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. Speed stress and the aircraft pilot

    Directory of Open Access Journals (Sweden)

    W.T.V. Adiseshiah

    1958-07-01

    Full Text Available When the human component in a man-machine system of pushed beyond the limits of human capacity in grasping information presented to senses or in executing a series of actions correctly, a condition of "speed stress" may be said to occur. Conditions encountered by aircraft at high speeds, make a consideration of the forms of speed stress, and of the measures to alleviate them, extremely important.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Analysis and design technology for high-speed aircraft structures

    Science.gov (United States)

    Starnes, James H., Jr.; Camarda, Charles J.

    1992-01-01

    Recent high-speed aircraft structures research activities at NASA Langley Research Center are described. The following topics are covered: the development of analytical and numerical solutions to global and local thermal and structural problems, experimental verification of analysis methods, identification of failure mechanisms, and the incorporation of analysis methods into design and optimization strategies. The paper describes recent NASA Langley advances in analysis and design methods, structural and thermal concepts, and test methods.

  11. A study of instability in a miniature flying-wing aircraft in high-speed taxi

    Directory of Open Access Journals (Sweden)

    Song Lei

    2015-06-01

    Full Text Available This study investigates an instability that was observed during high-speed taxi tests of an experimental flying-wing aircraft. In order to resolve the reason of instability and probable solution of it, the instability was reproduced in simulations. An analysis revealed the unique stability characteristics of this aircraft. This aircraft has a rigid connection between the nose wheel steering mechanism and an electric servo, which is different from aircraft with a conventional tricycle landing gear system. The analysis based on simulation results suggests that there are two reasons for the instability. The first reason is a reversal of the lateral velocity of the nose wheel. The second reason is that the moment about the center of gravity created by the lateral friction force from the nose wheel is larger than that from the lateral friction force from the main wheels. These problems were corrected by changing the ground pitch angle. Simulations show that reducing the ground pitch angle can eliminate the instability in high-speed taxi.

  12. High Speed Civil Transport Aircraft Simulation: Reference-H Cycle 1, MATLAB Implementation

    Science.gov (United States)

    Sotack, Robert A.; Chowdhry, Rajiv S.; Buttrill, Carey S.

    1999-01-01

    The mathematical model and associated code to simulate a high speed civil transport aircraft - the Boeing Reference H configuration - are described. The simulation was constructed in support of advanced control law research. In addition to providing time histories of the dynamic response, the code includes the capabilities for calculating trim solutions and for generating linear models. The simulation relies on the nonlinear, six-degree-of-freedom equations which govern the motion of a rigid aircraft in atmospheric flight. The 1962 Standard Atmosphere Tables are used along with a turbulence model to simulate the Earth atmosphere. The aircraft model has three parts - an aerodynamic model, an engine model, and a mass model. These models use the data from the Boeing Reference H cycle 1 simulation data base. Models for the actuator dynamics, landing gear, and flight control system are not included in this aircraft model. Dynamic responses generated by the nonlinear simulation are presented and compared with results generated from alternate simulations at Boeing Commercial Aircraft Company and NASA Langley Research Center. Also, dynamic responses generated using linear models are presented and compared with dynamic responses generated using the nonlinear simulation.

  13. 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

  14. Aircraft

    Science.gov (United States)

    Hibbs, Bart D.; Lissaman, Peter B. S.; Morgan, Walter R.; Radkey, Robert L.

    1998-01-01

    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 gasses 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.

  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. 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...

  17. 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.

  18. 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.

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

    International Nuclear Information System (INIS)

    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. (letter)

  20. 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

  1. 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.

    1993-01-01

    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 January 1, 1992 to June 30, 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.

  2. 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.

  3. 1.5 μm lidar anemometer for true air speed, angle of sideslip, and angle of attack measurements on-board Piaggio P180 aircraft

    Science.gov (United States)

    Augere, B.; Besson, B.; Fleury, D.; Goular, D.; Planchat, C.; Valla, M.

    2016-05-01

    Lidar (light detection and ranging) is a well-established measurement method for the prediction of atmospheric motions through velocity measurements. Recent advances in 1.5 μm Lidars show that the technology is mature, offers great ease of use, and is reliable and compact. A 1.5 μm airborne Lidar appears to be a good candidate for airborne in-flight measurement systems. It allows measurements remotely, outside aircraft aerodynamic disturbance, and absolute air speed (no need for calibration) with great precision in all aircraft flight domains. In the framework of the EU AIM2 project, the ONERA task has consisted of developing and testing a 1.5 μm anemometer sensor for in-flight airspeed measurements. The objective of this work is to demonstrate that the 1.5 μm Lidar sensor can increase the quality of the data acquisition procedure for aircraft flight test certification. This article presents the 1.5 μm anemometer sensor dedicated to in-flight airspeed measurements and describes the flight tests performed successfully on-board the Piaggio P180 aircraft. Lidar air data have been graphically compared to the air data provided by the aircraft flight test instrumentation (FTI) in the reference frame of the Lidar sensor head. Very good agreement of true air speed (TAS) by a fraction of ms‑1, angle of sideslip (AOS), and angle of attack (AOA) by a fraction of degree were observed.

  4. 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.

  5. A comparison of aircraft tire skid with initial wheel 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...

  6. 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.

  7. 1.5 μm lidar anemometer for true air speed, angle of sideslip, and angle of attack measurements on-board Piaggio P180 aircraft

    International Nuclear Information System (INIS)

    Lidar (light detection and ranging) is a well-established measurement method for the prediction of atmospheric motions through velocity measurements. Recent advances in 1.5 μm Lidars show that the technology is mature, offers great ease of use, and is reliable and compact. A 1.5 μm airborne Lidar appears to be a good candidate for airborne in-flight measurement systems. It allows measurements remotely, outside aircraft aerodynamic disturbance, and absolute air speed (no need for calibration) with great precision in all aircraft flight domains. In the framework of the EU AIM2 project, the ONERA task has consisted of developing and testing a 1.5 μm anemometer sensor for in-flight airspeed measurements. The objective of this work is to demonstrate that the 1.5 μm Lidar sensor can increase the quality of the data acquisition procedure for aircraft flight test certification. This article presents the 1.5 μm anemometer sensor dedicated to in-flight airspeed measurements and describes the flight tests performed successfully on-board the Piaggio P180 aircraft. Lidar air data have been graphically compared to the air data provided by the aircraft flight test instrumentation (FTI) in the reference frame of the Lidar sensor head. Very good agreement of true air speed (TAS) by a fraction of ms−1, angle of sideslip (AOS), and angle of attack (AOA) by a fraction of degree were observed. (special issue article)

  8. Preliminary Design of the Low Speed Propulsion Air Intake of the LAPCAT-MR2 Aircraft

    Science.gov (United States)

    Meerts, C.; Steelant, J.; Hendrick, P.

    2011-08-01

    A supersonic air intake has been designed for the low speed propulsion system of the LAPCAT-MR2 aircraft. Development has been based on the XB-70 aircraft air intake which achieves extremely high performances over a wide operation range through the combined use of variable geometry and porous wall suction for boundary layer control. Design of the LAPCAT-MR2 intake has been operated through CFD simulations using DLR TAU-Code (perfect gas model - Menter SST turbulence model). First, a new boundary condition has been validated into the DLR TAU-Code (perfect gas model) for porous wall suction modelling. Standard test cases have shown surprisingly good agreement with both theoretical predictions and experimental results. Based upon this validation, XB-70 air intake performances have been assessed through CFD simulations over the subsonic, transonic and supersonic operation regions and compared to available flight data. A new simulation strategy was deployed avoiding numerical instabilities when initiating the flow in both transonic and supersonic operation modes. First, the flow must be initiated with a far field Mach number higher than the target flight Mach number. Additionally, the inlet backpressure may only be increased to its target value once the oblique shock pattern downstream the intake compression ramps is converged. Simulations using that strategy have shown excellent agreement with in-flight measurements for both total pressure recovery ratio and variable geometry schedule prediction. The demarcation between stable and unstable operation could be well reproduced. Finally, a modified version of the XB-70 air intake has been integrated in the elliptical intake on the LAPCAT vehicle. Operation of this intake in the LAPCAT-MR2 environment is under evaluation using the same simulation strategy as the one developed for the XB-70. Performances are assessed at several key operation points to assess viability of this design. This information will allow in a next

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

    Science.gov (United States)

    Weigel, R.; Spichtinger, P.; Mahnke, C.; Klingebiel, M.; Afchine, A.; Petzold, A.; Krämer, M.; Costa, A.; Molleker, S.; Jurkat, T.; Minikin, A.; Borrmann, S.

    2015-12-01

    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 for 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 particle penetration speed through the instruments' detection area equals 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 each underwing probe 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 260 m s-1. From HALO data it is found that ξ does not significantly vary between the different deployed instruments. Thus, for the current HALO underwing probe configuration a parameterisation of

  10. 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.

  11. Monitoring Aircraft Motion at Airports by LIDAR

    Science.gov (United States)

    Toth, C.; Jozkow, G.; Koppanyi, Z.; Young, S.; Grejner-Brzezinska, D.

    2016-06-01

    Improving sensor performance, combined with better affordability, provides better object space observability, resulting in new applications. Remote sensing systems are primarily concerned with acquiring data of the static components of our environment, such as the topographic surface of the earth, transportation infrastructure, city models, etc. Observing the dynamic component of the object space is still rather rare in the geospatial application field; vehicle extraction and traffic flow monitoring are a few examples of using remote sensing to detect and model moving objects. Deploying a network of inexpensive LiDAR sensors along taxiways and runways can provide both geometrically and temporally rich geospatial data that aircraft body can be extracted from the point cloud, and then, based on consecutive point clouds motion parameters can be estimated. Acquiring accurate aircraft trajectory data is essential to improve aviation safety at airports. This paper reports about the initial experiences obtained by using a network of four Velodyne VLP- 16 sensors to acquire data along a runway segment.

  12. 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

  13. 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.

  14. Movement speed is biased by prior experience

    Science.gov (United States)

    Yousif, Nada; Greenwood, Richard; Rothwell, John C.; Diedrichsen, Jörn

    2013-01-01

    How does the motor system choose the speed for any given movement? Many current models assume a process that finds the optimal balance between the costs of moving fast and the rewards of achieving the goal. Here, we show that such models also need to take into account a prior representation of preferred movement speed, which can be changed by prolonged practice. In a time-constrained reaching task, human participants made 25-cm reaching movements within 300, 500, 700, or 900 ms. They were then trained for 3 days to execute the movement at either the slowest (900-ms) or fastest (300-ms) speed. When retested on the 4th day, movements executed under all four time constraints were biased toward the speed of the trained movement. In addition, trial-to-trial variation in speed of the trained movement was significantly reduced. These findings are indicative of a use-dependent mechanism that biases the selection of speed. Reduced speed variability was also associated with reduced errors in movement amplitude for the fast training group, which generalized nearly fully to a new movement direction. In contrast, changes in perpendicular error were specific to the trained direction. In sum, our results suggest the existence of a relatively stable but modifiable prior of preferred movement speed that influences the choice of movement speed under a range of task constraints. PMID:24133220

  15. 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.

  16. 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.

  17. 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...

  18. Air-sampling inlet contamination by aircraft emissions on the NASA CV-990 aircraft

    Science.gov (United States)

    Condon, E. P.; Vedder, J. F.

    1984-01-01

    Results of an experimental investigation of the contamination of air sampling inlets by aircraft emissions from the NASA CV-990 research aircraft are presented. This four-engine jet aircraft is a NASA facility used for many different atmospheric and meteorological experiments, as well as for developing spacecraft instrumentation for remote measurements. Our investigations were performed to provide information on which to base the selection of sampling locations for a series of multi-instrument missions for measuring tropospheric trace gases. The major source of contamination is the exhaust from the jet engines, which generate many of the same gases that are of interest in atmospheric chemistry, as well as other gases that may interfere with sampling measurements. The engine exhaust contains these gases in mixing ratios many orders of magnitude greater than those that occur in the clean atmosphere which the missions seek to quantify. Pressurized samples of air were collected simultaneously from a scoop located forward of the engines to represent clean air and from other multiport scoops at various aft positions on the aircraft. The air samples were analyzed in the laboratory by gas chromatography for carbon monoxide, an abundant combustion by-product. Data are presented for various scoop locations under various flight conditions.

  19. 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.

  20. Design, testing and demonstration of a small unmanned aircraft system (sUAS) and payload for measuring wind speed and particulate matter in the atmospheric boundary layer

    Science.gov (United States)

    Riddell, Kevin Donald Alexander

    The atmospheric boundary layer (ABL) is the layer of air directly influenced by the Earth's surface and is the layer of the atmosphere most important to humans as this is the air we live in. Methods for measuring the properties of the ABL include three general approaches: satellite based, ground based and airborne. A major research challenge is that many contemporary methods provide a restricted spatial resolution or coverage of variations of ABL properties such as how wind speed varies across a landscape with complex topography. To enhance our capacity to measure the properties of the ABL, this thesis presents a new technique that involves a small unmanned aircraft system (sUAS) equipped with a customized payload for measuring wind speed and particulate matter. The research presented herein outlines two key phases in establishing the proof of concept of the payload and its integration on the sUAS: (1) design and testing and (2) field demonstration. The first project focuses on measuring wind speed, which has been measured with fixed wing sUASs in previous research. but not with a helicopter sUAS. The second project focuses on the measurement of particulate matter, which is a major air pollutant typically measured with ground-based sensors. Results from both proof of concept projects suggest that ABL research could benefit from the proposed techniques. .

  1. 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.

  2. 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.

  3. 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

  4. Fuel dispersal in high-speed aircraft/soil impact scenarios

    International Nuclear Information System (INIS)

    The objective of this study is to determine how the jet fuel contained in aircraft wing tanks disperses on impact with a soft terrain, i.e., soils, at high impact velocities. The approach used in this study is to combine experimental and numerical methods. Tests were conducted with an approximately 1/42 linear-scale mass-model of a 1/4 span section of a C-141 wing impacting a sand/clay mixture. The test results showed that within the uncertainty of the data, the percentage of incident liquid mass remaining in the crater is the same as that qualitatively described in earlier napalm bomb development studies. Namely, the percentage of fuel in the crater ranges from near zero for grazing impacts to 25%--50% for high angles of impact. To support a weapons system safety assessment (WSSA), the data from the current study have been reduced to correlations. The numerical model used in the current study is a unique coupling of a Smooth Particle Hydrodynamics (SPH) method with the transient dynamics finite element code PRONTO. Qualitatively, the splash, erosion, and soil compression phenomena are all numerically predicted. Quantitatively, the numerical method predicted a smaller crater cross section than was observed in the tests

  5. Fuel dispersal in high-speed aircraft/soil impact scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Tieszen, S.R.; Attaway, S.W. [Sandia National Labs., Albuquerque, NM (United States). Engineering Sciences Center

    1996-01-01

    The objective of this study is to determine how the jet fuel contained in aircraft wing tanks disperses on impact with a soft terrain, i.e., soils, at high impact velocities. The approach used in this study is to combine experimental and numerical methods. Tests were conducted with an approximately 1/42 linear-scale mass-model of a 1/4 span section of a C-141 wing impacting a sand/clay mixture. The test results showed that within the uncertainty of the data, the percentage of incident liquid mass remaining in the crater is the same as that qualitatively described in earlier napalm bomb development studies. Namely, the percentage of fuel in the crater ranges from near zero for grazing impacts to 25%--50% for high angles of impact. To support a weapons system safety assessment (WSSA), the data from the current study have been reduced to correlations. The numerical model used in the current study is a unique coupling of a Smooth Particle Hydrodynamics (SPH) method with the transient dynamics finite element code PRONTO. Qualitatively, the splash, erosion, and soil compression phenomena are all numerically predicted. Quantitatively, the numerical method predicted a smaller crater cross section than was observed in the tests.

  6. Program to compute the positions of the aircraft and of the aircraft sensor footprints

    Science.gov (United States)

    Paris, J. F. (Principal Investigator)

    1982-01-01

    The positions of the ground track of the aircraft and of the aircraft sensor footprints, in particular the metric camera and the radar scatterometer on the C-130 aircraft, are estimated by a program called ACTRK. The program uses the altitude, speed, and attitude informaton contained in the radar scatterometer data files to calculate the positions. The ACTRK program is documented.

  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. 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.

  9. 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

  10. Radiative forcing from particle emissions by future supersonic aircraft

    Directory of Open Access Journals (Sweden)

    G. Pitari

    2008-03-01

    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 modelling 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 O3 precursors changes due to aircraft emissions (NOx, HOx,Clx,Brx and 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 efficiency from

  11. 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

  12. High speed interference heating loads and pressure distributions resulting from elevon deflections. [shock wave interaction effects on hypersonic aircraft surfaces

    Science.gov (United States)

    Johnson, C. B.; Kaufman, L. G., III

    1979-01-01

    Effects of elevon-induced three-dimensional shock-wave turbulent boundary-layer interactions on hypersonic aircraft surfaces are analyzed. Detailed surface pressure and heating rate distributions obtained on wing-elevon-fuselage models representative of aft portions of hypersonic aircraft are compared with analytical and experimental results from other sources. Examples are presented that may be used to evaluate the adequacy of current theoretical methods for estimating the effects of three-dimensional shock-wave turbulent boundary-layer interactions on hypersonic aircraft surfaces.

  13. 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.

  14. 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.

  15. 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…

  16. 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.

  17. 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......) 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...

  18. Observations of the 2008 Kasatochi volcanic SO2 plume by CARIBIC aircraft DOAS and the GOME-2 satellite

    Directory of Open Access Journals (Sweden)

    F. Slemr

    2010-05-01

    Full Text Available The 2008 Kasatochi volcanic eruption emitted ≈1.5–2.5 Tg SO2 into the upper troposphere and lower stratosphere. Parts of the main volcanic plume (gases and particles reached central Europe a week after the eruption and were detected there by the CARIBIC (Civil Aircraft for Regular investigation of the Atmosphere based on an Instrument Container flying observatory. The plume was also observed by the GOME-2 satellite instrument, only a few hours after the CARIBIC aircraft had crossed the plume, thus giving a unique opportunity to compare results. Trajectories and local wind speeds are investigated in detail using the GOME-2 and CARIBIC observations for better comparison of the results from these two observational systems. A comparison of the satellite spatial pattern with the local observations of the wind speed and the trajectory model TRAJKS showed a slight discrepancy, which has to be considered for satellite validation. Hence, it appears that detailed analyses of wind speeds are required. Emitted and secondary particles, partly measured and sampled by the CARIBIC in situ instruments, affected the DOAS SO2 measurements, of both CARIBIC and GOME-2. Overall GOME-2 and the CARIBIC SO2 measurements agree very well. The major uncertainties remain the actual wind speed needed to properly correct for the advection of the plume between the different overpass times and effects of aerosols on DOAS retrievals. The good agreement can be seen as validation for both GOME-2 and CARIBIC DOAS observations.

  19. 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.

  20. 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.

  1. Specification and testing for power by wire aircraft

    Science.gov (United States)

    Hansen, Irving G.; Kenney, Barbara H.

    1993-08-01

    A power by wire aircraft is one in which all active functions other than propulsion are implemented electrically. Other nomenclature are 'all electric airplane,' or 'more electric airplane.' What is involved is the task of developing and certifying electrical equipment to replace existing hydraulics and pneumatics. When such functions, however, are primary flight controls which are implemented electrically, new requirements are imposed that were not anticipated by existing power system designs. Standards of particular impact are the requirements of ultra-high reliability, high peak transient bi-directional power flow, and immunity to electromagnetic interference and lightning. Not only must the electromagnetic immunity of the total system be verifiable, but box level tests and meaningful system models must be established to allow system evaluation. This paper discusses some of the problems, the system modifications involved, and early results in establishing wiring harness and interface susceptibility requirements.

  2. Specification and testing for power by wire aircraft

    Science.gov (United States)

    Hansen, Irving G.; Kenney, Barbara H.

    1993-01-01

    A power by wire aircraft is one in which all active functions other than propulsion are implemented electrically. Other nomenclature are 'all electric airplane,' or 'more electric airplane.' What is involved is the task of developing and certifying electrical equipment to replace existing hydraulics and pneumatics. When such functions, however, are primary flight controls which are implemented electrically, new requirements are imposed that were not anticipated by existing power system designs. Standards of particular impact are the requirements of ultra-high reliability, high peak transient bi-directional power flow, and immunity to electromagnetic interference and lightning. Not only must the electromagnetic immunity of the total system be verifiable, but box level tests and meaningful system models must be established to allow system evaluation. This paper discusses some of the problems, the system modifications involved, and early results in establishing wiring harness and interface susceptibility requirements.

  3. 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.

  4. 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...

  5. 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.

  6. 14 CFR 119.53 - Wet leasing of aircraft and other arrangements for transportation by air.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Wet leasing of aircraft and other arrangements for transportation by air. 119.53 Section 119.53 Aeronautics and Space FEDERAL AVIATION... Chapter § 119.53 Wet leasing of aircraft and other arrangements for transportation by air. (a)...

  7. 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.

  8. Experimental Assessment of the Emissions Control Potential of a Rich/Quench/Lean Combustor for High Speed Civil Transport Aircraft Engines

    Science.gov (United States)

    Rosfjord, T. J.; Padget, F. C.; Tacina, Robert R. (Technical Monitor)

    2001-01-01

    In support of Pratt & Whitney efforts to define the Rich burn/Quick mix/Lean burn (RQL) combustor for the High Speed Civil Transport (HSCT) aircraft engine, UTRC conducted a flametube-scale study of the RQL concept. Extensive combustor testing was performed at the Supersonic Cruise (SSC) condition of a HSCT engine cycle, Data obtained from probe traverses near the exit of the mixing section confirmed that the mixing section was the critical component in controlling combustor emissions. Circular-hole configurations, which produced rapidly-, highly-penetrating jets, were most effective in limiting NOx. The spatial profiles of NOx and CO at the mixer exit were not directly interpretable using a simple flow model based on jet penetration, and a greater understanding of the flow and chemical processes in this section are required to optimize it. Neither the rich-combustor equivalence ratio nor its residence time was a direct contributor to the exit NOx. Based on this study, it was also concluded that (1) While NOx formation in both the mixing section and the lean combustor contribute to the overall emission, the NOx formation in the mixing section dominates. The gas composition exiting the rich combustor can be reasonably represented by the equilibrium composition corresponding to the rich combustor operating condition. Negligible NOx exits the rich combustor. (2) At the SSC condition, the oxidation processes occurring in the mixing section consume 99 percent of the CO exiting the rich combustor. Soot formed in the rich combustor is also highly oxidized, with combustor exit SAE Smoke Number emissions control at SSC also performed better at part-power conditions. Data from mixer exit traverses reflected the expected mixing behavior for off-design jet to crossflow momentum-flux ratios. (4) Low power operating conditions require that the RQL combustor operate as a lean-lean combustor to achieve low CO and high efficiency. (5) A RQL combustor can achieve the emissions goal

  9. Nanocrystalline Ni-Co Alloy Synthesis by High Speed Electrodeposition

    OpenAIRE

    Jamaliah Idris; Chukwuekezie Christian; Eyu Gaius

    2013-01-01

    Electrodeposition of nanocrystals is economically and technologically viable production path for the synthesis of pure metals and alloys both in coatings and bulk form. The study presents nanocrystalline Ni-Co alloy synthesis by high speed electrodeposition. Nanocrystalline Ni-Co alloys coatings were prepared by direct current (DC) and deposited directly on steel and aluminum substrates without any pretreatment, using high speed electrodeposition method. The influence of the electrolysis par...

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. High-speed deformation of aluminum by cold rolling

    International Nuclear Information System (INIS)

    High-speed deformation of aluminum was carried out by use of a high-speed rolling machine, and the results were compared with those of impact compression. The rolled specimens were electro-polished and observed under an electron microscope. As compared with the microstructures observed in the impact compression specimens, the microstructures observed in the rolled specimens showed almost the same tendency as impact compression for vacancy loop formation, but a different tendency for dislocation cell formations. The difference in the results is explained by the variation in strain rate during deformation in rolling. The results indicate that in high-speed rolling, vacancies and dislocations are produced independently during different periods. Specifically, in the high-strain period, during which dislocations are not generated, deformation proceeds without dislocations

  15. 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,...

  16. Reduction of JT8D powered aircraft noise by engine refanning

    Science.gov (United States)

    Stitt, L. E.; Medeiros, A. A.

    1974-01-01

    The purpose of the Refan Program is to establish the technical feasibility of substantially reducing the noise levels of existing JT8D powered aircraft. This would be accomplished by retrofitting the existing fleet with quieter refan engines and new acoustically treated nacelles. No major technical problems exist that preclude the development and installation of refanned engines on aircraft currently powered by the JT8D engine. The refan concept is technically feasible and provides calculated noise reductions of from 7 to 8 EPNdB for the B727-200 aircraft and from 10 to 12 EPNdB for the DC-9-32 aircraft at the FAR Part 36 measuring stations. Corresponding reductions in the 90 EPNdB footprint area are estimated to vary from about 70 percent for the DC-9 to about 80 percent for the B727.

  17. Inattentional blindness is influenced by exposure time not motion speed.

    Science.gov (United States)

    Kreitz, Carina; Furley, Philip; Memmert, Daniel

    2016-01-01

    Inattentional blindness is a striking phenomenon in which a salient object within the visual field goes unnoticed because it is unexpected, and attention is focused elsewhere. Several attributes of the unexpected object, such as size and animacy, have been shown to influence the probability of inattentional blindness. At present it is unclear whether or how the speed of a moving unexpected object influences inattentional blindness. We demonstrated that inattentional blindness rates are considerably lower if the unexpected object moves more slowly, suggesting that it is the mere exposure time of the object rather than a higher saliency potentially induced by higher speed that determines the likelihood of its detection. Alternative explanations could be ruled out: The effect is not based on a pop-out effect arising from different motion speeds in relation to the primary-task stimuli (Experiment 2), nor is it based on a higher saliency of slow-moving unexpected objects (Experiment 3). PMID:26031845

  18. Aircraft optical cable plant: the physical layer for fly-by-light control networks

    Science.gov (United States)

    Weaver, Thomas L.

    1996-10-01

    A program was completed with joint industry and government funding to apply fiber optic technologies to aircraft. The technology offers many potential benefits. Among them are increased electromagnetic interference immunity and the possibility of reduced weight, increased reliability, and enlarged capability by redesigning architectures to use the large bandwidth of fiber optics. Those benefits can be realized if fiber optics meets the unique requirements of aircraft networks. Many independent efforts have been made in the development of the systems, known as cable plants, to link opto-electronic components. The FLASH program built on that work. Over the last two years, FLASH expanded on the cable plant efforts by building components based on a cohesive aircraft plant system concept. The concept was rooted in not just optical performance, but also cost, manufacturing, installation, maintenance, and support. To do that, the FLASH team evaluated requirements, delineated environmental and use conditions, designed, built, and tested components, such as cables, connectors, splices and backplanes for transport aircraft, tactical aircraft, and helicopters. In addition, the FLASH team developed installation and test methods, and support equipment for aircraft optical cable plants. The results of that design, development, and test effort are reported here.

  19. 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...

  20. 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.

  1. Estimation of Extreme Wind Speeds by Using Mixed Distributions

    Directory of Open Access Journals (Sweden)

    Escalante-Sandoval Carlos Agustín

    2013-04-01

    Full Text Available Structures are designed with the intention of safely withstanding ordinary and extreme wind loads over the entire intended economic lifetime. Due to the fact that extreme wind speeds are essentially random, appropriate statistical procedures needed to be developed in order design more accurately wind-sensitive structures. Five mixed extreme value distributions, with Gumbel, reverse Weibull and General Extreme Value components along with the Two Component Extreme Value distribution were used to model extreme wind speeds. The general procedure to estimate their parameters based on the maximum likelihood method is presented in the paper. A total of 45 sets, ranging from 9-year to 56-year, of largest annual wind speeds gathered from stations located in The Netherlands were fitted to mixed distributions. The best model was selected based on a goodness-of-fit test. The return levels were estimated and compared with those obtained by assuming the data arise from a single distribution. 87% of analyzed samples were better fitted with a mixed distribution. The best mixed models were the mixed reverse Weibull distribution and the mixture Gumbel-Reverse Weibull. Results suggest that it is very important to consider the mixed distributions as an additional mathematical tool when analyzing extreme wind speeds.

  2. How genealogies are affected by the speed of evolution

    OpenAIRE

    Brunet, Éric; Derrida, Bernard

    2011-01-01

    In a series of recent works it has been shown that a class of simple models of evolving populations under selection leads to genealogical trees whose statistics are given by the Bolthausen-Sznitman coalescent rather than by the well known Kingman coalescent in the case of neutral evolution. Here we show that when conditioning the genealogies on the speed of evolution, one finds a one parameter family of tree statistics which interpolates between the Bolthausen-Sznitman and Kingman's coalescen...

  3. 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.

  4. 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.

  5. Nanocrystalline Ni-Co Alloy Synthesis by High Speed Electrodeposition

    Directory of Open Access Journals (Sweden)

    Jamaliah Idris

    2013-01-01

    Full Text Available Electrodeposition of nanocrystals is economically and technologically viable production path for the synthesis of pure metals and alloys both in coatings and bulk form. The study presents nanocrystalline Ni-Co alloy synthesis by high speed electrodeposition. Nanocrystalline Ni-Co alloys coatings were prepared by direct current (DC and deposited directly on steel and aluminum substrates without any pretreatment, using high speed electrodeposition method. The influence of the electrolysis parameters, such as cathodic current density and temperature at constant pH, on electrodeposition and microstructure of Ni-Co alloys were examined. A homogeneous surface morphology was obtained at all current densities of the plated samples, and it was evident that the current density and temperature affect the coating thickness of Ni-Co alloy coatings.

  6. 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.

  7. Modal analysis by holographic interferometry of a turbine blade for aircraft engines

    Science.gov (United States)

    Caponero, Michele A.; De Angelis, Alberto; Filetti, V. R.; Gammella, S.

    1994-11-01

    Within the planning stage devoted to realize an innovative turbine for an aircraft engine, an experimental prototype has been made. Several measurements have been carried out to experimentally verify the expected structural and dynamic features of such a prototype. Expected properties were worked out by finite elements method, using the well-known Nastran software package. Natural frequencies and vibration modes of the designed prototype were computed assuming the turbine being in both `dynamic condition' (rotating turbine at running speed and temperature), and in `static condition' (still turbine at room temperature). We present the experimental modal analysis carried out by time average holographic interferometry, being the prototype in `static condition;' results show the modal behavior of the prototype. Experimental and computed modal features are compared to evaluate the reliability of the finite elements model of the turbine used for computation by the Nastran package; reliability of the finite elements model must be checked to validate results computed assuming the turbine blade is in hostile environments, such as `dynamic condition,' which could hardly be tested by experimental measurements. A piezoelectric transducer was used to excite the turbine blade by sine variable pressure. To better estimate the natural vibration modes, two holographic interferograms have been made for each identified natural frequency, being the sensitivity vector directions of the two interferograms perpendicular to each other. The first ten lower natural frequencies and vibration modes of the blade have been analyzed; experimental and computed results are compared and discussed. Experimental and computed values of natural frequencies are in good agrement between each other. Several differences are present between experimental and computed modal patterns; a possible cause of such discrepancies is identified in wrong structural constraints imposed at nodes of the finite elements

  8. 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.

  9. 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.

  10. 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.

  11. Combined Effect of Aircraft Noise and Pollutant Emissions by using ANN Model to Determine Healthy Risk Level

    OpenAIRE

    SETIA KURNIAWAN, Jermanto; KATILI, Irwan; MOERSIDIK, Setyo Sarwanto; Khardi, Salah

    2013-01-01

    Aircraft noise and pollutant emissions are an important part of the sources of pollution around airport that directly or indirectly will affect harmful to human health and ecosystems. The effects of aircraft noise and emissions on the populations around airport are deal with annoying and sometimes dangerous. In order to address this issue, the research propose an integrating model of aircraft noise and pollutant emissions by combining effects of both noise and pollutant emissions using Artifi...

  12. 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.

  13. 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

  14. 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...

  15. Modeling Disk Cracks in Rotors by Utilizing Speed Dependent Eccentricity

    Science.gov (United States)

    Gyekenyesi, Andrew L.; Sawicki, Jerzy T.; Haase, Wayne C.

    2010-03-01

    This paper discusses the feasibility of vibration-based structural health monitoring for detecting disk cracks in rotor systems. The approach of interest assumes that a crack located on a rotating disk causes a minute change in the system’s center of mass due to the centrifugal force induced opening of the crack. The center of mass shift is expected to reveal itself in the vibration vector (i.e., whirl response; plotted as amplitude and phase versus speed) gathered during a spin-up and/or spin-down test. Here, analysis is accomplished by modeling a Jeffcott rotor that is characterized by analytical, numerical, and experimental data. The model, which has speed dependent eccentricity, is employed in order to better understand the sensitivity of the approach. For the experimental set-up emulated here (i.e., a single disk located mid-span on a flexible shaft), it appears that a rather sizable flaw in the form of a through-thickness notch could be detected by monitoring the damage-induced shift in center of mass. Although, identifying actual disk cracks in complex “real world” environments, where noncritical crack lengths are small and excessive mechanical and/or electrical noise are present, would prove to be rather challenging. Further research is needed in this regard.

  16. 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

  17. 75 FR 39795 - Airworthiness Directives; Aircraft Industries a.s. (Type Certificate G60EU Previously Held by...

    Science.gov (United States)

    2010-07-13

    ... new AD: 2010-14-15 Aircraft Industries a.s. (Type Certificate G60EU Previously Held by LETECK Z VODY a...-031-AD; Amendment 39-16360; AD 2010-14-15] RIN 2120-AA64 Airworthiness Directives; Aircraft Industries a.s. (Type Certificate G60EU Previously Held by LETECK Z VODY a.s. and LET Aeronautical Works)...

  18. 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.

  19. 75 FR 52250 - Airworthiness Directives; Aircraft Industries a.s. (Type Certificate G24EU Previously Held by...

    Science.gov (United States)

    2010-08-25

    ... adding the following new AD: 2010-18-05 Aircraft Industries a.s. (Type Certificate G24EU Previously Held...-042-AD; Amendment 39-16418; AD 2010-18-05] RIN 2120-AA64 Airworthiness Directives; Aircraft Industries a.s. (Type Certificate G24EU Previously Held by LETECK Z VODY a.s. and LET Aeronautical Works)...

  20. 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.

  1. 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.

  2. 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.

  3. 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. PMID:27428866

  4. Vision assisted aircraft lateral navigation

    Science.gov (United States)

    Mohideen, Mohamed Ibrahim; Ramegowda, Dinesh; Seiler, Peter

    2013-05-01

    Surface operation is currently one of the least technologically equipped phases of aircraft operation. The increased air traffic congestion necessitates more aircraft operations in degraded weather and at night. The traditional surface procedures worked well in most cases as airport surfaces have not been congested and airport layouts were less complex. Despite the best efforts of FAA and other safety agencies, runway incursions continue to occur frequently due to incorrect surface operation. Several studies conducted by FAA suggest that pilot induced error contributes significantly to runway incursions. Further, the report attributes pilot's lack of situational awareness - local (e.g., minimizing lateral deviation), global (e.g., traffic in the vicinity) and route (e.g., distance to next turn) - to the problem. An Enhanced Vision System (EVS) is one concept that is being considered to resolve these issues. These systems use on-board sensors to provide situational awareness under poor visibility conditions. In this paper, we propose the use of an Image processing based system to estimate the aircraft position and orientation relative to taxiway markings to use as lateral guidance aid. We estimate aircraft yaw angle and lateral offset from slope of the taxiway centerline and horizontal position of vanishing line. Unlike automotive applications, several cues such as aircraft maneuvers along assigned route with minimal deviations, clear ground markings, even taxiway surface, limited aircraft speed are available and enable us to implement significant algorithm optimizations. We present experimental results to show high precision navigation accuracy with sensitivity analysis with respect to camera mount, optics, and image processing error.

  5. 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。

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

    International Nuclear Information System (INIS)

    It is shown that 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 雷诺数对大型客机低速气动特性影响的试验研究%Experimental Investigation on Effect of Reynolds Number on Aerodynamic Characteristics at Low Speed for Large Civil Aircraft

    Institute of Scientific and Technical Information of China (English)

    巴玉龙; 白峰

    2016-01-01

    在哈尔滨气动院FL-9增压风洞进行了某大型客机低速高雷诺数半模测力测压风洞试验,来流马赫数为0.2,增压范围为1~4个大气压。基于模型机翼平均气动弦长的雷诺数从2.9×106到11×106。以此为基础主要分析了雷诺数对机翼纵向气动力特性的影响,结果发现雷诺数对升力线斜率、最大升力系数、失速攻角和失速特性都有影响。相对于增升装置打开后的高升力构型,雷诺数对巡航构型的影响更明显。%Aerodynamic characteristics for a large civil aircraft are experimentally investigated at FL-9 low speed pressurized wind tunnel, focusing on the effect of Reynolds Number. The flow Mach number of 0. 2 and the pres-sure range of 1~4 atmospheric pressure are adopted in this test. The Reynolds number based on the model mean aerodynamic chord and free-stream velocity is from 2. 9 ×106 to 11 ×106 . Longitudinal aerodynamic characteristics of the wing are mainly analyzed. The experimental results show that the lift curve gradient, the maximum lift coeffi-cient and the stalling angle of attack are all affected by Reynolds Number . Compared to the high lift configurations, the effect of Reynolds number on cruise configuration is more obvious.

  14. Determination of standards for transportation of radioactive material by aircrafts

    International Nuclear Information System (INIS)

    The notification is defined under the provisions of the regulations for execution of the aviation law. Terms of exclusive loading and container are explained. Transportable radioactive materials hereunder exclude naturally igniting fluid materials, substances necessary to be contained in vessels which filtrate interior gas with filters or refrigerate contents with cooling devices, etc., or BM loads necessary to be continuously ventilated. Radioactive materials to be conveyed as radioactive loads and L loads are prescribed with tables attached. Technical standards for radioactive loads are stipulated for L, A, BM and BU loads respectively. Confirmation of safety of radioactive loads may be made by examiniation of documents prepared by persons acknowledged proper by the Minister of Transportation. Radioactive materials are uranium 233 and 235, plutonium 238, 239 and 241, their compounds and those materials which include one or more than two of such substances. Materials whose quantities or quantities of components are less than 15 grams and natural or depleted uranium are excluded. The maximum doses of containers with radioactive loads shall not exceed for an hour 200 mili-rem on the surface and 10 mili-rem at a distance of 1 meter from the surface. Confirmation of safety of transport, method of loading, prevention of criticality, restriction of mixed shipment, transport index, signals and others are provided for in detail. (Okada, K.)

  15. 14 CFR 39.23 - May I fly my aircraft to a repair facility to do the work required by an airworthiness directive?

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false May I fly my aircraft to a repair facility... May I fly my aircraft to a repair facility to do the work required by an airworthiness directive? Yes... allow them to fly their aircraft to a repair facility to do the work required by an...

  16. A new measurement method for separating airborne and structureborne noise radiated by aircraft type panels

    Science.gov (United States)

    Mcgary, M. C.

    1982-01-01

    The theoretical basis for and experimental validation of a measurement method for separating airborne and structure borne noise radiated by aircraft type panels are presented. An extension of the two microphone, cross spectral, acoustic intensity method combined with existing theory of sound radiation of thin shell structures of various designs, is restricted to the frequency range below the coincidence frequency of the structure. Consequently, the method lends itself to low frequency noise problems such as propeller harmonics. Both an aluminum sheet and two built up aircraft panel designs (two aluminum panels with frames and stringers) with and without added damping were measured. Results indicate that the method is quick, reliable, inexpensive, and can be applied to thin shell structures of various designs.

  17. 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

  18. Monitoring and forecasting of great radiation hazards for spacecraft and aircrafts by online cosmic ray data

    Directory of Open Access Journals (Sweden)

    L. I. Dorman

    2005-11-01

    Full Text Available We show that an exact forecast of great radiation hazard in space, in the magnetosphere, in the atmosphere and on the ground can be made by using high-energy particles (few GeV/nucleon and higher whose transportation from the Sun is characterized by a much bigger diffusion coefficient than for small and middle energy particles. Therefore, high energy particles come from the Sun much earlier (8-20 min after acceleration and escaping into solar wind than the main part of smaller energy particles (more than 30-60 min later, causing radiation hazard for electronics and personal health, as well as spacecraft and aircrafts. We describe here principles of an automatic set of programs that begin with "FEP-Search", used to determine the beginning of a large FEP event. After a positive signal from "FEP-Search", the following programs start working: "FEP-Research/Spectrum", and then "FEP-Research/Time of Ejection", "FEP-Research /Source" and "FEP-Research/Diffusion", which online determine properties of FEP generation and propagation. On the basis of the obtained information, the next set of programs immediately start to work: "FEP-Forecasting/Spacecrafts", "FEP-Forecasting/Aircrafts", "FEP-Forecasting/Ground", which determine the expected differential and integral fluxes and total fluency for spacecraft on different orbits, aircrafts on different airlines, and on the ground, depending on altitude and cutoff rigidity. If the level of radiation hazard is expected to be dangerous for high level technology or/and personal health, the following programs will be used "FEP-Alert/Spacecrafts", "FEP-Alert/ Aircrafts", "FEP-Alert/Ground".

  19. Cosmic radiation and airline pilots. Exposure patterns of Norwegian pilots flying aircraft not used by SAS

    Energy Technology Data Exchange (ETDEWEB)

    Tveten, U.

    1997-05-01

    The work which is presented in this report is part of a Norwegian epidemiological project, carried out in cooperation between Institutt for Energiteknikk (IFE), the Norwegian Cancer Registry (NCR) and the Norwegian Radiation Protection Authority (NRPA). The project has been partially financed by the Norwegian Research Council. Originating from the Norwegian project, a number of similar projects have been started or are in the planning stage in a number of European countries. The present report lays the ground for estimation of individual exposure histories to cosmic radiation of pilots flying a great diversity of different aircrafts. Aircrafts that appear in the time-tables of the Scandinavian Airline System (SAS) have been treated in an earlier report. The results presented in this report (radiation doserates for the different types of aircrafts in the different years) will, in a later stage of the project be utilized to estimate the individual radiation exposure histories. The major sources of information used as basis for the work in this report is information provided by several active pilots, members of the Pilots Associations, along with calculations performed using US Federal Aviation Administration`s computer code CARI-3N. 2 refs.

  20. Cosmic radiation and airline pilots. Exposure patterns of Norwegian pilots flying aircraft not used by SAS

    International Nuclear Information System (INIS)

    The work which is presented in this report is part of a Norwegian epidemiological project, carried out in cooperation between Institutt for Energiteknikk (IFE), the Norwegian Cancer Registry (NCR) and the Norwegian Radiation Protection Authority (NRPA). The project has been partially financed by the Norwegian Research Council. Originating from the Norwegian project, a number of similar projects have been started or are in the planning stage in a number of European countries. The present report lays the ground for estimation of individual exposure histories to cosmic radiation of pilots flying a great diversity of different aircrafts. Aircrafts that appear in the time-tables of the Scandinavian Airline System (SAS) have been treated in an earlier report. The results presented in this report (radiation doserates for the different types of aircrafts in the different years) will, in a later stage of the project be utilized to estimate the individual radiation exposure histories. The major sources of information used as basis for the work in this report is information provided by several active pilots, members of the Pilots Associations, along with calculations performed using US Federal Aviation Administration's computer code CARI-3N. 2 refs

  1. Sonic booms produced by US Air Force and US Navy aircraft: Measured data

    Science.gov (United States)

    Lee, R. A.; Downing, J. M.

    1991-01-01

    A sonic measurement program was conducted at Edwards Air Force Base. Sonic boom signatures, produced by F-4, F-14, F-15, F-16, F-18, F-111, SR-71, and T-38 aircraft, were obtained under the flight track and at various lateral sites which were located up to 18 miles off-track. Thirteen monitors developed by Det 1 AL/BBE were used to collect full sonic boom waveforms, and nine modified dosimeters were used to collect supplemental peak overpressures and the C-weighted Sound Exposure Levels (CSEL) for 43 near steady supersonic flights of the above United States Air Force and United States Navy aircraft. This report describes the measured database (BOOMFILE) that contains sonic boom signatures and overpressures, aircraft tracking, and local weather data. These measured data highlight the major influences on sonic boom propagation and generation. The data from this study show that a constant offset of 26 from the peak overpressure expressed in dB gives a good estimate of the CSEL of a sonic boom.

  2. 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.

  3. 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.

  4. 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...

  5. 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

  6. Effects of damping on the speed of increase and amplitude of limit cycle for an aircraft braking system subjected to mode-coupling instability

    OpenAIRE

    Chevillot, Fabrice; Sinou, Jean-Jacques; Hardouin, Nicolas; Jezequel, Louis

    2010-01-01

    International audience A nonlinear model of an aircraft braking system is presented and used to investigate the effects of damping on the stability in Chevillot et al. (Arch Appl Mech 78(12):949-963, 2008). It has been shown that the addition of damping into the equations of motion does not lead systematically to the stabilization of the system. In the case of a mode-coupling instability, there is indeed an optimal ratio between the modal damping coefficients of the two modes in coalescenc...

  7. 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.

  8. 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.)

  9. 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.

  10. 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.

  11. 19 CFR 122.64 - Other aircraft.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Other aircraft. 122.64 Section 122.64 Customs... AIR COMMERCE REGULATIONS Clearance of Aircraft and Permission To Depart § 122.64 Other aircraft. Clearance or permission to depart shall be requested by the aircraft commander or agent for aircraft...

  12. Annual variations in sea surface wind speed around Japan observed by ASCAT

    Science.gov (United States)

    Takeyama, Y.; Shimada, S.; Ohsawa, T.; Kozai, K.; Kogaki, T.

    2015-12-01

    Sea surface wind speeds and these statistics can be applied for many marine industrial activities. For example, the averaged wind speed is crucial information for a site selection of an offshore wind farm. It has widely been recognized that a total amount of the offshore wind generation is strongly depended on the annual average wind speeds. A advanced scatterometer (ASCAT), which is a kind of scatterometer aboard METOP-A and B, has observed sea surface wind speeds at the height of 10 m above the sea surface approximately twice a day using active microwaves. The annual average wind speed can be calculated from the observed wind speed. For an actual use of the annual average wind speed, generalities and representativeness of the wind speed must be clarified. To investigate annual variations in sea surface wind speed around Japan (120°E to 165°E, 19°N to 49°N), the annual average wind speeds and these standard deviations are calculated from 5 years of ASCAT observations from 2010 through 2014. It is found that there are some sea areas where standard deviations are relatively higher than their surroundings. Annual average wind speed maps indicate that the high standard deviation is caused by strong winds from Eurasia in the winter of 2011 in part of North Pacific Ocean and Sea of Okhotsk. Additionally standard deviations for only winter are also higher than for summer in those sea areas. Therefore the strong wind speed in the winter of a particular year can easily affect to the annual average wind speed. Meanwhile off the coast of Niigata and Hokkaido, there are also higher standard deviation areas than their surroundings. Differences between monthly maximum wind speeds for the winter and minimum wind speeds for the summer in these areas are larger and the large differences seem to be a cause of the high standard deviations.

  13. Fly-by-light flight control system architectures for tactical military aircraft

    Science.gov (United States)

    Corrigan, Jack; Jones, Jack E.; Shaw, Brad

    1995-05-01

    Requirements for future advanced tactical aircraft identify the need for flight control system architectures that provide a higher degree of performance with regard to electromagnetic interference immunity, communication bus data rate, propulsion/utility subsystem integration, and affordability. Evolution of highly centralized, digital, fly-by-wire flight/propulsion/utility control system is achieved as modular functions are implemented and integrated by serial, digital, fiber optics communication links. These adaptable architectures allow the user to configure the fly-by-light system to meet unique safety requirements, system performance, and design to cost targets.

  14. 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

  15. Lightning effects on aircraft

    Science.gov (United States)

    1977-01-01

    Direct and indirect effects of lightning on aircraft were examined in relation to aircraft design. Specific trends in design leading to more frequent lightning strikes were individually investigated. These trends included the increasing use of miniaturized, solid state components in aircraft electronics and electric power systems. A second trend studied was the increasing use of reinforced plastics and other nonconducting materials in place of aluminum skins, a practice that reduces the electromagnetic shielding furnished by a conductive skin.

  16. 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.

  17. Aircraft optical cable plant program plan: the approach for the physical layer for fly-by-light control networks

    Science.gov (United States)

    Weaver, Thomas L.; Murdock, John K.

    1995-05-01

    A program was created with joint industry and government funding to apply fiber optic technologies to aircraft. The technology offers many potential benefits. Among them are increased electromagnetic interference immunity and the possibility of reduced weight, increased reliability, and enlarged capability by redesigning architectures to use the large bandwidth of fiber optics. Those benefits will only be realized if fiber optics meets the unique requirements of aircraft networks. Over the past two decades, considerable effort has been expended on applying photonic technologies to aircraft. Great successes have occurred in optoelectronic components development. In the development of these systems to link those components, known as the cable plant, progress has also been made, but only recently has it been organized in a coordinated, systems-oriented fashion. The FLASH program will expand on the nascent cable plant systems efforts by building upon recent work in individual components, and integrating that work into a cohesive aircraft cable plant. Therefore, the FLASH program will develop the low cost, reliable cables, connectors, splices, backplanes, manufacturing and installation methods, test methods, support equipment, and training systems needed to form a true optical cable plant for transport aircraft, tactical aircraft, and helicopters.

  18. Local damage to Ultra High Performance Concrete structures caused by an impact of aircraft engine missiles

    Energy Technology Data Exchange (ETDEWEB)

    Riedel, Werner [Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institute, Eckerstrasse 4, D-79104 Freiburg (Germany); Noeldgen, Markus, E-mail: mnoeldgen@schuessler-plan.d [Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institute, Eckerstrasse 4, D-79104 Freiburg (Germany); Schuessler-Plan Engineering Ltd., St.-Franziskus-Str. 148, D-40470 Duesseldorf (Germany); Strassburger, Elmar; Thoma, Klaus [Fraunhofer Institute for High-Speed Dynamics, Ernst-Mach-Institute, Eckerstrasse 4, D-79104 Freiburg (Germany); Fehling, Ekkehard [University of Kassel, Chair of Structural Concrete, Kurt-Wolters Str. 3, D-34109 Kassel (Germany)

    2010-10-15

    Research highlights: {yields} Experimental series on UHPC panels subjected to aircraft engine impact. {yields} Improved ballistic limit of fiber reinforced UHPC in comparison to conventional R/C. {yields} Detailed investigation of failure mechanisms of fiber reinforced UHPC panel. - Abstract: The impact of an aircraft engine missile causes high stresses, deformations and a severe local damage to conventional reinforced concrete. As a consequence the design of R/C protective structural elements results in components with rather large dimensions. Fiber reinforced Ultra High Performance Concrete (UHPC) is a concrete based material which combines ultra high strength, high packing density and an improved ductility with a significantly increased energy dissipation capacity due to the addition of fiber reinforcement. With those attributes the material is potentially suitable for improved protective structural elements with a reduced need for material resources. The presented paper reports on an experimental series of scaled aircraft engine impact tests with reinforced UHPC panels. The investigations are focused on the material behavior and the damage intensity in comparison to conventional concrete. The fundamental work of is taken as reference for the evaluation of the results. The impactor model of a Phantom F4 GE-J79 engine developed and validated by Sugano et al. is used as defined in the original work. In order to achieve best comparability, the experimental configuration and method are adapted for the UHPC experiments. With 'penetration', 'scabbing' and 'perforation' all relevant damage modes defined in are investigated so that a full set of results are provided for a representative UHPC structural configuration.

  19. D-558-2 Aircraft on lakebed

    Science.gov (United States)

    1955-01-01

    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 to test airspeed calibrations and to research longitudinal and lateral stability and control

  20. Variable speed pumped storage system fed by large-scale cycloconverter

    Energy Technology Data Exchange (ETDEWEB)

    T, Taguchi. (The Tokyo Electric Power Co. Inc., Tokyo (Japan)); Mukai, K.; Yanagisawa, T.; Kanai, T. (Toshiba Corp., Tokyo (Japan))

    1992-01-01

    The world{prime}s first variable speed pumped storage system fed by large-scale cycloconverter was brought into operation at the Yagisawa power station Unit 2 of Tokyo Electric Power Co. in December, 1990. The present paper introduces an outline and operation results of this system. This remarkable system incorporates the latest large-scale, large-capacity power electronics technology, ultrahigh-speed digital control technology, and large-scale, large-capacity generator-motor technology. From the actual machine tests conducted at the Yagisawa power station, various functions of the variable speed pumped storage system were verified. The variable speed system enabled to regulate the input of the pump within the range of about 50 to 85MW. Additionally, in the turbine operation, vibration of the pump-turbine was improved by operating with the optimum rotating speed. Furthermore, the variable speed system did not cause unstable condition of power swing. 4 refs., 16 figs., 2 tabs.

  1. 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.

  2. 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.

  3. 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.

  4. Internal Flow Measurement of a Very Low Specific-Speed Centrifugal Pump by PIV

    OpenAIRE

    Choi, Y.-D.; Kurokawa, Junichi; Nishino, K; Matsui, J.; Imamura, H.

    2002-01-01

    As the performance characteristics of a very low specific-speed centrifugal pump are much different from those of a normal specific-speed pump, there is strong demand of full understanding for the internal flow of the very low specific-speed centrifugal pump in order to improve the pump performance. The purpose of this study is to establish a method of visualization by PIV for a very low specific-speed centrifugal pump and to make clear the internal flow characteristics of the pump. Test pump...

  5. 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.

  6. 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...

  7. Demonstration results of fly-by-light flight control system architectures for tactical military aircraft

    Science.gov (United States)

    Corrigan, Jack; Shaw, Brad; Jones, Jack E.

    1996-10-01

    Requirements for future advanced tactical aircraft identify the need for flight control system architectures that provide a higher degree of performance with regard to electromagnetic interference immunity, communication bus data rate, propulsion/utility subsystem integration, and affordability. Evolution for highly centralized, digital, fly-by-light flight/propulsion/utility control system is achieved as modular functions are implemented and integrated by serial digital fiberoptic communication links. These adaptable architectures allow the user to configure the fly- by-light system to meet unique safety requirements, system performance, and design-to-cost targets. This paper presents results of the open and closed loop system demonstrations of Fly-By-Light Advanced System Hardware architecture building blocks integrated with SAE AS-1773 communication bus at MDA.

  8. Auralization of novel aircraft configurations

    OpenAIRE

    Arntzen, M.; Bertsch, E.L.; Simons, D.G.

    2015-01-01

    A joint initiative of NLR, DLR, and TU Delft has been initiated to streamline the process of generating audible impressions of novel aircraft configurations. The integrated approach adds to the value of the individual tools and allows predicting the sound of future aircraft before they actually fly. Hence, an existing process for the aircraft design and system noise prediction at DLR has been upgraded to generate the required input data for an aircraft auralization framework developed by NLR ...

  9. Speed limits and enforcement : speed limits and enforcement by police supervision : objective and subjective risk of detection.

    NARCIS (Netherlands)

    Kraay, J.H. & Mattie, P.C.

    1973-01-01

    This brochure on speed limits and enforcement sets out two closely related studies. The first report is based on a literature study concerning studies of the effect of police supervision on the enforcement of speed limits. The second report sets out a framework of concepts based on the chance of det

  10. Modelling concentrations of volcanic ash encountered by aircraft in past eruptions

    Science.gov (United States)

    Witham, Claire; Webster, Helen; Hort, Matthew; Jones, Andrew; Thomson, David

    2012-03-01

    Prolonged disruption to aviation during the April-May 2010 eruption of Eyjafjallajökull, Iceland resulted in pressure to predict volcanic ash plume concentrations for the purpose of allowing aircraft to fly in regions with low ash contamination. Over the past few decades there have been a number of incidents where aircraft have encountered volcanic ash resulting in damage to the aircraft and loss of power to engines. Understanding the volcanic ash concentrations that these aircraft have encountered provides important input to determining a safe concentration limit. Aircraft encounters with six volcanic eruption plumes have been studied and ash concentrations predicted using the atmospheric dispersion model NAME. The eruptions considered are Galunggung 1982, Soputan 1985, Redoubt 1989, Pinatubo 1991, Hekla 2000 and Manam 2006. Uncertainties in the eruption source details (start time, stop time and eruption height) and in the aircraft encounter location and flight path are found to be major limitations in some cases. Errors in the driving meteorological data (which is often coarse in resolution for historic studies) and the lack of eruption plume dynamics (e.g. umbrella cloud representation) results in further uncertainties in the predicted ash concentrations. In most of the case studies, the dispersion modelling shows the presence of ash at the aircraft encounter location. Maximum ash concentrations in the vicinity of the aircraft are predicted to be at least 4000 μg m -3 although confidence in the estimated concentrations is low and uncertainties of orders of magnitude are shown to be possible.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Aircraft Noise

    Science.gov (United States)

    Michel, Ulf; Dobrzynski, Werner; Splettstoesser, Wolf; Delfs, Jan; Isermann, Ullrich; Obermeier, Frank

    Aircraft industry is exposed to increasing public pressure aiming at a continuing reduction of aircraft noise levels. This is necessary to both compensate for the detrimental effect on noise of the expected increase in air traffic and improve the quality of living in residential areas around airports.

  16. 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.

  17. 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.

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

    International Nuclear Information System (INIS)

    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.

  19. 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.

  20. Cross-tropopause transport by deep convective storms : model simulations and satellite/aircraft observations

    Science.gov (United States)

    Wang, P. K.

    2008-12-01

    More and more evidences have shown that deep convective storms play an important role in the transport of water vapor from the troposphere into the stratosphere. Such transport has been observed to occur not only in midlatitudes but in lower latitudes as well. Observational evidences include elongated storm overshooting top cirrus plumes in the presence of strong upper level wind shear and pancake clouds above storm clouds in weak shear environment as observed in satellite visible and infrared images. In addition, jumping cirrus phenomenon observed by aircraft and ground based photography corroborates with satellite observations to further confirm the deep convective transport. Simulations of deep convective storms using a cloud resolving model provide more details on the physics and dynamics of this mechanism and also suggest potential techniques of using satellite data to estimate the deep convective transport. All these will be reviewed and summarized in this paper.

  1. Noise simulation of aircraft engine fans by the boundary element method

    Science.gov (United States)

    Pyatunin, K. R.; Arkharova, N. V.; Remizov, A. E.

    2016-07-01

    Numerical simulation results of the civil aircraft engine fan stage noise in the far field are presented. Non-steady-state rotor-stator interaction is calculated the commercial software that solves the Navier-Stokes equations using differentturbulence models. Noise propagation to the far acoustic field is calculated by the boundary element method using acoustic Lighthill analogies without taking into account the mean current in the air inlet duct. The calculated sound pressure levels at points 50 m from the engine are presented, and the directional patterns of the acoustic radiation are shown. The use of the eddy resolving turbulence model to calculate rotor-stator interaction increases the accuracy in predicting fan stage noise.

  2. 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 .

  3. Effective density measurements of fresh particulate matter emitted by an aircraft engine

    Science.gov (United States)

    Abegglen, Manuel; Durdina, Lukas; Mensah, Amewu; Brem, Benjamin; Corbin, Joel; Rindlisbacher, Theo; Wang, Jing; Lohmann, Ulrike; Sierau, Berko

    2014-05-01

    Introduction Carbonaceous particulate matter (commonly referred to as soot), once emitted into the atmosphere affects the global radiation budget by absorbing and scattering solar radiation. Furthermore, it can alter the formation, lifetime and distribution of clouds by acting as cloud condensation nuclei (CCN) or ice nuclei (IN). The ability of soot particles to act as CCN and IN depends on their size, morphology and chemical composition. Soot particles are known to consist of spherical, primary particles that tend to arrange in chain-like structures. The structure of soot particles typically changes in the atmosphere when the particles are coated with secondary material, thus changing their radiative and cloud microphysical properties. Bond et al. (Journal of Geophysical Research, 2013: Bounding the Role of Black Carbon in the Climate System.) estimated the total industrial-era (1750 to 2005) climate forcing of black carbon to be 1.1 W/m2 ranging from the uncertainty bonds of 0.17 W/m2 to 2.1 W/m2. Facing the large uncertainty range, there is a need for a better characterization of soot particles abundant in the atmosphere. We provide experimental data on physical properties such as size, mass, density and morphology of freshly produced soot particles from a regularly used aircraft engine and from four laboratory generated soot types. This was done using a Differential Mobility Analyzer (DMA) and a Centrifugal Particle Mass Analyzer (CPMA), a relatively new instrument that records mass distributions of aerosol particles. Experimental Aircraft engine exhaust particles were collected and analysed during the Aviation Particle Regulatory Instrumentation Demonstration Experiments (A-PRIDE) campaigns in a test facility at the Zurich airport in November 2012 and August 2013. The engines were operated at different relative thrust levels spanning 7 % to 100 %. The sample was led into a heated line in order to prevent condensation of water and evolution of secondary

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 31 CFR 500.585 - Payments for services rendered by North Korea to United States aircraft authorized.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Payments for services rendered by North Korea to United States aircraft authorized. 500.585 Section 500.585 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) OFFICE OF FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY FOREIGN ASSETS CONTROL...

  9. 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.

  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. 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.

  12. 14 CFR 141.39 - Aircraft.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Aircraft. 141.39 Section 141.39 Aeronautics... CERTIFICATED AGENCIES PILOT SCHOOLS Personnel, Aircraft, and Facilities Requirements § 141.39 Aircraft. (a... certificate or provisional pilot school certificate must show that each aircraft used by the school for...

  13. 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.

  14. 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.

  15. Speeding up SAT solver by exploring CNF symmetries : Revisited

    CERN Document Server

    Ghosh, Arup Kumar

    2011-01-01

    Boolean Satisfiability solvers have gone through dramatic improvements in their performances and scalability over the last few years by considering symmetries. It has been shown that by using graph symmetries and generating symmetry breaking predicates (SBPs) it is possible to break symmetries in Conjunctive Normal Form (CNF). The SBPs cut down the search space to the nonsymmetric regions of the space without affecting the satisfiability of the CNF formula. The symmetry breaking predicates are created by representing the formula as a graph, finding the graph symmetries and using some symmetry extraction mechanism (Crawford et al.). Here in this paper we take one non-trivial CNF and explore its symmetries. Finally, we generate the SBPs and adding it to CNF we show how it helps to prune the search tree, so that SAT solver would take short time. Here we present the pruning procedure of the search tree from scratch, starting from the CNF and its graph representation. As we explore the whole mechanism by a non-tri...

  16. Using Fly-By-Wire Technology in Future Models of the UH-60 and Other Rotary Wing Aircraft

    Science.gov (United States)

    Solem, Courtney K.

    2011-01-01

    Several fixed-winged airplanes have successfully used fly-by-wire (FBW) technology for the last 40 years. This technology is now beginning to be incorporated into rotary wing aircraft. By using FBW technology, manufacturers are expecting to improve upon the weight, maintenance time and costs, handling and reliability of the aircraft. Before mass production of this new system begins in new models such as the UH-60MU, testing must be conducted to insure the safety of this technology as well as to reassure others it will be worth the time and money to make such a dramatic change to a perfectly functional machine. The RASCAL JUH-60A has been modified for these purposes. This Black Hawk helicopter has already been equipped with the FBW technology and can be configured as a near perfect representation of the UH-60MU. Because both machines have very similar qualities, the data collected from the RASCAL can be used to make future decisions about the UH-60MU. The U.S. Army AFDD Flight Project Office oversees all the design modifications for every hardware system used in the RASCAL aircraft. This project deals with specific designs and analyses of unique RASCAL aircraft subsystems and their modifications to conduct flight mechanics research.

  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. 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.

  19. 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.

  20. Sound speed profile characterization by the image source method

    OpenAIRE

    PINSON, Samuel; Guillon, Laurent

    2010-01-01

    This paper presents the first results of an imaging technique that measures the geoacoustic structure of a seafloor in shallow water areas. The devices used were a broadband 100 Hz–6 kHz acoustic source towed by a ship and a vertical array. Among all the acoustic paths existing in the water column, two are used: the direct one and the seabed-reflected one, the latter being composed of the reflections from the seafloor’s surface as well as that from each buried layer. Due to the good time re...

  1. 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

  2. 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

  3. 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...

  4. Optimal Sizing of a Photovoltaic-Hydrogen Power System for HALE Aircraft by means of Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Victor M. Sanchez

    2015-01-01

    Full Text Available Over the last decade there has been a growing interest in the research of feasibility to use high altitude long endurance (HALE aircrafts in order to provide mobile communications. The use of HALEs for telecommunication networks has the potential to deliver a wide range of communication services (from high-quality voice to high-definition videos, as well as high-data-rate wireless channels cost effectively. One of the main challenges of this technology is to design its power supply system, which must provide the enough energy for long time flights in a reliable way. In this paper a photovoltaic/hydrogen system is proposed as power system for a HALE aircraft due its high power density characteristic. In order to obtain the optimal sizing for photovoltaic/hydrogen system a particle swarm optimizer (PSO is used. As a case study, theoretical design of the photovoltaic/hydrogen power system for three different HALE aircrafts located at 18° latitude is presented. At this latitude, the range of solar radiation intensity was from 310 to 450 Wh/sq·m/day. The results obtained show that the photovoltaic/hydrogen systems calculated by PSO can operate during one year with efficacies ranging between 45.82% and 47.81%. The obtained sizing result ensures that the photovoltaic/hydrogen system supplies adequate energy for HALE aircrafts.

  5. 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.

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

    Science.gov (United States)

    Gilmore, Rick O; Thomas, Amanda L; Fesi, Jeremy

    2016-01-01

    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. PMID:27326860

  7. 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

    Due to the wind speed variation, wind shear and tower shadow effects, grid connected wind turbines are the sources of power fluctuations which may produce flicker during continuous operation. This paper presents a model of an MW-level variable-speed wind turbine with a doubly fed induction...... 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...... 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...

  8. 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.

  9. Annoyance and acceptability judgements of noise produced by three types of aircraft by residents living near JFK Airport

    Science.gov (United States)

    Borsky, P. N.

    1974-01-01

    A random sample of selected communities near JFK Airport were interviewed. Subsamples, with differing feelings of fear of aircraft crashes and different locations of residence were invited to participate in a laboratory experiment. The subjects were exposed to tape recordings of simulated flyovers of aircraft in approach and departure operations at nominal distances from the airport. The subjects judged the extent of noise annoyance and acceptability of the aircraft noises. Results indicate that level of noise is most significant in affecting annoyance judgements. Subjects with feelings of high fear report significantly more annoyance and less acceptability of aircraft noise than subjects with feelings of low fear.

  10. PREDICTION OF AIRCRAFT NOISE LEVELS

    Science.gov (United States)

    Clark, B. J.

    1994-01-01

    Methods developed at the NASA Lewis Research Center for predicting the noise contributions from various aircraft noise sources have been incorporated into a computer program for predicting aircraft noise levels either in flight or in ground test. The noise sources accounted for include fan inlet and exhaust, jet, flap (for powered lift), core (combustor), turbine, and airframe. Noise propagation corrections are available in the program for atmospheric attenuation, ground reflections, extra ground attenuation, and shielding. The capacity to solve the geometrical relationships between an aircraft in flight and an observer on the ground has been included in the program to make it useful in evaluating noise estimates and footprints for various proposed engine installations. The program contains two main routines for employing the noise prediction routines. The first main routine consists of a procedure to calculate at various observer stations the time history of the noise from an aircraft flying at a specified set of speeds, orientations, and space coordinates. The various components of the noise are computed by the program. For each individual source, the noise levels are free field with no corrections for propagation losses other than spherical divergence. The total spectra may then be corrected for the usual effects of atmospheric attenuation, extra ground attenuation, ground reflection, and aircraft shielding. Next, the corresponding values of overall sound pressure level, perceived noise level, and tone-weighted perceived noise level are calculated. From the time history at each point, true effective perceived noise levels are calculated. Thus, values of effective perceived noise levels, maximum perceived noise levels, and tone-weighted perceived noise levels are found for a grid of specified points on the ground. The second main routine is designed to give the usual format of one-third octave sound pressure level values at a fixed radius for a number of user

  11. 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 ...

  12. Aircraft Data Acquisition

    Directory of Open Access Journals (Sweden)

    Elena BALMUS

    2016-03-01

    Full Text Available 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 of this division in aviation, data optimization and comparison has been quite an important task. The interest in using data acquisition boards is being driven by the technology and design standards in the new generation of aircraft and the ongoing efforts of reducing weight and, in some cases addressing the safety risks. This paper presents a sum of technical report data from post processing and diversification of data acquisition from Arinc 429 interface on a research aircraft platform. Arinc 429 is by far the most common data bus in use on civil transport aircraft, regional jets and executive business jets today. Since its introduction on the Boeing 757/767 and Airbus aircraft in the early 1980s hardly any aircraft has been produced without the use of this data bus. It was used widely by the air transport indu

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Effect of electromagnetic interference by neonatal transport equipment on aircraft operation.

    Science.gov (United States)

    Nish, W A; Walsh, W F; Land, P; Swedenburg, M

    1989-06-01

    The number of civilian air ambulance services operating in the United States has been steadily increasing. The quantity and sophistication of electronic equipment used during neonatal transport have also increased. All medical equipment generates some electromagnetic interference (EMI). Excessive EMI can interfere with any of an aircraft's electrical systems, including navigation and communications. The United States military has strict standards for maximum EMI in transport equipment. Over the past 15 years, approximately 70% of neonatal transport monitors, ventilators, and incubators have failed testing due to excessive EMI. As neonatal transport equipment becomes more sophisticated, EMI is increased, and there is greater potential for aircraft malfunction. The Federal Aviation Administration should develop civilian standards for acceptable EMI, civilian aircraft operators must be aware of the possible dangers of excessive EMI, and equipment which does not meet future FAA standards should not be purchased. PMID:2751593

  18. Greenhouse effects of aircraft emissions as calculated by a radiative transfer model

    Directory of Open Access Journals (Sweden)

    J. P. F. Fortuin

    Full Text Available With a radiative transfer model, assessments are made of the radiative forcing in northern mid-latitudes due to aircraft emissions up to 1990. Considered are the direct climate effects from the major combustion products carbon dioxide, nitrogen dioxide, water vapor and sulphur dioxide, as well as the indirect effect of ozone production from NOx emissions. Our study indicates a local radiative forcing at the tropopause which should be negative in summer (–0.5 to 0.0 W/m2 and either negative or positive in winter (–0.3 to 0.2 W/m2. To these values the indirect effect of contrails has to be added, which for the North Atlantic Flight Corridor covers the range –0.2 to 0.3 W/m2 in summer and 0.0 to 0.3 W/m2 in winter. Apart from optically dense non-aged contrails during summer, negative forcings are due to solar screening by sulphate aerosols. The major positive contributions come from contrails, stratospheric water vapor in winter and ozone in summer. The direct effect of NO2 is negligible and the contribution of CO2 is relatively small.

  19. Flux measurements by the NRC Twin Otter atmospheric research aircraft: 1987-2011

    Science.gov (United States)

    Desjardins, Raymond L.; Worth, Devon E.; MacPherson, J. Ian; Bastian, Matthew; Srinivasan, Ramesh

    2016-03-01

    Over the past 30 years, the Canadian Twin Otter research group has operated an aircraft platform for the study of atmospheric greenhouse gas fluxes (carbon dioxide, ozone, nitrous oxide and methane) and energy exchange (latent and sensible heat) over a wide range of terrestrial ecosystems in North America. Some of the acquired data from these projects have now been archived at the Flight Research Laboratory and Agriculture and Agri-Food Canada. The dataset, which contains the measurements obtained in eight projects from 1987 to 2011 are now publicly available. All these projects were carried out in order to improve our understanding of the biophysical controls acting on land-surface atmosphere fluxes. Some of the projects also attempted to quantify the impacts of agroecosystems on the environment. To provide information on the data available, we briefly describe each project and some of the key findings by referring to previously published relevant work. As new flux analysis techniques are being developed, we are confident that much additional information can be extracted from this unique data set.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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

  6. GeoTrack: bio-inspired global video tracking by networks of unmanned aircraft systems

    Science.gov (United States)

    Barooah, Prabir; Collins, Gaemus E.; Hespanha, João P.

    2009-05-01

    Research from the Institute for Collaborative Biotechnologies (ICB) at the University of California at Santa Barbara (UCSB) has identified swarming algorithms used by flocks of birds and schools of fish that enable these animals to move in tight formation and cooperatively track prey with minimal estimation errors, while relying solely on local communication between the animals. This paper describes ongoing work by UCSB, the University of Florida (UF), and the Toyon Research Corporation on the utilization of these algorithms to dramatically improve the capabilities of small unmanned aircraft systems (UAS) to cooperatively locate and track ground targets. Our goal is to construct an electronic system, called GeoTrack, through which a network of hand-launched UAS use dedicated on-board processors to perform multi-sensor data fusion. The nominal sensors employed by the system will EO/IR video cameras on the UAS. When GMTI or other wide-area sensors are available, as in a layered sensing architecture, data from the standoff sensors will also be fused into the GeoTrack system. The output of the system will be position and orientation information on stationary or mobile targets in a global geo-stationary coordinate system. The design of the GeoTrack system requires significant advances beyond the current state-of-the-art in distributed control for a swarm of UAS to accomplish autonomous coordinated tracking; target geo-location using distributed sensor fusion by a network of UAS, communicating over an unreliable channel; and unsupervised real-time image-plane video tracking in low-powered computing platforms.

  7. Mission management aircraft operations manual

    Science.gov (United States)

    1992-01-01

    This manual prescribes the NASA mission management aircraft program and provides policies and criteria for the safe and economical operation, maintenance, and inspection of NASA mission management aircraft. The operation of NASA mission management aircraft is based on the concept that safety has the highest priority. Operations involving unwarranted risks will not be tolerated. NASA mission management aircraft will be designated by the Associate Administrator for Management Systems and Facilities. NASA mission management aircraft are public aircraft as defined by the Federal Aviation Act of 1958. Maintenance standards, as a minimum, will meet those required for retention of Federal Aviation Administration (FAA) airworthiness certification. Federal Aviation Regulation Part 91, Subparts A and B, will apply except when requirements of this manual are more restrictive.

  8. 75 FR 28504 - Airworthiness Directives; Various Aircraft Equipped With Rotax Aircraft Engines 912 A Series Engines

    Science.gov (United States)

    2010-05-21

    ... Directives; Various Aircraft Equipped With Rotax Aircraft Engines 912 A Series Engines AGENCY: Federal... 912 A series engine installed in various aircraft does not have an engine type certificate; instead, the engine is part of the aircraft type design. You may obtain further information by examining...

  9. 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...

  10. a New Method to Detect Regions Endangered by High Wind Speeds

    Science.gov (United States)

    Fischer, P.; Ehrensperger, S.; Krauß, T.

    2016-06-01

    In this study we evaluate whether the methodology of Boosted Regression Trees (BRT) suits for accurately predicting maximum wind speeds. As predictors a broad set of parameters derived from a Digital Elevation Model (DEM) acquired within the Shuttle Radar Topography Mission (SRTM) is used. The derived parameters describe the surface by means of quantities (e.g. slope, aspect) and quality (landform classification). Furthermore land cover data from the CORINE dataset is added. The response variable is maximum wind speed, measurements are provided by a network of weather stations. The area of interest is Switzerland, a country which suits perfectly for this study because of its highly dynamic orography and various landforms.

  11. 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.

  12. 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...

  13. 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 ...

  14. 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.

  15. Insights Into Precipitation Processes As Revealed By Profiling Radar, Disdrometer and Aircraft Observations During The MC3E Campaign.

    Science.gov (United States)

    Giangrande, S. E.; Toto, T.; Mishra, S.; Ryzhkov, A.; Bansemer, A.; Kumjian, M.

    2014-12-01

    The Midlatitude Continental Convective Clouds Experiment (MC3E) was a collaborative campaign led by the National Aeronautic and Space Administration's (NASA's) Global Precipitation Measurement (GPM) mission and the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program. This campaign was held at the DOE ARM Southern Great Plains (SGP) Central Facility (CF) in north-central Oklahoma, with the programs joining forces to deploy an extensive array of airborne, radiosonde and ground-based instrumentation towards an unprecedented set of deep convective environment and cloud property observations. An overarching motivation was to capitalize on the wealth of aircraft observations and new multi-frequency dual-polarization radars to provide insights for improving the treatments of cloud processes in convective models. This study considers a coupled aircraft, radar and surface disdrometer approach for identifying key cloud processes and linking those to possible radar-based microphysical fingerprints and/or cloud properties. Our emphasis is on the MC3E observations collected during aircraft spirals over the column of the ARM CF. We focus on those spirals associated with radar 'bright band' signatures and Doppler spectral anomalies observed within trailing stratifrom precipitation. Two cases are highlighted, one following a weaker convective event, and one following a stronger squall line. For each event, we investigate the usefulness of radar to inform on processes including aggregation and riming as viewed by the vertically-pointing ARM wind profiler (915 MHz) and cloud radar Doppler spectral observations (35 GHz). Matching dual-polarization radar signatures from nearby cm-wavelength radar are also consulted for complementary insights. For one event, the successive Citation II aircraft spirals through the melting layer and associated ground observations indicate a fortunate capture of the transition from a region of riming to one favoring aggregation

  16. 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.

  17. Studies of factors for speeding up mellowness of yellow rice wine by irradiation

    International Nuclear Information System (INIS)

    The paper described the research result of the factors for speeding up mellowness of yellow rice wine by irradiation of low dosage. The effect of speeding up its mellowness was gained through the research of different dosage, irradiated temperature, different container, space of container and storing temperature etc.. The experiment indicated that the best dosage was 100-600 Gy with 30-40 deg C tempreature; the pottery container for wraping wine was better than the glass one; the better space was 100 ml empty of one container and the storing time of irradiated wine covered 5-6 months

  18. 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.

  19. Influence of traverse speed on surface irregularities created by the abrasive waterjet

    Directory of Open Access Journals (Sweden)

    J. Valíček

    2012-01-01

    Full Text Available The paper deals with the calculation of the optimal traverse speed for diff erent types of materials, which is very important for predication, imaginings and dimensioning of technological factors and selection of the materials with the aim to increase of surface quality at abrasive waterjet cutting (AWJ technology. The surface irregularities of the experimental used materials AISI 304, AISI 309 have been measured by non-contact shadow method. New empirically compiled equations of the infl uence of the traverse speed on tensometrical state of cut, deformation resistance of material and surface roughness Ra are at AWJ cutting available.

  20. 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.

  1. Estimation of extreme wind speed in SCS and NWP by a non-stationary model

    Directory of Open Access Journals (Sweden)

    Lizhen Wang

    2016-05-01

    Full Text Available In offshore engineering design, it is considerably significant to have an adequately accurate estimation of marine environmental parameters, in particular, the extreme wind speed of tropical cyclone (TC with different return periods to guarantee the safety in projected operating life period. Based on the 71-year (1945–2015 TC data in the Northwest Pacific (NWP by the Joint Typhoon Warning Center (JTWC of US, a notable growth of the TC intensity is observed in the context of climate change. The fact implies that the traditional stationary model might be incapable of predicting parameters in the extreme events. Therefore, a non-stationary model is proposed in this study to estimate extreme wind speed in the South China Sea (SCS and NWP. We find that the extreme wind speeds of different return periods exhibit an evident enhancement trend, for instance, the extreme wind speeds with different return periods by non-stationary model are 4.1%–4.4% higher than stationary ones in SCS. Also, the spatial distribution of extreme wind speed in NWP has been examined with the same methodology by dividing the west sea areas of the NWP 0°–45°N, 105°E–130°E into 45 subareas of 5°×5°, where oil and gas resources are abundant. Similarly, remarkable spacial in-homogeneity in the extreme wind speed is seen in this area: the extreme wind speed with 50-year return period in the subarea (15°N–20°N, 115°E–120°E of Zhongsha and Dongsha Islands is 73.8 m/s, while that in the subarea of Yellow Sea (30°N–35°N, 120°E–125°E is only 47.1 m/s. As a result, the present study demonstrates that non-stationary and in-homogeneous effects should be taken into consideration in the estimation of extreme wind speed.

  2. 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.

  3. Improvements on computations of high speed propeller unsteady aerodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bousquet, J.M.; Gardarein, P. [Office National d' Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)

    2003-09-01

    This paper presents the application of the CANARI flow solver to the computation of unsteady effects in the aerodynamic interaction of a high speed propeller with the aircraft. The method is first validated on the APIAN isolated propeller test case by comparison with experiment at M = 0.7. The method is then applied to the time accurate 3D Euler computation of a generic transport aircraft at M = 0.68. Analysis of the results shows significant unsteady effects both on the propeller forces and on the wing aerodynamic flows, by comparison with steady computations. (authors)

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

    Directory of Open Access Journals (Sweden)

    Jiann-Jyh Wang

    2015-09-01

    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.

  5. 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

  6. 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...

  7. 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

  8. 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

  9. Innovative production technology in aircraft construction: CIAM Forming 'made by MBB' - A highly productive example

    Science.gov (United States)

    A novel production technology in aircraft construction was developed for manufacturing parts of shapes and dimensions that involve only small quantities for one machine. The process, called computerized integrated and automated manufacturing (CIAM), makes it possible to make ready-to-install sheet-metal parts for all types of aircraft. All of the system's job sequences, which include milling the flat sheet-metal parts in stacks, deburring, heat treatment, and forming under the high-pressure rubber-pad press, are automated. The CIAM production center, called SIAM Forming, fulfills the prerequisites for the cost-effective production of sheet-metal parts made of aluminum alloys, titanium, or steel. The SIAM procedure results in negligible material loss through computerizing both component-contour nesting of the sheet-metal parts and contour milling.

  10. 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.

  11. 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.

  12. 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.

  13. Greenhouse effects of aircraft emissions as calculated by a radiative transfer model

    OpenAIRE

    Fortuin, J.P.F.; Dorland, R.; Wauben, W. M. F.; Kelder, H.

    1995-01-01

    With a radiative transfer model, assessments are made of the radiative forcing in northern mid-latitudes due to aircraft emissions up to 1990. Considered are the direct climate effects from the major combustion products carbon dioxide, nitrogen dioxide, water vapor and sulphur dioxide, as well as the indirect effect of ozone production from NOx emissions. Our study indicates a local radiative forcing at the tropopause which should be negative in summe...

  14. Time series and correlation of pulsations observed simultaneously by two aircraft

    International Nuclear Information System (INIS)

    Geomagnetic pulsations are an interesting and ubiquitous component of the geomagnetic field and they have been studied extensively for several decades. Numerous comparisons have been made of pulsations at a variety of sites for various objectives. However, conductivity anomalies introduce a number of complexities into the interpretations of pulsations at ground sites through the action of the primary fields on the electrical properties of the local geologic structure. To avoid the difficulties associated with conductivity irregularities, Ochadlick et al. [1985] described an aeromagnetic approach using two aircraft for studying the relationship between pulsations observed over a deep ocean area. Relative to land regions, a deep sea is presumably a more uniform conductor. Using the dual aeromagnetic results, Ochadlick found that the correlation coefficient of pulsations remained relatively constant for observation points spaced apart from a few to about 150 km. Beyond 150 km the correlation coefficient was found to decrease. This letter summarizes the time series records of pulsations, totaling about 9 h, acquired during several dual aircraft flights performed between 20 May and 15 Aug 1985 and presents the associated correlation coefficient between the dual aircraft data sets. Apparently, those measurements show for the first time that a strong similarity of pulsations weakens quickly at a distance of ∼150 km which is remarkably close to the ionospheric height and is thus suggestive of a strong ionospheric control on the spatial coherence of pulsations

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. Determination of correlation functions of turbulent velocity and sound speed fluctuations by means of ultrasonic technique

    Science.gov (United States)

    Andreeva, Tatiana A.; Durgin, William W.

    2011-12-01

    An experimental study of the propagation of high-frequency acoustic waves through grid-generated turbulence by means of an ultrasound technique is discussed. Experimental data were obtained for ultrasonic wave propagation downstream of heated and non-heated grids in a wind tunnel. A semi-analytical acoustic propagation model that allows the determination of the spatial correlation functions of the flow field is developed based on the classical flowmeter equation and the statistics of the travel time of acoustic waves traveling through the kinematic and thermal turbulence. The basic flowmeter equation is reconsidered in order to take into account sound speed fluctuations and turbulent velocity fluctuations. It allows deriving an integral equation that relates the correlation functions of travel time, sound speed fluctuations and turbulent velocity fluctuations. Experimentally measured travel time statistics of data with and without grid heating are approximated by an exponential function and used to analytically solve the integral equation. The reconstructed correlation functions of the turbulent velocity and sound speed fluctuations are presented. The power spectral density of the turbulent velocity and sound speed fluctuations are calculated.

  20. Determination of correlation functions of turbulent velocity and sound speed fluctuations by means of ultrasonic technique

    Energy Technology Data Exchange (ETDEWEB)

    Andreeva, Tatiana A. [Saint-Petersburg State Polytechnic University, Department of Mathematical Sciences, Saint-Petersburg (Russian Federation); Durgin, William W. [California Polytechnic State University, Department of Mechanical Engineering, San Luis Obispo, CA (United States)

    2011-12-15

    An experimental study of the propagation of high-frequency acoustic waves through grid-generated turbulence by means of an ultrasound technique is discussed. Experimental data were obtained for ultrasonic wave propagation downstream of heated and non-heated grids in a wind tunnel. A semi-analytical acoustic propagation model that allows the determination of the spatial correlation functions of the flow field is developed based on the classical flowmeter equation and the statistics of the travel time of acoustic waves traveling through the kinematic and thermal turbulence. The basic flowmeter equation is reconsidered in order to take into account sound speed fluctuations and turbulent velocity fluctuations. It allows deriving an integral equation that relates the correlation functions of travel time, sound speed fluctuations and turbulent velocity fluctuations. Experimentally measured travel time statistics of data with and without grid heating are approximated by an exponential function and used to analytically solve the integral equation. The reconstructed correlation functions of the turbulent velocity and sound speed fluctuations are presented. The power spectral density of the turbulent velocity and sound speed fluctuations are calculated. (orig.)

  1. 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.

  2. 14 CFR 298.63 - Reporting of aircraft operating expenses and related statistics by small certificated air carriers.

    Science.gov (United States)

    2010-01-01

    ... the space provided for “Aircraft Type.” “Aircraft Type” refers to aircraft models such as Beech-18... and oil taxes. (iii) Line 5 “Other” expenses shall include general (hull) insurance, and all other... insurance, advertising and other promotion and publicity expenses, and the fringe benefit expenses...

  3. Intra-limb coordination while walking is affected by cognitive load and walking speed.

    Science.gov (United States)

    Ghanavati, Tabassom; Salavati, Mahyar; Karimi, Noureddin; Negahban, Hossein; Ebrahimi Takamjani, Ismail; Mehravar, Mohammad; Hessam, Masumeh

    2014-07-18

    Knowledge about intra-limb coordination (ILC) during challenging walking conditions provides insight into the adaptability of central nervous system (CNS) for controlling human gait. We assessed the effects of cognitive load and speed on the pattern and variability of the ILC in young people during walking. Thirty healthy young people (19 female and 11 male) participated in this study. They were asked to perform 9 walking trials on a treadmill, including walking at three paces (preferred, slower and faster) either without a cognitive task (single-task walking) or while subtracting 1׳s or 3׳s from a random three-digit number (simple and complex dual-task walking, respectively). Deviation phase (DP) and mean absolute relative phase (MARP) values-indicators of variability and phase dynamic of ILC, respectively-were calculated using the data collected by a motion capture system. We used a two-way repeated measure analysis of variance for statistical analysis. The results showed that cognitive load had a significant main effect on DP of right shank-foot and thigh-shank, left shank-foot and pelvis-thigh (peffect of walking speed was significant on DP of all segments in each side and MARP of both thigh-shank and pelvis-thigh segments (pcognitive load and walking speed was only significant for MARP values of left shank-foot and right pelvis-thigh (pcognitive load and speed could significantly affect the ILC and variability and phase dynamic during walking. PMID:24861632

  4. Diagnosis of power generator sets by analyzing the crank shaft angular speed

    International Nuclear Information System (INIS)

    This thesis deals with the diagnosis of a powerful 20-cylinder diesel engine which runs a generator set in a nuclear plant. The objective is to make a diagnosis by analyzing the crank shaft angular speed variations. Only combustion related faults are investigated. As the engine is very large, the first crank shaft natural modes are in the low frequencies. Torsional vibrations of the flexible crank shaft strongly complicate the analysis of the angular speed variations. Little attention has been paid to such large engines in the literature. First, a dynamical model with the assumption of a flexible crank shaft is established. The parameters of the model are optimized with the help of actual data. Then, an original automated diagnosis based on pattern recognition of the angular speed waveforms is proposed. Indeed, any faulty cylinder in combustion stroke will distort the angular speed waveform in a specific way which depends on its location with respect to nodes and anti-nodes of the modes. Reference patterns, representative of the engine conditions, are computed with the model constituting the main originality of this work. Promising results are obtained in operational phase. An experimental fuel leakage fault was correctly diagnosed, including detection and localization of the faulty cylinder and an indication of the severity of the fault. (author)

  5. Pulsed-Magnetic Processing and Its Application in the Aircraft Industry in Russia

    Institute of Scientific and Technical Information of China (English)

    V.A.Glushchenkov

    2007-01-01

      Pulse-magnetic technology occupies one of technological fields in up-to-day aircraft manufacturing.This method of processing belongs to high-speed dynamical methods of processing,which are characterized by parameters providing high quality of finished products and save on material and labour costs.……

  6. Brain white matter lesions detected by magnetic resosnance imaging are associated with balance and gait speed

    OpenAIRE

    John M Starr; Leaper, S A; Murray, A D; Lemmon, H A; Staff, R T; Deary, Ian J.; Whalley, Lawrence J.

    2003-01-01

    Objective: To investigate the relations between premorbid and current mental ability, mood, and white matter signal abnormalities detected by T2 weighted brain magnetic resonance imaging (MRI) and impairment of balance and mobility in older adults. Methods: 97 subjects from the Aberdeen 1921 birth cohort underwent brain MRI, evaluation of balance, and measurement of gait speed. White matter hyperintensities detected on T2 weighted MRI scans were rated by three independent raters on three ...

  7. 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

  8. 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

  9. High-speed monodisperse droplet generation by ultrasonically controlled micro-jet breakup

    Science.gov (United States)

    Frommhold, Philipp Erhard; Lippert, Alexander; Holsteyns, Frank Ludwig; Mettin, Robert

    2014-04-01

    A liquid jet that is ejected from a nozzle into air will disintegrate into drops via the well-known Plateau-Rayleigh instability within a certain range of Ohnesorge and Reynolds numbers. With the focus on the micrometer scale, we investigate the control of this process by superimposing a suitable ultrasonic signal, which causes the jet to break up into a very precise train of monodisperse droplets. The jet leaves a pressurized container of liquid via a small orifice of about 20 μm diameter. The break-up process and the emerging droplets are recorded via high-speed imaging. An extended parameter study of exit speed and ultrasonic frequency is carried out for deionized water to evaluate the jet's state and the subsequent generation of monodisperse droplets. Maximum exit velocities obtained reach almost 120 m s-1, and frequencies have been applied up to 1.8 MHz. Functionality of the method is confirmed for five additional liquids for moderate jet velocities 38 m s-1. For the uncontrolled jet disintegration, the drop size spectra revealed broad distributions and downstream drop growth by collision, while the acoustic control generated monodisperse droplets with a standard deviation less than 0.5 %. By adjustment of the acoustic excitation frequency, drop diameters could be tuned continuously from about 30 to 50 μm for all exit speeds. Good agreement to former experiments and theoretical approaches is found for the relation of overpressure and jet exit speed, and for the observed stability regions of monodisperse droplet generation in the parameter plane of jet speed and acoustic excitation frequency. Fitting of two free parameters of the general theory to the liquids and nozzles used is found to yield an even higher precision. Furthermore, the high-velocity instability limit of regular jet breakup described by von Ohnesorge has been superseded by more than a factor of two without entering the wind-induced instability regime, and monodisperse droplet generation was

  10. 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.

  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......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 appropriate strategy for minimizing their effects. This paper investigates the ASD's input current interharmonic sources caused by applying symmetrical regularly sampled fixed-frequency modulation techniques on the inverter. The interharmonics generation process is precisely formulated and comparative results...

  12. Propagation speed in a strip bounded by a line with different diffusion

    Science.gov (United States)

    Tellini, Andrea

    2016-04-01

    In this paper we consider a model for the diffusion of a population in a strip-shaped field, where the growth of the species is governed by a Fisher-KPP equation and which is bounded on one side by a road where the species can have a different diffusion coefficient. Dirichlet homogeneous boundary conditions are imposed on the other side of the strip. We prove the existence of an asymptotic speed of propagation which is greater than the one of the case without road and study its behavior for small and large diffusions on the road. Finally we prove that, when the width of the strip goes to infinity, the asymptotic speed of propagation approaches the one of a half-plane bounded by a road, case that has been recently studied in [2,3].

  13. APPLICATION FOR AIRCRAFT TRACKING

    OpenAIRE

    Ostroumov, Ivan; Kuz’menko, Natalia

    2011-01-01

    Abstract. In the article the important problems of software development for aircraft tracking have beendiscussed. Position reports of ACARS have been used for aircraft tracking around the world.An algorithm of aircraft coordinates decoding and visualization of aircraft position on the map has beenrepresented.Keywords: ACARS, aircraft, internet, position, software, tracking.

  14. Assessment of aircraft structural integrity by detecting disbonds through ultrasonic scanning

    Science.gov (United States)

    Abedin, M. N.; Prabhu, D. R.; Winfree, W. P.

    1992-01-01

    A study of nondestructive evaluation of aircraft bonded joints using the contact scanning technique is presented. Reflected signals acquired through the contacting transducer characterize the test region as being bonded or disbonded. Ultrasonic signals are attenuated more rapidly in the bonded regions when compared to disbonded regions. A peak amplitude based method and an artificial neural network are used to classify the signals. Results obtained using an artificial neural network exhibited significant insensitivity to signal variation when compared to the peak amplitude. Very good agreement is observed between results obtained using the present technique and those obtained using immersion scanning.

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Ali Heidari

    2013-01-01

    Full Text Available 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.

  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. A NEW METHOD TO DETECT REGIONS ENDANGERED BY HIGH WIND SPEEDS

    Directory of Open Access Journals (Sweden)

    P. Fischer

    2016-06-01

    Full Text Available In this study we evaluate whether the methodology of Boosted Regression Trees (BRT suits for accurately predicting maximum wind speeds. As predictors a broad set of parameters derived from a Digital Elevation Model (DEM acquired within the Shuttle Radar Topography Mission (SRTM is used. The derived parameters describe the surface by means of quantities (e.g. slope, aspect and quality (landform classification. Furthermore land cover data from the CORINE dataset is added. The response variable is maximum wind speed, measurements are provided by a network of weather stations. The area of interest is Switzerland, a country which suits perfectly for this study because of its highly dynamic orography and various landforms.

  19. 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

  20. Measurement of ozone and water vapor by Airbus in-service aircraft: The MOZAIC airborne program, An overview

    Science.gov (United States)

    Marenco, Alain; Thouret, ValéRie; NéDéLec, Philippe; Smit, Herman; Helten, Manfred; Kley, Dieter; Karcher, Fernand; Simon, Pascal; Law, Kathy; Pyle, John; Poschmann, Georg; von Wrede, Rainer; Hume, Chris; Cook, Tim

    1998-10-01

    Tentative estimates, using three-dimensional chemistry and transport models, have suggested small ozone increases in the upper troposphere resulting from current aircraft emissions, but have also concluded to significant deficiencies in today's models and to the need to improve them through comparison with extended data sets. The Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program was initiated in 1993 by European scientists, aircraft manufacturers, and airlines to collect experimental data. Its goal is to help understand the atmosphere and how it is changing under the influence of human activity, with particular interest in the effects of aircraft. MOZAIC consists of automatic and regular measurements of ozone and water vapor by five long range passenger airliners flying all over the world. The aim is not to detect direct effects of aircraft emissions on the ozone budget inside the air traffic corridors but to build a large database of measurements to allow studies of chemical and physical processes in the atmosphere, and hence to validate global chemistry transport models. MOZAIC data provide, in particular, detailed ozone and water vapor climatologies at 9-12 km where subsonic aircraft emit most of their exhaust and which is a very critical domain (e.g., radiatively and stratosphere/troposphere exchanges) still imperfectly described in existing models. This will be valuable to improve knowledge about the processes occuring in the upper troposphere and the lowermost stratosphere, and the model treatment of near tropopause chemistry and transport. During MOZAIC I (January 1993-September 1996), fully automatic devices were developed, installed aboard five commercial Airbus A340s, and flown in normal airline service. A second phase, MOZAIC II, started in October 1996 with the aim of continuing the O3 and H2O measurements and doing a feasibility study of new airborne devices (CO, NOy). Between September 1994 and December 1997, 7500

  1. Estimation of extreme wind speed in SCS and NWP by a non-stationary model

    OpenAIRE

    Lizhen Wang; Jiachun Li

    2016-01-01

    In offshore engineering design, it is considerably significant to have an adequately accurate estimation of marine environmental parameters, in particular, the extreme wind speed of tropical cyclone (TC) with different return periods to guarantee the safety in projected operating life period. Based on the 71-year (1945–2015) TC data in the Northwest Pacific (NWP) by the Joint Typhoon Warning Center (JTWC) of US, a notable growth of the TC intensity is observed in the context of climate change...

  2. Aerobic and anaerobic swimming speeds of spermatozoa investigated by twin beam laser velocimetry.

    OpenAIRE

    Wilson, M C; Harvey, J D; Shannon, P.

    1987-01-01

    The motility of bovine and ovine spermatozoa has been studied under aerobic and anaerobic conditions, using a dual beam laser velocimeter. Cells swimming under aerobic conditions were found to be characterized by a translational swimming speed and a rotation rate that were approximately double those of cells swimming in an anaerobic environment. Both types of spermatozoa have been found to exhibit a sudden coordinated transition between fast and slow swimming states when the available oxygen ...

  3. 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-...

  4. 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.

  5. 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.

  6. Front Speed Enhancement by Incompressible Flows in Three or Higher Dimensions

    Science.gov (United States)

    El Smaily, Mohammad; Kirsch, Stéphane

    2014-07-01

    We study, in dimensions N ≥ 3, the family of first integrals of an incompressible flow: these are functions whose level surfaces are tangential to the streamlines of the advective incompressible field. One main motivation for this study comes from earlier results proving that the existence of nontrivial first integrals of an incompressible flow q is the main key that leads to a "linear speed up" by a large advection of pulsating traveling fronts solving a reaction-advection-diffusion equation in a periodic heterogeneous framework. The family of first integrals is not well understood in dimensions N ≥ 3 due to the randomness of the trajectories of q and this is in contrast with the case N = 2. By looking at the domain of propagation as a union of different components produced by the advective field, we provide more information about first integrals and we give a class of incompressible flows which exhibit "ergodic components" of positive Lebesgue measure (and hence are not shear flows) and which, under certain sharp geometric conditions, speed up the KPP fronts linearly with respect to the large amplitude. In the proofs, we establish a link between incompressibility, ergodicity, first integrals and the dimension to give a sharp condition about the asymptotic behavior of the minimal KPP speed in terms of the configuration of ergodic components.

  7. Rail temperature rise characteristics caused by linear eddy current brake of high-speed train

    Directory of Open Access Journals (Sweden)

    Xiaoshan Lu

    2014-12-01

    Full Text Available The rail temperature rises when the linear eddy current brake of high-speed train is working, which may lead to a change of rail physical characteristics or an effect on train operations. Therefore, a study concerning the characteristics of rail temperature rise caused by eddy current has its practical necessity. In the research, the working principle of a linear eddy current brake is introduced and its FEA model is established. According to the generation mechanism of eddy current, the theoretical formula of the internal energy which is produced by the eddy current is deduced and the thermal load on the rail is obtained. ANSYS is used to simulate the rail temperature changes under different conditions of thermal loads. The research result shows the main factors which contribute to the rising of rail temperature are the train speed, brake gap and exciting current. The rail temperature rises non-linearly with the increase of train speed. The rail temperature rise curve is more sensitive to the exciting current than the air gap. Moreover, the difference stimulated by temperature rising between rails of 60 kg/m and 75 kg/m is presented as well.

  8. 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

  9. HUMAN FACTOR IMPACT IN MILITARY AIRCRAFT MAINTENANCE

    OpenAIRE

    MARINKOVIC SRBOLJUB J.; DRENOVAC ALEKSANDAR Z.

    2015-01-01

    Aircraft maintenance, as a specific field of military materiel maintenance, is characterized by high reliability standards, based on regulations and technical standards. A system approach to maintenance represents the key element of maintenance quality, while aircraft maintenance staff has a crucial influence on the final outcome of aircraft maintenance.

  10. 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.

  11. 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.

  12. 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.

  13. Interplay between path and speed in decision making by high-dimensional stochastic gene regulatory networks.

    Directory of Open Access Journals (Sweden)

    Nuno R Nené

    Full Text Available Induction of a specific transcriptional program by external signaling inputs is a crucial aspect of intracellular network functioning. The theoretical concept of coexisting attractors representing particular genetic programs is reasonably adapted to experimental observations of "genome-wide" expression profiles or phenotypes. Attractors can be associated either with developmental outcomes such as differentiation into specific types of cells, or maintenance of cell functioning such as proliferation or apoptosis. Here we review a mechanism known as speed-dependent cellular decision making (SdCDM in a small epigenetic switch and generalize the concept to high-dimensional space. We demonstrate that high-dimensional network clustering capacity is dependent on the level of intrinsic noise and the speed at which external signals operate on the transcriptional landscape.

  14. 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.

  15. 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. PMID:26804750

  16. 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...

  17. Vision-based measurement for rotational speed by improving Lucas-Kanade template tracking algorithm.

    Science.gov (United States)

    Guo, Jie; Zhu, Chang'an; Lu, Siliang; Zhang, Dashan; Zhang, Chunyu

    2016-09-01

    Rotational angle and speed are important parameters for condition monitoring and fault diagnosis of rotating machineries, and their measurement is useful in precision machining and early warning of faults. In this study, a novel vision-based measurement algorithm is proposed to complete this task. A high-speed camera is first used to capture the video of the rotational object. To extract the rotational angle, the template-based Lucas-Kanade algorithm is introduced to complete motion tracking by aligning the template image in the video sequence. Given the special case of nonplanar surface of the cylinder object, a nonlinear transformation is designed for modeling the rotation tracking. In spite of the unconventional and complex form, the transformation can realize angle extraction concisely with only one parameter. A simulation is then conducted to verify the tracking effect, and a practical tracking strategy is further proposed to track consecutively the video sequence. Based on the proposed algorithm, instantaneous rotational speed (IRS) can be measured accurately and efficiently. Finally, the effectiveness of the proposed algorithm is verified on a brushless direct current motor test rig through the comparison with results obtained by the microphone. Experimental results demonstrate that the proposed algorithm can extract accurately rotational angles and can measure IRS with the advantage of noncontact and effectiveness. PMID:27607300

  18. High-speed camera analysis for nanoparticles produced by using a pulsed wire-discharge method

    Science.gov (United States)

    Kim, Jong Hwan; Kim, Dae Sung; Ryu, Bong Ki; Suematsu, Hisayuki; Tanaka, Kenta

    2016-07-01

    We investigated the performance of a high-speed camera and the nanoparticle size distribution to quantify the mechanism of synthesized nanoparticle formation in a pulsed wire discharge (PWD) experiment. The Sn-58Bi alloy wire was 0.5 mm in diameter and 32 mm long; it was prepared in the PWD chamber, and the evaporation explosion process was observed by using a high-speed camera. In order to vary the conditions and analyze the mechanisms of nanoparticle synthesis in the PWD, we changed the pressure of the N2 gas in the chamber from 25 to 75 kPa. To synthesize nanoparticles on a nano-scale, we fixed the charging voltage at 6 kV, and the high-speed camera captured pictures at 22,500 frames per second. The experimental results show that the electronic explosion process at different N2 gas pressures can be characterized by using the explosion's duration and the explosion's intensity. The experiments at the lowest pressure exhibited a longer explosion duration and a greater intensity. Also, at low pressure, very small nanoparticles with a good dispersion were produced.

  19. Perceptions of Speed and Risk: Experimental Studies of Road Crossing by Older People.

    Science.gov (United States)

    Butler, Annie A; Lord, Stephen R; Fitzpatrick, Richard C

    2016-01-01

    Crossing a road safely is a complex task requiring good sensorimotor function and integration of information about traffic speed, distances and one's own speed. Poor judgement through age-related sensorimotor or cognitive impairment or a predisposition to take risks could lead to errors with serious consequences. On a simulated road, 85 participants (age ≥70 years) were asked to cross in front of an approaching car with a clearance as small as considered safe in two conditions; (1) with nothing else to attend to (free crossing) and (2) with an additional ball-gathering task while waiting to cross (task crossing). Participants were categorised according to their crossing outcome (failed to cross, 'hit', exact, safe, cautious). Participants also performed two sub-studies; (1) the perception of the time-to-arrival of moving objects and (2) the perception of own gait speed. Physical and cognitive function and everyday risk-taking behaviour were also assessed. In free crossing, clearances varied but no participants were "hit" by the car. In task crossing, participants allowed smaller clearances and 10% of participants would have been hit while 13% missed the opportunity to cross altogether. Across a wide range of physical and cognitive measures, including perceived and actual gait speed, a consistent pattern was observed in the task crossing condition. The exact group performed best, the 'hit', safe and cautious groups performed less well while those who missed the opportunity (fail) performed worst. The exact group reported taking the greatest risks in everyday life whereas the remaining groups reported being cautious. In conclusion, we found older people with poorer perceptual, physical and cognitive function made inappropriate and risky decisions in a divided attention road-crossing task despite self-reports of cautious behaviour in everyday life. PMID:27054918

  20. 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°.

  1. 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.

  2. 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.

  3. 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.

  4. Experiments on liquid droplet impingement erosion by high-speed spray

    Energy Technology Data Exchange (ETDEWEB)

    Fujisawa, Nobuyuki, E-mail: fujisawa@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata, Niigata, 950-2181 (Japan); Yamagata, Takayuki, E-mail: yamagata@eng.niigata-u.ac.jp [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata, Niigata, 950-2181 (Japan); Hayashi, Kanto [Graduate School of Science and Technology, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata, Niigata, 950-2181 (Japan); Takano, Tsuyoshi [Visualization Research Center, Niigata University, 8050, Ikarashi 2-Nocho, Nishi-ku, Niigata, Niigata, 950-2181 (Japan)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer The liquid droplet impingement erosion is studied experimentally. Black-Right-Pointing-Pointer Droplets have a diameter of tens of micrometers in the high-speed spray. Black-Right-Pointing-Pointer Droplet velocity, diameter, number are measured by optical techniques. Black-Right-Pointing-Pointer The erosion rate depends on the droplet velocity to the power of 7. - Abstract: In the present paper, liquid droplet impingement erosion is studied by using a high-speed spray. This experiment allows the evaluation of erosion rate of solid materials due to the impingement of liquid droplets having an order of tens of micrometer in diameter, which corresponds to those of actual conditions in nuclear power plants. The droplet properties are characterized by measuring the droplet velocity by particle image velocimetry, the diameter by shadowgraph and the number of impinging droplets in a unit area by sampling probe. The erosion rate of aluminum material by water droplets is tested by the high-speed spray in some combinations of the distances from the nozzle and droplet velocities. Although the experimental erosion rate in the far field of the nozzle is reproduced by the theoretical erosion model, the erosion rate in the near field does not. This suggests the damping effect of liquid film over the test specimen in the near field. The experimental result also indicates that the erosion rate increases in proportional to the power of 7.0 of droplet velocity in the maximum rate stage. The result indicates a certain degree of deviation from the previous experiment in literature, which may suggest the influence of the droplet diameter and the liquid film on the liquid droplet impingement erosion.

  5. Forward Looking Radar Imaging by Truncated Singular Value Decomposition and Its Application for Adverse Weather Aircraft Landing

    OpenAIRE

    Yulin Huang; Yuebo Zha; Yue Wang; Jianyu Yang

    2015-01-01

    The forward looking radar imaging task is a practical and challenging problem for adverse weather aircraft landing industry. Deconvolution method can realize the forward looking imaging but it often leads to the noise amplification in the radar image. In this paper, a forward looking radar imaging based on deconvolution method is presented for adverse weather aircraft landing. We first present the theoretical background of forward looking radar imaging task and its application for aircraft la...

  6. Variance in Broad Reading Accounted for by Measures of Reading Speed Embedded within Maze and Comprehension Rate Measures

    Science.gov (United States)

    Hale, Andrea D.; Skinner, Christopher H.; Wilhoit, Brian; Ciancio, Dennis; Morrow, Jennifer A.

    2012-01-01

    Maze and reading comprehension rate measures are calculated by using measures of reading speed and measures of accuracy (i.e., correctly selected words or answers). In sixth- and seventh-grade samples, we found that the measures of reading speed embedded within our Maze measures accounted for 50% and 39% of broad reading score (BRS) variance,…

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Direct observation of high-speed plasma outflows produced by magnetic reconnection in solar impulsive events

    CERN Document Server

    Wang, Tongjiang; Qiu, Jiong

    2007-01-01

    Spectroscopic observations of a solar limb flare recorded by SUMER on SOHO reveal, for the first time, hot fast magnetic reconnection outflows in the corona. As the reconnection site rises across the SUMER spectrometer slit, significant blue- and red-shift signatures are observed in sequence in the Fe XIX line, reflecting upflows and downflows of hot plasma jets, respectively. With the projection effect corrected, the measured outflow speed is between 900-3500 km/s, consistent with theoretical predictions of the Alfvenic outflows in magnetic reconnection region in solar impulsive events. Based on theoretic models, the magnetic field strength near the reconnection region is estimated to be 19-37 Gauss.

  13. NASA Lewis 9- by 15-foot low-speed wind tunnel user manual

    Science.gov (United States)

    Soeder, Ronald H.

    1993-01-01

    This manual describes the 9- by 15-Foot Low-Speed Wind Tunnel at the Lewis Research Center and provides information for users who wish to conduct experiments in this atmospheric facility. Tunnel variables such as pressures, temperatures, available tests section area, and Mach number ranges (0.05 to 0.20) are discussed. In addition, general support systems such as air systems, hydraulic system, hydrogen system, laser system, flow visualization system, and model support systems are described. Instrumentation and data processing and acquisition systems are also discussed.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. Bullet Retarding Forces in Ballistic Gelatin by Analysis of High Speed Video

    CERN Document Server

    Gaylord, Steven; Courtney, Michael; Courtney, Amy

    2013-01-01

    Though three distinct wounding mechanisms (permanent cavity, temporary cavity, and ballistic pressure wave) are described in the wound ballistics literature, they all have their physical origin in the retarding force between bullet and tissue as the bullet penetrates. If the bullet path is the same, larger retarding forces produce larger wounding effects and a greater probability of rapid incapacitation. By Newton's third law, the force of the bullet on the tissue is equal in magnitude and opposite in direction to the force of the tissue on the bullet. For bullets penetrating with constant mass, the retarding force on the bullet can be determined by frame by frame analysis of high speed video of the bullet penetrating a suitable tissue simulant such as calibrated 10% ballistic gelatin. Here the technique is demonstrated with 9mm NATO bullets, 32 cm long blocks of gelatin, and a high speed video camera operating at 20,000 frames per second. It is found that different 9mm NATO bullets have a wide variety of pot...

  19. Fly in Atmosphere by Drag Force - Easy Thrust Generation Aircraft Engine Based Physics

    Science.gov (United States)

    Pierre Celestin, Mwizerwa

    2013-11-01

    This paper aims to present to the science community another way to fly in atmosphere, a way which is much more cheaper, efficient, safe and easy. Over the years scientists have been trying to find a way to built the vertically taking off vehicles but there have been no satisfactory success(what have been found was very expensive), Even aircrafts we know now need very sophisticated and expensive engines and not efficient enough. This way of flying may help our governments to spend less money on technologies and will help people to travel at very low prices so that, it may be a solution to the crisis which the world faces nowadays. In other words, it is my proposal to the next generation technologies we was looking for for years because everything can fly from the car to the trucks, the spaceships and even the hotels maybe constructed and fly as we construct the ships which sail in the oceans. My way of flying will have many applications in all the aspect of travel as it is going to be explained.

  20. 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.

  1. 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.

  2. 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.

  3. 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. PMID:27374588

  4. 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.

  5. 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.

  6. 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.

  7. Accuracy and speed of response to different voice types in a cockpit voice warning system

    Science.gov (United States)

    Freedman, J.; Rumbaugh, W. A.

    1983-09-01

    Voice warning systems (VWS) in aircraft cockpits provide a valuable means of warning identification. Improvements in technology have made the VWS a viable addition to aircraft warning systems. This thesis was an experiment to determine the best voice type (male, female, or neutral machine) for use in a VWS for military aircraft. Different levels of engine background noise, signal to noise ratio of the warning message, and precursor delivery formats were used. The experiment had ten subjects performing a primary tracking task; at random intervals a voice warning was interjected, requiring that the subjects respond by pushing the correct button. The results of this experiment contradict some previous beliefs and findings. The male voice was associated with more accurate responses for voice warning systems in the military aircraft environment. For speed of response the results were more complicated; the male voice was generally more closely associated with faster response times for accurate responses.

  8. Transport of north China air pollution by midlatitude cyclones: Case study of aircraft measurements in summer 2007

    Science.gov (United States)

    Ding, Aijun; Wang, Tao; Xue, Likun; Gao, Jian; Stohl, Andreas; Lei, Hengchi; Jin, Dezhen; Ren, Yu; Wang, Xuezhong; Wei, Xiaolin; Qi, Yanbin; Liu, Jian; Zhang, Xiaoqing

    2009-04-01

    Warm conveyor belts (WCBs) and frontal activity play important roles in the long-range transport of air pollutants by lifting them from the planetary boundary layer (PBL) into the free troposphere (FT) in midlatitudes. In summer 2007, an aircraft study was carried out in northeast (NE) China in order to understand the role of midlatitude cyclones in air pollution transport in north and east China in warm seasons. During a flight on 27 June, high concentrations of ozone and related trace gases were observed, with maximum concentrations (O3 ˜ 140 ppbv, SO2 ˜ 14.6 ppbv, CO ˜ 1185 ppbv) recorded at an altitude of 2.6 km. In this paper we present a detailed analysis of this flight. The mesoscale meteorological model Weather Research and Forecasting (WRF) and a Lagrangian dispersion model called FLEXPART were used to aid the diagnostic analysis of the atmospheric dynamic structure and the understanding of the transport characteristics of regional and local air pollution. The flight took place in a region adjacent to a warm front associated with a weak cyclone in north China. The aircraft sampled both the WCB and warm air frontal zone of the cyclone. The simulations show that the observed high air pollution in the FT mostly originated from the North China Plain, especially the megacities Beijing and Tianjin. Their plumes were vented by a stagnant front, probably through, in part, topographic lifting by the mountains in the north, and then were quickly transported in the FT to the study region. Trajectory analysis and satellite data suggest that the observed air masses were further lifted by the WCB into the middle and upper troposphere and were exported from Asia toward North America and the Arctic.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Mapping Nonsquare and Unevenly Spaced 2-D SLDV Data of an Aircraft Fuselage by Using Spatial DFT-IDFT Techniques

    Directory of Open Access Journals (Sweden)

    William Xinzuo Li

    1996-01-01

    Full Text Available The scanning laser Doppler vibrometry (SLDV technique provides velocities of a structure at 2-dimensional (2-D angularly evenly spaced (in the laser scanning sense data points. This causes an unevenly spaced data point distribution on the surface of the test structure. In many cases evenly spaced data point distribution with square or rectangular grids is highly desirable. In this study the SLDV velocity data of a partial surface area of an aircraft fuselage were mapped to truly spatial evenly spaced coordinates by using the spatial DFT-IDFT technique with minimum distortion. This 2-D data mapping technique certainly is not limited to the fuselage, hut can he very useful for many other 3-D structures.

  18. Study on Size Distributions of Airborne Particles by Aircraft Observation in Spring over Eastern Coastal Areas of China

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; LIU Hongjie; YUE Xin; LI Hong; CHEN Jianhua; TANG Dagang

    2005-01-01

    The authors studied the size distributions of particles at an altitude of 2000 m by aircraft observation over eastern costal areas of China from Zhuhai, Guangdong to Dalian, Liaoning (0.47-30 μm, 57 channels,including number concentration distribution, surface area concentration distribution and mass concentration distribution). In these cities, the average daily concentrations of PM10 are very high. They are among the most heavily polluted cities in China. The main pollution sources are anthropogenic activities such as wood, coal and oil burning. The observed size distributions show a broad spectrum and unique multi-peak characteristics, indicating no significant impacts of individual sources from urban areas. These results are far different from the distribution type at ground level. It may reflect the comprehensive effect of the regional pollution characteristics. Monitoring results over big cities could to some extent reflect their pollution characteristics.

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

    OpenAIRE

    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 ...

  20. Numerical simulation of slow spheromak formation: Flux control by formation speed

    Energy Technology Data Exchange (ETDEWEB)

    Sato, T.; Todd, A.M.M.; Okuda, H.

    1983-03-01

    Two-dimensional magnetohydrodynamic simulations of the Princeton S-1 Spheromak have been carried out for several formation speeds. It is found that the spheromak size and shape, and hence the confined poloidal and toroidal fluxes, are largely dependent upon the formation speed, provided this is moderately slow. Specifically, the total toroidal and poloidal fluxes in a spheromak increase as the formation speed is reduced. The role of externally driven reconnection as a cause for this dependence is discussed.

  1. 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.

  2. 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...... computational domain. Solutions are obtained for the acoustic field generated by a pair of corotating point vortices. Computed results are compared with the existing analytic solution for the sound field......., compressible how equations, A numerical method for the solution of the equations governing the acoustic field is presented. The primitive variable form of the governing equations is used for the numerical solution. Time integration is performed with a fourth-order, Runge-Kutta method, Discretization of the...

  3. 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.

  4. Evaluation on the structural soundness of the transport package for low-level radioactive waste for subsurface disposal against aircraft impact by finite element method

    International Nuclear Information System (INIS)

    The structural analysis of aircraft crush on the transport package for low-level radioactive waste was performed using the impact force which was already used for the evaluation of the high-level waste transport package by LSDYNA code. The transport package was deformed, and stresses due to the crush exceeded elastic range. However, plastic strains yieled in the package were far than the elongation of the materials and the body of the package did not contact the disposal packages due to the deformation of the package. Therefore, it was confirmed that the package keeps its integrity against aircraft crush. (author)

  5. Challenges in Aircraft Noise Prediction

    OpenAIRE

    Filippone A

    2014-01-01

    This contribution addresses the problem of aircraft noise prediction using theoretical methods. The problem is set in context with the needs at several levels to produce noise characterisation from commercial aircraft powered by gas turbine engines. We describe very briefly the computational model (whilst referring the reader to the appropriate literature), and provide examples of noise predictions and comparisons with measured data, where possible. We focus on the issue of stochastic analysi...

  6. 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.

  7. 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.

  8. NACA Aircraft on Lakebed - D-558-2, X-1B, and X-1E

    Science.gov (United States)

    1955-01-01

    Early NACA research aircraft on the lakebed at the High Speed Research Station in 1955: Left to right: X-1E, D-558-2, X-1B There were four versions of the original Bell X-1 rocket-powered research aircraft that flew at the NACA High-Speed Flight Research Station, Edwards, California. The bullet-shaped X-1 aircraft were built by Bell Aircraft Corporation, Buffalo, N.Y. for the U.S. Army Air Forces (after 1947, U.S. Air Force) and the National Advisory Committee for Aeronautics (NACA). The X-1 Program was originally designated the XS-1 for EXperimental Supersonic. The X-1's mission was to investigate the transonic speed range (speeds from just below to just above the speed of sound) and, if possible, to break the 'sound barrier.' Three different X-1s were built and designated: X-1-1, X-1-2 (later modified to become the X-1E), and X-1-3. The basic X-1 aircraft were flown by a large number of different pilots from 1946 to 1951. The X-1 Program not only proved that humans could go beyond the speed of sound, it reinforced the understanding that technological barriers could be overcome. The X-1s pioneered many structural and aerodynamic advances including extremely thin, yet extremely strong wing sections; supersonic fuselage configurations; control system requirements; powerplant compatibility; and cockpit environments. The X-1 aircraft were the first transonic-capable aircraft to use an all-moving stabilizer. The flights of the X-1s opened up a new era in aviation. The first X-1 was air-launched unpowered from a Boeing B-29 Superfortress on January 25, 1946. Powered flights began in December 1946. On October 14, 1947, the X-1-1, piloted by Air Force Captain Charles 'Chuck' Yeager, became the first aircraft to exceed the speed of sound, reaching about 700 miles per hour (Mach 1.06) and an altitude of 43,000 feet. The number 2 X-1 was modified and redesignated the X-1E. The modifications included adding a conventional canopy, an ejection seat, a low-pressure fuel system

  9. 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.

  10. 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.

  11. 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...

  12. Are the force characteristics of synchronous handcycling affected by speed and the method to impose power?

    NARCIS (Netherlands)

    Arnet, Ursina; van Drongelen, Stefan; Veeger, DirkJan H. E. J.; van der Woude, Lucas H. V.

    2012-01-01

    Objective: To investigate the influence of exercise conditions (speed and method to impose power) on the applied force, force effectiveness and distribution of work during handcycling. Method: Ten able-bodied men performed handcycling on a treadmill. To test the effect of speed, subjects propelled a

  13. 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.

  14. 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.

  15. Structural health monitoring and impact detection for primary aircraft structures

    Science.gov (United States)

    Kosters, Eric; van Els, Thomas J.

    2010-04-01

    The increasing use of thermoplastic carbon fiber-reinforced plastic (CFRP) materials in the aerospace industry for primary aircraft structures, such as wing leading-edge surfaces and fuselage sections, has led to rapid growth in the field of structural health monitoring (SHM). Impact, vibration, and load can all cause failure, such as delamination and matrix cracking, in composite materials. Moreover, the internal material damage can occur without being visible to the human eye, making inspection of and clear insight into structural integrity difficult using currently available evaluation methods. Here, we describe the detection of impact and its localization in materials and structures by high-speed interrogation of multiple-fiber Bragg grating (FBG) sensors mounted on a composite aircraft component.

  16. Simultaneous visual acquisition of melt jet breakup in water by high speed videography and radiography

    International Nuclear Information System (INIS)

    Motivated to understand molten corium jet falling in a water pool and fragmenting into droplets in the coolant during a hypothetical severe accident in a light water reactor (LWR), this paper presents insights on the dynamics of a coherent molten material jet and its breakup as a function of molten jet initial conditions (jet initial velocity, diameter, etc.) and material thermo-physical properties, with several corium simulant materials from low-melting temperature metallic melt (woods metal) to medium-melting temperature binary oxide melts (e.g., WO3-Bi2O3, WO3-ZrO2). A visualization system of Simultaneous High-speed Acquisition of Radiography and Photography (SHARP) is employed to quantify the characteristics of the melt jet breakup in a water pool. The experiment features well-controlled conditions and small-scale jets which can be visualized by X-ray, and therefore enables a better scrutiny of the jet breakup. (author)

  17. Calcium and voltage imaging in arrhythmia models by high-speed microscopy

    Science.gov (United States)

    de Mauro, C.; Cecchetti, C. A.; Alfieri, D.; Borile, G.; Urbani, A.; Mongillo, M.; Pavone, F. S.

    2014-03-01

    Alterations in intracellular cardiomyocyte calcium handling have a key role in initiating and sustaining arrhythmias. Arrhythmogenic calcium leak from sarcoplasmic reticulum (SR) can be attributed to all means by which calcium exits the SR store in an abnormal fashion. Abnormal SR calcium exit maymanifest as intracellular Ca2+ sparks and/or Ca2+ waves. Ca2+ signaling in arrhythmogenesis has been mainly studied in isolated cardiomyocytes and given that the extracellular matrix influences both Ca2+ and membrane potential dynamics in the intact heart and underlies environmentally mediated changes, understanding how Ca2+ and voltage are regulated in the intact heart will represent a tremendous advancement in the understanding of arrhythmogenic mechanisms. Using novel high-speed multiphoton microscopy techinques, such as multispot and random access, we investigated animal models with inherited and acquired arrhythmias to assess the role of Ca2+ and voltage signals as arrhythmia triggers in cell and subcellular components of the intact heart and correlate these with electrophysiology.

  18. 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.

  19. 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.

  20. 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.

  1. 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 ...

  2. 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.

  3. 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

  4. Special analysis of community annoyance with aircraft noise reported by residents in the vicinity of JFK Airport, 1972

    Science.gov (United States)

    Borsky, P. N.

    1975-01-01

    During the summer of 1972, about 1500 residents were interviewed twice in 11 communities near JFK airport. Detailed aircraft operations reports were also collected for this period, and an effort has been made to analyze recorded human response data in relation to a number of physical exposure parameters. A series of exposure indexes, based on an arithmetic integration of aircraft operations, were correlated with summated aircraft noise annoyance responses. None of these correlations were as good as the CNR index which assumes a logrithmetic integration of numbers of aircraft exposures and includes a day-night differential weighting of 10:1. There were substantial variations in average annoyance responses among communities with similar CNR exposures, substantiating previous findings that attitudinal and other personal variables also play an important role in determining annoyance differences.

  5. 26 CFR 48.4221-4 - Tax-free sale of articles for use by the purchaser as supplies for vessels or aircraft.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Tax-free sale of articles for use by the purchaser as supplies for vessels or aircraft. 48.4221-4 Section 48.4221-4 Internal Revenue INTERNAL REVENUE... this section, vessels engaged in sport fishing are not considered to be employed in the fisheries....

  6. Flying and handling qualities of a fly-by-wire blended-wing-body civil transport aircraft

    OpenAIRE

    de Castro, Helena V.

    2003-01-01

    The blended-wing-body (BWB) configuration appears as a promising contender for the next generation of large transport aircraft. The idea of blending the wing with the fuselage and eliminating the tail is not new, it has long been known that tailless aircraft can suffer from stability and control problems that must be addressed early in the design. This thesis is concerned with identifying and then evaluating the flight dynamics, stability, flight controls and handling qualities of a generic B...

  7. Optimization in fractional aircraft ownership

    Science.gov (United States)

    Septiani, R. D.; Pasaribu, H. M.; Soewono, E.; Fayalita, R. A.

    2012-05-01

    Fractional Aircraft Ownership is a new concept in flight ownership management system where each individual or corporation may own a fraction of an aircraft. In this system, the owners have privilege to schedule their flight according to their needs. Fractional management companies (FMC) manages all aspects of aircraft operations, including utilization of FMC's aircraft in combination of outsourced aircrafts. This gives the owners the right to enjoy the benefits of private aviations. However, FMC may have complicated business requirements that neither commercial airlines nor charter airlines faces. Here, optimization models are constructed to minimize the number of aircrafts in order to maximize the profit and to minimize the daily operating cost. In this paper, three kinds of demand scenarios are made to represent different flight operations from different types of fractional owners. The problems are formulated as an optimization of profit and a daily operational cost to find the optimum flight assignments satisfying the weekly and daily demand respectively from the owners. Numerical results are obtained by Genetic Algorithm method.

  8. 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.

  9. 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.

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

    International Nuclear Information System (INIS)

    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

  11. 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

  12. An appraisal of wind speed distribution prediction by soft computing methodologies: A comparative study

    International Nuclear Information System (INIS)

    Highlights: • Probabilistic distribution functions of wind speed. • Two parameter Weibull probability distribution. • To build an effective prediction model of distribution of wind speed. • Support vector regression application as probability function for wind speed. - Abstract: The probabilistic distribution of wind speed is among the more significant wind characteristics in examining wind energy potential and the performance of wind energy conversion systems. When the wind speed probability distribution is known, the wind energy distribution can be easily obtained. Therefore, the probability distribution of wind speed is a very important piece of information required in assessing wind energy potential. For this reason, a large number of studies have been established concerning the use of a variety of probability density functions to describe wind speed frequency distributions. Although the two-parameter Weibull distribution comprises a widely used and accepted method, solving the function is very challenging. In this study, the polynomial and radial basis functions (RBF) are applied as the kernel function of support vector regression (SVR) to estimate two parameters of the Weibull distribution function according to previously established analytical methods. Rather than minimizing the observed training error, SVRpoly and SVRrbf attempt to minimize the generalization error bound, so as to achieve generalized performance. According to the experimental results, enhanced predictive accuracy and capability of generalization can be achieved using the SVR approach compared to other soft computing methodologies

  13. 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...

  14. Variations of GHGs from the lower-troposphere to the UT/LS revealed by two Japanese regular aircraft observation programs

    Science.gov (United States)

    Niwa, Yosuke; Machida, Toshinobu; Sawa, Yousuke; Tsuboi, Kazuhiro; Matsueda, Hidekazu; Imasu, Ryoichi

    2014-05-01

    A Japan-centered observation network consisting of two regular aircraft programs have revealed the greenhouse gases variations from the lower-troposphere to the upper-troposphere/lower-stratosphere (UT/LS) regions. In the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project, in-situ continuous measurement equipment (CME) onboard commercial passenger aircraft world-widely observes CO2 profiles in vertical over tens of airports and in horizontal in the UT/LS regions. The CONTRAIL-CME has revealed three-dimensional structure of the global CO2 distribution and has exposed significant inter-hemispheric transport of CO2 through the upper-troposphere. In inverse modeling, the CME data have provided strong constraints on CO2 flux estimation especially for the Asian tropics. Automatic flask air sampling equipment (ASE) is also onboard the CONTRAIL aircraft and has been observing CO2 mixing ratios as well as those of methane, carbon monoxide, nitrous oxide and other trace species in the upper-troposphere between Japan and Australia. The observation period of the ASE has reached 20 years. In recent years, the ASE program has extended to the northern subarctic UT/LS region and has given an insight of transport mechanisms in the UT/LS by observing seasonal GHGs variations. In the other aircraft observation program by Japan Meteorological Agency, variations of GHGs have been observed by flask-sampling onboard a C-130H aircraft horizontally in the mid-troposphere over the western North Pacific as well as vertically over Minamitorishima-Island. The C-130H aircraft has persistently observed high mixing ratios of CH4 in the mid-troposphere, which seems to be originated from fossil fuel combustion throughout the year as well as from biogenic sources during summer in the Asian regions. Those above aircraft observation programs have a significant role for constraining GHGs flux estimates by filling the data gap of the existing surface measurement network

  15. Transport of north China air pollution by mid-latitude cyclones: A case study of aircraft measurements in summer 2007

    Science.gov (United States)

    Ding, A.; Wang, T.; Xue, L.; Gao, J.; Stohl, A.; Lei, H.; Jin, D.; Ren, Y.; Wang, X.; Wei, X.; Qi, Y.; Liu, J.; Zhang, X.

    2008-12-01

    Meteorological processes such as warm conveyor belts (WCBs) and frontal activities, which are related to extratropical cyclones, have been recognized to play important roles in the long-range transport of air pollutants by lifting them from the planetary boundary layer (PBL) into the free troposphere (FT) in mid- latitudes. To understand the transport mechanism and regional impact of air pollution transport in north and east China by mid-latitude cyclones in warm seasons, an aircraft study was carried out in northeast (NE) China in the summer of 2007. During a flight on 27 June, high concentrations of ozone and related trace gases as well as high values of the aerosol scattering coefficient (Bsp) were observed, with maximum concentrations (O3~ 140 ppbv, SO2 ~ 14.6 ppbv, CO ~ 1185 ppbv) recorded at an altitude of 2.6 km in the FT. In this paper we present a detailed analysis of this flight. Mesoscale meteorological simulations with the Weather Research and Forecasting (WRF) model aided the diagnostic analysis of the atmospheric dynamic structure in the low troposphere and helped in the understanding of the transport characteristics of regional and local air pollution. Based on the WRF output, a Lagrangian particle dispersion model, FLEXPART, was used to conduct backward simulations and calculate the source-receptor relationship. The study was undertaken in a region in NE China adjacent to a warm front associated with a weak cyclone in north China. Trajectory analysis and atmospheric structure analysis suggest that the aircraft sampled both the WCB and warm air frontal zone of the cyclone. The backward Lagrangian simulations show that the observed high air pollution in the FT mostly originated from the North China Plain (NCP), especially the northern part containing the megacities Beijing and Tianjin. Their plumes were vented by a stagnant front, probably through, in part, topographic lifting by the mountains in the north, and then were quickly (within 1 to 2 days

  16. Energy supply and its effect on aircraft of the future. II - Liquid-hydrogen-fueled aircraft: Prospects and design issues.

    Science.gov (United States)

    Kirkham, F. S.; Driver, C.

    1973-01-01

    The performance of hydrogen-fueled commercial aircraft is examined in the subsonic, supersonic, and hypersonic speed regime and compared with JP-fueled systems. Hydrogen aircraft are shown to provide substantial improvements in range and payload fraction as well as to minimize or eliminate many environmental problems. The major elements of a development program required to make hydrogen-fueled aircraft a commercial reality are also outlined and the rationale for and characteristics of both a subsonic demonstrator and a high speed research airplane are described.

  17. 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.

  18. 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.

  19. 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.

  20. 从飞机与高铁的瑜亮之争看交通工具的替代品威胁%Discussion on Threats of Substitute for Transportation Viewed from the Competition between Aircraft and High-speed Railway

    Institute of Scientific and Technical Information of China (English)

    李雪萍

    2016-01-01

    Toward the impact of high-speed railway transportation to aviation market in China, especially in the same routes, this paper analyzed the substitute competition between the two transportations from consumers’ point. 10 indicators including price, speed, passenger capacity, number of runs or flights per day, safety, punctuality rate, environment & service of airports/stations, environment & service in the aircraft/train, booking & refund mode (online or offline), convenience of access to airport/station, were chosen to evaluate the two transportations, with different weights according to its importance. As the result, the high-speed railway showed a relatively high score, with the example of the route Beijing-Shanghai. And the author drew a conclusion that within a 5 to 6 hours distance, the high-speed railway possesses the superiority on the ratio of performance to price to aircraft. Finally, the author gave some suggestions to the aviation such as pioneering islands air routes and expanding inland routes in China.%针对高速铁路开通后对相应飞机航线产生冲击,导致航线萎缩、停飞的现象,本文从消费者角度出发,选择了价格、速度、载客量、每日开行班次、安全性、准点率、机场/车站环境与服务、机/车内环境与服务、购退票方式、机场/车站交通接驳便利度等10个指标,并按照重要程度为各指标赋予权重,以京沪线为例,对两种交通工具进行了比较。结果是高铁以相对优势胜出。从而得出结论:在运行时间5-6小时区间内,高铁在性价比上占优,飞机只能立足于更远程的运输市场。同时对飞机运输提出了开辟海岛航线和加大中西部航线等发挥自身优势的建议。

  1. A Brief Study of the Speed Reduction of Overtaking Airplanes by Means of Air Brakes, Special Report

    Science.gov (United States)

    Pearson, H. A.; Amderspm. R. F.

    1942-01-01

    As an aid to airplane designers interested in providing pursuit airplanes with decelerating devices intended to increase the firing time when overtaking another airplane, formulas are given relating the pertinent distances and speeds in horizontal flight to the drag increase required. Charts are given for a representative parasite-drag coefficient from which the drag increase, the time gained, and the closing distance may be found. The charts are made up for three values of the ratio of the final speed of the pursuing airplane to the speed of the pursued airplane and for several values of the ratio of the speed of the pursued airplane to the initial speed of the pursuing airplane. Charts are also given indicating the drag increases obtainable with double split flaps and with conventional propellers. The use of the charts is illustrated by an example in which it is indicated that either double split flaps or, under certain ideal conditions, reversible propellers should provide the speed reductions required.

  2. 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.

  3. 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.

  4. 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.

  5. 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,...

  6. 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...

  7. 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...

  8. 14 CFR 25.33 - Propeller speed and pitch limits.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Propeller speed and pitch limits. 25.33 Section 25.33 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight General § 25.33 Propeller speed and pitch limits. (a) The propeller speed and...

  9. Rapid isolation and purification of phorbol esters from Jatropha curcas by high-speed countercurrent chromatography.

    Science.gov (United States)

    Hua, Wan; Hu, Huiling; Chen, Fang; Tang, Lin; Peng, Tong; Wang, Zhanguo

    2015-03-18

    In this work, a high-speed countercurrent chromatography (HSCCC) method was established for the preparation of phorbol esters (PEs) from Jatropha curcas. n-Hexane-ethyl acetate-methanol-water (1.5:1.5:1.2:0.5, v/v) was selected as the optimum two-phase solvent system to separate and purify jatropha factor C1 (JC1) with a purity of 85.2%, as determined by HPLC, and to obtain a mixture containing four or five PEs. Subsequently, continuous semipreparative HPLC was applied to further purify JC1 (99.8% as determined by HPLC). In addition, UPLC-PDA and UPLC-MS were established and successfully used to evaluate the isolated JC1 and PE-rich crude extract. The purity of JC1 was only 87.8% by UPLC-UV. A peak (a compound highly similar to JC1) was indentified as the isomer of JC1 by comparing the characteristic UV absorption and MS spectra. Meanwhile, this strategy was also applied to analyze the PE-rich crude extract from J. curcas. It is interesting that there may be more than 15 PEs according to the same quasi-molecular ion peaks, highly similar sequence-specific fragment ions, and similar UV absorption spectrum. PMID:25686848

  10. 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).

  11. Improving conducting polymer electrochromic speeds and depositing aligned polymeric nanofibers by electrospinning process

    Science.gov (United States)

    Asemota, Chris I.

    The effects of film thickness and porosity on electrochromic switching time of conducting polymers was pursued to determine the morphology influence on ions transport during oxidation step of the redox process, affording sub-second or seconds switching times. Electrospinning technique provided non-woven nanofiber mats, while spin coating and electropolymerization of monomer (N3T) provided films. Porosity decreased as depositing method changed from electrospinning to spin coating. In electrochemical oxidation, the electrons leave the polymer at the metal electrode-polymer film interface, and counter ions arrive at the polaron-bipolaron sites left in the polymer, through polymer-electrolyte interface. Counter ion diffusion in conducting polymers are film thickness limited at increasing thickness and inability of ions to reach holes sites on the oxidizing polymer accounts for long switching speeds, introducing extensive and micro pores and high surface areas should lead to decreasing electrochromic switching speed to single digit time in seconds (for display and vision applications), while increasing the maximum optical switching contrast due to increased fiber mat thicknesses. Photolithographic patterning of nanofiber mats of the conducting polymer precursor having photo cross-linking unit was also explored. The photo-crosslinkable polymer was prepared by including norborene methacrylate (NMA) units to the polymer backbone during precursor polymerization, yielding a terpolymer poly(N3T-NA-NMA). The influence of photo crosslinking on electrochemical switching in conducting polymer nanofibers, and effect of developing parameters (solvent and time) on pattern transfer to the nanofiber mat was investigated and showed no influence on the electrochemical redox of the polymer. Solvents suitable for dissolving the polymer were investigated as developers with results showing non-differentiable pattern transfer for all suitable solvents, and no net preference to solvent choice

  12. 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

  13. 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.

  14. 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.

  15. Positron annihilation lifetime in Fe-Rh alloys deformed by high-speed compression

    Energy Technology Data Exchange (ETDEWEB)

    Fukuzumi, M. [Graduate School of Engineering, Osaka Prefecture Univ., Sakai (Japan); Hori, F.; Oshima, R. [Research Inst. for Advanced Science and Technology, Osaka Prefecture Univ., Sakai (Japan); Komatsu, M.; Kiritani, M. [Research Center for Ultra-High-Speed Plastic Deformation, Hiroshima Inst. of Tech., Saekiku (Japan)

    2001-07-01

    In order to examine the role of structural vacancies in the stress-induced phase transitions of B2-type FeRh alloys, Fe-40, 45 and 50 at%Rh specimens were deformed at room temperature with a high-speed compression machine and were studied by X-ray diffractometry (XRD) and positron annihilation measurements. It was found from the positron lifetime results that vacancies or vacancy clusters were introduced into the alloy by deformation. The longer lifetime ({tau}{sub 2}) components were changed with the deformation momenta and Rh concentrations. In the case of Fe-50 at%Rh, they were 188 ps and 254 ps after deformation with small or large momenta, respectively. Taking the X-ray results into consideration, it is concluded that an atom movement mechanism forming large vacancy clusters is associated with the B2-A1 transition. The short lifetime ({tau}{sub 1}) of the alloy is accounted for by bulk annihilation in the transformed phases and a high density of dislocations. (orig.)

  16. 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

  17. Fetal lung volume measurement by MRI with high-speed imaging systems

    Energy Technology Data Exchange (ETDEWEB)

    Osada, Hisao; Kaku, Kenshi [Chiba Univ. (Japan). Hospital

    2002-08-01

    Although ultrasonography is widely used for fetal morphologic observation, magnetic resonance imaging (MRI) has gained popularity as a new prenatal diagnostic method with recent introduction of high-speed imaging systems. Infants with lung hypoplasia affecting respiratory function require intensive management starting immediately after birth. Therefore, accurate prenatal differential diagnosis and severity evaluation are extremely important for these fetuses. The aim of this study is to measure fetal lung volume using a computer-based, three-dimensional MRI imaging system and to evaluate the possibility of clinical applications of this procedure. A total of 96 fetuses were evaluated, all were morphologically abnormal, and MRI was done for advanced assessment from 24 to 39 weeks gestation. Three-directional views of fetal chest were imaged by Signa Horizon, 1.5 Tesla, version 5.6 (General Electronics) with the following conditions; coil: TORSO coil, sequence: SSFSE (single shot fast spin echo), slice thickness: 5 mm, and imaging speed: 2 seconds/slice. To calculate the lung volume and create three-dimensional image, the lung area in each slice was traced out, then multiplied using computer image processing. Simultaneously, the volumes of all slices were summed to give the volume of each lung. Linear regression analysis and analysis of covariance (ANCOVA) were used for statistical analyses. In all cases, clear images were obtained, and were adequate for three-dimensional evaluation of the fetal lung. Thirty-five fetuses had poor outcomes, such as intrauterine fetal death, neonatal death, and intensive respiratory care. Regression lines of lung volume versus gestational week were calculated for these fetuses with poor outcome and 61 other fetuses with good outcome. ANCOVA, with gestational week as a covariant, revealed a significant intergroup difference in the lung volume (p<0.001). Similarly, regression lines of lung volume versus fetal body weight estimated by

  18. Fetal lung volume measurement by MRI with high-speed imaging systems

    International Nuclear Information System (INIS)

    Although ultrasonography is widely used for fetal morphologic observation, magnetic resonance imaging (MRI) has gained popularity as a new prenatal diagnostic method with recent introduction of high-speed imaging systems. Infants with lung hypoplasia affecting respiratory function require intensive management starting immediately after birth. Therefore, accurate prenatal differential diagnosis and severity evaluation are extremely important for these fetuses. The aim of this study is to measure fetal lung volume using a computer-based, three-dimensional MRI imaging system and to evaluate the possibility of clinical applications of this procedure. A total of 96 fetuses were evaluated, all were morphologically abnormal, and MRI was done for advanced assessment from 24 to 39 weeks gestation. Three-directional views of fetal chest were imaged by Signa Horizon, 1.5 Tesla, version 5.6 (General Electronics) with the following conditions; coil: TORSO coil, sequence: SSFSE (single shot fast spin echo), slice thickness: 5 mm, and imaging speed: 2 seconds/slice. To calculate the lung volume and create three-dimensional image, the lung area in each slice was traced out, then multiplied using computer image processing. Simultaneously, the volumes of all slices were summed to give the volume of each lung. Linear regression analysis and analysis of covariance (ANCOVA) were used for statistical analyses. In all cases, clear images were obtained, and were adequate for three-dimensional evaluation of the fetal lung. Thirty-five fetuses had poor outcomes, such as intrauterine fetal death, neonatal death, and intensive respiratory care. Regression lines of lung volume versus gestational week were calculated for these fetuses with poor outcome and 61 other fetuses with good outcome. ANCOVA, with gestational week as a covariant, revealed a significant intergroup difference in the lung volume (p<0.001). Similarly, regression lines of lung volume versus fetal body weight estimated by

  19. Investigation of Flow Instabilities in the Inlet Ducts of DP-1C VTOL Aircraft

    Science.gov (United States)

    Lepicovsky, Jan

    2008-01-01

    An investigation of flow instabilities in the inlet ducts of a two-engine vertical takeoff and landing aircraft DP-1C is described in this report. Recent tests revealed that the engines stall during run ups while the aircraft is operating on the ground. These pop stalls occurred at relatively low power levels, sometimes as low as 60 percent of the engine full speed. Inability to run the engines up to the full speed level is attributed to in-ground effects associated with hot gas ingestion. Such pop stalls were never experienced when the aircraft was tested on a elevated grid platform, which ensured that the aircraft was operating in out-of-the-ground-effect conditions. Based on available information on problems experienced with other vertical takeoff and landing aircraft designs, it was assumed that the engine stalls were caused by partial ingestion of hot gases streaming forward from the main exit nozzle under the aircraft inlets, which are very close to the ground. It was also suggested that the nose wheel undercarriage, located between the inlets, may generate vortices or an unstable wake causing intense mixing of hot exit gases with incoming inlet flow, which would enhance the hot gas ingestion. After running a short three-day series of tests with fully instrumented engine inlets, it is now believed the most probable reason for engine pop stalls are random ingestions of a vortex generated between the two streams moving in opposite directions: outbound hot gas stream from the main nozzle close to the ground and inbound inlet flow above. Originally, the vortex is in a horizontal plane. However, at a certain velocity ratio of these two streams, the vortex attaches either to the ground or the aircraft surface at one end and the other end is swallowed by one of the aircraft inlets. Once the vortex enters the inlet duct, a puff of hot air can be sucked through the vortex core into the engine, which causes a serious inlet flow field distortion followed by an engine

  20. 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.

  1. Controlling and Reducing of Speed for Vehicles Automatically By Using Rf Technology.

    Directory of Open Access Journals (Sweden)

    Y. Ravindra Babu,

    2014-11-01

    Full Text Available For vehicle safety and safety for passengers in vehicle is an important parameter. Most of the vehicles get accident because no proper safety measures are taken especially at curves and hair pin bends humps and any obstacles in front of the vehicle. This system can be used for the prevention of such a problem by indicating a pre indication and also reducing the speed of vehicles by reducing the fuel rate of vehicle. As the action is in terms of fuel rate so the vehicle automatically goes to control and avoids the accidents. At curves and hair pin bends the line of sight is not possible for the drivers so the special kind of transmitter which is tuned at a frequency of 433MHZ are mounted as these transmitters continuously radiate a RF signal for some particular area. As the vehicle come within this radiation the receiver in the vehicle gets activate. The transmitter used here is a coded transmitter which is encoded with encoder. The encoder provides a 4 bit binary data which is serially transmitted to transmitter. The transmitter used here is ASK type (amplitude shift keying which emits the RF radiation.

  2. 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.

  3. High-speed DNA-based rolling motors powered by RNase H

    Science.gov (United States)

    Yehl, Kevin; Mugler, Andrew; Vivek, Skanda; Liu, Yang; Zhang, Yun; Fan, Mengzhen; Weeks, Eric R.; Salaita, Khalid

    2016-02-01

    DNA-based machines that walk by converting chemical energy into controlled motion could be of use in applications such as next-generation sensors, drug-delivery platforms and biological computing. Despite their exquisite programmability, DNA-based walkers are challenging to work with because of their low fidelity and slow rates (˜1 nm min-1). Here we report DNA-based machines that roll rather than walk, and consequently have a maximum speed and processivity that is three orders of magnitude greater than the maximum for conventional DNA motors. The motors are made from DNA-coated spherical particles that hybridize to a surface modified with complementary RNA; the motion is achieved through the addition of RNase H, which selectively hydrolyses the hybridized RNA. The spherical motors can move in a self-avoiding manner, and anisotropic particles, such as dimerized or rod-shaped particles, can travel linearly without a track or external force. We also show that the motors can be used to detect single nucleotide polymorphism by measuring particle displacement using a smartphone camera.

  4. High speed production of YBCO precursor films by advanced TFA-MOD process

    International Nuclear Information System (INIS)

    YBa2Cu3O7-y (YBCO) long tapes derived from the metal-organic deposition (MOD) method using the starting solution containing trifluoroacetate (TFA) have been developed with high critical currents (Ic) over 200 A/cm-width. However, high speed production of YBCO films is simultaneously necessary to satisfy the requirements of electric power device applications in terms of cost and the amounts of the tapes. In this work, we developed a new TFA-MOD starting solution using F-free salt of Y, TFA salt of Ba and Cu-Octylate for application to the coating/calcination process and discussed several issues by using the Multi-turn (MT) Reel-to-Reel (RTR) system calcination furnace for the purpose of high throughput without degradation of the properties. The coating system was improved for uniform deposition qualities in both longitudinal and transversal directions. YBCO films using the new starting solution at the traveling rate of 10 m/h in coating/calcination by the MT-RTR calcination furnace showed the values of the critical current density of 1.6 MA/cm2 as thick as 1.5 μm at 77 K under the self fields after firing at the high heating rate in the crystallization.

  5. High-speed DNA-based rolling motors powered by RNase H.

    Science.gov (United States)

    Yehl, Kevin; Mugler, Andrew; Vivek, Skanda; Liu, Yang; Zhang, Yun; Fan, Mengzhen; Weeks, Eric R; Salaita, Khalid

    2016-02-01

    DNA-based machines that walk by converting chemical energy into controlled motion could be of use in applications such as next-generation sensors, drug-delivery platforms and biological computing. Despite their exquisite programmability, DNA-based walkers are challenging to work with because of their low fidelity and slow rates (∼1 nm min(-1)). Here we report DNA-based machines that roll rather than walk, and consequently have a maximum speed and processivity that is three orders of magnitude greater than the maximum for conventional DNA motors. The motors are made from DNA-coated spherical particles that hybridize to a surface modified with complementary RNA; the motion is achieved through the addition of RNase H, which selectively hydrolyses the hybridized RNA. The spherical motors can move in a self-avoiding manner, and anisotropic particles, such as dimerized or rod-shaped particles, can travel linearly without a track or external force. We also show that the motors can be used to detect single nucleotide polymorphism by measuring particle displacement using a smartphone camera. PMID:26619152

  6. 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.

  7. IPS Observations at 140 MHz to Study Solar Wind Speeds and Density Fluctuations by MEXART.

    Science.gov (United States)

    Gonzalez-Esparza, A.; Chang, O.; Mejia-Ambriz, J. C.

    2015-12-01

    The interplanetary scintillation (IPS) technique is a remote-sensing method for monitoring the inner heliosphere. These observations supply information on solar wind conditions covering heliocentric ranges that no other technique can provide. The Mexican Array Radio Telescope (MEXART) is a single-station instrument operating at 140 MHz, fully dedicated to perform solar-wind studies employing the IPS technique. We present MEXART solar-wind measurements (scintillation indices and solar-wind speeds), reporting the first observations of four IPS sources (3C273, 3C283, 3C286, 3C298) detected by MEXART during October-December 2014. We present the first MEXART measurements of the transit of an IPS radio source (3C298) from weak to strong scattering regions, and the initial MEXART heliographic maps of solar wind conditions. The MEXART observations will complement the solar wind IPS studies using other frequencies, and the tracking of solar wind disturbances by other stations located at different longitudes. These solar wind measurements, provided in real time, can have space weather forecasting applications.

  8. 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.

  9. Atomization of a small-diameter liquid jet by a high-speed gas stream

    Science.gov (United States)

    Varga, Christopher Michael

    The situation of a small-diameter liquid jet exposed to a large-diameter high-speed gas jet is investigated experimentally. Flow visualization and particle-sizing techniques are employed to examine both the initial breakup process and subsequent secondary atomization of the liquid. It is shown that nearly all of the breakup takes place in the near-field and that the bulk of the atomization is completed within the potential cone of the gas jet. The resultant drop size depends primarily on the gas velocity and to a weaker extent on the liquid mass flux. It is argued that the mechanism of primary atomization is similar to that of a liquid drop suddenly exposed to a high-speed gas stream. A phenomenological breakup model is proposed for the initial droplet size, based on the accelerative destabilization of the liquid jet surface by the Rayleigh-Taylor instability. Measurements of droplet sizes and surface wavelengths are shown to be in good agreement with the model predictions. The downstream evolution of the droplet-size distribution is also investigated, with consideration given to several secondary mechanisms including turbulent breakup, droplet-droplet collisions, and droplet acceleration. It is argued that the relative acceleration of droplets of different size classes, and energetic collisions between droplets, are together responsible for the experimentally observed variation of the mean drop size with downstream distance from the injection plane in the far-field of the spray. The feasibility of coaxial liquid-gas injection for pulse detonation engine (PDE) applications is additionally considered. The performance of coaxial atomizers under transient operating conditions appropriate to PDEs is analyzed along with the capability of this injection scheme to produce sufficiently small droplet sizes within restricted flow regimes. The ability to tailor the radial distributions of both the liquid mass flux and droplet sizes through the addition of swirl to the coaxial

  10. Policy and the evaluation of aircraft noise

    OpenAIRE

    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 distribution of the frames in the population is dependent on structural variables related to the individual. To reveal subjects’ frames of aircraft noise a latent class model is estimated based on ...

  11. Challenges for the aircraft structural integrity program

    Science.gov (United States)

    Lincoln, John W.

    1994-01-01

    Thirty-six years ago the United States Air Force established the USAF Aircraft Structural Integrity Program (ASIP) because flight safety had been degraded by fatigue failures of operational aircraft. This initial program evolved, but has been stable since the issuance of MIL-STD-1530A in 1975. Today, the program faces new challenges because of a need to maintain aircraft longer in an environment of reduced funding levels. Also, there is increased pressure to reduce cost of the acquisition of new aircraft. It is the purpose of this paper to discuss the challenges for the ASIP and identify the changes in the program that will meet these challenges in the future.

  12. Measured speed versus true speed

    OpenAIRE

    Perez, Israel

    2010-01-01

    The theoretical predictions, derived from the Lorentz and the Tangherlini transformations, for the one-way speed of any physical entity are confronted with the corresponding expressions for the one-way measured speed obtained from a gedanken experiment. The experiment demonstrates that, for an inertial frame $K'$ in motion relative to an inertial frame $K$ where the one-way speed of light is isotropic, even the special theory of relativity renders the one-way speed of light as function of the...

  13. 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.

  14. Chaotic Dynamics of High Speed Rotating Shaft Supported by Ball Bearings Due to Distributed Defects

    Directory of Open Access Journals (Sweden)

    S. H. Upadhyay ,

    2010-10-01

    Full Text Available This paper presents a mathematical model to investigate the nonlinear dynamic behavior of a high speed rotorbearing system due to varying the number of rolling elements. Two cases one without race defect and one with defect as race waviness have been studied. In the formulation, the contacts between rolling elements and inner/outerraces are considered as nonlinear springs and also used nonlinear damping, which is developed by correlating the contact damping force with the equivalent contact stiffness and contact deformation rate. The equations of motion are formulated using Lagrange’s equation, considering the vibration characteristics of the individual componentssuch as inner race, outer race, rolling elements and rotor. For non-defective bearings, nonlinear dynamic responses are found to be associated with ball passage frequency ( bp  . For defective bearings, nonlinear dynamic responses are found to be associated mainly with wave passage frequency ( wp  and also with the interactive effect of wave passage and ball passage frequencies. The wave-number (Nw of waviness and number of balls (Nb are importantparameters of study because even if these are inevitable, these can be controlled the system nature to a good extent.

  15. Speed regulation of water turbines by status feedback; Drehzahlregelung von Wasserturbinen mit Zustandsreglern

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, W.

    1990-12-31

    The development of a speed controller by state freedback for water turbines will be presented. The possible improvement of the dynamic behaviour of the whole hydro power plant will be shown. The interaction of automatic control with the system and the influence of real working conditions will be described in detail. The procedure of controller design and the development of the description of the system in state equations will be explained. In addition to this the development of a digital program for the nonlinear simulation of hydro power plants will be presented. (orig.) [Deutsch] Die Entwicklung eines Zustandsreglers fuer die Drehzahlregelung von Wasserturbinen wird vorgestellt. Anhand nichtlinerer Simulationen wird die damit erzielbare Verbesserung des dynamischen Verhaltens der gesamten Wasserkraftanlage dokumentiert, sowie das Zusammenwirken mit regelungsnahen Steuerungen und der Einfluss praktischer Randbedingungen detailliert untersucht. Die Vorgehensweise beim Reglerentwurf und bei der Erstellung der dazu notwendigen linearen Beschreibung des dynamischen Verhaltens wird erlaeutert. Darueber hinaus wird die Entwicklung eines Programmsystems zur nichtlinearen Simulation von Wasserkraftanlagen beschrieben. (orig.)

  16. 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.

  17. IPS observations at 140 MHz to study solar wind speeds and density fluctuations by MEXART

    Science.gov (United States)

    Chang, Oyuki; Gonzalez-Esparza, J. A.; Mejia-Ambriz, J.

    2016-03-01

    The interplanetary scintillation (IPS) technique is a remote-sensing method for monitoring the inner heliosphere. These observations supply information on solar wind conditions covering heliocentric ranges that no other technique can provide. The Mexican Array Radio Telescope (MEXART) is a single-station instrument operating at 140 MHz, fully dedicated to performing solar-wind studies employing the IPS technique. We present solar-wind parameters (scintillation indices and solar-wind speeds), using the initial measurements from this array of four IPS sources (3C273, 3C283, 3C286, 3C298) detected during October-December 2014. We report the transit of an IPS radio source (3C298), observed at 140 MHz, from weak- to strong-scattering regions at around 0.36 AU, and sky projection maps of solar wind conditions associated presumably with the passing of one or more Coronal Mass Ejections (CMEs). These results show the progress to operate the full array in the near future. The MEXART observations will complement the solar wind IPS studies using other frequencies, and the tracking of solar wind disturbances by other stations located at different longitudes. These solar wind measurements, provided in real time, can have space-weather forecasting applications.

  18. 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.

  19. Forward Looking Radar Imaging by Truncated Singular Value Decomposition and Its Application for Adverse Weather Aircraft Landing

    Directory of Open Access Journals (Sweden)

    Yulin Huang

    2015-06-01

    Full Text Available The forward looking radar imaging task is a practical and challenging problem for adverse weather aircraft landing industry. Deconvolution method can realize the forward looking imaging but it often leads to the noise amplification in the radar image. In this paper, a forward looking radar imaging based on deconvolution method is presented for adverse weather aircraft landing. We first present the theoretical background of forward looking radar imaging task and its application for aircraft landing. Then, we convert the forward looking radar imaging task into a corresponding deconvolution problem, which is solved in the framework of algebraic theory using truncated singular decomposition method. The key issue regarding the selecting of the truncated parameter is addressed using generalized cross validation approach. Simulation and experimental results demonstrate that the proposed method is effective in achieving angular resolution enhancement with suppressing the noise amplification in forward looking radar imaging.

  20. Forward Looking Radar Imaging by Truncated Singular Value Decomposition and Its Application for Adverse Weather Aircraft Landing.

    Science.gov (United States)

    Huang, Yulin; Zha, Yuebo; Wang, Yue; Yang, Jianyu

    2015-01-01

    The forward looking radar imaging task is a practical and challenging problem for adverse weather aircraft landing industry. Deconvolution method can realize the forward looking imaging but it often leads to the noise amplification in the radar image. In this paper, a forward looking radar imaging based on deconvolution method is presented for adverse weather aircraft landing. We first present the theoretical background of forward looking radar imaging task and its application for aircraft landing. Then, we convert the forward looking radar imaging task into a corresponding deconvolution problem, which is solved in the framework of algebraic theory using truncated singular decomposition method. The key issue regarding the selecting of the truncated parameter is addressed using generalized cross validation approach. Simulation and experimental results demonstrate that the proposed method is effective in achieving angular resolution enhancement with suppressing the noise amplification in forward looking radar imaging. PMID:26094627

  1. 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.

  2. 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.

  3. 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.

  4. DESCRIPTION OF THE MANAGEMENT TASK OF PROVIDING QUALIFIED HUMAN RESOURCES TO RUSSIAN AIRCRAFT INDUSTRIAL ENTERPRISES BY THE UNIVERSITIES

    Directory of Open Access Journals (Sweden)

    Chernov Vasily Mikhaylovich

    2013-05-01

    Full Text Available The paper describes the organizational and economic mechanism for providing the qualified human resources to the enterprises of Russian Aviation Industrial Complex by the universities. The author focuses on forming a system of general assumptions, choosing the management object, the subject area, the operating parties, and the subject of control; forming the objectives of the operating parties; choosing the management purposes, a set of management actions, the external impacts on the management object except for the management actions; identifying inadmissible conditions of the control object and inadmissible administrative impacts on the control object. In terms of content the management task of providing qualified human resources to Russian aircraft industrial enterprises is to identify and justify the need to improve the human resource capacity of an entity so as to ensure maximum achievement of the set management objectives in the presence of external influences that do not result in an unacceptable state of the management object and do not exceed the allowable area of ​​management.

  5. 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.

  6. Microstructure evolution of eutectic Al-Cu strips by high-speed twin-roll strip casting process

    Science.gov (United States)

    Sahoo, Seshadev; Ghosh, Sudipto

    2015-10-01

    In the present investigation, microstructural evolutions of functionally graded eutectic Al-Cu strips prepared by high-speed twin-roll strip caster at different casting speeds and liquid melt superheats were studied. The as-cast sample was subjected to scanning electron microscope to study the evolution of microstructure of the strip at different casting speeds and liquid melt superheats. At different casting speeds, non-equilibrium eutectic structure observed on the Al-Cu eutectic strip consists of lamellar as well as wavy structure with a distinct boundary. The lamellar microstructure consists of alternating layers of well-bonded α-Al phase and θ-Al2Cu phase. The globular flowery structure within the eutectic matrix was observed on the strip at different liquid melt superheats. The microhardness of the as-cast strip was studied by Vickers hardness tester, and it was found that hardness value increases with increasing casting speed and decreases with increasing liquid melt superheat.

  7. 77 FR 20012 - Federal Acquisition Regulation; Information Collection; Corporate Aircraft Costs

    Science.gov (United States)

    2012-04-03

    ... Regulation; Information Collection; Corporate Aircraft Costs AGENCY: Department of Defense (DOD), General... collection requirement concerning corporate aircraft costs. Public comments are particularly invited on..., Corporate Aircraft Costs, by any of the following methods: Regulations.gov :...

  8. Model Assessment of the Impact on Ozone of Subsonic and Supersonic Aircraft

    Science.gov (United States)

    Ko, Malcolm; Weisenstein, Debra; Danilin, Michael; Scott, Courtney; Shia, Run-Lie

    2000-01-01

    This is the final report for work performed between June 1999 through May 2000. The work represents continuation of the previous contract which encompasses five areas: (1) continued refinements and applications of the 2-D chemistry-transport model (CTM) to assess the ozone effects from aircraft operation in the stratosphere; (2) studying the mechanisms that determine the evolution of the sulfur species in the aircraft plume and how such mechanisms affect the way aircraft sulfur emissions should be introduced into global models; (3) the development of diagnostics in the AER 3-wave interactive model to assess the importance of the dynamics feedback and zonal asymmetry in model prediction of ozone response to aircraft operation; (4) the development of a chemistry parameterization scheme in support of the global modeling initiative (GMI); and (5) providing assessment results for preparation of national and international reports which include the "Aviation and the Global Atmosphere" prepared by the Intergovernmental Panel on Climate Change, "Assessment of the effects of high-speed aircraft in the stratosphere: 1998" by NASA, and the "Model and Measurements Intercomparison II" by NASA. Part of the work was reported in the final report. We participated in the SAGE III Ozone Loss and Validation Experiment (SOLVE) campaign and we continue with our analyses of the data.

  9. Development of an ultrasonic pulse-echo (UPE) technique for aircraft icing studies

    Science.gov (United States)

    Liu, Yang; Chen, Wen-Li; Bond, Leonard J.; Hu, Hui

    2014-02-01

    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.

  10. Development of an ultrasonic pulse-echo (UPE) technique for aircraft icing studies

    International Nuclear Information System (INIS)

    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

  11. 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.

  12. Advanced control for airbreathing engines, volume 2: General Electric aircraft engines

    Science.gov (United States)

    Bansal, Indar

    1993-01-01

    The application of advanced control concepts to air breathing engines may yield significant improvements in aircraft/engine performance and operability. Screening studies of advanced control concepts for air breathing engines were conducted by three major domestic aircraft engine manufacturers to determine the potential impact of concepts on turbine engine performance and operability. The purpose of the studies was to identify concepts which offered high potential yet may incur high research and development risk. A target suite of proposed advanced control concepts was formulated and evaluated in a two phase study to quantify each concept's impact on desired engine characteristics. To aid in the evaluation specific aircraft/engine combinations were considered: a Military High Performance Fighter mission, a High Speed Civil Transport mission, and a Civil Tiltrotor mission. Each of the advanced control concepts considered in the study are defined and described. The concept potential impact on engine performance was determined. Relevant figures of merit on which to evaluate the concepts are determined. Finally, the concepts are ranked with respect to the target aircraft/engine missions. A final report describing the screening studies was prepared by each engine manufacturer. Volume 2 of these reports describes the studies performed by GE Aircraft Engines.

  13. 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.

  14. 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

  15. Increasing the rewriting speed of optical rewritable e-paper by selecting proper liquid crystals

    Institute of Scientific and Technical Information of China (English)

    Geng Yu; Sun Jiatong; Anatoli Murauski; Vladimir Chigrinov; Kwok Hoi Sing

    2012-01-01

    The effect of interaction between liquid crystal (LC) and photoalignment material on the speed of optical rewriting process is investigated.The theoretical analysis shows that a smaller frank elastic constant K22 of liquid crystal corresponds to a larger twist angle,which gives rise to a larger rewriting speed.Six different LC cells with the same boundary conditions (one substrate is covered with rubbed polyimide (PI) and the other with photo sensitive rewritable sulfuric dye 1(SD1)) are tested experimentally under the same illumination intensity (450 nm,80 mW/cm2).The results demonstrate that with a suitable liquid crystal,the LC optical rewriting speed for e-paper application can be obviously improved.For two well known LC materials E7 (K22 is larger) and 5CB (K22 is smaller),they require 11 s and 6 s corresponding to change alignment direction for generating image information.

  16. Increasing the rewriting speed of optical rewritable e-paper by selecting proper liquid crystals

    Science.gov (United States)

    Geng, Yu; Sun, Jiatong; Anatoli, Murauski; Vladimir, Chigrinov; Kwok Hoi, Sing

    2012-08-01

    The effect of interaction between liquid crystal (LC) and photoalignment material on the speed of optical rewriting process is investigated. The theoretical analysis shows that a smaller frank elastic constant K22 of liquid crystal corresponds to a larger twist angle, which gives rise to a larger rewriting speed. Six different LC cells with the same boundary conditions (one substrate is covered with rubbed polyimide (PI) and the other with photo sensitive rewritable sulfuric dye 1(SD1)) are tested experimentally under the same illumination intensity (450 nm, 80 mW/cm2). The results demonstrate that with a suitable liquid crystal, the LC optical rewriting speed for e-paper application can be obviously improved. For two well known LC materials E7 (K22 is larger) and 5CB (K22 is smaller), they require 11 s and 6 s corresponding to change alignment direction for generating image information.

  17. Effect of car speed on amount of air supplied by ventilation system to the space of car cabin

    Science.gov (United States)

    Fišer, Jan; Pokorný, Jan

    2014-03-01

    The amount of air supplied by ventilation system (HVAC system) of a car into a cabin is one of the main parameters for the correct simulation and prediction of a car cabin heat load. This amount is not based only on the current setting of the HVAC system, but also on the actual operating conditions and speed of the car. The authors therefore carried out experiments in the cabin of a passenger car in real traffic, while observing the amount of air on the speed of the car and setting of flap in mixing chamber. In a subsequent analysis the authors defined dependence of the airflow rate supplied by HVAC system on the speed of the car. Obtained empirical formulas were then used as a part of the code which calculates the data for the HVAC boundary conditions in the simulation of the car cabin environment.

  18. Effect of car speed on amount of air supplied by ventilation system to the space of car cabin

    Directory of Open Access Journals (Sweden)

    Fišer Jan

    2014-03-01

    Full Text Available The amount of air supplied by ventilation system (HVAC system of a car into a cabin is one of the main parameters for the correct simulation and prediction of a car cabin heat load. This amount is not based only on the current setting of the HVAC system, but also on the actual operating conditions and speed of the car. The authors therefore carried out experiments in the cabin of a passenger car in real traffic, while observing the amount of air on the speed of the car and setting of flap in mixing chamber. In a subsequent analysis the authors defined dependence of the airflow rate supplied by HVAC system on the speed of the car. Obtained empirical formulas were then used as a part of the code which calculates the data for the HVAC boundary conditions in the simulation of the car cabin environment.

  19. 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

  20. Preparative isolation and purification of flavonoids from the Chinese medicinal herb Belamcanda by high-speed countercurrent chromatography

    OpenAIRE

    Peng, Cuilin; Liang, Yong; Wang, Xiaohong; Xie, Huichun; Zhang, Tianyou; Ito, Yoichiro

    2009-01-01

    High-speed countercurrent chromatography (HSCCC) was applied for separation and purification of flavonoids from the extract of belamcanda. High efficiency of HSCCC separation was achieved on a two-phase solvent system of n-hexane–ethyl acetate–methanol–water (4:5:5:5, v/v) by eluting the lower mobile phase at a flow-rate of 1.2mL/min and a revolution speed of 800 rpm. Three well-separated peaks were obtained in the HSCCC chromatogram and their purities were determined by HPLC-UV absorption sp...

  1. Experimental investigation of the cornering of a C40 x 14-21 cantilever aircraft tire

    Science.gov (United States)

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

    1973-01-01

    An experimental investigation was conducted at the Langley aircraft landing loads and traction facility to define the cornering characteristics of a size C40 x14-21 aircraft tire of cantilever design. 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 of 5 to 100 knots, both with and without braking. The results of this investigation show that the cornering-force and drag-force friction coefficients and self-alining torque were influenced by the yaw angle, ground speed, brake torque, surface wetness, and the locked-wheel condition.

  2. 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.  

  3. An evaluation of the performance of chemistry transport models by comparison with research aircraft observations. Part 1: Concepts and overall model performance

    OpenAIRE

    Brunner, D.; Staehelin, J; Rogers, H. L.; Köhler, M. O.; Pyle, J.A.; Hauglustaine, D.; Jourdain, L.; Berntsen, T. K.; Gauss, M.; I. S. A. Isaksen; MEIJER E.; Van Velthoven, P.; Pitari, G.; Mancini, E; Grewe, V

    2003-01-01

    A rigorous evaluation of five global Chemistry-Transport and two Chemistry-Climate Models operated by several different groups in Europe was performed by comparing the models with trace gas observations from a number of research aircraft measurement campaigns. Whenever possible the models were run over the four-year period 1995–1998 and at each simulation time step the instantaneous tracer fields were interpolated to all coinciding observation points. This approach allows for a ...

  4. An evaluation of the performance of chemistry transport models by comparison with research aircraft observations. Part 1: Concepts and overall model performance

    OpenAIRE

    Brunner, D.; Staehelin, J; Rogers, H. L.; Köhler, M. O.; Pyle, J.A.; Hauglustaine, D.; Jourdain, L.; Berntsen, T. K.; Gauss, M.; I. S. A. Isaksen; MEIJER E.; Van Velthoven, P.; Pitari, G.; Mancini, E; Grewe, V

    2003-01-01

    International audience A rigorous evaluation of five global Chemistry-Transport and two Chemistry-Climate Models operated by several different groups in Europe was performed by comparing the models with trace gas observations from a number of research aircraft measurement campaigns. Whenever possible the models were run over the four-year period 1995–1998 and at each simulation time step the instantaneous tracer fields were interpolated to all coinciding observation points. This approach a...

  5. 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. PMID:26705153

  6. D-558-2 being mounted to P2B-1S launch aircraft in hangar

    Science.gov (United States)

    1954-01-01

    This 1954 photograph shows a Douglas D-558-2 under the P2B-1S (Navy designation for a B-29) launch aircraft. The P2B-1S has been lifted on mechanical jacks in the hangar for a possible 'fit check' or the attachment of the Skyrocket for a flight. The P2B-1S had the nickname 'Fertile Myrtle.' On the side of its fuselage is a series of images indicating 41 launches by the mothership of D-558-2 #2 (NACA 144) and 44 by D-558-2 #3 (NACA 145). The Douglas D-558-2 'Skyrockets' were among the early transonic research airplanes like the X-1, X-4, X-5, and XF-92A. Three of the single-seat, swept-wing aircraft flew from 1948 to 1956 in a joint program involving the National Advisory Committee for Aeronautics (NACA), with its flight research done at the NACA's Muroc Flight Test Unit in Calif., redesignated in 1949 the High-Speed Flight Research Station (HSFRS); the Navy-Marine Corps; and the Douglas Aircraft Co. The HSFRS became the High-Speed Flight Station in 1954 and is now known as the NASA Dryden Flight Research Center. The Skyrocket made aviation history when it became the first airplane to fly twice the speed of sound. The 2 in the aircraft's designation referred to the fact that the Skyrocket was the phase-two version of what had originally been conceived as a three-phase program, with the phase-one aircraft having straight wings. The third phase, which never came to fruition, would have involved constructing a mock-up of a combat-type aircraft embodying the results from the testing of the phase one and two aircraft. Douglas pilot John F. Martin made the first flight at Muroc Army Airfield (later renamed Edwards Air Force Base) in Calif. on February 4, 1948. The goals of the program were to investigate the characteristics of swept-wing aircraft at transonic and supersonic speeds with particular attention to pitch-up (uncommanded rotation of the nose of the airplane upwards)--a problem prevalent in high-speed service aircraft of that era, particularly at low speeds

  7. Experimental Study on the Dynamic Performance of a New High-Speed Spindle Supported by Water-Lubricated Hybrid Bearings

    OpenAIRE

    Lin Wang; Hua Xu

    2016-01-01

    The dynamic performance of a new high-speed spindle supported by water-lubricated hybrid bearings is experimentally studied on a test rig. The present design allows the speed of the spindle up to 30,000 rpm, with a bearing internal diameter of 40 mm, which makes it possible to simulate many actual machining processes. Some experiments have been presented to study the mechanical and thermal behaviors of the spindle and its supporting hybrid bearings. The maximum temperature rise is less than 1...

  8. Trapping of slow-speed particles in a gas cell by the nonhomogeneous electromagnetic field intensifying with time

    CERN Document Server

    Izmailov, Azad Ch

    2014-01-01

    Author suggests and analyzes new universal trapping method of comparatively slow-speed particles of a rarefied gas medium in the potential well induced by the nonhomogeneous electromagnetic field increasing with time (up to some moment). Given method is especially effective at inelastic collisions of particles with walls of the gas cell when necessary preliminary slowdown of particles is possible for their following capture even to a highly shallow potential depth. Corresponding sufficiently compact and simple electromagnetic traps may be used for capture and accumulation not only slow-speed micro- and nano-particles in the high vacuum but also atoms and molecules of a rarefied gas in a cell.

  9. 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

    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...

  10. 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…

  11. Air speeds of migrating birds observed by ornithodolite and compared with predictions from flight theory.

    Science.gov (United States)

    Pennycuick, C J; Åkesson, Susanne; Hedenström, Anders

    2013-09-01

    We measured the air speeds of 31 bird species, for which we had body mass and wing measurements, migrating along the east coast of Sweden in autumn, using a Vectronix Vector 21 ornithodolite and a Gill WindSonic anemometer. We expected each species' average air speed to exceed its calculated minimum-power speed (Vmp), and to fall below its maximum-range speed (Vmr), but found some exceptions to both limits. To resolve these discrepancies, we first reduced the assumed induced power factor for all species from 1.2 to 0.9, attributing this to splayed and up-turned primary feathers, and then assigned body drag coefficients for different species down to 0.060 for small waders, and up to 0.12 for the mute swan, in the Reynolds number range 25 000-250 000. These results will be used to amend the default values in existing software that estimates fuel consumption in migration, energy heights on arrival and other aspects of flight performance, using classical aeronautical theory. The body drag coefficients are central to range calculations. Although they cannot be measured on dead bird bodies, they could be checked against wind tunnel measurements on living birds, using existing methods. PMID:23804440

  12. A new hybrid model optimized by an intelligent optimization algorithm for wind speed forecasting

    International Nuclear Information System (INIS)

    Highlights: • A new hybrid model is developed for wind speed forecasting. • The model is based on the Kalman filter and the ARIMA. • An intelligent optimization method is employed in the hybrid model. • The new hybrid model has good performance in western China. - Abstract: Forecasting the wind speed is indispensable in wind-related engineering studies and is important in the management of wind farms. As a technique essential for the future of clean energy systems, reducing the forecasting errors related to wind speed has always been an important research subject. In this paper, an optimized hybrid method based on the Autoregressive Integrated Moving Average (ARIMA) and Kalman filter is proposed to forecast the daily mean wind speed in western China. This approach employs Particle Swarm Optimization (PSO) as an intelligent optimization algorithm to optimize the parameters of the ARIMA model, which develops a hybrid model that is best adapted to the data set, increasing the fitting accuracy and avoiding over-fitting. The proposed method is subsequently examined on the wind farms of western China, where the proposed hybrid model is shown to perform effectively and steadily

  13. 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 conver...

  14. Minimum Wave Speed Solution of Fisher's Equation by the Method of Least Squares - A Note

    OpenAIRE

    K. N. Mehta

    1989-01-01

    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. 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

  16. 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...

  17. High-speed spectral calibration by complex FIR filter in phase-sensitive optical coherence tomography.

    Science.gov (United States)

    Kim, Sangmin; Raphael, Patrick D; Oghalai, John S; Applegate, Brian E

    2016-04-01

    Swept-laser sources offer a number of advantages for Phase-sensitive Optical Coherence Tomography (PhOCT). However, inter- and intra-sweep variability leads to calibration errors that adversely affect phase sensitivity. While there are several approaches to overcoming this problem, our preferred method is to simply calibrate every sweep of the laser. This approach offers high accuracy and phase stability at the expense of a substantial processing burden. In this approach, the Hilbert phase of the interferogram from a reference interferometer provides the instantaneous wavenumber of the laser, but is computationally expensive. Fortunately, the Hilbert transform may be approximated by a Finite Impulse-Response (FIR) filter. Here we explore the use of several FIR filter based Hilbert transforms for calibration, explicitly considering the impact of filter choice on phase sensitivity and OCT image quality. Our results indicate that the complex FIR filter approach is the most robust and accurate among those considered. It provides similar image quality and slightly better phase sensitivity than the traditional FFT-IFFT based Hilbert transform while consuming fewer resources in an FPGA implementation. We also explored utilizing the Hilbert magnitude of the reference interferogram to calculate an ideal window function for spectral amplitude calibration. The ideal window function is designed to carefully control sidelobes on the axial point spread function. We found that after a simple chromatic correction, calculating the window function using the complex FIR filter and the reference interferometer gave similar results to window functions calculated using a mirror sample and the FFT-IFFT Hilbert transform. Hence, the complex FIR filter can enable accurate and high-speed calibration of the magnitude and phase of spectral interferograms. PMID:27446666

  18. Comparison between AC and MFDC resistance spot welding by using high speed filming

    Directory of Open Access Journals (Sweden)

    S.C.A. Alfaro

    2007-09-01

    Full Text Available Purpose: In this work it will be carried through the filming of the formation and growth of the nugget in resistance spot welding executed in AC and MF. A comparison for same times in both the processes will be carried through to verify which of the used processes offers better conditions, control and results as well as will help for one better understanding of the process aiming at the otimização.Design/methodology/approach: Two different spot welding machine (AC and MF-DC had been used, and a digital high-speed camera. The weld points had been carried through in 3 galvanized steel different plate configurations. The electrodes had been truncated to obtain one better visualization for the weld nugget formation. The comparison of the formation and development between the weld point of each process (AC and MF is shown in 7 pictures in the same values of time.Findings: For currents below 2 kA, no nugget was observed. and the formation of same after 10º cycle for bigger current of 3 kA. The MF-DC welding offers the possibility of obtaining nuggets more uniforms within shorter times (depending on the plate configuration.Research limitations/implications: In this work the AC machine is limited by the values of current of welding and pressure of the electrodes: (2 - 6 kA e (87 - 261 kgf respectively. Other materials: aluminum, stainless steel or material exactly dissimilar could be used following the line of this research. Bigger currents levels can also be used.Originality/value: The idea to compare resulted for the same process of welding under different conditions (equipment, materials and or parameters makes possible the choice of these better conditions used to the otimização of the process.

  19. Use of multisensor fusion technology to meet the challenges of emerging EO and RF threats to a combat aircraft

    Science.gov (United States)

    Shukla, Arvind K.; Parthasarathy, T.; Rao, P. N. A. P.

    2003-04-01

    The pilot on-board a combat aircraft encounters during any mission a dynamically varying threat environment of diverse EO and RF threats. Different sensors are carried on-board the aircraft to combat these threats. However, these sensors have their own limitations and no single sensor is able to perform in all kinds of situations. In addition, the technological advances in the threat scenario - in terms of higher speeds, small signatures and multimode guidance - and increased complex threats in the battlefield leading to generation of large amount of data input to the pilot make his decision making task very difficult due to increased workload. These challenges can be efficiently handled by deployment of a system on-board the aircraft with a comprehensive goal of autonomous target detection and tracking, situation and threat assessment and decision making based on multi-sensor data fusion techniques. In this paper, major emerging EO and RF threats for a combat aircraft and some important EO and RF sensors on-board the aircraft have been discussed. A design approach for the development of a multi-sensor data fusion system for a combat aircraft to provide better threat assessment than that provided by any single stand alone sensor has also been presented.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Experimental analysis of buckling in aircraft skin panels by fibre optic sensors

    Science.gov (United States)

    Güemes, J. A.; Menendez, J. M.; Frövel, M.; Fernandez, I.; Pintado, J. M.

    2001-06-01

    Three blade-stiffened CFRP panels with co-cured stiffener webs, manufactured by means of an elastomeric mould, have been tested under compressive load. Several Bragg grating sensors have been surface bonded on two of the stiffened panels and have been embedded into the stiffener webs of the third panel. The Bragg grating sensors measured the strain distribution in the stiffener web and in the skin panels. The bucking onset was clearly detected in every case, the post-buckling behaviour can be tracked, but the information is heavily dependent on the right choice of the sensor position and the buckling mode. To calibrate the system, and to evaluate the influence of different curing pressures, and the use of unidirectional or fabric prepreg material, tensile test specimens were made on flat panels. The strain measurements provided by the optical fibre sensors in tensile tests were compared with the strain measurements provided by conventional clamp extensometers.

  5. Evaluation of Streamwise Waveform on a High-Speed Water Jet by Detecting Trajectories of Two Refracted Laser Beams

    Directory of Open Access Journals (Sweden)

    Kazuhiro Itoh

    2011-01-01

    Full Text Available Free surface fluctuations on a high-speed water jet were measured by a laser beam refraction technique. This method can be used to obtain quantitative time-series data on local surface fluctuations. The developed system employs two pulsed laser diodes, and it uses a high-speed optical sensor to detect the instantaneous positions of the laser beams that are refracted at the free surface. Fluctuations in the slope angle are measured at two locations separated by 1.27 mm. The wave speed of each free surface wave, which is determined by the zero-upcrossing method, is experimentally evaluated by the cross-correlation method. A two-dimensional waveform is obtained by integrating the slope angle data. The local mean wavelength and mean wave steepness are evaluated for average jet velocities up to =10 m/s. Streamwise waveforms of the high-speed water jet at several locations exhibit appreciable asymmetry and have steep profiles.

  6. 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.

  7. Prediction of flow separation from aircraft tails using a RSM turbulence model

    Science.gov (United States)

    Masi, Andrea; Benton, Jeremy; Tucker, Paul G.

    2014-11-01

    Enhancing engineers' capability to predict flow separation would generate important benefits in aircraft design. In this study the attention is focused on the vertical tail plane (VTP), which consists of a fixed part (the fin) and a moveable control surface (the rudder). For standard two-engine aircraft configurations, the size of the VTP is driven by the condition of loss of an engine during takeoff and low speed climb: in this condition the fin and the rudder have to be sufficient in size to balance the aircraft. Due to uncertainties in prediction of VTP effectiveness, aircraft designers keep to a conservative approach, risking specifying a larger size for the VTP than it is probably necessary. Uncertainties come from difficulties in predicting the separation of the flow from the surfaces of the aircraft using current CFD techniques, which are based on the use of RANS equations with eddy viscosity turbulence models. The CFD simulations presented in this study investigate the use of a RSM turbulence model with RANS and URANS. The introduction of a time-dependency gives benefits in the accuracy of the flow solution in presence of massive flow separation. This leads to the investigation of hybrid RANS/LES techniques with the aim of improving the solution of the detached flow. EU FP7 project ANADE (Grant Agreement Number 289428).

  8. 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

  9. 75 FR 82329 - Airworthiness Directives; Piper Aircraft, Inc. (Type Certificate Previously Held by The New Piper...

    Science.gov (United States)

    2010-12-30

    ... new service information. We are proposing this AD to prevent improper engine operation caused by... FULL RICH mixture to assure adequate fuel flow for engine cooling. (2) If the turbine inlet temperature... revised related service information and added an airplane model to the list of affected airplanes....

  10. 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.

  11. An evaluation of the performance of chemistry transport models by comparison with research aircraft observations. Part 1: Concepts and overall model performance

    OpenAIRE

    Brunner, D.; Staehelin, J; Rogers, H. L.; Köhler, M. O.; Pyle, J.A.; Hauglustaine, D.; Jourdain, L.; Berntsen, T. K.; Gauss, M.; I. S. A. Isaksen; MEIJER E.; Van Velthoven, P.; Pitari, G.; Mancini, E; Grewe, G.

    2003-01-01

    A rigorous evaluation of five global Chemistry-Transport and two Chemistry-Climate Models operated by several different groups in Europe, was performed. Comparisons were made of the models with trace gas observations from a number of research aircraft measurement campaigns during the four-year period 1995-1998. Whenever possible the models were run over the same four-year period and at each simulation time step the instantaneous tracer fields were interpolated to all coinciding observati...

  12. An evaluation of the performance of chemistry transport models by comparison with research aircraft observations. Part 1: Concepts and overall model performance

    OpenAIRE

    Brunner, D.; Staehelin, J; Rogers, H. L.; Köhler, M. O.; Pyle, J.A.; Hauglustaine, D.; Jourdain, L.; Berntsen, T. K.; Gauss, M.; I. S. A. Isaksen; MEIJER E.; Van Velthoven, P.; Pitari, G.; Mancini, E; Grewe, G.

    2003-01-01

    International audience A rigorous evaluation of five global Chemistry-Transport and two Chemistry-Climate Models operated by several different groups in Europe, was performed. Comparisons were made of the models with trace gas observations from a number of research aircraft measurement campaigns during the four-year period 1995-1998. Whenever possible the models were run over the same four-year period and at each simulation time step the instantaneous tracer fields were interpolated to all...

  13. An evaluation of the performance of chemistry transport models by comparison with research aircraft observations. Part 1: Concepts and overall model performance

    OpenAIRE

    Brunner, D.; Staehelin, J; Rogers, H. L.; Köhler, M. O.; Pyle, J.A.; Hauglustaine, D.; Jourdain, L.; Berntsen, T. K.; Gauss, M.; I. S. A. Isaksen; MEIJER E.; Van Velthoven, P.; Pitari, G.; Mancini, E; Grewe, G.

    2003-01-01

    A rigorous evaluation of five global Chemistry-Transport and two Chemistry-Climate Models operated by several different groups in Europe, was performed. Comparisons were made of the models with trace gas observations from a number of research aircraft measurement campaigns during the four-year period 1995-1998. Whenever possible the models were run over the same four-year period and at each simulation time step the instantaneous tracer fields were interpol...

  14. 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.

  15. The Attenuation of a Detonation Wave by an Aircraft Engine Axial Turbine Stage

    Science.gov (United States)

    VanZante, Dale; Envia, Edmane; Turner, Mark G.

    2007-01-01

    A Constant Volume Combustion Cycle Engine concept consisting of a Pulse Detonation Combustor (PDC) followed by a conventional axial turbine was simulated numerically to determine the attenuation and reflection of a notional PDC pulse by the turbine. The multi-stage, time-accurate, turbomachinery solver TURBO was used to perform the calculation. The solution domain consisted of one notional detonation tube coupled to 5 vane passages and 8 rotor passages representing 1/8th of the annulus. The detonation tube was implemented as an initial value problem with the thermodynamic state of the tube contents, when the detonation wave is about to exit, provided by a 1D code. Pressure time history data from the numerical simulation was compared to experimental data from a similar configuration to verify that the simulation is giving reasonable results. Analysis of the pressure data showed a spectrally averaged attenuation of about 15 dB across the turbine stage. An evaluation of turbine performance is also presented.

  16. 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.

  17. A new control strategy with saturation effect compensation for an autonomous induction generator driven by wide speed range turbines

    International Nuclear Information System (INIS)

    Research highlights: → A novel control strategy for autonomous induction generators with variable rotor speed. → Generator excitation achieved using a current controlled voltage source inverter. → Machine optimized use with stability and saturation effect compensation. → Both saturation and cross-saturation effects discussed upon generator modeling. → 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.

  18. 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.

  19. Experimental study of high-speed counter-rotation propeller on low speed wind range; Dojiku hantengata kosoku propeller no teisokuiki ni okeru fudo jikken

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Collaborative research was conducted by National Aerospace Laboratory and Japan Aircraft Development Company in the period of fiscal 1988-1992 into methods for testing aircraft with advanced propeller in low-speed wind tunnel. The propulsion efficiency of the currently available high-bypass turbofan engine is approximately 60% in the vicinity of Mach number 0.85. Propeller-driven aircraft, whose propulsion efficiency is as high as 80% in the low Mach number domain, are scarcely in practical use in the domain of Mach number 0.75 or higher. There are studies reported abroad as well as in Japan for the propeller-driven aircraft to enjoy higher propeller propulsion efficiency even in the vicinity of Mach number 0.8 by modifying the propeller diameter, number of blades, and blade sections, etc. This paper describes the experimental research into the high-speed counter-rotation propeller. A counter-rotation propeller 0.3m in diameter and provided with coaxially arranged 8times2 SR-2 blades is evaluated for pitch angles during the takeoff and landing modes, for thrust characteristics at the pitch angle for the cruising mode, and for propeller backwash and noise. 15 refs., 72 figs., 9 tabs.

  20. Light shaping diffusers{trademark} improve aircraft inspection

    Energy Technology Data Exchange (ETDEWEB)

    Shagam, R.N. [Sandia National Labs., Albuquerque, NM (United States); Shie, R.; Lerner, J. [Physical Optics Corp., Torrance, CA (United States)

    1994-11-01

    Physical Optical Corporation has introduced a Light Shaping Diffuser{trademark} (LSD) for the specialized illumination requirements of aircraft inspection. Attached to a handheld, battery-powered flashlight, this light-weight, holographic diffuser element provides bright, even illumination as aircraft inspectors perform the important task of visually examining aircraft for possible structural defects. Field trials conducted by the Aging Aircraft Program at Sandia National Laboratories confirm that the LSD-equipped flashlights are preferred by visual inspectors over stock flashlights.

  1. Corrosion of aluminum alloy 2024 by microorganisms isolated from aircraft fuel tanks.

    Science.gov (United States)

    McNamara, Christopher J; Perry, Thomas D; Leard, Ryan; Bearce, Ktisten; Dante, James; Mitchell, Ralph

    2005-01-01

    Microorganisms frequently contaminate jet fuel and cause corrosion of fuel tank metals. In the past, jet fuel contaminants included a diverse group of bacteria and fungi. The most common contaminant was the fungus Hormoconis resinae. However, the jet fuel community has been altered by changes in the composition of the fuel and is now dominated by bacterial contaminants. The purpose of this research was to determine the composition of the microbial community found in fuel tanks containing jet propellant-8 (JP-8) and to determine the potential of this community to cause corrosion of aluminum alloy 2024 (AA2024). Isolates cultured from fuel tanks containing JP-8 were closely related to the genus Bacillus and the fungi Aureobasidium and Penicillium. Biocidal activity of the fuel system icing inhibitor diethylene glycol monomethyl ether is the most likely cause of the prevalence of endospore forming bacteria. Electrochemical impedance spectroscopy and metallographic analysis of AA2024 exposed to the fuel tank environment indicated that the isolates caused corrosion of AA2024. Despite the limited taxonomic diversity of microorganisms recovered from jet fuel, the community has the potential to corrode fuel tanks. PMID:16522539

  2. 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.

  3. Literature study of climate effects of contrails caused by aircraft emissions

    Energy Technology Data Exchange (ETDEWEB)

    Pultau, V.E.

    1998-07-01

    By order of EUROCONTROL, a study of the most recent literature concerning contrails was performed. Attention was paid to the latest research findings concerning the formation, the lifetime, the frequency, the microphysical properties and the radiative forcing of contrails and their climate effects. Contrails form when saturation with respect to water is temporarily reached in the plume and they persist in ice supersaturated air masses. The ambient temperature necessary for contrail formation can be predicted accurately. Contrail particles consist of ice crystals. Young persistent contrails are composed of more, but smaller ice crystals than typical cirrus. Persistent contrails develop towards cirrus clouds in the course of time. The average contrail coverage exhibits a value of around 0.5% over Europe. The mean global contrail cover is estimated to be of order of 0.1%. The net radiation effect of contrails is believed to enhance warming of the troposphere on average. 59 refs.

  4. The structure of the unstable marine boundary layer viewed by lidar and aircraft observations

    Science.gov (United States)

    Atlas, D.; Walter, B.; Chou, S.-H.; Sheu, P. J.

    1986-01-01

    The marine atmospheric boundary layer (MABL) during a cold-air outbreak off the Atlantic coast between New York and Virginia on January 20, 1983 is characterized on the basis of airborne lidar observations, vertical soundings (potential temperature, vapor mixing ratio, relative humidity, and wind), and horizontal (770-m) temperature records. The data are presented in tables and graphs and analyzed in detail. The organization of the MABL is defined by 1-2-km-scale roll vortices with up and downdrafts of 2-4 m/s at 210 m; north-south orientation of the roll axes (parallel to the low-level winds); rising arms coinciding with updrafts rich in moisture, aerosols, and heat; and 150-200-m (peak-to-trough) undulations of the inversion. Consideration is given to problems inherent in the interpretation of lidar data for MABL studies.

  5. Aircraft landing using GPS

    Science.gov (United States)

    Lawrence, David Gary

    The advent of the Global Positioning System (GPS) is revolutionizing the field of navigation. Commercial aviation has been particularly influenced by this worldwide navigation system. From ground vehicle guidance to aircraft landing applications, GPS has the potential to impact many areas of aviation. GPS is already being used for non-precision approach guidance; current research focuses on its application to more critical regimes of flight. To this end, the following contributions were made: (1) Development of algorithms and a flexible software architecture capable of providing real-time position solutions accurate to the centimeter level with high integrity. This architecture was used to demonstrate 110 automatic landings of a Boeing 737. (2) Assessment of the navigation performance provided by two GPS-based landing systems developed at Stanford, the Integrity Beacon Landing System, and the Wide Area Augmentation System. (3) Preliminary evaluation of proposed enhancements to traditional techniques for GPS positioning, specifically, dual antenna positioning and pseudolite augmentation. (4) Introduction of a new concept for positioning using airport pseudolites. The results of this research are promising, showing that GPS-based systems can potentially meet even the stringent requirements of a Category III (zero visibility) landing system. Although technical and logistical hurdles still exist, it is likely that GPS will soon provide aircraft guidance in all phases of flight, including automatic landing, roll-out, and taxi.

  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. Introduction to unmanned aircraft systems

    CERN Document Server

    Marshall, Douglas M; Hottman, Stephen B; Shappee, Eric; Most, Michael Thomas

    2011-01-01

    Introduction to Unmanned Aircraft Systems is the editors' response to their unsuccessful search for suitable university-level textbooks on this subject. A collection of contributions from top experts, this book applies the depth of their expertise to identify and survey the fundamentals of unmanned aircraft system (UAS) operations. Written from a nonengineering civilian operational perspective, the book starts by detailing the history of UASs and then explores current technology and what is expected for the future. Covering all facets of UAS elements and operation-including an examination of s

  8. Designing A Conventional Aircraft

    OpenAIRE

    Sonei, Arash

    2014-01-01

    This paper is explaining the important design phases of dimensioning an unmanned conventional aircraft from scratch and will also design one according to a few chosen requirements. The design phases discussed will be all from wing dimensioning to stability and spin recovery, aircraft performance requirements and how to select a motor which overcomes these. As well as the optimal rate of climb for improved efficiency is discussed. In the end an aircraft which manages the set requirements and i...

  9. Speed Detection and Diagnosis of Symptoms by Using Color and Shape Information

    Directory of Open Access Journals (Sweden)

    Hamed Hamidi Rad

    2011-10-01

    Full Text Available Color and shape are basic characteristics which are used to recognize traffic signs. In this paper, a new speed limit sign detection method in various conditions is proposed. In this method, color image is segmented based on a thresholding technique in HSI color space. Then, corner features are detected using convolution masks and found the location of sign. The first advantage of this method is high accuracy to detect the location of sign. So, the object can be detected with 30% noise level, 30 meters for distances of signs, and for rotated signs. The second advantage of the proposed method is high speed in sign detection. Utimately, the type of sign can be recognized with eliminate redundant information and match between extracted image and database image. If the illumination conditions be ideal, the recognition rate is obtained to 89%.

  10. 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. PMID:26631246

  11. A high ozone episode in winter 2013 in the Uinta Basin oil and gas region characterized by aircraft measurements

    Science.gov (United States)

    Oltmans, S. J.; Karion, A.; Schnell, R. C.; Pétron, G.; Sweeney, C.; Wolter, S.; Neff, D.; Montzka, S. A.; Miller, B. R.; Helmig, D.; Johnson, B. J.; Hueber, J.

    2014-08-01

    During the winter of 2012-2013 atmospheric surface ozone mole fractions exceeded the US 8 h standard of 75 ppb on 39 days in the Uinta Basin of Utah. As part of the Uinta Basin Winter Ozone Study (UBWOS) aircraft flights were conducted throughout the basin with continuous measurements of ozone (O3), methane (CH4), carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2), and discrete whole air flask samples for determination of ∼50 trace gases including a number of non-methane hydrocarbons (NMHCs). During the course of seven flights conducted between 31 January and 7 February 2013, coinciding with strong, multi-day temperature inversions, O3 levels gradually built up in the shallow boundary layer from ∼45 ppb to ∼140 ppb. Near-surface CH4 mole fractions increased during the episode from near background levels of ∼2 ppm to over 10 ppm. Based on elevated levels of CH4 across the basin and high correlations of CH4 with NMHCs from the discrete air samples, O3 precursor NMHCs were also inferred to be elevated throughout the basin. Discrete plumes of high NO2 were observed in the gas production region of the basin suggesting that gas processing plants and compressor facilities were important point sources of reactive nitrogen oxides (NOx). Vertical profiles obtained during the flights showed that the high O3 mole fractions (as well as other elevated constituents) were confined to a shallow layer from near the ground to 300-400 m above ground level (m a.g.l.) capped by a strong temperature inversion. The highest mole fractions of the measured constituents during the study period were in an isothermal cold layer that varied from ∼300 m depth on 4 February to ∼150 m on 5 February. A gradient layer with declining mole fractions with altitude extended above the isothermal layer to ∼1900 m a.s.l. (300-400 m a.g.l.) indicative of some mixing of air out of the boundary layer. O3 mole fractions continued to increase within the basin as the high O3 episode

  12. A high ozone episode in winter 2013 in the Uinta Basin oil and gas region characterized by aircraft measurements

    Directory of Open Access Journals (Sweden)

    S. J. Oltmans

    2014-08-01

    Full Text Available During the winter of 2012–2013 atmospheric surface ozone mole fractions exceeded the US 8 h standard of 75 ppb on 39 days in the Uinta Basin of Utah. As part of the Uinta Basin Winter Ozone Study (UBWOS aircraft flights were conducted throughout the basin with continuous measurements of ozone (O3, methane (CH4, carbon dioxide (CO2, carbon monoxide (CO, nitrogen dioxide (NO2, and discrete whole air flask samples for determination of ∼50 trace gases including a number of non-methane hydrocarbons (NMHCs. During the course of seven flights conducted between 31 January and 7 February 2013, coinciding with strong, multi-day temperature inversions, O3 levels gradually built up in the shallow boundary layer from ∼45 ppb to ∼140 ppb. Near-surface CH4 mole fractions increased during the episode from near background levels of ∼2 ppm to over 10 ppm. Based on elevated levels of CH4 across the basin and high correlations of CH4 with NMHCs from the discrete air samples, O3 precursor NMHCs were also inferred to be elevated throughout the basin. Discrete plumes of high NO2 were observed in the gas production region of the basin suggesting that gas processing plants and compressor facilities were important point sources of reactive nitrogen oxides (NOx. Vertical profiles obtained during the flights showed that the high O3 mole fractions (as well as other elevated constituents were confined to a shallow layer from near the ground to 300–400 m above ground level (m a.g.l. capped by a strong temperature inversion. The highest mole fractions of the measured constituents during the study period were in an isothermal cold layer that varied from ∼300 m depth on 4 February to ∼150 m on 5 February. A gradient layer with declining mole fractions with altitude extended above the isothermal layer to ∼1900 m a.s.l. (300–400 m a.g.l. indicative of some mixing of air out of the boundary layer. O3 mole fractions continued to increase within the basin as the

  13. Age Differences in Speed of Processing are Partially Mediated by Differences in Axonal Integrity

    OpenAIRE

    Burgmans, S.; Gronenschild, E. H. B. M.; Fandakova, Y.; Shing, Y.L.; van Boxtel, M.P.J.; Vuurman, E.F.P.M.; Uylings, H.B.M.; Jolles, J; Raz, N.

    2011-01-01

    Advanced age is associated with declines in brain structure and in cognitive performance, but it is unclear, which aspects of brain aging mediate cognitive declines. We inquired if individual differences in white matter integrity contribute to age differences in two cognitive domains with established vulnerability to aging: executive functioning and speed of processing. The participants were healthy volunteers age 50–81, some of whom had elevated blood pressure, a known vascular risk factor. ...

  14. High-speed Vibrational Imaging and Spectral Analysis of Lipid Bodies by Compound Raman Microscopy

    OpenAIRE

    Slipchenko, Mikhail N.; Le, Thuc T.; Chen, Hongtao; Cheng, Ji-Xin

    2009-01-01

    Cells store excess energy in the form of cytoplasmic lipid droplets. At present, it is unclear how different types of fatty acids contribute to the formation of lipid-droplets. We describe a compound Raman microscope capable of both high-speed chemical imaging and quantitative spectral analysis on the same platform. We use a picosecond laser source to perform coherent Raman scattering imaging of a biological sample and confocal Raman spectral analysis at points of interest. The potential of t...

  15. High-speed label-free detection by spinning-disk micro-interferometry

    OpenAIRE

    Varma, M. M.; Inerowicz, H. D.; Regnier, F. E.; Nolte, D. D.

    2004-01-01

    Spinning-disk interferometers are a new class of analytic sensors to detect immobilized biomolecules with high speed and high sensitivity. The disks are composed of a large number of surface-normal self-referencing interferometers, analogous to an optical CD, but operating on the principle of microdiffraction quadrature that achieves sensitive linear detection of bound molecules. The surface-normal structures have a small footprint of only 20 mum each, allowing potential integration to over a...

  16. MODELING AND ANALYSIS OF DISTRIBUTION LOAD CURRENTS PRODUCED BY AN AD JUSTABLE SPEED DRIVE HEAT PUMP

    OpenAIRE

    Hoffman, Stephen Paul

    1993-01-01

    A number of demand side management techniques have been proposed for the efficient use of electric power in the commercial and residential sector. The adjustable speed drive heat pump is a technology which has the prospect of decreasing power demands for space heating. This design has the advantage over conventional designs of higher efficiency and, potentially, reduction of peak power demand. Its main disadvantage is higher cost. Further, it has the disadvantage that it produces a load curre...

  17. Flashback investigations in a premixed swirl burner by high-speed laser imaging

    OpenAIRE

    Heeger, Christof

    2012-01-01

    In this thesis flame flashback in a lean premixed swirl burner with central bluff-body was investigated using high speed multi-parameter laser imaging diagnostics. Starting with the fundamentals, the theoretical background of fluid dynamics was presented. This included turbulence, swirl and flows in boundary layers. Regarding the involved chemistry, the oxidation of methane was detailed and six mechanisms of nitric oxides formation together with reduction strategies were pictured. Lean premix...

  18. Human Response to Aircraft Noise

    NARCIS (Netherlands)

    Kroesen, M.

    2011-01-01

    How can it be that one person is extremely annoyed by the sounds of aircrafts, while his neighbour claims not to be bothered at all? The present thesis attempts to explain this observation by applying a range of quantitative methods to field data gathered among residents living near large airports.

  19. 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.

  20. 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

  1. 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.

  2. Impact of Advanced Propeller Technology on Aircraft/Mission Characteristics of Several General Aviation Aircraft

    Science.gov (United States)

    Keiter, I. D.

    1982-01-01

    Studies of several General Aviation aircraft indicated that the application of advanced technologies to General Aviation propellers can reduce fuel consumption in future aircraft by a significant amount. Propeller blade weight reductions achieved through the use of composites, propeller efficiency and noise improvements achieved through the use of advanced concepts and improved propeller analytical design methods result in aircraft with lower operating cost, acquisition cost and gross weight.

  3. Range imaging behind semi-transparent surfaces by high-speed modulated light

    Science.gov (United States)

    Geerardyn, D.; Ingelberts, H.; Deleener, R.; Kuijk, M.

    2015-05-01

    Range-imaging is a measurement technique able to generate an image which contains the distance information from the camera to all the points of a scene. This distance information can be captured by, amongst others, the Time-of-Flight principle which measures the time a light pulse needs to travel back and forth from the camera to the scene and converts this time into a depth value. For a good operation of the Time-of-Flight principle, a high-power, fast-modulated light source is required. Currently, most 3D cameras use laser diodes or LEDs. Moreover, most systems use square-wave modulation of the light source, requiring high bandwidths of the optical driver. To enhance both bandwidth and optical power, we developed a light source consisting of 16 high-power (50 mW) laser diodes using GHz laser drivers, combined with GHz buffers. Moreover, this light source can be integrated in a Time-of-Flight camera. Specifically, we designed and experimentally validated this new light source, based on ultra-fast laser diodes, allowing an increased performance of the current Time-of-Flight cameras. In this paper, we first discuss the development of a high-power illumination board, with a large beam divergence and suitable for high-speed square-wave modulation with a chosen duty-cycle. Our light source can be modulated faster than 1 GHz, which corresponds to optical pulses shorter than 500 ps. Moreover, the pulses can be shifted in time with sub-nanosecond precision. Secondly, we integrated this light source into a Time-of-Flight setup, able to measure the distances of objects behind a semi-transparent surface. The resulting images are compared with the image quality of commercially available Time-of-Flight cameras. From these results, we can conclude that our light source is suitable for Time-of-Flight measurements and gives a low-cost alternative for imaging purposes. Moreover, it can handle both pulsed as continuous-wave Time-of-Flight, to allow a broader range of applications.

  4. The contribution of aircraft emissions to the atmospheric sulfur budget

    Energy Technology Data Exchange (ETDEWEB)

    Kjellstroem, E. [Stockholm Univ. (Sweden). Dept. of Meteorology; Feichter, J. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Sausen, R.; Hein, R. [Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    1998-01-01

    An atmospheric general circulation model including the atmospheric sulfur cycle has been used to investigate the impact of aircraft sulfur emissions on the global sulfur budget of the atmosphere. The relative contribution from aircraft sulfur to the atmospheric sulfate burden is larger than the ratio between aircraft emissions and surface emissions due to the calculated long turn-over time of aircraft sulfate (about 12 days). However, in terms of the sulfate mass balance, aircraft emissions are small, contributing about 1% of the total sulfate mass north of 40 deg C where the aircraft emissions are largest. Despite this small contribution to sulfate mass, the aircraft emissions could potentially significantly enhance the background number concentration of aerosol particles. Based on the model calculations the increased stratospheric background aerosol mass observed during the last decades can not be explained by increased aircraft sulfur emissions 50 refs, 9 figs, 4 tabs

  5. Aircraft detection based on probability model of structural elements

    Science.gov (United States)

    Chen, Long; Jiang, Zhiguo

    2014-11-01

    Detecting aircrafts is important in the field of remote sensing. In past decades, researchers used various approaches to detect aircrafts based on classifiers for overall aircrafts. However, with the development of high-resolution images, the internal structures of aircrafts should also be taken into consideration now. To address this issue, a novel aircrafts detection method for satellite images based on probabilistic topic model is presented. We model aircrafts as the connected structural elements rather than features. The proposed method contains two major steps: 1) Use Cascade-Adaboost classier to identify the structural elements of aircraft firstly. 2) Connect these structural elements to aircrafts, where the relationships between elements are estimated by hierarchical topic model. The model places strict spatial constraints on structural elements which can identify differences between similar features. The experimental results demonstrate the effectiveness of the approach.

  6. Experimental Study on the Dynamic Performance of a New High-Speed Spindle Supported by Water-Lubricated Hybrid Bearings

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2016-01-01

    Full Text Available The dynamic performance of a new high-speed spindle supported by water-lubricated hybrid bearings is experimentally studied on a test rig. The present design allows the speed of the spindle up to 30,000 rpm, with a bearing internal diameter of 40 mm, which makes it possible to simulate many actual machining processes. Some experiments have been presented to study the mechanical and thermal behaviors of the spindle and its supporting hybrid bearings. The maximum temperature rise is less than 15°C with a speed of 30,000 rpm and a water supply pressure of 2.5 MPa. The spindle radial run-out of the rotational frequency is about 1 µm. Stability of the spindle system has been improved. The experimental results indicate that water-lubricated hybrid bearings are valuable choices to replace ceramic bearings and air bearings as support for spindles under high-speed, high-precision, and heavy-load machining conditions.

  7. Automatic detection of aircraft emergency landing sites

    Science.gov (United States)

    Shen, Yu-Fei; Rahman, Zia-ur; Krusienski, Dean; Li, Jiang

    2011-06-01

    An automatic landing site detection algorithm is proposed for aircraft emergency landing. Emergency landing is an unplanned event in response to emergency situations. If, as is unfortunately usually the case, there is no airstrip or airfield that can be reached by the un-powered aircraft, a crash landing or ditching has to be carried out. Identifying a safe landing site is critical to the survival of passengers and crew. Conventionally, the pilot chooses the landing site visually by looking at the terrain through the cockpit. The success of this vital decision greatly depends on the external environmental factors that can impair human vision, and on the pilot's flight experience that can vary significantly among pilots. Therefore, we propose a robust, reliable and efficient algorithm that is expected to alleviate the negative impact of these factors. We present only the detection mechanism of the proposed algorithm and assume that the image enhancement for increased visibility, and image stitching for a larger field-of-view have already been performed on the images acquired by aircraftmounted cameras. Specifically, we describe an elastic bound detection method which is designed to position the horizon. The terrain image is divided into non-overlapping blocks which are then clustered according to a "roughness" measure. Adjacent smooth blocks are merged to form potential landing sites whose dimensions are measured with principal component analysis and geometric transformations. If the dimensions of the candidate region exceed the minimum requirement for safe landing, the potential landing site is considered a safe candidate and highlighted on the human machine interface. At the end, the pilot makes the final decision by confirming one of the candidates, also considering other factors such as wind speed and wind direction, etc. Preliminary results show the feasibility of the proposed algorithm.

  8. The Effect of Rotor Cruise Tip Speed, Engine Technology and Engine/Drive System RPM on the NASA Large Civil Tiltrotor (LCTR2) Size and Performance

    Science.gov (United States)

    Robuck, Mark; Wilkerson, Joseph; Maciolek, Robert; Vonderwell, Dan

    2012-01-01

    A multi-year study was conducted under NASA NNA06BC41C Task Order 10 and NASA NNA09DA56C task orders 2, 4, and 5 to identify the most promising propulsion system concepts that enable rotor cruise tip speeds down to 54% of the hover tip speed for a civil tiltrotor aircraft. Combinations of engine RPM reduction and 2-speed drive systems were evaluated. Three levels of engine and the drive system advanced technology were assessed; 2015, 2025 and 2035. Propulsion and drive system configurations that resulted in minimum vehicle gross weight were identified. Design variables included engine speed reduction, drive system speed reduction, technology, and rotor cruise propulsion efficiency. The NASA Large Civil Tiltrotor, LCTR, aircraft served as the base vehicle concept for this study and was resized for over thirty combinations of operating cruise RPM and technology level, quantifying LCTR2 Gross Weight, size, and mission fuel. Additional studies show design sensitivity to other mission ranges and design airspeeds, with corresponding relative estimated operational cost. The lightest vehicle gross weight solution consistently came from rotor cruise tip speeds between 422 fps and 500 fps. Nearly equivalent results were achieved with operating at reduced engine RPM with a single-speed drive system or with a two-speed drive system and 100% engine RPM. Projected performance for a 2025 engine technology provided improved fuel flow over a wide range of operating speeds relative to the 2015 technology, but increased engine weight nullified the improved fuel flow resulting in increased aircraft gross weights. The 2035 engine technology provided further fuel flow reduction and 25% lower engine weight, and the 2035 drive system technology provided a 12% reduction in drive system weight. In combination, the 2035 technologies reduced aircraft takeoff gross weight by 14% relative to the 2015 technologies.

  9. NASA/RAE collaboration on nonlinear control using the F-8C digital fly-by-wire aircraft

    Science.gov (United States)

    Butler, G. F.; Corbin, M. J.; Mepham, S.; Stewart, J. F.; Larson, R. R.

    1983-01-01

    Design procedures are reviewed for variable integral control to optimize response (VICTOR) algorithms and results of preliminary flight tests are presented. The F-8C aircraft is operated in the remotely augmented vehicle (RAV) mode, with the control laws implemented as FORTRAN programs on a ground-based computer. Pilot commands and sensor information are telemetered to the ground, where the data are processed to form surface commands which are then telemetered back to the aircraft. The RAV mode represents a singlestring (simplex) system and is therefore vulnerable to a hardover since comparison monitoring is not possible. Hence, extensive error checking is conducted on both the ground and airborne computers to prevent the development of potentially hazardous situations. Experience with the RAV monitoring and validation procedures is described.

  10. Aircraft Stand Allocation with Associated Resource Scheduling

    DEFF Research Database (Denmark)

    Justesen, Tor Fog; Larsen, Jesper; Lusby, Richard Martin;

    An aircraft turn-round refers to the set of processes taking place from when an aircraft parks at its arrival stand until the time it departs from its departure stand. When handling a turn-round, the different processes involved (arrival, disembarkation of passengers, cleaning, etc.) require...... different ground handling resources (taxiways, aircraft stands, gates, etc) at different times. Each resource can be claimed by at most one turn-round at a time. The aircraft stand allocation problem with associated resource scheduling is the problem of allocating the required ground handling resources...... to handle a given set of aircraft turn-rounds. We develop a set packing-based model formulation of the problem which is both flexible in the sense that it can encapsulate any type of resource required during the handling of a turn-round and strong in the sense that conflicts that occur when two or more turn...

  11. Decontamination of radioactive P[sup 32] and I[sup 131] from aircraft and car surfaces by detergent compositions

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, H.M. (King Abdulazis Military Academy, Dept. of Chemistry, Riyadh (Saudi Arabia)); Badawi, A.M. (Petroleum Research Inst., Dept. of Application, Cairo (Egypt)); Mokhtar, W.M.

    Sheets from aircrafts and cars having the same surfaces were contaminated with solutions of radioactive phosphorus salts and solutions of radioactive iodine salts. Different compositions from synthetic detergents and locally available complexing salts were prepared and their efficiencies in decontaminating the sheets were measured under the same conditions. The most effective compositions were those in which 'Berol Lanco' and 'Nestabon' were used. (orig.)

  12. Nonlinear transient vibrations and coexistences of multi-instabilities induced by friction in an aircraft braking system

    OpenAIRE

    Chevillot, Fabrice; Sinou, Jean-Jacques; Hardouin, Nicolas

    2009-01-01

    International audience Friction-induced vibration is still a cause for concern in a wide variety of mechanical systems, because it can lead to structural damage if high vibration levels are reached. Another effect is the noise produced that can be very unpleasant for end-users, thereby making it a major problem in the field of terrestrial transport. In this work the case of an aircraft braking system is examined. An analytical model with polynomial nonlinearity in the contact between rotor...

  13. 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

  14. Longitudinal Stability Criteria for a Propeller-Driven Aircraft

    OpenAIRE

    Gil Iosilevskii

    2010-01-01

    The Routh criterion is used to assess longitudinal dynamic stability of a propeller-driven aircraft. Under a few plausible assumptions on possible ranges of the pertinent stability derivatives, it reduces to a pair of simple conditions imposing a traditional aft limit (the forward of the maneuver and the neutral-speed-stability points) on the center-of-gravity position and an upper limit on the longitudinal moment of inertia. It is demonstrated that most aircraft have sufficiently small inert...

  15. 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

  16. Small Scale Motions Observed by Aircraft in the Tropical Tropopause Layer - Convective and Non-Convective Environments

    Science.gov (United States)

    Pfister, Leonhard; Bui, T. P.; Dean-Day, J.

    2016-01-01

    Indirect evidence indicates a role for vertical mixing in the Tropical Tropopause Layer (TTL). In particular, detailed model studies suggest that such vertical mixing may be required to explain the value of the water vapor minimum in the TTL. There have been previous observations during the STEP Tropical aircraft campaign (1987) of bursts of high frequency activity associated with convectively generated gravity waves in the tropical western Pacific. Higher frequency, higher quality measurements from NASA high altitude aircraft (ER-2, WB-57, and Global Hawk) have been made available in the last 20 years. These include measurements of vertical velocity and other meteorological parameters. Most recently, during the ATTREX Global Hawk aircraft mission (Airborne Tropical TRopopause EXperiment), there have been extensive measurements at all altitudes of the TTL in both convective (winter western Pacific) and less convective (winter eastern Pacific) regions. This presentation represents an initial analysis of high frequency small scale (a few km max) meteorological measurements from the ATTREX dataset. We obtain some basic information about the distribution and character of high frequency activity in vertical velocity in the TTL. In particular, we focus on relating the high frequency activity to nearby tropical convection and to vertical shears associated with gravity and inertia-gravity waves.

  17. Role of convective transport on tropospheric ozone chemistry revealed by aircraft observations during the wet season of the AMMA campaign

    Directory of Open Access Journals (Sweden)

    G. Ancellet

    2008-08-01

    Full Text Available During the wet season of the African Monsoon Multidisciplinary Analyses (AMMA campaign, airborne measurements of several chemical species were made onboard the French Falcon-20 (FF20 aircraft. The scientific flights were planned in order to document, on one hand the regional distribution of trace gas species related to the oxidizing capacity of the troposphere, and on the other hand their spatial variability in the outflow of mesoscale convective systems (MCSs. The main objectives of this paper are the analysis of the main transport processes responsible for the observed variability, and the discussion of differences and similarities related to the convective transport by 4 different MCSs. This work is needed before using this data set for future studies of the convective transport of chemical species or for modeling work in the frame of the AMMA project. Regarding the regional distribution, five air masses types have been identified using the Lagrangian particle dispersion model FLEXPART, and by considering relationship between the measured trace gas concentrations (O3, CO, NOx, H2O, and hydroperoxides. This paper specifically discusses the advantage of hydroperoxide measurements in order to document the impact of recent or aged convection. The highest values of O3 are found to be related to transport from the subtropical tropopause region into the mid-troposphere at latitudes as low as 10° N. The lowest ozone values have been always explained by recent uplifting from the monsoon layer where O3 is photochemically destroyed. Regarding the analysis of the MCS outflow, the CO and H2O2 enhancements are related to the age and the southernmost position of the MCS. The analysis of the long range transport of the air masses where convection occurred, shows a connection with the Persian Gulf emissions for the largest CO concentrations in MCS outflow. However for our

  18. Aircraft Simulators and Pilot Training.

    Science.gov (United States)

    Caro, Paul W.

    Flight simulators are built as realistically as possible, presumably to enhance their training value. Yet, their training value is determined by the way they are used. Traditionally, simulators have been less important for training than have aircraft, but they are currently emerging as primary pilot training vehicles. This new emphasis is an…

  19. 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...

  20. Analysis of Flight Test Technique on Ground Minimum Control Speed for Civil Aircraft%民机地面最小操纵速度试飞分析及技术

    Institute of Scientific and Technical Information of China (English)

    范祝斌

    2013-01-01

    According to the CCAR-25-R4 “Airworthiness Standards of Transport Category Airplanes” and FAA advisory AC25-7C“Flight Test Guide”, drawing on the flight test experiences of other planes, this paper analyses the flight test principle and impact factors of ground minimum control speed ( VMCG ) in theory, and discusses the flight test technique and the risk alleviated method of VMCG . It can provide guidance for the VMCG flight test of the civil airplane.%按照CCAR-25-R4《运输类飞机适航标准》要求,结合FAA咨询通告AC25-7 C《运输类飞机试飞指南》,总结其它机型的试飞经验,通过理论分析民机地面最小操纵速度( VMCG )试飞原理及影响因素,探讨了民机VMCG试飞的试飞方法及风险规避方法,可为民机的VMCG试飞提供参考。