic apparatus. The temperature of the metallic specimen was up to 400 °C, and the temperature of the composite specimen was up to 600 °C. Moreover, the acoustic load was over 160 dB. Acceleration responses of these testing panels were measured using high temperature instruments during the testing process. Results show that the acceleration root mean square values are dominated by sound pressure level of acoustic loads. Compared with testing data in room environment, the peaks of the acceleration dynamic response shifts obviously to the high frequency in thermal environment.

  10. Arc reattachment driven by a turbulent boundary layer: implications for the sweeping of lightning arcs along aircraft

    Science.gov (United States)

    Guerra-Garcia, C.; Nguyen, N. C.; Peraire, J.; Martinez-Sanchez, M.

    2016-09-01

    A lightning channel attached to an aircraft in flight will be swept along the aircraft’s surface in response to the relative velocity between the arc’s root (attached to a moving electrode) and the bulk of the arc, which is stationary with respect to the air. During this process, the reattachment of the arc to new locations often occurs. The detailed description of this swept stroke is still at an early stage of research, and it entails the interaction between an electrical arc and the flow boundary layer. In this paper we examine the implications of the structure of the boundary layer for the arc sweeping and reattachment process by considering different velocity profiles, both for laminar and turbulent flow, as well as a high fidelity description, using large eddy simulation, of transitional flow over an airfoil. It is found that the local velocity fluctuations in a turbulent flow may be important contributors to the reattachment of the arc, through a combination of an increased potential drop along the arc and local approaches of the arc to the surface. Specific flow features, such as the presence of a laminar recirculation bubble, can also contribute to the possibility of reattachment.

  11. Modelled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Science.gov (United States)

    Samset, B. H.; Myhre, G.; Herber, A.; Kondo, Y.; Li, S.-M.; Moteki, N.; Koike, M.; Oshima, N.; Schwarz, J. P.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Chin, M.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2014-11-01

    Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long-range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present-day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparison. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modelled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  12. Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Directory of Open Access Journals (Sweden)

    B. H. Samset

    2014-08-01

    Full Text Available Atmospheric black carbon (BC absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF. However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparision. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modeled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  13. Impact of the chosen turbulent flow empirical model on the prediction of sound radiation and vibration by aircraft panels

    Science.gov (United States)

    Rocha, Joana

    2016-07-01

    A precise definition of the turbulent boundary layer excitation is required to accurately predict the sound radiation and surface vibration levels, produced by an aircraft panel excited turbulent flow during flight. Hence, any existing inaccuracy on turbulent boundary layer excitation models leads to an inaccurate prediction of the panel response. A number of empirical models have been developed over the years to provide the turbulent boundary layer wall pressure spectral density. However, different empirical models provide dissimilar predictions for the wall pressure spectral density. The objective of the present study is to investigate and quantify the impact of the chosen empirical model on the predicted radiated sound power, and on the predicted panel surface acceleration levels. This study provides a novel approach and a detailed analysis on the use of different turbulent boundary layer wall pressure empirical models, and impact on mathematical predictions. Closed-form mathematical relationships are developed, and recommendations are provided for the level of deviation and uncertainty associated to different models, in relation to a baseline model, both for panel surface acceleration and radiated sound power.

  14. Developing Large-Scale Bayesian Networks by Composition: Fault Diagnosis of Electrical Power Systems in Aircraft and Spacecraft

    Science.gov (United States)

    Mengshoel, Ole Jakob; Poll, Scott; Kurtoglu, Tolga

    2009-01-01

    In this paper, we investigate the use of Bayesian networks to construct large-scale diagnostic systems. In particular, we consider the development of large-scale Bayesian networks by composition. This compositional approach reflects how (often redundant) subsystems are architected to form systems such as electrical power systems. We develop high-level specifications, Bayesian networks, clique trees, and arithmetic circuits representing 24 different electrical power systems. The largest among these 24 Bayesian networks contains over 1,000 random variables. Another BN represents the real-world electrical power system ADAPT, which is representative of electrical power systems deployed in aerospace vehicles. In addition to demonstrating the scalability of the compositional approach, we briefly report on experimental results from the diagnostic competition DXC, where the ProADAPT team, using techniques discussed here, obtained the highest scores in both Tier 1 (among 9 international competitors) and Tier 2 (among 6 international competitors) of the industrial track. While we consider diagnosis of power systems specifically, we believe this work is relevant to other system health management problems, in particular in dependable systems such as aircraft and spacecraft. (See CASI ID 20100021910 for supplemental data disk.)

  15. Euler Technology Assessment for Preliminary Aircraft Design: Compressibility Predictions by Employing the Cartesian Unstructured Grid SPLITFLOW Code

    Science.gov (United States)

    Finley, Dennis B.; Karman, Steve L., Jr.

    1996-01-01

    The objective of the second phase of the Euler Technology Assessment program was to evaluate the ability of Euler computational fluid dynamics codes to predict compressible flow effects over a generic fighter wind tunnel model. This portion of the study was conducted by Lockheed Martin Tactical Aircraft Systems, using an in-house Cartesian-grid code called SPLITFLOW. The Cartesian grid technique offers several advantages, including ease of volume grid generation and reduced number of cells compared to other grid schemes. SPLITFLOW also includes grid adaption of the volume grid during the solution to resolve high-gradient regions. The SPLITFLOW code predictions of configuration forces and moments are shown to be adequate for preliminary design, including predictions of sideslip effects and the effects of geometry variations at low and high angles-of-attack. The transonic pressure prediction capabilities of SPLITFLOW are shown to be improved over subsonic comparisons. The time required to generate the results from initial surface data is on the order of several hours, including grid generation, which is compatible with the needs of the design environment.

  16. Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Science.gov (United States)

    Samset, B. H.; Myhre, G.; Herber, A.; Kondo, Y.; Li, S.-M.; Moteki, N.; Koike, M.; Oshima, N.; Schwarz, J. P.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Chin, M.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2014-08-01

    Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparision. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modeled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  17. Aircraft Aerodynamic Parameter Detection Using Micro Hot-Film Flow Sensor Array and BP Neural Network Identification

    Science.gov (United States)

    Que, Ruiyi; Zhu, Rong

    2012-01-01

    Air speed, angle of sideslip and angle of attack are fundamental aerodynamic parameters for controlling most aircraft. For small aircraft for which conventional detecting devices are too bulky and heavy to be utilized, a novel and practical methodology by which the aerodynamic parameters are inferred using a micro hot-film flow sensor array mounted on the surface of the wing is proposed. A back-propagation neural network is used to model the coupling relationship between readings of the sensor array and aerodynamic parameters. Two different sensor arrangements are tested in wind tunnel experiments and dependence of the system performance on the sensor arrangement is analyzed. PMID:23112638

  18. Aircraft Cabin Environmental Quality Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Gundel, Lara; Kirchstetter, Thomas; Spears, Michael; Sullivan, Douglas

    2010-05-06

    The Indoor Environment Department at Lawrence Berkeley National Laboratory (LBNL) teamed with seven universities to participate in a Federal Aviation Administration (FAA) Center of Excellence (COE) for research on environmental quality in aircraft. This report describes research performed at LBNL on selecting and evaluating sensors for monitoring environmental quality in aircraft cabins, as part of Project 7 of the FAA's COE for Airliner Cabin Environmental Research (ACER)1 effort. This part of Project 7 links to the ozone, pesticide, and incident projects for data collection and monitoring and is a component of a broader research effort on sensors by ACER. Results from UCB and LBNL's concurrent research on ozone (ACER Project 1) are found in Weschler et al., 2007; Bhangar et al. 2008; Coleman et al., 2008 and Strom-Tejsen et al., 2008. LBNL's research on pesticides (ACER Project 2) in airliner cabins is described in Maddalena and McKone (2008). This report focused on the sensors needed for normal contaminants and conditions in aircraft. The results are intended to complement and coordinate with results from other ACER members who concentrated primarily on (a) sensors for chemical and biological pollutants that might be released intentionally in aircraft; (b) integration of sensor systems; and (c) optimal location of sensors within aircraft. The parameters and sensors were selected primarily to satisfy routine monitoring needs for contaminants and conditions that commonly occur in aircraft. However, such sensor systems can also be incorporated into research programs on environmental quality in aircraft cabins.

  19. Optimal camera exposure for video surveillance systems by predictive control of shutter speed, aperture, and gain

    Science.gov (United States)

    Torres, Juan; Menéndez, José Manuel

    2015-02-01

    This paper establishes a real-time auto-exposure method to guarantee that surveillance cameras in uncontrolled light conditions take advantage of their whole dynamic range while provide neither under nor overexposed images. State-of-the-art auto-exposure methods base their control on the brightness of the image measured in a limited region where the foreground objects are mostly located. Unlike these methods, the proposed algorithm establishes a set of indicators based on the image histogram that defines its shape and position. Furthermore, the location of the objects to be inspected is likely unknown in surveillance applications. Thus, the whole image is monitored in this approach. To control the camera settings, we defined a parameters function (Ef ) that linearly depends on the shutter speed and the electronic gain; and is inversely proportional to the square of the lens aperture diameter. When the current acquired image is not overexposed, our algorithm computes the value of Ef that would move the histogram to the maximum value that does not overexpose the capture. When the current acquired image is overexposed, it computes the value of Ef that would move the histogram to a value that does not underexpose the capture and remains close to the overexposed region. If the image is under and overexposed, the whole dynamic range of the camera is therefore used, and a default value of the Ef that does not overexpose the capture is selected. This decision follows the idea that to get underexposed images is better than to get overexposed ones, because the noise produced in the lower regions of the histogram can be removed in a post-processing step while the saturated pixels of the higher regions cannot be recovered. The proposed algorithm was tested in a video surveillance camera placed at an outdoor parking lot surrounded by buildings and trees which produce moving shadows in the ground. During the daytime of seven days, the algorithm was running alternatively together

  20. RESEARCH OF NIGHT LIGHT EFFECTS ON COLORIMETRIC CHARACTERISTICS OF IMAGE PERCEIVED BY THE PILOT IN AN AIRCRAFT COCKPIT

    Directory of Open Access Journals (Sweden)

    I. O. Zharinov

    2015-09-01

    Full Text Available Subject of Research. The influence of radiation spectra from the source of artificial night light on colorimetric characteristics of image perceived by the pilot in the aircraft cockpit has been studied. The image is displayed on the LCD screen of multifunctional color indication equipment unit. Night illumination of the cockpit is performed with the use of artificial lamps of red, green, blue and, rarely, white light. Method. Any given color to be displayed on the screen is perceived by an observer differently with presence and absence of external illumination. When external light of white color is used, perceived color depends upon color temperature of the light source; if illumination source has any arbitrary spectral characteristics, then perceivable color depends upon whole spectral content of the used source. The color, perceived by an observer, is formed as the mixture of the color displayed on the screen (image element color with the color presented by diffuse reflection of external illumination source from the surface of the screen. The brightness of both colors is added. Mathematical expressions, that define calculation rule for chromaticity coordinates of color perceived by an observer, are based on the Grassmann’s law of additive color mixing. Quantitative analysis of the effect, caused by radiation spectra from an external source of artificial light on color gamut area, corresponding to image, perceived by an observer, has been performed through simulation in MathCad 15.0. Main Results. It was shown, that the color palette of on-board indication equipment, obtained on automated working place for any preset source of external illumination of fluorescent spectrum, corresponding to white light, is not usable correctly in the aircraft night flight mode. An observer loses ability to perceive properly saturated primary colors of red and blue in the case of green-blue light source of external illumination; and the same issue occurs with

  1. Gain self-scheduled H∞ control for morphing aircraft in the wing transition process based on an LPV model

    Institute of Scientific and Technical Information of China (English)

    Yue Ting; Wang Lixin; Ai Junqiang

    2013-01-01

    This article investigates gain self-scheduled H∞ robust control system design for a tailless folding-wing morphing aircraft in the wing shape varying process.During the wing morphing phase,the aircraft's dynamic response will be governed by time-varying aerodynamic forces and moments.Nonlinear dynamic equations of the morphing aircraft are linearized by using Jacobian linearization approach,and a linear parameter varying (LPV) model of the morphing aircraft in wing folding is obtained.A multi-loop controller for the morphing aircraft is formulated to guarantee stability for the wing shape transition process.The proposed controller uses a set of inner-loop gains to provide stability using classical techniques,whereas a gain self-scheduled H∞ outer-loop controller is devised to guarantee a specific level of robust stability and performance for the time-varying dynamics.The closed-loop simulations show that speed and altitude vary slightly during the whole wing folding process,and they converge rapidly after the process ends.This proves that the gain self-scheduled H∞ robust controller can guarantee a satisfactory dynamic performance for the morphing aircraft during the whole wing shape transition process.Finally,the flight control system's robustness for the wing folding process is verified according to uncertainties of the aerodynamic parameters in the nonlinear model.

  2. Research on Emerging and Descending Aircraft Noise

    Directory of Open Access Journals (Sweden)

    Monika Bartkevičiūtė

    2013-12-01

    Full Text Available Along with an increase in the aircraft engine power and growth in air traffic, noise level at airports and their surrounding environs significantly increases. Aircraft noise is high level noise spreading within large radius and intensively irritating the human body. Air transport is one of the main sources of noise having a particularly strong negative impact on the environment. The article deals with activities and noises taking place in the largest nationwide Vilnius International Airport.The level of noise and its dispersion was evaluated conducting research on the noise generated by emerging and descending aircrafts in National Vilnius Airport. Investigation was carried out at 2 measuring points located in a residential area. There are different types of aircrafts causing different sound levels. It has been estimated the largest exceedances that occur when an aircraft is approaching. In this case, the noisiest types of aircrafts are B733, B738 and AT72. The sound level varies from 70 to 85 dBA. The quietest aircrafts are RJ1H and F70. When taking off, the equivalent of the maximum sound level value of these aircrafts does not exceed the authorized limits. The paper describes the causes of noise in aircrafts, the sources of origin and the impact of noise on humans and the environment.Article in Lithuanian

  3. Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhukhovitskii, D. I., E-mail: dmr@ihed.ras.ru; Fortov, V. E.; Molotkov, V. I.; Lipaev, A. M.; Naumkin, V. N. [Joint Institute of High Temperatures, Russian Academy of Sciences, Izhorskaya 13, Bd. 2, 125412 Moscow (Russian Federation); Thomas, H. M. [Research Group Complex Plasma, DLR, Oberpfaffenhofen, 82234 Wessling (Germany); Ivlev, A. V.; Morfill, G. E. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Schwabe, M. [Department of Chemical and Biomolecular Engineering, Graves Lab, D75 Tan Hall, University of California, Berkeley, CA 94720 (United States)

    2015-02-15

    We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are incompatible with the theory of ion acoustic waves. The estimate for the pressure in a strongly coupled Coulomb system and a scaling law for the complex plasma make it possible to derive an evaluation for the speed of sound, which is in a reasonable agreement with the experiments in complex plasmas.

  4. High-temperature and high-speed oxidation of 4H-SiC by atmospheric pressure thermal plasma jet

    Science.gov (United States)

    Hanafusa, Hiroaki; Ishimaru, Ryosuke; Higashi, Seiichiro

    2017-04-01

    The application of atmospheric pressure thermal plasma jet (TPJ) annealing to the high-temperature and high-speed thermal oxidation of Si-face of 4H-SiC wafer is reported. A high SiO2 film growth rate of 288 nm min‑1 was obtained at an oxidation temperature of 1640 °C without intentional dry O2 gas feeding. Ambient analysis suggested that ozone generated from oxygen in the ambient air by the plasma irradiation was supplied to the SiC surface. It is implied that a mono-oxygen decomposed from ozone was diffused into the oxide growth interface. As a result, high-speed oxidation occurred by combination of high-temperature TPJ annealing and ozone feeding.

  5. Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions

    CERN Document Server

    Zhukhovitskii, D I; Molotkov, V I; Lipaev, A M; Naumkin, V N; Thomas, H M; Ivlev, A V; Schwabe, M; Morfill, G E

    2014-01-01

    We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are fully incompatible with the theory of ion acoustic waves. We explore the analogy between a strongly coupled Coulomb system and a solid. A scaling law for the complex plasma makes it possible to derive a theoretical estimate for the speed of sound, which is in a reasonable agreement with the experiments in strongly coupled complex plasmas.

  6. The monitoring of transient regimes on machine tools based on speed, acceleration and active electric power absorbed by motors

    Science.gov (United States)

    Horodinca, M.

    2016-08-01

    This paper intend to propose some new results related with computer aided monitoring of transient regimes on machine-tools based on the evolution of active electrical power absorbed by the electric motor used to drive the main kinematic chains and the evolution of rotational speed and acceleration of the main shaft. The active power is calculated in numerical format using the evolution of instantaneous voltage and current delivered by electrical power system to the electric motor. The rotational speed and acceleration of the main shaft are calculated based on the signal delivered by a sensor. Three real-time analogic signals are acquired with a very simple computer assisted setup which contains a voltage transformer, a current transformer, an AC generator as rotational speed sensor, a data acquisition system and a personal computer. The data processing and analysis was done using Matlab software. Some different transient regimes were investigated; several important conclusions related with the advantages of this monitoring technique were formulated. Many others features of the experimental setup are also available: to supervise the mechanical loading of machine-tools during cutting processes or for diagnosis of machine-tools condition by active electrical power signal analysis in frequency domain.

  7. The refinement of the surface layer of HS 7425 high speed tool steel by laser and electric arc plasma

    Directory of Open Access Journals (Sweden)

    W. Bochnowski

    2008-10-01

    Full Text Available The paper present two different techniques: laser remelting surface and plasma remelting surface of the high speed steel HS 7425. Thestructure of the remelted layers were examined by means of SEM – microscopy. Measurement of microhardness in remelting zone usingVickers method. The remelting zone consist of dendritic cells and columnar crystals. Increase of hardness was observed in remelted zonein comparison to the substrate of the steel. The hardness in the remelted zone increases with the increasing cooling rate.

  8. Prediction and Analysis of Engine Friction Power of a Diesel Engine Influenced by Engine Speed, Load, and Lubricant Viscosity

    OpenAIRE

    Devendra Singh; Fengshou Gu; Fieldhouse, John D.; Nishan Singh; Singal, S. K.

    2014-01-01

    Automotive industries made a paradigm shift in selection of viscometrics of engine lubricant, from higher to lower viscosity grade, for improving fuel economy of vehicles. Engine fuel consumption is influenced by friction between the various engine components. Engine friction power (FP) of a direct injection diesel engine is calculated from the measured value of in-cylinder pressure signals at various operating conditions. For predicting FP, as a function of speed, load, and lubricant viscosi...

  9. Speed control of SR motor by self-tuning fuzzy PI controller with artificial neural network

    Indian Academy of Sciences (India)

    Ercument Karakas; Soner Vardarbasi

    2007-10-01

    In this work, the dynamic model, flux-current-rotor position and torque-current-rotor position values of the switched reluctance motor (SRM) are obtained in MATLAB/Simulink. Motor control speed is achieved by self-tuning fuzzy PI (Proportional Integral) controller with artificial neural network tuning (NSTFPI). Performance of NSTFPI controller is compared with performance of fuzzy logic (FL) and fuzzy logic PI (FLPI) controllers in respect of rise time, settling time, overshoot and steady state error

  10. A fully-autonomous hovercraft inspired by bees: wall following and speed control in straight and tapered corridors

    OpenAIRE

    Roubieu, Frédéric L.; Serres, Julien; Franceschini, Nicolas; Ruffier, Franck; Viollet, Stéphane

    2012-01-01

    International audience; The small autonomous vehicles of the future will have to navigate close to obstacles in highly unpredictable environments. Risky tasks of this kind may require novel sensors and control methods that differ from conventional approaches. Recent ethological findings have shown that complex navigation tasks such as obstacle avoidance and speed control are performed by flying insects on the basis of optic flow (OF) cues, although insects' compound eyes have a very poor spat...

  11. System Noise Assessment of Blended-Wing-Body Aircraft With Open Rotor Propulsion

    Science.gov (United States)

    Guo, Yueping; Thomas, Russell H.

    2015-01-01

    An aircraft system noise study is presented for the Blended-Wing-Body (BWB) aircraft concept with three open rotor engines mounted on the upper surface of the airframe. It is shown that for such an aircraft, the cumulative Effective Perceived Noise Level (EPNL) is about 24 dB below the current aircraft noise regulations of Stage 4. While this makes the design acoustically viable in meeting the regulatory requirements, even with the consideration of more stringent noise regulations of a possible Stage 5 in the next decade or so, the design will likely meet stiff competitions from aircraft with turbofan engines. It is shown that the noise levels of the BWB design are held up by the inherently high noise levels of the open rotor engines and the limitation on the shielding benefit due to the practical design constraint on the engine location. Furthermore, it is shown that the BWB design has high levels of noise from the main landing gear, due to their exposure to high speed flow at the junction between the center body and outer wing. These are also the reasons why this baseline BWB design does not meet the NASA N+2 noise goal of 42 dB below Stage 4. To identify approaches that may further reduce noise, parametric studies are also presented, including variations in engine location, vertical tail and elevon variations, and airframe surface acoustic liner treatment effect. These have the potential to further reduce noise but they are only at the conceptual stage.

  12. Probing dark energy perturbations: the dark energy equation of state and speed of sound as measured by WMAP

    CERN Document Server

    Bean, R; Bean, Rachel; Dore, Olivier

    2004-01-01

    We review the implications of having a non-trivial matter component in the universe and the potential for detecting such a component through the matter power spectrum and ISW effect. We adopt a phenomenological approach and consider the mysterious dark energy to be a cosmic fluid. It is thus fully characterized, up to linear order, by its equation of state and its speed of sound. Whereas the equation of state has been widely studied in the literature, less interest has been devoted to the speed of sound. Its observational consequences come predominantly from very large scale modes of dark matter perturbations ($k < 0.01 hmathrm{Mpc}^{-1}$). Since these modes have hardly been probed so far by large scale galaxy surveys, we investigate whether joint constraints that can be placed on those two quantities using the recent CMB fluctuations measurements by WMAP as well as the recently measured CMB large scale structure cross-correlation. We find only a tentative 1$sigma$ detection of the speed of sound, from CMB...

  13. The Digital Simulation of Synchronous Motors Fed by Voltage-Source Inverters Over Wide Speed and Frequency Ranges

    Science.gov (United States)

    Rowihal, Said Soliman

    Both voltage-source and current-source inverters are widely used for supplying three-phase power to induction motor drives, each having their advantages and disadvantages. For high power drives and applications requiring accurate speed and tracking coordination, the synchronous motors are the optimum choice. For constant speed applications of synchronous motor drives, current-source inverters tend to be favored as the motor can usually be operated in the overexcited leading power factor region, thus providing the inverter with sufficient electro-motive force to allow natural commutation. Generally speaking low speed operation of synchronous motors is not satisfactory from naturally commutated current-source inverters. To provide a dynamic range of speed and frequency would require expensive control circuitry and complicates the performance of the drive. The advantage of the voltage-source inverter for the wide range of speed and frequency control herein envisaged is that forced commutation is employed throughout the range and the commutating circuits have been well developed and established. On balance, voltage-source inverters represent a viable compromise for variable-speed three -phase synchronous motor drives including start-up. To investigate the transient response of the voltage -source fed-synchronous motor drives, a digital computer program is developed. The program is based on two models --machine model and inverter model. The machine is represented by a detailed two-axis model which includes the effects due to saliency, damper windings, and machine resistances. The inverter model represents a forced-commutated voltage-source inverter assuming ideal switching devices (thyristors and diodes). To cope with the wide variations of power factor during start-up, a thyristor with a reverse connected parallel diode are integrated as a bidirectional switch. The digital program provides the machine variables of interest (phase currents, field current, damper winding

  14. Microstructure and Eutectic Carbide Morphology of the High Speed Steel Strips Produced by Twin Roll Strip Casting Process

    Institute of Scientific and Technical Information of China (English)

    Hongshuang DI; Xiaoming ZHANG; Guodong WANG; Xianghua LIU

    2003-01-01

    The M2 high-speed steel strip was produced by using the laboratory scale twin roll strip caster. The microstructureand eutectic carbide morphology of thus produced products were observed and analyzed, and the comparison ofthose with conventional products was carried out. The effects of the processing parameters such as the meltingtemperature, the pouring temperature, rolling speed and separating force on the microstructure and eutectic carbidemorphology and their distribution were analyzed. The spheroidizing process of the strips in the annealing process wasinvestigated. The relations between the growth and spheroidizing of the eutectic carbide and the annealing technologywere obtained, and the mechanism of the twin roll strip casting process improving the eutectic carbide spheroidizingwas discussed. The theoretical instruction for determining the subsequent treatment process was provided.

  15. Serum induced degradation of 3D DNA box origami observed by high speed atomic force microscope

    DEFF Research Database (Denmark)

    Jiang, Zaixing; Zhang, Shuai; Yang, Chuanxu;

    2015-01-01

    3D DNA origami holds tremendous potential to encapsulate and selectively release therapeutic drugs. Observations of real-time performance of 3D DNA origami structures in physiological environment will contribute much to its further applications. Here, we investigate the degradation kinetics of 3D...... DNA box origami in serum using high-speed atomic force microscope optimized for imaging 3D DNA origami in real time. The time resolution allows characterizing the stages of serum effects on individual 3D DNA box origami with nanometer resolution. Our results indicate that the whole digest process...... is a combination of a rapid collapse phase and a slow degradation phase. The damages of box origami mainly happen in the collapse phase. Thus, the structure stability of 3D DNA box origami should be further improved, especially in the collapse phase, before clinical applications...

  16. Accelerated Curing Speed of Ethyl a-Cyanoacrylate by Polymer with Catecholamine Groups

    Institute of Scientific and Technical Information of China (English)

    张峰; 刘四委; 张艺; 许家瑞; 危岩

    2012-01-01

    Four kinds of poly(ethylene glycol) (PEG) derivatives with the similar backbone and different side groups have been synthesized successfully. When both catecholamine and double bond are tethered to polymer backbone, i.e., the PEG backbone, simultaneously, the polymer can accelerate the curing speed of ethyl a-cyanoacrylate (commer- cially available as 502) greatly under the same conditions (the curing time of such system is no more than 5 s). Probably this is due to the autoxidation of catecholamines. Through the redox-cycling, catecholamines can produce, collect free radicals, and thus initiate the free radical polymerization. Due to the fast-curing of such material when mixed with a-cyanoacrylate, we could design and develop a new bicomponent super bioglue used in the dentistry or other bioenvironment requiring super fast settlement for further surgical operations.

  17. Schlieren High Speed Imaging on Fluid Flow in Liquid Induced by Plasma-driven Interfacial Forces

    Science.gov (United States)

    Lai, Janis; Foster, John

    2016-10-01

    Effective plasma-based water purification depends heavily on the transport of plasma-derived reactive species from the plasma into the liquid. Plasma interactions at the liquid-gas boundary are known to drive circulation in the bulk liquid. This forced circulation is not well understood. A 2-D plasma- in-liquid water apparatus is currently being investigated as a means to study the plasma-liquid interface to understand not only reactive species flows but to also understand plasma- driven fluid dynamic effects in the bulk fluid. Using Schlieren high speed imaging, plasma-induced density gradients near the interfacial region and into the bulk solution are measured to investigate the nature of these interfacial forces. Plasma-induced flow was also measured using particle imaging velocimetry. NSF CBET 1336375 and DOE DE-SC0001939.

  18. Distributed Data Mining for Aircraft Health Management Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aircraft Flight Operations Quality Assurance (FOQA) programs are implemented by most of the aircraft operators. Vast amounts of FOQA data are distributed between...

  19. Genetic effects on information processing speed are moderated by age--converging results from three samples.

    Science.gov (United States)

    Ising, M; Mather, K A; Zimmermann, P; Brückl, T; Höhne, N; Heck, A; Schenk, L A; Rujescu, D; Armstrong, N J; Sachdev, P S; Reppermund, S

    2014-06-01

    Information processing is a cognitive trait forming the basis of complex abilities like executive function. The Trail Making Test (TMT) is a well-established test of information processing with moderate to high heritability. Age of the individual also plays an important role. A number of genetic association studies with the TMT have been performed, which, however, did not consider age as a moderating factor. We report the results of genome-wide association studies (GWASs) on age-independent and age-dependent TMT performance in two population-representative community samples (Munich Antidepressant Response Signature, MARS: N1 = 540; Ludwig Maximilians University, LMU: N2 = 350). Age-dependent genome-wide findings were then evaluated in a third sample of healthy elderly subjects (Sydney Memory and Ageing Study, Sydney MAS: N3 = 448). While a meta-analysis on the GWAS findings did not reveal age-independent TMT associations withstanding correction for multiple testing, we found a genome-wide significant age-moderated effect between variants in the DSG1 gene region and TMT-A performance predominantly reflecting visual processing speed (rs2199301, P(meta-analysis) = 1.3 × 10(-7)). The direction of the interaction suggests for the minor allele a beneficial effect in younger adults turning into a detrimental effect in older adults. The detrimental effect of the missense single nucleotide polymorphism rs1426310 within the same DSG1 gene region could be replicated in Sydney MAS participants aged 70-79, but not in those aged 80 years and older, presumably a result of survivor bias. Our findings demonstrate opposing effects of DSG1 variants on information processing speed depending on age, which might be related to the complex processes that DSG1 is involved with, including cell adhesion and apoptosis.

  20. Reversible control of kinesin activity and microtubule gliding speeds by switching the doping states of a conducting polymer support

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Brett D [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Velea, Luminita M [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Soto, Carissa M [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Whitaker, Craig M [US Naval Academy, Department of Chemistry, Annapolis, MD 21402 (United States); Gaber, Bruce P [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States); Ratna, Banahalli [US Naval Research Laboratory, Code 6930, Washington, DC 20375 (United States)

    2007-02-07

    We describe a method for reversibly controlling the ATPase activity of streptavidin-linked kinesin by changing the doping states of a conducting polymer support. When the polymer (poly(CH{sub 2}OH-EDOT)) was electrochemically switched from its dedoped (semiconducting) state to its doped (conducting) state, the ATPase activity of the adsorbed kinesin complex decreased by 35% with a concomitant decrease in the gliding speeds of kinesin-driven microtubules. When the polymer was switched back to its original dedoped state, nearly identical increases were observed in the kinesin ATPase activity and microtubule speeds. Use of a fluorescent ATP substrate analogue showed that the total amount of kinesin adsorbed on the poly(CH{sub 2}OH-EDOT) surface remained constant as the doping state of the polymer was switched. The microtubules exhibited nearly identical speed differences on the doped and dedoped surfaces for both chemical and electrochemical doping methods. Michaelis-Menten modelling suggests that the doped surface acts as an 'uncompetitive inhibitor' of kinesin. This work represents an investigation into the phenomenon of an electrically switchable surface exerting a moderating effect on the activity of an adsorbed protein that does not contain a bound, electroactive metal ion.

  1. Coronal Heating and Acceleration of the High/Low-Speed Solar Wind by Fast/Slow MHD Shock Trains

    CERN Document Server

    Suzuki, T K

    2004-01-01

    We investigate coronal heating and acceleration of the high- and low-speed solar wind in the open field region by dissipation of fast and slow magnetohydrodynamical (MHD) waves through MHD shocks. Linearly polarized \\Alfven (fast MHD) waves and acoustic (slow MHD) waves travelling upwardly along with a magnetic field line eventually form fast switch-on shock trains and hydrodynamical shock trains (N-waves) respectively to heat and accelerate the plasma. We determine one dimensional structure of the corona from the bottom of the transition region (TR) to 1AU under the steady-state condition by solving evolutionary equations for the shock amplitudes simultaneously with the momentum and proton/electron energy equations. Our model reproduces the overall trend of the high-speed wind from the polar holes and the low-speed wind from the mid- to low-latitude streamer except the observed hot corona in the streamer. The heating from the slow waves is effective in the low corona to increase the density there, and plays ...

  2. The application of the SAUNA CFD system to high and low speed vehicles

    Science.gov (United States)

    May, Nicholas E.; Peace, Andrew J.; Shaw, Jonathon A.

    1994-04-01

    The SAUNA grid generation and flow simulation system is applied to a variety of vehicles flows. The basic features and problems associated with predicting high speed external flows are discussed and contrasted with those associated with typical internal flows. Particular attention is paid in the discussion to turbulence modelling requirements. General descriptions of the grid generation philosophy adopted within the SAUNA system (structured, unstructured, hybrid) and the flow solution methodology are given. It is explained how the compressible flow algorithm may be modified to enable efficient calculation of low speed flows, thus extending the range of application of the SAUNA system to include conventional ground and sea vehicles. The grid generation capabilities of SAUNA are illustrated by showing examples of grids generated around configurations of a complete aircraft, a submarine and an automobile. The flow simulations are evaluated by comparison with experiment for several external high speed flows and a lower speed internal flow.

  3. Inverse modeling of the (137)Cs source term of the Fukushima Dai-ichi Nuclear Power Plant accident constrained by a deposition map monitored by aircraft.

    Science.gov (United States)

    Yumimoto, Keiya; Morino, Yu; Ohara, Toshimasa; Oura, Yasuji; Ebihara, Mitsuru; Tsuruta, Haruo; Nakajima, Teruyuki

    2016-11-01

    The amount of (137)Cs released by the Fukushima Dai-ichi Nuclear Power Plant accident of 11 March 2011 was inversely estimated by integrating an atmospheric dispersion model, an a priori source term, and map of deposition recorded by aircraft. An a posteriori source term refined finer (hourly) variations comparing with the a priori term, and estimated (137)Cs released 11 March to 2 April to be 8.12 PBq. Although time series of the a posteriori source term was generally similar to those of the a priori source term, notable modifications were found in the periods when the a posteriori source term was well-constrained by the observations. Spatial pattern of (137)Cs deposition with the a posteriori source term showed better agreement with the (137)Cs deposition monitored by aircraft. The a posteriori source term increased (137)Cs deposition in the Naka-dori region (the central part of Fukushima Prefecture) by 32.9%, and considerably improved the underestimated a priori (137)Cs deposition. Observed values of deposition measured at 16 stations and surface atmospheric concentrations collected on a filter tape of suspended particulate matter were used for validation of the a posteriori results. A great improvement was found in surface atmospheric concentration on 15 March; the a posteriori source term reduced root mean square error, normalized mean error, and normalized mean bias by 13.4, 22.3, and 92.0% for the hourly values, respectively. However, limited improvements were observed in some periods and areas due to the difficulty in simulating accurate wind fields and the lack of the observational constraints.

  4. Ecological Risk Assessment Framework for Low-Altitude Overflights by Fixed-Wing and Rotary-Wing Military Aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Efroymson, R.A.

    2001-01-12

    This is a companion report to the risk assessment framework proposed by Suter et al. (1998): ''A Framework for Assessment of Risks of Military Training and Testing to Natural Resources,'' hereafter referred to as the ''generic framework.'' The generic framework is an ecological risk assessment methodology for use in environmental assessments on Department of Defense (DoD) installations. In the generic framework, the ecological risk assessment framework of the US Environmental Protection Agency (EPA 1998) is modified for use in the context of (1) multiple and diverse stressors and activities at a military installation and (2) risks resulting from causal chains, e.g., effects on habitat that indirectly impact wildlife. Both modifications are important if the EPA framework is to be used on military installations. In order for the generic risk assessment framework to be useful to DoD environmental staff and contractors, the framework must be applied to specific training and testing activities. Three activity-specific ecological risk assessment frameworks have been written (1) to aid environmental staff in conducting risk assessments that involve these activities and (2) to guide staff in the development of analogous frameworks for other DoD activities. The three activities are: (1) low-altitude overflights by fixed-wing and rotary-wing aircraft (this volume), (2) firing at targets on land, and (3) ocean explosions. The activities were selected as priority training and testing activities by the advisory committee for this project.

  5. Application of slender wing benefits to military aircraft

    Science.gov (United States)

    Polhamus, E. C.

    1983-01-01

    A review is provided of aerodynamic research conducted at the Langley Research Center with respect to the application of slender wing benefits in the design of high-speed military aircraft, taking into account the supersonic performance and leading-edge vortex flow associated with very highly sweptback wings. The beginning of the development of modern classical swept wing jet aircraft is related to the German Me 262 project during World War II. In the U.S., a theoretical study conducted by Jones (1945) pointed out the advantages of the sweptback wing concept. Developments with respect to variable sweep wings are discussed, taking into account early research in 1946, a joint program of the U.S. with the United Kingdom, the tactical aircraft concept, and the important part which the Langley variable-sweep research program played in the development of the F-111, F-14, and B-1. Attention is also given to hybrid wings, vortex flow theory development, and examples of flow design technology.

  6. An Indispensable Ingredient: Flight Research and Aircraft Design

    Science.gov (United States)

    Gorn, Michael H.

    2003-01-01

    Flight research-the art of flying actual vehicles in the atmosphere in order to collect data about their behavior-has played a historic and decisive role in the design of aircraft. Naturally, wind tunnel experiments, computational fluid dynamics, and mathematical analyses all informed the judgments of the individuals who conceived of new aircraft. But flight research has offered moments of realization found in no other method. Engineer Dale Reed and research pilot Milt Thompson experienced one such epiphany on March 1, 1963, at the National Aeronautics and Space Administration s Dryden Flight Research Center in Edwards, California. On that date, Thompson sat in the cockpit of a small, simple, gumdrop-shaped aircraft known as the M2-F1, lashed by a long towline to a late-model Pontiac Catalina. As the Pontiac raced across Rogers Dry Lake, it eventually gained enough speed to make the M2-F1 airborne. Thompson braced himself for the world s first flight in a vehicle of its kind, called a lifting body because of its high lift-to-drag ratio. Reed later recounted what he saw:

  7. Experimental study of mountain lee—waves by means of satellite photographs and aircraft measurements

    OpenAIRE

    Cruette, Denise

    2011-01-01

    This paper is a summary of a Ph.D. Thesis1 which was a systematic study of the influence of various meteorological factors on the occurrence and characteristics of mountain waves, more specifically of lee-waves of great horizontal extent. The data used are, beside classical meteorological informations, that given by satellite pictures completed by quasi-simultaneous measurements from planes or gliders. The analysis of many satellite pictures received at the french station of Lannion (Brittany...

  8. Turboprop aircraft against terrorism: a SWOT analysis of turboprop aircraft in CAS operations

    Science.gov (United States)

    Yavuz, Murat; Akkas, Ali; Aslan, Yavuz

    2012-06-01

    Today, the threat perception is changing. Not only for countries but also for defence organisations like NATO, new threat perception is pointing terrorism. Many countries' air forces become responsible of fighting against terorism or Counter-Insurgency (COIN) Operations. Different from conventional warfare, alternative weapon or weapon systems are required for such operatioins. In counter-terrorism operations modern fighter jets are used as well as helicopters, subsonic jets, Unmanned Aircraft Systems (UAS), turboprop aircraft, baloons and similar platforms. Succes and efficiency of the use of these platforms can be determined by evaluating the conditions, the threats and the area together. Obviously, each platform has advantages and disadvantages for different cases. In this research, examples of turboprop aircraft usage against terrorism and with a more general approach, turboprop aircraft for Close Air Support (CAS) missions from all around the world are reviewed. In this effort, a closer look is taken at the countries using turboprop aircraft in CAS missions while observing the fields these aircraft are used in, type of operations, specifications of the aircraft, cost and the maintenance factors. Thus, an idea about the convenience of using these aircraft in such operations can be obtained. A SWOT analysis of turboprop aircraft in CAS operations is performed. This study shows that turboprop aircraft are suitable to be used in counter-terrorism and COIN operations in low threat environment and is cost benefical compared to jets.

  9. Aircraft type influence on contrail properties

    Directory of Open Access Journals (Sweden)

    P. Jeßberger

    2013-05-01

    Full Text Available The investigation of the impact of aircraft parameters on contrail properties helps to better understand the climate impact from aviation. Yet, in observations, it is a challenge to separate aircraft and meteorological influences on contrail formation. During the CONCERT campaign in November 2008, contrails from 3 Airbus passenger aircraft of type A319-111, A340-311 and A380-841 were probed at cruise under similar meteorological conditions with in-situ instruments on board the DLR research aircraft Falcon. Within the 2 min old contrails detected near ice saturation, we find similar effective diameters Deff (5.2–5.9 μm, but differences in particle number densities nice (162–235 cm−3 and in vertical contrail extensions (120–290 m, resulting in large differences in contrail optical depths τ (0.25–0.94. Hence larger aircraft produce optically thicker contrails. Based on the observations, we apply the EULAG-LCM model with explicit ice microphysics and in addition the Contrail and Cirrus Prediction model CoCiP to calculate the aircraft type impact on young contrails under identical meteorological conditions. The observed increase in τ for heavier aircraft is confirmed by the models, yet for generally smaller τ. An aircraft dependence of climate relevant contrail properties persists during contrail lifetime, adding importance to aircraft dependent model initialization. We finally derive an analytical relationship between contrail, aircraft and meteorological parameters. Near ice saturation, contrail width × τ scales linearly with fuel flow rate as confirmed by observations. For higher saturation ratios approximations from theory suggest a non-linear increase in the form (RHI–12/3. Summarized our combined results could help to more accurately assess the climate impact from aviation using an aircraft dependent contrail parameterization.

  10. Power Management Strategy by Enhancing the Mission Profile Configuration of Solar-Powered Aircraft

    Directory of Open Access Journals (Sweden)

    Parvathy Rajendran

    2016-01-01

    Full Text Available Solar energy offers solar-powered unmanned aerial vehicle (UAV the possibility of unlimited endurance. Some researchers have developed techniques to achieve perpetual flight by maximizing the power from the sun and by flying in accordance with its azimuth angles. However, flying in a path that follows the sun consumes more energy to sustain level flight. This study optimizes the overall power ratio by adopting the mission profile configuration of optimal solar energy exploitation. Extensive simulation is conducted to optimize and restructure the mission profile phases of UAV and to determine the optimal phase definition of the start, ascent, and descent periods, thereby maximizing the energy from the sun. In addition, a vertical cylindrical flight trajectory instead of maximizing the solar inclination angle has been adopted. This approach improves the net power ratio by 30.84% compared with other techniques. As a result, the battery weight may be massively reduced by 75.23%. In conclusion, the proposed mission profile configuration with the optimal power ratio of the trajectory of the path planning effectively prolongs UAV operation.

  11. 76 FR 45011 - Control of Air Pollution From Aircraft and Aircraft Engines; Proposed Emission Standards and Test...

    Science.gov (United States)

    2011-07-27

    ... procedures. EPA actively participated in the United Nation's International Civil Aviation Organization (ICAO... Regulation of Aircraft Engine Emissions E. Brief History of ICAO Regulation of Aircraft Engine Emissions II... under consideration by the United Nation's International Civil Aviation Organization (ICAO)....

  12. 14 CFR 119.53 - Wet leasing of aircraft and other arrangements for transportation by air.

    Science.gov (United States)

    2010-01-01

    ... wet lease, the Administrator determines which party to the agreement has operational control of the... otherwise authorized by the Administrator, prior to conducting operations involving a wet lease, each... shall provide the Administrator with a copy of the wet lease to be executed which would lease...

  13. 14 CFR 91.209 - Aircraft lights.

    Science.gov (United States)

    2010-01-01

    ...; or (iii) is in an area that is marked by obstruction lights; (3) Anchor an aircraft unless the aircraft— (i) Has lighted anchor lights; or (ii) Is in an area where anchor lights are not required on vessels; or (b) Operate an aircraft that is equipped with an anticollision light system, unless it...

  14. Maintenance of air worthiness of aircrafts

    Directory of Open Access Journals (Sweden)

    В. А. Горячев

    2000-09-01

    Full Text Available Described are modem conditions of operation of Russian civil aviation, state of aircraft stock, the main principles of maintaining air worthiness of airplanes and helicopters. Considered is a stage by stage prolongation of the service life of each specimen of aircraft with certification being obligatory

  15. Pursing Contamination Detection on Aircraft CFRP Surfaces By Artificial Olfaction Techniques

    Science.gov (United States)

    De Vito, Saverio; Massera, Ettore; Fattoruso, Grazia; Miglietta, Maria Lucia; Di Francia, Girolamo

    2011-09-01

    Carbon Fiber Reinforced Polymer (CFRP) structures can be easily bonded via adhesive assembly procedures but their cleanliness is of fundamental importance to ensure the strength of the adhesive bonding. Actually, surface contamination by several aeronautics fluids eventually results in weak or kissing bonds. The goal of our research work is to investigate solid state chemical sensors and artificial olfaction techniques (AO) for the detection of CFRP surface contamination by aeronautic fluids. This result will allow the implementation of an instrumental NDT procedure for CFRP surface cleanliness assessment prior to bonding. Herein, results of our first experimental setup, based on the use of an array of polymer sensors for the detection of aeronautic fluids contamination, are presented.

  16. Nondestructive damage characterization of complex aircraft structures by inverse methods: Advances in multiscale models

    Science.gov (United States)

    Murphy, R. Kim; Sabbagh, Harold A.; Sabbagh, Elias H.; Zhou, Liming; Bernacchi, William; Aldrin, John C.; Forsyth, David; Lindgren, Eric

    2016-02-01

    The use of coupled integral equations and anomalous currents allows us to efficiently remove `background effects' in either forward or inverse modeling. This is especially true when computing the change in impedance due to a small flaw in the presence of a larger background anomaly. It is more accurate than simply computing the response with and without the flaw and then subtracting the two nearly equal values to obtain the small difference due to the flaw. The problem that we address in this paper involves a 'SplitD' probe that includes complex, noncircular coils, as well as ferrite cores, inserted within a bolt hole, and exciting both the bolt hole and an adjacent flaw. This introduces three coupled anomalies, each with its on 'scale.' The largest, of course, is the bolt hole, followed (generally) by the probe, and then the flaw. The overall system is represented mathematically by three coupled volume-integral equations. We describe the development of the model and its code, which is a part of the general eddy-current modeling code, VIC-3D®. We present initial validation results, as well as a number of model computations with flaws located at various places within the bolt hole.

  17. Speeding up Transportation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ 2007 was an excellent year for the transportation industry, marked by high speed railway transportation, development of the national expressway network and launch of the Chang'e lunar probe satellite.

  18. F-8 digital fly-by-wire aircraft analytic redundancy management flight test experience

    Science.gov (United States)

    Deckert, J. C.

    1981-01-01

    The formulation and flight test results of an algorithm to detect and isolate the first failure of any one of twelve duplex control sensors being monitored are described. The technique uses like sensor output differences for fault detection while relying upon analytic redundancy relationships among unlike quantities to isolate the faulty sensor. The fault isolation logic utilizes the modified sequential probability ratio test, which explicitly accommodates the inevitable irreducible low frequency errors present in the analytic redundancy residuals. In addition, the algorithm uses sensor output selftest, which takes advantage of the duplex sensor structure by immediately removing a highly erratic sensor from control calculations and analytic redundancy relationships while awaiting a definitive fault isolation decision via analytic redundancy.

  19. Speed Control of Induction Motor Using PLC and SCADA System

    Directory of Open Access Journals (Sweden)

    Ayman Seksak Elsaid,

    2016-01-01

    Full Text Available Automation or automatic control is the use of various control systems for operating equipment such as machinery, processes in factories, boilers and heat-treating ovens, switching in telephone networks, steering and stabilization of ships, aircraft and other applications with minimal or reduced human intervention. Some processes have been completely automated. The motor speed is controlled via the driver as an open loop control. To make a more precise closed loop control of motor speed we will use a tachometer to measure the speed and feed it back to the PLC, which compares to the desired value and take a control action, then the signal is transferred to the motor – via driver – to increase / decrease the speed. We will measure the speed of the motor using an incremental rotary encoder by adjusting parameters (PLC, driver and also we need to reduce the overall cost of the system. Our control system will be held using the available Siemens PLC. In addition, we will monitor motor parameters via SCADA system.

  20. Aircraft Low Altitude Wind Shear Detection and Warning System.

    Science.gov (United States)

    Sinclair, Peter C.; Kuhn, Peter M.

    1991-01-01

    There is now considerable evidence to substantiate the causal relationship between low altitude wind shear (LAWS) and the recent increase in low-altitude aircraft accidents. The National Research Council has found that for the period 1964 to 1982, LAWS was involved in nearly all the weather-related air carrier fatalities. However, at present, there is no acceptable method, technique, or hardware system that provides the necessary safety margins, for spatial and timely detection of LAWS from an aircraft during the critical phases of landing and takeoff. The Federal Aviation Administration (FAA) has addressed this matter and supports the development of an airborne system for detecting hazardous LAWS with at least a one minute warning of the potential hazard to the pilot. One of the purposes of this paper is to show from some of our preliminary flight measurement research that a forward looking infrared radiometer (FLIR) system can be used to successfully detect the cool downdraft of downbursts [microbursts/macrobursts (MB)] and thunderstorm gust front outflows that are responsible for most of the LAWS events. The FLIR system provides a much greater safety margin for the pilot than that provided by reactive designs such as inertial-air speed systems that require the actual penetration of the MB before a pilot warning can be initiated. Our preliminary results indicate that an advanced airborne FLIR system could provide the pilot with remote indication of MB threat, location, movement, and predicted MB hazards along the flight path ahead of the aircraft.In a proof-of-concept experiment, we have flight tested a prototype FLIR system (nonscanning, fixed range) near and within Colorado MBs with excellent detectability. The results show that a minimum warning time of one-four minutes (5×10 km), depending on aircraft speed, is available to the pilot prior to a MB encounter. Analysis of the flight data with respect to a modified `hazard index' indicates the severe hazard