WorldWideScience

Sample records for landing related aircraft

  1. 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.

  2. Probabilistic model, analysis and computer code for take-off and landing related aircraft crashes into a structure

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, R.

    1996-02-06

    A methodology is presented that allows the calculation of the probability that any of a particular collection of structures will be hit by an aircraft in a take-off or landing related accident during a specified window of time with a velocity exceeding a given critical value. A probabilistic model is developed that incorporates the location of each structure relative to airport runways in the vicinity; the size of the structure; the sizes, types, and frequency of use of commercial, military, and general aviation aircraft which take-off and land at these runways; the relative frequency of take-off and landing related accidents by aircraft type; the stochastic properties of off-runway crashes, namely impact location, impact angle, impact velocity, and the heading, deceleration, and skid distance after impact; and the stochastic properties of runway overruns and runoffs, namely the position at which the aircraft exits the runway, its exit velocity, and the heading and deceleration after exiting. Relevant probability distributions are fitted from extensive commercial, military, and general aviation accident report data bases. The computer source code for implementation of the calculation is provided.

  3. Development and Deployment of Unmanned Aircraft Instrumentation for Measuring Quantities Related to Land Surface-Atmosphere Interactions

    Science.gov (United States)

    de Boer, G.; Lawrence, D.; Elston, J.; Argrow, B. M.; Palo, S. E.; Curry, N.; Finamore, W.; Mack, J.; LoDolce, G.; Schmid, B.; Long, C. N.; Bland, G.; Maslanik, J. A.; Gao, R. S.; Telg, H.; Semmer, S.; Maclean, G.; Ivey, M.; Hock, T. F.; Bartram, B.; Bendure, A.; Stachura, M.

    2015-12-01

    Use of unmanned aircraft systems (UAS) in evaluation of geophysical parameters is expanding at a rapid rate. Despite limitation imposed by necessary regulations related to operation of UAS in the federal airspace, several groups have developed and deployed a variety of UAS and the associated sensors to make measurements of the atmosphere, land surface, ocean and cryosphere. Included in this grouping is work completed at the University of Colorado - Boulder, which has an extended history of operating UAS and expanding their use in the earth sciences. Collaborative projects between the department of Aerospace Engineering, the Cooperative Institute for Research in Environmental Sciences (CIRES), the Research and Engineering Center for Unmanned Vehicles (RECUV), the National Oceanographic and Atmospheric Administration (NOAA) and National Centers for Atmospheric Research (NCAR) have resulted in deployment of UAS to a variety of environments, including the Arctic. In this presentation, I will give an overview of some recent efforts lead by the University of Colorado to develop and deploy a variety of UAS. Work presented will emphasize recent campaigns and instrument development and testing related to understanding the land-atmosphere interface. Specifically, information on systems established for evaluating surface radiation (including albedo), turbulent exchange of water vapor, heat and gasses, and aerosol processes will be presented, along with information on the use of terrestrial ecosystem sensing to provide critical measurments for the evaluation of lower atmospheric flux measurements.

  4. PRINCIPLE "EARLY MATCHING" AERODYNAMIC DESIGN AIRCRAFT WITH LANDING GEAR HOVERCRAFT

    Directory of Open Access Journals (Sweden)

    V. P. Morozov

    2015-01-01

    Full Text Available The principle of "early matching" aircraft aerohydrodynamic layouts with air cushion landing gear is suggested. Application of this principle is considered as an example of adaptation to the ball screw base circuit of light transport aircraft. The principle, other than weight, aerodynamic, technological and operational requirements includes additional project activities related to the installation of ball screws.

  5. Emergency Landing Planning for Damaged Aircraft

    Science.gov (United States)

    Meuleau, Nicolas; Plaunt, Christian John; Smith, David E.

    2008-01-01

    Considerable progress has been made over the last 15 years on building adaptive control systems to assist pilots in flying damaged aircraft. Once a pilot has regained control of a damaged aircraft, the next problem is to determine the best site for an emergency landing. In general, the decision depends on many factors including the actual control envelope of the aircraft, distance to the site, weather en route, characteristics of the approach path, characteristics of the runway or landing site, and emergency facilities at the site. All of these influence the risk to the aircraft, to the passengers and crew, and to people and property on the ground. We describe an ongoing project to build and demonstrate an emergency landing planner that takes these various factors into consideration and proposes possible routes and landing sites to the pilot, ordering them according to estimated risk. We give an overview of the system architecture and input data, describe our preliminary modeling of risk, and describe how we search the space of landing sites and routes.

  6. Concentric circles based simple optical landing aid for vertical takeoff and landing aircrafts

    Science.gov (United States)

    Murshid, Syed H.; Enaya, Rayan; Lovell, Gregory L.

    2014-09-01

    Vertical takeoff and landing (VTOL) aircrafts such as helicopters and drones, add a flexible degree of operation to airborne vehicles. In order to operate these devices in low light situations, where it is difficult to determine slope of the landing surface, a lightweight and standalone device is proposed here. This small optical device can be easily integrated into current VTOL systems. An optical projector consisting of low power, light weight, solid state laser along with minimal optics is utilized to illuminate the landing surface with donut shaped circles and coaxial centralized dot. This device can placed anywhere on the aircraft and a properly placed fiber system can be used to illuminate the surface beneath the bottom of the VTOL aircraft in a fashion that during operation, when the aircraft is parallel to the landing surface, the radius between the central dot and outer ring(s) are equidistant for the entire circumference; however, when there the landing surface of the VTOL aircraft is not parallel to the landing strip, the radial distance between two opposite sides of the circle and central dot will be unequal. The larger this distortion, the greater the difference will be between the opposite sides of the circle. Visual confirmation or other optical devices can be used to determine relative alignment of the projector output allowing the pilot to make proper adjustments as they approach the landing surface to ensure safe landings. Simulated and experimental results from a prototype optical projector are presented here.

  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. NEURAL NETWORK SYSTEM TRACKS LANDING AIRCRAFT WHEN WIND DIRECTION CHANGES

    Directory of Open Access Journals (Sweden)

    G. N. Lebedev

    2015-01-01

    Full Text Available The article describes the problem of solving important practical problems of redistribution of aircraft when landing on a different route of the Moscow air hub in the event of a sudden change of weather conditions. The neural network procedure to set priorities for each aircraft in real time based on dynamic programming is offered. This allowed us to generate lists of vessels for each trace landing and to determine their priority for landing.

  9. Plasma Fairings for Quieting Aircraft Landing Gear Noise Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A major component of airframe noise for commercial transport aircraft is the deployed landing gear. The noise from the gear originates due to complex, unsteady bluff...

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

    Science.gov (United States)

    Ross, I.

    1982-01-01

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

  11. Emission of particulate matter during aircraft landing operation

    Directory of Open Access Journals (Sweden)

    Jasiński Remigiusz

    2016-01-01

    Full Text Available The article presents the results of studies conducted in the area adjacent to the airport located in Poznan, to determine the impact of aircraft landing operation on the concentration of particulate matter. Measurements were carried out using Engine Exhaust Particle Sizer Spectrometer 3090, enabling the measurement of the particle size distribution. The research allowed to determine the nature of the emitted particles and adds to the evaluation of impact on air quality. The tests were carried out during four aircraft landing operations. In each of the four cases total concentration of particulates number before landing (reference level and during the landing of the aircraft was measured. In addition, the size distribution of reference level particles and its change after the landing operation was measured. Based on the conducted research, it was found that landing aircrafts have a significant impact on the concentration of particulate matter in the area adjacent to the airport. A single landing operation causes an substantially increase of the value of particle number concentration.

  12. AGFATL- ACTIVE GEAR FLEXIBLE AIRCRAFT TAKEOFF AND LANDING ANALYSIS

    Science.gov (United States)

    Mcgehee, J. R.

    1994-01-01

    The Active Gear, Flexible Aircraft Takeoff and Landing Analysis program, AGFATL, was developed to provide a complete simulation of the aircraft takeoff and landing dynamics problem. AGFATL can represent an airplane either as a rigid body with six degrees of freedom or as a flexible body with multiple degrees of freedom. The airframe flexibility is represented by the superposition of up to twenty free vibration modes on the rigid-body motions. The analysis includes maneuver logic and autopilots programmed to control the aircraft during glide slope, flare, landing, and takeoff. The program is modular so that performance of the aircraft in flight and during landing and ground maneuvers can be studied separately or in combination. A program restart capability is included in AGFATL. Effects simulated in the AGFATL program include: (1) flexible aircraft control and performance during glide slope, flare, landing roll, and takeoff roll under conditions of changing winds, engine failures, brake failures, control system failures, strut failures, restrictions due to runway length, and control variable limits and time lags; (2) landing gear loads and dynamics for up to five gears; (3) single and multiple engines (maximum of four) including selective engine reversing and failure; (4) drag chute and spoiler effects; (5) wheel braking (including skid-control) and selective brake failure; (6) aerodynamic ground effects; (7) aircraft carrier operations; (8) inclined runways and runway perturbations; (9) flexible or rigid airframes; 10) rudder and nose gear steering; and 11) actively controlled landing gear shock struts. Input to the AGFATL program includes data which describe runway roughness; vehicle geometry, flexibility and aerodynamic characteristics; landing gear(s); propulsion; and initial conditions such as attitude, attitude change rates, and velocities. AGFATL performs a time integration of the equations of motion and outputs comprehensive information on the airframe

  13. The effect of aircraft control forces on pilot performance during instrument landings in a flight simulator.

    Science.gov (United States)

    Hewson, D J; McNair, P J; Marshall, R N

    2001-07-01

    Pilots may have difficulty controlling aircraft at both high and low force levels due to larger variability in force production at these force levels. The aim of this study was to measure the force variability and landing performance of pilots during an instrument landing in a flight simulator. There were 12 pilots who were tested while performing 5 instrument landings in a flight simulator, each of which required different control force inputs. Pilots can produce the least force when pushing the control column to the right, therefore the force levels for the landings were set relative to each pilot's maximum aileron-right force. The force levels for the landings were 90%, 60%, and 30% of maximal aileron-right force, normal force, and 25% of normal force. Variables recorded included electromyographic activity (EMG), aircraft control forces, aircraft attitude, perceived exertion and deviation from glide slope and heading. Multivariate analysis of variance was used to test for differences between landings. Pilots were least accurate in landing performance during the landing at 90% of maximal force (p < 0.05). There was also a trend toward decreased landing performance during the landing at 25% of normal force. Pilots were more variable in force production during the landings at 60% and 90% of maximal force (p < 0.05). Pilots are less accurate at performing instrument landings when control forces are high due to the increased variability of force production. The increase in variability at high force levels is most likely associated with motor unit recruitment, rather than rate coding. Aircraft designers need to consider the reduction in pilot performance at high force levels, as well as pilot strength limits when specifying new standards.

  14. Unmanned Aircraft Systems for Monitoring Department of the Interior Lands

    Science.gov (United States)

    Hutt, M. E.; Quirk, B.

    2013-12-01

    Unmanned Aircraft Systems (UAS) technology is quickly evolving and will have a significant impact on Earth science research. The U.S. Geological Survey (USGS) is conducting an operational test and evaluation of UAS to see how this technology supports the mission of the Department of the Interior (DOI). Over the last 4 years, the USGS, working with many partners, has been actively conducting proof of concept UAS operations, which are designed to evaluate the potential of UAS technology to support the mandated DOI scientific, resource and land management missions. UAS technology is being made available to monitor environmental conditions, analyze the impacts of climate change, respond to natural hazards, understand landscape change rates and consequences, conduct wildlife inventories and support related land management and law enforcement missions. Using small UAS (sUAS), the USGS is able to tailor solutions to meet project requirements by obtaining very high resolution video data, acquiring thermal imagery, detecting chemical plumes, and generating digital terrain models at a fraction of the cost of conventional surveying methods. UAS technology is providing a mechanism to collect timely remote sensing data at a low cost and at low risk over DOI lands that can be difficult to monitor and consequently enhances our ability to provide unbiased scientific information to better enable decision makers to make informed decisions. This presentation describes the UAS technology and infrastructure being employed, the application projects already accomplished, lessons learned and future of UAS within the DOI. We fully expect that by 2020 UAS will emerge as a primary platform for all DOI remote sensing applications. Much like the use of Internet technology, Geographic Information Systems (GIS) and Global Positioning Systems (GPS), UAS have the potential of enabling the DOI to be better stewards of the land.

  15. Research related to variable sweep aircraft development

    Science.gov (United States)

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

    1981-01-01

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

  16. Environmental Influence on Automatic Landing Error of the Carrier-Borne Aircraft

    Directory of Open Access Journals (Sweden)

    Han Zhimin

    2013-03-01

    Full Text Available The aim of this study is to analyze the movement model of aircraft carrier and stern flow model under the influence of marine sport. Also, we focus on the influence of marine sports and aft flow on the landing error of the carrier-borne aircraft under the guidance of the automatic landing system in different sea state level by numerical simulation and calculation. The analysis result is meaningful to the aircraft carrier due to the fact that environmental factors have a great influence on the error of carrier-borne aircraft landing on aircraft carrier, especially; marine sports and aft flow always affect the movement of an aircraft carrier and landing process of carrier-borne aircraft.

  17. Status report on the land processes aircraft science management operations working group

    Science.gov (United States)

    Lawless, James G.; Mann, Lisa J.

    1991-01-01

    Since its inception three years ago, the Land Processes Aircraft Science Management Operations Working Group (MOWG) provided recommendations on the optimal use of the Agency's aircraft in support of the Land Processes Science Program. Recommendations covered topics such as aircraft and sensor usage, development of long-range plans, Multisensor Airborne Campaigns (MAC), program balance, aircraft sensor databases, new technology and sensor development, and increased University scientist participation in the program. Impacts of these recommendations improved the efficiency of various procedures including the flight request process, tracking of flight hours, and aircraft usage. The group also created a bibliography focused on publications produced by Land Processes scientists from the use of the aircraft program, surveyed NASA funded PI's on their participation in the aircraft program, and developed a planning template for multi-sensor airborne campaigns. Benefits from these activities are summarized.

  18. Compound Wing Vertical Takeoff and Landing Small Unmanned Aircraft System

    Science.gov (United States)

    Logan, Michael J. (Inventor); Motter, Mark A. (Inventor); Deloach, Richard (Inventor); Vranas, Thomas L. (Inventor); Prendergast, Joseph M. (Inventor); Lipp, Brittney N. (Inventor)

    2017-01-01

    Systems, methods, and devices are provided that enable robust operations of a small unmanned aircraft system (sUAS) using a compound wing. The various embodiments may provide a sUAS with vertical takeoff and landing capability, long endurance, and the capability to operate in adverse environmental conditions. In the various embodiments a sUAS may include a fuselage and a compound wing comprising a fixed portion coupled to the fuselage, a wing lifting portion outboard of the fixed portion comprising a rigid cross member and a controllable articulating portion configured to rotate controllable through a range of motion from a horizontal position to a vertical position, and a freely rotating wing portion outboard of the wing lifting portion and configured to rotate freely based on wind forces incident on the freely rotating wing portion.

  19. New stabilization design for planar vertical take-off and landing aircrafts

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper presents a new stabilizing control law for a planar vertical take-off and landing aircraft.The model is first transformed into an equivalent form,and then a control law consisting of a linear term and a saturated term is given for a related subsystem,with the saturation levels being assigned as large as possible.Compared to the existing saturation scheme in which all states are restricted by saturations,the design brings about a relatively fast convergence.The effectiveness and advantage of the d...

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

    Science.gov (United States)

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

    2008-10-01

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

  1. Design Of Vertical Take-Off And Landing VTOL Aircraft System

    Directory of Open Access Journals (Sweden)

    Win Ko Ko Oo

    2015-08-01

    Full Text Available Vertical Take Off and Landing Vehicles VTOL are the ones which can take off and land from the same place without need of long runway. This paper presents the design and implementation of tricopter mode and aircraft mode for VTOL aircraft system. Firstly the aircraft design is considered for VTOL mode. And then the mathematical model of the VTOL aircraft is applied to test stability. In this research the KK 2.1 flight controller is used for VTOL mode and aircraft mode. The first part is to develop the VTOL mode and the next part is the transition of VTOL mode to aircraft mode. This paper gives brief idea about numerous types of VTOLs and their advantages over traditional aircraftsand insight to various types of tricopter and evaluates their configurations.

  2. Numerical and Experimental Investigation of the Structural Behavior during Aircraft Emergency Landing on Water

    OpenAIRE

    Siemann, Martin

    2016-01-01

    Although occurring infrequent, the emergency landing of aircraft on water constitutes a crucial facet within aviation safety and, hence, it engages aircraft manufacturers within design and certification processes. Currently employed methods to analyze ditching comprise experimental testing, comparison with already ditching-certified aircraft designs, and semi-analytical as well as uncoupled numerical simulations. Since these means comprise several drawbacks and limitations, there is the motiv...

  3. Wake Vortices of Landing Aircraft, in High Performance Computing in Science and Engineering

    OpenAIRE

    Holzäpfel, Frank; Stephan, Anton; Heel, Tobias

    2014-01-01

    As an unavoidable consequence of lift aircraft generate a pair of counter-rotating and long-lived wake vortices that pose a potential risk to following aircraft. The prescribed aircraft separations during landing to avoid wake vortex hazards contribute significantly to capacity restrictions of large airports. Severe encounters of wake vortices have also been reported during cruise. Wake vortex behavior is largely controlled by the prevailing meteorological conditions a...

  4. 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.

  5. Aircraft

    Science.gov (United States)

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

    1998-09-22

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

  6. In flight image processing on multi-rotor aircraft for autonomous landing

    Science.gov (United States)

    Henry, Richard, Jr.

    An estimated $6.4 billion was spent during the year 2013 on developing drone technology around the world and is expected to double in the next decade. However, drone applications typically require strong pilot skills, safety, responsibilities and adherence to regulations during flight. If the flight control process could be safer and more reliable in terms of landing, it would be possible to further develop a wider range of applications. The objective of this research effort is to describe the design and evaluation of a fully autonomous Unmanned Aerial system (UAS), specifically a four rotor aircraft, commonly known as quad copter for precise landing applications. The full landing autonomy is achieved by image processing capabilities during flight for target recognition by employing the open source library OpenCV. In addition, all imaging data is processed by a single embedded computer that estimates a relative position with respect to the target landing pad. Results shows a reduction on the average offset error by 67.88% in comparison to the current return to lunch (RTL) method which only relies on GPS positioning. The present work validates the need for relying on image processing for precise landing applications instead of the inexact method of a commercial low cost GPS dependency.

  7. Effects of higher order control systems on aircraft approach and landing longitudinal handling qualities

    Science.gov (United States)

    Pasha, M. A.; Dazzo, J. J.; Silverthorn, J. T.

    1982-01-01

    An investigation of approach and landing longitudinal flying qualities, based on data generated using a variable stability NT-33 aircraft combined with significant control system dynamics is described. An optimum pilot lead time for pitch tracking, flight path angle tracking, and combined pitch and flight path angle tracking tasks is determined from a closed loop simulation using integral squared error (ISE) as a performance measure. Pilot gain and lead time were varied in the closed loop simulation of the pilot and aircraft to obtain the best performance for different control system configurations. The results lead to the selection of an optimum lead time using ISE as a performance criterion. Using this value of optimum lead time, a correlation is then found between pilot rating and performance with changes in the control system and in the aircraft dynamics. It is also shown that pilot rating is closely related to pilot workload which, in turn, is related to the amount of lead which the pilot must generate to obtain satisfactory response. The results also indicate that the pilot may use pitch angle tracking for the approach task and then add flight path angle tracking for the flare and touchdown.

  8. Effects of higher order control systems on aircraft approach and landing longitudinal handling qualities

    Science.gov (United States)

    Pasha, M. A.; Dazzo, J. J.; Silverthorn, J. T.

    1982-01-01

    An investigation of approach and landing longitudinal flying qualities, based on data generated using a variable stability NT-33 aircraft combined with significant control system dynamics is described. An optimum pilot lead time for pitch tracking, flight path angle tracking, and combined pitch and flight path angle tracking tasks is determined from a closed loop simulation using integral squared error (ISE) as a performance measure. Pilot gain and lead time were varied in the closed loop simulation of the pilot and aircraft to obtain the best performance for different control system configurations. The results lead to the selection of an optimum lead time using ISE as a performance criterion. Using this value of optimum lead time, a correlation is then found between pilot rating and performance with changes in the control system and in the aircraft dynamics. It is also shown that pilot rating is closely related to pilot workload which, in turn, is related to the amount of lead which the pilot must generate to obtain satisfactory response. The results also indicate that the pilot may use pitch angle tracking for the approach task and then add flight path angle tracking for the flare and touchdown.

  9. 22 CFR 121.3 - Aircraft and related articles.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Aircraft and related articles. 121.3 Section 121.3 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS THE UNITED STATES MUNITIONS LIST Enumeration of Articles § 121.3 Aircraft and related articles. In Category...

  10. Microphysical Properties of Warm Clouds During The Aircraft Take-Off and Landing Over Bucharest, Romania

    Science.gov (United States)

    Stefan, Sabina; Nicolae Vajaiac, Sorin; Boscornea, Andreea

    2016-06-01

    This paper is focused on airborne measurements of microphysical parameters into warm clouds when the aircraft penetrates the cloud, both during take-off and landing. The experiment was conducted during the aircraft flight between Bucharest and Craiova, in the southern part of Romania. The duration of the experimental flight was 2 hours and 35 minutes in October 7th, 2014, but the present study is dealing solely with the analysis of cloud microphysical properties at the beginning of the experiment (during the aircraft take-off) and at the end, when it got finalized by the aircraft landing procedure. The processing and interpretation of the measurements showed the differences between microphysical parameters, emphasizing that the type of cloud over Bucharest changed, as it was expected. In addition, the results showed that it is important to take into account both the synoptic context and the cloud perturbation due to the velocity of the aircraft, in such cases.

  11. A novel trajectory planning strategy for aircraft emergency landing using Gauss pseudospectral method

    Institute of Scientific and Technical Information of China (English)

    Shaohua MENG; Jinwu XIANG; Zhangping LUO; Yiru REN; Nanjian ZHUANG

    2014-01-01

    To improve the survivability during an emergency situation, an algorithm for aircraft forced landing trajectory planning is proposed. The method integrates damaged aircraft modelling and trajectory planning into an optimal control framework. In order to deal with the complex aircraft flight dynamics, a solving strategy based on Gauss pseudospetral method (GPM) is presented. A 3-DOF nonlinear mass-point model taking into account the wind is developed to approximate the aircraft flight dynamics after loss of thrust. The solution minimizes the forced landing duration, with respect to the constraints that translate the changed dynamics, flight envelope limitation and operational safety requirements. The GPM is used to convert the trajectory planning problem to a nonlinear programming problem (NLP), which is solved by sequential quadratic programming algorithm. Simulation results show that the proposed algorithm can generate the minimum-time forced landing trajectory in event of engine-out with high efficiency and precision.

  12. Aircraft noise exposure from Schiphol airport: A relation with complainants

    NARCIS (Netherlands)

    Jong, R.G. de; Wiechen, C.M.A.G. van; Franssen, E.A.M.; Lebret, E.

    2002-01-01

    The possible relation between aircraft noise exposure and the prevalence of complainants around Schiphol airport was studied. The home address of people who complain about aircraft noise at the Environment Advisory Committee Schiphol was combined with annual average noise levels, using a Geographic

  13. Study on the control course of ANFIS based aircraft auto-landing

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The control model in the course of an aircraft auto-landing is first proposed. Then, the common basic hypotheses in the design of a fuzzy logic controller are described. The fuzzy inference system of an aircraft auto-landing fuzzy controller in the course of automatic control on landing is investigated. The auto-landing model for controlling, membership functions of state variables, inference rules in the system, algorithms for fuzzy inference and defuzzification, etc, are analyzed and devised in detail with the emphasis on optimal analysis and design of Takagi-Sugeno ALFC based on adaptive neural fuzzy inference systems. Finally, the simulation for verification and analysis of the designed schemes is made by utilizing Simulink and fuzzy logic toolbox with MATLAB. The simulated results show that the ANFIS based T-S type ALFC scheme has excellent behavior in performance.

  14. Hybrid Genetic-cuckoo Search Algorithm for Solving Runway Dependent Aircraft Landing Problem

    Directory of Open Access Journals (Sweden)

    Peigang Guo

    2013-07-01

    Full Text Available As the demand for air transportation continues to grow, some flights cannot land at their preferred landing times because the airport is near its runway capacity. Therefore, devising a method for tackling the Aircraft Landing Problem (ALP in order to optimize the usage of existing runways at airports is the focus of this study. This study, a hybrid Genetic-Cuckoo Search (GCS algorithm for optimization the ALP with runway is proposed. The numerical results showed that the proposed GCS algorithm can effectively and efficiently determine the runway allocation, sequence and landing time for arriving aircraft for the three test cases by minimizing total delays under the separation constraints in comparison with the outcomes yielded by previous studies.

  15. House attenuation of aircraft and street traffic noise in relation to annoyance: A pilot study

    Science.gov (United States)

    Kryter, Karl D.

    2001-05-01

    House barrier sound attenuation was measured as differences between the levels of street traffic and aircraft noise found outdoors near the front (street facing) and rear façades, and in rooms of two one-story houses. Also, attenuation of street traffic and aircraft noise between the front and rear façades of similar one-story houses was calculated in accordance with acoustical models. Findings: (1) relative to levels measured near the front façade, street traffic noise near the rear façade, and in rooms inside the houses, was, on average, 9 max dB and 8 SEL dB more attenuated than was aircraft noise. (2) When attenuation of street traffic noise was measured relative to its level near the front façade, and attenuation for aircraft noise was measured relative to its level near the rear façade, street traffic noise was, on average, 7 max dB and 6 SEL dB more attenuated than aircraft noise. (3) Calculated barrier attenuation of street traffic noise was, on average, 1.3 max dB less than measured; calculated barrier attenuation of aircraft noise differed from measured by ~0.4 max dB. Implications of the findings for guidelines for assessing impact of these noises on communities and land-use zoning are discussed.

  16. Plasma Fairings for Quieting Aircraft Landing Gear Noise Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase II SBIR project deals with the design, development, and testing of a "Plasma Fairing" to reduce noise on the Gulfstream G550 landing gear. The plasma...

  17. 14 CFR 135.183 - Performance requirements: Land aircraft operated over water.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Performance requirements: Land aircraft operated over water. 135.183 Section 135.183 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... AND OPERATIONS OPERATING REQUIREMENTS: COMMUTER AND ON DEMAND OPERATIONS AND RULES GOVERNING...

  18. MATHEMATICAL ASPECTS OF AIRCRAFT ENGINES RUNNING OPTIMIZATION FOR MINIMUM FUEL CONSUMPTION WHILE LANDING

    Directory of Open Access Journals (Sweden)

    Yuriy Michaylovich Chinyuchin

    2017-01-01

    Full Text Available The consistency of the potential increase of fuel efficiency, based on aircraft maintenance optimization, is mathe- matically proved. The mathematical apparatus and a set mathematical model of aircraft spatial motion allow to analyze aircraft behavior on the stage before landing and to draw optimal flight path for minimum fuel consumption with fixed time.For effective problem solving the choice and realization of optimal flight paths are made. The algorithm for the problem of optimal civil aircraft flight control aimed at the most accurate realization of chosen soft path under limited time conditions is proposed. The optimization of the given process is made by solving a point-to-point boundary canonical sys- tem based on the Pontryagin maximum principle.The necessary initial data and conditions for the statement of problem are given. The mathematical model for the simplification of calculations is created and its equivalent representation is given by uniting problems of controls by thrust channels and the angle of attack as the thrust control function. The boundary-value problem is mathematically composed and the analytical apparatus of its solution is presented. Optimal aircraft landing paths reflecting the behavior of the angle of attack and thrust are constructed. The potential of this method is proved by the economic justifiability and its effectiveness, in particular the compar- ison of total aircraft fuel consumption on obtained optimal path to the classic path on which there are rectilinear sections what allowed to confirm the conclusion about the economical expedience and effectiveness of the method of aircraft con- stant landing while making flights.

  19. Analysis of Aircraft Fuels and Related Materials

    Science.gov (United States)

    1982-09-01

    electrical charges can be generated when fuel is added to aircraft fuel tanks containing reticulated polyurethane foam. On several occasions electrical...to be a mixture of cellulose and synthetic fibers plus pieces of fuel tank foam. These materials, however, were not specifically characterized. The...oxides. The presence of inorganic carbonate is also suggested by a weak band at approxi- mately 7 microns. The presence of some cellulose from scraping

  20. Real-time radar signal processing for autonomous aircraft landing

    Science.gov (United States)

    Sadjadi, Firooz A.; Helgeson, Michael A.; Radke, Jeffrey D.; Stein, Gunter

    1993-11-01

    Landing in poor weather is a crucial problem for the air transportation system. To aid the pilots for these conditions several solutions have been suggested and/or implemented including instrument landing systems (ILS) and microwave landing systems (MLS) that put the responsibility of the landing to a large extent in the hands of the airport facilities. These systems even though useful are not available due to their high costs even in a few major metropolitan airports. This shortcoming has generated interest in providing all weather capabilities not on the landing facility but on the vehicle itself. The Synthetic Vision System Technology Demonstration sponsored by the United States Federal Aviation Administration (FAA) and the U.S. Air Force represents an effort to respond to the above needs. In this paper we present a summary of a typical synthetic vision system. This system consists of a scanning 35 GHz radar, a scanning antenna, a signal/image processor and a head up display (HUD). The pilot is presented a final perspective image of the scene sensed by the radar with associated flight guidance symbology. This system is implemented in real time hardware and has been undergoing tower and flight testing under a variety of weather conditions since early 1992.

  1. Magnetic levitation assisted aircraft take-off and landing (feasibility study - GABRIEL concept)

    Science.gov (United States)

    Rohacs, Daniel; Rohacs, Jozsef

    2016-08-01

    The Technology Roadmap 2013 developed by the International Air Transport Association envisions the option of flying without an undercarriage to be in operation by 2032. Preliminary investigations clearly indicate that magnetic levitation technology (MagLev) might be an appealing solution to assist the aircraft take-off and landing. The EU supported research project, abbreviated as GABRIEL, was dealing with (i) the concept development, (ii) the identification, evaluation and selection of the deployable magnetic levitation technology, (iii) the definition of the core system elements (including the required aircraft modifications, the ground-based system and airport elements, and the rendezvous control system), (iv) the analysis of the safety and security aspects, (v) the concept validation and (vi) the estimation of the proposed concept impact in terms of aircraft weight, noise, emission, cost-benefit). All results introduced here are compared to a medium size hypothetic passenger aircraft (identical with an Airbus A320). This paper gives a systematic overview of (i) the applied methods, (ii) the investigation of the possible use of magnetic levitation technology to assist the commercial aircraft take-off and landing processes and (iii) the demonstrations, validations showing the feasibility of the radically new concept. All major results are outlined.

  2. Hover performance estimation and validation of battery powered vertical takeoff and landing aircraft

    Institute of Scientific and Technical Information of China (English)

    王波; 侯中喜; 鲁亚飞; 朱雄峰

    2016-01-01

    Battery powered vertical takeoff and landing (VTOL) aircraft attracts more and more interests from public, while limited hover endurance hinders many prospective applications. Based on the weight models of battery, motor and electronic speed controller, the power consumption model of propeller and the constant power discharge model of battery, an efficient method to estimate the hover endurance of battery powered VTOL aircraft was presented. In order to understand the mechanism of performance improvement, the impacts of propulsion system parameters on hover endurance were analyzed by simulations, including the motor power density, the battery capacity, specific energy and Peukert coefficient. Ground experiment platform was established and validation experiments were carried out, the results of which showed a well agreement with the simulations. The estimation method and the analysis results could be used for optimization design and hover performance evaluation of battery powered VTOL aircraft.

  3. Planar equations of rollout motion for an aircraft with free or steerable landing gears

    Science.gov (United States)

    Sleeper, R. K.; Smith, E. G.

    1982-01-01

    Equations were derived for an aircraft in a three-point attitude. Transient tire forces were simulated by delaying the application of forces derived from steady-state considerations. Predicted rollout trajectories were similar to those measured in tests of a small-scale landing-gear model equipped with pneumatic tires (where a laterally sloping runway was used to simulate a crosswind), both with and without nose-wheel steering.

  4. 飞机起落架系统简介%Introduction to aircraft landing gear system

    Institute of Scientific and Technical Information of China (English)

    陈永新

    2014-01-01

    简单介绍飞机起落架的作用、配置形式、结构形式、组成、发展历史,使非起落架专业人士对起落架有所了解。%Brief introduces aircraft landing gear function, configuration form, structure, composition, history, so that non-professionals know something about it.

  5. Microphysical characteristics of convective clouds over ocean and land from aircraft observations

    Science.gov (United States)

    Padmakumari, B.; Maheskumar, R. S.; Anand, Vrinda; Axisa, Duncan

    2017-10-01

    The Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) is a field campaign conducted in India with an instrumented research aircraft. On 29 October 2010, a cyclonic circulation over the Bay of Bengal persisted throughout the day. A special mission was conducted over the Bay of Bengal on this day with the objective of characterizing marine and continental clouds on the same day and finding contrasting/similar signatures of their microphysical properties. The research aircraft sampled growing convective clouds over the ocean and over land. High concentrations of aerosol and cloud condensation nuclei (CCN) were observed over land compared to ocean. Over ocean, higher liquid water content (LWC) and lower cloud droplet number concentrations (Nc) were observed, and droplets reached the threshold of precipitation initiation at lower cloud depths. Over land, clouds contained lower LWC and higher Nc, hence droplets did not reach the threshold of precipitation initiation at a warm temperature as in ocean clouds. Over the ocean larger droplets or drizzle were observed at lower cloud depth than over land. The maximum LWC was found to be very similar at higher altitudes. The convective clouds over land were modified by pollution aerosol with contrasting microphysical properties to those over the ocean.

  6. Methods for predicting unsteady takeoff and landing trajectories of the aircraft

    Science.gov (United States)

    Shevchenko, A.; Pavlov, B.; Nachinkina, G.

    2017-01-01

    Informational and situational awareness of the aircrew greatly affects the probability of accidents, during takeoff and landing in particular. For the purpose of assessing the current and predicting the future states of an aircraft the energy approach to the flight control is used. Key energy balance equation is generalized to the ground phases. The equation describes the process of accumulating of the total energy of the aircraft along the entire trajectory, including the segment ahead. This segment length is defined by the required terminal energy state. For the takeoff phase the predict algorithm calculates the aircraft position on a runway after which it is possible to accelerate up to the speed of steady level flight and to reach the altitude sufficient for overcoming the high-rise obstacles. For the landing phase the braking distance length is determined. For increasing the likelihood of predicting the correction of the algorithm is introduced. The results of modeling many takeoffs and landings of passenger liner with different weights with the ahead obstacle and the engine failure are given. Working availability of the algorithm correction is shown.

  7. Application of the concept of dynamic trim control to automatic landing of carrier aircraft. [utilizing digital feedforeward control

    Science.gov (United States)

    Smith, G. A.; Meyer, G.

    1980-01-01

    The results of a simulation study of an alternative design concept for an automatic landing control system are presented. The alternative design concept for an automatic landing control system is described. The design concept is the total aircraft flight control system (TAFCOS). TAFCOS is an open loop, feed forward system that commands the proper instantaneous thrust, angle of attack, and roll angle to achieve the forces required to follow the desired trajector. These dynamic trim conditions are determined by an inversion of the aircraft nonlinear force characteristics. The concept was applied to an A-7E aircraft approaching an aircraft carrier. The implementation details with an airborne digital computer are discussed. The automatic carrier landing situation is described. The simulation results are presented for a carrier approach with atmospheric disturbances, an approach with no disturbances, and for tailwind and headwind gusts.

  8. Control of an electro-hydrostatic actuation system for the nose landing gear of an "all electric aircraft"

    OpenAIRE

    Greissner, Carsten; Carl, Udo

    2004-01-01

    The EU research Project Power Optimised Aircraft (POA) investigates the approach to replace primary hydraulic supply by extended electric power systems towards a More or All Electric Aircraft. This contribution presents an electrically powered actuation system for nose landing gears using an EHA (electrohydrostatic actuator) approach. One motor pump unit supplies door and gear actuation as well as the steering system. Different control strategies for the individual actuators are introduced. T...

  9. Terahertz-based relative positioning of aircraft flying in formation

    Science.gov (United States)

    Parker, John Scott

    This thesis introduces a new method for estimating the relative positions of aircraft flying in formation using terahertz frequency (THz) signals. We look specifically at the military precision airdrop application, where THz signals have two advantages: (1) stealth due to preferential propagation in the horizontal direction at high altitudes and (2) robustness for operations in GPS-denied environments. This thesis presents two system concepts for implementation. The first, dubbed the straight-and-level (SAL) architecture, produces high precision position estimates during straight and level flight, but suffers from systematic biases when the receiving aircraft performs a maneuver. In support of this architecture, we published the first ever paper on THz relative positioning, and introduced a new filtering method inspired by the well-known GPS Hatch Filter. The second, dubbed the refined-for-maneuvers (RFM) architecture, produces position estimates that are less precise than the SAL architecture, but have no systematic bias when the aircraft maneuver. Simulations are used to predict the performance of the architectures.

  10. Analysis of modern problems and state of land relations

    Directory of Open Access Journals (Sweden)

    Т. В. Козлова

    2013-07-01

    Full Text Available Problems of the current situation of land relations and public land policy in Ukraine are investigated. Key factors that cause inhibition of land reform are identified. It was noted that public land policy today does not correspond to the full European and world standards and requirements of effective land management, so creating modern public land management is the main task, which will create a clear mechanism for land relations regulation. It was found that land issues can not be seen in isolation from the complex related to social, economic, environmental and legal issues. The measures to be implemented at this stage of land reform are proposed.

  11. 31 CFR 585.208 - Prohibited overflights, takeoffs and landings of aircraft en route to or from the FRY (S&M).

    Science.gov (United States)

    2010-07-01

    ... landings of aircraft en route to or from the FRY (S&M). 585.208 Section 585.208 Money and Finance: Treasury..., takeoffs and landings of aircraft en route to or from the FRY (S&M). Except as otherwise authorized, no... off from the territory of the FRY (S&M). See also: Special Federal Aviation Regulation (SFAR) No....

  12. Development of an Integrated Digital Elevation Model for Safe Takeoff and Landing of the Aircraft

    Science.gov (United States)

    Ciećko, Adam; Jarmołowski, Wojciech

    2013-12-01

    The article describes preliminary results of the augmentation of Global Navigation Satellite System/Inertial Navigation System positioning (GNSS/INS) by Digital Elevation Model (DEM) based on the data from the Shuttle Radar Topography Mission (SRTM) and data from field survey. The prototype software is developed to refer the position of the aircraft to DEM and informs the user about the current relevant flight parameters. The number of the parameters may be arbitrarily increased, however, currently we investigate the altitude above the terrain and the aircraft position relative to the descent path and airfield. The study provides some information on the local SRTM accuracy in relation to the field survey of the airfield "Dajtki" - Aeroclub of Warmia and Mazury in Olsztyn.

  13. Downscaling of Aircraft-, Landsat-, and MODIS-based Land Surface Temperature Images with Support Vector Machines

    Science.gov (United States)

    Ha, W.; Gowda, P. H.; Oommen, T.; Howell, T. A.; Hernandez, J. E.

    2010-12-01

    High spatial resolution Land Surface Temperature (LST) images are required to estimate evapotranspiration (ET) at a field scale for irrigation scheduling purposes. Satellite sensors such as Landsat 5 Thematic Mapper (TM) and Moderate Resolution Imaging Spectroradiometer (MODIS) can offer images at several spectral bandwidths including visible, near-infrared (NIR), shortwave-infrared, and thermal-infrared (TIR). The TIR images usually have coarser spatial resolutions than those from non-thermal infrared bands. Due to this technical constraint of the satellite sensors on these platforms, image downscaling has been proposed in the field of ET remote sensing. This paper explores the potential of the Support Vector Machines (SVM) to perform downscaling of LST images derived from aircraft (4 m spatial resolution), TM (120 m), and MODIS (1000 m) using normalized difference vegetation index images derived from simultaneously acquired high resolution visible and NIR data (1 m for aircraft, 30 m for TM, and 250 m for MODIS). The SVM is a new generation machine learning algorithm that has found a wide application in the field of pattern recognition and time series analysis. The SVM would be ideally suited for downscaling problems due to its generalization ability in capturing non-linear regression relationship between the predictand and the multiple predictors. Remote sensing data acquired over the Texas High Plains during the 2008 summer growing season will be used in this study. Accuracy assessment of the downscaled 1, 30, and 250 m LST images will be made by comparing them with LST data measured with infrared thermometers at a small spatial scale, upscaled 30 m aircraft-based LST images, and upscaled 250 m TM-based LST images, respectively.

  14. Flight evaluation of configuration management system concepts during transition to the landing approach for a powered-lift STOL aircraft

    Science.gov (United States)

    Franklin, J. A.; Innis, R. C.

    1980-01-01

    Flight experiments were conducted to evaluate two control concepts for configuration management during the transition to landing approach for a powered-lift STOL aircraft. NASA Ames' augmentor wing research aircraft was used in the program. Transitions from nominal level-flight configurations at terminal area pattern speeds were conducted along straight and curved descending flightpaths. Stabilization and command augmentation for attitude and airspeed control were used in conjunction with a three-cue flight director that presented commands for pitch, roll, and throttle controls. A prototype microwave system provided landing guidance. Results of these flight experiments indicate that these configuration management concepts permit the successful performance of transitions and approaches along curved paths by powered-lift STOL aircraft. Flight director guidance was essential to accomplish the task.

  15. Sharing scarcity : land access and social relations in Southeast Rwanda

    NARCIS (Netherlands)

    Leegwater, M.

    2015-01-01

    Land is a crucial yet scarce resource in Rwanda, where about 90% of the population is engaged in subsistence farming, and access to land is increasingly becoming a source of conflict. This study examines the effects of land-access and land-tenure policies on local community relations, including ethn

  16. Flight evaluation of highly augmented controls and electronic displays for precision approach and landing of powered-lift aircraft

    Science.gov (United States)

    Franklin, J. A.; Hynes, C. S.

    1985-01-01

    Experiments were conducted on simulators and on the Quiet Short-Haul Research Aircraft to evaluate the effect of highly augmented control modes and electronic displays on the ability of pilots to execute precision approaches and landings on a short runway. It is found that the primary benefits of highly augmented flightpath and airspeed controls and electronic displays are realized when the pilot is required to execute precisely a complex transition and approach under instrument conditions and in the presence of a wide range of wind and turbulence conditions. A flightpath and airspeed command and stabilization system incorporating nonlinear, inverse system concepts produced fully satisfactory flightpath control throughout the aircraft's terminal operating envelope.

  17. 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.

  18. Design of an aircraft landing system using dual-frequency GNSS

    Science.gov (United States)

    Konno, Hiroyuki

    There is a strong demand for new all-weather navigation aids to support aircraft precision approach and landing. The Federal Aviation Administration's Local Area Augmentation System (LAAS) is one such navigation aid that uses the Global Positioning System (GPS) to estimate aircraft location. LAAS is required to provide very high levels of accuracy, integrity, continuity, and availability, and the integrity requirement of one undetected navigation failure in a billion approaches has been a critical challenge in the design of this system. Tremendous efforts have developed methods to guarantee integrity for various potential anomalies that might threaten LAAS-aided landing. Currently, almost all these risks are mitigated by existing methods. One issue that remains is the risk due to ionosphere anomalies. This dissertation introduces novel integrity algorithms for ionosphere anomalies that take advantage of GPS modernization---undergoing changes in the GPS system that enhance civil user capabilities. This modernization includes adding new GPS civil signals, and these signals make possible multiple-frequency techniques. This research focuses on two types of dual-frequency carrier-smoothing methods---Divergence-Free Smoothing and Ionosphere-Free Smoothing---and develops integrity algorithms for ionosphere anomalies using these methods. Simulations show that the first algorithm, using Ionosphere-Free Smoothing, can achieve 96% to 99.9% availability at best over a broad region of the Conterminous United States (CONUS). This level of availability is unacceptably low for practical use. However, a benefit is that the resulting availability is not a function of the ionosphere condition. The second algorithm, based on Divergence-Free Smoothing, is shown by simulations to achieve more than 99.9% availability over more than 70% of CONUS under nominal ionosphere conditions. However, it has the potential to completely lose availability under severe ionosphere conditions. Taking

  19. Evaluation of Direct Diode Laser Deposited Stainless Steel 316L on 4340 Steel Substrate for Aircraft Landing Gear Application

    Science.gov (United States)

    2010-03-01

    AFRL-RX-WP-TP-2010-4149 EVALUATION OF DIRECT DIODE LASER DEPOSITED STAINLESS STEEL 316L ON 4340 STEEL SUBSTRATE FOR AIRCRAFT LANDING GEAR...March 2010 – 01 March 2010 4. TITLE AND SUBTITLE EVALUATION OF DIRECT DIODE LASER DEPOSITED STAINLESS STEEL 316L ON 4340 STEEL SUBSTRATE FOR...Code) N/A Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39-18 Evaluation of Direct Diode Laser Deposited Stainless Steel 316L on

  20. Morphometric Characteristics of Ice and Snow in the Arctic Basin: Aircraft Landing Observations from the Former Soviet Union, 1928-1989

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains sea ice and snow measurements collected during aircraft landings associated with the Soviet Union's historical Sever airborne and North Pole...

  1. Operational Land Imager relative radiometric calibration

    Science.gov (United States)

    Barsi, Julia A.; Markham, Brian L.

    2015-09-01

    The Operational Land Imager (OLI), on board the Landsat-8 satellite, is a pushbroom sensor with nearly 7000 detectors per band, divided between 14 separate modules. While rigorously characterized prior to launch, the shear number of individual detectors presents a challenge to maintaining the on-orbit relative calibration, such that stripes, bands and other artifacts are minimized in the final image products. On-orbit relative calibration of the OLI is primarily monitored and corrected by observing an on-board primary solar diffuser panel. The panel is the most uniform target available to the OLI, though as observed but the OLI, it has a slope across the field of view due to view angle effects. Just after launch, parameters were derived using the solar diffuser data, to correct for the angular effects across the 14 modules. The residual discontinuities between arrays and the detector-to-detector uniformity continue to be monitored on a weekly basis. The observed variations in the responses to the diffuser panel since launch are thought to be due to real instrument changes. Since launch, the Coastal/Aerosol (CA) and Blue bands have shown the most variation in relative calibration of the VNIR bands, with as much as 0.14% change (3-sigma) between consecutive relative gain estimates. The other VNIR bands (Green, Red and NIR) initially had detectors showing a slow drift of about 0.2% per year, though this stopped after an instrument power cycle about seven months after launch. The SWIR bands also exhibit variability between collects (0.11% 3-sigma) but the larger changes have been where individual detectors' responses change suddenly by as much as 1.5%. The mechanisms behind these changes are not well understood but in order to minimize impact to the users, the OLI relative calibration is updated on a quarterly basis in order to capture changes over time.

  2. Variable Geometry Aircraft Pylon Structure and Related Operation Techniques

    Science.gov (United States)

    Shah, Parthiv N. (Inventor)

    2014-01-01

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

  3. Development of SCR Aircraft takeoff and landing procedures for community noise abatement and their impact on flight safety

    Science.gov (United States)

    Grantham, W. D.; Smith, P. M.

    1980-01-01

    Piloted simulator studies to determine takeoff and landing procedures for a supersonic cruise transport concept that result in predicted community noise levels which meet current Federal Aviation Administration (FAA) standards are discussed. The results indicate that with the use of advanced procedures, the subject simulated aircraft meets the FAA traded noise levels during takeoff and landing utilizing average flight crew skills. The advanced takeoff procedures developed involved violating three of the current Federal Aviation Regulations (FAR) noise test conditions. These were: (1) thrust cutbacks at altitudes below 214 meters (700 ft); (2) thrust cutback level below those presently allowed; and (3) configuration change, other than raising the landing gear. It was not necessary to violate any FAR noise test conditions during landing approach. It was determined that the advanced procedures developed do not compromise flight safety. Automation of some of the aircraft functions reduced pilot workload, and the development of a simple head-up display to assist in the takeoff flight mode proved to be adequate.

  4. Relative receiver autonomous integrity monitoring for future GNSS-based aircraft navigation

    Science.gov (United States)

    Gratton, Livio Rafael

    The Global Positioning System (GPS) has enabled reliable, safe, and practical aircraft positioning for en-route and non-precision phases of flight for more than a decade. Intense research is currently devoted to extending the use of Global Navigation Satellite Systems (GNSS), including GPS, to precision approach and landing operations. In this context, this work is focused on the development, analysis, and verification of the concept of Relative Receiver Autonomous Integrity Monitoring (RRAIM) and its potential applications to precision approach navigation. RRAIM fault detection algorithms are developed, and associated mathematical bounds on position error are derived. These are investigated as possible solutions to some current key challenges in precision approach navigation, discussed below. Augmentation systems serving continent-size areas (like the Wide Area Augmentation System or WAAS) allow certain precision approach operations within the covered region. More and better satellites, with dual frequency capabilities, are expected to be in orbit in the mid-term future, which will potentially allow WAAS-like capabilities worldwide with a sparse ground station network. Two main challenges in achieving this goal are (1) ensuring that navigation fault detection functions are fast enough to alert worldwide users of hazardously misleading information, and (2) minimizing situations in which navigation is unavailable because the user's local satellite geometry is insufficient for safe position estimation. Local augmentation systems (implemented at individual airports, like the Local Area Augmentation System or LAAS) have the potential to allow precision approach and landing operations by providing precise corrections to user-satellite range measurements. An exception to these capabilities arises during ionospheric storms (caused by solar activity), when hazardous situations can exist with residual range errors several orders of magnitudes higher than nominal. Until dual

  5. A mathematical model for Vertical Attitude Takeoff and Landing (VATOL) aircraft simulation. Volume 2: Model equations and base aircraft data

    Science.gov (United States)

    Fortenbaugh, R. L.

    1980-01-01

    Equations incorporated in a VATOL six degree of freedom off-line digital simulation program and data for the Vought SF-121 VATOL aircraft concept which served as the baseline for the development of this program are presented. The equations and data are intended to facilitate the development of a piloted VATOL simulation. The equation presentation format is to state the equations which define a particular model segment. Listings of constants required to quantify the model segment, input variables required to exercise the model segment, and output variables required by other model segments are included. In several instances a series of input or output variables are followed by a section number in parentheses which identifies the model segment of origination or termination of those variables.

  6. Influence of Land Related Factors on Sustainable Land Management in the Ethiopian Highlands

    Science.gov (United States)

    Teshome, Akalu; de Graaff, Jan; Ritsema, Coen

    2014-05-01

    Land is a scarce resource in the highlands of Ethiopia. Its sustainable use is highly affected among other factors by bio-physical and institutional aspects of land. The purpose of this research is to investigate the influence of land quality, land fragmentation and tenure systems on interrelated sustainable land management (SLM) investments in the North Western Ethiopian Highlands. A multivariate probit regression model is used to analyse interdependent investment decisions of SLM practices using a multiple parcel-level observations. The analysis indicates that farmers invest a combination of practices at parcels levels by considering substitution and complementarity effects of the practices. The results also reveal that land quality (e.g. slope and soil fertility status), land fragmentation (parcel size and distance of parcel from homestead) and tenure arrangements influence farmers' investments in SLM practices. The overall results indicate that farm land attributes promote or hinder investments, and tenure systems regulate the decisions about investments. Policy makers should take into consideration these various land related factors in designing and implementing SLM policies and programmes. Key words: Land quality, land fragmentation, tenure arrangements, sustainable land management, multivariate probit

  7. Pitch attitude, flight path, and airspeed control during approach and landing of a powered lift STOL aircraft

    Science.gov (United States)

    Franklin, J. A.; Innis, R. C.

    1972-01-01

    Analytical investigations and piloted moving base simulator evaluations were conducted for manual control of pitch attitude, flight path, and airspeed for the approach and landing of a powered lift jet STOL aircraft. Flight path and speed response characteristics were described analytically and were evaluated for the simulation experiments which were carried out on a large motion simulator. The response characteristics were selected and evaluated for a specified path and speed control technique. These charcteristics were: (1) the initial pitch response and steady pitch rate sensitivity for control of attitude with a pitch rate command/ attitude hold system, (2) the initial flight path response, flight path overshoot, and flight path-airspeed coupling in response to a change in thrust, and (3) the sensitivity of airspeed to pitch attitude changes. Results are presented in the form of pilot opinion ratings and commentary, substantiated where appropriate by response time histories and aircraft states at the point of touchdown.

  8. Resistance ability evaluation of safety-related structures for the simulated aircraft accident

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Jin; Kim, Sung Woon; Choi, Jang Kyu [Daewoo E and C Co., Ltd., Suwon (Korea, Republic of)] (and others)

    2003-03-15

    Aircraft accidents on nuclear safety-related structures can cause severe damage to the safety of NPP(Nuclear Power Plant)s. To assess the safety of nuclear safety-related structures, the local damage and the dynamic response of global structures should be investigated together. This study have compared several local damage assessment formulas suggested for aircraft as an impactor, and have set the assessment system of local damage for impact-proof design of NPP containment buildings. And the local damage of nuclear safety-related structures in operation in Korea for commercial aircraft as impactor have been estimated. Impact load-time functions of the aircraft crash have been decided to assessment the safety of nuclear safety-related structures against the intentional colliding of commercial aircraft. Boeing 747 and Boeing 767 is selected as target aircraft based on the operation frequencies and weights. Comparison of the fire analysis methods showed that the method considering heat convection and radiation is adequate for the temperature analysis of the aircraft fuel fire. Finally, the study covered the analysis of the major structural drawings and design drawings with which three-dimensional finite element model analysis is expected to be performed.

  9. 76 FR 68675 - Revisions to the Export Administration Regulations (EAR): Control of Aircraft and Related Items...

    Science.gov (United States)

    2011-11-07

    ... Administration Regulations (EAR): Control of Aircraft and Related Items the President Determines No Longer... Portal: http://www.regulations.gov . The identification number for this rulemaking is BIS-2011-0033. By...

  10. A Hamiltonian Approach to Fault Isolation in a Planar Vertical Take–Off and Landing Aircraft Model

    Directory of Open Access Journals (Sweden)

    Rodriguez-Alfaro Luis H.

    2015-03-01

    Full Text Available The problem of fault detection and isolation in a class of nonlinear systems having a Hamiltonian representation is considered. In particular, a model of a planar vertical take-off and landing aircraft with sensor and actuator faults is studied. A Hamiltonian representation is derived from an Euler-Lagrange representation of the system model considered. In this form, nonlinear decoupling is applied in order to obtain subsystems with (as much as possible specific fault sensitivity properties. The resulting decoupled subsystem is represented as a Hamiltonian system and observer-based residual generators are designed. The results are presented through simulations to show the effectiveness of the proposed approach.

  11. The land use and land cover change database and its relative studies in China

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In the mid-1990s, we established the national operative dynamic information serving systems on natural resources and environment. During building the land-use/land-cover change (LUCC)database for the mid-1990s, 520 scenes of remotely sensed images of Landsat Thematic Mapper (TM) were interpreted into land-use/land-cover categories at scale of 1:100,000 under overall digital software environment after being geo-referenced and ortho-rectified. The vector map of land-use/land-cover in China at the scale of 1:100,000 was recently converted into a 1-km raster database that captures all ofthe high-resolution land-use information by calculating area percentage for each kind of land use category within every cell. Being designed as an operative dynamic information serving system,monitoring the change in land-use/land-cover at national level was executed. We have completed the updating of LUCC database by comparing the TM data in the mid-1990s with new data sources received during 1999-2000 and 1989-1990. The LUCC database has supported greatly the national LUCC research program in China and some relative studies are incompletely reviewed in this paper.

  12. Determining Land Surface Temperature Relations with Land Use-Land Cover and Air Pollution

    Science.gov (United States)

    Kahya, Ceyhan; Bektas Balcik, Filiz; Burak Oztaner, Yasar; Guney, Burcu

    2016-04-01

    Rapid population growth in conjunction with unplanned urbanization, expansion, and encroachment into the limited agricultural fields and green areas have negative impacts on vegetated areas. Land Surface Temperature (LST), Urban Heat Islands (UHI) and air pollution are the most important environmental problems that the extensive part of the world suffers from. The main objective of this research is to investigate the relationship between LST, air pollution and Land Use-Land Cover (LULC) in Istanbul, using Landsat 8 OLI satellite image. Mono-window algorithm is used to compute LST from Landsat 8 TIR data. In order to determine the air pollution, in-situ measurements of particulate matter (PM10) of the same day as the Landsat 8 OLI satellite image are obtained. The results of this data are interpolated using the Inverse Distance Weighted (IDW) method and LULC categories of Istanbul were determined by using remote sensing indices. Error matrix was created for accuracy assessment. The relationship between LST, air pollution and LULC categories are determined by using regression analysis method. Keywords: Land Surface Temperature (LST), air pollution, Land Use-Land Cover (LULC), Istanbul

  13. Evaluation of V/STOL research aircraft design. [landing approaches, propulsion/control, piloted moving base simulator

    Science.gov (United States)

    Deckert, W. H.; Holzhauser, C. A.

    1973-01-01

    The evaluation and evolution of direct jet lift V/STOL transport aircraft designs are discussed. The V/STOL transport design selected as an example is a lift-fan design that was evaluated as a candidate configuration for a possible future V/STOL research transport. The paper includes discussion of potential advanced V/STOL landing approach profiles as key design requirements for V/STOL aircraft, description and experimental results of an integrated propulsion/control system designed to achieve desired advanced V/STOL near-terminal operating capabilities, and results from evaluating V/STOL designs on piloted moving-base simulators. This paper discusses use of the piloted moving-base simulator as a design tool for evolving satisfactory V/STOL stabilization and propulsion/control systems. Included are problems and solutions identified during simulation of simultaneous decelerating/descent steep curved landing approaches under instrument flight conditions. Simulation results are also compared to flight results obtained with the DO-31 V/STOL research transport.

  14. Application of the concept of dynamic trim control and nonlinear system inverses to automatic control of a vertical attitude takeoff and landing aircraft

    Science.gov (United States)

    Smith, G. A.; Meyer, G.

    1981-01-01

    A full envelope automatic flight control system based on nonlinear inverse systems concepts has been applied to a vertical attitude takeoff and landing (VATOL) fighter aircraft. A new method for using an airborne digital aircraft model to perform the inversion of a nonlinear aircraft model is presented together with the results of a simulation study of the nonlinear inverse system concept for the vertical-attitude hover mode. The system response to maneuver commands in the vertical attitude was found to be excellent; and recovery from large initial offsets and large disturbances was found to be very satisfactory.

  15. Application of the concept of dynamic trim control and nonlinear system inverses to automatic control of a vertical attitude takeoff and landing aircraft

    Science.gov (United States)

    Smith, G. A.; Meyer, G.

    1981-01-01

    A full envelope automatic flight control system based on nonlinear inverse systems concepts has been applied to a vertical attitude takeoff and landing (VATOL) fighter aircraft. A new method for using an airborne digital aircraft model to perform the inversion of a nonlinear aircraft model is presented together with the results of a simulation study of the nonlinear inverse system concept for the vertical-attitude hover mode. The system response to maneuver commands in the vertical attitude was found to be excellent; and recovery from large initial offsets and large disturbances was found to be very satisfactory.

  16. Annual view (1999) - aeronautic relation/space relation. Aeronautic relation - special aircraft; Nenkan tenbo (1999) koku kankei uchu kankei. Tokushu kokuki kanren

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-03-05

    The military use tilt rotor entered the practical use stage, and in May the first plane of quantity model MV-22B was delivered to the U.S. Marine Corps. As to the private use BA609, the development is being proceeded with, jointly with Kawasaki Heavy Industries which also joined the development, and that is planned to be completed in 2000. Relating to the unmanned aircraft, in Japan, Fuji Heavy Industries has completed aircraft with jet engine for experiment on soft landing under the lunar probe orbitary satellite plan worked on by National Space Development Agency of Japan and the Institute of the Space and Astronautical Science. The flight test is planned to be conducted in 2000. At National Aerospace Laboratory, Science and Technology Agency, non-powered unmanned supersonic experimental transport is planned, and the flight test is expected to be made in FY 2002. At NASA of the U.S., a prototype made a flight in August of the unmanned flying wing which flies at a high altitude for a long time by solar cells and fuel cells. The airship is now reviewed in the light of the environmental problem. National Aerospace Laboratory, Science and Technology Agency has started the R and S of an unmanned airship aimed at stationarily staying in the stratosphere using solar cells and fuel cells. (NEDO)

  17. Commercial Aircraft Maintenance Experience Relating to Engine External Hardware

    Science.gov (United States)

    Soditus, Sharon M.

    2006-01-01

    Airlines are extremely sensitive to the amount of dollars spent on maintaining the external engine hardware in the field. Analysis reveals that many problems revolve around a central issue, reliability. Fuel and oil leakage due to seal failure and electrical fault messages due to wire harness failures play a major role in aircraft delays and cancellations (D&C's) and scheduled maintenance. Correcting these items on the line requires a large investment of engineering resources and manpower after the fact. The smartest and most cost effective philosophy is to build the best hardware the first time. The only way to do that is to completely understand and model the operating environment, study the field experience of similar designs and to perform extensive testing.

  18. Optimisation of shimmy suppression device in an aircraft main landing gear

    Science.gov (United States)

    Li, Yuan; Jiang, Jason Zheng; Neild, Simon

    2016-09-01

    In earlier publications of landing gear shimmy analysis, efforts have concentrated on predicting the onset of shimmy instability and investigating how to stabilise shimmy-prone landing gears. Less attention has been given to the improvements of shimmy performance for a gear that is free from dynamic instability. This is the main interest of this work. We investigate the effectiveness of a linear passive mechanical device that consists of springs, dampers and inerters on suppressing landing gear shimmy oscillations. A linear model of a Fokker 100 main landing gear and two configurations of candidate shimmy suppression device have been presented. Considering the physical shimmy motions, time-domain optimisation of the parameters in the shimmy suppression devices, using a cost function of maximum amplitude of gear torsional-yaw motion, has been carried out. The performance advantage of a shimmy suppression device incorporating inerter has been presented.

  19. Future land-use related water demand in California

    Science.gov (United States)

    Wilson, Tamara; Sleeter, Benjamin M.; Cameron, D. Richard

    2016-01-01

    Water shortages in California are a growing concern amidst ongoing drought, earlier spring snowmelt, projected future climate warming, and currently mandated water use restrictions. Increases in population and land use in coming decades will place additional pressure on already limited available water supplies. We used a state-and-transition simulation model to project future changes in developed (municipal and industrial) and agricultural land use to estimate associated water use demand from 2012 to 2062. Under current efficiency rates, total water use was projected to increase 1.8 billion cubic meters(+4.1%) driven primarily by urbanization and shifts to more water intensive crops. Only if currently mandated 25% reductions in municipal water use are continuously implemented would water demand in 2062 balance to water use levels in 2012. This is the first modeling effort of its kind to examine regional land-use related water demand incorporating historical trends of both developed and agricultural land uses.

  20. Future land-use related water demand in California

    Science.gov (United States)

    Wilson, Tamara S.; Sleeter, Benjamin M.; Cameron, D. Richard

    2016-05-01

    Water shortages in California are a growing concern amidst ongoing drought, earlier spring snowmelt, projected future climate warming, and currently mandated water use restrictions. Increases in population and land use in coming decades will place additional pressure on already limited available water supplies. We used a state-and-transition simulation model to project future changes in developed (municipal and industrial) and agricultural land use to estimate associated water use demand from 2012 to 2062. Under current efficiency rates, total water use was projected to increase 1.8 billion cubic meters (+4.1%) driven primarily by urbanization and shifts to more water intensive crops. Only if currently mandated 25% reductions in municipal water use are continuously implemented would water demand in 2062 balance to water use levels in 2012. This is the first modeling effort of its kind to examine regional land-use related water demand incorporating historical trends of both developed and agricultural land uses.

  1. FEA Based Analysis of Composite Torque Link for a Passenger Aircraft Landing Gear

    Directory of Open Access Journals (Sweden)

    R. Arravind

    2013-08-01

    Full Text Available In the implementation of a composite landing gear technology program was started, a composite torque link for transport airplane landing gear applications was developed. The torque link was designed by finite element analysis and analysis for maximum stress condition. The torque link was fabricated by Resin Transfer Moulding (RTM for which a tooling concept was developed. Static tests demonstrated the load carrying capabilities in undamaged and damaged condition of the torque link since all specimens failed beyond their Design Ultimate Load level for that case we are hereby carryout the analysis process in order to find the ultimate load and yield stress for the torque link.

  2. The Investigation of Take-off and Landing Characteristics of Jet Shortened Take-off and Landing Aircraft (STOL) (K Voprosu Issledovaniya Vzletno-Posadochnykh Kharakteristik Reaktivnykh Samoletov Ukorochennogo Vzleta i Posadki (SUVP)),

    Science.gov (United States)

    1977-07-25

    including an analysis made from the viewpoint of take-off and landing and flight characteristics , as well as safety and economy is vital for this purpose...No. 16, l96~ . 8. A Manual on VTOL Aircraft. Trudy TsAGI , 1965. 9. W. Seibold. Untersuchungen uber die von Hubstrahlen an Senkrechstartern Erzeugen

  3. Terminal area automatic navigation, guidance, and control research using the Microwave Landing System (MLS). Part 2: RNAV/MLS transition problems for aircraft

    Science.gov (United States)

    Pines, S.

    1982-01-01

    The problems in navigation and guidance encountered by aircraft in the initial transition period in changing from distance measuring equipment, VORTAC, and barometric instruments to the more precise microwave landing system data type navaids in the terminal area are investigated. The effects of the resulting discontinuities on the estimates of position and velocity for both optimal (Kalman type navigation schemes) and fixed gain (complementary type) navigation filters, and the effects of the errors in cross track, track angle, and altitude on the guidance equation and control commands during the critical landing phase are discussed. A method is presented to remove the discontinuities from the navigation loop and to reconstruct an RNAV path designed to land the aircraft with minimal turns and altitude changes.

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

    Science.gov (United States)

    Loeb, M.; Moran, S. V.

    1977-01-01

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

  5. Airport operator and aircraft operator in case of bird strike. Relations, obligations and liability

    Directory of Open Access Journals (Sweden)

    Sylwia KACZYŃSKA-ADAMCZYK

    2011-01-01

    Full Text Available Air transport is subject to various risks. One of them is bird strike hazard. Despite numerous regulations concerning prevention from this type of occurrence, it is not possible to eliminate them entirely.Bird strikes most often take place during take-off and landing, that is on or in the vicinity of an airport. For that reason airport operators are the first parties that can be made accountable for this occurence. International law imposes numerous responsibilities on airport operators in terms of bird strike hazard prevention on air operations, thus placing airport operators in a “key position” in the system of safety. However, the party that suffers significant damages in the first instance, is the aircraft operator. If a bird strike takes place on or in the vicinity of an airport, an aicraft operator can sue the airport operator for compensation of damages. Generally, the issue of indemnity is subject to out of court negotiations, however instances in which there is a lack of agreement between the parties, i.e. airport operator, aircraft operator or their insurers, lead to legal proceedings for compensation.This article attempts to illustrate the relationship between air traffic participants such as airport operators and aircraft operators in connection with their obligations and liability, particulary taking into account the legal obligations of an airport operator.

  6. Definitions of Terms Relating to Aircraft Windscreens, Canopies, and Transparencies

    Science.gov (United States)

    1993-03-01

    Related Subjects. Pergamon Press Ltd, 1973. 11. A.M. Wittfoht and Carl Hanser. Plastics Technical Dictionary. Verlag, Munchen, 1956. 12. J.A. Wordingham and P. Reboul . Dictionary of Plastics. George Newnes Ltd., London, 1964. 40

  7. The design, development, and flight test results of the Boeing 737 aircraft antennas for the ICAO demonstration of the TRSB microwave landing system

    Science.gov (United States)

    Campbell, T. G.; White, W. E.; Gilreath, M. C.

    1976-01-01

    The Research Support Flight System, a modified Boeing 737, was used to evaluate the performance of several aircraft antennas and locations for the Time Reference Scanning Beam (TRSB) Microwave Landing System (MLS). These tests were conducted at the National Aviation Facilities Experimental Center (NAFEC), Atlantic City, New Jersey on December 18, 1975. The flight tests measured the signal strength and all pertinent MLS data during a straight-in approach, a racetrack approach, and ICAO approach profiles using the independent antenna-receiver combinations simultaneously on the aircraft. Signal drop-outs were experienced during the various approaches but only a small percentage could be attributed to antenna pattern effects.

  8. Overview of Terrain Relative Navigation Approaches for Precise Lunar Landing

    Science.gov (United States)

    Johnson, Andrew E.; Montgomery, James F.

    2008-01-01

    The driving precision landing requirement for the Autonomous Landing and Hazard Avoidance Technology project is to autonomously land within 100m of a predetermined location on the lunar surface. Traditional lunar landing approaches based on inertial sensing do not have the navigational precision to meet this requirement. The purpose of Terrain Relative Navigation (TRN) is to augment inertial navigation by providing position or bearing measurements relative to known surface landmarks. From these measurements, the navigational precision can be reduced to a level that meets the 100m requirement. There are three different TRN functions: global position estimation, local position estimation and velocity estimation. These functions can be achieved with active range sensing or passive imaging. This paper gives a survey of many TRN approaches and then presents some high fidelity simulation results for contour matching and area correlation approaches to TRN using active sensors. Since TRN requires an a-priori reference map, the paper concludes by describing past and future lunar imaging and digital elevation map data sets available for this purpose.

  9. Preliminary performance of a vertical-attitude takeoff and landing, supersonic cruise aircraft concept having thrust vectoring integrated into the flight control system

    Science.gov (United States)

    Robins, A. W.; Beissner, F. L., Jr.; Domack, C. S.; Swanson, E. E.

    1985-01-01

    A performance study was made of a vertical attitude takeoff and landing (VATOL), supersonic cruise aircraft concept having thrust vectoring integrated into the flight control system. Those characteristics considered were aerodynamics, weight, balance, and performance. Preliminary results indicate that high levels of supersonic aerodynamic performance can be achieved. Further, with the assumption of an advanced (1985 technology readiness) low bypass ratio turbofan engine and advanced structures, excellent mission performance capability is indicated.

  10. Relating a Jet-Surface Interaction Experiment to a Commercial Supersonic Transport Aircraft Using Numerical Simulations

    Science.gov (United States)

    Dippold, Vance F. III; Friedlander, David

    2017-01-01

    Reynolds-Averaged Navier-Stokes (RANS) simulations were performed for a commercial supersonic transport aircraft concept and experimental hardware models designed to represent the installed propulsion system of the conceptual aircraft in an upcoming test campaign. The purpose of the experiment is to determine the effects of jet-surface interactions from supersonic aircraft on airport community noise. RANS simulations of the commercial supersonic transport aircraft concept were performed to relate the representative experimental hardware to the actual aircraft. RANS screening simulations were performed on the proposed test hardware to verify that it would be free from potential rig noise and to predict the aerodynamic forces on the model hardware to assist with structural design. The simulations showed a large region of separated flow formed in a junction region of one of the experimental configurations. This was dissimilar with simulations of the aircraft and could invalidate the noise measurements. This configuration was modified and a subsequent RANS simulation showed that the size of the flow separation was greatly reduced. The aerodynamic forces found on the experimental models were found to be relatively small when compared to the expected loads from the model’s own weight.Reynolds-Averaged Navier-Stokes (RANS) simulations were completed for two configurations of a three-stream inverted velocity profile (IVP) nozzle and a baseline single-stream round nozzle (mixed-flow equivalent conditions). For the Sideline and Cutback flow conditions, while the IVP nozzles did not reduce the peak turbulent kinetic energy on the lower side of the jet plume, the IVP nozzles did significantly reduce the size of the region of peak turbulent kinetic energy when compared to the jet plume of the baseline nozzle cases. The IVP nozzle at Sideline conditions did suffer a region of separated flow from the inner stream nozzle splitter that did produce an intense, but small, region of

  11. Field-of-View Requirements for Approach and Landing of V/STOL (Vertical/Short Take-Off and Landing) Aircraft.

    Science.gov (United States)

    1978-08-01

    orthogonal) coordinate of a point of regard in the field of view defined with respect to the point where the aircraft longitudinal body reference...and 1i except that the origin of FOVi , FOVui in the picture plane is where the aircraft longitudinal body reference axis inter- cepts the picture

  12. Relative Efficiency of Surface Energy Budgets Over Different Land Covers

    Science.gov (United States)

    Yang, Jiachuan

    The partitioning of available solar energy into different fluxes at the Earth's surface is important in determining different physical processes, such as turbulent transport, subsurface hydrology, land-atmospheric interactions, etc. Direct measurements of these turbulent fluxes were carried out using eddy-covariance (EC) towers. However, the distribution of EC towers is sparse due to relatively high cost and practical difficulties in logistics and deployment. As a result, data is temporally and spatially limited and is inadequate to be used for researches at large scales, such as regional and global climate modeling. Besides field measurements, an alternative way is to estimate turbulent fluxes based on the intrinsic relations between surface energy budget components, largely through thermodynamic equilibrium. These relations, referred as relative efficiency, have been included in several models to estimate the magnitude of turbulent fluxes in surface energy budgets such as latent heat and sensible heat. In this study, three theoretical models based on the lumped heat transfer model, the linear stability analysis and the maximum entropy principle respectively, were investigated. Model predictions of relative efficiencies were compared with turbulent flux data over different land covers, viz. lake, grassland and suburban surfaces. Similar results were observed over lake and suburban surface but significant deviation is found over vegetation surface. The relative efficiency of outgoing longwave radiation is found to be orders of magnitude deviated from theoretic predictions. Meanwhile, results show that energy partitioning process is influenced by the surface water availability to a great extent. The study provides insight into what property is determining energy partitioning process over different land covers and gives suggestion for future models.

  13. 舰载机前轮滑跃起飞技术%Carriered-Aircraft Taking-off with Nose Landing Gear on Ski-jump Ramp Profile

    Institute of Scientific and Technical Information of China (English)

    房兴波; 聂宏; 于浩

    2011-01-01

    The ramp profile is introduced to the aircraft carrier to make it sure that the nose landing gear goes to the ramp profile after the catapult process, so that the nose of the aircraft rise. The simplified model of the whole carriered-aircraft during the process of catapult take off is built. Dynamic equations about catapult run phase are presented. The dynamic response of the carriered-aircraft during the process of catapult take off is calculated via Runge-Kutta procedure. The results indicate that the introduction of ramp profile can decrease the flight path sinkage during the catapult take off, the off-carrier velocity of the aircraft, and increase the take off masses and the load of the nose landing-gear.%在航母甲板上引入斜坡跑道,使舰载机弹射冲程结束后,前轮单独进入斜坡跑道,从而使飞机抬头.建立了舰载机起飞时的简化分析模型,给出了基于该分析模型的运动微分方程及相关参数的表达式,并采用龙格库塔算法对舰载执在斜坡跑道上滑跑起飞速一过程的动态响应进行了数值仿真.仿真结果表明,斜坡跑道的引入可以明显降低舰载机离舰后航迹的下沉量,降低舰载机的离舰速度,增加起飞质量,增大前起落架载荷.

  14. Aircraft engine exhaust emissions and other airport-related contributions to ambient air pollution: A review

    Science.gov (United States)

    Masiol, Mauro; Harrison, Roy M.

    2014-10-01

    Civil aviation is fast-growing (about +5% every year), mainly driven by the developing economies and globalisation. Its impact on the environment is heavily debated, particularly in relation to climate forcing attributed to emissions at cruising altitudes and the noise and the deterioration of air quality at ground-level due to airport operations. This latter environmental issue is of particular interest to the scientific community and policymakers, especially in relation to the breach of limit and target values for many air pollutants, mainly nitrogen oxides and particulate matter, near the busiest airports and the resulting consequences for public health. Despite the increased attention given to aircraft emissions at ground-level and air pollution in the vicinity of airports, many research gaps remain. Sources relevant to air quality include not only engine exhaust and non-exhaust emissions from aircraft, but also emissions from the units providing power to the aircraft on the ground, the traffic due to the airport ground service, maintenance work, heating facilities, fugitive vapours from refuelling operations, kitchens and restaurants for passengers and operators, intermodal transportation systems, and road traffic for transporting people and goods in and out to the airport. Many of these sources have received inadequate attention, despite their high potential for impact on air quality. This review aims to summarise the state-of-the-art research on aircraft and airport emissions and attempts to synthesise the results of studies that have addressed this issue. It also aims to describe the key characteristics of pollution, the impacts upon global and local air quality and to address the future potential of research by highlighting research needs.

  15. Aircraft Operations Classification System

    Science.gov (United States)

    Harlow, Charles; Zhu, Weihong

    2001-01-01

    Accurate data is important in the aviation planning process. In this project we consider systems for measuring aircraft activity at airports. This would include determining the type of aircraft such as jet, helicopter, single engine, and multiengine propeller. Some of the issues involved in deploying technologies for monitoring aircraft operations are cost, reliability, and accuracy. In addition, the system must be field portable and acceptable at airports. A comparison of technologies was conducted and it was decided that an aircraft monitoring system should be based upon acoustic technology. A multimedia relational database was established for the study. The information contained in the database consists of airport information, runway information, acoustic records, photographic records, a description of the event (takeoff, landing), aircraft type, and environmental information. We extracted features from the time signal and the frequency content of the signal. A multi-layer feed-forward neural network was chosen as the classifier. Training and testing results were obtained. We were able to obtain classification results of over 90 percent for training and testing for takeoff events.

  16. Understanding decreases in land relative humidity with global warming: conceptual model and GCM simulations

    CERN Document Server

    Byrne, Michael P

    2016-01-01

    Climate models simulate a strong land-ocean contrast in the response of near-surface relative humidity to global warming: relative humidity tends to increase slightly over oceans but decrease substantially over land. Surface energy balance arguments have been used to understand the response over ocean but are difficult to apply over more complex land surfaces. Here, a conceptual box model is introduced, involving moisture transport between the land and ocean boundary layers and evapotranspiration, to investigate the decreases in land relative humidity as the climate warms. The box model is applied to idealized and full-complexity (CMIP5) general circulation model simulations, and it is found to capture many of the features of the simulated changes in land relative humidity. The box model suggests there is a strong link between fractional changes in specific humidity over land and ocean, and the greater warming over land than ocean then implies a decrease in land relative humidity. Evapotranspiration is of sec...

  17. Dynamics and Test Method of Carrier-based Aircraft Nose Landing Gear Sudden Extension%舰载机前起落架突伸动力学分析及试验方法

    Institute of Scientific and Technical Information of China (English)

    魏小辉; 刘成龙; 聂宏; 张明; 尹乔之

    2013-01-01

    为了了解舰载机前起落架突伸试验与实际突伸过程的当量关系,本文以某舰载机为研究对象,建立了全机弹射起飞动力学模型,进行了全机弹射起飞动力学分析,得到了前起落架突伸过程中的动态响应.提出了基于当量质量的前起落架突伸动力学试验方法,设计了试验方案,建立了前起落架突伸动力学试验分析模型,进行了突伸动力学分析.进而依据全机突伸动力学分析结果,对基于当量质量的前起落架突伸动力学试验中相关参数的选取进行了探讨研究,结果表明:当突伸当量质量系数取0.8时,突伸动力学响应特性与全机弹射起飞突伸过程的动态响应结果比较吻合.%In order to understand the equivalent relationship of a landing gear's sudden-extension test and the real suddenextension process of a carrier-based aircraft,a dynamics model of a certain carrier-based aircraft catapult-assisted takeoff process is established.The catapult-assisted takeoff dynamics is simulated and the nose landing gears dynamic response to the sudden-extension process is obtained.A test method is introduced to study the nose landing gear 's sudden extension based on equivalent mass.Accordingly,a test program is presented for independent nose landing gear sudden-extension analysis.With simulated results of the models introduced above,the value range of relevant test parameters is studied.It is shown that the independent nose landing gear sudden-extension dynamic response is relatively consistent with the full-aircraft catapult-assisted takeoff dynamics when the equivalent mass coefficient is equal to 0.8.

  18. A new Methane and carbon dioxide eddy-covariance flux monitor for land-based, sea-based, and aircraft-based applications.

    Science.gov (United States)

    Crosson, Eric; Karion, Anna; Law, Beverly; Sweeney, Colm; Christoph, Thomas; Rahn, Thomas; Mc Gillis, Wade

    2010-05-01

    It is now recognized that a comprehensive understanding of global warming's full impact on local and global weather patterns still requires much more data, namely, mapping the atmospheric mixing ratios (concentrations) of carbon dioxide (CO2), methane (CH4). Moreover, even as this understanding becomes more complete, there will also be a major ongoing need to continuously map quantitative levels of these gases to monitor the effects of regional, national and international green house gas (GHG) reduction efforts, as well as to certify compliance. To carry out this effort will require analyzers that can produce continuous, parts-per-billion precision, high accuracy measurements of ambient levels of atmospheric gases at very high data rates over years of operation in land-based, sea-based, as well as aircraft-based applications. A challenge worth considering is to create a single analyzer that can address the GHG measurement needs of virtually all these applications. Such an analyzer would be required to produce slow time-response (e.g. minute to minute data is considered very fast time response), and very high accuracy (which can also be described as precision across a network of independent measurements) as required for atmospheric inversions and some mobile applications as well as fast time-response (e.g. 1 Hz to 10 Hz) and excellent relative precision (without the need for long-term accuracy, or comparability of mixing ratios across multiple sites) as needed for eddy covariance flux measurements. Such an analyzer would give the research community much more flexibility, a wider choice of research applications, reduce overall capital equipment cost, and improve the inter-comparability of GHG measurements across applications. Picarro, Inc. has developed a high speed Cavity Ring-Down Spectroscopy (CRDS) based analyzer, able to measure carbon dioxide (CO2) concentration to a precision (one standard deviation) of 200 parts-per-billion (ppbv), and methane (CH4

  19. An investigation into the vertical axis control power requirements for landing VTOL type aircraft onboard nonaviation ships in various sea states

    Science.gov (United States)

    Stevens, M. E.; Roskam, J.

    1985-01-01

    The problem of determining the vertical axis control requirements for landing a VTOL aircraft on a moving ship deck in various sea states is examined. Both a fixed-base piloted simulation and a nonpiloted simulation were used to determine the landing performance as influenced by thrust-to-weight ratio, vertical damping, and engine lags. The piloted simulation was run using a fixed-based simulator at Ames Research center. Simplified versions of an existing AV-8A Harrier model and an existing head-up display format were used. The ship model used was that of a DD963 class destroyer. Simplified linear models of the pilot, aircraft, ship motion, and ship air-wake turbulence were developed for the nonpiloted simulation. A unique aspect of the nonpiloted simulation was the development of a model of the piloting strategy used for shipboard landing. This model was refined during the piloted simulation until it provided a reasonably good representation of observed pilot behavior.

  20. 六旋翼飞行器平稳着陆方法研究%Safe Landing Method Study of Six Rotor Aircraft

    Institute of Scientific and Technical Information of China (English)

    崔凤利; 杨立志

    2014-01-01

    MWC-2012 Six rotor aircraft uses air pressure to measure its height.In the low lands,barometer has lots of measurement errors,resulting in frequent crashes.In order to overcome this phenomenon,this paper uses the ultrasonic ranging module in stead of barometer for aircraft landing height measurement.The experi-ment shows that the landing judgment on the basis of ultrasonic ranging can effectively prevent the air crash.%MWC-2012六旋翼飞行器采用气压计进行高度检测,在低空着陆时,气压计测量误差很大,造成频繁摔机。为了克服这种现象,本文采用超声测距模块替代气压计实现飞行器着陆前的高度判定,实践表明,依据超声测距进行着陆判断,能够有效防止摔机现象。

  1. Analysis of the Relative Sustainability of Land Devoted to Bioenergy: Comparing Land-Use Alternatives in China

    Directory of Open Access Journals (Sweden)

    Jiashun Huang

    2017-05-01

    Full Text Available When developing land to meet various human needs, conducting assessments of different alternatives regarding their sustainability is critical. Among different alternatives of land-use, devoting land to bioenergy is relatively novel, in high demand, and important for addressing the energy crisis and mitigating carbon emissions. Furthermore, the competition and disputes among limited land-use for bioenergy and the combination of food production and housing are tense. Thus, which alternative of land-use is more sustainable is an important question, yet it is still under-investigated. The main purposes of this study are to investigate the merits and problems of land-use for bioenergy and to compare the relative sustainability of land-use for bioenergy, food production, and housing based on habitants’ perceptions. Multi-criteria analysis is applied to the case study in the context of China, evaluating multiple criteria in economic, environmental, and social dimensions. Therefore, this study presents a comprehensive assessment of different scenarios of land-use designed to be implemented and some implications for optimum land-use policies.

  2. Automation of reverse engineering process in aircraft modeling and related optimization problems

    Science.gov (United States)

    Li, W.; Swetits, J.

    1994-01-01

    During the year of 1994, the engineering problems in aircraft modeling were studied. The initial concern was to obtain a surface model with desirable geometric characteristics. Much of the effort during the first half of the year was to find an efficient way of solving a computationally difficult optimization model. Since the smoothing technique in the proposal 'Surface Modeling and Optimization Studies of Aerodynamic Configurations' requires solutions of a sequence of large-scale quadratic programming problems, it is important to design algorithms that can solve each quadratic program in a few interactions. This research led to three papers by Dr. W. Li, which were submitted to SIAM Journal on Optimization and Mathematical Programming. Two of these papers have been accepted for publication. Even though significant progress has been made during this phase of research and computation times was reduced from 30 min. to 2 min. for a sample problem, it was not good enough for on-line processing of digitized data points. After discussion with Dr. Robert E. Smith Jr., it was decided not to enforce shape constraints in order in order to simplify the model. As a consequence, P. Dierckx's nonparametric spline fitting approach was adopted, where one has only one control parameter for the fitting process - the error tolerance. At the same time the surface modeling software developed by Imageware was tested. Research indicated a substantially improved fitting of digitalized data points can be achieved if a proper parameterization of the spline surface is chosen. A winning strategy is to incorporate Dierckx's surface fitting with a natural parameterization for aircraft parts. The report consists of 4 chapters. Chapter 1 provides an overview of reverse engineering related to aircraft modeling and some preliminary findings of the effort in the second half of the year. Chapters 2-4 are the research results by Dr. W. Li on penalty functions and conjugate gradient methods for

  3. Application of MBSE Method During Landing Gear System Design for Civil Aircraft%MBSE在民机起落架系统设计中的应用

    Institute of Scientific and Technical Information of China (English)

    汤超; 方俊伟; 谢陵; 张磊; 夏语冰

    2015-01-01

    This paper clearly introduces function analysis process and method of large-scale civil aircraft based on Raphsody, and its implementation in landing gear system design. Usecase, function flow, sequence and executable state machine of syetem are set up by model. toguide the requirement analysis, function analysis and architecture design of highly complex system in large-scale civil aircraft, and to explore practice of MBSE in highly complex system of civil aircraft.%详细介绍基于Raphsody的大型民机系统功能开发流程与方法,及其在民用飞机起落架系统设计中的应用。通过模型的方式对系统建立用例、功能流、时序关系和可用于执行验证的状态机来描述系统,指导大型民机复杂系统设计过程中的需求分析、功能分析和设计综合工作,探索MBSE方法在民机复杂系统设计中的指导作用。

  4. The Pilot Land Data System (PLDS) at the Ames Research Center manages aircraft data in collaboration with an ecosystem research project

    Science.gov (United States)

    Angelici, Gary; Popovici, Lidia; Skiles, Jay

    1991-01-01

    The Pilot Land Data System (PLDS) is a data and information system serving NASA-supported investigators in the land science community. The three nodes of the PLDS, one each at the Ames Research Center (ARC), the Goddard Space Flight Center (GSFC) and the Jet Propulsion Laboratory (JPL), cooperate in providing consistent information describing the various data holding in the hardware and software (accessible via network and modem) that provide information about and access to PLDS-held data, which is available for distribution. A major new activity of the PLDS node at the Ames Research Center involves the interaction of the PLDS with an active NASA ecosystem science project, the Oregon Transect Ecosystems Research involves the management of, access to, and distribution of the large volume of widely-varying aircraft data collected by OTTER. The OTTER project, is managed by researchers at the Ames Research Center and Oregon State University. Its principal objective is to estimate major fluxes of carbon, nitrogen, and water of forest ecosystems using an ecosystem process model driven by remote sensing data. Ten researchers at NASA centers and universities are analyzing data for six sites along a temperature-moisture gradient across the western half of central Oregon (called the Oregon Transect). Sensors mounted on six different aircraft have acquired data over the Oregon Transect in support of the OTTER project.

  5. FEATURES OF INNOVATIVE MANAGEMENT OF REFORMATORY CHANGES IN SYSTEM OF THE LAND RELATIONS

    Directory of Open Access Journals (Sweden)

    Tatyana ZAVOLICHNA

    2017-06-01

    Full Text Available In the article the authors investigated the state of land reform in Ukraine evaluated the prospects of its development following on from the experience of Bulgaria, Romania and Hungary. An innovative algorithm of change management in the system of administration of land relations was suggested, which role is to provide opportunities to expeditiously manage land conversion, effectively overcome resistance to change.

  6. Understanding Decreases in Land Relative Humidity with Global Warming: Conceptual Model and GCM Simulations

    Science.gov (United States)

    Byrne, Michael P.; O'Gorman, Paul A.

    2016-12-01

    Climate models simulate a strong land-ocean contrast in the response of near-surface relative humidity to global warming: relative humidity tends to increase slightly over oceans but decrease substantially over land. Surface energy balance arguments have been used to understand the response over ocean but are difficult to apply over more complex land surfaces. Here, a conceptual box model is introduced, involving moisture transport between the land and ocean boundary layers and evapotranspiration, to investigate the decreases in land relative humidity as the climate warms. The box model is applied to idealized and full-complexity (CMIP5) general circulation model simulations, and it is found to capture many of the features of the simulated changes in land relative humidity. The box model suggests there is a strong link between fractional changes in specific humidity over land and ocean, and the greater warming over land than ocean then implies a decrease in land relative humidity. Evapotranspiration is of secondary importance for the increase in specific humidity over land, but it matters more for the decrease in relative humidity. Further analysis shows there is a strong feedback between changes in surface-air temperature and relative humidity, and this can amplify the influence on relative humidity of factors such as stomatal conductance and soil moisture.

  7. Hierarchical Colored Timed Petri Nets for Maintenance Process Modeling of Civil Aircraft

    Institute of Scientific and Technical Information of China (English)

    FU Cheng-cheng; SUN You-chao; LU Zhong

    2008-01-01

    Civil aircraft maintenance process simulation model is an effective method for analyzing the maintainability of a civil aircraft. First, we present the Hierarchical Colored Timed Petri Nets for maintenance process modeling of civil aircraft. Then, we expound a general method of civil aircraft maintenance activities, determine the maintenance level for decomposition, and propose the methods of describing logic of relations between the maintenance activities based on Petri Net. Finally, a time Colored Petri multi-level network modeling and simulation procedures and steps are given with the maintenance example of the landing gear burst tire of a certain type of aircraft. The feasibility of the method is proved by the example.

  8. Land-related conflicts in Sub-Saharan Africa

    African Journals Online (AJOL)

    defined property rights and management plans have led to the over-exploitation .... The inability of governments to deliver on restitution claims has other unpleasant ... As there is no single definition of 'land' and property rights, there is also a.

  9. Flight system design for a receiver aircraft to perform autonomous aerial refueling provided with relative position data link

    Science.gov (United States)

    Awni, Kahtan A.

    An automatic aerial refueling system was developed that is capable of controlling the receiving aircraft to rendezvous, dock and station keep the receiver refueling probe in the tanker refueling probe. The automatic refueling system consisted of an active trajectory generator, a guidance system and a control system. The active trajectory generator continuously updated the commanded rendezvous trajectory to be flown by the receiver aircraft. This active trajectory generator concept incorporated design variables that the designer could use to specify the time sequence of the rendezvous and docking maneuver. The output of the trajectory generator was then the command to the flight systems guidance and control systems. To demonstrate this automatic aerial refueling system concept, a detailed design of the flight system algorithms was done for typical aerial refueling mission with a heavy jet tanker aircraft similar to the KC135 and the SIAI-Marchetti S-211 Jet Trainer as a receiver aircraft. The systems gains were selected to minimize the control surface activity while achieving adequate tracking. A simulation was developed that included the flight system algorithms, linear models of the receiver aircraft, atmospheric and tanker wake disturbance models. The performance of the aerial refueling system design was then evaluated in a batch computer simulator. The simulation study demonstrated results showed better disturbance rejection relative to the controller performance while minimizing the utilization of the control surfaces. Results also demonstrated the ability to schedule rendezvous.

  10. Tenure security, social relations and contract choice: Endogenous matching in the Chinese land rental market

    Science.gov (United States)

    Ma, Xianlei; Zhou, Yuepeng; Shi, Xiaoping

    2017-04-01

    In China, land rental transactions have increased considerably since the 1990s, but there exists a high degree of segmentation and informal features. The rental transactions between partners with close social relations and the use of informal contracts remain a common phenomenon in many regions, which strongly reduce the potential of the land rental market to enhance productivity and equity. The current literature postulates that the insecurity of land property rights may restrict land transactions between members of same social relations. Studies conducted in China show that the land rentals between partners with closer social relations prefer informal contracts because these contracts are self-enforced based on trust and reputation. However, little literature has jointly examined the effect of land tenure security and social relations on joint decisions of partner and contract choice in the Chinese land rental market. Based on household data collected in Jiangxi and Liaoning provinces in 2015, this paper aims to examine the relationship between land tenure security perceptions, social relation and land rental contract choices in China. We differentiate between formal and informal contracts of land rental activities because they have different enforcement mechanisms and thus different risk-sharing strategy. With regards to social relations, we differ among relatives, villagers living in the same village and strangers according to social distance. In order to reduce estimation bias without accounting for endogenous matching between landlords and tenants, we investigate the joint partner and contract choices in the land rental market using a nested logit framework. The paper contributes to the literature on the effect of tenure security and social relations on land rental contracts by (i) taking into account endogenous matching between landlords and tenants, and estimating the joint decisions of partner and contract choice, and (ii) examining the effect of perceived

  11. Relating land use and human intra-city mobility

    CERN Document Server

    Lee, Minjin

    2015-01-01

    Understanding human mobility patterns -- how people move in their everyday lives -- is an interdisciplinary research field. It is a question with roots back to the 19th century that has been dramatically revitalized with the recent increase in data availability. Models of human mobility often take the population distribution as a starting point. Another, sometimes more accurate, data source is land-use maps. In this paper, we discuss how the intra-city movement patterns, and consequently population distribution, can be predicted from such data sources. As a link between, land use and mobility, we show that the purposes of people's trips are strongly correlated with the land use of the trip's origin and destination. We calibrate, validate and discuss our model using survey data.

  12. Effect of noise reducing components on nose landing gear stability for a mid-size aircraft coupled with vortex shedding and freeplay

    Science.gov (United States)

    Eret, Petr; Kennedy, John; Bennett, Gareth J.

    2015-10-01

    In the pursuit of quieter aircraft, significant effort has been dedicated to airframe noise identification and reduction. The landing gear is one of the main sources of airframe noise on approach. The addition of noise abatement technologies such as fairings or wheel hub caps is usually considered to be the simplest solution to reduce this noise. After touchdown, noise abatement components can potentially affect the inherently nonlinear and dynamically complex behaviour (shimmy) of landing gear. Moreover, fairings can influence the aerodynamic load on the system and interact with the mechanical freeplay in the torque link. This paper presents a numerical study of nose landing gear stability for a mid-size aircraft with low noise solutions, which are modelled by an increase of the relevant model structural parameters to address a hypothetical effect of additional fairings and wheel hub caps. The study shows that the wheel hub caps are not a threat to stability. A fairing has a destabilising effect due to the increased moment of inertia of the strut and a stabilising effect due to the increased torsional stiffness of the strut. As the torsional stiffness is dependent on the method of attachment, in situations where the fairing increases the torsional inertia with little increase to the torsional stiffness, a net destabilising effect can result. Alternatively, it is possible that for the case that if the fairing were to increase equally both the torsional stiffness and the moment of inertia of the strut, then their effects could be mutually negated. However, it has been found here that for small and simple fairings, typical of current landing gear noise abatement design, their implementation will not affect the dynamics and stability of the system in an operational range (Fz ≤ 50 000 N, V ≤ 100 m/s). This generalisation is strictly dependent on size and installation methods. The aerodynamic load, which would be influenced by the presence of fairings, was modelled

  13. 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.

  14. 78 FR 18562 - Economic and Environmental Principles and Requirements for Water and Related Land Resources...

    Science.gov (United States)

    2013-03-27

    ... QUALITY Economic and Environmental Principles and Requirements for Water and Related Land Resources... Principles and Requirements. SUMMARY: Section 2031 of the Water Resources Development Act of 2007 (Pub. L... Guidelines for Water and Related Land Resources Implementation Studies'' (Principles and Guidelines),...

  15. Bibliography of Aircraft Gust Measurements in Australia and of Some Related Topics,

    Science.gov (United States)

    1981-09-01

    cold fronts (b) deep southerly streams. Three examples were given, (1) A Qantas flying boat encountered a line squall near Rathmines, the aircraft...Viscount Aircraft VH-TVC, operated by Australian National Airways Pty. Ltd. Air Navigation Regulations, Accident Inquiry, August 1962. This is the report...only Australian data included in this report are the QANTAS Super Constellation data already reported by Heath-Smith (1959), and the 17 hours of

  16. Land

    CSIR Research Space (South Africa)

    Audouin, M

    2007-01-01

    Full Text Available Unsustainable agricultural practices have had a role to play in the degradation of land on which agriculture depends. South Africa has an international obligation to develop a National Action Programme (NAP), the purpose of which is to identify...

  17. 43 CFR 423.41 - Aircraft.

    Science.gov (United States)

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Aircraft. 423.41 Section 423.41 Public... Aircraft. (a) You must comply with any applicable Federal, State, and local laws, and with any additional... this part 423, with respect to aircraft landings, takeoffs, and operation on or in the proximity of...

  18. Study of flutter related computational procedures for minimum weight structural sizing of advanced aircraft

    Science.gov (United States)

    Oconnell, R. F.; Hassig, H. J.; Radovcich, N. A.

    1976-01-01

    Results of a study of the development of flutter modules applicable to automated structural design of advanced aircraft configurations, such as a supersonic transport, are presented. Automated structural design is restricted to automated sizing of the elements of a given structural model. It includes a flutter optimization procedure; i.e., a procedure for arriving at a structure with minimum mass for satisfying flutter constraints. Methods of solving the flutter equation and computing the generalized aerodynamic force coefficients in the repetitive analysis environment of a flutter optimization procedure are studied, and recommended approaches are presented. Five approaches to flutter optimization are explained in detail and compared. An approach to flutter optimization incorporating some of the methods discussed is presented. Problems related to flutter optimization in a realistic design environment are discussed and an integrated approach to the entire flutter task is presented. Recommendations for further investigations are made. Results of numerical evaluations, applying the five methods of flutter optimization to the same design task, are presented.

  19. 36 CFR 331.14 - Aircraft.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Aircraft. 331.14 Section 331..., KENTUCKY AND INDIANA § 331.14 Aircraft. (a) The operation of aircraft on WCA lands and waters is prohibited... prohibited. (c) The provisions of this section shall not be applicable to aircraft engaged on official...

  20. Relationship Study on Land Use Spatial Distribution Structure and Energy-Related Carbon Emission Intensity in Different Land Use Types of Guangdong, China, 1996–2008

    Directory of Open Access Journals (Sweden)

    Yi Huang

    2013-01-01

    Full Text Available This study attempts to discuss the relationship between land use spatial distribution structure and energy-related carbon emission intensity in Guangdong during 1996–2008. We quantized the spatial distribution structure of five land use types including agricultural land, industrial land, residential and commercial land, traffic land, and other land through applying spatial Lorenz curve and Gini coefficient. Then the corresponding energy-related carbon emissions in each type of land were calculated in the study period. Through building the reasonable regression models, we found that the concentration degree of industrial land is negatively correlated with carbon emission intensity in the long term, whereas the concentration degree is positively correlated with carbon emission intensity in agricultural land, residential and commercial land, traffic land, and other land. The results also indicate that land use spatial distribution structure affects carbon emission intensity more intensively than energy efficiency and production efficiency do. These conclusions provide valuable reference to develop comprehensive policies for energy conservation and carbon emission reduction in a new perspective.

  1. 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.

  2. The Land Subsidence and Relative Sea Level Rise in Chinese Delta Areas

    Institute of Scientific and Technical Information of China (English)

    YeYincan; LiuDujuan

    2004-01-01

    Based on some experts' research effort, the problems of land subsidence and relative sea level rise in three Chinese delta areas(Huanghe, Changjiang and Zhujiang Delta) are analyzed and discussed in this paper. The authors' opinion is that the land subsidence is mainly induced by human activity and has made the greater contributions to the relative sea level rise and become one of the geological hazards in these areas. In Tianjin and Shanghai areas where had ever existed serious land subsidence problem, due to the positive and effective control methods, the ratio of man-induced land subsidence to relative sea level rise decreased from 80% - 90% in 1960s - 1970s to less than 60% at present. But it is estimated that in the next tens of years this ratio will still be considerable. So human being must keep its eyes on this phenomenon and take more positive countermeasures to control the land subsidenee.

  3. Relative Humidity as an Indicator for Cloud Formation over Heterogeneous land surfaces

    NARCIS (Netherlands)

    Heerwaarden, van C.C.; Vilà-Guerau de Arellano, J.

    2008-01-01

    The influence of land surface heterogeneity on potential cloud formation is investigated using relative humidity as an indicator. This is done by performing numerical experiments using a large-eddy simulation model (LES). The land surface in the model was divided into two patches that had the same s

  4. Relative impacts of land use and climate change on summer precipitation in the Netherlands

    Science.gov (United States)

    Daniels, Emma; Lenderink, Geert; Hutjes, Ronald; Holtslag, Albert

    2016-10-01

    The effects of historic and future land use on precipitation in the Netherlands are investigated on 18 summer days with similar meteorological conditions. The days are selected with a circulation type classification and a clustering procedure to obtain a homogenous set of days that is expected to favor land impacts. Changes in precipitation are investigated in relation to the present-day climate and land use, and from the perspective of future climate and land use. To that end, the weather research and forecasting (WRF) model is used with land use maps for 1900, 2000, and 2040. In addition, a temperature perturbation of +1 °C assuming constant relative humidity is imposed as a surrogate climate change scenario. Decreases in precipitation of, respectively, 3-5 and 2-5 % are simulated following conversion of historic to present, and present to future, land use. The temperature perturbation under present land use conditions increases precipitation amounts by on average 7-8 % and amplifies precipitation intensity. However, when also considering future land use, the increase is reduced to 2-6 % on average, and no intensification of extreme precipitation is simulated. In all, the simulated effects of land use changes on precipitation in summer are smaller than the effects of climate change, but are not negligible.

  5. Abundance of diurnal raptors in relation to prairie dog colonies: Implications for bird-aircraft strike hazard

    Science.gov (United States)

    Merriman, J.W.; Boal, C.W.; Bashore, T.L.; Zwank, P.J.; Wester, D.B.

    2007-01-01

    Some diurnal raptors are frequently observed at prairie dog (Cynomys sp.) colonies. As a result, some military installations have conducted prairie dog control activities to reduce the bird-aircraft strike hazard (BASH) potential of low-flying aircraft. To evaluate the validity of this management strategy, we assessed raptor associations with prairie dog colonies at 2 short-grass prairie study areas: southern Lubbock County, Texas, USA, and Melrose Bombing and Gunnery Range in east-central New Mexico, USA. We quantified diurnal raptors (i.e., Falconiformes) at plots occupied (colony plots) and unoccupied (noncolony plots) by black-tailed prairie dogs (Cynomys ludovicianus) at both sites throughout 2002. We compared the number of individual birds of a given species at colony and noncolony plots within each study area by season. Ferruginous hawks (Buteo regalis) and northern harriers (Circus cyaneus) were more abundant at colony plots, whereas Swainson's hawks (B. swainsoni) and American kestrels (Falco sparverius) were more abundant at noncolony plots. Red-tailed hawk (B. jamaicensis) abundance did not differ between the 2 plot types. Our results suggest prairie dog control as a method of reducing BASH potential may be effective at some sites but may be ineffective or even increase the BASH potential at others. Thus, bird-avoidance models assessing the BASH potential should be conducted on a site-specific basis using information on relative and seasonal abundances of individual raptor species and the relative strike risks they pose to aircraft.

  6. 32 CFR 855.15 - Detaining an aircraft.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Detaining an aircraft. 855.15 Section 855.15 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE AIRCRAFT CIVIL AIRCRAFT USE OF UNITED STATES AIR FORCE AIRFIELDS Civil Aircraft Landing Permits § 855.15 Detaining an aircraft...

  7. Coordination control of quadrotor VTOL aircraft in three-dimensional space

    Science.gov (United States)

    Do, K. D.

    2015-03-01

    This paper presents a constructive design of distributed coordination controllers for a group of N quadrotor vertical take-off and landing (VTOL) aircraft in three-dimensional space. A combination of Euler angles and unit-quaternion for the attitude representation of the aircraft is used to result in an effective control design, and to reduce singularities in the aircraft's dynamics. The coordination control design is based on a new bounded control design technique for second-order systems and new pairwise collision avoidance functions. The pairwise collision functions are functions of both relative positions and relative velocities between the aircraft instead of only their relative positions as in the literature. To overcome the inherent underactuation of the aircraft, the roll and pitch angles of the aircraft are considered as immediate controls. Simulations illustrate the results.

  8. Evaluation of the Relative Contribution of Observing Systems in Reanalyses: Aircraft Temperature Bias and Analysis Innovations

    Science.gov (United States)

    Bosilovich, Michael G.; Dasilva, Arindo M.

    2012-01-01

    Reanalyses have become important sources of data in weather and climate research. While observations are the most crucial component of the systems, few research projects consider carefully the multitudes of assimilated observations and their impact on the results. This is partly due to the diversity of observations and their individual complexity, but also due to the unfriendly nature of the data formats. Here, we discuss the NASA Modern-Era Retrospective analysis for Research and Applications (MERRA) and a companion dataset, the Gridded Innovations and Observations (GIO). GIO is simply a post-processing of the assimilated observations and their innovations (forecast error and analysis error) to a common spatio-temporal grid, following that of the MERRA analysis fields. This data includes in situ, retrieved and radiance observations that are assimilated and used in the reanalysis. While all these disparate observations and statistics are in a uniform easily accessible format, there are some limitations. Similar observations are binned to the grid, so that multiple observations are combined in the gridding process. The data is then implicitly thinned. Some details in the meta data may also be lost (e.g. aircraft or station ID). Nonetheless, the gridded observations should provide easy access to all the observations input to the reanalysis. To provide an example of the GIO data, a case study evaluating observing systems over the United States and statistics is presented, and demonstrates the evaluation of the observations and the data assimilation. The GIO data is used to collocate 200mb Radiosonde and Aircraft temperature measurements from 1979-2009. A known warm bias of the aircraft measurements is apparent compared to the radiosonde data. However, when larger quantities of aircraft data are available, they dominate the analysis and the radiosonde data become biased against the forecast. When AMSU radiances become available the radiosonde and aircraft analysis and

  9. Greening Ground: Exploring the Relation between Land Market, Land Policy and Sustainable Area Development in the Netherlands

    NARCIS (Netherlands)

    Giezen, M.; Driessen, P.P.J.; Spit, T.J.M.

    2012-01-01

    For decades the land market in the Netherlands has been dominated by an active municipal land policy. Municipalities acquire land, service the land into lots ready for development and develop the desired infrastructure. These lots are sold to developers for further construction. During periods of

  10. Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions.

    Directory of Open Access Journals (Sweden)

    Karyn D Rode

    Full Text Available Recent observations suggest that polar bears (Ursus maritimus are increasingly using land habitats in some parts of their range, where they have minimal access to their preferred prey, likely in response to loss of their sea ice habitat associated with climatic warming. We used location data from female polar bears fit with satellite radio collars to compare land use patterns in the Chukchi Sea between two periods (1986-1995 and 2008-2013 when substantial summer sea-ice loss occurred. In both time periods, polar bears predominantly occupied sea-ice, although land was used during the summer sea-ice retreat and during the winter for maternal denning. However, the proportion of bears on land for > 7 days between August and October increased between the two periods from 20.0% to 38.9%, and the average duration on land increased by 30 days. The majority of bears that used land in the summer and for denning came to Wrangel and Herald Islands (Russia, highlighting the importance of these northernmost land habitats to Chukchi Sea polar bears. Where bears summered and denned, and how long they spent there, was related to the timing and duration of sea ice retreat. Our results are consistent with other studies supporting increased land use as a common response of polar bears to sea-ice loss. Implications of increased land use for Chukchi Sea polar bears are unclear, because a recent study observed no change in body condition or reproductive indices between the two periods considered here. This result suggests that the ecology of this region may provide a degree of resilience to sea ice loss. However, projections of continued sea ice loss suggest that polar bears in the Chukchi Sea and other parts of the Arctic may increasingly use land habitats in the future, which has the potential to increase nutritional stress and human-polar bear interactions.

  11. Simulations and Experiments of Hot Forging Design and Evaluation of the Aircraft Landing Gear Barrel Al Alloy Structure

    Science.gov (United States)

    Ram Prabhu, T.

    2016-04-01

    In the present study, the hot forging design of a typical landing gear barrel was evolved using finite element simulations and validated with experiments. A DEFORM3D software was used to evolve the forging steps to obtain the sound quality part free of defects with minimum press force requirements. The hot forging trial of a barrel structure was carried out in a 30 MN hydraulic press based on the simulation outputs. The tensile properties of the part were evaluated by taking samples from all three orientations (longitudinal, long transverse, short transverse). The hardness and microstructure of the part were also investigated. To study the soundness of the product, fluorescent penetrant inspection and ultrasonic testing were performed in order to identify any potential surface or internal defects in the part. From experiments, it was found that the part was formed successfully without any forging defects such as under filling, laps, or folds that validated the effectiveness of the process simulation. The tensile properties of the part were well above the specification limit (>10%) and the properties variation with respect to the orientation was less than 2.5%. The part has qualified the surface defects level of Mil Std 1907 Grade C and the internal defects level of AMS 2630 Class A (2 mm FBh). The microstructure shows mean grain length and width of 167 and 66 µm in the longitudinal direction. However, microstructure results revealed that the coarse grain structure was observed on the flat surface near the lug region due to the dead zone formation. An innovative and simple method of milling the surface layer after each pressing operation was applied to solve the problem of the surface coarse grain structure.

  12. 多轮多支柱式飞机起落架运动特性仿真研究%Simulation Research on Multiple Wheels and Multiple Strut Aircraft Landing Gear’s Kinetic Characteristic

    Institute of Scientific and Technical Information of China (English)

    王博; 林皓

    2014-01-01

    In order to assess the handling characteristics of the aircraft at taking off and landing stage ,for a com‐plex aircraft landing gear systems ,the single strut landing gear system which is composed by tires ,shock strut system ,brake system and nose wheel steering system is studied ,including force analysis ,torque characteristic and its delivery process .Based on the linear theory and the Matlab/Simulink ,all the strut kinetic characteristics are superimposed together ,that constitutes a simulation model of the system .Moreover ,embedded in aircraft six degree of freedom model and been simulated ,including acceleration taxiing characteristics ,high/low speed turns characteristics ,take‐off characteristics ,landing characteristics and brake characteristics .The model is used in an aircraft moving base simulator for flight test .The simulation result indicates that this model accu‐rately reflects the aircraft attitude response in the process of plane’s taking off and landing .%为了评估起降阶段的飞机操控特性,针对某型飞机多轮多支柱式起落架系统,研究组成单个起落架支柱的轮胎、缓冲器、刹车系统、前轮转弯等部件的受力、力矩特性及传递过程。基于线性理论,将多个支柱运动特性叠加,运用Matlab/Simulink软件工具,建立整个系统的仿真模型。嵌入某型飞机六自由度运动解算模型进行飞机落震、加速滑跑、高低速转弯、起飞离地、着陆接地、刹车减速等仿真验证,并在某型飞机动基座模拟器上进行飞行试验。结果表明:该起落架模型各项功能完善,能够正确反映飞机姿态响应过程,飞机起降过程感受与真实飞机基本一致。

  13. Drop size distributions and related properties of fog for five locations measured from aircraft

    Science.gov (United States)

    Zak, J. Allen

    1994-01-01

    Fog drop size distributions were collected from aircraft as part of the Synthetic Vision Technology Demonstration Program. Three west coast marine advection fogs, one frontal fog, and a radiation fog were sampled from the top of the cloud to the bottom as the aircraft descended on a 3-degree glideslope. Drop size versus altitude versus concentration are shown in three dimensional plots for each 10-meter altitude interval from 1-minute samples. Also shown are median volume radius and liquid water content. Advection fogs contained the largest drops with median volume radius of 5-8 micrometers, although the drop sizes in the radiation fog were also large just above the runway surface. Liquid water content increased with height, and the total number of drops generally increased with time. Multimodal variations in number density and particle size were noted in most samples where there was a peak concentration of small drops (2-5 micrometers) at low altitudes, midaltitude peak of drops 5-11 micrometers, and high-altitude peak of the larger drops (11-15 micrometers and above). These observations are compared with others and corroborate previous results in fog gross properties, although there is considerable variation with time and altitude even in the same type of fog.

  14. 75 FR 66125 - Federal Land Managers' Air Quality Related Values Work Group (FLAG)

    Science.gov (United States)

    2010-10-27

    ... National Park Service Federal Land Managers' Air Quality Related Values Work Group (FLAG) AGENCY: National...' Air Quality Related Values Work Group (FLAG) was formed (1) to develop a more consistent and objective... constituencies (e.g., State air regulatory agencies, concerned citizens, environmental groups,...

  15. Evaluation of Landing Characteristics Achieved by Simulations and Flight Tests on a Small-scaled Model Related to Magnetically Levitated Advanced Take-off and Landing Operations

    NARCIS (Netherlands)

    Rohacs, D.; Voskuijl, M.; Siepenkotter, N.

    2014-01-01

    The goal of this paper is to simulate and measure on a small-scaled model the landing characteristics related to take-off and landing (TOL) operations supported by a magnetic levitation (MAGLEV) system as ground-based power supply. The technical feasibility and the potential benefits of using ground

  16. Evaluation of Landing Characteristics Achieved by Simulations and Flight Tests on a Small-scaled Model Related to Magnetically Levitated Advanced Take-off and Landing Operations

    NARCIS (Netherlands)

    Rohacs, D.; Voskuijl, M.; Siepenkotter, N.

    2014-01-01

    The goal of this paper is to simulate and measure on a small-scaled model the landing characteristics related to take-off and landing (TOL) operations supported by a magnetic levitation (MAGLEV) system as ground-based power supply. The technical feasibility and the potential benefits of using ground

  17. Land use changes and their relations with carbon cycles over the past 300 a in China

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Land use and land cover in China have changed greatly during the past 300 a, indicated by the rapid abrupt decrease of forest land area and the rapid increase of cropland area, which can affect terrestrial carbon cycle greatly. The first-hand materials are used to analyze main characteristics for land use and land cover changes in China during the study period. The following conclusions can be drawn from this study. The cropland area in China kept increasing from 60.78×106 hm2 in 1661 to 96.09×106 hm2 in 1998. Correspondingly, the forest land area decreased from 248.13×106 hm2 in 1700 to 109.01×106 hm2 in 1949. Affected by such changes, the terrestrial ecosystem carbon storage decreased in the mean time. Car-bon lost from land use and land cover changes mainly consist of the loss from vegetation biomass and soil. In the past 300 a, about 3.70 PgC was lost from vegetation biomass, and emissions from soil ranged from 0.80 to 5.84 PgC. The moderate evaluation of soil losses was 2.48 PgC. The total loss from vegetation and soil was between 4.50 and 9.54 PgC. The moderate and optimum evaluation was 6.18 PgC. Such carbon losses distribution varied spatially from region to region. Carbon lost more significantly in Northeast China and Southwest China than in other regions, because losses of forest land in these two regions were far greater than in the other regions during the past 300 a. And losses of carbon in the other regions were also definite, such as Inner Mongolia, the western part of South China, the Xinjiang Uygur Autonomous Region, and the Qinghai-Tibet Plateau. But the carbon lost very little from the traditional agricultural regions in China, such as North China and East China. Studies on the relationship between land use and land cover change and carbon cycle in China show that the land use activities, especially those related to agriculture and forest management, began to affect terrestrial carbon storage positively in recent years.

  18. 19 CFR 122.37 - Precleared aircraft.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Precleared aircraft. 122.37 Section 122.37 Customs... AIR COMMERCE REGULATIONS Landing Requirements § 122.37 Precleared aircraft. (a) Application. This section applies when aircraft carrying crew, passengers and baggage, or merchandise which has been...

  19. Land Use and Land Cover, water related land use 2001, Published in 2008, 1:24000 (1in=2000ft) scale, Box Elder County.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Land Use and Land Cover dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Other information as of 2008. It is described as...

  20. Inventory development and input-output model of U.S. land use: relating land in production to consumption.

    Science.gov (United States)

    Costello, Christine; Griffin, W Michael; Matthews, H Scott; Weber, Christopher L

    2011-06-01

    As populations and demands for land-intensive products, e.g., cattle and biofuels, increase the need to understand the relationship between land use and consumption grows. This paper develops a production-based inventory of land use (i.e., the land used to produce goods) in the U.S. With this inventory an input-output analysis is used to create a consumption-based inventory of land use. This allows for exploration of links between land used in production to the consumption of particular goods. For example, it is possible to estimate the amount of cropland embodied in processed foods or healthcare services. As would be expected, agricultural and forestry industries are the largest users of land in the production-based inventory. Similarly, we find that processed foods and forest products are the largest users of land in the consumption-based inventory. Somewhat less expectedly this work finds that the majority of manufacturing and service industries, not typically associated with land use, require substantial amounts of land to produce output due to the purchase of food and other agricultural and wood-based products in the supply chain. The quantitative land use results of this analysis could be integrated with qualitative metrics such as weighting schemes designed to reflect environmental impact or life cycle impact assessment methods.

  1. 78 FR 16567 - Notice of Opportunity for Public Comment on Non-Rule Making Action To Change Land Use From...

    Science.gov (United States)

    2013-03-15

    ... To Change Land Use From Aeronautical to Non-Aeronautical at Mobile Downtown Airport, Mobile, Alabama... by the Mobile Airport Authority. The airport layout plan update, if approved, would change the land... Commercial Development. The location of the land relative to existing or anticipated aircraft noise...

  2. The Archives of the Holland Land Company in Reed Library and Related New York State Collections. Research Guide No. 56.

    Science.gov (United States)

    Safran, Franciska

    The Holland Land Company Manuscript Preservation Project in Reed Library, State University of New York, College at Fredonia is a grant-supported project concentrating on locating, assessing, and reproducing primary source material that relate to the activities of the Holland Land Company in the United States. The Holland Land Company collections…

  3. 76 FR 62694 - Appeal of Decisions Relating to Occupancy or Use of National Forest System Lands and Resources

    Science.gov (United States)

    2011-10-11

    ... Decisions Relating to Occupancy or Use of National Forest System Lands and Resources AGENCY: USDA, Forest... regulations governing occupancy or use of National Forest System (NFS) lands and resources. The appeal process... lands and resources to appeal certain Forest Service decisions with regard to the issuance, approval, or...

  4. Heavy Metal Content in Chinese Vegetable Plantation Land Soils and Related Source Analysis

    Institute of Scientific and Technical Information of China (English)

    ZENG Xi-bai; LI Lian-fang; MEI Xu-rong

    2008-01-01

    According to the previous literature published since 1989,statistical analysis for reported data on the heavy metals in Chinese vegetable plantation soils was carried out systematically in this article.The purpose of this investigation was to study the status of heavy metal content in vegetable land soils systematically through objective assessment to promote the development of vegetable production with high quality and efficiency.It is concluded that Zn,Cr,Cu had relatively high concentrations while the mean concentrations of toxic metals,As,Hg,Cd were 8.03,0.12,0.28 mg kg-1,respectively with comparatively low concentrations in Chinese vegetable land.Comparing to Chinese Soil Quality Criterion GB 15618-1995 (6.5 < pH < 7.5),about 24.1,10.3,and 9.2% of the total samples was contaminated by Cd,Hg,and As,respectively,and the descending order of heavy metals was Cd > Hg > As > Zn > Cu > Cr > Pb.When compared among different regions,the more serious heavy metal contamination was found in the vegetable land of eastern China and the main contamination elements were Cd,Hg,and Zn.In the mid region,vegetable plantation land soil was mainly polluted by As and Cd,as well as by Hg,Zn,and Cu,to some extent.In the west region of China,Cd and As contamination was also observed to some degree,along with few soil samples exceeding the grade H level of GB 15618-1995 (6.5 < pH < 7.5) for Cu,Cr,and Hg content.Compared to the five vegetable plantation land patterns,the highest concentration of As,Cd,Hg,and Zn occurred in the industrial/sewage irrigation vegetable land,especially for Hg with 2.36 mg kg-1 content averagely,which is 10.5-21.1 times higher than the other four types of vegetable lands.The highest concentration of Cu and Cr occurred in the greenhouse vegetable land soils,and urban vegetable land soil had the highest Pb content in comparison with the other types of vegetable plantation land patterns.By analyzing heavy metal content under different

  5. First Approximations of Prescribed Fire Risks Relative to Other Management Techniques Used on Private Lands.

    Directory of Open Access Journals (Sweden)

    Dirac Twidwell

    Full Text Available Fire is widely recognized as a critical ecological and evolutionary driver that needs to be at the forefront of land management actions if conservation targets are to be met. However, the prevailing view is that prescribed fire is riskier than other land management techniques. Perceived risks associated with the application of fire limits its use and reduces agency support for prescribed burning in the private sector. As a result, considerably less cost-share support is given for prescribed fire compared to mechanical techniques. This study tests the general perception that fire is a riskier technique relative to other land management options. Due to the lack of data available to directly test this notion, we use a combination of approaches including 1 a comparison of fatalities resulting from different occupations that are proxies for techniques employed in land management, 2 a comparison of fatalities resulting from wildland fire versus prescribed fire, and 3 an exploration of causal factors responsible for wildland fire-related fatalities. This approach establishes a first approximation of the relative risk of fatality to private citizens using prescribed fire compared to other management techniques that are readily used in ecosystem management. Our data do not support using risks of landowner fatalities as justification for the use of alternative land management techniques, such as mechanical (machine-related equipment, over prescribed fire. Vehicles and heavy machinery are consistently leading reasons for fatalities within occupations selected as proxies for management techniques employed by ranchers and agricultural producers, and also constitute a large proportion of fatalities among firefighters. Our study provides the foundation for agencies to establish data-driven decisions regarding the degree of support they provide for prescribed burning on private lands.

  6. Instruments of Enhancing the Effectiveness of State Regulation of Land -lease Relations in Ukraine

    OpenAIRE

    Pomaza-Ponomarenko Alina Leonidovna

    2014-01-01

    Enhancing the effectiveness of state regulation of the land lease relations is an actual problem for Ukraine, which is proposed to solve through the involvement of civil society institutions. In this regard, the elements of public evaluation results of public authorities` operation in the said sphere have been determined.

  7. Real-time Terrain Relative Navigation Test Results from a Relevant Environment for Mars Landing

    Science.gov (United States)

    Johnson, Andrew E.; Cheng, Yang; Montgomery, James; Trawny, Nikolas; Tweddle, Brent; Zheng, Jason

    2015-01-01

    Terrain Relative Navigation (TRN) is an on-board GN&C function that generates a position estimate of a spacecraft relative to a map of a planetary surface. When coupled with a divert, the position estimate enables access to more challenging landing sites through pin-point landing or large hazard avoidance. The Lander Vision System (LVS) is a smart sensor system that performs terrain relative navigation by matching descent camera imagery to a map of the landing site and then fusing this with inertial measurements to obtain high rate map relative position, velocity and attitude estimates. A prototype of the LVS was recently tested in a helicopter field test over Mars analog terrain at altitudes representative of Mars Entry Descent and Landing conditions. TRN ran in real-time on the LVS during the flights without human intervention or tuning. The system was able to compute estimates accurate to 40m (3 sigma) in 10 seconds on a flight like processing system. This paper describes the Mars operational test space definition, how the field test was designed to cover that operational envelope, the resulting TRN performance across the envelope and an assessment of test space coverage.

  8. Prospective Study of the Relation between Landing Biomechanics and Jumper's Knee

    NARCIS (Netherlands)

    van der Worp, H.; van der Does, H. T. D.; Brink, M. S.; Zwerver, J.; Hijmans, J. M.

    The literature on the relation between jump biomechanics and jumper's knee indicates that a jump with horizontal displacement poses a threat for developing jumper's knee. Subjects with jumper's knee have been shown to display a stiff landing pattern characterized by a small range of motion. However,

  9. Prospective Study of the Relation between Landing Biomechanics and Jumper's Knee

    NARCIS (Netherlands)

    van der Worp, H.; van der Does, H. T. D.; Brink, M. S.; Zwerver, J.; Hijmans, J. M.

    2016-01-01

    The literature on the relation between jump biomechanics and jumper's knee indicates that a jump with horizontal displacement poses a threat for developing jumper's knee. Subjects with jumper's knee have been shown to display a stiff landing pattern characterized by a small range of motion. However,

  10. A NEW LAND-BASED AIRCRAFT PRECISION APPROACH BASED ON PPP%基于精密单点定位的陆基飞机精密进近着陆方法研究

    Institute of Scientific and Technical Information of China (English)

    郑坤; 高翔; 李晓宇; 贾蕊溪

    2014-01-01

    基于精密单点定位技术提出一种新的陆基飞机精密进近着陆方法.该方法高程方向精度在0.5m,水平方向精度在0.2m,满足陆基精密进近着陆要求.还提出一种精密星历压缩方法,基于该方法两条北斗短报文即可满足2h的精密单点定位.%A new land-based aircraft precision approach based on precise point positioning technology was proposed,which can support the blind landing of fixed-wing aircraft,helicopters and unmanned aerial vehicles.The approach can reduce the risk of landing in bad weather and greatly simplifies the airport equipment and reduce the cost of construction of the airport.Moreover,a precise ephemeris compression method was presented in the paper,which can meet two hours of precise point positioning using two Beidou short messages.

  11. Causal Factors and Adverse Conditions of Aviation Accidents and Incidents Related to Integrated Resilient Aircraft Control

    Science.gov (United States)

    Reveley, Mary S.; Briggs, Jeffrey L.; Evans, Joni K.; Sandifer, Carl E.; Jones, Sharon Monica

    2010-01-01

    The causal factors of accidents from the National Transportation Safety Board (NTSB) database and incidents from the Federal Aviation Administration (FAA) database associated with loss of control (LOC) were examined for four types of operations (i.e., Federal Aviation Regulation Part 121, Part 135 Scheduled, Part 135 Nonscheduled, and Part 91) for the years 1988 to 2004. In-flight LOC is a serious aviation problem. Well over half of the LOC accidents included at least one fatality (80 percent in Part 121), and roughly half of all aviation fatalities in the studied time period occurred in conjunction with LOC. An adverse events table was updated to provide focus to the technology validation strategy of the Integrated Resilient Aircraft Control (IRAC) Project. The table contains three types of adverse conditions: failure, damage, and upset. Thirteen different adverse condition subtypes were gleaned from the Aviation Safety Reporting System (ASRS), the FAA Accident and Incident database, and the NTSB database. The severity and frequency of the damage conditions, initial test conditions, and milestones references are also provided.

  12. 77 FR 42455 - Airworthiness Directives; Piper Aircraft, Inc. Airplanes

    Science.gov (United States)

    2012-07-19

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

  13. Shod landing provides enhanced energy dissipation at the knee joint relative to barefoot landing from different heights.

    Science.gov (United States)

    Yeow, C H; Lee, P V S; Goh, J C H

    2011-12-01

    Athletic shoes can directly provide shock absorption at the foot due to its cushioning properties, however it remains unclear how these shoes may affect the level of energy dissipation contributed by the knee joint. This study sought to investigate biomechanical differences, in terms of knee kinematics, kinetics and energetics, between barefoot and shod landing from different heights. Twelve healthy male recreational athletes were recruited and instructed to perform double-leg landing from 0.3-m and 0.6-m heights in barefoot and shod conditions. The shoe model tested was Brooks Maximus II. Markers were placed on the subjects based on the Plug-in Gait Marker Set. Force-plates and motion-capture system were used to capture ground reaction force (GRF) and kinematics data respectively. 2×2-ANOVA (barefoot/shod condition×landing height) was performed to examine differences in knee kinematics, kinetics and energetics between barefoot and shod conditions from different landing heights. Peak GRF was not significantly different (p=0.732-0.824) between barefoot and shod conditions for both landing heights. Knee range-of-motion, flexion angular velocity, external knee flexion moment, and joint power and work were higher during shod landing (pbarefoot landing for both landing heights. No significant interactions (p=0.073-0.933) were found between landing height and barefoot/shod condition for the tested parameters. While the increase in landing height can elevate knee energetics independent of barefoot/shod conditions, we have also shown that the shod condition was able to augment the level of energy dissipation contributed by the knee joint, via the knee extensors, regardless of the tested landing heights.

  14. Aircraft operations management manual

    Science.gov (United States)

    1992-01-01

    The NASA aircraft operations program is a multifaceted, highly diverse entity that directly supports the agency mission in aeronautical research and development, space science and applications, space flight, astronaut readiness training, and related activities through research and development, program support, and mission management aircraft operations flights. Users of the program are interagency, inter-government, international, and the business community. This manual provides guidelines to establish policy for the management of NASA aircraft resources, aircraft operations, and related matters. This policy is an integral part of and must be followed when establishing field installation policy and procedures covering the management of NASA aircraft operations. Each operating location will develop appropriate local procedures that conform with the requirements of this handbook. This manual should be used in conjunction with other governing instructions, handbooks, and manuals.

  15. Using Remotely Piloted Aircraft System to Study the Evolution of the Boundary Layer Related to Fog Events

    Science.gov (United States)

    Roberts, G. C.; Cayez, G.; Ronflé-Nadaud, C.; Albrand, M.; Dralet, J. P.; Momboisse, G.; Nicoll, K.; Seity, Y.; Bronz, M.; Hattenberger, G.; Gorraz, M.; Bustico, A.

    2014-12-01

    Over the past decade, the scientific community has embraced the use of RPAS (remotely piloted aircraft system) as a tool to improve observations of the Earth's surface and atmospheric phenomena. The use of small RPAS (Remotely Piloted Aircraft System) in atmospheric research has increased because of their relative low-cost, compact size and ease of operation. Small RPAS are especially adapted for observing the atmospheric boundary layer processes at high vertical and temporal resolution. To this end, CNRM, ENAC, and ENM have developed the VOLTIGE (Vecteurs d'Observation de La Troposphere pour l'Investigation et la Gestion de l'Environnement) program to study the life cycle of fog with multiple, small RPAS. The instrumented RPAS flights have successfully observed the evolution of the boundary layer and dissipation of fog events. In addition, vertical profiles from the RPAS have been compared with Météo France forecast models, and the results suggest that forecast models may be improved using high resolution and frequent in-situ measurements. Within the VOLTIGE project, a flying-wing RPAS with four control surfaces was developed to separate elevator and aileron controls in order to reduce the pitch angle envelope and improve turbulence and albedo measurements. The result leads to a small RPAS with the capability of flying up to two hours with 150 grams of payload, while keeping the hand-launch capability as a constraint for regular atmospheric research missions. High frequency data logging has been integrated into the main autopilot in order to synchronize navigation and payload measurements, as well as allowing an efficient sensor-based navigation. The VOLTIGE program also encourages direct participation of students on the advancement of novel observing systems for atmospheric sciences, and provides a step towards deploying small RPAS in an operational network. VOLTIGE is funded by the Agence Nationale de Recherche (ANR-Blanc 2012) and supported by Aerospace

  16. Aircraft Flight Path Detection and Risk Identification in Landing Phase%着陆阶段航空器航迹检测与风险识别方法

    Institute of Scientific and Technical Information of China (English)

    岳仁田; 焦阳; 赵嶷飞

    2015-01-01

    进近着陆是整个飞行过程中最易发生危险的阶段.目前着陆阶段的风险识别只能依靠塔台管制员的目视观察.在飞行员技术不熟练、起降频繁的通用航空飞行训练中,目视观察很难准确掌握情况,也因此蕴含了巨大的安全风险.利用视频监视航空器着陆行为,同时提出了一种适合复杂背景下小目标分割算法,从视频中提取航空器着陆航迹;并以此为基础进一步识别降落过程中的运行风险.通过对多组不同角度的视频监视数据验证,该算法可在复杂背景下实现航空器着陆航迹的跟踪、落地时刻的判断及危险滑行航迹的准确识别,对于保障飞行安全具有重要的现实意义.%The landing is the most dangerous stage of the flight. At present, the risk recognition in landing stage only rely on visual observation of tower controller. In general aviation training when the pilot is unskilled and contains frequently taking off and landing, it is very difficult for visual observation to completely handle the situation, therefore it contains a huge safety risk. In this paper, the data of video surveillance is used to track the landing of aircraft, a small target segmentation algorithm is proposed which is suitable for the complex background at the same time;and based on this, the operational risk of the landing process is further identified. It is verified by the video surveillance data from different point of view, the algorithm can achieve the tracking of aircraft landing path under complex background, judgment of landing moments and accurate recognition of dangerous sliding path, which has important practical significance to ensure flight safety.

  17. An Approximate Method of Calculation of Relative Humidity Required to Prevent Frosting on Inside of Aircraft Pressure Cabin Windows, Special Report

    Science.gov (United States)

    Jones, Alun R.

    1940-01-01

    This report has been prepare in response to a request for information from an aircraft company. A typical example was selected for the presentation of an approximate method of calculation of the relative humidity required to prevent frosting on the inside of a plastic window in a pressure type cabin on a high speed airplane. The results of the study are reviewed.

  18. Interaction of Aircraft Wakes From Laterally Spaced Aircraft

    Science.gov (United States)

    Proctor, Fred H.

    2009-01-01

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

  19. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    Science.gov (United States)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

  20. SGP Cloud and Land Surface Interaction Campaign (CLASIC): Measurement Platforms

    Energy Technology Data Exchange (ETDEWEB)

    MA Miller; R Avissar; LK Berg; SA Edgerton; ML Fischer; TJ Jackson; B. Kustas; PJ Lamb; G McFarquhar; Q Min; B Schmid; MS Torn; DD Tuner

    2007-06-01

    The Cloud and Land Surface Interaction Campaign (CLASIC) will be conducted from June 8 to June 30, 2007, at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) Southern Great Plains (SGP) site. Data will be collected using eight aircraft equipped with a variety of specialized sensors, four specially instrumented surface sites, and two prototype surface radar systems. The architecture of CLASIC includes a high-altitude surveillance aircraft and enhanced vertical thermodynamic and wind profile measurements that will characterize the synoptic scale structure of the clouds and the land surface within the ACRF SGP site. Mesoscale and microscale structures will be sampled with a variety of aircraft, surface, and radar observations. An overview of the measurement platforms that will be used during the CLASIC are described in this report. The coordination of measurements, especially as it relates to aircraft flight plans, will be discussed in the CLASIC Implementation Plan.

  1. Guarding against land-expropriation-related mass incidents (LERMIs): Practical evidence from China's local governments

    Science.gov (United States)

    Tan, Shukui; Wang, Siliang

    2017-04-01

    China is faced with serious challenges brought by large-scale social protests in the period of rapid urbanization and profound social transition. In rural areas, the vast majority of mass incidents were related with land expropriation. In this paper, we intend to show how China's local governments guard against land-expropriation-related mass incidents (LERMIs) at the practical level. We first construct a comprehensive three-dimensional theoretic framework to define the boundary, to uncover the incentives, and to recognize the features of involved practices, then, on the basis of description evidenced by detailed data and/or cases, break various local practices down into two categories, the common local practices which refer to the nationwide top-down responses to the unified deployment by the central authority that aims to mitigate discontentment of land-deprived peasants and reduce the probabilities of conflicts through regulating land expropriation behavior and safeguarding economic interests and participation rights of affected peasants, and the specific local practices which point to the innovative local government behaviors with heterogeneity, in general, the tactical approaches to reduce the probabilities of disputes or conflicts evolving into group actions. We further argue that both of them follow a central tenet of instrumental orientation. As to the former, it is corroborated by local governments' paying more attention to promote the stylization and quantification in the aspects of regulating procedure, formulating and renewing compensation standards, resolving disputes, and evaluating risks, while the latter is mainly reflected from the outcome-orientation organization strategies to maintain overall stability in a relatively short term.

  2. Land-Cover Phenologies and Their Relation to Climatic Variables in an Anthropogenically Impacted Mediterranean Coastal Area

    OpenAIRE

    Hernández, Encarni I.; Magaly Koch; Ignacio Gómez; Jose Navarro-Pedreño; Ignacio Melendez-Pastor

    2010-01-01

    Mediterranean coastal areas are experiencing rapid land cover change caused by human-induced land degradation and extreme climatic events. Vegetation index time series provide a useful way to monitor vegetation phenological variations. This study quantitatively describes Enhanced Vegetation Index (EVI) temporal changes for Mediterranean land-covers from the perspective of vegetation phenology and its relation with climate. A time series from 2001 to 2007 of the MODIS Enhanced Vegetation Index...

  3. Aircraft Carriers

    DEFF Research Database (Denmark)

    Nødskov, Kim; Kværnø, Ole

    There are many indications that China is actively researching the design of an aircraft carrier. It is unknown whether China will initiate the actual acquisition of a carrier, but the indications that are available of their research into aircraft carriers and carrier-capable aircraft, as well...... as their purchases of aircraft carrier systems, makes it more than likely that the country is preparing such an acquisition. China has territorial disputes in the South China Sea over the Spratly Islands and is also worried about the security of its sea lines of communications, by which China transports the majority...... of its foreign trade, as well as its oil imports, upon which the country is totally dependent. China therefore has good reasons for acquiring an aircraft carrier to enable it to protect its national interests. An aircraft carrier would also be a prominent symbol of China’s future status as a great power...

  4. Nuisance Flooding and Relative Sea-Level Rise: the Importance of Present-Day Land Motion.

    Science.gov (United States)

    Karegar, Makan A; Dixon, Timothy H; Malservisi, Rocco; Kusche, Jürgen; Engelhart, Simon E

    2017-09-11

    Sea-level rise is beginning to cause increased inundation of many low-lying coastal areas. While most of Earth's coastal areas are at risk, areas that will be affected first are characterized by several additional factors. These include regional oceanographic and meteorological effects and/or land subsidence that cause relative sea level to rise faster than the global average. For catastrophic coastal flooding, when wind-driven storm surge inundates large areas, the relative contribution of sea-level rise to the frequency of these events is difficult to evaluate. For small scale "nuisance flooding," often associated with high tides, recent increases in frequency are more clearly linked to sea-level rise and global warming. While both types of flooding are likely to increase in the future, only nuisance flooding is an early indicator of areas that will eventually experience increased catastrophic flooding and land loss. Here we assess the frequency and location of nuisance flooding along the eastern seaboard of North America. We show that vertical land motion induced by recent anthropogenic activity and glacial isostatic adjustment are contributing factors for increased nuisance flooding. Our results have implications for flood susceptibility, forecasting and mitigation, including management of groundwater extraction from coastal aquifers.

  5. The Marketization of Land-related Indicators Based on the Practice in Anhui Province

    Institute of Scientific and Technical Information of China (English)

    Mengmeng; XU; Zhongxiang; YU; Xilian; YANG

    2015-01-01

    Under the background of the new urbanization,this paper performs an empirical analysis of requisition-compensation balance indicators in Chuzhou City,and points out the problems in the land transaction.At the national level,it is necessary to introduce the measures to regulate the market transactions of requisition-compensation balance indicators as soon as possible,put safeguarding the interests of the majority of farmers in the first place during market transactions,and establish the a unified market platform for the transaction of land-related indicators,so as to boost the urban construction,promote the integration of urban and rural areas,and speed up the new urbanization process.

  6. A Vision-Based Relative Navigation Approach for Autonomous Multirotor Aircraft

    Science.gov (United States)

    Leishman, Robert C.

    Autonomous flight in unstructured, confined, and unknown GPS-denied environments is a challenging problem. Solutions could be tremendously beneficial for scenarios that require information about areas that are difficult to access and that present a great amount of risk. The goal of this research is to develop a new framework that enables improved solutions to this problem and to validate the approach with experiments using a hardware prototype. In Chapter 2 we examine the consequences and practical aspects of using an improved dynamic model for multirotor state estimation, using only IMU measurements. The improved model correctly explains the measurements available from the accelerometers on a multirotor. We provide hardware results demonstrating the improved attitude, velocity and even position estimates that can be achieved through the use of this model. We propose a new architecture to simplify some of the challenges that constrain GPS-denied aerial flight in Chapter 3. At the core, the approach combines visual graph-SLAM with a multiplicative extended Kalman filter (MEKF). More importantly, we depart from the common practice of estimating global states and instead keep the position and yaw states of the MEKF relative to the current node in the map. This relative navigation approach provides a tremendous benefit compared to maintaining estimates with respect to a single global coordinate frame. We discuss the architecture of this new system and provide important details for each component. We verify the approach with goal-directed autonomous flight-test results. The MEKF is the basis of the new relative navigation approach and is detailed in Chapter 4. We derive the relative filter and show how the states must be augmented and marginalized each time a new node is declared. The relative estimation approach is verified using hardware flight test results accompanied by comparisons to motion capture truth. Additionally, flight results with estimates in the control

  7. 14 CFR 298.63 - Reporting of aircraft operating expenses and related statistics by small certificated air carriers.

    Science.gov (United States)

    2010-01-01

    ... OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS..., which is available from the BTS' Office of Airline Information. In the space provided for “Aircraft Code...

  8. Lightning hazards to aircraft

    Science.gov (United States)

    Corn, P. B.

    1978-01-01

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

  9. Using Landsat Thematic Mapper (TM) sensor to detect change in land surface temperature in relation to land use change in Yazd, Iran

    Science.gov (United States)

    Zareie, Sajad; Khosravi, Hassan; Nasiri, Abouzar; Dastorani, Mostafa

    2016-11-01

    Land surface temperature (LST) is one of the key parameters in the physics of land surface processes from local to global scales, and it is one of the indicators of environmental quality. Evaluation of the surface temperature distribution and its relation to existing land use types are very important to the investigation of the urban microclimate. In arid and semi-arid regions, understanding the role of land use changes in the formation of urban heat islands is necessary for urban planning to control or reduce surface temperature. The internal factors and environmental conditions of Yazd city have important roles in the formation of special thermal conditions in Iran. In this paper, we used the temperature-emissivity separation (TES) algorithm for LST retrieving from the TIRS (Thermal Infrared Sensor) data of the Landsat Thematic Mapper (TM). The root mean square error (RMSE) and coefficient of determination (R2) were used for validation of retrieved LST values. The RMSE of 0.9 and 0.87 °C and R2 of 0.98 and 0.99 were obtained for the 1998 and 2009 images, respectively. Land use types for the city of Yazd were identified and relationships between land use types, land surface temperature and normalized difference vegetation index (NDVI) were analyzed. The Kappa coefficient and overall accuracy were calculated for accuracy assessment of land use classification. The Kappa coefficient values are 0.96 and 0.95 and the overall accuracy values are 0.97 and 0.95 for the 1998 and 2009 classified images, respectively. The results showed an increase of 1.45 °C in the average surface temperature. The results of this study showed that optical and thermal remote sensing methodologies can be used to research urban environmental parameters. Finally, it was found that special thermal conditions in Yazd were formed by land use changes. Increasing the area of asphalt roads, residential, commercial and industrial land use types and decreasing the area of the parks, green spaces and

  10. Role of soil biology and soil functions in relation to land use intensity.

    Science.gov (United States)

    Bondi, Giulia; Wall, David; Bacher, Matthias; Emmet-Booth, Jeremy; Graça, Jessica; Marongiu, Irene; Creamer, Rachel

    2017-04-01

    The delivery of the ecosystem's functions is predominantly controlled by soil biology. The biology found in a gram of soil contains more than ten thousand individual species of bacteria and fungi (Torsvik et al., 1990). Understanding the role and the requirements of these organisms is essential for the protection and the sustainable use of soils. Soil biology represents the engine of all the processes occurring in the soil and it supports the ecosystem services such as: 1) nutrient mineralisation 2) plant production 3) water purification and regulation and 4) carbon cycling and storage. During the last years land management type and intensity have been identified as major drivers for microbial performance in soil. For this reason land management needs to be appropriately studied to understand the role of soil biology within this complex interplay of functions. We aimed to study whether and how land management drives soil biological processes and related functions. To reach this objective we built a land use intensity index (LUI) able to quantify the impact of the common farming practices carried out in Irish grassland soils. The LUI is derived from a detailed farmer questionnaire on grassland management practices at 38 farms distributed in the five major agro-climatic regions of Ireland defined by Holden and Brereton (2004). Soils were classified based on their drainage status according to the Irish Soil Information System by Creamer et al. (2014). This detailed questionnaire is then summarised into 3 management intensity components: (i) intensity of Fertilisation (Fi), (ii) frequency of Mowing (Mi) and (iii) intensity of Livestock Grazing (Gi). Sites were sampled to assess the impact of land management intensity on microbial community structure and enzyme behaviour in relation to nitrogen, phosphorus and carbon cycling. Preliminary results for enzymes linked to C and N cycles showed higher activity in relation to low grazing pressure (low Gi). Enzymes linked to P

  11. Soc stock in different forest-related land-uses in central Stara planina mountain, Bulgaria

    Directory of Open Access Journals (Sweden)

    Zhiyanski Miglena

    2009-01-01

    Full Text Available Forest conversions may lead to an accumulation of carbon in vegetation, but little is known about changes in soil C storage with establishment of plantation forests. Understanding these effects is important to addressing issues relevant to ecosystem function and productivity, and to global balance of carbon. The study investigated the effects of the created coniferous plantations on former beech and pasture sites on the soil organic carbon storage. The major forest-related land-uses in the high mountainous regions of central Stara Planina Mountain were investigated: mountainous pasture, coniferous plantations (planted on previous pasture and beech forests between four and five decades ago and natural beech forests. The experimental data of soil properties, conducted in 2005, 2006 and 2007, were used in determining the variations in organic carbon storage in forest litter and in mineral soil under different land-use patterns. At each site five representative soil profiles were opened and described giving a total 75 soil samples from the soil layers respectively at 0-10, 10-30 and 30-50 cm depth. A total of 55 samples from forest floor layers (Aol, Aof, Aoh and greensward were collected with 25:25 cm plastic frame. The main soil properties were determined in accordance with the standardized methods in the Laboratory of soil science at the Forest Research Institute - BAS. The IPCC Good Practice Guidance for Land Use, Land Use Change and Forestry was used to estimate the soil organic carbon stock in soil and litter. The results obtained showed that the SOC stock was quite similar among forest land-uses. The conversion of natural beech forests to coniferous plantations in studied region is related with slightly expressed decrease in soil carbon storage. The values of SOC stocks in 0-50 cm soil layer in these sites were 8.5 (±2.1 tones/ha for pine and 11.0 (±1.4 tones/ha for spruce, while under the natural beech forest it was 14.8 (±1.0 tones

  12. The fatigue life analysis and optimization of landing gear for a large amphibian aircraft%大型水陆两栖飞机起落架疲劳寿命分析与优化

    Institute of Scientific and Technical Information of China (English)

    姜成杰; 许锋

    2015-01-01

    以疲劳寿命分析理论成果为指导,对大型水陆两栖飞机主起落架进行疲劳寿命计算分析与结构优化研究。通过Hypermesh进行模型有限元前处理,在NASTRAN中计算应力分布结果,利用NcodeDesignlife研究起落架整体结构件疲劳寿命;通过LMS Virtual.Lab建立前起落架刚柔耦合模型,得到各个零部件连接部位节点力,从而完成对各个零部件的独立建模分析计算;基于疲劳寿命的结构优化技术,以Optistruct为工具对起落架疲劳寿命薄弱部位进行形状优化,使得疲劳寿命进一步提高。%Based on the theory of fatigue life analysis , it describes the fatigue life analysis and optimization of the main landing gear for a large amphibian aircraft .It builds the landing gear element model in Hypermesh , calcu-lates the distribution in NASTRAN , analyzes the landing gear overall structure fatigue life in NcodeDesignlife .It establishes the rigid flexible coupling model of the main landing gear and obtains the node forces of all connected parts through LMS Virtual .Lab, sets up the models one by one for each parts to obtain the more accurate fatigue life of each parts.At last, based on the fatigue life structure optimization technology , it realizes the shape optimi-zation for the positions of the main landing gear with little fatigue life to make further improvement in Optistruct .

  13. 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.

  14. Flight tests of three-dimensional path-redefinition algorithms for transition from Radio Navigation (RNAV) to Microwave Landing System (MLS) navigation when flying an aircraft on autopilot

    Science.gov (United States)

    Hueschen, Richard M.

    1988-01-01

    This report contains results of flight tests for three path update algorithms designed to provide smooth transition for an aircraft guidance system from DME, VORTAC, and barometric navaids to the more precise MLS by modifying the desired 3-D flight path. The first algorithm, called Zero Cross Track, eliminates the discontinuity in cross-track and altitude error at transition by designating the first valid MLS aircraft position as the desired first waypoint, while retaining all subsequent waypoints. The discontinuity in track angle is left unaltered. The second, called Tangent Path, also eliminates the discontinuity in cross-track and altitude errors and chooses a new desired heading to be tangent to the next oncoming circular arc turn. The third, called Continued Track, eliminates the discontinuity in cross-track, altitude, and track angle errors by accepting the current MLS position and track angle as the desired ones and recomputes the location of the next waypoint. The flight tests were conducted on the Transportation Systems Research Vehicle, a small twin-jet transport aircraft modified for research under the Advanced Transport Operating Systems program at Langley Research Center. The flight tests showed that the algorithms provided a smooth transition to MLS.

  15. Molecular Phylogenetic Information on the Identity of the Closest Living Relative(s) of Land Vertebrates

    Science.gov (United States)

    Zardoya, Rafael; Meyer, Axel

    The phylogenetic position of tetrapods relative to the other two living sarcopterygian lineages (lungfishes and the coelacanth) has been subject to debate for many decades, yet remains unresolved. There are three possible alternatives for the phylogenetic relationships among these three living lineages of sarcopterygians, i.e., lungfish as living sister group of tetrapods, the coelacanth as closest living relative of tetrapods, and lungfish and coelacanth equally closely related to tetrapods. To resolve this important evolutionary question several molecular data sets have been collected in recent years, the largest being the almost complete 28S rRNA gene sequences (about 3500bp) and the complete mitochondrial genomes of the coelacanth and a lungfish (about 16500bp each). Phylogenetic analyses of several molecular data sets had not provided unequivocal support for any of the three hypotheses. However, a lungfish+tetrapod or a lungfish+coelacanth clade were predominantly favored over a coelacanth+tetrapod grouping when the entire mitochondrial genomes alone or in combination with the nuclear 28S rRNA gene data were analyzed with maximum parsimony, neighbor-joining, and maximum likelihood phylogenetic methods. Also, current paleontological and morphological data seem to concur with these molecular results. Therefore the currently available molecular data seems to rule out a coelacanth+tetrapod relationship, the traditional textbook hypothesis. These tentative molecular phylogenetic results point to the inherent difficulty in resolving relationships among lineages which apparently originated in rapid succession during the Devonian.

  16. Global spatial assessment of WUI and related land cover in Portugal

    Science.gov (United States)

    Tonini, Marj; Parente, Joana; Pereira, Mário G.

    2017-04-01

    Forest fires as hazardous events are assuming an increasing importance all around the world, especially in relation to climate changes and to urban sprawl, which makes it difficult to outline a border between human infrastructures and wildland areas. This zone, known as the Wildland Urban Interface (WUI), is defined as the area where structures and other human development meet or intermingle with undeveloped wildland (USDA 2001). Its extension is influenced by anthropogenic features, since, as it was proved, the distance to roads and houses negatively influence the probability of forest fires ignitions, while the population density positively affects it. Land use is also a crucial feature to be considered in the analyses of the impact of forest fires, and each natural, semi-natural and artificial land cover can be affected in a different proportion. The aim of the present study is to investigate and mapping the wildland urban interface and its temporal dynamic in Portugal at global scale. Secondly, it aims at providing a quantitative characterization of forest fires occurred in the last few decades (1990 - 2012) in relation to the burned area and the land covers evolution. The National mapping burnt area dataset (by the Institute for the Conservation of Nature and Forests) provided the information allowing to precisely localize forest fires. The land cover classes were derived from the Corinne Land Cover, available for four periods (1990-2000-2006-2012). The following two classes were retained to outline the WUI: 1) artificial surfaces, as representative of the human development; 2) forest and semi-natural area, as representative of undeveloped wildland. First, we investigated the distribution of the burned areas among the different detailed land covers classes. Then, to map the WUI, we considered a buffer distance around artificial surfaces located in proximity of forests and semi-natural areas. The descriptive statistic carried out individually within each

  17. Aircraft Survivability. Susceptibility Reduction. Fall 2010

    Science.gov (United States)

    2010-01-01

    to determine the degree of control available with manual manipulation of engine throttles for various transport aircraft. Simulations included...Boeing 727, 737, 747, 757, 767, 777, MD-11, MD-90, C-17, and Airbus A320 and A300 transport aircraft. Preliminary missile impact effects were...shown, for most aircraft tested, that using only manual TOC it is very difficult to make a safe runway landing due to difficulty in controlling the

  18. Aircraft electromagnetic compatibility

    Science.gov (United States)

    Clarke, Clifton A.; Larsen, William E.

    1987-06-01

    Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.

  19. Role of land use change in landslide-related sediment fluxes in tropical mountain regions

    Science.gov (United States)

    Guns, M.; Vanacker, V.; Demoulin, A.

    2012-04-01

    Tropical mountain regions are characterised by high denudation rates. Landslides are known to be recurrent phenomena in active mountain belts, but their contribution to the overall sedimentary fluxes is not yet well known. Previous studies on sedimentary cascades have mostly focused on natural environments, without considering the impact of human and/or anthropogenic disturbances on sedimentary budgets. In our work, we hypothesise that human-induced land use change might alter the sediment cascade through shifts in the landslide magnitude-frequency relationship. We have tested this assumption in the Virgen Yacu catchment (approximately 11km2), in the Ecuadorian Cordillera Occidental. Landslide inventories and land use maps were established based on a series of sequential aerial photos (1963, 1977, 1984 and 1989), a HR Landsat image (2001) and a VHR WorldView2 image (2010). Aerial photographs were ortho-rectified, and coregistred with the WorldView2 satellite image. Field campaigns were realised in 2010 and 2011 to collect field-based data on landslide type and geometry (depth, width and length). This allowed us to establish an empirical relationship between landslide area and volume, which was then applied to the landslide inventories to estimate landslide-related sediment production rates for various time periods. The contribution of landslides to the overall sediment flux of the catchment was estimated by comparing the landslide-related sediment production to the total sediment yield. The empirical landslide area-volume relationship established here for the Ecuadorian Andes is similar to that derived for the Himalayas. It suggests that landslides are the main source of sediment in this mountainous catchment. First calculations indicate that human-induced land use change alters the magnitude-frequency relationship through strong increase of small landslides.

  20. Aircraft with Forward Sweeping T-Tail

    Science.gov (United States)

    Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

    2017-01-01

    An aircraft includes a propulsor supported within an aft portion of the fuselage. A thrust reverser is supported proximate the propulsor for redirecting thrust forward to slow the aircraft upon landing. A tail extending from the aft portion of the fuselage is angled forward away from the aft portion and out of the discharge of airflow from the thrust reverser.

  1. 某型飞机前起落架顶起装置设计和实现%Design and Implementation of Nose Landing Gear Jack-up Equipment of an Aircraft

    Institute of Scientific and Technical Information of China (English)

    顾星

    2014-01-01

    The article introduces an aircraft nose landing gear jack-up equipment which is used for simulating an aircraft's nose landing gear swerving test. The main scheme is introduced and the equipment is driven by air. The jack-up actuator is designed as body with three supports and road wheels, this kind of design can not only provide the enough strength and stiffness but also be moved easily. The electrical control section controls the magnetic exchange valve to supply air for the double-acting cylinder, this can achieve the actuator up and down. The equipment is sutably designed with not too much structures and it can be easily maintained, operated and moved, it also has breakdown protection, limit protection and urgency outage protection.%该文介绍了为配合模拟某型飞机的前轮转弯试验设计的前起落架顶起装置,给出了其总体方案。装置采用气源驱动,顶起执行机构采用三角支撑架体并配有行走轮,保证机构强度和刚度的同时又便于移动,电气控制部分控制电磁换向阀向双作用气缸供气,实现顶起机构的顶起和放下。整个装置结构紧凑、布局合理、维护简单、操作方便、移动灵活,并有故障保护、限位保护和紧急断电保护功能。

  2. Virtual water flows related to land use in an intensive agriculture in the Fergana Valley, Uzbekistan

    Science.gov (United States)

    Klipstein, A.; Schneider, K.; Breuer, L.; Frede, H. G.

    2009-04-01

    Due to low annual precipitation, agricultural production in Uzbekistan is depending on irrigation from the Syrdarya and Amudarya rivers to a great deal. One of the most important cash crops of the country is cotton. Current irrigation management leads to elevated groundwater levels, salinization of soils and to a degradation of soil and water resources. Through export of cotton and other crops, the problems related to water consumption and water management are transported beyond the producing country. The amount of water transported through production and export is referred to as virtual water. To distinguish between productive and unproductive partitioning of water flows, the terms green and blue water have been introduced. Information on virtual water flows due to crop production usually only exist on country level. To reduce uncertainties related to generalization, the effect of land management and environmental factors on the partitioning of water flows needs to be studied on smaller scales. The presented study analyzes water fluxes in an intensively used agricultural area in the Fergana Valley, Uzbekistan. The study aims to a) quantify crop specific water consumption in agricultural production under current management and b) analyze water use efficiency as subject to land use and irrigation management. Based on crop production, irrigation management and environmental conditions in the study area, virtual water flows will be calculated on the level of agricultural collectives (Water Users Associations). In a further step, the partitioning of green and blue water fluxes will be quantified. Alternative scenarios for improved water management will be analyzed in a model study.

  3. Human health risk assessment related to contaminated land: state of the art.

    Science.gov (United States)

    Swartjes, F A

    2015-08-01

    Exposure of humans to contaminants from contaminated land may result in many types of health damage ranging from relatively innocent symptoms such as skin eruption or nausea, on up to cancer or even death. Human health protection is generally considered as a major protection target. State-of-the-art possibilities and limitations of human health risk assessment tools are described in this paper. Human health risk assessment includes two different activities, i.e. the exposure assessment and the hazard assessment. The combination of these is called the risk characterization, which results in an appraisal of the contaminated land. Exposure assessment covers a smart combination of calculations, using exposure models, and measurements in contact media and body liquids and tissue (biomonitoring). Regarding the time frame represented by exposure estimates, biomonitoring generally relates to exposure history, measurements in contact media to actual exposures, while exposure calculations enable a focus on exposure in future situations. The hazard assessment, which is different for contaminants with or without a threshold for effects, results in a critical exposure value. Good human health risk assessment practice accounts for tiered approaches and multiple lines of evidence. Specific attention is given here to phenomena such as the time factor in human health risk assessment, suitability for the local situation, background exposure, combined exposure and harmonization of human health risk assessment tools.

  4. Calculation of odour emissions from aircraft engines at Copenhagen Airport.

    Science.gov (United States)

    Winther, Morten; Kousgaard, Uffe; Oxbøl, Arne

    2006-07-31

    In a new approach the odour emissions from aircraft engines at Copenhagen Airport are calculated using actual fuel flow and emission measurements (one main engine and one APU: Auxiliary Power Unit), odour panel results, engine specific data and aircraft operational data for seven busy days. The calculation principle assumes a linear relation between odour and HC emissions. Using a digitalisation of the aircraft movements in the airport area, the results are depicted on grid maps, clearly reflecting aircraft operational statistics as single flights or total activity during a whole day. The results clearly reflect the short-term temporal fluctuations of the emissions of odour (and exhaust gases). Aircraft operating at low engine thrust (taxiing, queuing and landing) have a total odour emission share of almost 98%, whereas the shares for the take off/climb out phases (2%) and APU usage (0.5%) are only marginal. In most hours of the day, the largest odour emissions occur, when the total amount of fuel burned during idle is high. However, significantly higher HC emissions for one specific engine cause considerable amounts of odour emissions during limited time periods. The experimentally derived odour emission factor of 57 OU/mg HC is within the range of 23 and 110 OU/mg HC used in other airport odour studies. The distribution of odour emission results between aircraft operational phases also correspond very well with the results for these other studies. The present study uses measurement data for a representative engine. However, the uncertainties become large when the experimental data is used to estimate the odour emissions for all aircraft engines. More experimental data is needed to increase inventory accuracy, and in terms of completeness it is recommended to make odour emission estimates also for engine start and the fuelling of aircraft at Copenhagen Airport in the future.

  5. Multispectral imaging of aircraft exhaust

    Science.gov (United States)

    Berkson, Emily E.; Messinger, David W.

    2016-05-01

    Aircraft pollutants emitted during the landing-takeoff (LTO) cycle have significant effects on the local air quality surrounding airports. There are currently no inexpensive, portable, and unobtrusive sensors to quantify the amount of pollutants emitted from aircraft engines throughout the LTO cycle or to monitor the spatial-temporal extent of the exhaust plume. We seek to thoroughly characterize the unburned hydrocarbon (UHC) emissions from jet engine plumes and to design a portable imaging system to remotely quantify the emitted UHCs and temporally track the distribution of the plume. This paper shows results from the radiometric modeling of a jet engine exhaust plume and describes a prototype long-wave infrared imaging system capable of meeting the above requirements. The plume was modeled with vegetation and sky backgrounds, and filters were selected to maximize the detectivity of the plume. Initial calculations yield a look-up chart, which relates the minimum amount of emitted UHCs required to detect the presence of a plume to the noise-equivalent radiance of a system. Future work will aim to deploy the prototype imaging system at the Greater Rochester International Airport to assess the applicability of the system on a national scale. This project will help monitor the local pollution surrounding airports and allow better-informed decision-making regarding emission caps and pollution bylaws.

  6. Achieving compliance with environmental health-related land use planning conditions in Hong Kong: perspectives from traditional motivation theories.

    Science.gov (United States)

    Man, Rita Li Yi

    2009-11-01

    Environmental health-related land use planning conditions can enhance the environment in Hong Kong. Previous research by others has shown, however, that a lack of compliance with planning conditions often occurs. And as no direct enforcement of planning conditions exists in Hong Kong, it is of interest to understand possible ways in which to increase the motivation of land developers and property owners to comply with planning conditions. The author looked at motivation from the perspective of three traditional motivation theories: Theory X, Theory Y, and incentive theory. While the majority of this article focuses on the enforcement and the legal tests in land use planning conditions, it also presents the results of the first study of the motivations behind Hong Kong land developers to comply with land use planning conditions.

  7. Studies of Physcomitrella patens reveal that ethylene-mediated submergence responses arose relatively early in land-plant evolution

    KAUST Repository

    Yasumura, Yuki

    2012-10-18

    Colonization of the land by multicellular green plants was a fundamental step in the evolution of life on earth. Land plants evolved from fresh-water aquatic algae, and the transition to a terrestrial environment required the acquisition of developmental plasticity appropriate to the conditions of water availability, ranging from drought to flood. Here we show that extant bryophytes exhibit submergence-induced developmental plasticity, suggesting that submergence responses evolved relatively early in the evolution of land plants. We also show that a major component of the bryophyte submergence response is controlled by the phytohormone ethylene, using a perception mechanism that has subsequently been conserved throughout the evolution of land plants. Thus a plant environmental response mechanism with major ecological and agricultural importance probably had its origins in the very earliest stages of the colonization of the land. © 2012 Blackwell Publishing Ltd.

  8. Commercial Aircraft Integrated Vehicle Health Management Study

    Science.gov (United States)

    Reveley, Mary S.; Briggs, Jeffrey L.; Evans, Joni K.; Jones, Sharon Monica; Kurtoglu, Tolga; Leone, Karen M.; Sandifer, Carl E.; Thomas, Megan A.

    2010-01-01

    Statistical data and literature from academia, industry, and other government agencies were reviewed and analyzed to establish requirements for fixture work in detection, diagnosis, prognosis, and mitigation for IVHM related hardware and software. Around 15 to 20 percent of commercial aircraft accidents between 1988 and 2003 involved inalftfnctions or failures of some aircraft system or component. Engine and landing gear failures/malfunctions dominate both accidents and incidents. The IVI vl Project research technologies were found to map to the Joint Planning and Development Office's National Research and Development Plan (RDP) as well as the Safety Working Group's National Aviation Safety Strategic. Plan (NASSP). Future directions in Aviation Technology as related to IVHlvl were identified by reviewing papers from three conferences across a five year time span. A total of twenty-one trend groups in propulsion, aeronautics and aircraft categories were compiled. Current and ftiture directions of IVHM related technologies were gathered and classified according to eight categories: measurement and inspection, sensors, sensor management, detection, component and subsystem monitoring, diagnosis, prognosis, and mitigation.

  9. Amphibious Aircraft

    Data.gov (United States)

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

  10. Aircraft Disinsection

    Science.gov (United States)

    Some countries may require aircraft coming from countries where certain insects or insect-borne diseases are present, such as malaria and Zika virus, to be treated with insecticide. Find out about regulation of pesticides for this treatment.

  11. A NASA study of the impact of technology on future multimission aircraft

    Science.gov (United States)

    Samuels, Jeffrey J.

    1992-01-01

    A conceptual aircraft design study was recently completed which compared three supersonic multimission tactical aircraft. The aircraft were evaluated in two technology timeframes and were sized with consistent methods and technology assumptions so that the aircraft could be compared in operational utility or cost analysis trends. The three aircraft are a carrier-based Fighter/Attack aircraft, a land-based Multirole Fighter, and a Short Takeoff/Vertical Landing (STOVL) aircraft. This paper describes the design study ground rules used and the aircraft designed. The aircraft descriptions include weights, dimensions and layout, design mission and maneuver performance, and fallout mission performance. The effect of changing technology and mission requirements on the STOVL aircraft and the impact of aircraft navalization are discussed. Also discussed are the effects on the STOVL aircraft of both Thrust/Weight required in hover and design mission radius.

  12. 47 CFR 90.423 - Operation on board aircraft.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Operation on board aircraft. 90.423 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Operating Requirements § 90.423 Operation on board aircraft. (a) Except... after September 14, 1973, under this part may be operated aboard aircraft for air-to-mobile, air-to-base...

  13. 36 CFR 13.450 - Prohibition of aircraft use.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Prohibition of aircraft use... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Subsistence § 13.450 Prohibition of aircraft use. (a) Notwithstanding the provisions 43 CFR 36.11(f) the use of aircraft for access to or from lands and waters within a...

  14. Rapid groundwater-related land subsidence in Yemen observed by multi-temporal InSAR

    KAUST Repository

    Abdullin, Ayrat

    2015-04-01

    Several basins in Yemen are suffering from a rapid drawdown of groundwater, which is the most important water source for agricultural irrigation, industry and domestic use. However, detailed geodetic measurements in the region have been lacking and the extent and magnitude of groundwater-related land subsidence has been poorly known. We used 13 ascending ALOS and 15 descending Envisat images to study land subsidence of several basins in Yemen, with a special focus on the Sana\\'a and Mabar basins. From multitemporal synthetic aperture radar interferometric analysis (persistent scatterers (PS) and small baseline subsets (SBAS)) we examined the spatio-temporal behavior of the subsidence induced by depletion of groundwater aquifer systems from November 2003 to February 2011. In the interferometric data processing, we carefully chose interferogram pairs to minimize spatial and temporal decorrelation, because of high subsidence rates and the type of land cover. Our results show that the spatial pattern of subsidence remained quite stable during the observation period in both the Sana\\'a and Mabar basins. In the Sana\\'a basin, the maximum subsidence rate exceeded 14 cm/year in the radar line-of-sight (LOS) direction between 2003 and 2008 in an agricultural area just north of Sana\\'a city, where water wells have been drying up according to the well data. The subsidence rate was lower in the urban areas, or approximately 1 cm/year, exhibiting annual variations. The main subsidence was found in the center and southern parts of the city, while deformation in the northern part is less obvious. For the Mabar basin, the subsidence rate exceeded 30 cm/year in the agricultural area north of the town of Mabar during 2007 - 2011. The southern part of the Mabar basin also experienced high subsidence rates, although somewhat lower than to the north. Excessive water pumping is the main cause of the ground subsidence and it has already led to extensive ground fracturing at the edge

  15. Distribution of carbon, nitrogen and phosphorus in coastal wetland soil related land use in the Modern Yellow River Delta

    Science.gov (United States)

    Yu, Junbao; Zhan, Chao; Li, Yunzhao; Zhou, Di; Fu, Yuqin; Chu, Xiaojing; Xing, Qinghui; Han, Guangxuan; Wang, Guangmei; Guan, Bo; Wang, Qing

    2016-11-01

    The delivery and distribution of nutrients in coastal wetland ecosystems is much related to the land use. The spatial variations of TOC, TN, NH4+-N, NO3--N and TP and associated soil salinity with depth in 9 kinds land uses in coastal zone of the modern Yellow River Delta (YRD) was evaluated based on monitoring data in field from 2009 to 2015. The results showed that the average contents of soil TOC, TN, NO3--N, NH4+-N and TP were 4.21 ± 2.40 g kg-1, 375.91 ± 213.44, 5.36 ± 9.59 and 7.20 ± 5.58 and 591.27 ± 91.16 mg kg-1, respectively. The high N and C contents were found in cropland in southern part and low values in natural wetland, while TP was relatively stable both in profiles and in different land uses. The land use, land formation age and salinity were important factors influencing distributions of TOC and N. Higher contents of TOC and N were observed in older formation age lands in whole study region, while the opposite regulation were found in new-born natural wetland, indicating that the anthropogenic activities could greatly alter the original distribution regulations of nutrients in coastal natural wetlands by changing the regional land use.

  16. Changes in Land Surface Water Dynamics since the 1990s and Relation to Population Pressure

    Science.gov (United States)

    Prigent, C.; Papa, F.; Aires, F.; Jimenez, C.; Rossow, W. B.; Matthews, E.

    2012-01-01

    We developed a remote sensing approach based on multi-satellite observations, which provides an unprecedented estimate of monthly distribution and area of land-surface open water over the whole globe. Results for 1993 to 2007 exhibit a large seasonal and inter-annual variability of the inundation extent with an overall decline in global average maximum inundated area of 6% during the fifteen-year period, primarily in tropical and subtropical South America and South Asia. The largest declines of open water are found where large increases in population have occurred over the last two decades, suggesting a global scale effect of human activities on continental surface freshwater: denser population can impact local hydrology by reducing freshwater extent, by draining marshes and wetlands, and by increasing water withdrawals. Citation: Prigent, C., F. Papa, F. Aires, C. Jimenez, W. B. Rossow, and E. Matthews (2012), Changes in land surface water dynamics since the 1990s and relation to population pressure, in section 4, insisting on the potential applications of the wetland dataset.

  17. Land use patterns and related carbon losses following deforestation in South America

    Science.gov (United States)

    De Sy, V.; Herold, M.; Achard, F.; Beuchle, R.; Clevers, J. G. P. W.; Lindquist, E.; Verchot, L.

    2015-12-01

    Land use change in South America, mainly deforestation, is a large source of anthropogenic CO2 emissions. Identifying and addressing the causes or drivers of anthropogenic forest change is considered crucial for global climate change mitigation. Few countries however, monitor deforestation drivers in a systematic manner. National-level quantitative spatially explicit information on drivers is often lacking. This study quantifies proximate drivers of deforestation and related carbon losses in South America based on remote sensing time series in a systematic, spatially explicit manner. Deforestation areas were derived from the 2010 global remote sensing survey of the Food and Agricultural Organisation Forest Resource Assessment. To assess proximate drivers, land use following deforestation was assigned by visual interpretation of high-resolution satellite imagery. To estimate gross carbon losses from deforestation, default Tier 1 biomass levels per country and eco-zone were used. Pasture was the dominant driver of forest area (71.2%) and related carbon loss (71.6%) in South America, followed by commercial cropland (14% and 12.1% respectively). Hotspots of deforestation due to pasture occurred in Northern Argentina, Western Paraguay, and along the arc of deforestation in Brazil where they gradually moved into higher biomass forests causing additional carbon losses. Deforestation driven by commercial cropland increased in time, with hotspots occurring in Brazil (Mato Grosso State), Northern Argentina, Eastern Paraguay and Central Bolivia. Infrastructure, such as urban expansion and roads, contributed little as proximate drivers of forest area loss (1.7%). Our findings contribute to the understanding of drivers of deforestation and related carbon losses in South America, and are comparable at the national, regional and continental level. In addition, they support the development of national REDD+ interventions and forest monitoring systems, and provide valuable input

  18. Attributing greenhouse gas emissions associated with land use and land use change to direct and indirect human and natural drivers: a modelling study to estimate their relative importance.

    Science.gov (United States)

    Hastings, Astley; Abdalla, Mohamed; Bell, Madeleine; Blagodatskiy, Sergey; Datta, Arindam; Dondini, Marta; Fitton, Nuala; Jones, Ed; Klumpp, Katja; Nemoto, Rie; Richards, Mark; Yeluripati, Jagadeesh; Smith, Pete

    2013-04-01

    Since humans cultivated crops, domesticated livestock and exploited woods and grasslands they have directly changed land use. In Europe, most of the landscapes are anthropogenically influenced. Each land use will have its carbon stock in the soil and vegetation that will depend on the geography, parent material of the soil, the climate and its land use history. For each land use and cover the soil carbon stock will reach a steady state where the rate of decomposition of the soil carbon is balanced by the organic material input each year. Each type of vegetation will reach a steady state depending on the length of its plants life cycle; for annual plants it is months, perennial grasslands it is years and for forest it is decades or centuries. In addition, the management of the crops, grasses or trees can be intensive, where the maximum vegetation is harvested or grazed, or extensive, when part of the plant material is left as a soil input. Net carbon flux will depend on the carbon balance between photosynthesis and respiration. Methane flux will mainly depend of the water content and redox potential of the soil and nitrous oxide emissions will depend of the type and amount of nitrogen input, pH and the relative timing of rainfall events, as well as the climatic conditions. In his study we have used site experiments to parameterize ecosystem models such as ECOSSE, DAYCENT, PASIM and DNDC on sites where there were more than one land use treatment to investigate the relative impact of human direct and indirect drivers compared to natural ones. Once the models have been parameterized the drivers to be investigated are systematically changed. The land uses investigated are grassland, forest, peatland and cropland. The direct drivers investigated are land use change (from cropland and grassland to bioenergy grasses, cropland to grassland and forest) and management change from intensive to extensive and vice versa. The management drivers investigated include tillage

  19. Land related grievances shape tropical forest-cover in areas affected by armed-conflict

    DEFF Research Database (Denmark)

    Nunez, Augusto Carlos Castro; Mertz, Ole; Buritica, Alexander

    2017-01-01

    Armed-conflicts often occur in tropical areas considered to be of high ‘conservation-value’, termed as such for their biodiversity or carbon-storage functions. Despite this important overlap, few studies have assessed how forest-biomass is affected by armed-conflicts. Thus, in this paper we develop...... a multinomial logit model to examine how outcomes of the interactions between carbon-storage, armed-conflict and deforestation rates are linked to social, institutional and economic factors. We use Colombia as a case study because of its protracted armed-conflict, high forest-cover, sustained deforestation...... a research gap by providing statistically sound evidence for associations between armed-conflicts and land-related grievances, which has rarely been demonstrated empirically. Our results also suggest that forest commons are associated with reduced armed-conflict, and simultaneously provide contributions...

  20. Mapping tsunami impacts on land cover and related ecosystem service supply in Phang Nga, Thailand

    Science.gov (United States)

    Kaiser, G.; Burkhard, B.; Römer, H.; Sangkaew, S.; Graterol, R.; Haitook, T.; Sterr, H.; Sakuna-Schwartz, D.

    2013-12-01

    The 2004 Indian Ocean tsunami caused damages to coastal ecosystems and thus affected the livelihoods of the coastal communities who depend on services provided by these ecosystems. The paper presents a case study on evaluating and mapping the spatial and temporal impacts of the tsunami on land use and land cover (LULC) and related ecosystem service supply in the Phang Nga province, Thailand. The method includes local stakeholder interviews, field investigations, remote-sensing techniques, and GIS. Results provide an ecosystem services matrix with capacity scores for 18 LULC classes and 17 ecosystem functions and services as well as pre-/post-tsunami and recovery maps indicating changes in the ecosystem service supply capacities in the study area. Local stakeholder interviews revealed that mangroves, casuarina forest, mixed beach forest, coral reefs, tidal inlets, as well as wetlands (peat swamp forest) have the highest capacity to supply ecosystem services, while e.g. plantations have a lower capacity. The remote-sensing based damage and recovery analysis showed a loss of the ecosystem service supply capacities in almost all LULC classes for most of the services due to the tsunami. A fast recovery of LULC and related ecosystem service supply capacities within one year could be observed for e.g. beaches, while mangroves or casuarina forest needed several years to recover. Applying multi-temporal mapping the spatial variations of recovery could be visualised. While some patches of coastal forest were fully recovered after 3 yr, other patches were still affected and thus had a reduced capacity to supply ecosystem services. The ecosystem services maps can be used to quantify ecological values and their spatial distribution in the framework of a tsunami risk assessment. Beyond that they are considered to be a useful tool for spatial analysis in coastal risk management in Phang Nga.

  1. Robust Control of an Ill-Conditioned Aircraft

    DEFF Research Database (Denmark)

    Breslin, S.G.; Tøffner-Clausen, S.; Grimble, M.J.

    1996-01-01

    A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point.......A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point....

  2. Robust Control of an Ill-Conditioned Aircraft

    DEFF Research Database (Denmark)

    Breslin, S.G.; Tøffner-Clausen, S.; Grimble, M.J.;

    1996-01-01

    A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point.......A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point....

  3. Comparison of impact forces, accelerations and ankle range of motion in surfing-related landing tasks.

    Science.gov (United States)

    Lundgren, Lina E; Tran, Tai T; Nimphius, Sophia; Raymond, Ellen; Secomb, Josh L; Farley, Oliver R L; Newton, Robert U; Sheppard, Jeremy M

    2016-01-01

    This study aimed to describe the impact forces, accelerations and ankle range of motion in five different landing tasks that are used in training and testing for competitive surfing athletes, to assist coaches in the prescription of landing task progression and monitoring training load. Eleven competitive surfing athletes aged 24 ± 7 years participated, and inertial motion sensors were fixed to the anterior aspect of the feet, mid-tibial shafts, sacrum and eighth thoracic vertebrae on these athletes. Three tasks were performed landing on force plates and two tasks in a modified gymnastics set-up used for land-based aerial training. Peak landing force, resultant peak acceleration and front and rear side ankle dorsiflexion ranges of motion during landing were determined. The peak acceleration was approximately 50% higher when performing aerial training using a mini-trampoline and landing on a soft-density foam board, compared to a similar landing off a 50 cm box. Furthermore, the ankle ranges of motion during the gymnastic type landings were significantly lower than the other landing types (P ≤ 0.05 and P ≤ 0.001), for front and rear sides, respectively. Conclusively, increased task complexity and specificity of the sport increased the tibial peak acceleration, indicating greater training load.

  4. Peat surface GHG fluxes related to peat hydrology in various tropical peat land uses

    Science.gov (United States)

    Jauhiainen, Jyrki; Silvennoinen, Hanna; Limin, Suwido; Vasander, Harri

    2010-05-01

    peat on tropical peat carbon dynamics is very difficult because of variations in environmental conditions (especially peat hydrology), peat and vegetation that are not collected systematically or reported adequately in studies. In this paper we (i.) compare the most important greenhouse gases, i.e. CO2, CH4, and N2O, related to peatland hydrology in typical land use types and peat drainage intensities, and (ii.) assess gaps existing in currently available GHG data collected from tropical peat in South-East Asia. Presented information is derived from our established GHG flux monitoring programs and reviewed values from literature. Land use types in GHG comparisons include selectively logged non-drained and drainage affected peat swamp forests, plantations, agricultural peat, and mismanaged abandoned peatlands. The results are discussed on basis of GHG dynamics controlling factors in various tropical peat land uses.

  5. Relating trends in land surface-air temperature difference to soil moisture and evapotranspiration

    Science.gov (United States)

    Veal, Karen; Taylor, Chris; Gallego-Elvira, Belen; Ghent, Darren; Harris, Phil; Remedios, John

    2016-04-01

    Soil water is central to both physical and biogeochemical processes within the Earth System. Drying of soils leads to evapotranspiration (ET) becoming limited or "water-stressed" and is accompanied by rises in land surface temperature (LST), land surface-air temperature difference (delta T), and sensible heat flux. Climate models predict sizable changes to the global water cycle but there is variation between models in the time scale of ET decay during dry spells. The e-stress project is developing novel satellite-derived diagnostics to assess the ability of Earth System Models (ESMs) to capture behaviour that is due to soil moisture controls on ET. Satellite records of LST now extend 15 years or more. MODIS Terra LST is available from 2000 to the present and the Along-Track Scanning Radiometer (ATSR) LST record runs from 1995 to 2012. This paper presents results from an investigation into the variability and trends in delta T during the MODIS Terra mission. We use MODIS Terra and MODIS Aqua LST and ESA GlobTemperature ATSR LST with 2m air temperatures from reanalyses to calculate trends in delta T and "water-stressed" area. We investigate the variability of delta T in relation to soil moisture (ESA CCI Passive Daily Soil Moisture), vegetation (MODIS Monthly Normalized Difference Vegetation Index) and precipitation (TRMM Multi-satellite Monthly Precipitation) and compare the temporal and spatial variability of delta T with model evaporation data (GLEAM). Delta T anomalies show significant negative correlations with soil moisture, in different seasons, in several regions across the planet. Global mean delta T anomaly is small (magnitude mostly less than 0.2 K) between July 2002 and July 2008 and decreases to a minimum in early 2010. The reduction in delta T anomaly coincides with an increase in soil moisture anomaly and NDVI anomaly suggesting an increase in evapotranspiration and latent heat flux with reduced sensible heat flux. In conclusion there have been

  6. Land subsidence and problems affecting land use at Edwards Air Force Base and vicinity, California, 1990

    Science.gov (United States)

    Blodgett, James C.; Williams, J. S.

    Land subsidence in Antelope Valley, which includes Edwards Air Force Base, was first reported in the 1950's; by 1967, about 200 square miles of Antelope Valley were affected by as much as 2 feet of subsidence. The purpose of the report is to present the results to date of recent studies done by the U.S. Geological Survey, in cooperation with the U.S. Department of the Air Force, to determine the cause and areal extent of land subsidence and surface deformation on Rogers Lakebed and vicinity, and the effects of surface deformation on runways used for aircraft landings at Edwards AFB in southern California. Because of the time-related effects of land subsidence, several years of data collection will be needed to establish subsidence trends and evaluate those factors causing land subsidence.

  7. Carbon balance impacts of land use changes related to the life cycle of Malaysian palm oil-derived biodiesel

    DEFF Research Database (Denmark)

    Hansen, Sune Balle; Olsen, Stig Irving; Ujang, Zaini

    2014-01-01

    to oil palm, in a life cycle perspective.LCA methodology is applied to existing land use change data. The assessment includes the issue of temporary carbon storage in the plantations. Through quantification of emissions from state forest reserve and rubber plantation conversions, the average Malaysian...... palm oil-related land use changes are calculated.The results show that there are high emissions associated with the conversion of Malaysian state forest reserve to oil palm, whereas the conversion of rubber leaves a less significant carbon debt when indirect land use change is not included. Looking......The area of oil palm plantations in Malaysia is expanding by approximately 0.14 million hectare per year, and with the increasing demand for palm oil worldwide, there is no sign of the expansions slowing down. This study aims to identify the greenhouse gas emissions associated with land conversion...

  8. Increased sugarcane water productivity in Brazil avoids land use change and related environmental impacts

    Science.gov (United States)

    Scarpare, F. V.; Galdos, M. V.; Kolln, O.; Gava, G.; Franco, H.; Trivelin, P.

    2012-12-01

    ratoon cane cycle. In order to demonstrate the potential effect of avoided land use change by increased productivity, we calculated the avoided GHG emissions related to land use change in a hypothetical fertirrigation project over a ten-year period (2010-2020). A conservative scenario for increased demand for sugarcane was selected, assuming a 20% increase in total production over the ten-year period. The current area under sugarcane in the municipality of Jaú is 42,500 ha. A 5,000 ha fertirrigation project, assuming the 40% increase in sugarcane productivity described above for the IN treatment, would avoid the conversion of 2,000 ha of other land uses in to sugarcane. Landsat data covering the region in the 2008/2009 crop year demonstrated that most conversion occurred over pasture areas (91%), with the remaining being converted from annual crops. Using IPCC biomass and soil carbon stock change factors and emission factors, the LUC-related emissions avoided by the fertirrigation project in the period were calculated as 53,199 Mg CO2 eq. A more comprehensive life cycle assessment of both the fertirrigation system and the reference case would be necessary to evaluate the actual GHG mitigation potential, but the preliminary results indicate that the increased productivity will bring environmental benefits under these conditions.

  9. The Relative Impact of Regional Scale Land Cover Change and Increasing CO2 over China

    Institute of Scientific and Technical Information of China (English)

    Mei ZHAO; Andrew J. PITMAN

    2005-01-01

    A series of 17-yr equilibrium simulations using the NCAR CCM3 (T42 resolution) were performed to investigate the regional scale impacts of land cover change and increasing CO2 over China. Simulations with natural and current land cover at CO2 levels of 280, 355,430, and 505 ppmv were conducted. Results show statistically significant changes in major climate fields (e.g. temperature and surface wind speed) ona 15-yr average following land cover change. We also found increases in the maximum temperature and in the diurnal temperature range due to land cover change. Increases in CO2 affect both the maximum and minimum temperature so that changes in the diurnal range are small. Both land cover change and CO2 change also impact the frequency distribution of precipitation with increasing CO2 tending to lead to more intense precipitation and land cover change leading to less intense precipitation-indeed, the impact of land cover change typically had the opposite effect versus the impacts of CO2. Our results provide support for the inclusion of future land cover change scenarios in long-term transitory climate modelling experiments of the 21st Century. Our results also support the inclusion of land surface models that can represent future land cover changes resulting from an ecological response to natural climate variability or increasing CO2. Overall, we show that land cover change can have a significant impact on the regional scale climate of China, and that regionally, this impact is of a similar magnitude to increases in CO2 of up to about 430 ppmv. This means that that the impact of land cover change must be accounted for in detection and attribution studies over China.

  10. 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

  11. 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

  12. Relation of water chemistry of the Edwards aquifer to hydrogeology and land use, San Antonio Region, Texas

    Science.gov (United States)

    Buszka, Paul M.

    1987-01-01

    Water-chemistry data from the Edwards aquifer for 1976-85, consisting of nearly 1,500 chemical analyses from 280 wells and 3 springs, were used to statistically evaluate relations among ground-water chemistry, hydrogeology, and land use. Five land uses associated with sampled wells were classified on the basis of published information and field surveys. Four major subareas of the aquifer were defined to reflect the relative susceptibility of ground water to contamination originating from human activities using hydrogeologic and tritium data.

  13. A method to determine land requirements relating to food consumption patterns

    NARCIS (Netherlands)

    Gerbens-Leenes, P.W.; Nonhebel, S.; Ivens, W.PMF

    2002-01-01

    Food production requires agricultural land. The area needed to feed a population depends on the one hand on production systems (e.g. yields per hectare), and on the other hand on the consumption (pattern) of this population. The amount of land available for food production is declining due to variou

  14. Prospects of fen restoration in relation to changing land use-An example from central Poland

    NARCIS (Netherlands)

    Klimkowska, Agata; Dzierża, Paulina; Grootjans, Ab P.; Kotowski, Wiktor; Diggelen, Rudy Van

    2010-01-01

    We carried out an eco-hydrological analysis to evaluate the most important effects of land use changes on the hydrological functioning of a fen system in Poland. We measured water levels (hydraulic heads) and water flow along a transect through the study area and also analysed land use changes using

  15. Prospects of fen restoration in relation to changing land use—An example from central Poland

    NARCIS (Netherlands)

    Klimkowska, A.; Dzierza, P.; Grootjans, A.P.; Kotowski, W.; Diggelen, R.

    2010-01-01

    We carried out an eco-hydrological analysis to evaluate the most important effects of land use changes on the hydrological functioning of a fen system in Poland. We measured water levels (hydraulic heads) and water flow along a transect through the study area and also analysed land use changes using

  16. Rubber Plantation Expansion Related Land Use Change along the Laos-China Border Region

    Directory of Open Access Journals (Sweden)

    Xiaona Liu

    2016-10-01

    Full Text Available Spatial-temporal changes of land use and land cover in Luang Namtha Province in northern part of Laos was analyzed using Landsat TM (Thematic Mapper/ETM+ (Enhanced Thematic Mapper images from 1990 to 2010 since the opening of the Boten border adjacent to China. The results showed that: (1 “forest land—cultivated land—grassland” was the primary landscape structure. Woodland was the major land cover type, while paddy field was the dominant land use type replaced by rubber plantation in 2010; (2 since the opening of the border crossings in 1994, the rate and intensity of land use change were accelerated and enhanced gradually, especially in the recent decade. Woodland decreased significantly, while shrubland, rubber plantation and swidden land increased obviously. Rubber plantation and swidden land showed the fastest growth derived from woodland and shrubland, indicating continuous human activities and slash-and-burn farming; and (3 during 1990–2010, swidden land was mainly located in northern mountainous areas with frequently increased changing spatial distribution in the recent decade. Rubber plantation was mainly distributed in the border region of China and Laos with the expansion from the border region into the non-frontier of Laos with Luang Namtha City as the center. Woodland reduction was so obvious along the Kunming-Bangkok highway.

  17. Land-Cover Phenologies and Their Relation to Climatic Variables in an Anthropogenically Impacted Mediterranean Coastal Area

    Directory of Open Access Journals (Sweden)

    Encarni I. Hernández

    2010-03-01

    Full Text Available Mediterranean coastal areas are experiencing rapid land cover change caused by human-induced land degradation and extreme climatic events. Vegetation index time series provide a useful way to monitor vegetation phenological variations. This study quantitatively describes Enhanced Vegetation Index (EVI temporal changes for Mediterranean land-covers from the perspective of vegetation phenology and its relation with climate. A time series from 2001 to 2007 of the MODIS Enhanced Vegetation Index 16-day composite (MOD13Q1 was analyzed to extract anomalies (by calculating z-scores and frequency domain components (by the Fourier Transform. Vegetation phenology analyses were developed for diverse land-covers for an area in south Alicante (Spain providing a useful way to analyze and understand the phenology associated to those land-covers. Time series of climatic variables were also analyzed through anomaly detection techniques and the Fourier Transform. Correlations between EVI time series and climatic variables were computed. Temperature, rainfall and radiation were significantly correlated with almost all land-cover classes for the harmonic analysis amplitude term. However, vegetation phenology was not correlated with climatic variables for the harmonic analysis phase term suggesting a delay between climatic variations and vegetation response.

  18. Relating Biodiversity and Landscape Spatial Patterning to Land Ownership Regimes in Northeastern Mexico

    Directory of Open Access Journals (Sweden)

    Miguel Alfonso. Ortega-Huerta

    2007-12-01

    Full Text Available Land legislation has changed dramatically in Mexico during recent years, putting greater emphasis on the integration of free market policies into local production methods. In a country like Mexico, replacement of traditional methods of production may result in the loss of practices that protect the natural environment. With the objective of providing baseline information for future conservation and/or land management programs, I evaluated how landscape patterning and the richness of bird and mammal species varied among current land ownership sizes and types, applying a stratified scheme that controlled for potential variation among different physiographic regions. I characterized landscape spatial patterning using the aggregation index, Shannon's Diversity Index, and the Modified Simpson's Evenness index, and I used the GARP modeling approach to estimate species richness within each land ownership regime. Particular attention was paid to variation among community-based vs. individually based ownership types. A notable finding with regard to parcel size is that there is a general pattern in which medium-to-large parcels contained greater percentages of natural vegetation; this relationship is less consistent for the largest parcels. Regarding land ownership types, community-based lands generally presented higher estimates of habitat conservation, i.e., a higher percentage of natural vegetation, higher aggregation, and more even distribution of land cover types, and a greater richness of bird and mammal species. These results suggest that attention should be paid to evaluating the importance of different types of land ownership in determining spatial patterns of biodiversity. Furthermore, these initial assessments, of how landscape structure and species richness varies across land ownership regimes, serve as reference points for future evaluations of change in landscape and biodiversity spatial patterns in Mexico.

  19. Relations among geology, physiography, land use, and stream habitat conditions in the Buffalo and Current River Systems, Missouri and Arkansas

    Science.gov (United States)

    Panfil, Maria S.; Jacobson, Robert B.

    2001-01-01

    This study investigated links between drainage-basin characteristics and stream habitat conditions in the Buffalo National River, Arkansas and the Ozark National Scenic Riverways, Missouri. It was designed as an associative study - the two parks were divided into their principle tributary drainage basins and then basin-scale and stream-habitat data sets were gathered and compared between them. Analyses explored the relative influence of different drainage-basin characteristics on stream habitat conditions. They also investigated whether a relation between land use and stream characteristics could be detected after accounting for geologic and physiographic differences among drainage basins. Data were collected for three spatial scales: tributary drainage basins, tributary stream reaches, and main-stem river segments of the Current and Buffalo Rivers. Tributary drainage-basin characteristics were inventoried using a Geographic Information System (GIS) and included aspects of drainage-basin physiography, geology, and land use. Reach-scale habitat surveys measured channel longitudinal and cross-sectional geometry, substrate particle size and embeddedness, and indicators of channel stability. Segment-scale aerial-photo based inventories measured gravel-bar area, an indicator of coarse sediment load, along main-stem rivers. Relations within and among data sets from each spatial scale were investigated using correlation analysis and multiple linear regression. Study basins encompassed physiographically distinct regions of the Ozarks. The Buffalo River system drains parts of the sandstone-dominated Boston Mountains and of the carbonate-dominated Springfield and Salem Plateaus. The Current River system is within the Salem Plateau. Analyses of drainage-basin variables highlighted the importance of these physiographic differences and demonstrated links among geology, physiography, and land-use patterns. Buffalo River tributaries have greater relief, steeper slopes, and more

  20. Functions on the Job in Relation to Data, People, and Things among Agricultural Students from Southern Land-Grant Universities

    Science.gov (United States)

    Zekeri, Andrew A.; Warren, Rueben

    2013-01-01

    This paper uses data from a sample of agriculture graduates from selected land-grant universities in the south to examine workers' functions on the job in relation to data, people, and things as described in the Dictionary of Occupational Titles. Tabular analysis was conducted using gamma and Pearson's correlation as measures of association.…

  1. Simulation of soil water regimes including pedotransfer functions and land-use related preferential flow

    NARCIS (Netherlands)

    Sonneveld, M.P.W.; Backx, M.A.H.M.; Bouma, J.

    2003-01-01

    Differences in land use history among taxonomically identical soils often result in different hydraulic properties, derived from either laboratory measurements or pedotransfer functions (PTFs). Additionally, flow mechanisms in sandy soils may also change through differences in water repellency

  2. Aircraft Noise and Quality of Life around Frankfurt Airport

    OpenAIRE

    Thomas Eikmann; Christin Peschel; Cara Kahl; Dirk Schreckenberg; Markus Meis

    2010-01-01

    In a survey of 2,312 residents living near Frankfurt Airport aircraft noise annoyance and disturbances as well as environmental (EQoL) and health-related quality of life (HQoL) were assessed and compared with data on exposure due to aircraft, road traffic, and railway noise. Results indicate higher noise annoyance than predicted from general exposure-response curves. Beside aircraft sound levels source-related attitudes were associated with reactions to aircraft noise. Furthermore, aircraft n...

  3. 14 CFR 399.43 - Treatment of leased aircraft.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Treatment of leased aircraft. 399.43... Treatment of leased aircraft. In determining the appropriate treatment of leased aircraft for ratemaking... leased aircraft value (determined on a constructive depreciated basis) in relation to net book value of...

  4. Factors Related to Spatial Patterns of Rural Land Fragmentation in Texas

    Science.gov (United States)

    Kjelland, Michael E.; Kreuter, Urs P.; Clendenin, George A.; Wilkins, R. Neal; Wu, X. Ben; Afanador, Edith Gonzalez; Grant, William E.

    2007-08-01

    Fragmentation of family-owned farms and ranches has been identified as the greatest single threat to wildlife habitat, water supply, and the long-term viability of agriculture in Texas. However, an integrative framework for insights into the pathways of land use change has been lacking. The specific objectives of the study are to test the hypotheses that the nonagricultural value (NAV) of rural land is a reliable indicator of trends in land fragmentation and that NAV in Texas is spatially correlated with population density, and to explore the idea that recent changes in property size patterns are better represented by a categorical model than by one that reflects incremental changes. We propose that the State-and-Transition model, developed to describe the dynamics of semi-arid ecosystems, provides an appropriate conceptual framework for characterizing categorical shifts in rural property patterns. Results suggest that changes in population density are spatially correlated with NAV and farm size, and that rural property size is spatially correlated with changes in NAV. With increasing NAV, the proportion of large properties tends to decrease while the area represented by small properties tends to increase. Although a correlation exists between NAV and population density, it is the trend in NAV that appears to be a stronger predictor of land fragmentation. The empirical relationships established herein, viewed within the conceptual framework of the State-and-Transition model, can provide a useful tool for evaluating land use policies for maintaining critical ecosystem services delivered from privately owned land in private land states, such as Texas.

  5. Dissolved organic matter release and retention in ultisols in relation to land use patterns.

    Science.gov (United States)

    Zhang, Qichun; Hou, Changping; Liang, Yingying; Feng, Ying

    2014-07-01

    The application of organic fertilizer to maintain soil fertility and crop yield has been practiced for thousands of years in China. This practice improves soil carbon sequestration, due to the high level of dissolved organic matter (DOM) in organic manure. In this study, batch equilibrium studies were conducted to examine the capacity of three ultisols from areas under different land use patterns to retain dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) extracted from rape cake and chicken manure. The results showed that the amount of DOM removed or released in solution by the soil was a linear function of the initial amount added to the soil-water system; therefore, analysis of sorption isotherms was best conducted using the initial mass isotherm IM method. The ultisol retained, on average, 19.9% of the total DOC and 41.7% of the total DON in solution, suggesting that ultisol has a relatively low DOC adsorption capacity. The ultisol from a bamboo forest was found to have a higher capacity than that from a pear orchard to retain DOC and DON. The adsorption affinities of DOM according to soil type were in the following order: bamboo forest (BF)>tea garden (TG)>pear orchard (PO). These results suggested that the continuous application of high doses of organic manure, particularly rape cake, may saturate the DOC adsorptive sites, thereby permitting increased leaching of DOC and the possibility of ground water contamination. Furthermore, we note that amorphous Fe and Al oxides play an important role in the adsorption capacity of both DOC and DON in ultisols.

  6. DAR, Land Reform-Related Agencies and the CARP: A Study of Government and Alternative Approaches to Land Acquisition and Distrib

    OpenAIRE

    Adriano, Lourdes S.

    1994-01-01

    This study examines the land acquisition and distribution process of the CARP by analyzing the nature and extent of participation of the various government agencies. Attempts are also made in identifying the areas where land reform can be hastened. While there are opportunities for change, the overall impact of these changes on land reform may not be as large in terms of area coverage, by mid-June 1998, the scheduled completion of CARP. Generally, there are many agencies involved in land refo...

  7. Hydrogen Storage for Aircraft Applications Overview

    Science.gov (United States)

    Colozza, Anthony J.; Kohout, Lisa (Technical Monitor)

    2002-01-01

    Advances in fuel cell technology have brought about their consideration as sources of power for aircraft. This power can be utilized to run aircraft systems or even provide propulsion power. One of the key obstacles to utilizing fuel cells on aircraft is the storage of hydrogen. An overview of the potential methods of hydrogen storage was compiled. This overview identifies various methods of hydrogen storage and points out their advantages and disadvantages relative to aircraft applications. Minimizing weight and volume are the key aspects to storing hydrogen within an aircraft. An analysis was performed to show how changes in certain parameters of a given storage system affect its mass and volume.

  8. A new method for large-scale assessment of change in ecosystem functioning in relation to land degradation

    Science.gov (United States)

    Horion, Stephanie; Ivits, Eva; Verzandvoort, Simone; Fensholt, Rasmus

    2017-04-01

    Ongoing pressures on European land are manifold with extreme climate events and non-sustainable use of land resources being amongst the most important drivers altering the functioning of the ecosystems. The protection and conservation of European natural capital is one of the key objectives of the 7th Environmental Action Plan (EAP). The EAP stipulates that European land must be managed in a sustainable way by 2020 and the UN Sustainable development goals define a Land Degradation Neutral world as one of the targets. This implies that land degradation (LD) assessment of European ecosystems must be performed repeatedly allowing for the assessment of the current state of LD as well as changes compared to a baseline adopted by the UNCCD for the objective of land degradation neutrality. However, scientifically robust methods are still lacking for large-scale assessment of LD and repeated consistent mapping of the state of terrestrial ecosystems. Historical land degradation assessments based on various methods exist, but methods are generally non-replicable or difficult to apply at continental scale (Allan et al. 2007). The current lack of research methods applicable at large spatial scales is notably caused by the non-robust definition of LD, the scarcity of field data on LD, as well as the complex inter-play of the processes driving LD (Vogt et al., 2011). Moreover, the link between LD and changes in land use (how land use changes relates to change in vegetation productivity and ecosystem functioning) is not straightforward. In this study we used the segmented trend method developed by Horion et al. (2016) for large-scale systematic assessment of hotspots of change in ecosystem functioning in relation to LD. This method alleviates shortcomings of widely used linear trend model that does not account for abrupt change, nor adequately captures the actual changes in ecosystem functioning (de Jong et al. 2013; Horion et al. 2016). Here we present a new methodology for

  9. Land management and development

    DEFF Research Database (Denmark)

    Enemark, Stig

    2006-01-01

    Land management is the process by which the resources of land are put into good effect. Land management encompasses all activities associated with the management of land that are required to achieve sustainable development. The concept of land includes properties and natural resources and thereby...... land related data. It is argued that development of such a model is important or even necessary for facilitating a holistic approach to the management of land as the key asset of any nation or jurisdiction....

  10. Review of factors affecting aircraft wet runway performance

    Science.gov (United States)

    Yager, T. J.

    1983-01-01

    Problems associated with aircraft operations on wet runways are discussed and major factors which influence tire/runway braking and cornering traction capability are identified including runway characteristics, tire hydroplaning, brake system anomalies, and pilot inputs. Research results from investigations conducted at the Langley Aircraft Landing Loads and Traction Facility and from tests with instrumented ground vehicles and aircraft are summarized to indicate the effects of different aircraft, tire, and runway parameters. Several promising means are described for improving tire/runway water drainage capability, brake system efficiency, and pilot training to help optimize aircraft traction performance on wet runways.

  11. Aircraft Wake Vortex Deformation in Turbulent Atmosphere

    OpenAIRE

    Hennemann, Ingo; Holzaepfel, Frank

    2007-01-01

    Large-scale distortion of aircraft wake vortices appears to play a crucial role for aircraft safety during approach and landing. Vortex distortion is investigated based on large eddy simulations of wake vortex evolution in a turbulent atmosphere. A vortex identification method is developed that can be adapted to the vortex scales of interest. Based on the identified vortex center tracks, a statistics of vortex curvature radii is established. This statistics constitutes the basis for understan...

  12. Ground-Water Quality and its Relation to Land Use on Oahu, Hawaii, 2000-01

    Science.gov (United States)

    Hunt, Charles D.

    2003-01-01

    Water quality in the main drinking-water source aquifers of Oahu was assessed by a one-time sampling of untreated ground water from 30 public-supply wells and 15 monitoring wells. The 384 square-mile study area, which includes urban Honolulu and large tracts of forested, agricultural, and suburban residential lands in central Oahu, accounts for 93 percent of the island's ground-water withdrawals. Organic compounds were detected in 73 percent of public-supply wells, but mostly at low concentrations below minimum reporting levels. Concentrations exceeded drinking-water standards in just a few cases: the solvent trichloroethene and the radionuclide radon-222 exceeded Federal standards in one public-supply well each, and the fumigants 1,2-dibromo-3-chloropropane (DBCP) and 1,2,3-trichloropropane (TCP) exceeded State standards in three public-supply wells each. Solvents, fumigants, trihalomethanes, and herbicides were prevalent (detected in more than 30 percent of samples) but gasoline components and insecticides were detected in few wells. Most water samples contained complex mixtures of organic compounds: multiple solvents, fumigants, or herbicides, and in some cases compounds from two or all three of these classes. Characteristic suites of chemicals were associated with particular land uses and geographic locales. Solvents were associated with central Oahu urban-military lands whereas fumigants, herbicides, and fertilizer nutrients were associated with central Oahu agricultural lands. Somewhat unexpectedly, little contamination was detected in Honolulu where urban density is highest, most likely as a consequence of sound land-use planning, favorable aquifer structure, and less intensive application of chemicals (or of less mobile chemicals) over recharge zones in comparison to agricultural areas. For the most part, organic and nutrient contamination appear to reflect decades-old releases and former land use. Most ground-water ages were decades old, with recharge

  13. Integrated assessment and the relation between land-use change and climate change

    Energy Technology Data Exchange (ETDEWEB)

    Dale, V.H.

    1994-10-07

    Integrated assessment is an approach that is useful in evaluating the consequences of global climate change. Understanding the consequences requires knowledge of the relationship between land-use change and climate change. Methodologies for assessing the contribution of land-use change to atmospheric CO{sub 2} concentrations are considered with reference to a particular case study area: south and southeast Asia. The use of models to evaluate the consequences of climate change on forests must also consider an assessment approach. Each of these points is discussed in the following four sections.

  14. Integrated Assessment and the Relation Between Land-Use Change and Climate Change

    Science.gov (United States)

    Dale, V. H.

    1994-10-07

    Integrated assessment is an approach that is useful in evaluating the consequences of global climate change. Understanding the consequences requires knowledge of the relationship between land-use change and climate change. Methodologies for assessing the contribution of land-use change to atmospheric CO{sub 2} concentrations are considered with reference to a particular case study area: south and southeast Asia. The use of models to evaluate the consequences of climate change on forests must also consider an assessment approach. Each of these points is discussed in the following four sections.

  15. Spectral emissivity measurements of land-surface materials and related radiative transfer simulations

    Science.gov (United States)

    Wan, Z.; Ng, D.; Dozier, J.

    1994-01-01

    Spectral radiance measurements have been made in the laboratory and in the field for deriving spectral emissivities of some land cover samples with a spectroradiometer and an auxiliary radiation source in the wavelength range 2.5-14.5 micrometers. A easy and quick four-step method (four steps to measure the sample and a diffuse reflecting plate surface under sunshine and shadowing conditions, respectively) has been used for simultaneous determination of surface temperature and emissivity. We emphasized in-situ measurements in combination with radiative transfer simulations, and an error analysis for basic assumptions in deriving spectral emissivity of land-surface samples from thermal infrared measurements.

  16. 航母中线电视监视系统的设计%Design of centerline television surveillance system for aircraft landing on carriers

    Institute of Scientific and Technical Information of China (English)

    赵建川; 邵俊峰; 王弟男; 陈长青; 王锐

    2012-01-01

    A centerline camera subsystem is designed for the mother-ship recovery television surveillance sys- tem. An Electron Multiplying Charge-coupled Device(EMCCD)-based Electrical-Optical(EO) imager is pro- posed according to the requirements for illumination principle, imaging contrast and resolution. The stability of a gyro-stabilized platform and the accuracy of a centerline camera are analyzed, and several imaging processing methods are discussed to solve the problems of position and inclination angles. It is found that the EO system based on Andor Ixon EMCCD with a diameter of 40 mm can fulfill the optical requirements for the centerline camera. The F/2 optical system based on a petzval show its MTF to be close to the diffraction limit. The sta- bility and accuracy status-quo gyro-stabilized platform is enough for the surveillance system. The centroid algo- rithm and edge operator imaging processing method are proposed to calculate the altitude, latitude and inclina- tion. The designed system is capable of performing surveillance with 24-hours a day, which is suitable for air- eraft landing on earriers.%研究设计了航母中线电视监视系统。依据照度、对比度及分辨率要求提出了一套基于电子倍增电荷耦合器件(EMCCD)的光电成像系统。分析了航母中线电视监视系统的舰载稳定平台的精度要求,并探讨了该系统可采用的图像处理算法。分析表明:采用主流的AndorIxonEMCCD并配合口径为40mm的光学系统可满足照度、对比度和分辨率的要求;采用Petzval形式初步设计的F/2光学系统,其光学传递函数接近衍射极限;而现有舰载稳定平台技术可以满足指向稳定的需要。最后,分析了形心算法、边缘算子算法在获取着舰机位置和姿态角的应用。该系统具有全天候工作能力,适用于航空母舰的着舰引导。

  17. Modeling Aircraft Emissions for Regional-scale Air Quality: Adapting a New Global Aircraft Emissions Database for the U.S

    Science.gov (United States)

    Arunachalam, S.; Baek, B. H.; Vennam, P. L.; Woody, M. C.; Omary, M.; Binkowski, F.; Fleming, G.

    2012-12-01

    Commercial aircraft emit substantial amounts of pollutants during their complete activity cycle that ranges from landing-and-takeoff (LTO) at airports to cruising in upper elevations of the atmosphere, and affect both air quality and climate. Since these emissions are not uniformly emitted over the earth, and have substantial temporal and spatial variability, it is vital to accurately evaluate and quantify the relative impacts of aviation emissions on ambient air quality. Regional-scale air quality modeling applications do not routinely include these aircraft emissions from all cycles. Federal Aviation Administration (FAA) has developed the Aviation Environmental Design Tool (AEDT), a software system that dynamically models aircraft performance in space and time to calculate fuel burn and emissions from gate-to-gate for all commercial aviation activity from all airports globally. To process in-flight aircraft emissions and to provide a realistic representation of these for treatment in grid-based air quality models, we have developed an interface processor called AEDTproc that accurately distributes full-flight chorded emissions in time and space to create gridded, hourly model-ready emissions input data. Unlike the traditional emissions modeling approach of treating aviation emissions as ground-level sources or processing emissions only from the LTO cycles in regional-scale air quality studies, AEDTproc distributes chorded inventories of aircraft emissions during LTO cycles and cruise activities into a time-variant 3-D gridded structure. We will present results of processed 2006 global emissions from AEDT over a continental U.S. modeling domain to support a national-scale air quality assessment of the incremental impacts of aircraft emissions on surface air quality. This includes about 13.6 million flights within the U.S. out of 31.2 million flights globally. We will focus on assessing spatio-temporal variability of these commercial aircraft emissions, and

  18. Implications of changes in tropical shifting cultivation intensification on land productivity and GHG-related biogeochemistry

    Science.gov (United States)

    Bustier, Bernard; Ngoy, Alfred; Pietsch, Stephan; Mosnier, Aline

    2017-04-01

    Traditional shifting cultivation used to be a sustainable type of land use for the subsistence of populations in tropical rainforests. The vast resource of moist tropical forests together with low population densities allowed for long fallow periods on sparsely distributed slash and burn parcels with large areas of untouched forest in between. Population growth and concomitant increase in land demand for subsistence as well as increasing infrastructure development for commercial forestry, cash crops and mining, however, altered the picture over recent decades. As a result, fallow periods were reduced due to lack of pristine land. In this study we use field data and modeling results from the Congo Basin to assess the impacts of reduced fallow periods on Carbon sequestration dynamics using a BGC model calibrated and validated with > 150 research plots distributed over the western Congo Basin and representing different management and land use histories. We find that the average carbon sequestration rate reduces over the number of cultivation cycles and that a reduction of the fallow from 10 years to 7 years reduce the average carbon sequestration between 13 and 21% and from 7 years to 4 years between 23 and 29% depending on soil fertility. Results will be discussed in the context of population growth and changes in environmetal conditions.

  19. Oxygen isotope variability in snow from western Dronning Maud Land, Antarctica and its relation to temperature

    NARCIS (Netherlands)

    Helsen, MM; Van de Wal, RSW; Van den Broeke, MR; Van As, D; Meijer, HAJ; Reijmer, CH

    2005-01-01

    This paper presents delta(18)O records from snow pits from four locations in Dronning Maud Land, Antarctica that contain at least four annual cycles. The aim of the study was to analyse in detail these records as well as the prevailing temperatures during accumulation in order to infer to what exten

  20. Land use patterns and related carbon losses following deforestation in South America

    NARCIS (Netherlands)

    Sy, De V.; Herold, M.; Achard, F.; Beuchle, R.; Clevers, J.G.P.W.; Lindquist, E.; Verchot, L.

    2015-01-01

    Land use change in South America, mainly deforestation, is a large source of anthropogenic CO2 emissions. Identifying and addressing the causes or drivers of anthropogenic forest change is considered crucial for global climate change mitigation. Few countries however, monitor deforesta

  1. Land use patterns and related carbon losses following deforestation in South America

    NARCIS (Netherlands)

    Sy, De V.; Herold, M.; Achard, F.; Beuchle, R.; Clevers, J.G.P.W.; Lindquist, E.; Verchot, L.

    2015-01-01

    Land use change in South America, mainly deforestation, is a large source of anthropogenic CO2 emissions. Identifying and addressing the causes or drivers of anthropogenic forest change is considered crucial for global climate change mitigation. Few countries however, monitor deforesta

  2. Parameters-related uncertainty in modeling sugar cane yield with an agro-Land Surface Model

    Science.gov (United States)

    Valade, A.; Ciais, P.; Vuichard, N.; Viovy, N.; Ruget, F.; Gabrielle, B.

    2012-12-01

    Agro-Land Surface Models (agro-LSM) have been developed from the coupling of specific crop models and large-scale generic vegetation models. They aim at accounting for the spatial distribution and variability of energy, water and carbon fluxes within soil-vegetation-atmosphere continuum with a particular emphasis on how crop phenology and agricultural management practice influence the turbulent fluxes exchanged with the atmosphere, and the underlying water and carbon pools. A part of the uncertainty in these models is related to the many parameters included in the models' equations. In this study, we quantify the parameter-based uncertainty in the simulation of sugar cane biomass production with the agro-LSM ORCHIDEE-STICS on a multi-regional approach with data from sites in Australia, La Reunion and Brazil. First, the main source of uncertainty for the output variables NPP, GPP, and sensible heat flux (SH) is determined through a screening of the main parameters of the model on a multi-site basis leading to the selection of a subset of most sensitive parameters causing most of the uncertainty. In a second step, a sensitivity analysis is carried out on the parameters selected from the screening analysis at a regional scale. For this, a Monte-Carlo sampling method associated with the calculation of Partial Ranked Correlation Coefficients is used. First, we quantify the sensitivity of the output variables to individual input parameters on a regional scale for two regions of intensive sugar cane cultivation in Australia and Brazil. Then, we quantify the overall uncertainty in the simulation's outputs propagated from the uncertainty in the input parameters. Seven parameters are identified by the screening procedure as driving most of the uncertainty in the agro-LSM ORCHIDEE-STICS model output at all sites. These parameters control photosynthesis (optimal temperature of photosynthesis, optimal carboxylation rate), radiation interception (extinction coefficient), root

  3. Conceptual design and optimization methodology for box wing aircraft

    OpenAIRE

    Jemitola, Paul Olugbeji

    2012-01-01

    A conceptual design optimization methodology was developed for a medium range box wing aircraft. A baseline conventional cantilever wing aircraft designed for the same mis- sion and payload was also optimized alongside a baseline box wing aircraft. An empirical formula for the mass estimation of the fore and aft wings of the box wing aircraft was derived by relating conventional cantilever wings to box wing aircraft wings. The results indicate that the fore and aft wings would ...

  4. Nuclear protein-coding genes support lungfish and not the coelacanth as the closest living relatives of land vertebrates.

    Science.gov (United States)

    Brinkmann, Henner; Venkatesh, Byrappa; Brenner, Sydney; Meyer, Axel

    2004-04-01

    The colonization of land by tetrapod ancestors is one of the major questions in the evolution of vertebrates. Despite intense molecular phylogenetic research on this problem during the last 15 years, there is, until now, no statistically supported answer to the question of whether coelacanths or lungfish are the closest living relatives of tetrapods. We determined DNA sequences of the nuclear-encoded recombination activating genes (Rag1 and Rag2) from all three major lungfish groups, the Australian Neoceratodis forsteri, the South American Lepidosiren paradoxa and the African lungfish Protopterus dolloi, and the Indonesian coelacanth Latimeria menadoensis. Phylogenetic analyses of both the single gene and the concatenated data sets of RAG1 and RAG2 found that the lungfishes are the closest living relatives of the land vertebrates. These results are supported by high bootstrap values, Bayesian posterior probabilities, and likelihood ratio tests.

  5. Trends in vegetation degradation in relation to land tenure, rainfall, and population changes in Peddie district, Eastern Cape, South Africa.

    Science.gov (United States)

    Kakembo, V

    2001-07-01

    Spatial and temporal variations in vegetation are examined in relation to land tenure, population increase, and rainfall variation in a part of Peddie district, Eastern Cape. Sequential aerial photographs between 1938 and 1988 are analyzed to determine trends in vegetation and population change in three different land-tenure units. The areal extent at each date of four distinct vegetation categories is determined using PC ARC/INFO GIS. Long-term annual rainfall trends for the area are analyzed and juxtaposed with vegetation changes. Extensive ground-truthing exercises are carried out to verify the present condition of vegetation condition in terms of cover and species composition. Differences in land-tenure systems are discerned as the dominant factor controlling variations in vegetation degradation. The study also reveals that neither population changes nor rainfall variations can explain the observed trends in vegetation degradation. Earlier injudicious land-use practices, sustained since the turn of the last century, may provide plausible explanations for the trends and present status of vegetation degradation in the area.

  6. 微小型垂直起降飞行器升力螺旋桨实验%Experimental study of static-thrust propeller for mini-vertical takeoff and landing (VTOL) aircraft

    Institute of Scientific and Technical Information of China (English)

    吴大卫; 李寒冰; 李书

    2011-01-01

    为提高微小型无人垂直起降飞行器的载重能力,针对其升力螺旋桨的悬停性能进行了系统性的参数对比实验.通过对实验数据进行分析对比和静推力状态螺旋桨片条理论计算,得出了各种几何参数对几何定距螺旋桨悬停性能影响的一系列结论.给出了此类螺旋桨的性能实验数据,结果表明较大的直径可显著改善悬停性能,同时存在最佳的中等偏低几何螺距、实度和平面形状,但后两个因素对此类螺旋桨的悬停性能影响较小.%Systematic experiments about static-thrust propellers' hovering performance with different geometrical parameters for unmanned mini-vertical takeoff and landing (VTOL) aircraft were made to enhance the lifting ability for more payloads. A series of conclusions about geometrical parameters' influence on hovering performance for propellers with constant pitch were summarized based on the test data and propeller strip theory suitable for static-thrust condition. This paper provides the test data of these propellers. The results show that larger diameter can improve hovering performance obviously, and there exist optimal lower medium pitch value, solidity and planform, but the latter two factors don't influence hovering performance obviously.

  7. 飞机进近着陆电磁环境建模与辐射分布分析%Modeling of electromagnetic environment and radiation distribution analysis for aircraft approaching and landing

    Institute of Scientific and Technical Information of China (English)

    王磊; 苏东林; 谢树果; 赵子华

    2012-01-01

    Electromagnetic field, terrain and obstacle are three vital elements which constitute electro- magnetic environment in aerodrome terminal. Because of their inhomogeneity in topology, physics and seman- teme, it is difficult to express the characteristic of the electromagnetic environment for aircraft approaching and landing with determined model. Based on the attribute of hierarchy and the coupling interrelation of those three elements, a multi-layer fused electromagnetic environment model frame for aerodrome terminal was put for- ward. In order to reduce the computation error induced by the non-regulation boundary variation of electromag- netic field, a combination of method of moment(MoM) and ray tracing methods was used to simulate the radi- ation pattern and wave propagation, and radiation intensity expression and distribution computation flow in ap- proaching and landing area were described. Simulation experiment of the radiation computation in approaching area based on one aerodrome dataset shows the validity of the modeling method.%机场终端区电磁、地形和地物在拓扑、物理和语义上的异构性导致进近着陆电磁环境构成机理复杂,很难用单尺度解析模型表征电磁环境的本质属性.在分析终端区多要素层次构成机理和关联耦合特征的基础上,提出一种多层融合的进近着陆电磁环境模型架构.综合采用矩量法和射线追踪法模拟台站辐射特性和地空电波传播模式,建立进近着陆区域电磁辐射强度量化表征与空间分布计算模型,有效降低了场边界特性不规则时空变化带来的电波预测误差.结合某机场地形和航向台数据,对终端区主航道和余隙航道的电磁辐射强度和覆盖范围进行计算和对比分析.仿真结果验证了本建模与分析方法的有效性.

  8. Changes in aquatic microbial responses to C-substrates with stream water and sediment quality related to land use pressures.

    Science.gov (United States)

    Stutter, Marc I; Cains, Jonathan

    2017-10-01

    The degradation of aquatic ecosystems by multiply-acting stressors is a key threat requiring new approaches to identify impairment processes and restoration targets. Heterotrophic respiration of C-substrates can be an integrative indicator of how aquatic ecosystems respond to pollution. We utilised sixteen C-substrates (simple metabolites to dissolved organic matter (DOM)) to characterise substrate induced respiration (SIR) for sediments from sixteen NE Scotland streams covering a range of land use-related pollution pressures. Pollution explanatory variables were as assessed from GIS-derived land cover areas, dissolved water chemistry (N, P, base cations and trace elements) and sediment trace metals (by aqua-regia digest). Large inter-site variation in dissolved and sediment chemical concentrations was strongly significantly correlated with land cover: dissolved N, Ca, Mg, K, Na positively with agriculture and urban, negatively with semi-natural land areas; sediment As, Ba, Co, Zn with agriculture, Cu, Pb, Zn with urban areas. Simple linear regression modelling was used to explore the influences across land cover, dissolved and sediment chemistry with C-substrate responses, both individually and using principal components-derived SIR 'fingerprints'. The data supported the hypothesis that pollution pressures altered water and sediment quality, in turn affecting sediment microbes and their respiration responses to a range of C-substrates, especially discriminating the DOM respiration. Since headwater DOM is a dominant pool of C driving ecosystem processes downstream then any loss of ability to utilise DOM should be further explored in terms of possible connections to pollution processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Soil fertility in relation to slope position and agricultural land use: a case study of Umbulo Catchment in southern Ethiopia.

    Science.gov (United States)

    Moges, Awdenegest; Holden, Nicholas M

    2008-11-01

    A study was conducted in southern Ethiopia to evaluate the nutrient status on smallholder farms with respect to land use class (garden, grassland, and outfield) and slope position (upper, middle, and lower). Soil physical and chemical properties were quantified using soil samples collected at two depths (0-15 and 15-30 cm). Available phosphorous was significantly different among the three land use classes. However, organic carbon and total nitrogen were lower in the outfield compared to the garden and grass land but not significantly different. The lower than expected nutrient status of the garden and grassland, which receive almost all available organic supplements, was attributed to the overall low availability of these inputs. Similarly, pH and cation exchange capacity were not significantly different among the different land use classes. However, the sum of the exchangeable cations was significantly higher in the garden compared to the outfields. Comparison at landscape level revealed that the sand fraction was significantly greater, whereas the silt fractions were significantly smaller, on the lower slopes relative to the middle slopes. Moreover, the organic carbon, total nitrogen, cation exchange capacity, Ca, and Mg values were significantly less on lower slopes than upper and middle slopes. Perhaps this is because of leaching and the effect of deposition of coarser sediments from the prevailing gully system. Overall, the fertility of the soil was adequate for supporting smallholder farming, but consideration must be given to reducing pressure on the land resources, addressing erosion problems, and providing a line of credit for purchasing inputs.

  10. Fire-related carbon emissions from land use transitions in southern Amazonia

    Science.gov (United States)

    DeFries, R. S.; Morton, D. C.; van der Werf, G. R.; Giglio, L.; Collatz, G. J.; Randerson, J. T.; Houghton, R. A.; Kasibhatla, P. K.; Shimabukuro, Y.

    2008-11-01

    Various land-use transitions in the tropics contribute to atmospheric carbon emissions, including forest conversion for small-scale farming, cattle ranching, and production of commodities such as soya and palm oil. These transitions involve fire as an effective and inexpensive means for clearing. We applied the DECAF (DEforestation CArbon Fluxes) model to Mato Grosso, Brazil to estimate fire emissions from various land-use transitions during 2001-2005. Fires associated with deforestation contributed 67 Tg C/yr (17 and 50 Tg C/yr from conversion to cropland and pasture, respectively), while conversion of savannas and existing cattle pasture to cropland contributed 17 Tg C/yr and pasture maintenance fires 6 Tg C/yr. Large clearings (>100 ha/yr) contributed 67% of emissions but comprised only 10% of deforestation events. From a policy perspective, results imply that intensification of agricultural production on already-cleared land and policies to discourage large clearings would reduce the major sources of emissions from fires in this region.

  11. Lift augmentation for highly swept wing aircraft

    Science.gov (United States)

    Rao, Dhanvada M. (Inventor)

    1993-01-01

    A pair of spaced slots, disposed on each side of an aircraft centerline and spaced well inboard of the wing leading edges, are provided in the wing upper surfaces and directed tangentially spanwise toward thin sharp leading wing edges of a highly swept, delta wing aircraft. The slots are individually connected through separate plenum chambers to separate compressed air tanks and serve, collectively, as a system for providing aircraft lift augmentation. A compressed air supply is tapped from the aircraft turbojet power plant. Suitable valves, under the control of the aircraft pilot, serve to selective provide jet blowing from the individual slots to provide spanwise sheets of jet air closely adjacent to the upper surfaces and across the aircraft wing span to thereby create artificial vortices whose suction generate additional lift on the aircraft. When desired, or found necessary, unequal or one-side wing blowing is employed to generate rolling moments for augmented lateral control. Trailing flaps are provided that may be deflected differentially, individually, or in unison, as needed for assistance in take-off or landing of the aircraft.

  12. Space shuttle recommendations based on aircraft maintenance experience

    Science.gov (United States)

    Spears, J. M.; Fox, C. L.

    1972-01-01

    Space shuttle design recommendations based on aircraft maintenance experience are developed. The recommendations are specifically applied to the landing gear system, nondestructive inspection techniques, hydraulic system design, materials and processes, and program support.

  13. Spatial relations between floodplain environments and land use - land cover of a large lowland tropical river valley: Pánuco basin, México.

    Science.gov (United States)

    Hudson, Paul F; Colditz, René R; Aguilar-Robledo, Miguel

    2006-09-01

    Large lowland river valleys include a variety of floodplain environments that represent opportunities and constraints for human activities. This study integrates extensive field observations and geomorphic data with analysis of satellite remote sensing data to examine spatial relations between land use/land cover (LULC) and floodplain environments in the lower Pánuco basin of eastern Mexico. The floodplain of the lower Pánuco basin was delineated by combining a digital elevation model with a satellite image of a large flood event. The LULC was classified by combining a hybrid classification strategy with image stratification, applied to 15-m-resolution ASTER data. A geomorphic classification of floodplain environments was performed using a dry-stage image (ASTER data) and a 1993 Landsat image acquired during a large flood event. Accuracy assessment was based on aerial photographs (1:38,000), global positioning satellite ground-truthing, and a Landsat 7ETM(+) image from 2000, which resulted in an overall accuracy of 82.9% and a KHAT of 79.8% for the LULC classification. The geomorphic classification yielded 83.5% overall accuracy, whereas the KHAT was 81.5%. LULC analysis was performed for the entire floodplain and individually within four valley segments. The analysis indicates that the study area is primarily utilized for grazing and farming. Agriculture is primarily associated with coarse-grained (sandy/silty) natural levee and point bar units close to the river channel, whereas cattle grazing occurs in distal and lower-lying reaches dominated by cohesive fine-grained (clayey) deposits, such as backswamps. In the Pánuco valley, wetlands and lakes occur within backswamp environments, whereas in the Moctezuma segments, wetlands and lakes are associated with relict channels. This study reveals considerable variation in LULC related to spatial differences in floodplain environments and illustrates the importance of considering older anthropogenic influences on the

  14. Heat shock protein expression in relation to reproductive cycle in land snails: Implications for survival.

    Science.gov (United States)

    Mizrahi, Tal; Heller, Joseph; Goldenberg, Shoshana; Arad, Zeev

    2011-10-01

    Land snails are subject to daily and seasonal variations in temperature and in water availability and use heat shock proteins (HSPs) as part of their survival strategy. We tested whether the reproductive cycle of land snails affects the endogenous levels of HSPs, and their involvement in the reproductive process. We examined HSP levels in the foot tissue of two Sphincterochila species, S. cariosa and S. zonata, before and after laying eggs, and analyzed the albumen gland (reproductive organ) of both species and eggs of S. cariosa for the presence and quantity of various HSPs. Our study shows reduction in the expression level of Hsp70 isoforms and Hsp90 in S. zonata foot and of Hsp74 in S. cariosa foot during the period preceding egg laying compared to the post-reproductive stage. Hsp70 isoforms and Hsp25 were highly expressed in both large albumen glands and in freshly laid eggs of S. cariosa, whereas large albumen glands of S. zonata expressed mainly Hsp70 isoforms. We conclude that a trade-off between survival and fertility is responsible for the expression level of HSPs in the foot tissue of Sphincterochila snails. Our study shows that HSPs are involved in the reproductive process. We propose that parental provision of HSPs may be part of a "be prepared" strategy of Sphincterochila snails, and that HSPs may play important roles in the survival strategy of land snails during the early life stages. Our observations also highlight the importance of the reproductive status in study of whole organisms, especially when assessing the HSP response to stress.

  15. Aircraft Electric Secondary Power

    Science.gov (United States)

    1983-01-01

    Technologies resulted to aircraft power systems and aircraft in which all secondary power is supplied electrically are discussed. A high-voltage dc power generating system for fighter aircraft, permanent magnet motors and generators for aircraft, lightweight transformers, and the installation of electric generators on turbine engines are among the topics discussed.

  16. Malaria entomological risk factors in relation to land cover in the Lower Caura River Basin, Venezuela

    Science.gov (United States)

    Rubio-Palis, Yasmin; Bevilacqua, Mariapia; Medina, Domingo Alberto; Moreno, Jorge Ernesto; Cárdenas, Lya; Sánchez, Víctor; Estrada, Yarys; Anaya, William; Martínez, Ángela

    2013-01-01

    To explore the effects of deforestation and resulting differences in vegetation and land cover on entomological parameters, such as anopheline species composition, abundance, biting rate, parity and entomological inoculation rate (EIR), three villages were selected in the Lower Caura River Basin, state of Bolívar, Venezuela. All-night mosquito collections were conducted between March 2008-January 2009 using CDC light traps and Mosquito Magnet(r) Liberty Plus. Human landing catches were performed between 06:00 pm-10:00 pm, when anophelines were most active. Four types of vegetation were identified. The Annual Parasite Index was not correlated with the type of vegetation. The least abundantly forested village had the highest anopheline abundance, biting rate and species diversity. Anopheles darlingi and Anopheles nuneztovari were the most abundant species and were collected in all three villages. Both species showed unique biting cycles. The more abundantly forested village of El Palmar reported the highest EIR. The results confirmed previous observations that the impacts of deforestation and resulting changes in vegetation cover on malaria transmission are complex and vary locally. PMID:23579803

  17. Using management to address vegetation stress related to land-use and climate change

    Science.gov (United States)

    Middleton, Beth A.; Boudell, Jere; Fisichelli, Nicholas

    2017-01-01

    While disturbances such as fire, cutting, and grazing can be an important part of the conservation of natural lands, some adjustments to management designed to mimic natural disturbance may be necessary with ongoing and projected climate change. Stressed vegetation that is incapable of regeneration will be difficult to maintain if adults are experiencing mortality, and/or if their early life-history stages depend on disturbance. A variety of active management strategies employing disturbance are suggested, including resisting, accommodating, or directing vegetation change by manipulating management intensity and frequency. Particularly if land-use change is the main cause of vegetation stress, amelioration of these problems using management may help vegetation resist change (e.g. strategic timing of water release if a water control structure is available). Managers could direct succession by using management to push vegetation toward a new state. Despite the historical effects of management, some vegetation change will not be controllable as climates shift, and managers may have to accept some of these changes. Nevertheless, proactive measures may help managers achieve important conservation goals in the future.

  18. 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.

  19. Control strategies for aircraft airframe noise reduction

    Institute of Scientific and Technical Information of China (English)

    Li Yong; Wang Xunnian; Zhang Dejiu

    2013-01-01

    With the development of low-noise aircraft engine,airframe noise now represents a major noise source during the commercial aircraft's approach to landing phase.Noise control efforts have therefore been extensively focused on the airframe noise problems in order to further reduce aircraft overall noise.In this review,various control methods explored in the last decades for noise reduction on airframe components including high-lift devices and landing gears are summarized.We introduce recent major achievements in airframe noise reduction with passive control methods such as fairings,deceleration plates,splitter plates,acoustic liners,slat cove cover and side-edge replacements,and then discuss the potential and control mechanism of some promising active flow control strategies for airframe noise reduction,such as plasma technique and air blowing/suction devices.Based on the knowledge gained throughout the extensively noise control testing,a few design concepts on the landing gear,high-lift devices and whole aircraft are provided for advanced aircraft low-noise design.Finally,discussions and suggestions are given for future research on airframe noise reduction.

  20. Low Noise Aircraft Selection Based on Improved Grey Relational Analysis of B-Mode%基于改进灰色B型关联度的低噪声飞机选型

    Institute of Scientific and Technical Information of China (English)

    李东亚; 胡荣; 江超; 战绪仁

    2015-01-01

    为有效缓解飞机噪声的影响,选择出噪声值更小的机型,针对国内某机场噪声监测数据特点,选用兼具相近性与相似性的灰色B型关联分析法对该机场一个月内同一航班六种机型噪声监测数据进行分析.根据研究问题需要,设计无量纲化处理方法,优化噪声监测数据权重,改进灰色B型关联度方法,计算各机型噪声数据与最优数据的关联度,优选出满足条件的低噪声机型.结果表明,改进后灰色B型关联度方法适用于低噪声飞机选型问题,分析结果符合实际,其中B733机型最能满足该机场低噪声的条件.%To alleviate the influence of aircraft noise effectively and choose the lower noise aircraft types, the noise monitoring data of six kinds of aircrafts for the same flight at a domestic airport were analyzed using the grey relational analysis of B-mode which has both proximity and similarity. In this analysis, a dimensionless processing method was designed to optimize the weight of the noise monitoring data and improve the grey relational analysis of B-mode. The correlations between the aircraft noise data of different type of aircrafts and the optimal noise data were calculated and the low noise aircraft type was selected. The results show that the improved grey relational analysis of B-mode is suitable for the selection of low noise aircraft, and the analysis results are consistent with the actual data. In addition, the B733 aircraft type is the best in satisfying the condition of low noise at the airport.

  1. Development of Longitudinal Equivalent System Models for Selected U.S. Navy Tactical Aircraft

    Science.gov (United States)

    1981-08-01

    revaraa side II nacaaaary and Identlly by block number) Aircraft Longitudinal Flying Qualities Equivalent Systems Frequency Response Matching...is a twin turbofan powered, land and carrier based, subsonic, anti- submarine warfare aircraft . Longitudinal control is accomplished via a...based, supersonic fighter aircraft . Longitudinal control is accomplished via an irreversible mechanical flight control system which transmits

  2. Mechanical demand and multijoint control during landing depend on orientation of the body segments relative to the reaction force.

    Science.gov (United States)

    McNitt-Gray, J L; Hester, D M; Mathiyakom, W; Munkasy, B A

    2001-11-01

    The purpose of this study was to determine how diverse momentum conditions and anatomical orientation at contact influences mechanical loading and multijoint control of the reaction force during landings. Male collegiate gymnasts (n=6) performed competition style landings (n=3) of drop jumps, front saltos, and back saltos from a platform (0.72 m) onto landing mats (0.12 m). Kinematics (200 fps), reaction forces (800 Hz) and muscle activation patterns (surface EMG, 1600 Hz) of seven lower extremity muscles were collected simultaneously. Between-task differences in segment orientation relative to the reaction force contributed to significant between-task differences in knee and hip net joint moments (NJM) during the impact phase. During the stabilization phase, ankle, knee, and hip NJMs acted to control joint flexion. Between-task differences in muscle activation patterns indicated that gymnasts scaled biarticular muscle activation to accommodate for between-task differences in NJM after contact. Activation of muscles on both sides of the joint suggests that impedance like control was used to stabilize the joints and satisfy the mechanical demand imposed on the lower extremity. Between-subject differences in the set of muscles used to control total body center of mass (TBCM) trajectory and achieve lower extremity NJMs suggests that control of multijoint movements involving impact needs to incorporate mechanical objectives at both the total body and local level. The functional consequences of such a control structure may prove to be an asset to gymnasts, particularly when required to perform a variety of landing tasks under a variety of environmental constraints.

  3. Job satisfaction among aircraft baggage handlers and their exposure to risk factors for work-related musculoskeletal disorders: A case study.

    Science.gov (United States)

    Bulduk, Sıdıka; Bulduk, Emre Özgür; Güler, Alpaslan

    2017-01-01

    Work-related musculoskeletal disorders (WMSDs) cause pain and economic loss. Risk of WMSDs is affected by job satisfaction as a psychosocial factor. The aim of this study was to investigate job satisfaction among aircraft baggage handlers and their exposure to work-related musculoskeletal disorder risk factors. Two data collection tools addressing risk levels (Quick Exposure Check) and psychosocial factors (Job Satisfaction Survey) were answered by 399 male baggage handlers employed in Esenboga International Airport in Ankara, Turkey. Risk exposure scores for WMSDs among baggage handlers were 27±3.4 (high) for the back (static), 42±7.2 (very high) for the back (moving), 42±6.1 (very high) for the shoulder/arm, 44±1.9 (very high) for the wrist/hand, and 13±5.1(high) for the neck. The average job satisfaction levels of the majority was either low (4.2250±1.10184) or moderate (3.1019±0.93352). In addition, low and moderate job satisfaction was significantly associated with higher WMSD risk levels among baggage handlers. Increased WMSD risk levels among baggage handlers are associated with low and moderate job satisfaction, suggesting that it is mandatory to perform intervention methods in this occupation.

  4. Exposure-effect relations between aircraft and road traffic noise exposure at school and reading comprehension: the RANCH project.

    NARCIS (Netherlands)

    Clark, Charlotte; Martin, Rocio; Kempen, Elise van; Alfred, Tamuno; Head, Jenny; Davies, Hugh W; Haines, Mary M; Lopez Barrio, Isabel; Matheson, Mark; Stansfeld, Stephen A

    2006-01-01

    Transport noise is an increasingly prominent feature of the urban environment, making noise pollution an important environmental public health issue. This paper reports on the 2001-2003 RANCH project, the first cross-national epidemiologic study known to examine exposure-effect relations between

  5. Exposure-effect relations between aircraft and road traffic noise exposure at school and reading comprehension: the RANCH project.

    NARCIS (Netherlands)

    Clark, Charlotte; Martin, Rocio; Kempen, Elise van; Alfred, Tamuno; Head, Jenny; Davies, Hugh W; Haines, Mary M; Lopez Barrio, Isabel; Matheson, Mark; Stansfeld, Stephen A

    2006-01-01

    Transport noise is an increasingly prominent feature of the urban environment, making noise pollution an important environmental public health issue. This paper reports on the 2001-2003 RANCH project, the first cross-national epidemiologic study known to examine exposure-effect relations between air

  6. The Application of mu Analysis and Synthesis to the Control of an ASTOVL Aircraft

    DEFF Research Database (Denmark)

    Tøffner-Clausen, S.; Andersen, Palle; Breslin, S.G.

    1995-01-01

    A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point.......A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point....

  7. The Application of mu Analysis and Synthesis to the Control of an ASTOVL Aircraft

    DEFF Research Database (Denmark)

    Tøffner-Clausen, S.; Andersen, Palle; Breslin, S.G.;

    1995-01-01

    A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point.......A robust controller is designed for a linear model of an Advanced Short Take-Off and Vertical Landing (ASTOVL) aircraft at one operating point....

  8. Changes in streamflow characteristics in Wisconsin as related to precipitation and land use

    Science.gov (United States)

    Gebert, Warren A.; Garn, Herbert S.; Rose, William J.

    2016-01-19

    Streamflow characteristics were determined for 15 longterm streamflow-gaging stations for the periods 1915–2008, 1915–68, and 1969–2008 to identify trends. Stations selected represent flow characteristics for the major river basins in Wisconsin. Trends were statistically significant at the 95 percent confidence level at 13 of the 15 streamflow-gaging stations for various streamflow characteristics for 1915–2008. Most trends indicated increases in low flows for streams with agriculture as the dominant land use. The three most important findings are: increases in low flows and average flows in agricultural watersheds, decreases in flood peak discharge for many streams in both agricultural and forested watersheds, and climatic change occurred with increasing annual precipitation and changes in monthly occurrence of precipitation. When the 1915–68 period is compared to the 1969–2008 period, the annual 7-day low flow increased an average of 60 percent for nine streams in agricultural areas as compared to a 15 percent increase for the five forested streams. Average annual flow for the same periods increased 23 percent for the agriculture streams and 0.6 percent for the forested streams. The annual flood peak discharge for the same periods decreased 15 percent for agriculture streams and 8 percent for forested streams. The largest increase in the annual 7-day low flow was 117 percent, the largest increase in annual average flow was 41 percent, and the largest decrease in annual peak discharge was 51 percent. The trends in streamflow characteristics affect frequency characteristics, which are used for a variety of design and compliance purposes. The frequencies for the 1969–2008 period were compared to frequencies for the 1915–68 period. The 7-day, 10-year (Q7, 10) low flow increased 91 percent for nine agricultural streams, while the five forested streams had an increase of 18 percent. The 100-year flood peak discharge decreased an average of 15 percent

  9. Land Disturbance Associated with Oil and Gas Development and Effects of Development-Related Land Disturbance on Dissolved-Solids Loads in Streams in the Upper Colorado River Basin, 1991, 2007, and 2025

    Science.gov (United States)

    Buto, Susan G.; Kenney, Terry A.; Gerner, Steven J.

    2010-01-01

    Oil and gas resource development in the Upper Colorado River Basin (UCRB) has increased substantially since the year 2000. The UCRB encompasses several significant oil and gas producing areas that have the potential for continued oil and gas resource development. Land disturbance associated with oil and gas resource development is caused by activities related to constructing drill pads to contain drilling and well maintenance equipment and roads to access the drill pad. Land disturbed by oil and gas development has the potential to cause increased erosion, stream degradation, habitat fragmentation and alteration, and increase public use of areas that may be environmentally sensitive. Land disturbance resulting from oil and gas resource development has not been monitored and mapped on a regional scale in the UCRB. However, information on the location and age of oil and gas wells in the UCRB is available. These data combined with geographic data analysis and modeling techniques were used to estimate the total area of disturbed land associated with oil and gas resource development in 1991 and in 2007 in the UCRB. Additional information about anticipated oil and gas development in the UCRB was used to project land disturbance to the year 2025. Results of the analysis indicate that approximately 117,500 acres (183 mi2) of total land disturbance was associated with drill pads and related roads in the UCRB in 1991. The estimated area of disturbed land associated with oil and gas development increased 53 percent to 179,400 acres (280 mi2) in 2007. Projecting oil and gas development through 2025 results in a potential near doubling of the land surface disturbance to approximately 319,300 acres (500 mi2). Estimated land disturbance for 1991 and 2007 were input to a contaminant transport model developed for the UCRB to assess the statistical significance of energy-related land disturbance to contributing dissolved solids to basin streams. The statistical assessment was an

  10. Relative importance of time, land use and lithology on determining aquifer-scale denitrification

    Science.gov (United States)

    Kolbe, Tamara; de Dreuzy, Jean-Raynald; Abbott, Benjamin W.; Marçais, Jean; Babey, Tristan; Thomas, Zahra; Peiffer, Stefan; Aquilina, Luc; Labasque, Thierry; Laverman, Anniet; Fleckenstein, Jan; Boulvais, Philippe; Pinay, Gilles

    2017-04-01

    Unconfined shallow aquifers are commonly contaminated by nitrate in agricultural regions, because of excess fertilizer application over the last decades. Watershed studies have indicated that 1) changes in agricultural practices have caused changes in nitrate input over time, 2) denitrification occurs in localized hotspots within the aquifer, and 3) heterogeneous groundwater flow circulation has led to strong nitrate gradients in aquifers that are not yet well understood. In this study we investigated the respective influence of land use, groundwater transit time distribution, and hotspot distribution on groundwater denitrification with a particular interest on how a detailed understanding of transit time distributions could be used to upscale the point denitrification measurements to the aquifer-scale. We measured CFC-based groundwater age, oxygen, nitrate, and dinitrogen gas excess in 16 agricultural wells of an unconfined crystalline aquifer in Brittany, France. Groundwater age data was used to calibrate a mechanistic groundwater flow model of the study site. Historical nitrate inputs were reconstructed by using measured nitrate concentrations, dinitrogen gas excess and transit time distributions of the wells. Field data showed large differences in denitrification activity among wells, strongly associated with differences in transit time distribution. This suggests that knowing groundwater flow dynamics and consequent transit time distributions at the catchment-scale could be used to estimate the overall denitrification capacity of agricultural aquifers.

  11. Changes in the Floating Plastic Pollution of the Mediterranean Sea in Relation to the Distance to Land.

    Science.gov (United States)

    Pedrotti, Maria Luiza; Petit, Stéphanie; Elineau, Amanda; Bruzaud, Stéphane; Crebassa, Jean-Claude; Dumontet, Bruno; Martí, Elisa; Gorsky, Gabriel; Cózar, Andrés

    2016-01-01

    The composition, size distribution, and abundance of floating plastic debris in surface waters of the Mediterranean Sea were analyzed in relation to distance to land. We combined data from previously published reports with an intensive sampling in inshore waters of the Northwestern Mediterranean. The highest plastic concentrations were found in regions distant from from land as well as in the first kilometer adjacent to the coastline. In this nearshore water strip, plastic concentrations were significantly correlated with the nearness to a coastal human population, with local areas close to large human settlements showing hundreds of thousands of plastic pieces per km2. The ratio of plastic to plankton abundance reached particularly high values for the coastal surface waters. Polyethylene, polypropylene and polyamides were the predominant plastic polymers at all distances from coast (86 to 97% of total items), although the diversity of polymers was higher in the 1-km coastal water strip due to a higher frequency of polystyrene or polyacrylic fibers. The plastic size distributions showed a gradual increase in abundance toward small sizes indicating an efficient removal of small plastics from the surface. Nevertheless, the relative abundance of small fragments (plastic debris in areas closest to Mediterranean coast. The presence of a high concentration of plastic including tiny plastic items could have significant environmental, health and economic impacts.

  12. Stable isotope composition of land snail body water and its relation to environmental waters and shell carbonate

    Science.gov (United States)

    Goodfriend, Glenn A.; Magaritz, Mordeckai; Gat, Joel R.

    1989-12-01

    Day-to-day and within-day (diel) variations in δD and δ18O of the body water of the land snail, Theba pisana, were studied at a site in the southern coastal plain of Israel. Three phases of variation, which relate to isotopic changes in atmospheric water vapor, were distinguished: 1) on rain days, snail water becomes isotopically depleted approximately in the direction of the rain isotope values, but always less depleted in D as is atmospheric water vapor; 2) during the 1-3 days following a rain, the snail water becomes isotopically enriched along a line with slope persists until the next rain event. The isotopic variations can be explained by isotopic equilibration with atmospheric water vapor and/or uptake of dew derived therefrom. During the winter, when the snails are active, there is only very minor enrichment in 18O relative to equilibrium with water vapor or dew, apparently as a result of metabolic activity. But this enrichment becomes pronounced after long periods of inactivity. Within-day variation in body water isotopic composition is minor on non-rain days. Shell carbonate is enriched in 18O by ca. 1-2%. relative to equilibrium with body water. In most regions, the isotopic composition of atmospheric water vapor (or dew) is a direct function of that of rain. Because the isotopic composition of snail body water is related to that of atmospheric water vapor and the isotopic composition of shell carbonate in turn is related to that of body water, land snail shell carbonate 18O should provide a reliable indication of rainfall 18O. However, local environmental conditions and the ecological properties of the snail species must be taken into account.

  13. Cycle Counting Methods of the Aircraft Engine

    Science.gov (United States)

    Fedorchenko, Dmitrii G.; Novikov, Dmitrii K.

    2016-01-01

    The concept of condition-based gas turbine-powered aircraft operation is realized all over the world, which implementation requires knowledge of the end-of-life information related to components of aircraft engines in service. This research proposes an algorithm for estimating the equivalent cyclical running hours. This article provides analysis…

  14. Temperature of aircraft cargo flame exposure during accidents involving fuel spills

    Energy Technology Data Exchange (ETDEWEB)

    Mansfield, J.A.

    1993-01-01

    This report describes an evaluation of flame exposure temperatures of weapons contained in alert (parked) bombers due to accidents that involve aircraft fuel fires. The evaluation includes two types of accident, collisions into an alert aircraft by an aircraft that is on landing or take-off, and engine start accidents. Both the B-1B and B-52 alert aircraft are included in the evaluation.

  15. 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

  16. Optics in aircraft engines

    Science.gov (United States)

    Vachon, James; Malhotra, Subhash

    The authors describe optical IR&D (independent research and development) programs designed to demonstrate and evaluate optical technologies for incorporation into next-generation military and commercial aircraft engines. Using a comprehensive demonstration program to validate this technology in an on-engine environment, problems encountered can be resolved early and risk can be minimized. In addition to specific activities related to the optics demonstration on the fighter engine, there are other optical programs underway, including a solenoid control system, a light off detection system, and an optical communication link. Research is also underway in simplifying opto-electronics and exploiting multiplexing to further reduce cost and weight.

  17. 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.

  18. Quantifying the relative importance of greenhouse gas emissions from current and future savanna land use change across northern Australia

    Science.gov (United States)

    Bristow, Mila; Hutley, Lindsay B.; Beringer, Jason; Livesley, Stephen J.; Edwards, Andrew C.; Arndt, Stefan K.

    2016-11-01

    The clearing and burning of tropical savanna leads to globally significant emissions of greenhouse gases (GHGs); however there is large uncertainty relating to the magnitude of this flux. Australia's tropical savannas occupy the northern quarter of the continent, a region of increasing interest for further exploitation of land and water resources. Land use decisions across this vast biome have the potential to influence the national greenhouse gas budget. To better quantify emissions from savanna deforestation and investigate the impact of deforestation on national GHG emissions, we undertook a paired site measurement campaign where emissions were quantified from two tropical savanna woodland sites; one that was deforested and prepared for agricultural land use and a second analogue site that remained uncleared for the duration of a 22-month campaign. At both sites, net ecosystem exchange of CO2 was measured using the eddy covariance method. Observations at the deforested site were continuous before, during and after the clearing event, providing high-resolution data that tracked CO2 emissions through nine phases of land use change. At the deforested site, post-clearing debris was allowed to cure for 6 months and was subsequently burnt, followed by extensive soil preparation for cropping. During the debris burning, fluxes of CO2 as measured by the eddy covariance tower were excluded. For this phase, emissions were estimated by quantifying on-site biomass prior to deforestation and applying savanna-specific emission factors to estimate a fire-derived GHG emission that included both CO2 and non-CO2 gases. The total fuel mass that was consumed during the debris burning was 40.9 Mg C ha-1 and included above- and below-ground woody biomass, course woody debris, twigs, leaf litter and C4 grass fuels. Emissions from the burning were added to the net CO2 fluxes as measured by the eddy covariance tower for other post-deforestation phases to provide a total GHG emission from

  19. Relation between surface topography and sea-salt snow chemistry from Princess Elizabeth Land, East Antarctica

    Directory of Open Access Journals (Sweden)

    K. Mahalinganathan

    2012-04-01

    Full Text Available Previous studies on Antarctic snow have established an unambiguous correlation between variability of sea-salt records and site specific features like elevation and proximity to the sea. On the other hand, variations of Cl/Na+ ratios in snow have been attributed to the reaction mechanisms involving atmospheric acids. In the present study, the annual records of Na+, Cl and SO42− were investigated using snow cores along a 180 km coast to inland transect in Princess Elizabeth Land, East Antarctica. Exceptionally high Na+ concentrations and large variations in Cl/Na+ ratios were observed up to 50 km (∼1100 m elevation of the transect. The steepest slope in the entire transect (49.3 m km−1 was between 20 and 30 km and the sea-salt records in snow from this area revealed extensive modifications, with Cl/Na+ ratios as low as 0.2. Statistical analysis showed a strong association between the slope and variations in Cl/Na+ ratios along the transect (r = −0.676, 99% confidence level. While distance from the coast accounted for some variability, the altitude by itself has no significant control over the sea-salt ion variability. However, the steep slopes influence the deposition of sea-salt aerosols in snow. The wind redistribution of snow due to the steep slopes on the coastal escarpment increases the concentration of Na+, resulting in a low Cl/Na+ ratios. We propose that the slope variations in the coastal regions of Antarctica could significantly influence the sea-salt chemistry of snow.

  20. A ripple-spreading genetic algorithm for the aircraft sequencing problem.

    Science.gov (United States)

    Hu, Xiao-Bing; Di Paolo, Ezequiel A

    2011-01-01

    When genetic algorithms (GAs) are applied to combinatorial problems, permutation representations are usually adopted. As a result, such GAs are often confronted with feasibility and memory-efficiency problems. With the aircraft sequencing problem (ASP) as a study case, this paper reports on a novel binary-representation-based GA scheme for combinatorial problems. Unlike existing GAs for the ASP, which typically use permutation representations based on aircraft landing order, the new GA introduces a novel ripple-spreading model which transforms the original landing-order-based ASP solutions into value-based ones. In the new scheme, arriving aircraft are projected as points into an artificial space. A deterministic method inspired by the natural phenomenon of ripple-spreading on liquid surfaces is developed, which uses a few parameters as input to connect points on this space to form a landing sequence. A traditional GA, free of feasibility and memory-efficiency problems, can then be used to evolve the ripple-spreading related parameters in order to find an optimal sequence. Since the ripple-spreading model is the centerpiece of the new algorithm, it is called the ripple-spreading GA (RSGA). The advantages of the proposed RSGA are illustrated by extensive comparative studies for the case of the ASP.

  1. AIRCRAFT MAINTENANCE HANGAR

    National Research Council Canada - National Science Library

    GEAMBASU Gabriel George

    2017-01-01

    .... The first part of research describes the aircraft maintenance process that has to be done after an updated maintenance manual according with aircraft type, followed by a short introduction about maintenance hangar...

  2. Land uplift and relative sea-level changes in the Loviisa area, southeastern Finland, during the last 8000 years

    Energy Technology Data Exchange (ETDEWEB)

    Miettinen, A.; Eronen, M.; Hyvaerinen, H. [Helsinki Univ. (Finland). Dept. of Geology

    1999-09-01

    Southeastern Finland belongs to the area covered by the Weichselian ice sheet, where the release of the ice load caused a rapid isostatic rebound during the postglacial time. While the mean overall apparent uplift is of the order of 2 mm/yr today, in the early Holocene time it was several times higher. A marked decrease in the rebound rate occurred around 8500 BP, however, since then the uplift rate has remained high until today, with a slightly decreasing trend towards the present time. According to current understanding there have neither been temporary increases nor decreases in the rate of uplift during the postglacial time. Even so, it is not known for sure whether there are regional irregularities on the rebound in Finland. Concurrently with land uplift, relative sea-level changes in the Baltic basin were also strongly affected by the global eustatic rise of sea-level. During the early Litorina Sea stage on the southern coast of Finland around 7000 BP, the rise in sea-level exceeded the rate of land uplift, and resulted in a short-lived transgression. The most accurate information on relative sea-level changes in an uplifting area may be obtained from radiocarbon dated events of isolation in small lake basins, as they were cut off from larger bodies of water. The isolations of such basins from the sea may be reliably determined by the recorded changes in the diatom flora in the sediment sequences, at horizons which may be radiometrically dated. In the present study, the isolation-horizons of 13 basins were dated by 26 conventional and 2 AMS radiocarbon dates. According to the available sets of dates, the time span of emergence extends from 8300 BP to the past few hundred years, for lakes from c. 30 m to 1.1 m above the present sea-level. Due to the global rise in sea-level, during the period of 7500-6500 BP, the sea-level rise clearly exceeded the rate of uplift, and resulted in the Litorina transgression, which had an amplitude of around one metre. The

  3. Weighing the relative potential impacts of climate change and land-use change on an endangered bird

    Science.gov (United States)

    Climate change and land-use change are projected to be two of the greatest drivers of biodiversity loss over the coming century. Land-use change, particularly the conversion of more natural lands to agriculture or residential or commercial development has resulted in extensive h...

  4. An analysis of PILT-related payments and likely property tax liability of Federal resource management lands

    Science.gov (United States)

    Ervin G. Schuster; Paul R. Beckley; Jennifer M. Bushur; Krista M. Gebert; Michael J. Niccolucci

    1999-01-01

    This report stems from Congressional concern over the equivalency between Federal payments to counties containing Federal resource management lands, the likely tax liability, and other county-level benefits and costs associated with those lands. Results indicate that the overall tax liability on Federal lands is almost three times the Federal payments. A survey of...

  5. Weighing the relative potential impacts of climate change and land-use change on an endangered bird

    Science.gov (United States)

    Climate change and land-use change are projected to be two of the greatest drivers of biodiversity loss over the coming century. Land-use change, particularly the conversion of more natural lands to agriculture or residential or commercial development has resulted in extensive h...

  6. Water in urban planning, Salt Creek Basin, Illinois water management as related to alternative land-use practices

    Science.gov (United States)

    Spieker, Andrew Maute

    1970-01-01

    Water management can be an integral part of urban comprehensive planning in a large metropolitan area. Water both imposes constraints on land use and offers opportunities for coordinated land and water management. Salt Creek basin in Cook and Du Page Counties of the Chicago metropolitan area is typical of rapidly developing suburban areas and has been selected to illustrate some of these constraints and opportunities and to suggest the effects of alternative solutions. The present study concentrates on the related problems of ground-water recharge, water quality, management of flood plains, and flood-control measures. Salt Creek basin has a drainage area of 150 square miles. It is in flat to. gently rolling terrain, underlain by glacial drift as much as 200 feet thick which covers a dolomite aquifer. In 1964, the population of the basin was about 400,000, and 40 percent of the land was in urban development. The population is expected to number 550,000 to 650,000 by 1990, and most of the land will be taken by urban development. Salt Creek is a sluggish stream, typical of small drainage channels in the headwaters area of northeastern Illinois. Low flows of 15 to 25 cubic feet per second in the lower part of the basin consist largely of sewage effluent. Nearly all the public water supplies in the basin depend on ground water. Of the total pumpage of 27.5 million gallons per day, 17.5 million gallons per day is pumped from the deep (Cambrian-Ordovician) aquifers and 10 million gallons per day is pumped from the shallow (Silurian dolomite and glacial drift) aquifers. The potential yield of the shallow aquifers, particularly glacial drift in the northern part of the basin, far exceeds present use. The largest concentration of pumpage from the shallow ,aquifers is in the Hinsdale-La Grange area. Salt Creek serves as an important source of recharge to these supplies, particularly just east of Hinsdale. The entire reach of Salt Creek south and east of Elmhurst can be

  7. Distribution of phytobenthos in the Yakima River basin, Washington, in relation to geology, land use and other environmental factors

    Science.gov (United States)

    Leland, Harry V.

    1995-01-01

    Benthic-algal distributions in the Yakima River, Washington, basin were, examined in relation to geology, land use, water chemistry, and stream habitat using indicator-species classification (TWINSPAN) and canonical correspondence analysis (CCA). Algal assemblages identified byTWINSPAN were each associated with a narrow range of water-quality conditions. In the Cascade geologic province, where timber harvest and grazing are the dominant land uses, differences in community structure (CCA site scores) and concentrations of major ions (Ca and Mg) and nutrients (solute P, SiO2 and inorganic N) varied with dominant rock type of the basin. In agricultural areas of the Columbia Plateau province, differences in phytobenthos structure were based primarily on the degree of enrichment of dissolved solids, inorganic N, and solute P from irrigation-return flows and subsurface drainage. Habitat characteristics strongly correlated with community structure included reach altitude, turbidity, substratum embeddedness (Columbia Plateau), large woody-debris density (Cascade Range), and composition and density of the riparian vegetation. Algal biomass (AFDM) correlated with composition and density of the riparian vegetation but not with measured chemical-constituent concentrations. Nitrogen limitation in streams of the Cascade Range favored nitrogen-fixing blue-green algae and diatoms with endosymbiotic blue-greens, whereas nitrogen heterotrophs were abundant in agricultural areas of the Columbia Plateau.

  8. Phytomass and soil organic carbon inventories related to land cover classification and periglacial features in Taimyr Peninsula,Siberia

    Science.gov (United States)

    Ramage, J. L.; Hugelius, G.; Kuhry, P.; Palmtag, J.; Lashchinskiy, N.

    2012-12-01

    The predicted increase in atmospheric temperatures is expected to affect the turnover of soil organic carbon in permafrost soils through modifications of the soil thermal regime. However, the tundra biome is formed of a mosaic of diverse landscape types with differing patterns of soil organic carbon storage and partitioning. Among these, differences in e.g. vegetation diversity and soil movements due to freeze-thaw processes are of main importance for assessing potential C remobilization under a changing climate. In this study, we described the storage of soil organic carbon (SOC) and the aboveground phytomass carbon in relation to geomorphology and periglacial features for two areas on Taymir Peninsula (Arctic Russia). An average of 29.5 kg C m2, calculated by upscaling with a land cover classification, is stored in the upper soil meter at these two study sites. The mean C phytomass storage amounts to ca.0.406 Kg C m2, or only 1.38 % of the total SOC storage. The topography, at different scales, plays an important role in the carbon partitioning. High amounts of soil organic carbon are found in highland areas and within the patterned ground features found in peatlands. The highest amounts of aboveground phytomass carbon are found in deciduous shrubs and moss layers. The large variability in carbon distribution within land cover types among the sites reveals the challenge of upscaling the carbon storage values over the Arctic and thus highlights the necessity to carry out detailed field inventories in this region.

  9. How is water availability related to the land use and morphology of an inland valley wetland in Kenya?

    Science.gov (United States)

    Böhme, Beate; Becker, Mathias; Diekkrüger, Bernd; Förch, Gerd

    2016-06-01

    Small inland valley wetlands contribute substantially to the livelihoods of rural communities in East Africa. Their conversion into farmland is driven by water availability. We quantified spatial-temporal dynamics of water availability in a headwater wetland in the humid zone of Kenya. Climatic conditions, soil moisture contents, groundwater levels and discharge data were monitored. A land-use map and a digital elevation model of the valley bottom were created to relate variations in soil moisture to dominant land uses and valley morphology. Upland crops occupied about a third of the wetland area, while approximately a quarter of the wet, central part of the valley bottom was designated for flood-tolerant taro, grown either by itself or in association or in rotation with upland crops. Finally, natural vegetation was found in 3% of the mapped area, mainly in sections with nearpermanent soil saturation. The HBV rainfall-runoff model's overestimation of stream discharge during the long dry season of the hydrological year 2010/2011 can be explained by the strong seasonal impact of water abstraction on the wetland's water balance. Our study vividly demonstrates the necessity of multi-method approaches for assessing the impact of management practices on water availability in valley bottom wetlands in East Africa.

  10. Platform Camera Aircraft Detection for Approach Evaluation and Training

    Science.gov (United States)

    2007-03-01

    cameras. Consistent and easily available approach data provides positive reinforcement for pilots preparing to participate in ship- based evolutions...glideslope and lineup guarantee more accurate approach representations. Consistent depictions of aircraft approaches have the ability to provide positive ... reinforcement for pilots preparing to land at the ship. 3 D. ADVANTAGES Providing supplemental objective feedback improves the pilot’s landing

  11. Licencing and Training Reform in the Australian Aircraft Maintenance Industry

    Science.gov (United States)

    Hampson, Ian; Fraser, Doug

    2016-01-01

    The training and licencing of aircraft maintenance engineers fulfils a crucial protective function since it is they who perform and supervise aircraft maintenance and certify that planes are safe afterwards. In Australia, prior to training reform, a trades-based system of aircraft maintenance engineer training existed in an orderly relation with…

  12. Licencing and Training Reform in the Australian Aircraft Maintenance Industry

    Science.gov (United States)

    Hampson, Ian; Fraser, Doug

    2016-01-01

    The training and licencing of aircraft maintenance engineers fulfils a crucial protective function since it is they who perform and supervise aircraft maintenance and certify that planes are safe afterwards. In Australia, prior to training reform, a trades-based system of aircraft maintenance engineer training existed in an orderly relation with…

  13. Unmanned aircraft systems

    Science.gov (United States)

    Unmanned platforms have become increasingly more common in recent years for acquiring remotely sensed data. These aircraft are referred to as Unmanned Airborne Vehicles (UAV), Remotely Piloted Aircraft (RPA), Remotely Piloted Vehicles (RPV), or Unmanned Aircraft Systems (UAS), the official term used...

  14. Changes in the Floating Plastic Pollution of the Mediterranean Sea in Relation to the Distance to Land

    Science.gov (United States)

    Petit, Stéphanie; Elineau, Amanda; Bruzaud, Stéphane; Crebassa, Jean-Claude; Dumontet, Bruno; Martí, Elisa; Gorsky, Gabriel; Cózar, Andrés

    2016-01-01

    The composition, size distribution, and abundance of floating plastic debris in surface waters of the Mediterranean Sea were analyzed in relation to distance to land. We combined data from previously published reports with an intensive sampling in inshore waters of the Northwestern Mediterranean. The highest plastic concentrations were found in regions distant from from land as well as in the first kilometer adjacent to the coastline. In this nearshore water strip, plastic concentrations were significantly correlated with the nearness to a coastal human population, with local areas close to large human settlements showing hundreds of thousands of plastic pieces per km2. The ratio of plastic to plankton abundance reached particularly high values for the coastal surface waters. Polyethylene, polypropylene and polyamides were the predominant plastic polymers at all distances from coast (86 to 97% of total items), although the diversity of polymers was higher in the 1-km coastal water strip due to a higher frequency of polystyrene or polyacrylic fibers. The plastic size distributions showed a gradual increase in abundance toward small sizes indicating an efficient removal of small plastics from the surface. Nevertheless, the relative abundance of small fragments (< 2 mm) was higher within the 1-km coastal water strip, suggesting a rapid fragmentation down along the shoreline, likely related with the washing ashore on the beaches. This study constitutes a first attempt to determine the impact of plastic debris in areas closest to Mediterranean coast. The presence of a high concentration of plastic including tiny plastic items could have significant environmental, health and economic impacts. PMID:27556233

  15. Solving problems of modern land relations on the way of formation of competitive agrarian production in Ukraine

    Directory of Open Access Journals (Sweden)

    Skoruk Olena P.

    2014-01-01

    Full Text Available The goal of the article is identification of modern problems of conduct of the land reform and ways of their solution in the context of economic consequences for development of the competitive agrarian production in Ukraine. It identifies that the main task of completion of the land reform is creation of the land market, which would ensure transition of the right of ownership on land lots to an efficient land owner. The basis of this development are farms that combine the owner and master of land in one entity. The article shows that adoption of the Draft Law “On Agricultural Land Turnover” would facilitate development of this form of management. The article identifies main problems of the moratorium on agricultural land sales, namely: land black market activity, withdrawal from market turnover of land of about USD 40 thousand million cost and, as a result, impossibility for agrarians to apply mortgage. The article identifies gaps in the legislation with respect to state control over unclaimed shares and escheats, due to which the state budget does not receive significant amounts of money. It offers ways of solution of these problems through empowering the founded Goszembank, which should become a partner and support for development of small and medium farms after withdrawal of the moratorium on agricultural land sales, with relevant authorities.

  16. Serial Escape System For Aircraft Crews

    Science.gov (United States)

    Wood, Kenneth E.

    1990-01-01

    Emergency escape system for aircraft and aerospace vehicles ejects up to seven crewmembers, one by one, within 120 s. Intended for emergencies in which disabled craft still in stable flight at no more than 220 kn (113 m/s) equivalent airspeed and sinking no faster than 110 ft/s (33.5 m/s) at altitudes up to 50,000 ft (15.2 km). Ejection rockets load themselves from magazine after each crewmember ejected. Jumpmaster queues other crewmembers and helps them position themselves on egress ramp. Rockets pull crewmembers clear of aircraft structure. Provides orderly, controlled exit and avoids ditching at sea or landing in rough terrain.

  17. The UNESCO-IHP Working Group on Land Subsidence: Four Decades of International Contributions to Hydrogeological Related Subsidence Research and Knowledge Exchange

    Science.gov (United States)

    Galloway, D. L.; Carreon-Freyre, D.; Teatini, P.; Ye, S.

    2015-12-01

    Subsidence is globally prevalent and because much of it is related to hydrological processes affected by human development of local land and water resources, "Land Subsidence" was included in the UNESCO programme of the International Hydrological Decade (IHD), 1965-1974 and an ad hoc working group on land subsidence was formed. In 1975 subsidence was retained under the framework of the UNESCO IHP (subproject 8.4: "Investigation of Land Subsidence due to Groundwater Exploitation"), and UNESCO IHP formerly codified the Working Group on Land Subsidence (WGLS). In 1984 the WGLS produced a comprehensive guidebook to serve scientists and engineers, confronting land subsidence problems, particularly in developing countries (http://unesdoc.unesco.org/$other/unesdoc/pdf/065167eo.pdf). During the IHD, UNESCO IHP convened the 1st International Symposium on Land Subsidence in 1969 in Tokyo, Japan. In collaboration with UNESCO IHP, IAHS, and other scientific organizations, the WGLS has convened eight more International Symposia on Land Subsidence in different countries in Asia, Europe and North America. The 9 published symposia proceedings constitute an important source of global subsidence research and case studies during the past 45 years, covering both anthropogenic and natural subsidence processes. Currently, the WGLS comprising 20 subsidence experts from 9 countries promotes and facilitates the international exchange of information regarding the design, implementation and evaluation of risk assessments and mitigation measures, the definition of water and land resource-management strategies that support sustainable development in areas vulnerable to subsidence (http://landsubsidence-unesco.org), and the assessment of related geological risks such as earth fissuring and fault activation (www.igcp641.org). The WGLS has become an important global leader in promoting subsidence awareness, scientific research and its application to subsidence monitoring, analysis and management.

  18. 土地城镇化及相关问题研究综述%Review of Research on Land Urbanization and Related Studies

    Institute of Scientific and Technical Information of China (English)

    李昕; 文婧; 林坚

    2012-01-01

    中国正经历着大规模的高速城镇化过程,与人口城镇化相伴随的是土地的急速城镇化,而关于“冒进土地城镇化”的提法和关注甚多但讲法不一。为了厘清土地城镇化的概念、内涵及度量方法,本文回顾并评述了土地城镇化及其相关问题的研究进展,对土地城镇化问题进行了再思考。现阶段中国土地城镇化不仅仅是农用地转换用途的非农化过程,越来越被关注的是农村建设用地转变为城镇建设用地以及建设用地的效率提升。本文认为土地城镇化应为土地从非城镇状态向城镇状态转变的过程,并提出以城镇建设用地与城乡建设用地的比值作为土地城镇化率的衡量指标。以此出发,土地城镇化问题今后的研究重点包括:土地城镇化和人口城镇化的匹配研究、时空格局和驱动机制研究、城乡实体空间划分、城镇空间扩张研究和用地效率转变研究。%In the rapid urbanization process of China, urbanized land expands quickly at the same pace as urban- ized population grows. Recent researches have been focused on land urbanization which considers the urbaniza- tion of land in current China as a reckless rash which is incompatibly faster than the urbanization of population and moreover, results in understandable inefficiency. To clarify the definition, the implication and the measure- ment of land urbanization, the authors have reviewed related literatures on urban expansion, urban sprawl, land use conversion, especially those in China; analyzed the reality and background of urbanization of land under the rural-urban dual land system in China; then developed the definition of land urbanization as the transition of land to construction land with urban attributes. The definition includes not only the commonly agreed transition of rural farmland to urban construction land, but also the transition of rural construction land to urban construc

  19. Analysis of the Intra-City Variation of Urban Heat Island and its Relation to Land Surface/cover Parameters

    Science.gov (United States)

    Gerçek, D.; Güven, İ. T.; Oktay, İ. Ç.

    2016-06-01

    Along with urbanization, sealing of vegetated land and evaporation surfaces by impermeable materials, lead to changes in urban climate. This phenomenon is observed as temperatures several degrees higher in densely urbanized areas compared to the rural land at the urban fringe particularly at nights, so-called Urban Heat Island. Urban Heat Island (UHI) effect is related with urban form, pattern and building materials so far as it is associated with meteorological conditions, air pollution, excess heat from cooling. UHI effect has negative influences on human health, as well as other environmental problems such as higher energy demand, air pollution, and water shortage. Urban Heat Island (UHI) effect has long been studied by observations of air temperature from thermometers. However, with the advent and proliferation of remote sensing technology, synoptic coverage and better representations of spatial variation of surface temperature became possible. This has opened new avenues for the observation capabilities and research of UHIs. In this study, "UHI effect and its relation to factors that cause it" is explored for İzmit city which has been subject to excess urbanization and industrialization during the past decades. Spatial distribution and variation of UHI effect in İzmit is analysed using Landsat 8 and ASTER day & night images of 2015 summer. Surface temperature data derived from thermal bands of the images were analysed for UHI effect. Higher temperatures were classified into 4 grades of UHIs and mapped both for day and night. Inadequate urban form, pattern, density, high buildings and paved surfaces at the expanse of soil ground and vegetation cover are the main factors that cause microclimates giving rise to spatial variations in temperatures across cities. These factors quantified as land surface/cover parameters for the study include vegetation index (NDVI), imperviousness (NDISI), albedo, solar insolation, Sky View Factor (SVF), building envelope

  20. ANALYSIS OF THE INTRA-CITY VARIATION OF URBAN HEAT ISLAND AND ITS RELATION TO LAND SURFACE/COVER PARAMETERS

    Directory of Open Access Journals (Sweden)

    D. Gerçek

    2016-06-01

    Full Text Available Along with urbanization, sealing of vegetated land and evaporation surfaces by impermeable materials, lead to changes in urban climate. This phenomenon is observed as temperatures several degrees higher in densely urbanized areas compared to the rural land at the urban fringe particularly at nights, so-called Urban Heat Island. Urban Heat Island (UHI effect is related with urban form, pattern and building materials so far as it is associated with meteorological conditions, air pollution, excess heat from cooling. UHI effect has negative influences on human health, as well as other environmental problems such as higher energy demand, air pollution, and water shortage. Urban Heat Island (UHI effect has long been studied by observations of air temperature from thermometers. However, with the advent and proliferation of remote sensing technology, synoptic coverage and better representations of spatial variation of surface temperature became possible. This has opened new avenues for the observation capabilities and research of UHIs. In this study, "UHI effect and its relation to factors that cause it" is explored for İzmit city which has been subject to excess urbanization and industrialization during the past decades. Spatial distribution and variation of UHI effect in İzmit is analysed using Landsat 8 and ASTER day & night images of 2015 summer. Surface temperature data derived from thermal bands of the images were analysed for UHI effect. Higher temperatures were classified into 4 grades of UHIs and mapped both for day and night. Inadequate urban form, pattern, density, high buildings and paved surfaces at the expanse of soil ground and vegetation cover are the main factors that cause microclimates giving rise to spatial variations in temperatures across cities. These factors quantified as land surface/cover parameters for the study include vegetation index (NDVI, imperviousness (NDISI, albedo, solar insolation, Sky View Factor (SVF, building

  1. LANDFORM MORPHOLOGIC RELATIONS BETWEEN INTER-GULLIED AND GULLIED LAND AREAS--A CASE STUDY OF THE WANGJIAGOU WATERSHED IN THE WEST OF SHANXI PROVINCE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Previous studies on erosional relations between inter-gullied and gullied lands have mainly concentrated on exploration of water and sediment relations, with few quantitative studies of evolution relations between inter-gullied land and gullied landform erosion in small catchments. This paper, using information from a 1:5000 digital orthophotomap (DOM), digital elevation model(DEM), and topographic map of the same period and of the same scale, quantitatively analyzes the impact and interactions of inter-gullied and gullied land geomorphologic characteristics on the dissected extent of a catchment using orthogonal polynomial regression analysis. Results indicate that gullies play a leading role in the catchment morphologic evolution and extent of cracked ground surface. When inter-gullied land areas are the same, a 0. 1 km2 gullied land area has the maximum effect on the erosive evolution intensity of the catchment cracked degree. The smaller the catchment area is, the greater the extent of cracked ground surface and gully intensity would be. The geomorphologic evolution mechanism of gullied catchments can be explained as a function of geomorphologic indicators of inter-gullied and gullied land characteristics.

  2. Autonomous precision approach and landing system (APALS)

    Science.gov (United States)

    Dieffenbach, Otto W.

    1995-06-01

    The APALSTM system is a precision approach and landing system designed to enable low visibility landings at many more airports than is now possible. It is an autonomous navigation system which uses standard avionics equipment to determine the aircraft position and altitude with respect to unique features over which the aircraft flies. The primary measurement is made with the aircraft's weather radar and provides the range and range rate information necessary to update the precision navigation system. The system makes use of stored terrain map data as references for map matching with Synthetic Aperture Radar maps.

  3. Can biofuels be a solution to climate change? The implications of land use change-related emissions for policy

    Science.gov (United States)

    Khanna, Madhu; Crago, Christine L.; Black, Mairi

    2011-01-01

    Biofuels have gained increasing attention as an alternative to fossil fuels for several reasons, one of which is their potential to reduce the greenhouse gas (GHG) emissions from the transportation sector. Recent studies have questioned the validity of claims about the potential of biofuels to reduce GHG emissions relative to the liquid fossil fuels they are replacing when emissions owing to direct (DLUC) and indirect land use changes (ILUC) that accompany biofuels are included in the life cycle GHG intensity of biofuels. Studies estimate that the GHG emissions released from ILUC could more than offset the direct GHG savings by producing biofuels and replacing liquid fossil fuels and create a ‘carbon debt’ with a long payback period. The estimates of this payback period, however, vary widely across biofuels from different feedstocks and even for a single biofuel across different modelling assumptions. In the case of corn ethanol, this payback period is found to range from 15 to 200 years. We discuss the challenges in estimating the ILUC effect of a biofuel and differences across biofuels, and its sensitivity to the assumptions and policy scenarios considered by different economic models. We also discuss the implications of ILUC for designing policies that promote biofuels and seek to reduce GHG emissions. In a first-best setting, a global carbon tax is needed to set both DLUC and ILUC emissions to their optimal levels. However, it is unclear whether unilateral GHG mitigation policies, even if they penalize the ILUC-related emissions, would increase social welfare and lead to optimal emission levels. In the absence of a global carbon tax, incentivizing sustainable land use practices through certification standards, government regulations and market-based pressures may be a viable option for reducing ILUC. PMID:22482030

  4. Long Term Empirical Relations between Storm Characteristics and Episodic Groundwater Recharge across Geographic and Land-Use Gradients

    Science.gov (United States)

    Tashie, A.; Mirus, B. B.; Pavelsky, T.

    2015-12-01

    Shallow aquifers are an important water resource and provide baseflow to streams, yet estimating rates of groundwater recharge is difficult. While climate change is predicted to increase the frequency and magnitude of extreme precipitation events, the resulting impact on recharge remains poorly understood. We quantify empirical relations between precipitation characteristics and episodic groundwater recharge for a wide variety of geographic and land-use types across North Carolina. We extract storm duration, magnitude, average rate, and storm intensity from precipitation records over periods of twelve to thirty-five years at ten locations, for a total of 3,544 individual storm events. Using time-series of water-table fluctuations from nearby monitoring wells, we estimate relative recharge to precipitation ratios (RPR) to identify statistical trends. RPR increases with increased storm duration, whereas RPR decreases with increasing magnitude, average rate, and intensity. Agricultural and urban areas exhibit the greatest decrease in RPR due to increasing storm magnitude, average rate, and intensity, while naturally vegetated areas exhibit a larger increase in RPR with increased storm duration. Though RPR is generally higher during the winter than the summer, this seasonal effect is magnified in the Appalachian and Piedmont regions. These statistical trends provide valuable insights into the likely consequences of climate and land-use change for water resources in humid, subtropical climates in the American southeast. If, as predicted, growing seasons lengthen and the intensity of storms increases with a warming climate, decreased recharge in Appalachia, the Piedmont, and rapidly growing urban areas in the region would further limit groundwater availability.

  5. GRAPHICAL MODELS OF THE AIRCRAFT MAINTENANCE PROCESS

    Directory of Open Access Journals (Sweden)

    Stanislav Vladimirovich Daletskiy

    2017-01-01

    Full Text Available The aircraft maintenance is realized by a rapid sequence of maintenance organizational and technical states, its re- search and analysis are carried out by statistical methods. The maintenance process concludes aircraft technical states con- nected with the objective patterns of technical qualities changes of the aircraft as a maintenance object and organizational states which determine the subjective organization and planning process of aircraft using. The objective maintenance pro- cess is realized in Maintenance and Repair System which does not include maintenance organization and planning and is a set of related elements: aircraft, Maintenance and Repair measures, executors and documentation that sets rules of their interaction for maintaining of the aircraft reliability and readiness for flight. The aircraft organizational and technical states are considered, their characteristics and heuristic estimates of connection in knots and arcs of graphs and of aircraft organi- zational states during regular maintenance and at technical state failure are given. It is shown that in real conditions of air- craft maintenance, planned aircraft technical state control and maintenance control through it, is only defined by Mainte- nance and Repair conditions at a given Maintenance and Repair type and form structures, and correspondingly by setting principles of Maintenance and Repair work types to the execution, due to maintenance, by aircraft and all its units mainte- nance and reconstruction strategies. The realization of planned Maintenance and Repair process determines the one of the constant maintenance component. The proposed graphical models allow to reveal quantitative correlations between graph knots to improve maintenance processes by statistical research methods, what reduces manning, timetable and expenses for providing safe civil aviation aircraft maintenance.

  6. 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

  7. 城镇土地保有成本与节约集约利用%Tenure Cost of Urban Land Relation to Economical & Intensive Utilization of Land Resource

    Institute of Scientific and Technical Information of China (English)

    周金龙

    2011-01-01

    The paper discussed on the cost of urban land tenure in China and found the difference in its intension and effect at home and abroad, in view of the present situation with the low cost and few control means, the role of cost of land tenure in land intensively use was emphasized. Finally, to increase the cost of land tenure and implement time-limited land right grant were put forward as the relative suggestions.%围绕城镇土地保有成本展开讨论,分析国内外城市土地保有成本的异同。针对当前中国城镇土地保有环节成本过低和调控手段较少的现状,重点分析土地保有成本对土地资源节约集约利用的作用,提出了增加土地保有环节成本和实行土地有限期出让的建议。

  8. CID Aircraft slap-down

    Science.gov (United States)

    1984-01-01

    , 1984, more than four years of effort passed trying to set-up final impact conditions considered survivable by the FAA. During those years while 14 flights with crews were flown the following major efforts were underway: NASA Dryden developed the remote piloting techniques necessary for the B-720 to fly as a drone aircraft; General Electric installed and tested four degraders (one on each engine); and the FAA refined AMK (blending, testing, and fueling a full-size aircraft). The 15 flights had 15 takeoffs, 14 landings and a larger number of approaches to about 150 feet above the prepared crash site under remote control. These flight were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. On the final flight (No. 15) with no crew, all fuel tanks were filled with a total of 76,000 pounds of AMK and the remotely-piloted aircraft landed on Rogers Dry Lakebed in an area prepared with posts to test the effectiveness of the AMK in a controlled impact. The CID, which some wags called the Crash in the Desert, was spectacular with a large fireball enveloping and burning the B-720 aircraft. From the standpoint of AMK the test was a major set-back, but for NASA Langley, the data collected on crashworthiness was deemed successful and just as important.

  9. CID Aircraft slap-down

    Science.gov (United States)

    1984-01-01

    , 1984, more than four years of effort passed trying to set-up final impact conditions considered survivable by the FAA. During those years while 14 flights with crews were flown the following major efforts were underway: NASA Dryden developed the remote piloting techniques necessary for the B-720 to fly as a drone aircraft; General Electric installed and tested four degraders (one on each engine); and the FAA refined AMK (blending, testing, and fueling a full-size aircraft). The 15 flights had 15 takeoffs, 14 landings and a larger number of approaches to about 150 feet above the prepared crash site under remote control. These flight were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. On the final flight (No. 15) with no crew, all fuel tanks were filled with a total of 76,000 pounds of AMK and the remotely-piloted aircraft landed on Rogers Dry Lakebed in an area prepared with posts to test the effectiveness of the AMK in a controlled impact. The CID, which some wags called the Crash in the Desert, was spectacular with a large fireball enveloping and burning the B-720 aircraft. From the standpoint of AMK the test was a major set-back, but for NASA Langley, the data collected on crashworthiness was deemed successful and just as important.

  10. Pilot Preferences on Displayed Aircraft Control Variables

    Science.gov (United States)

    Trujillo, Anna C.; Gregory, Irene M.

    2013-01-01

    The experiments described here explored how pilots want available maneuver authority information transmitted and how this information affects pilots before and after an aircraft failure. The aircraft dynamic variables relative to flight performance were narrowed to energy management variables. A survey was conducted to determine what these variables should be. Survey results indicated that bank angle, vertical velocity, and airspeed were the preferred variables. Based on this, two displays were designed to inform the pilot of available maneuver envelope expressed as bank angle, vertical velocity, and airspeed. These displays were used in an experiment involving control surface failures. Results indicate the displayed limitations in bank angle, vertical velocity, and airspeed were helpful to the pilots during aircraft surface failures. However, the additional information did lead to a slight increase in workload, a small decrease in perceived aircraft flying qualities, and no effect on aircraft situation awareness.

  11. Bringing The Land Foundation Back to Earth: a new model for the critical analysis of relational art

    Directory of Open Access Journals (Sweden)

    Clare Veal

    2014-04-01

    Full Text Available In 1998, the publishing of Nicolas Bourriaud's Relational Aesthetics drew together a group of contemporary art practices that took human relationships as their medium. These practices presented a significant problem for conventional art criticism, which either took an approach based on notions of artistic ethics or an approach that valued the avant-garde and “antagonism.” In this paper, the limitations of these critical approaches are addressed and the field of critical attention expanded towards an analysis of a work's discursive dimensions, operating beyond its immediate physical manifestation. Expanding analysis in this way introduces a tension between the lived temporality of relational works, as experienced by a limited audience, and their fictional dimensions within contemporary artistic discourse. Distinguishing between these two interrelated dimensions of relational works opens up the space for criticism between the work's idealistic or utopian aims and the reality of their effectiveness in a contemporary capitalist context. This critical approach is tested against the case study of Rirkrit Tiravanija and Kamin Lertchaiprasert's project, The Land Foundation in Northern Thailand. The project, a functioning farm, which also includes houses and structures by international artists and artists’ groups, including Superflex and Philippe Parreno, effectively demonstrates this tension between the work's apparently successful utopian, fictional dimension and the reality of its isolated physical manifestation. In separating the work's physical and discursive forms in this way, one is therefore able to create space for the evaluation of its political and artistic efficacy in its entirety.

  12. Land use regression models as a tool for short, medium and long term exposure to traffic related air pollution.

    Science.gov (United States)

    Dons, Evi; Van Poppel, Martine; Int Panis, Luc; De Prins, Sofie; Berghmans, Patrick; Koppen, Gudrun; Matheeussen, Christine

    2014-04-01

    In the HEAPS (Health Effects of Air Pollution in Antwerp Schools) study the importance of traffic-related air pollution on the school and home location on children's health was assessed. 130 children (aged 6 to 12) from two schools participated in a biomonitoring study measuring oxidative stress, inflammation and cardiovascular markers. Personal exposure of schoolchildren to black carbon (BC) and nitrogen dioxide (NO2) was assessed using both measured and modeled concentrations. Air quality measurements were done in two seasons at approximately 50 locations, including the schools. The land use regression technique was applied to model concentrations at the children's home address and at the schools. In this paper the results of the exposure analysis are given. Concentrations measured at school 2h before the medical examination were used for assessing health effects of short term exposure. Over two seasons, this short term BC exposure ranged from 514 ng/m(3) to 6285 ng/m(3), and for NO2 from 11 μg/m(3) to 36 μg/m(3). An integrated exposure was determined until 10 days before the child's examination, taking into account exposures at home and at school and the time spent in each of these microenvironments. Land use regression estimates were therefore recalculated into daily concentrations by using the temporal trend observed at a fixed monitor of the official air quality network. Concentrations at the children's homes were modeled to estimate long term exposure (from 1457 ng/m(3) to 3874 ng/m(3) for BC; and from 19 μg/m(3) to 51 μg/m(3) for NO2). The land use regression technique proved to be a fast and accurate means for estimating long term and daily BC and NO2 exposure for children living in the Antwerp area. The spatial and temporal resolution was tailored to the needs of the epidemiologists involved in this study. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Ways of farming and ways of thinking: do farmers' mental models of the landscape relate to their land management practices?

    Directory of Open Access Journals (Sweden)

    Carole Vuillot

    2016-03-01

    Full Text Available The efficiency of the European Union's Common Agricultural Policy in mitigating the negative effects of agricultural intensification on the landscape and biodiversity is increasingly being questioned. Enhancing a reciprocal understanding of various stakeholders' mental models of agro-social-ecosystems has been proposed to trigger changes in both policy design and farmers' behaviors. However, the relationship between farmers' mental models and practices is rarely considered. Here, we explore the relationship between farmers' individual mental models (IMMs of the agricultural landscape and their land management practices. To do so, we developed a theoretical and methodological framework grounded in cognitive psychology and farming system research for eliciting and comparing IMMs and land management practices. We applied this framework in the Coteaux de Gascogne territory, a hilly crop-livestock region in southern France. We identified groups of farmers according to their cropland and semi-natural habitat management practices. The results of our quantitative and qualitative comparisons of mental models between farmer groups showed that the way of farming partly relates to farmers' ways of thinking about the landscape and highlighted the heterogeneity of IMMs between and within farmer groups. We found evidence that path-dependent factors that constrain farmers' practices can modify their mental models, e.g., the role of agricultural machinery. Our study illustrates how an interdisciplinary framework coupling mental models and farming systems approaches provides an opportunity to enhance our understanding of the relationships between farmers' world views and their practices. Moreover, our results challenge current ways of thinking and designing biodiversity conservation policies in farmed landscapes.

  14. Detecting land-cover change using mappable vegetation related indices: A case study from Sinharaja Man and the Biosphere Reserve

    Directory of Open Access Journals (Sweden)

    BD Madurapperuma

    2014-06-01

    Full Text Available This study evaluates multi-year changes of vegetation in the Sinharaja Man and the Biosphere (MAB reserve using mappable vegetation related indices viz., Normalized Difference Vegetation Index (NDVI and Burn Index (BI. Land-cover changes in the Sinharaja MAB reserve were detected using Landsat 7 ETM+ images for 1993, 2001, and 2005. Seven individual bands of each image were converted to new multiband files by layer stacking using ENVI® 4.5. Then the multiband files were re-projected to UTM Zone 44 North, WGS-84 Datum. Each data set was exported to ENVI® EX software package to detect the changes between time steps based on NDVI and BI using an image difference tool. Land-cover data, which were obtained from the DIVA GIS web portal, were compared with Landsat image data. Results of BI showed that the Sinharaja MAB reserve fringe was vulnerable to forest fire. For example, from 1993- 2001, 160 ha identified as burned area. In contrast, from 2001-2005, 79 ha burned, and for the entire period of 1993-2005, 10 ha burned. NDVI resulted in a 962 ha increase of vegetation prime at the western Sinharaja from 2001-2005. In addition, there was a 15 ha decrease in vegetation from 1993-2005. The results were visualized using an embedded 3D render window of Google Earth and 2D view of ArcGIS explorer online. In conclusion, in-situ ground truthing data is needed for the fire-influenced area for implementing sustainable forest resource management at the Sinharaja MAB reserve. Normal 0 false false false EN-GB X-NONE X-NONE

  15. Land-Sea relationships of climate-related records: example of the Holocene in the eastern Canadian Arctic and Greenland

    Science.gov (United States)

    de Vernal, Anne; Fréchette, Bianca; Hillaire-Marcel, Claude

    2017-04-01

    Anne de Vernal, Bianca Fréchette, Claude Hillaire-Marcel Important progresses have been made to reconstruct climate and ocean changes through time. However, there is often a hiatus between the land-based climate reconstructions and paleoceanographical data. The reconstructed parameters are not the same (e.g. surface air temperature vs. sea-surface temperature). Moreover, the spatial (local to regional) and temporal dimensions (seasonal, annual to multi-decadal) of proxy-data are often inconsistent, thus preventing direct correlation of time series and often leading to uncertainties in multi-site, multi-proxy compilations. Here, we address the issue of land-sea relationships in the eastern Canadian Arctic-Baffin Bay-Labrador Sea-western Greenland based on the examination of different climate-related information from marine cores (dinocysts) collected nearshore vs. offshore, ice cores (isotopes), fjord and lake data (pollen). The combined information tends to indicate that "climate" changes are not easily neither adequately captured by temperature and temperature shifts. However, the seasonal contrast of temperatures seems to be a key parameter. Whereas it is often attenuated offshore, it is generally easy to reconstruct nearshore, where water stratification is usually stronger. The confrontation of data also shows a relationship between ice core data and sea-ice cover and/or sea-surface salinity, suggesting that air-sea exchanges in basins surrounding ice sheets play a significant role with respect to their isotopic composition. On the whole, combined onshore-offshore data consistently suggest a two-step shift towards optimal summer and winter conditions the circum Baffin Bay and northern Labrador Sea at 7.5 and 6 ka BP. These delayed optimal conditions seem to result from ice-meltwater discharges maintaining low salinity conditions in marine surface waters and thus a strong seasonality.

  16. Cross Cutting Relative Navigation Technologies for Improved Landing Accuracy and Vehicle-to-Vehicle Rendezvous and Docking

    Science.gov (United States)

    Miller, K. L.; Masciarelli, J.; Rohrschneider, R. R.

    2012-06-01

    This presentation addresses recent development and test progress, as well as future technology advancement plans for precision landing and Autonomous Rendezvous, Proximity Operations and Docking (ARPOD).

  17. Spatial distribution and transport of heavy metals in soil, ponded-surface water and grass in a pb-contaminated watershed as related to land-use practices.

    Science.gov (United States)

    Panichayapichet, P; Nitisoravut, S; Simachaya, W

    2007-12-01

    The aim of this study was to investigate the spatial distribution of heavy metal in soil and evaluate the dissolution of metal from soil to ponded-surface water, leaching through soil profiles and metal uptake in grass as related to different land-use practices. The data provided a scientific basis for best-management practices for land use in Khli Ti watershed. The watershed has a Pb-contamination problem from the previous operation of a Pb-ore concentrator and abandoned Zn-Pb mine. Sampling sites were selected from a land-use map, with land-use types falling into the following four categories: forest, agricultural land, residential area and road. Soil, ponded-surface water, grass samples and soil profiles were collected. The study related soil characteristics from different land-use practices and locations with observed metal concentrations in ponded-surface water and soil. High enrichment factors of Pb and As in soil were found. Partitioning coefficient, K(d) values were in the order: Cr > Pb > Ni > Cu > Cd > Zn. Soil disturbance from land-use activities including tillage and traffic increased leaching of trace metal from soils. Pb in soil was significantly taken up by grass even though the Transfer Factor, TF values were rather low. Agricultural activities in the watershed must be limited. Moreover, land encroachments in the upper and middle part of the watershed which have high potential of Pb must be strictly controlled in order to reduce the Pb contamination from non-point sources.

  18. Landing Gear Door Liners for Airframe Noise Reduction

    Science.gov (United States)

    Jones, Michael G. (Inventor); Howerton, Brian M. (Inventor); Van De Ven, Thomas (Inventor)

    2014-01-01

    A landing gear door for retractable landing gear of aircraft includes an acoustic liner. The acoustic liner includes one or more internal cavities or chambers having one or more openings that inhibit the generation of sound at the surface and/or absorb sound generated during operation of the aircraft. The landing gear door may include a plurality of internal chambers having different geometries to thereby absorb broadband noise.

  19. A NASA study of the impact of technology on future carrier based tactical aircraft - Overview

    Science.gov (United States)

    Wilson, S. B., III

    1992-01-01

    This paper examines the impact of technology on future carrier based tactical aircraft. The results were used in the Center for Naval Analysis Future Carrier Study. The NASA Team designed three classes of aircraft ('Fighter', 'Attack', and 'Multimission') with two different technology levels. The Multimission aircraft were further analyzed by examining the penalty on the aircraft for both catapult launch/arrested landing recovery (Cat/trap) and short take-off/vertical landing (STOVL). The study showed the so-called STOVL penalty was reduced by engine technology and the next generation Strike Fighter will pay more penalty for Cat/trap than for STOVL capability.

  20. Relation between seasonally detrended shortwave infrared reflectance data and land surface moisture in semi-arid Sahel

    DEFF Research Database (Denmark)

    Olsen, Jørgen Lundegaard; Ceccato, Pietro; Proud, Simon Richard;

    2013-01-01

    In the Sudano-Sahelian areas of Africa droughts can have serious impacts on natural resources, and therefore land surface moisture is an important factor. Insufficient conventional sites for monitoring land surface moisture make the use of Earth Observation data for this purpose a key issue...

  1. Aircraft noise and quality of life around Frankfurt Airport.

    Science.gov (United States)

    Schreckenberg, Dirk; Meis, Markus; Kahl, Cara; Peschel, Christin; Eikmann, Thomas

    2010-09-01

    In a survey of 2,312 residents living near Frankfurt Airport aircraft noise annoyance and disturbances as well as environmental (EQoL) and health-related quality of life (HQoL) were assessed and compared with data on exposure due to aircraft, road traffic, and railway noise. Results indicate higher noise annoyance than predicted from general exposure-response curves. Beside aircraft sound levels source-related attitudes were associated with reactions to aircraft noise. Furthermore, aircraft noise affected EQoL in general, although to a much smaller extent. HQoL was associated with aircraft noise annoyance, noise sensitivity and partly with aircraft noise exposure, in particular in the subgroup of multimorbid residents. The results suggest a recursive relationship between noise and health, yet this cannot be tested in cross-sectional studies. Longitudinal studies would be recommendable to get more insight in the causal paths underlying the noise-health relationship.

  2. Aircraft Noise and Quality of Life around Frankfurt Airport

    Science.gov (United States)

    Schreckenberg, Dirk; Meis, Markus; Kahl, Cara; Peschel, Christin; Eikmann, Thomas

    2010-01-01

    In a survey of 2,312 residents living near Frankfurt Airport aircraft noise annoyance and disturbances as well as environmental (EQoL) and health-related quality of life (HQoL) were assessed and compared with data on exposure due to aircraft, road traffic, and railway noise. Results indicate higher noise annoyance than predicted from general exposure-response curves. Beside aircraft sound levels source-related attitudes were associated with reactions to aircraft noise. Furthermore, aircraft noise affected EQoL in general, although to a much smaller extent. HQoL was associated with aircraft noise annoyance, noise sensitivity and partly with aircraft noise exposure, in particular in the subgroup of multimorbid residents. The results suggest a recursive relationship between noise and health, yet this cannot be tested in cross-sectional studies. Longitudinal studies would be recommendable to get more insight in the causal paths underlying the noise-health relationship. PMID:20948931

  3. Aircraft Noise and Quality of Life around Frankfurt Airport

    Directory of Open Access Journals (Sweden)

    Thomas Eikmann

    2010-08-01

    Full Text Available In a survey of 2,312 residents living near Frankfurt Airport aircraft noise annoyance and disturbances as well as environmental (EQoL and health-related quality of life (HQoL were assessed and compared with data on exposure due to aircraft, road traffic, and railway noise. Results indicate higher noise annoyance than predicted from general exposure-response curves. Beside aircraft sound levels source-related attitudes were associated with reactions to aircraft noise. Furthermore, aircraft noise affected EQoL in general, although to a much smaller extent. HQoL was associated with aircraft noise annoyance, noise sensitivity and partly with aircraft noise exposure, in particular in the subgroup of multimorbid residents. The results suggest a recursive relationship between noise and health, yet this cannot be tested in cross-sectional studies. Longitudinal studies would be recommendable to get more insight in the causal paths underlying the noise-health relationship.

  4. Land use regression modeling of intra-urban residential variability in multiple traffic-related air pollutants

    Directory of Open Access Journals (Sweden)

    Baxter Lisa K

    2008-05-01

    Full Text Available Abstract Background There is a growing body of literature linking GIS-based measures of traffic density to asthma and other respiratory outcomes. However, no consensus exists on which traffic indicators best capture variability in different pollutants or within different settings. As part of a study on childhood asthma etiology, we examined variability in outdoor concentrations of multiple traffic-related air pollutants within urban communities, using a range of GIS-based predictors and land use regression techniques. Methods We measured fine particulate matter (PM2.5, nitrogen dioxide (NO2, and elemental carbon (EC outside 44 homes representing a range of traffic densities and neighborhoods across Boston, Massachusetts and nearby communities. Multiple three to four-day average samples were collected at each home during winters and summers from 2003 to 2005. Traffic indicators were derived using Massachusetts Highway Department data and direct traffic counts. Multivariate regression analyses were performed separately for each pollutant, using traffic indicators, land use, meteorology, site characteristics, and central site concentrations. Results PM2.5 was strongly associated with the central site monitor (R2 = 0.68. Additional variability was explained by total roadway length within 100 m of the home, smoking or grilling near the monitor, and block-group population density (R2 = 0.76. EC showed greater spatial variability, especially during winter months, and was predicted by roadway length within 200 m of the home. The influence of traffic was greater under low wind speed conditions, and concentrations were lower during summer (R2 = 0.52. NO2 showed significant spatial variability, predicted by population density and roadway length within 50 m of the home, modified by site characteristics (obstruction, and with higher concentrations during summer (R2 = 0.56. Conclusion Each pollutant examined displayed somewhat different spatial patterns

  5. Aircraft Noise Prediction

    OpenAIRE

    2014-01-01

    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper add...

  6. Noise Scaling and Community Noise Metrics for the Hybrid Wing Body Aircraft

    Science.gov (United States)

    Burley, Casey L.; Brooks, Thomas F.; Hutcheson, Florence V.; Doty, Michael J.; Lopes, Leonard V.; Nickol, Craig L.; Vicroy, Dan D.; Pope, D. Stuart

    2014-01-01

    An aircraft system noise assessment was performed for the hybrid wing body aircraft concept, known as the N2A-EXTE. This assessment is a result of an effort by NASA to explore a realistic HWB design that has the potential to substantially reduce noise and fuel burn. Under contract to NASA, Boeing designed the aircraft using practical aircraft design princip0les with incorporation of noise technologies projected to be available in the 2020 timeframe. NASA tested 5.8% scale-mode of the design in the NASA Langley 14- by 22-Foot Subsonic Tunnel to provide source noise directivity and installation effects for aircraft engine and airframe configurations. Analysis permitted direct scaling of the model-scale jet, airframe, and engine shielding effect measurements to full-scale. Use of these in combination with ANOPP predictions enabled computations of the cumulative (CUM) noise margins relative to FAA Stage 4 limits. The CUM margins were computed for a baseline N2A-EXTE configuration and for configurations with added noise reduction strategies. The strategies include reduced approach speed, over-the-rotor line and soft-vane fan technologies, vertical tail placement and orientation, and modified landing gear designs with fairings. Combining the inherent HWB engine shielding by the airframe with added noise technologies, the cumulative noise was assessed at 38.7 dB below FAA Stage 4 certification level, just 3.3 dB short of the NASA N+2 goal of 42 dB. This new result shows that the NASA N+2 goal is approachable and that significant reduction in overall aircraft noise is possible through configurations with noise reduction technologies and operational changes.

  7. Glyoxal yield from isoprene oxidation and relation to formaldehyde: chemical mechanism, constraints from SENEX aircraft observations, and interpretation of OMI satellite data

    OpenAIRE

    Miller, Christopher Chan; Jacob, Daniel J.; Marais, Eloise A.; Yu, Karen; Travis, Katherine R.; Kim, Patrick S.; Fisher, Jenny A; Zhu, Lei; Wolfe, Glenn M.; Keutsch, Frank N.; Kaiser, Jennifer; Min, Kyung-Eun; Brown, Steven S.; Rebecca A. Washenfelder; González Abad, Gonzalo

    2016-01-01

    Glyoxal (CHOCHO) is produced in the atmosphere by oxidation of volatile organic compounds (VOCs). It is measurable from space by solar backscatter along with formaldehyde (HCHO), another oxidation product of VOCs. Isoprene emitted by vegetation is the dominant source of CHOCHO and HCHO in most of the world. We use aircraft observations of CHOCHO and HCHO from the SENEX campaign over the Southeast US in summer 2013 to better understand the time-dependent yields from isoprene oxidation, their d...

  8. Longitudinal dynamics of a perching aircraft concept

    Science.gov (United States)

    Wickenheiser, Adam; Garcia, Ephrahim; Waszak, Martin

    2005-05-01

    This paper introduces a morphing aircraft concept whose purpose is to demonstrate a new bio-inspired flight capability: perching. Perching is a maneuver that utilizes primarily aerodynamics -- as opposed to thrust generation -- to achieve a vertical or short landing. The flight vehicle that will accomplish this is described herein with particular emphasis on its addition levels of actuation beyond the traditional aircraft control surfaces. A computer model of the aircraft is developed in order to predict the changes in applied aerodynamic loads as it morphs and transitions through different flight regimes. The analysis of this model is outlined, including a lifting-line-based analytical technique and a trim and stability analysis. These analytical methods -- compared to panel or computational fluid dynamics (CFD) methods -- are considered desirable for the analysis of a large number of vehicle configurations and flight conditions. The longitudinal dynamics of this aircraft are studied, and several interesting results are presented. Of special interest are the changes in vehicle dynamics as the aircraft morphs from a cruise configuration to initiate the perching maneuver. Changes in trim conditions and stability are examined as functions of vehicle geometry. The time response to changes in vehicle configuration is also presented.

  9. Quantification of the relative role of land-surface processes and large-scale forcing in dynamic downscaling over the Tibetan Plateau

    Science.gov (United States)

    Gao, Yanhong; Xiao, Linhong; Chen, Deliang; Chen, Fei; Xu, Jianwei; Xu, Yu

    2017-03-01

    Dynamical downscaling modeling (DDM) is important to understand regional climate change and develop local mitigation strategies, and the accuracy of DDM depends on the physical processes involved in the regional climate model as well as the forcing datasets derived from global models. This study investigates the relative role of the land surface schemes and forcing datasets in the DDM over the Tibet Plateau (TP), a region complex in topography and vulnerable to climate change. Three Weather Research and Forecasting model dynamical downscaling simulations configured with two land surface schemes [Noah versus Noah with multiparameterization (Noah-MP)] and two forcing datasets are performed over the period of 1980-2005. The downscaled temperature and precipitation are evaluated with observations and inter-compared regarding temporal trends, spatial distributions, and climatology. Results show that the temporal trends of the temperature and precipitation are determined by the forcing datasets, and the forcing dataset with the smallest trend bias performs the best. Relative to the forcing datasets, land surface processes play a more critical role in the DDM over the TP due to the strong heating effects on the atmospheric circulation from a vast area at exceptionally high elevations. By changing the vertical profiles of temperature in the atmosphere and the horizontal patterns of moisture advection during the monsoon seasons, the land surface schemes significantly regulate the downscaled temperature and precipitation in terms of climatology and spatial patterns. This study emphasizes the selection of land surface schemes is of crucial importance in the successful DDM over the TP.

  10. Effect of Construction Land Expansion on Energy-Related Carbon Emissions: Empirical Analysis of China and Its Provinces from 2001 to 2011

    Directory of Open Access Journals (Sweden)

    Xuankai Deng

    2015-06-01

    Full Text Available Construction land expansion significantly affects energy-related carbon emissions. This paper analyzed the effect of construction land expansion on energy-related carbon emissions in China and its provinces from 2001 to 2011 by using the logarithmic mean Divisia index method. We divided the study into two intervals (2001–2006 and 2006–2011 and categorized the 30 provinces of China into eight zones. Results indicated that construction land expansion exerted the second largest positive effect on carbon emission growth in China and in the 30 provinces from 2001 to 2011. The north, east, and south coastal regions as well as the middle Yellow River region, were the highly affected regions in the same period. Between the two study intervals, the effect of construction land expansion on carbon emissions decreased in China and in the coastal regions, but increased in inland regions. The Hebei, Shandong, Jiangsu, Zhejiang, Fujian, Guangdong, Yunnan, Chongqing, Ningxia, and Xinjiang provinces, which are concentrated in the north, east, and south coastal regions, were selected for the reduction of carbon emissions by controlling construction land expansion.

  11. Land Use Changes Analysis for Kelantan Basin Using Spatial Matrix Technique “Patch Analyst” in Relation to Flood Disaster

    Directory of Open Access Journals (Sweden)

    Tuan Pah Rokiah Syed Hussain

    2011-09-01

    Full Text Available In the recent decade, there are many government efforts to develop rural area as a step to curb vast economic discrepancy status within community in the nation. This effort is in line with National Development Policy promoted by government shifting from New Economic Policy. Therefore, this study area also has impact done by development activities. The enormous economic developments have encourage growth in urbanization, tourism and recreation, public facilities, housing and so on. Furthermore, the area of cultivation land uses and foliages are becoming shrinking due to development growth, which is development needs to shift land use pattern hence denotes that human beings infuriate the environment to meet the life needs. In response to that, this research delves into the level of land use changes using the Geographic Information System (GIS and Spatial Analyst to determine the actual area or vicinity and what is the type of rigorous changes in land use. This issue can be seen all the way through the study outcome via spatial analysis technique adapted from Patch Density & Size Metrics (Mean Patch Size, Edge Metrics (Total Edge (TE, Edge Density (ED, Mean Perimeter-Area Ratio (Mpar and Shannons Diversity Index (SHDI. Results of the study show that, land use changes have occurred significantly in the study area for the period of 20 years, wher, all types of analysis verify that there is an increase in patch for every statistical test. The increase in patch is a picture of current land use changes, land use edge density and land use area in study area. Moreover, this study investigates the relationship between land use with rising flood disaster frequency and intensity variable which has always happened lately in Kelantan River Basin.

  12. Changes in runoff in two neighbouring catchments in the Bohemian Forest related to climate and land cover changes

    Directory of Open Access Journals (Sweden)

    Bernsteinová Jana

    2015-12-01

    Full Text Available There is public concern that large-scale disturbances to forest cover caused by insects and storm winds in the Bohemian Forest could intensify high water flows and enhance the expected flooding risks predicted in current regional climate change scenarios. We analysed stream discharge in Upper Vydra and Große Ohe, neighbouring catchments in the Bohemian Forest, the largest contiguous forested area in Central Europe. Upper Vydra, in the Šumava National Park, and Große Ohe (including the Upper Große Ohe headwater catchment in the Bavarian Forest National Park are similar in size, but differ in land use cover and the extent of disturbed Norway spruce stands. Publicly available runoff and meteorological data (1978–2011 were examined using non-parametric trend and breakpoint analysis. Together with mapped vegetation cover changes, the results were used to address the following questions: 1 are there significant changes in the hydrological cycle and, if so, do these changes relate to 2 the extent and expansion of disturbance in forests stands and/or 3 altered precipitation dynamics and thermal conditions?

  13. Dynamics of births and juvenile recruitment in Mara-Serengeti ungulates in relation to climatic and land use changes

    NARCIS (Netherlands)

    Ogutu, Joseph O.; Piepho, Hans-Peter; Dublin, Holly T.; Bhola, Nina; Reid, Robin S.

    Natality and recruitment govern animal population dynamics, but their responses to fluctuating resources, competition, predation, shifting habitat conditions, density feedback and diseases are poorly understood. To understand the influences of climatic and land use changes on population dynamics, we

  14. Living Lands

    DEFF Research Database (Denmark)

    Christensen, Suna Møller

    2014-01-01

    , hunters attended to questions like safe-journeying on ice or the role of natural surroundings in children’s education, in ways revealing a relational perception of ‘nature’ and dissolving culture-nature dualisms. Hunters’ experiences in living the land afforded children a dwelling position from which...... of the social world pushes questions about education and life, disregarding being educated as human control of nature....

  15. Cable Tensiometer for Aircraft

    Science.gov (United States)

    Nunnelee, Mark (Inventor)

    2008-01-01

    The invention is a cable tensiometer that can be used on aircraft for real-time, in-flight cable tension measurements. The invention can be used on any aircraft cables with high precision. The invention is extremely light-weight, hangs on the cable being tested and uses a dual bending beam design with a high mill-volt output to determine tension.

  16. Development of a complex groundwater model to assess the relation among groundwater resource exploitation, seawater intrusion and land subsidence

    Science.gov (United States)

    Hsi Ting, Fang; Yih Chi, Tan; Chen, Jhong Bing

    2016-04-01

    The land subsidence, which is usually irreversible, in Taiwan Pintung Plain occurred due to groundwater overexploitation. Many of the land subsidence areas in Taiwan are located in coastal area. It could not only result in homeland loss, but also vulnerability to flooding because the function of drainage system and sea wall are weakened for the lowered ground surface. Groundwater salinization and seawater intrusion could happen more easily as well. This research focuses on grasping the trend of environmental change due to the damage and impact from inappropriate development of aquaculture in the last decades. The main task is developing the artificial neural networks (ANNs) and complex numerical model for conjunctive use of surface and groundwater which is composed of a few modules such as land use, land subsidence, contamination transportation and etc. An approach based on self-organizing map (SOM) is proposed to delineate groundwater recharge zones. Several topics will be studied such as coupling of surface water and groundwater modeling, assessing the benefit of improving groundwater resources by recharge, identifying the improper usage of groundwater resources, and investigating the effect of over-pumping on land subsidence in different depth. In addition, a complete plan for managing both the flooding and water resources will be instituted by scheming non-engineering adaptation strategies for homeland planning, ex. controlling pumping behavior in area vulnerable to land subsidence and increasing groundwater recharge.

  17. Greenhouse gas mitigation on marginal land: a quantitative review of the relative benefits of forest recovery versus biofuel production.

    Science.gov (United States)

    Evans, Samuel G; Ramage, Benjamin S; DiRocco, Tara L; Potts, Matthew D

    2015-02-17

    Decisions concerning future land-use/land cover change stand at the forefront of ongoing debates on how to best mitigate climate change. In this study, we compare the greenhouse gas (GHG) mitigation value over a 30-year time frame for a range of forest recovery and biofuel production scenarios on abandoned agricultural land. Carbon sequestration in recovering forests is estimated based on a statistical analysis of tropical and temperate studies on marginal land. GHGs offset by biofuel production are analyzed for five different production pathways. We find that forest recovery is superior to low-yielding biofuel production scenarios such as oil palm and corn. Biofuel production scenarios with high yields, such as sugarcane or high-yielding energy grasses, can be comparable or superior to natural forest succession and to reforestation in some cases. This result stands in contrast to previous research suggesting that restoring degraded ecosystems to their native state is generally superior to agricultural production in terms of GHG mitigation. Further work is needed on carbon stock changes in forests, soil carbon dynamics, and bioenergy crop production on degraded/abandoned agricultural land. This finding also emphasizes the need to consider the full range of social, economic, and ecological consequences of land-use policies.

  18. 14 CFR 23.1383 - Taxi and landing lights.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Taxi and landing lights. 23.1383 Section 23.1383 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Taxi and landing lights. Each taxi and landing light must be designed and installed so that: (a) No...

  19. Propulsion controlled aircraft research

    Science.gov (United States)

    Fullerton, C. Gordon

    1993-01-01

    The NASA Dryden Flight Research Facility has been conducting flight, ground simulator, and analytical studies to investigate the use of thrust modulation on multi-engine aircraft for emergency flight control. Two general methods of engine only control have been studied; manual manipulation of the throttles by the pilot, and augmented control where a computer commands thrust levels in response to pilot attitude inputs and aircraft motion feedbacks. This latter method is referred to as the Propulsion Controlled Aircraft (PCA) System. A wide variety of aircraft have been investigated. Simulation studies have included the B720, F-15, B727, B747 and MD-11. A look at manual control has been done in actual flight on the F15, T-38, B747, Lear 25, T-39, MD-11 and PA-30 Aircraft. The only inflight trial of the augmented (PCA) concept has been on an F15, the results of which will be presented below.

  20. Survival analysis of aging aircraft

    Science.gov (United States)

    Benavides, Samuel

    This study pushes systems engineering of aging aircraft beyond the boundaries of empirical and deterministic modeling by making a sharp break with the traditional laboratory-derived corrosion prediction algorithms that have shrouded real-world failures of aircraft structure. At the heart of this problem is the aeronautical industry's inability to be forthcoming in an accurate model that predicts corrosion failures in aircraft in spite of advances in corrosion algorithms or improvements in simulation and modeling. The struggle to develop accurate corrosion probabilistic models stems from a multitude of real-world interacting variables that synergistically influence corrosion in convoluted and complex ways. This dissertation, in essence, offers a statistical framework for the analysis of structural airframe corrosion failure by utilizing real-world data while considering the effects of interacting corrosion variables. This study injects realism into corrosion failures of aging aircraft systems by accomplishing four major goals related to the conceptual and methodological framework of corrosion modeling. First, this work connects corrosion modeling from the traditional, laboratory derived algorithms to corrosion failures in actual operating aircraft. This work augments physics-based modeling by examining the many confounding and interacting variables, such as environmental, geographical and operational, that impact failure of airframe structure. Examined through the lens of censored failure data from aircraft flying in a maritime environment, this study enhances the understanding between the triad of the theoretical, laboratory and real-world corrosion. Secondly, this study explores the importation and successful application of an advanced biomedical statistical tool---survival analysis---to model censored corrosion failure data. This well-grounded statistical methodology is inverted from a methodology that analyzes survival to one that examines failures. Third, this

  1. Land valuation and marginalization processes in cultural landscapes - a comparative study of valuation systems related to natural and semi-natural areas

    DEFF Research Database (Denmark)

    Christensen, Andreas Aagaard; Svenningsen, Stig Roar; Brandt, Jesper

    2012-01-01

    in 2008 - 2010 in the Maribo Lakes Nature Park, which is a Natura-2000 protected area situated on the island of Lolland in Southern Denmark. The major land owners, leaders in the tourism industry and leaders of local recreational associations in the area were interviewed about their land use practices...... not easily tangible aspects of natural and semi-natural areas are receiving increased interest, and where attempts to develop spatially weighted quantification measures for intangible landscape functions is being undertaken. This renewed interest in landscape intangibles seems to be motivated by a growing......, their preferences for different areas and their valuation procedures related to landscape and land cover. The maps developed with the interviewees were compared with maps delineating the 205 Natura-2000 habitat areas in the nature park which were designated by the Danish Nature Agency in 2006. Results...

  2. Land management and development

    DEFF Research Database (Denmark)

    Enemark, Stig

    2006-01-01

    Land management is the process by which the resources of land are put into good effect. Land management encompasses all activities associated with the management of land that are required to achieve sustainable development. The concept of land includes properties and natural resources and thereby...... encompasses the total natural and built environment. Land Administration Systems (LAS) are institutional frameworks complicated by the tasks they must perform, by national cultural, political and judicial settings, and by technology. This paper facilitates an overall understanding of the land management......, responsibilities, restrictions and risks in relation to land in support of sustainable development. The model is designed for developed economies but allows incremental adoption of the model by countries at transitional stages of economic development. The model reflects drivers of globalisation and technology...

  3. THE COMPLEX OF STANDS FOR TESTING THE AIR CUSHION CHASSIS OF AIRCRAFT AND VEHICLES

    Directory of Open Access Journals (Sweden)

    2016-01-01

    Full Text Available This article deals with a set of stands made in NIMK TSAGI for testing and creating the air cushion chassis for the aircraft and vehicles. It allows to fully embrace the process of developing and constructing the air cushion chassis for air- craft and solve problems relating to peculiarities of such aircraft on the takeoff, landing and movement in the elementary prepared and unprepared soil runways, flat terrain and water areas. The complex includes: the experimental installation to study aeroelasticity phenomena of the chassis in the extending and retracting process with simulation of aircraft and ekran- oplane takeoff and landing modes in the air flow, including the wind tunnels; the experimental stand with vertical screen for testing of ekranoplane models in T-5 wind tunnel of NIMC TsAGI, permitting to simultaneously vary the model’s posi- tion relatively to the screen, roll, pitch (angle of attack, and banking; mobile experimental stand with contact crawler gear, for experimental determination and comparative evaluation of the chassis with different patterns of formation and air cush- ion fences for all-year-round testing in natural conditions at elementary-prepared and unprepared sites and water areas. Based on mathematical simulation of flow past in the wind tunnel the possibility of use booth stand with vertical screen and experimental installation to study aeroelasticity phenomena of the chassis for experimental studies, respectively, by defini- tion of the aerodynamic characteristics of forces and moments of the air cushion aircraft and ekranoplanes models and the research of phenomena of aeroelasticity of flexible fencing is substantiated.

  4. Relative Contributions of Land Use and Climate Change to Water Supply Variations over Yellow River Source Area in Tibetan Plateau during the Past Three Decades.

    Science.gov (United States)

    Pan, Tao; Wu, Shaohong; Liu, Yujie

    2015-01-01

    There is increasing evidence of environmental change impacts on ecosystem processes and services, yet poor understanding of the relative contributions of land use and climate change to ecosystem services variations. Based on detailed meteorological, hydrological records and satellite data over the Yellow River Source Area (YRSA) in Tibetan Plateau from 1980s to 2008, together with a water-yield module of Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and also a Residual Trends (RESTREND) method, we assessed the water supply variations in YRSA during the past three decades and disentangled the relative contributions of land use and climate change. Results show that water supply significantly decreased from 1980 to 2005 and then increased from 2005 to 2008. The quantity slightly decreased from 283.01 mm in 1980 to 276.95 mm in 1995, 270.12 mm in 2000 and 267.97 mm in 2005, and it then rebounded slightly to 275.26 mm in 2008. The water supply variation ranged from 283.01 mm to 267.97 mm. Climate change contributed dominantly to water supply decrease from 1980 to 1995, which accounts for approximately 64% of the decrease. During 1995 to 2000, land use contributed more and about 58% to the water supply decrease as the intense human activities. From 2000 to 2005, climate change became a positive contribution to the water supply as the increased precipitation, but the land use still contributed negatively. From 2005 to 2008, both climate and land use have positive impacts, but land use contributed about 61% to the water supply increase. The implementation of the Three Rivers Source Area Ecological Protection Project has greatly improved the vegetation coverage conditions and the water retention ability during this period. We recommend that the implementation of ecological projects, grazing policies and artificial improvement of degraded grassland would help to conserve the water retention ability and increase water supply.

  5. Mosquito species diversity and abundance in relation to land use in a riceland agroecosystem in Mwea, Kenya.

    Science.gov (United States)

    Muturi, Ephantus J; Shililu, Josephat; Jacob, Benjamin; Gu, Weidong; Githure, John; Novak, Robert

    2006-06-01

    We conducted an entomological survey to determine the mosquito species diversity and abundance in relation to land use in the Mwea rice scheme, Kenya. Adult mosquitoes were collected by indoor spraying of houses and outdoors by CDC light traps in three villages representing planned (Mbuinjeru) and unplanned (Kiamachiri) rice agroecosystems and a non-irrigated agroecosystem (Murinduko). During the 12-month sampling period, a total of 98,708 mosquitoes belonging to five genera and 25 species were collected. The five most common species collected during this study were Anopheles arabiensis Patton (52.5%), Culex quinquefasciatus Say (36.7%), Anopheles pharoensis Theobald (5.2%), Anopheles coustani Laveran (1.4%), and Anopheles funestus Giles (1.3%). Anopheles arabiensis, Cx quinquefasciatus, and An. pharoensis were more abundant in rice agroecosystems than in the non-irrigated agroecosystem, and in planned than in the unplanned rice agroecosystems. In contrast, An. funestus was more abundant in the non-irrigated agroecosystem. The mosquito species diversity (H) and evenness (E(H)) in the non-irrigated agroecosystem (Shannon diversity Index, H = 1.507, EH = 0.503) was significantly higher than in the rice agroecosystems (H) = 0.968, E(H) = 0.313, unplanned; and H= 1.040, E(H) = 0.367 planned). Results of lag cross correlation analysis revealed a strong relationship between rainfall and the abundance of An. arabiensis, and C. quinquefasciatus in the non-irrigated agroecosystem but not in the rice agroecosystems. It is inferred from the data that different levels of habitat perturbations with regard to rice cultivation have different effects on mosquito diversity and abundance. This provides an understanding of how mosquito diversity is impacted by different habitat management and rice cropping strategies.

  6. Aircraft Low Altitude Wind Shear Detection and Warning System.

    Science.gov (United States)

    Sinclair, Peter C.; Kuhn, Peter M.

    1991-01-01

    There is now considerable evidence to substantiate the causal relationship between low altitude wind shear (LAWS) and the recent increase in low-altitude aircraft accidents. The National Research Council has found that for the period 1964 to 1982, LAWS was involved in nearly all the weather-related air carrier fatalities. However, at present, there is no acceptable method, technique, or hardware system that provides the necessary safety margins, for spatial and timely detection of LAWS from an aircraft during the critical phases of landing and takeoff. The Federal Aviation Administration (FAA) has addressed this matter and supports the development of an airborne system for detecting hazardous LAWS with at least a one minute warning of the potential hazard to the pilot. One of the purposes of this paper is to show from some of our preliminary flight measurement research that a forward looking infrared radiometer (FLIR) system can be used to successfully detect the cool downdraft of downbursts [microbursts/macrobursts (MB)] and thunderstorm gust front outflows that are responsible for most of the LAWS events. The FLIR system provides a much greater safety margin for the pilot than that provided by reactive designs such as inertial-air speed systems that require the actual penetration of the MB before a pilot warning can be initiated. Our preliminary results indicate that an advanced airborne FLIR system could provide the pilot with remote indication of MB threat, location, movement, and predicted MB hazards along the flight path ahead of the aircraft.In a proof-of-concept experiment, we have flight tested a prototype FLIR system (nonscanning, fixed range) near and within Colorado MBs with excellent detectability. The results show that a minimum warning time of one-four minutes (5×10 km), depending on aircraft speed, is available to the pilot prior to a MB encounter. Analysis of the flight data with respect to a modified `hazard index' indicates the severe hazard

  7. Contribution to the modelling and simulation of aircraft structures impacting on water

    OpenAIRE

    Toso, Nathalie Renée Solange

    2009-01-01

    The impact on water of aeronautical structures is of concern as soon as an aircraft is designed to operate over sea. For the need of the ditching certification, it can be summarised that the structure should be able to land on water and float long enough to enable the passengers and crew members to evacuate. Until the middle of the 90's, compliance to the regulations was mainly shown by tests performed in a basin using a mock-up structure completed by relative simple theoretical evaluations o...

  8. Aligning land use with land potential

    Science.gov (United States)

    Current agricultural land use is dominated by an emphasis on provisioning services by applying energy-intensive inputs through relatively uniform production systems across variable landscapes. This approach to agricultural land use is not sustainable. Integrated agricultural systems (IAS) are uphe...

  9. Emergency Highway Landings in General Aviation and the Possible Role of Media Reports.

    Science.gov (United States)

    Holzman, Emily; de Voogt, Alex

    2017-05-01

    To examine the causes and factors of airplane landings on highways and the dangers to occupants of vehicles on the ground. The U.S. National Transportation Safety Board online database provided 133 accidents involving a highway landing dating from 2000 to 2013. Supplemental information was sought in online media archives, which reported on 53 of these accidents. Collisions with highway-related objects, other options for landing, and witness accounts were added categories extracted from the narrative statements and media reports. Highway landings occur mostly due to mechanical failures, ineffective preflight or in-flight planning, and fuel exhaustion, in addition to a lack of alternate landing options for a pilot of a fixed-wing aircraft. Most of the landings (N = 108) lead to minor or no injuries at all. A significant proportion of 7 out of 19 collisions with powerlines resulted in a fatality, as opposed to other types of accidents. Collisions with motor vehicles (N = 29) caused minor (N = 23) and serious (N = 2) injuries to people on the ground. Main online media archives covered less than half of all accidents (39.8%). While highway landings are not a recommended landing alternative, mitigation strategies should include a focus on avoiding powerlines and vehicles on the ground. Unfortunately, online media archives are not yet a consistent source of information for general aviation accidents.Holzman E, de Voogt A. Emergency highway landings in general aviation and the possible role of media reports. Aerosp Med Hum Perform. 2017; 88(5):497-499.

  10. Predicting Visibility of Aircraft

    Science.gov (United States)

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

    2009-01-01

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

  11. Net land-atmosphere flows of biogenic carbon related to bioenergy: towards an understanding of systemic feedbacks.

    Science.gov (United States)

    Haberl, Helmut

    2013-07-01

    The notion that biomass combustion is carbon neutral vis-a-vis the atmosphere because carbon released during biomass combustion is absorbed during plant regrowth is inherent in the greenhouse gas accounting rules in many regulations and conventions. But this 'carbon neutrality' assumption of bioenergy is an oversimplification that can result in major flaws in emission accounting; it may even result in policies that increase, instead of reduce, overall greenhouse gas emissions. This commentary discusses the systemic feedbacks and ecosystem succession/land-use history issues ignored by the carbon neutrality assumption. Based on recent literature, three cases are elaborated which show that the C balance of bioenergy may range from highly beneficial to strongly detrimental, depending on the plants grown, the land used (including its land-use history) as well as the fossil energy replaced. The article concludes by proposing the concept of GHG cost curves of bioenergy as a means for optimizing the climate benefits of bioenergy policies.

  12. Scientific Infrastructure To Support Manned And Unmanned Aircraft, Tethered Balloons, And Related Aerial Activities At Doe Arm Facilities On The North Slope Of Alaska

    Science.gov (United States)

    Ivey, M.; Dexheimer, D.; Hardesty, J.; Lucero, D. A.; Helsel, F.

    2015-12-01

    The U.S. Department of Energy (DOE), through its scientific user facility, the Atmospheric Radiation Measurement (ARM) facilities, provides scientific infrastructure and data to the international Arctic research community via its research sites located on the North Slope of Alaska. DOE has recently invested in improvements to facilities and infrastructure to support operations of unmanned aerial systems for science missions in the Arctic and North Slope of Alaska. A new ground facility, the Third ARM Mobile Facility, was installed at Oliktok Point Alaska in 2013. Tethered instrumented balloons were used to make measurements of clouds in the boundary layer including mixed-phase clouds. A new Special Use Airspace was granted to DOE in 2015 to support science missions in international airspace in the Arctic. Warning Area W-220 is managed by Sandia National Laboratories for DOE Office of Science/BER. W-220 was successfully used for the first time in July 2015 in conjunction with Restricted Area R-2204 and a connecting Altitude Reservation Corridor (ALTRV) to permit unmanned aircraft to operate north of Oliktok Point. Small unmanned aircraft (DataHawks) and tethered balloons were flown at Oliktok during the summer and fall of 2015. This poster will discuss how principal investigators may apply for use of these Special Use Airspaces, acquire data from the Third ARM Mobile Facility, or bring their own instrumentation for deployment at Oliktok Point, Alaska. The printed poster will include the standard DOE funding statement.

  13. Weighing the relative potential impacts of climate change and land-use change on an endangered bird.

    Science.gov (United States)

    Bancroft, Betsy A; Lawler, Joshua J; Schumaker, Nathan H

    2016-07-01

    Climate change and land-use change are projected to be the two greatest drivers of biodiversity loss over the coming century. Land-use change has resulted in extensive habitat loss for many species. Likewise, climate change has affected many species resulting in range shifts, changes in phenology, and altered interactions. We used a spatially explicit, individual-based model to explore the effects of land-use change and climate change on a population of the endangered Red-cockaded Woodpecker (RCW; Picoides borealis). We modeled the effects of land-use change using multiple scenarios representing different spatial arrangements of new training areas for troops across Fort Benning. We used projected climate-driven changes in habitat and changes in reproductive output to explore the potential effects of climate change. We summarized potential changes in habitat based on the output of the dynamic vegetation model LPJ-GUESS, run for multiple climate change scenarios through the year 2100. We projected potential changes in reproduction based on an empirical relationship between spring precipitation and the mean number of successful fledglings produced per nest attempt. As modeled in our study, climate change had virtually no effect on the RCW population. Conversely, simulated effects of land-use change resulted in the loss of up to 28 breeding pairs by 2100. However, the simulated impacts of development depended on where the development occurred and could be completely avoided if the new training areas were placed in poor-quality habitat. Our results demonstrate the flexibility inherent in many systems that allows seemingly incompatible human land uses, such as development, and conservation actions to exist side by side.

  14. Boreal forests can have a remarkable role in reducing greenhouse gas emissions locally: Land use-related and anthropogenic greenhouse gas emissions and sinks at the municipal level.

    Science.gov (United States)

    Vanhala, Pekka; Bergström, Irina; Haaspuro, Tiina; Kortelainen, Pirkko; Holmberg, Maria; Forsius, Martin

    2016-07-01

    Ecosystem services have become an important concept in policy-making. Carbon (C) sequestration into ecosystems is a significant ecosystem service, whereas C losses can be considered as an ecosystem disservice. Municipalities are in a position to make decisions that affect local emissions and therefore are important when considering greenhouse gas (GHG) mitigation. Integrated estimations of fluxes at a regional level help local authorities to develop land use policies for minimising GHG emissions and maximising C sinks. In this study, the Finnish national GHG accounting system is modified and applied at the municipal level by combining emissions and sinks from agricultural land, forest areas, water bodies and mires (land use-related GHG emissions) with emissions from activities such as energy production and traffic (anthropogenic GHG emissions) into the LUONNIKAS calculation tool. The study area consists of 14 municipalities within the Vanajavesi catchment area located in Southern Finland. In these municipalities, croplands, peat extraction sites, water bodies and undrained mires are emission sources, whereas forests are large carbon sinks that turn the land use-related GHG budget negative, resulting in C sequestration into the ecosystem. The annual land use-related sink in the study area was 78tCO2eqkm(-2) and 2.8tCO2eq per capita. Annual anthropogenic GHG emissions from the area amounted to 250tCO2eqkm(-2) and 9.2tCO2eq per capita. Since forests are a significant carbon sink and the efficiency of this sink is heavily affected by forest management practices, forest management policy is a key contributing factor for mitigating municipal GHG emissions. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Tropospheric sampling with aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Daum, P.H.; Springston, S.R.

    1991-03-01

    Aircraft constitute a unique environment which places stringent requirements on the instruments used to measure the concentrations of atmospheric trace gases and aerosols. Some of these requirements such as minimization of size, weight, and power consumption are general; others are specific to individual techniques. This review presents the basic principles and considerations governing the deployment of trace gas and aerosol instrumentation on an aircraft. An overview of common instruments illustrates these points and provides guidelines for designing and using instruments on aircraft-based measurement programs.

  16. SOLAR AIRCRAFT DESIGN

    OpenAIRE

    RAHMATI, Sadegh; GHASED, Amir

    2015-01-01

    Abstract. Generally domain Aircraft uses conventional fuel. These fuel having limited life, high cost and pollutant. Also nowadays price of petrol and other fuels are going to be higher, because of scarcity of those fuels. So there is great demand of use of non-exhaustible unlimited source of energy like solar energy. Solar aircraft is one of the ways to utilize solar energy. Solar aircraft uses solar panel to collect the solar radiation for immediate use but it also store the remaining part ...

  17. Application of variable structure system theory to aircraft flight control. [AV-8A and the Augmentor Wing Jet STOL Research Aircraft

    Science.gov (United States)

    Calise, A. J.; Kadushin, I.; Kramer, F.

    1981-01-01

    The current status of research on the application of variable structure system (VSS) theory to design aircraft flight control systems is summarized. Two aircraft types are currently being investigated: the Augmentor Wing Jet STOL Research Aircraft (AWJSRA), and AV-8A Harrier. The AWJSRA design considers automatic control of longitudinal dynamics during the landing phase. The main task for the AWJSRA is to design an automatic landing system that captures and tracks a localizer beam. The control task for the AV-8A is to track velocity commands in a hovering flight configuration. Much effort was devoted to developing computer programs that are needed to carry out VSS design in a multivariable frame work, and in becoming familiar with the dynamics and control problems associated with the aircraft types under investigation. Numerous VSS design schemes were explored, particularly for the AWJSRA. The approaches that appear best suited for these aircraft types are presented. Examples are given of the numerical results currently being generated.

  18. Integrated spatiotemporal modelling of bioenergy production potentials, agricultural land use, and related GHG balances; demonstrated for Ukraine

    NARCIS (Netherlands)

    van der Hilst, Floortje; Verstegen, Judith A.; Zheliezna, Tetiana; Drozdova, Olga; Faaij, André P C

    2014-01-01

    This study shows how bioenergy potential and total greenhouse gas (GHG) balances of land-use change and agricultural intensification can be modeled in an integrated way. The modeling framework is demonstrated for first- and second-generation ethanol production in Ukraine for the timeframe 2010-2030

  19. Growth response of Pterocarpus soyauxii and Lophira alata seedlings to host soil mycorrhizal inocula in relation to land use types.

    NARCIS (Netherlands)

    Onguene, N.A.; Ngonkeu, L.E.M.; Kuyper, T.W.

    2011-01-01

    Deficiency in mycorrhizal inoculum in soils due to land use types (LUT) can be alleviated by quantity and quality inoculum addition. A bioassay was carried out to determine how host soil mycorrhizal inoculum influenced mycorrhizal colonization, carbon allocation and partitioning of seedlings of two

  20. 'Waar gaan ons heen van hier?': The struggle between autonomy and relationality in Antjie Krog's "land van genade en verdriet"

    NARCIS (Netherlands)

    Stuit, H.; Jansen, E.

    2011-01-01

    Antjie Krog's cycle of poems entitled "land van genade en verdriet" in Kleur kom nooit alleen nie (2000) tracks and problematises the repercussions of a process of reconciliation by foregrounding issues of guilt, space, language and the desire and difficulty to start anew. Krog's treatment of the ab

  1. Growth response of Pterocarpus soyauxii and Lophira alata seedlings to host soil mycorrhizal inocula in relation to land use types.

    NARCIS (Netherlands)

    Onguene, N.A.; Ngonkeu, L.E.M.; Kuyper, T.W.

    2011-01-01

    Deficiency in mycorrhizal inoculum in soils due to land use types (LUT) can be alleviated by quantity and quality inoculum addition. A bioassay was carried out to determine how host soil mycorrhizal inoculum influenced mycorrhizal colonization, carbon allocation and partitioning of seedlings of two

  2. Analyzing changes in the beef cattle ranching communities of acatic and tepatitlan de morelos, jalisco, Mexico related to land cover and climate variability

    Science.gov (United States)

    Trevino-Pena, Melva B.

    shrub land category of about 430 ha and a decrease in the crop land category of about 690 ha. To gain insight into the effects of climate variability on the livelihoods of these communities, nine local beef cattle ranchers were interviewed on a one-on-one basis. All participants believe that the local beef cattle industry is highly valuable to the economy and culture of the region. All participants also mentioned that notable variations in to the climate have been occurring in recent decades; mainly precipitation scarcity and higher temperatures. The locals believe that these changes are the result of extensive deforestation. In past decades, deforestation of native vegetation has been intensely performed in order to make land available for agricultural purposes. Therefore, among the various adaptation measures to the changes presented in the climate, the cattle ranchers talked about planting trees. People believe that the "vision" of the region is changing and that reforestation has become a priority in this land. To determine the exact causes of the climate changes experienced in this region, further investigations have to be done. However, it is certain that these changes are having implications on the economic activities of the region; the people of these communities will continue facing difficulties if the present changes in the regional climate continue to develop. The employment of proper adaptation measures has the potential to reduce climate-related losses within the livestock and agricultural sectors. Therefore, it is crucial that preventive measures are taken by the members of these communities before the effects of climate change worsen in the region.

  3. Building Toward an Unmanned Aircraft System Training Strategy

    Science.gov (United States)

    2014-01-01

    Yes Orchard range Yes, UAS operations are limited to using r-3203. Fixed support facilities UAS operations. Facilities will be in range Complex...system, two tactical automatic landing systems, and ground support equipment. In total, the program will be 124 aircraft, plus 21 attrition...The Shadow is catapulted from a rail-launcher, and recovered with the aid of arresting gear. The UAS also possesses automatic takeoff and landing

  4. Influence of environmental factors on corrosion damage of aircraft structure

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Corrosion is one of the important structural integrity concerns of aging aircraft, and it is estimated that a significant portion of airframe maintenance budgets is directed towards corrosion-related problems for both military and commercial aircraft. In order to better understand how environmental factors influence the corrosion damage initiation and propagation on aircraft structure and to predict pre-corrosion test pieces of fatigue life and structural integrity of an effective approach, this paper uses ...

  5. Essentials of aircraft armaments

    CERN Document Server

    Kaushik, Mrinal

    2017-01-01

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

  6. Aircraft Fire Protection Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Navy Aircraft Protection Laboratory provides complete test support for all Navy air vehicle fire protection systems. The facility allows for the simulation of a...

  7. Aircraft Fire Protection Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Navy Aircraft Protection Laboratory provides complete test support for all Navy air vehicle fire protection systems.The facility allows for the simulation of a...

  8. 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.

  9. Depreciation of aircraft

    Science.gov (United States)

    Warner, Edward P

    1922-01-01

    There is a widespread, and quite erroneous, impression to the effect that aircraft are essentially fragile and deteriorate with great rapidity when in service, so that the depreciation charges to be allowed on commercial or private operation are necessarily high.

  10. Comparison of regression models with land-use and emissions data to predict the spatial distribution of traffic-related air pollution in Rome.

    Science.gov (United States)

    Rosenlund, Mats; Forastiere, Francesco; Stafoggia, Massimo; Porta, Daniela; Perucci, Mara; Ranzi, Andrea; Nussio, Fabio; Perucci, Carlo A

    2008-03-01

    Spatial modeling of traffic-related air pollution typically involves either regression modeling of land-use and traffic data or dispersion modeling of emissions data, but little is known to what extent land-use regression models might be improved by incorporating emissions data. The aim of this study was to develop a land-use regression model to predict nitrogen dioxide (NO2) concentrations and compare its performance with a model including emissions data. The association between each land-use variable and NO2 concentrations at 68 locations in Rome in 1995 and 1996 was assessed by univariate linear regression and a multiple linear regression model that was constructed based on the importance of each variable. Traffic emissions (particulate matter, carbon monoxide, nitrogen oxides, and benzene) were estimated for 164 areas of the city based on vehicle type, traffic counts and driving patterns. Mean NO2 concentration across the 68 sites was 46.8 microg/m3 (SD 9.8 microg/m3; inter-quartile range 11.5 microg/m3; min 24 microg/m3; max 73 microg/m3). The most important predicting variables were the circular traffic zones (main ring road, green strip, inner ring road, traffic-limited zone), distance from busy streets, size of the census block, the inverse population density, and altitude. A multiple regression model including these variables resulted in an R2 of 0.686. The best-fitting model adding an emission term of benzene resulted in an R2 of 0.690, but was not significantly different from the model without emissions (P=0.147). In conclusion, these results suggest that a land-use regression model explains the traffic-related air pollution levels with reasonable accuracy and that emissions data do not significantly improve the model.

  11. Land valuation and marginalization processes in cultural landscapes - a comparative study of valuation systems related to natural and semi-natural areas

    DEFF Research Database (Denmark)

    Christensen, Andreas Aagaard; Svenningsen, Stig Roar; Brandt, Jesper

    2012-01-01

    of a comparative analysis of expert-based valuations and local conceptions of natural value will be presented. Possible points of intersection between the two approaches will be identified, and it will be discussed how the two valuation systems relate to each other and correlate with patterns of land use and land...... parallel approaches to how such valuations are developed and transformed into policy seems to exist: (1) A "bottom-up" approach, in which collaborative and locally experienced perspectives on the landscape are considered primary, and (2) A "top-down" approach relying on biological, landscape ecological...... and other types of expert-based designations of historical, natural, scenic and biodiversity-related values in the landscape. While both of these approaches reflect real aspects of the landscapes they are used to valuate, they represent two essentially different conceptions of how regulation and designation...

  12. Soil Fertility in relation to Landscape Position and Land Use/Cover Types: A Case Study of the Lake Kivu Pilot Learning Site

    Directory of Open Access Journals (Sweden)

    Majaliwa Mwanjalolo Jackson-Gilbert

    2015-01-01

    Full Text Available This study determined the change and distribution of land-uses/covers along the landscape, and evaluated the nutrient status of the top soil layer in the Lake Kivu Pilot Learning Site (LKPLS benchmarked micro-catchments. Soil physical and chemical properties were quantified using triplicate soil samples collected from each land-use/cover at two depths (0–15 and 15–30 cm in three LK PLS Learning Innovation Platform (IP sites (Bufundi in Uganda, Mupfuni-Shanga in D.R. Congo, Gataraga in Rwanda. Small scale agriculture has increased in all the benchmarked micro-catchments at the expense of other land-uses/covers. In the settlement areas land-use/cover distribution along the landscape varied across sites and countries; the major one being eucalyptus woodlots, wetland, and perennials and annuals crops in Bufundi; annuals and perennials crops in Mupfuni-Shanga; and annuals crops in Gataraga. Perennial crops tended to occur at the footslope and valley bottoms, while the annuals occurred at the upper backslopes and summits. Available P and K were relatively higher and C/N ratio (7.28 was the lowest in Mupfuni Shanga. Annual crops had the lowest available P and N across site (P<0.05. The key nutrients N, P and K were below the critical values for plant growth for Bufundi.

  13. Automatic aircraft recognition

    Science.gov (United States)

    Hmam, Hatem; Kim, Jijoong

    2002-08-01

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

  14. Ground-Based Calibration Of A Microwave Landing System

    Science.gov (United States)

    Kiriazes, John J.; Scott, Marshall M., Jr.; Willis, Alfred D.; Erdogan, Temel; Reyes, Rolando

    1996-01-01

    System of microwave instrumentation and data-processing equipment developed to enable ground-based calibration of microwave scanning-beam landing system (MSBLS) at distances of about 500 to 1,000 ft from MSBLS transmitting antenna. Ensures accuracy of MSBLS near touchdown point, without having to resort to expense and complex logistics of aircraft-based testing. Modified versions prove useful in calibrating aircraft instrument landing systems.

  15. Analysis on the Dynamic Characteristics of Carrier-based Aircraft Nose Landing Gear with Sudden Holdback Load Discharge%舰载机弹射起飞前起落架牵制载荷突卸动力学分析

    Institute of Scientific and Technical Information of China (English)

    于浩; 聂宏; 魏小辉

    2011-01-01

    舰载机弹射起飞过程中,由于牵制载荷突卸而产生的前起落架沿航向的快速振动会给机体结构和设备都带来严重的疲劳问题,为研究该振动现象并提出解决方案,建立了舰载机弹射起飞动力学模型,分析计算了前起落架的受载情况,并详细论述其动力学成因,推导了消除前起落架振动现象的充分必要条件.研究结果表明:牵制载荷沿下扭力臂轴向的载荷分量所造成的缓冲器活塞杆的向后弯曲是导致牵制载荷突卸后前起落架振动的主要原因;牵制载荷突卸后,起落架的前后振动导致起落架与机身铰接处的载荷快速、大幅的振荡,对机体结构以及机载设备的寿命和使用安全都会产生不利影响;牵制杆的长度直接影响牵制载荷沿下扭力臂轴向的载荷分量,降低该载荷分量可以有效地解决前起落架由于牵制载荷突卸所带来的振动问题.%The vibration of a nose landing gear caused by the sudden discharge of holdback load during the catapult launch of a carrier-based aircraft could bring serious fatigue both to the structure of the launch and the airborne equipment. To investigate the vibration and seek a solution, a dynamic model of the catapult launch is established. The load of the nose landing gear is calculated, while the kinetics and the way to deal with the phenomenon is also discussed in detail. From the catapult launch calculation, three important conclusions are obtained: during the tension stage, there is a long stroke and aft bending of the nose landing gear; once the holdback load suddenly discharges, the landing gear strut extends and springs forward rapidly; the fore-aft vibration of the nose landing gear produces a rapid and drastic load change at the joint of the gear and the fuselage. This vibration load has an adverse effect on the life and safety of the structure and the equipment of the aircraft. The length of the holdback bar influences the load

  16. Approach Considerations in Aircraft with High-Lift Propeller Systems

    Science.gov (United States)

    Patterson, Michael D.; Borer, Nicholas K.

    2017-01-01

    NASA's research into distributed electric propulsion (DEP) includes the design and development of the X-57 Maxwell aircraft. This aircraft has two distinct types of DEP: wingtip propellers and high-lift propellers. This paper focuses on the unique opportunities and challenges that the high-lift propellers--i.e., the small diameter propellers distributed upstream of the wing leading edge to augment lift at low speeds--bring to the aircraft performance in approach conditions. Recent changes to the regulations related to certifying small aircraft (14 CFR x23) and these new regulations' implications on the certification of aircraft with high-lift propellers are discussed. Recommendations about control systems for high-lift propeller systems are made, and performance estimates for the X-57 aircraft with high-lift propellers operating are presented.

  17. Characterization and Feasibility Assessment of Recycled Paper Mill Sludges for Land Application in Relation to the Environment

    OpenAIRE

    Rosazlin Abdullah; Che Fauziah Ishak; Wan Rasidah Kadir; Rosenani Abu Bakar

    2015-01-01

    The disposal of industrial paper mill sludge waste is a big issue and has a great importance all over the world. A study was conducted to determine the chemical properties of recycled paper mill sludge (RPMS) and assess its possibilities for land application. RPMS samples were collected from six different paper mills in Malaysia and analyzed for physical and chemical properties, heavy metals, polycyclic aromatic hydrocarbons, 13C-NMR spectra and for the presence of dioxins/furans. The RPMS w...

  18. Changes of soil carbon dioxide, methane, and nitrous oxide fluxes in relation to land use/cover management.

    Science.gov (United States)

    Kooch, Yahya; Moghimian, Negar; Bayranvand, Mohammad; Alberti, Giorgio

    2016-06-01

    Conversions of land use/cover are associated with changes in soil properties and biogeochemical cycling, with implications for carbon (C), nitrogen (N), and trace gas fluxes. In an attempt to provide a comprehensive evaluation of the significance of different land uses (Alnus subcordata plantation, Taxodium distichum plantation, agriculture, and deforested areas) on soil features and on the dynamics of greenhouse gas (GHG) fluxes at local scale, this study was carried out in Mazandaran province, northern Iran. Sixteen samples per land use, from the top 10 cm of soil, were taken, from which bulk density, texture, water content, pH, organic C, total N, microbial biomass of C and N, and earthworm density/biomass were determined. In addition, the seasonal changes in the fluxes of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) were monitored over a year. Our results indicated that the different land uses were different in terms of soil properties and GHG fluxes. Even though the amount of the GHG varied widely during the year, the highest CO2 and CH4 fluxes (0.32 mg CO2 m(-2) day(-1) and 0.11 mg CH4 m(-2) day(-1), respectively) were recorded in the deforested areas. N2O flux was higher in Alnus plantation (0.18 mg N2O m(-2) day(-1)) and deforested areas (0.17 mg N2O m(-2) day(-1)) than at agriculture site (0.05 mg N2O m(-2) day(-1)) and Taxodium plantation (0.03 mg N2O m(-2) day(-1)). This study demonstrated strong impacts of land use change on soil-atmosphere trace gas exchanges and provides useful observational constraints for top-down and bottom-up biogeochemistry models.

  19. Using aircraft as wind sensors for estimating accurate wind fields for air traffic management applications

    OpenAIRE

    Hernando Guadaño, Laura; Arnaldo Valdes, Rosa Maria; Saez Nieto, Francisco Javier

    2014-01-01

    A study which examines the use of aircraft as wind sensors in a terminal area for real-time wind estimation in order to improve aircraft trajectory prediction is presented in this paper. We describe not only different sources in the aircraft systems that provide the variables needed to derivate the wind velocity but the capabilities which allow us to present this information for ATM Applications. Based on wind speed samples from aircraft landing at Madrid-Barajas airport, a real-time wind fie...

  20. Spatial Analysis of Soil Subsidence in Peat Meadow Areas in Friesland in Relation to Land and Water Management, Climate Change, and Adaptation

    Science.gov (United States)

    Brouns, Karlijn; Eikelboom, Tessa; Jansen, Peter C.; Janssen, Ron; Kwakernaak, Cees; van den Akker, Jan J. H.; Verhoeven, Jos T. A.

    2015-02-01

    Dutch peatlands have been subsiding due to peat decomposition, shrinkage and compression, since their reclamation in the 11th century. Currently, subsidence amounts to 1-2 cm/year. Water management in these areas is complex and costly, greenhouse gases are being emitted, and surface water quality is relatively poor. Regional and local authorities and landowners responsible for peatland management have recognized these problems. In addition, the Netherlands Royal Meteorological Institute predicts higher temperatures and drier summers, which both are expected to enhance peat decomposition. Stakeholder workshops have been organized in three case study areas in the province of Friesland to exchange knowledge on subsidence and explore future subsidence rates and the effects of land use and management changes on subsidence rates. Subsidence rates were up to 3 cm/year in deeply drained parcels and increased when we included climate change in the modeling exercises. This means that the relatively thin peat layers in this province (ca 1 m) would shrink or even disappear by the end of the century when current practices continue. Adaptation measures were explored, such as extensive dairy farming and the production of new crops in wetter conditions, but little experience has been gained on best practices. The workshops have resulted in useful exchange of ideas on possible measures and their consequences for land use and water management in the three case study areas. The province and the regional water board will use the results to develop land use and water management policies for the next decades.

  1. Spatial analysis of soil subsidence in peat meadow areas in Friesland in relation to land and water management, climate change, and adaptation.

    Science.gov (United States)

    Brouns, Karlijn; Eikelboom, Tessa; Jansen, Peter C; Janssen, Ron; Kwakernaak, Cees; van den Akker, Jan J H; Verhoeven, Jos T A

    2015-02-01

    Dutch peatlands have been subsiding due to peat decomposition, shrinkage and compression, since their reclamation in the 11th century. Currently, subsidence amounts to 1-2 cm/year. Water management in these areas is complex and costly, greenhouse gases are being emitted, and surface water quality is relatively poor. Regional and local authorities and landowners responsible for peatland management have recognized these problems. In addition, the Netherlands Royal Meteorological Institute predicts higher temperatures and drier summers, which both are expected to enhance peat decomposition. Stakeholder workshops have been organized in three case study areas in the province of Friesland to exchange knowledge on subsidence and explore future subsidence rates and the effects of land use and management changes on subsidence rates. Subsidence rates were up to 3 cm/year in deeply drained parcels and increased when we included climate change in the modeling exercises. This means that the relatively thin peat layers in this province (ca 1 m) would shrink or even disappear by the end of the century when current practices continue. Adaptation measures were explored, such as extensive dairy farming and the production of new crops in wetter conditions, but little experience has been gained on best practices. The workshops have resulted in useful exchange of ideas on possible measures and their consequences for land use and water management in the three case study areas. The province and the regional water board will use the results to develop land use and water management policies for the next decades.

  2. The Emergency Landing Planner Experiment

    Science.gov (United States)

    Meuleau, Nocolas F.; Neukom, Christian; Plaunt, Christian John; Smith, David E.; Smith, Tristan B.

    2011-01-01

    In previous work, we described an Emergency Landing Planner (ELP) designed to assist pilots in choosing the best emergency landing site when damage or failures occur in an aircraft. In this paper, we briefly describe the system, but focus on the integration of this system into the cockpit of a 6 DOF full-motion simulator and a study designed to evaluate the ELP. We discuss the results of this study, the lessons learned, and some of the issues involved in advancing this work further.

  3. Differences in Characteristics of Aviation Accidents During 1993-2012 Based on Aircraft Type

    Science.gov (United States)

    Evans, Joni K.

    2015-01-01

    Civilian aircraft are available in a variety of sizes, engine types, construction materials and instrumentation complexity. For the analysis reported here, eleven aircraft categories were developed based mostly on aircraft size and engine type, and these categories were applied to twenty consecutive years of civil aviation accidents. Differences in various factors were examined among these aircraft types, including accident severity, pilot characteristics and accident occurrence categories. In general, regional jets and very light sport aircraft had the lowest rates of adverse outcomes (injuries, fatal accidents, aircraft destruction, major accidents), while aircraft with twin (piston) engines or with a single (piston) engine and retractable landing gear carried the highest incidence of adverse outcomes. The accident categories of abnormal runway contact, runway excursions and non-powerplant system/component failures occur frequently within all but two or three aircraft types. In contrast, ground collisions, loss of control - on ground/water and powerplant system/component failure occur frequently within only one or two aircraft types. Although accidents in larger aircraft tend to have less severe outcomes, adverse outcome rates also differ among accident categories. It may be that the type of accident has as much or more influence on the outcome as the type of aircraft.

  4. Variation of avifaunal diversity in relation to land-use modifications around a tropical estuary, the Negombo estuary in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Manjari Bhagya Jayathilake

    2015-03-01

    Full Text Available We assessed variation in avifaunal diversity at some selected habitats around the Negombo estuary in Sri Lanka in relation to land-use modifications. During the study period, we observed 48 bird species of which 47 species are residents to Sri Lanka. The avian species richness, evenness, and heterogeneity were found to be the highest at undisturbed habitats. Further, these diversity measures were negatively correlated with the intensity of anthropogenic land-use activities. Total abundance of birds increased at highly disturbed habitats due to the presence of the house crow, as it is the most abundant of all birds observed at these habitats. This study highlights the need for habitat management around estuaries, giving due consideration to existing ecological theories to conserve avifaunal diversity. It also highlights the negative impacts of the house crow on diversity of other resident avian fauna in these habitats.

  5. A Grounded Theory Study of Aircraft Maintenance Technician Decision-Making

    Science.gov (United States)

    Norcross, Robert

    Aircraft maintenance technician decision-making and actions have resulted in aircraft system errors causing aircraft incidents and accidents. Aircraft accident investigators and researchers examined the factors that influence aircraft maintenance technician errors and categorized the types of errors in an attempt to prevent similar occurrences. New aircraft technology introduced to improve aviation safety and efficiency incur failures that have no information contained in the aircraft maintenance manuals. According to the Federal Aviation Administration, aircraft maintenance technicians must use only approved aircraft maintenance documents to repair, modify, and service aircraft. This qualitative research used a grounded theory approach to explore the decision-making processes and actions taken by aircraft maintenance technicians when confronted with an aircraft problem not contained in the aircraft maintenance manuals. The target population for the research was Federal Aviation Administration licensed aircraft and power plant mechanics from across the United States. Nonprobability purposeful sampling was used to obtain aircraft maintenance technicians with the experience sought in the study problem. The sample population recruitment yielded 19 participants for eight focus group sessions to obtain opinions, perceptions, and experiences related to the study problem. All data collected was entered into the Atlas ti qualitative analysis software. The emergence of Aircraft Maintenance Technician decision-making themes regarding Aircraft Maintenance Manual content, Aircraft Maintenance Technician experience, and legal implications of not following Aircraft Maintenance Manuals surfaced. Conclusions from this study suggest Aircraft Maintenance Technician decision-making were influenced by experience, gaps in the Aircraft Maintenance Manuals, reliance on others, realizing the impact of decisions concerning aircraft airworthiness, management pressures, and legal concerns

  6. Identification of Aircraft Hazards

    Energy Technology Data Exchange (ETDEWEB)

    K. Ashley

    2006-12-08

    Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2005 [DIRS 174235], Section 6.4.1). That determination was conservatively based upon limited knowledge of flight data in the area of concern and upon crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a monitored geologic repository (MGR) at Yucca Mountain, using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987 [DIRS 103124], Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. The intended use of this report is to provide inputs for further screening and analysis of identified aircraft hazards based upon the criteria that apply to Category 1 and Category 2 event sequence analyses as defined in 10 CFR 63.2 [DIRS 176544] (Section 4). The scope of this report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the repository at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after consideration of applicable screening criteria (Section 7).

  7. IDENTIFICATION OF AIRCRAFT HAZARDS

    Energy Technology Data Exchange (ETDEWEB)

    K.L. Ashley

    2005-03-23

    Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in the ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2004, Section 6.4.1). That determination was conservatively based on limited knowledge of flight data in the area of concern and on crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a Monitored Geologic Repository (MGR) at Yucca Mountain using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987, Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. NUREG-0800 is being used here as a reference because some of the same considerations apply. The intended use of this report is to provide inputs for further screening and analysis of the identified aircraft hazards based on the criteria that apply to Category 1 and 2 event sequence analyses as defined in 10 CFR 63.2 (see Section 4). The scope of this technical report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the MGR at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after consideration of applicable screening criteria (see Section 7).

  8. 77 FR 24251 - Consensus Standards, Light-Sport Aircraft

    Science.gov (United States)

    2012-04-23

    ... Federal Aviation Administration Consensus Standards, Light-Sport Aircraft AGENCY: Federal Aviation... availability of three new and three revised consensus standards relating to the provisions of the Sport Pilot and Light-Sport Aircraft rule issued July 16, 2004, and effective September 1, 2004....

  9. 78 FR 35085 - Consensus Standards, Light-Sport Aircraft

    Science.gov (United States)

    2013-06-11

    ... Federal Aviation Administration Consensus Standards, Light-Sport Aircraft AGENCY: Federal Aviation... availability of one new and seven revised consensus standards relating to the provisions of the Sport Pilot and Light-Sport Aircraft rule issued July 16, 2004, and effective September 1, 2004. ASTM...

  10. Modelling carbon dynamics from urban land conversion: fundamental model of city in relation to a local carbon cycle

    Directory of Open Access Journals (Sweden)

    Schellnhuber Hans-Joachim

    2006-08-01

    Full Text Available Abstract Background The main task is to estimate the qualitative and quantitative contribution of urban territories and precisely of the process of urbanization to the Global Carbon Cycle (GCC. Note that, on the contrary to many investigations that have considered direct anthropogenic emission of CO2(urbanized territories produce ca. 96–98% of it, we are interested in more subtle, and up until the present time, weaker processes associated with the conversion of the surrounding natural ecosystems and landscapes into urban lands. Such conversion inevitably takes place when cities are sprawling and additional "natural" lands are becoming "urbanized". Results In order to fulfil this task, we first develop a fundamental model of urban space, since the type of land cover within a city makes a difference for a local carbon cycle. Hence, a city is sub-divided by built-up, „green" (parks, etc. and informal settlements (favelas fractions. Another aspect is a sub-division of the additional two regions, which makes the total number reaching eight regions, while the UN divides the world by six. Next, the basic model of the local carbon cycle for urbanized territories is built. We consider two processes: carbon emissions as a result of conversion of natural lands caused by urbanization; and the transformation of carbon flows by "urbanized" ecosystems; when carbon, accumulated by urban vegetation, is exported to the neighbouring territories. The total carbon flow in the model depends, in general, on two groups of parameters. The first includes the NPP, and the sum of living biomass and dead organic matter of ecosystems involved in the process of urbanization, and namely them we calculate here, using a new more realistic approach and taking into account the difference in regional cities' evolution. Conclusion There is also another group of parameters, dealing with the areas of urban territories, and their annual increments. A method of dynamic forecasting

  11. Land Cover

    Data.gov (United States)

    Kansas Data Access and Support Center — The Land Cover database depicts 10 general land cover classes for the State of Kansas. The database was compiled from a digital classification of Landsat Thematic...

  12. Land acquisition

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of lands acquired by Neal Smith National Wildlife Refuge between 1991 and 2009. Lists of acres and locations of land acquired are provided for...

  13. Boreal forests can have a remarkable role in reducing greenhouse gas emissions locally: Land use-related and anthropogenic greenhouse gas emissions and sinks at the municipal level

    Energy Technology Data Exchange (ETDEWEB)

    Vanhala, Pekka, E-mail: pekka.vanhala@ymparisto.fi [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland); Bergström, Irina [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland); Haaspuro, Tiina [University of Helsinki, Department of Environmental Sciences, P.O. Box 65, Viikinkaari 1, 00014 Helsinki (Finland); Kortelainen, Pirkko; Holmberg, Maria; Forsius, Martin [Finnish Environment Institute, Natural Environment Centre, P.O. Box 140, Mechelininkatu 34 a, FI-00251 Helsinki (Finland)

    2016-07-01

    Ecosystem services have become an important concept in policy-making. Carbon (C) sequestration into ecosystems is a significant ecosystem service, whereas C losses can be considered as an ecosystem disservice. Municipalities are in a position to make decisions that affect local emissions and therefore are important when considering greenhouse gas (GHG) mitigation. Integrated estimations of fluxes at a regional level help local authorities to develop land use policies for minimising GHG emissions and maximising C sinks. In this study, the Finnish national GHG accounting system is modified and applied at the municipal level by combining emissions and sinks from agricultural land, forest areas, water bodies and mires (land use-related GHG emissions) with emissions from activities such as energy production and traffic (anthropogenic GHG emissions) into the LUONNIKAS calculation tool. The study area consists of 14 municipalities within the Vanajavesi catchment area located in Southern Finland. In these municipalities, croplands, peat extraction sites, water bodies and undrained mires are emission sources, whereas forests are large carbon sinks that turn the land use-related GHG budget negative, resulting in C sequestration into the ecosystem. The annual land use-related sink in the study area was 78 t CO{sub 2} eq km{sup −2} and 2.8 t CO{sub 2} eq per capita. Annual anthropogenic GHG emissions from the area amounted to 250 t CO{sub 2} eq km{sup −2} and 9.2 t CO{sub 2} eq per capita. Since forests are a significant carbon sink and the efficiency of this sink is heavily affected by forest management practices, forest management policy is a key contributing factor for mitigating municipal GHG emissions. - Highlights: • The significance of natural landscapes in the regional C budgets is shown. • Boreal forests can be remarkable C sinks enabling net C sequestration in ecosystems. • The large area of forest may compensate for all C emissions in the municipality.

  14. Mulighedernes land?

    DEFF Research Database (Denmark)

    Munck Petersen, Rikke

    2001-01-01

    Kommentar om arbejde med det åbne land i forlængelse af konfencen "Mulighedernes land" og vigtigheden af at landskabsarkitekter går aktivt ind i debatten og arbejdet med landskabets forandring i Danmark.......Kommentar om arbejde med det åbne land i forlængelse af konfencen "Mulighedernes land" og vigtigheden af at landskabsarkitekter går aktivt ind i debatten og arbejdet med landskabets forandring i Danmark....

  15. Quantifying sample biases of inland lake sampling programs in relation to lake surface area and land use/cover.

    Science.gov (United States)

    Wagner, Tyler; Soranno, Patricia A; Cheruvelil, Kendra Spence; Renwick, William H; Webster, Katherine E; Vaux, Peter; Abbitt, Robbyn J F

    2008-06-01

    We quantified potential biases associated with lakes monitored using non-probability based sampling by six state agencies in the USA (Michigan, Wisconsin, Iowa, Ohio, Maine, and New Hampshire). To identify biases, we compared state-monitored lakes to a census population of lakes derived from the National Hydrography Dataset. We then estimated the probability of lakes being sampled using generalized linear mixed models. Our two research questions were: (1) are there systematic differences in lake area and land use/land cover (LULC) surrounding lakes monitored by state agencies when compared to the entire population of lakes? and (2) after controlling for the effects of lake size, does the probability of sampling vary depending on the surrounding LULC features? We examined the biases associated with surrounding LULC because of the established links between LULC and lake water quality. For all states, we found that larger lakes had a higher probability of being sampled compared to smaller lakes. Significant interactions between lake size and LULC prohibit us from drawing conclusions about the main effects of LULC; however, in general lakes that are most likely to be sampled have either high urban use, high agricultural use, high forest cover, or low wetland cover. Our analyses support the assertion that data derived from non-probability-based surveys must be used with caution when attempting to make generalizations to the entire population of interest, and that probability-based surveys are needed to ensure unbiased, accurate estimates of lake status and trends at regional to national scales.

  16. Aircraft noise reduction technology. [to show impact on individuals and communities, component noise sources, and operational procedures to reduce impact

    Science.gov (United States)

    1973-01-01

    Aircraft and airport noise reduction technology programs conducted by NASA are presented. The subjects discussed are: (1) effects of aircraft noise on individuals and communities, (2) status of aircraft source noise technology, (3) operational procedures to reduce the impact of aircraft noise, and (4) NASA relations with military services in aircraft noise problems. References to more detailed technical literature on the subjects discussed are included.

  17. Relation of water quality to land use in the drainage basins of six tributaries to the lower Delaware River, New Jersey, 2002-07

    Science.gov (United States)

    Baker, Ronald J.; Esralew, Rachel A.

    2010-01-01

    Concentrations and loads of water-quality constituents in six streams in the lower Delaware River Basin of New Jersey were determined in a multi-year study conducted by the U.S. Geological Survey, in cooperation with the New Jersey Department of Environmental Protection. Two streams receive water from relatively undeveloped basins, two from largely agricultural basins, and two from heavily urbanized basins. Each stream was monitored during eight storms and at least eight times during base flow during 2002-07. Sampling was conducted during base flow before each storm, when stage was first observed to rise, and several times during the rising limb of the hydrographs. Agricultural and urban land use has resulted in statistically significant increases in loads of nitrogen and phosphorus species relative to loads in undeveloped basins. For example, during the growing season, median storm flow concentrations of total nitrogen in the two streams in agricultural areas were 6,290 and 1,760 mg/L, compared to 988 and 823 mg/L for streams in urban areas, and 719 and 333 mg/L in undeveloped areas. Although nutrient concentrations and loads were clearly related to land useurban, agricultural, and undeveloped within the drainage basins, other basin characteristics were found to be important. Residual nutrients entrapped in lake sediments from streams that received effluent from recently removed sewage-treatment plants are hypothesized to be the cause of extremely high levels of nutrient loads to one urban stream, whereas another urban stream with similar land-use percentages (but without the legacy of sewage-treatment plants) had much lower levels of nutrients. One of the two agricultural streams studied had higher nutrient loads than the other, especially for total phosphorous and organic nitrogen. This difference appears to be related to the presence (or absence) of livestock (cattle).

  18. Advanced Aircraft Material

    Directory of Open Access Journals (Sweden)

    Vivek Kumar Prince

    2013-06-01

    Full Text Available There has been long debate on “advanced aircraft material” from past decades & researchers too came out with lots of new advanced material like composites and different aluminum alloys. Now days a new advancement that is in great talk is third generation Aluminum-lithium alloy. Newest Aluminum-lithium alloys are found out to have low density, higher elastic modulus, greater stiffness, greater cryogenic toughness, high resistance to fatigue cracking and improved corrosion resistance properties over the earlier used aircraft material as mentioned in Table 3 [1-5]. Comparison had been made with nowadays used composite material and is found out to be more superior then that

  19. AIRCRAFT MAINTENANCE HANGAR

    Directory of Open Access Journals (Sweden)

    GEAMBASU Gabriel George

    2017-05-01

    Full Text Available The paper presents the maintenance process that is done on an airplane, at a certain period of time, or after a number of flight hours or cycles and describes the checks performed behind each inspection. The first part of research describes the aircraft maintenance process that has to be done after an updated maintenance manual according with aircraft type, followed by a short introduction about maintenance hangar. The second part of the paper presents a hangar design with a foldable roof and walls, which can be folded or extended, over an airplane when a maintenance process is done, or depending on weather condition.

  20. Genesis of the Lunar Landing Vehicle

    Science.gov (United States)

    Gelzer, Christian

    2009-01-01

    The author examines early research regarding return flight from a Moon landing made prior to President Kennedy's 1961 challenge to put men on the Moon before the end of the decade. Organizations involved in early research include NACA, the Flight Research Center (now Dryden) Bell Aircraft Corporation. The discussion focuses on development of a flight simulator to model the Moon's reduced gravity and development of the Lunar Landing Research Vehicle.

  1. Mathematical Modeling of the Braking System of Wheeled Mainline Aircraft

    Directory of Open Access Journals (Sweden)

    I. S. Shumilov

    2016-01-01

    Full Text Available The braking system of the landing gear wheels of a mainline aircraft has to meet mandatory requirements laid out in the Aviation Regulations AP-25 (Para 25.735. «Brakes and brake systems". These requirements are essential when creating the landing gear wheel brake control system (WBCS and are used as main initial data in its mathematical modeling. The WBCS is one of the most important systems to ensure the safe completion of the flight. It is a complex of devices, i.e. units (hydraulic, electrical, and mechanical, connected through piping, wiring, mechanical constraints. This complex should allow optimizing the braking process when a large number of parameters change. The most important of them are the following: runway friction coefficient (RFC, lifting force, weight and of the aircraft, etc. The main structural elements involved in braking the aircraft are: aircraft wheels with pneumatics (air tires and brake discs, WBCS, and cooling system of gear wheels when braking.To consider the aircraft deceleration on the landing run is of essence at the stage of design, development, and improvement of brakes and braking systems. Based on analysis of equation of the aircraft motion and energy balance can be determined energy loading and its basic design parameters, braking distances and braking time.As practice and analysis of energy loading show, they (brake + wheel absorb the aircraftpossessed kinetic energy at the start of braking as much as 60-70%, 70-80%, and 80-90%, respectively, under normal increased, and emergency operating conditions. The paper presents a procedure for the rapid calculation of energy loading of the brake wheel.Currently, the mainline aircrafts use mainly electrohydraulic brake systems in which there are the main, backup, and emergency-parking brake systems. All channels are equipped with automatic anti-skid systems. Their presence in the emergency (the third reserve channel significantly improves the reliability and safety of

  2. Aircraft Fuel Systems Career Ladder.

    Science.gov (United States)

    1985-09-01

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

  3. A domain model for land administration

    NARCIS (Netherlands)

    Lemmen, C.H.J.

    2012-01-01

    75% or the “people to land relationships” worldwide are not documented. This concerns about 4.5 billion cases. With a growing population this situation results in land disputes, land grabbing and neglecting of rights of local people. Land Administration provides documentation on people to land relat

  4. System identification methods for aircraft flight control development and validation

    Science.gov (United States)

    Tischler, Mark B.

    1995-01-01

    System-identification methods compose a mathematical model, or series of models, from measurements of inputs and outputs of dynamic systems. The extracted models allow the characterization of the response of the overall aircraft or component subsystem behavior, such as actuators and on-board signal processing algorithms. This paper discusses the use of frequency-domain system-identification methods for the development and integration of aircraft flight-control systems. The extraction and analysis of models of varying complexity from nonparametric frequency-responses to transfer-functions and high-order state-space representations is illustrated using the Comprehensive Identification from FrEquency Responses (CIFER) system-identification facility. Results are presented for test data of numerous flight and simulation programs at the Ames Research Center including rotorcraft, fixed-wing aircraft, advanced short takeoff and vertical landing (ASTOVL), vertical/short takeoff and landing (V/STOL), tiltrotor aircraft, and rotor experiments in the wind tunnel. Excellent system characterization and dynamic response prediction is achieved for this wide class of systems. Examples illustrate the role of system-identification technology in providing an integrated flow of dynamic response data around the entire life-cycle of aircraft development from initial specifications, through simulation and bench testing, and into flight-test optimization.

  5. Lunar Reconnaissance Orbiter Camera Observations Relating to Science and Landing Site Selection in South Pole-Aitken Basin for a Robotic Sample Return Mission

    Science.gov (United States)

    Jolliff, B. L.; Clegg-Watkins, R. N.; Petro, N. E.; Lawrence, S. J.

    2016-12-01

    The Moon's South Pole-Aitken basin (SPA) is a high priority target for Solar System exploration, and sample return from SPA is a specific objective in NASA's New Frontiers program. Samples returned from SPA will improve our understanding of early lunar and Solar System events, mainly by placing firm timing constraints on SPA formation and post-SPA late-heavy bombardment (LHB). Lunar Reconnaissance Orbiter Camera (LROC) images and topographic data, especially Narrow Angle Camera (NAC) scale (1-3 mpp) morphology and digital terrain model (DTM) data are critical for selecting landing sites and assessing landing hazards. Rock components in regolith at a given landing site should include (1) original SPA impact-melt rocks and breccia (to determine the age of the impact event and what materials were incorporated into the melt); (2) impact-melt rocks and breccia from large craters and basins (other than SPA) that represent the post-SPA LHB interval; (3) volcanic basalts derived from the sub-SPA mantle; and (4) older, "cryptomare" (ancient buried volcanics excavated by impact craters, to determine the volcanic history of SPA basin). All of these rock types are sought for sample return. The ancient SPA-derived impact-melt rocks and later-formed melt rocks are needed to determine chronology, and thus address questions of early Solar System dynamics, lunar history, and effects of giant impacts. Surface compositions from remote sensing are consistent with mixtures of SPA impactite and volcanic materials, and near infrared spectral data distinguish areas with variable volcanic contents vs. excavated SPA substrate. Estimating proportions of these rock types in the regolith requires knowledge of the surface deposits, evaluated via morphology, slopes, and terrain ruggedness. These data allow determination of mare-cryptomare-nonmare deposit interfaces in combination with compositional and mineralogical remote sensing to establish the types and relative proportions of materials

  6. 49 CFR 173.172 - Aircraft hydraulic power unit fuel tank.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Aircraft hydraulic power unit fuel tank. 173.172 Section 173.172 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... Class 1 and Class 7 § 173.172 Aircraft hydraulic power unit fuel tank. Aircraft hydraulic power...

  7. Indoor air quality investigation on commercial aircraft.

    Science.gov (United States)

    Lee, S C; Poon, C S; Li, X D; Luk, F

    1999-09-01

    Sixteen flights had been investigated for indoor air quality (IAQ) on Cathay Pacific aircraft from June 1996 to August 1997. In general, the air quality on Cathay Pacific aircraft was within relevant air quality standards because the average age of aircraft was less than 2 years. Carbon dioxide (CO2) levels on all flights measured were below the Federal Aviation Administration (FAA) standard (30,000 ppm). The CO2 level was substantially higher during boarding and de-boarding than cruise due to low fresh air supply. Humidity on the aircraft was low, especially for long-haul flights. Minimum humidity during cruise was below the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) minimum humidity standard (20%). The average temperature was within a comfortable temperature range of 23 +/- 2 degrees C. The vertical temperature profile on aircraft was uniform and below the International Standard Organization (ISO) standard. Carbon monoxide levels were below the FAA standard (50 ppm). Trace amount of ozone detected ranged from undetectable to 90 ppb, which was below the FAA standard. Particulate level was low for most non-smoking flights, but peaks were observed during boarding and de-boarding. The average particulate level in smoking flights (138 micrograms/m3) was higher than non-smoking flights (7.6 micrograms/m3). The impact on IAQ by switching from low-mode to high-mode ventilation showed a reduction in CO2 levels, temperature, and relative humidity.

  8. Photogrammetry, Digital mapping and Land Informations Systems

    DEFF Research Database (Denmark)

    Frederiksen, Poul

    1998-01-01

    Monitoring activities on photogrammetry, digital mapping and land information systems in State Land Service in Latvia in relation to the EU Phare Project Phase II, Technical Assistance to land Privatisation and registration in Latvia.......Monitoring activities on photogrammetry, digital mapping and land information systems in State Land Service in Latvia in relation to the EU Phare Project Phase II, Technical Assistance to land Privatisation and registration in Latvia....

  9. Characterization and Feasibility Assessment of Recycled Paper Mill Sludges for Land Application in Relation to the Environment

    Directory of Open Access Journals (Sweden)

    Rosazlin Abdullah

    2015-08-01

    Full Text Available The disposal of industrial paper mill sludge waste is a big issue and has a great importance all over the world. A study was conducted to determine the chemical properties of recycled paper mill sludge (RPMS and assess its possibilities for land application. RPMS samples were collected from six different paper mills in Malaysia and analyzed for physical and chemical properties, heavy metals, polycyclic aromatic hydrocarbons, 13C-NMR spectra and for the presence of dioxins/furans. The RPMS was dewatered, sticky with a strong odour, an average moisture of 65.08%, pH 7.09, cation exchange capacity (CEC 14.43 cmol (+ kg–1, N 1.45, P 0.18, K 0.12, Ca 0.82, Mg 0.73, Na 0.76 and Al, 1.38%. The polycyclic aromatic hydrocarbons (PAHs and heavy metals levels were below the standard Class 2 limits. The dioxin and furan were in below the standard concentration of Class 1. The most prominent peak in the 13C-NMR spectra of RPMS was centered at 31 ppm, proving the presence of methylene (-CH2 groups in long aliphatic chains, with lipids and proteins. The signal at 89 ppm and highly shielded shoulder at 83 ppm were due to presence of cellulose carbon C-4, and the peak at 63 and 65 ppm was due to the cellulose carbon spectrum. The RPMS therefore contains significant amount of nutrients with safe levels of heavy metals and PAHs for environment and can be used as a fertilizer and soil amendment for land application.

  10. Characterization and Feasibility Assessment of Recycled Paper Mill Sludges for Land Application in Relation to the Environment.

    Science.gov (United States)

    Abdullah, Rosazlin; Ishak, Che Fauziah; Kadir, Wan Rasidah; Bakar, Rosenani Abu

    2015-08-01

    The disposal of industrial paper mill sludge waste is a big issue and has a great importance all over the world. A study was conducted to determine the chemical properties of recycled paper mill sludge (RPMS) and assess its possibilities for land application. RPMS samples were collected from six different paper mills in Malaysia and analyzed for physical and chemical properties, heavy metals, polycyclic aromatic hydrocarbons, (13)C-NMR spectra and for the presence of dioxins/furans. The RPMS was dewatered, sticky with a strong odour, an average moisture of 65.08%, pH 7.09, cation exchange capacity (CEC) 14.43 cmol (+) kg(-1), N 1.45, P 0.18, K 0.12, Ca 0.82, Mg 0.73, Na 0.76 and Al, 1.38%. The polycyclic aromatic hydrocarbons (PAHs) and heavy metals levels were below the standard Class 2 limits. The dioxin and furan were in below the standard concentration of Class 1. The most prominent peak in the (13)C-NMR spectra of RPMS was centered at 31 ppm, proving the presence of methylene (-CH2) groups in long aliphatic chains, with lipids and proteins. The signal at 89 ppm and highly shielded shoulder at 83 ppm were due to presence of cellulose carbon C-4, and the peak at 63 and 65 ppm was due to the cellulose carbon spectrum. The RPMS therefore contains significant amount of nutrients with safe levels of heavy metals and PAHs for environment and can be used as a fertilizer and soil amendment for land application.

  11. Characterization and Feasibility Assessment of Recycled Paper Mill Sludges for Land Application in Relation to the Environment

    Science.gov (United States)

    Abdullah, Rosazlin; Ishak, Che Fauziah; Kadir, Wan Rasidah; Bakar, Rosenani Abu

    2015-01-01

    The disposal of industrial paper mill sludge waste is a big issue and has a great importance all over the world. A study was conducted to determine the chemical properties of recycled paper mill sludge (RPMS) and assess its possibilities for land application. RPMS samples were collected from six different paper mills in Malaysia and analyzed for physical and chemical properties, heavy metals, polycyclic aromatic hydrocarbons, 13C-NMR spectra and for the presence of dioxins/furans. The RPMS was dewatered, sticky with a strong odour, an average moisture of 65.08%, pH 7.09, cation exchange capacity (CEC) 14.43 cmol (+) kg–1, N 1.45, P 0.18, K 0.12, Ca 0.82, Mg 0.73, Na 0.76 and Al, 1.38%. The polycyclic aromatic hydrocarbons (PAHs) and heavy metals levels were below the standard Class 2 limits. The dioxin and furan were in below the standard concentration of Class 1. The most prominent peak in the 13C-NMR spectra of RPMS was centered at 31 ppm, proving the presence of methylene (-CH2) groups in long aliphatic chains, with lipids and proteins. The signal at 89 ppm and highly shielded shoulder at 83 ppm were due to presence of cellulose carbon C-4, and the peak at 63 and 65 ppm was due to the cellulose carbon spectrum. The RPMS therefore contains significant amount of nutrients with safe levels of heavy metals and PAHs for environment and can be used as a fertilizer and soil amendment for land application. PMID:26262636

  12. High-Speed Propeller for Aircraft

    Science.gov (United States)

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

    1986-01-01

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

  13. Gambia Land Use Land Cover

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This series of three-period land use land cover (LULC) datasets (1975, 2000, and 2013) aids in monitoring change in West Africa’s land resources (exception is...

  14. Aircraft Emissions Characterization

    Science.gov (United States)

    1988-03-01

    sample from each trap through a heated (1500C) six-port valve ’ Carle Instruments Model 5621) and onto the analytical column. The coLoponents in each...Environmental Protection, Vol. II. Aircraft Engine Emissions, Int. Civil Aviation Organ., 1981. 7. Nebel , G. J., "Benzene in Auto Exhaust," J. Air Poll

  15. Robots for Aircraft Maintenance

    Science.gov (United States)

    1993-01-01

    Marshall Space Flight Center charged USBI (now Pratt & Whitney) with the task of developing an advanced stripping system based on hydroblasting to strip paint and thermal protection material from Space Shuttle solid rocket boosters. A robot, mounted on a transportable platform, controls the waterjet angle, water pressure and flow rate. This technology, now known as ARMS, has found commercial applications in the removal of coatings from jet engine components. The system is significantly faster than manual procedures and uses only minimal labor. Because the amount of "substrate" lost is minimal, the life of the component is extended. The need for toxic chemicals is reduced, as is waste disposal and human protection equipment. Users of the ARMS work cell include Delta Air Lines and the Air Force, which later contracted with USBI for development of a Large Aircraft Paint Stripping system (LARPS). LARPS' advantages are similar to ARMS, and it has enormous potential in military and civil aircraft maintenance. The technology may also be adapted to aircraft painting, aircraft inspection techniques and paint stripping of large objects like ships and railcars.

  16. Aircraft noise prediction

    Science.gov (United States)

    Filippone, Antonio

    2014-07-01

    This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper addresses items for further research and development. Examples are shown for several airplanes, including the Airbus A319-100 (CFM engines), the Bombardier Dash8-Q400 (PW150 engines, Dowty R408 propellers) and the Boeing B737-800 (CFM engines). Predictions are done with the flight mechanics code FLIGHT. The transfer function between flight mechanics and the noise prediction is discussed in some details, along with the numerical procedures for validation and verification. Some code-to-code comparisons are shown. It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity. In particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

  17. Aircraft Oxygen Generation

    Science.gov (United States)

    2012-02-01

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

  18. Occurrence of selected trace elements and organic compounds and their relation to land use in the Willamette River basin, Oregon, 1992-94

    Science.gov (United States)

    Anderson, C.W.; Rinella, F.A.; Rounds, S.A.

    1996-01-01

    Between 1992 and 1994, the U.S.Geological Survey conducted a study of trace elements and organic compounds in the Willamette River Basin, Oregon, as part of the Willamette River Basin Water Quality Study. Low-level analyses were performed for trace elements, volatile organic compounds, organochlorine compounds, and pesticides. Overall, 94 water samples were collected from 40 sites, during predominantly high-flow conditions, representing urban, agricultural, mixed, and forested land uses. Although most observed concentrations were relatively low, some exceedances of water-quality criteria for acute and chronic toxicity and for the protection of human health were observed.

  19. Transport jet aircraft noise abatement in foreign countries: Growth, structure, impact. Volume 2: Pacific Basin, August 1980. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, F.A.

    1980-08-01

    Noise control measures at the international airports of Hawaii, New Zealand, Australia, Hong Kong, Japan, and Singapore were studied. Factors in noise control, such as government structure are examined. The increasing power of environmental agencies vis-a-vis aviation departments is noted. The following methods of dealing with aircraft noise are examined by type of control: noise at the source control noise emmission controls, zoning, building codes, subsidies for relocation, insulation, loss in property values, and for TV, radio and telephone interference and noise-related landing charges.

  20. Multi-spectrum-based enhanced synthetic vision system for aircraft DVE operations

    Science.gov (United States)

    Kashyap, Sudesh K.; Naidu, V. P. S.; Shanthakumar, N.

    2016-04-01

    This paper focus on R&D being carried out at CSIR-NAL on Enhanced Synthetic Vision System (ESVS) for Indian regional transport aircraft to enhance all weather operational capabilities with safety and pilot Situation Awareness (SA) improvements. Flight simulator has been developed to study ESVS related technologies and to develop ESVS operational concepts for all weather approach and landing and to provide quantitative and qualitative information that could be used to develop criteria for all-weather approach and landing at regional airports in India. Enhanced Vision System (EVS) hardware prototype with long wave Infrared sensor and low light CMOS camera is used to carry out few field trials on ground vehicle at airport runway at different visibility conditions. Data acquisition and playback system has been developed to capture EVS sensor data (image) in time synch with test vehicle inertial navigation data during EVS field experiments and to playback the experimental data on ESVS flight simulator for ESVS research and concept studies. Efforts are on to conduct EVS flight experiments on CSIR-NAL research aircraft HANSA in Degraded Visual Environment (DVE).

  1. Nonlinear dynamics of a vectored thrust aircraft

    DEFF Research Database (Denmark)

    Sørensen, C.B; Mosekilde, Erik

    1996-01-01

    With realistic relations for the aerodynamic coefficients, numerical simulations are applied to study the longitudional dynamics of a thrust vectored aircraft. As function of the thrust magnitude and the thrust vectoring angle the equilibrium state exhibits two saddle-node bifurcations and three...

  2. Lectures on Composite Materials for Aircraft Structures,

    Science.gov (United States)

    1982-10-01

    lectures are related to structural applications of composites . In Lecture 7, the basic theory that is needed for composite structural analysis is...which composites have been taken up for aeronautical applications. Several specific applications of composites in aircraft structures am described in

  3. Nonlinear dynamics of a vectored thrust aircraft

    DEFF Research Database (Denmark)

    Sørensen, C.B; Mosekilde, Erik

    1996-01-01

    With realistic relations for the aerodynamic coefficients, numerical simulations are applied to study the longitudional dynamics of a thrust vectored aircraft. As function of the thrust magnitude and the thrust vectoring angle the equilibrium state exhibits two saddle-node bifurcations and three ...

  4. Control optimization, stabilization and computer algorithms for aircraft applications

    Science.gov (United States)

    Athans, M. (Editor); Willsky, A. S. (Editor)

    1982-01-01

    The analysis and design of complex multivariable reliable control systems are considered. High performance and fault tolerant aircraft systems are the objectives. A preliminary feasibility study of the design of a lateral control system for a VTOL aircraft that is to land on a DD963 class destroyer under high sea state conditions is provided. Progress in the following areas is summarized: (1) VTOL control system design studies; (2) robust multivariable control system synthesis; (3) adaptive control systems; (4) failure detection algorithms; and (5) fault tolerant optimal control theory.

  5. Aircraft automatic flight control system with model inversion

    Science.gov (United States)

    Smith, G. A.; Meyer, George

    1990-01-01

    A simulator study was conducted to verify the advantages of a Newton-Raphson model-inversion technique as a design basis for an automatic trajectory control system in an aircraft with highly nonlinear characteristics. The simulation employed a detailed mathematical model of the aerodynamic and propulsion system performance characteristics of a vertical-attitude takeoff and landing tactical aircraft. The results obtained confirm satisfactory control system performance over a large portion of the flight envelope. System response to wind gusts was satisfactory for various plausible combinations of wind magnitude and direction.

  6. Aircraft automatic flight control system with model inversion

    Science.gov (United States)

    Smith, G. A.; Meyer, George

    1990-01-01

    A simulator study was conducted to verify the advantages of a Newton-Raphson model-inversion technique as a design basis for an automatic trajectory control system in an aircraft with highly nonlinear characteristics. The simulation employed a detailed mathematical model of the aerodynamic and propulsion system performance characteristics of a vertical-attitude takeoff and landing tactical aircraft. The results obtained confirm satisfactory control system performance over a large portion of the flight envelope. System response to wind gusts was satisfactory for various plausible combinations of wind magnitude and direction.

  7. Bioelectric Control of a 757 Class High Fidelity Aircraft Simulation

    Science.gov (United States)

    Jorgensen, Charles; Wheeler, Kevin; Stepniewski, Slawomir; Norvig, Peter (Technical Monitor)

    2000-01-01

    This paper presents results of a recent experiment in fine grain Electromyographic (EMG) signal recognition, We demonstrate bioelectric flight control of 757 class simulation aircraft landing at San Francisco International Airport. The physical instrumentality of a pilot control stick is not used. A pilot closes a fist in empty air and performs control movements which are captured by a dry electrode array on the arm, analyzed and routed through a flight director permitting full pilot outer loop control of the simulation. A Vision Dome immersive display is used to create a VR world for the aircraft body mechanics and flight changes to pilot movements. Inner loop surfaces and differential aircraft thrust is controlled using a hybrid neural network architecture that combines a damage adaptive controller (Jorgensen 1998, Totah 1998) with a propulsion only based control system (Bull & Kaneshige 1997). Thus the 757 aircraft is not only being flown bioelectrically at the pilot level but also demonstrates damage adaptive neural network control permitting adaptation to severe changes in the physical flight characteristics of the aircraft at the inner loop level. To compensate for accident scenarios, the aircraft uses remaining control surface authority and differential thrust from the engines. To the best of our knowledge this is the first time real time bioelectric fine-grained control, differential thrust based control, and neural network damage adaptive control have been integrated into a single flight demonstration. The paper describes the EMG pattern recognition system and the bioelectric pattern recognition methodology.

  8. Simulating feedbacks in land use and land cover change models

    NARCIS (Netherlands)

    Verburg, P.H.

    2006-01-01

    In spite of the many advances in land use and land cover change modelling over the past decade many challenges remain. One of these challenges relates to the explicit treatment of feedback mechanisms in descriptive models of the land use system. This paper argues for model-based analysis to explore

  9. Aircraft noise and its nearfield propagation computations

    Institute of Scientific and Technical Information of China (English)

    Xin Zhang

    2012-01-01

    Noise generated by civil transport aircraft during take-off and approach-to-land phases of operation is an environmental problem.The aircraft noise problem is firstly reviewed in this article.The review is followed by a description and assessment of a number of sound propagation methods suitable for applications with a background mean flow field pertinent to aircraft noise.Of the three main areas of the noise problem,i.e.generation,propagation,and radiation,propagation provides a vital link between near-field noise generation and far-field radiation.Its accurate assessment ensures the overall validity of a prediction model.Of the various classes of propagation equations,linearised Euler equations are often casted in either time domain or frequency domain.The equations are often solved numerically by computational aeroacoustics techniques,bur are subject to the onset of Kelvin-Helmholtz (K-H) instability modes which may ruin the solutions. Other forms of linearised equations,e.g.acoustic perturbation equations have been proposed,with differing degrees of success.

  10. Inventories and mobilization of unsaturated zone sulfate, fluoride, and chloride related to land use change in semiarid regions, southwestern United States and Australia

    Science.gov (United States)

    Scanlon, B.R.; Stonestrom, D.A.; Reedy, R.C.; Leaney, F.W.; Gates, J.; Cresswell, R.G.

    2009-01-01

    Unsaturated zone salt reservoirs are potentially mobilized by increased groundwater recharge as semiarid lands are cultivated. This study explores the amounts of pore water sulfate and fluoride relative to chloride in unsaturated zone profiles, evaluates their sources, estimates mobilization due to past land use change, and assesses the impacts on groundwater quality. Inventories of water-extractable chloride, sulfate, and fluoride were determined from borehole samples of soils and sediments collected beneath natural ecosystems (N = 4), nonirrigated ("rain-fed") croplands (N = 18), and irrigated croplands (N = 6) in the southwestern United States and in the Murray Basin, Australia. Natural ecosystems contain generally large sulfate inventories (7800-120,000 kg/ha) and lower fluoride inventories (630-3900 kg/ha) relative to chloride inventories (6600-41,000 kg/ha). Order-of-magnitude higher chloride concentrations in precipitation and generally longer accumulation times result in much larger chloride inventories in the Murray Basin than in the southwestern United States. Atmospheric deposition during the current dry interglacial climatic regime accounts for most of the measured sulfate in both U.S. and Australian regions. Fluoride inventories are greater than can be accounted for by atmospheric deposition in most cases, suggesting that fluoride may accumulate across glacial/ interglacial climatic cycles. Chemical modeling indicates that fluorite controls fluoride mobility and suggests that water-extractable fluoride may include some fluoride from mineral dissolution. Increased groundwater drainage/recharge following land use change readily mobilized chloride. Sulfate displacement fronts matched or lagged chloride fronts by up to 4 m. In contrast, fluoride mobilization was minimal in all regions. Understanding linkages between salt inventories, increased recharge, and groundwater quality is important for quantifying impacts of anthropogenic activities on groundwater

  11. Mozambique - Urban Land Regularization

    Data.gov (United States)

    Millennium Challenge Corporation — This baseline survey was developed for the impact evaluation of activities related to 'improving land access in urban hotspot areas.' The site-specific interventions...

  12. THE WAY OF ORGANIZING THE FLOW OF AIRCRAFT BY INVERSE "TROMBONE" TYPE LOCATION OF THE USEFUL MANOEUVRING AREA

    Directory of Open Access Journals (Sweden)

    G. N. Lebedev

    2015-01-01

    Full Text Available The problem of solving important practical tasks of organizing the flow of arriving aircraft from different directions to the same navigation point is described. This allows us to form list for landing and determine their priority.

  13. 14 CFR 91.535 - Stowage of food, beverage, and passenger service equipment during aircraft movement on the...

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Stowage of food, beverage, and passenger... Airplanes and Fractional Ownership Program Aircraft § 91.535 Stowage of food, beverage, and passenger... an aircraft on the surface, take off, or land when any food, beverage, or tableware furnished by the...

  14. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Science.gov (United States)

    2010-07-01

    ..., and adjacent waters, NC; danger zones for naval aircraft operations. 334.410 Section 334.410 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE...; danger zones for naval aircraft operations. (a) Target areas—(1) North Landing River (Currituck...

  15. 27 CFR 28.43 - Evidence of exportation and lading for use on vessels and aircraft: beer.

    Science.gov (United States)

    2010-04-01

    ... and lading for use on vessels and aircraft: beer. 28.43 Section 28.43 Alcohol, Tobacco Products and... lading for use on vessels and aircraft: beer. (a) Exportation. The exportation of beer to a foreign... certificate issued by an official of the country or possession where the beer has actually landed; or (6)...

  16. 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.

  17. Bioturbosina: Producción de cultivos energéticos para la aviación comercial Jet Biofuel: Production of energy-related crops for commercial aircraft

    Directory of Open Access Journals (Sweden)

    Ibis Sepúlveda González

    2012-06-01

    contribute on greenhouse gas emissions effect decrease and to ensure economic fuel availability. In order to add to jet fuel an increasing mixture of biofuel, a plan was developed. In Mexico this plan was set under "Flight Plan Towards Sustainable Biofuels" agenda, convoked by ASA between June 2010 and March 2011. When compared to jet fuel, jet biofuel must reduce greenhouse gas emission in more than 50% during its life cycle. It is also expected that when time elapses, thanks to technology, jet biofuel cost will be cut down, while petroleum will rise due its scarcity (Herrera and Morgan, 2010; García, 2010. In this way, at global level these companies had established that for year 2015 it must add 1 % of j et biofuel to j et fuel, for 2017; 10%, for 2020; 15%, and so on up to 50% as minimum to replace source of aircraft fuel for year 2050. Mexico shares 2% of aircraft fuel sales at worldwide level. This means a starting 40 millions liters demand of jet biofuel for year 2015 and around 700 millions litters for year 2020. The body in charge of promoting worldwide aircraft biofuel (Roundtable For Sustainable Biofuels - RSB, headquartered in École Politechnique Federale from Lausanne established 12 principles to fulfill in order to be accepted as jet biofuel oils supplier. These are related to ecological sustainability and social equity. The conditions Mexico can offer to face this first real biofuels demand as well as their likely effects are analyzed in the agenda

  18. Mapping land water and energy balance relations through conditional sampling of remote sensing estimates of atmospheric forcing and surface states

    Science.gov (United States)

    Farhadi, Leila; Entekhabi, Dara; Salvucci, Guido

    2016-04-01

    In this study, we develop and apply a mapping estimation capability for key unknown parameters that link the surface water and energy balance equations. The method is applied to the Gourma region in West Africa. The accuracy of the estimation method at point scale was previously examined using flux tower data. In this study, the capability is scaled to be applicable with remotely sensed data products and hence allow mapping. Parameters of the system are estimated through a process that links atmospheric forcing (precipitation and incident radiation), surface states, and unknown parameters. Based on conditional averaging of land surface temperature and moisture states, respectively, a single objective function is posed that measures moisture and temperature-dependent errors solely in terms of observed forcings and surface states. This objective function is minimized with respect to parameters to identify evapotranspiration and drainage models and estimate water and energy balance flux components. The uncertainty of the estimated parameters (and associated statistical confidence limits) is obtained through the inverse of Hessian of the objective function, which is an approximation of the covariance matrix. This calibration-free method is applied to the mesoscale region of Gourma in West Africa using multiplatform remote sensing data. The retrievals are verified against tower-flux field site data and physiographic characteristics of the region. The focus is to find the functional form of the evaporative fraction dependence on soil moisture, a key closure function for surface and subsurface heat and moisture dynamics, using remote sensing data.

  19. Relative roles of land- and ocean-atmosphere interactions in Asian-Pacific thermal contrast variability at the precessional band

    Science.gov (United States)

    Wang, Yue; Jian, ZhiMin; Zhao, Ping; Xiao, Dong; Chen, JunMing

    2016-01-01

    In a 250-kyr transient simulation of the Community Earth System Model (CESM), we identified a precessional forced seesaw of the summer middle-upper tropospheric eddy temperature between Asia and the North Pacific as the paleo-APO (Asian-Pacific oscillation). The paleo-APO variability is out of phase with the precession parameter. Corresponding to a positive paleo-APO phase, both the subtropical anticyclonic circulation over the North Pacific and the East Asian summer monsoon (EASM) strengthen. Summer anomalous sea surface temperature shows a western cold-eastern warm pattern over the extratropical North Pacific and a zonal positive-negative-positive pattern over the tropical Pacific. The variations in the simulated paleo-APO and East Asian southerly wind at the precessional band agree well with the geological proxies at the Dongge, Sanbao, Linzhu, and Hulu caves in China, which also implies that these proxies may well reflect the variability in the southerly wind over East Asia. Sensitivity experiments further reveal that the reduced precession parameter may enhance the positive paleo-APO phase and the associated EASM because of the response of the land-atmosphere interactions to the precessional insolation changes. The effect of the ocean-atmosphere interactions on the paleo-APO is secondary. PMID:27381940

  20. Back-extrapolating a land use regression model for estimating past exposures to traffic-related air pollution.

    Science.gov (United States)

    Levy, Ilan; Levin, Noam; Yuval; Schwartz, Joel D; Kark, Jeremy D

    2015-03-17

    Land use regression (LUR) models rely on air pollutant measurements for their development, and are therefore limited to recent periods where such measurements are available. Here we propose an approach to overcome this gap and calculate LUR models several decades before measurements were available. We first developed a LUR model for NOx using annual averages of NOx at all available air quality monitoring sites in Israel between 1991 and 2011 with time as one of the independent variables. We then reconstructed historical spatial data (e.g., road network) from historical topographic maps to apply the model's prediction to each year from 1961 to 2011. The model's predictions were then validated against independent estimates about the national annual NOx emissions from on-road vehicles in a top-down approach. The model's cross validated R2 was 0.74, and the correlation between the model's annual averages and the national annual NOx emissions between 1965 and 2011 was 0.75. Information about the road network and population are persistent predictors in many LUR models. The use of available historical data about these predictors to resolve the spatial variability of air pollutants together with complementary national estimates on the change in pollution levels over time enable historical reconstruction of exposures.

  1. Distribution of dissolved pesticides and other water quality constituents in small streams, and their relation to land use, in the Willamette River Basin, Oregon, 1996

    Science.gov (United States)

    Anderson, Chauncey W.; Wood, Tamara M.; Morace, Jennifer L.

    1997-01-01

    Water quality samples were collected at sites in 16 randomly selected agricultural and 4 urban subbasins as part of Phase III of the Willamette River Basin Water Quality Study in Oregon during 1996. Ninety-five samples were collected and analyzed for suspended sediment, conventional constituents (temperature, dissolved oxygen, pH, specific conductance, nutrients, biochemical oxygen demand, and bacteria) and a suite of 86 dissolved pesticides. The data were collected to characterize the distribution of dissolved pesticide concentrations in small streams (drainage areas 2.6? 13 square miles) throughout the basin, to document exceedances of water quality standards and guidelines, and to identify the relative importance of several upstream land use categories (urban, agricultural, percent agricultural land, percent of land in grass seed crops, crop diversity) and seasonality in affecting these distributions. A total of 36 pesticides (29 herbicides and 7 insecticides) were detected basinwide. The five most frequently detected compounds were the herbicides atrazine (99% of samples), desethylatrazine (93%), simazine (85%), metolachlor (85%), and diuron (73%). Fifteen compounds were detected in 12?35% of samples, and 16 compounds were detected in 1?9% of samples. Water quality standards or criteria were exceeded more frequently for conventional constituents than for pesticides. State of Oregon water quality standards were exceeded at all but one site for the indicator bacteria E. coli, 3 sites for nitrate, 10 sites for water temperature, 4 sites for dissolved oxygen, and 1 site for pH. Pesticide concentrations, which were usually less than 1 part per billion, exceeded State of Oregon or U.S. Environmental Protection Agency aquatic life toxicity criteria only for chlorpyrifos, in three samples from one site; such criteria have been established for only two other detected pesticides. However, a large number of unusually high concentrations (1?90 parts per billion) were

  2. Bonded structure application for aircraft. Kokuki ni okeru secchaku gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, O. (Japan Airlines Co. Ltd., Tokyo (Japan))

    1991-01-05

    Adhesives play an important role in a technology of the aircraft structure for which lightness and strength are required. The paper explains the present situation of bonding technology employed for aircraft, the honeycomb structure, production of composite materials and the related problems. Advantages and purposes of employing adhesives as substitutes for fasteners like screws, rivets, etc. are as follows: decreases in stress concentration, weight reduction, smoothing of surfaces, improvement of acoustic fatigue by adhesives flexibility, prevention of gas-liquid leakage. Epoxide adhesives are mainly used for aircraft. Together with tear straps, which are metal-metal bonded to the rear fuselage plate of aircraft, and waffle doublers, an aluminium honeycomb sandwich structure, whose weight is 1/7 of an aluminium plate same in rigidity, is used in such parts of aircraft as spoilers, outer plates of flaps, etc. The problem of the bonded structure is detachment. Therefore, how to prevent, discover and repair it is most important. 3 figs.

  3. An improved source model for aircraft interior noise studies

    Science.gov (United States)

    Mahan, J. R.; Fuller, C. R.

    1985-01-01

    There is concern that advanced turboprop engines currently being developed may produce excessive aircraft cabin noise level. This concern has stimulated renewed interest in developing aircraft interior noise reduction methods that do not significnatly increase take off weight. An existing analytical model for noise transmission into aircraft cabins was utilized to investigate the behavior of an improved propeller source model for use in aircraft interior noise studies. The new source model, a virtually rotating dipole, is shown to adequately match measured fuselage sound pressure distributions, including the correct phase relationships, for published data. The virtually rotating dipole is used to study the sensitivity of synchrophasing effectiveness to the fuselage sound pressure trace velocity distribution. Results of calculations are presented which reveal the importance of correctly modeling the surface pressure phase relations in synchrophasing and other aircraft interior noise studies.

  4. Lunar Reconnaissance Orbiter Camera Observations Relating to Science and Landing Site Selection in South Pole-Aitken Basin for a Robotic Sample Return Mission

    Science.gov (United States)

    Jolliff, B. L.; Clegg-Watkins, R. N.; Petro, N. E.; Lawrence, S. L.

    2016-01-01

    The Moon's South Pole-Aitken basin (SPA) is a high priority target for Solar System exploration, and sample return from SPA is a specific objective in NASA's New Frontiers program. Samples returned from SPA will improve our understanding of early lunar and Solar System events, mainly by placing firm timing constraints on SPA formation and the post-SPA late-heavy bombardment (LHB). Lunar Reconnaissance Orbiter Camera (LROC) images and topographic data, especially Narrow Angle Camera (NAC) scale (1-3 mpp) morphology and digital terrain model (DTM) data are critical for selecting landing sites and assessing landing hazards. Rock components in regolith at a given landing site should include (1) original SPA impact-melt rocks and breccia (to determine the age of the impact event and what materials were incorporated into the melt); (2) impact-melt rocks and breccia from large craters and basins (other than SPA) that represent the post-SPA LHB interval; (3) volcanic basalts derived from the sub-SPA mantle; and (4) older, "cryptomare" (ancient buried volcanics excavated by impact craters, to determine the volcanic history of SPA basin). All of these rock types are sought for sample return. The ancient SPA-derived impact-melt rocks and later-formed melt rocks are needed to determine chronology, and thus address questions of early Solar System dynamics, lunar history, and effects of giant impacts. Surface compositions from remote sensing are consistent with mixtures of SPA impactite and volcanic materials, and near infrared spectral data distinguish areas with variable volcanic contents vs. excavated SPA substrate. Estimating proportions of these rock types in the regolith requires knowledge of the surface deposits, evaluated via morphology, slopes, and terrain ruggedness. These data allow determination of mare-cryptomare-nonmare deposit interfaces in combination with compositional and mineralogical remote sensing to establish the types and relative proportions of materials

  5. Project ADIOS: Aircraft Deployable Ice Observation System

    Science.gov (United States)

    Gudmundsson, G. H.

    2013-12-01

    Regions of the Antarctic that are of scientific interest are often too heavily crevassed to enable a plane to land, or permit safe access from a field camp. We have developed an alternative strategy for instrumenting these regions: a sensor that can be dropped from an overflying aircraft. Existing aircraft deployable sensors are not suitable for long term operations in areas where snow accumulates, as they are quickly buried. We have overcome this problem by shaping the sensor like an aerodynamic mast with fins and a small parachute. After being released from the aircraft, the sensor accelerates to 42m/s and stabilizes during a 10s descent. On impact with the snow surface the sensor package buries itself to a depth of 1m then uses the large surface area of the fins to stop it burying further. This leaves a 1.5m mast protruding high above the snow surface to ensure a long operating life. The high impact kinetic energy and robust fin braking mechanism ensure that the design works in both soft and hard snow. Over the past two years we have developed and tested our design with a series of aircraft and wind tunnel tests. Last season we used this deployment strategy to successfully install a network of 31 single band GPS sensors in regions where crevassing has previously prevented science operations: Pine Island Glacier, West Antarctica, and Scar Inlet, Antarctic Peninsula. This season we intend to expand on this network by deploying a further 25 single and dual band GPS sensors on Thwaites Glacier, West Antarctica.

  6. Prediction of anthropometric accommodation in aircraft cockpits

    Science.gov (United States)

    Zehner, Gregory Franklin

    Designing aircraft cockpits to accommodate the wide range of body sizes existing in the U.S. population has always been a difficult problem for Crewstation Engineers. The approach taken in the design of military aircraft has been to restrict the range of body sizes allowed into flight training, and then to develop standards and specifications to ensure that the majority of the pilots are accommodated. Accommodation in this instance is defined as the ability to: (1) Adequately see, reach, and actuate controls; (2) Have external visual fields so that the pilot can see to land, clear for other aircraft, and perform a wide variety of missions (ground support/attack or air to air combat); and (3) Finally, if problems arise, the pilot has to be able to escape safely. Each of these areas is directly affected by the body size of the pilot. Unfortunately, accommodation problems persist and may get worse. Currently the USAF is considering relaxing body size entrance requirements so that smaller and larger people could become pilots. This will make existing accommodation problems much worse. This dissertation describes a methodology for correcting this problem and demonstrates the method by predicting pilot fit and performance in the USAF T-38A aircraft based on anthropometric data. The methods described can be applied to a variety of design applications where fitting the human operator into a system is a major concern. A systematic approach is described which includes: defining the user population, setting functional requirements that operators must be able to perform, testing the ability of the user population to perform the functional requirements, and developing predictive equations for selecting future users of the system. Also described is a process for the development of new anthropometric design criteria and cockpit design methods that assure body size accommodation is improved in the future.

  7. Inhalation Toxicology. V. Evaluation of Relative Toxicity to Rats of Thermal Decomposition Products from Two Aircraft Seat Fire-Blocking Materials.

    Science.gov (United States)

    1985-11-01

    only. The relative toxicity of the combustion gases was measured by determining time-to-incapacitation (ti) in the laboratory rat , the same endpoint... the laboratory rat was the measured response used to compare the relative toxicity of the combustion gases produced from the two materials. Because of

  8. 民用航空器侵权责任主体的相对性及其突破%The Relativity of Civil Aircraft Tort Liability Subject and Its Breakthrough

    Institute of Scientific and Technical Information of China (English)

    王锡柱

    2015-01-01

    The tort liability of civil aircraft in Tort Liability Law belongs to the category of high risk liability. Whether or not the operator of a civil aircraft is at fault or not,he has to assume responsibility. However,besides the operator,whether or not the third party is at fault could be taken as the responsibility subject,and whether the victim can claim directly to such third party,are not specified in Tort Liability Law,which results in the relativity of subject of tort liability in civil aircraft. The relativity to some extent is beneficial to victims as balance between risks and benefits as well as an embodiment of the economic responsibility,but the relativity is not conducive to intactness of tort liability law system and could not protect the benefits of victims and operators perfectly. Given the balance of interests as well as the standard of making a clear distinction between right and wrong,it is necessary to break the relativity,taking the third party at fault as responsibility subject and to give the victim the right to claim directly to the third party.%我国《侵权责任法》中民用航空器侵权责任属于高度危险责任范畴,民用航空器经营人有无过错,均应承担责任。然而,对于经营人之外有过失的第三人能否作为责任主体,以及受害人能否向此类第三人直接求偿并未在该法中得到明确,进而造成了民用航空器侵权责任主体的相对性。这种相对性在一定程度上保护了受害者,是风险与收益平衡的选择以及经济责任的体现,但是这种相对性不利于侵权责任法体系的完整,对于受害人以及航空器经营人的保护并不周延。基于利益平衡以及明辨是非的标准有必要突破这种责任主体的相对性,将具有过失的第三人作为责任主体,并赋予受害人向第三人的直接请求权。

  9. Land Rights at Last!

    Directory of Open Access Journals (Sweden)

    Heidi Norman

    2009-10-01

    Full Text Available In 1978 the Wran Government announced an Inquiry to investigate a range of issues including Aboriginal land rights recognition, the causes of Aboriginal social and economic disadvantage, heritage protection and commonwealth and state relations. The Select Committee, chaired by state member Maurie Keane, in its ‘First Report’ that focused on land rights, not only fundamentally changed the way Government’s liaise and consult with Aboriginal people, the Committee unanimously endorsed far-reaching recommendations including the ability to recover land, compensation for cultural loss and three-tier community driven administrative structure. All of this was set in the context of Aboriginal rights to self-determination and fundamental attachment to land as a cultural relationship and historical reality. The movement for land rights was the culmination of many years of land justice activism, shifting policy at the Commonwealth level and wider international movements contesting colonial rule and racism. More specifically the land rights movement in NSW was galvanised in response to the previous Government’s renewed efforts to assimilate Aboriginal people and revoke reserve lands and the limited land rights recognition made possible through the Aboriginal Lands Trust (herein ‘the Trust’. This paper argues a more focused and pronounced campaign emerged in the mid 1970s whereby land rights ‘time had come’ as a result of Aboriginal political activism and the alliances formed with and among left social movements. This movement created the political climate for the Wran Government’s announcement of the Select Committee Inquiry in 1978.

  10. Ukraine Agricultural Land Market Formation Preconditions

    Directory of Open Access Journals (Sweden)

    Evgen Dankevych

    2017-01-01

    Full Text Available The theoretical land relations reforming principles were reviewed.Land relations in agriculture transformation process was studied. The land use features were detected and agricultural land use efficiency analysis was conducted.Ukraine land market formation research problems results have been shown. It was established that private land ownership institution ambiguous attitude, rent relations deformation, lack of the property rights ensure mechanism inhibit the land market development. Sociological research of Ukrainian Polesie region to determine the prerequisites for agricultural land marketformation preconditions has been conducted. 787 respondents from Zhytomyr, Rivne and Volyn regions were interviewed. Land shares owners age structure, their distribution by education level, their employment, land shares owners and agricultural enterprises executives to the agricultural land sale moratorium cancellation attitudes, land purchase financial resources, directions of Ukrainian Polissya region land shares use, shares owners land issues level of awareness have been determined during the research. Was substantiated that agricultural land market turnover includes not only land sale moratorium cancellation but also the adoption of the legislative framework and the appropriate infrastructure development, one of the key elements of which is land relations regulation specialized state agency – State Land Bank.

  11. How does postural stability following a single leg drop jump landing task relate to postural stability during a single leg stance balance task?

    Science.gov (United States)

    Fransz, Duncan P; Huurnink, Arnold; Kingma, Idsart; van Dieën, Jaap H

    2014-09-22

    We aimed to verify whether the static phase after a single leg drop jump (DJ) landing on a force plate may serve as a proxy for a single leg stance (SLS) balance task, as this would increase the application possibilities of landing tasks in the evaluation of sensorimotor function in relation to injury rehabilitation or performance assessment. Twenty-five healthy participants performed two sessions of five valid trials for both tasks in a reproducibility-agreement design. Three postural stability outcome measures ('COP speed', 'COP sway' and 'Horizontal GRF') were calculated for DJ (5-20s after landing) and for SLS (15s), and were averaged per session. Paired T-tests revealed a learning effect of SLS for postural stability (4.6-6.1%; P-values 0.27). Only session 2 resulted in superior postural stability for SLS compared to DJ for 'COP speed' (5.0%; P=0.017) and 'Horizontal GRF' (8.2%; P=0.001). Bland and Altman methods demonstrated inter-session SD's of difference for DJ of 11-12% and for SLS of 10-12%, while inter-task SD's of difference ranged 10-17%. Precision ('SD within') was better for SLS concerning 'COP speed' (14-15% vs 13%) and 'Horizontal GRF' (18-20% vs 14-15%). In conclusion, postural stability during DJ and SLS cannot be considered interchangeable, due to a learning effect for SLS and inferior precision for DJ. However, a DJ task may be used as a proxy for static postural stability, although more than three trials are needed to achieve individual errors similar to SLS for 'COP speed' (4) and 'Horizontal GRF' (5).

  12. Aircraft Data Acquisition

    OpenAIRE

    Elena BALMUS

    2016-01-01

    The introduction of digital systems instead of analog ones has created a major separation in the aviation technology. Although the digital equipment made possible that the increasingly faster controllers take over, we should say that the real world remains essentially analogue [4]. Fly-by-wire designers attempting to control and measure the real feedback of an aircraft were forced to find a way to connect the analogue environment to their digital equipment. In order to manage the implications...

  13. Airline and Aircraft Reliability

    OpenAIRE

    Hauka, Maris; Paramonovs, Jurijs

    2014-01-01

    Development of the inspection programme of fatigue-prone aircraft construction under limitation of airline fatigue failure rate. The highest economical effectiveness of airline under limitation of fatigue failure rate and failure probability is discussed. For computing is used exponential regression, Monte Carlo method, Log Normal distribution, Markov chains and semi-Markov process theory. The minimax approach is offered for processing the results of full-scale fatigue approval test of an air...

  14. Slotted Aircraft Wing

    Science.gov (United States)

    McLean, James D. (Inventor); Witkowski, David P. (Inventor); Campbell, Richard L. (Inventor)

    2006-01-01

    A swept aircraft wing includes a leading airfoil element and a trailing airfoil element. At least one full-span slot is defined by the wing during at least one transonic condition of the wing. The full-span slot allows a portion of the air flowing along the lower surface of the leading airfoil element to split and flow over the upper surface of the trailing airfoil element so as to achieve a performance improvement in the transonic condition.

  15. Stratospheric aircraft: Impact on the stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, H.

    1992-02-01

    The steady-state distribution of natural stratospheric ozone is primarily maintained through production by ultraviolet photolysis of molecular oxygen, destruction by a catalytic cycle involving nitrogen oxides (NO{sub x}), and relocation by air motions within the stratosphere. Nitrogen oxides from the exhausts of a commercially viable fleet of supersonic transports would exceed the natural source of stratospheric nitrogen oxides if the t should be equipped with 1990 technology jet engines. This model-free comparison between a vital natural global ingredient and a proposed new industrial product shows that building a large fleet of passenger stratospheric aircraft poses a significant global problem. NASA and aircraft industries have recognized this problem and are studying the redesign of jet aircraft engines in order to reduce the nitrogen oxides emissions. In 1989 atmospheric models identified two other paths by which the ozone destroying effects of stratospheric aircraft might be reduced or eliminated: (1) Use relatively low supersonic Mach numbers and flight altitudes. For a given rate of nitrogen oxides injection into the stratosphere, the calculated reduction of total ozone is a strong function of altitude, and flight altitudes well below 20 kilometers give relatively low calculated ozone reductions. (2) Include heterogeneous chemistry in the two-dimensional model calculations. Necessary conditions for answering the question on the title above are to improve the quality of our understanding of the lower stratosphere and to broaden our knowledge of hetergeneous stratospheric chemistry. This article reviews recently proposed new mechanisms for heterogeneous reactions on the global stratospheric sulfate aerosols.

  16. Stratospheric aircraft: Impact on the stratosphere?

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, H.

    1992-02-01

    The steady-state distribution of natural stratospheric ozone is primarily maintained through production by ultraviolet photolysis of molecular oxygen, destruction by a catalytic cycle involving nitrogen oxides (NO{sub x}), and relocation by air motions within the stratosphere. Nitrogen oxides from the exhausts of a commercially viable fleet of supersonic transports would exceed the natural source of stratospheric nitrogen oxides if the t should be equipped with 1990 technology jet engines. This model-free comparison between a vital natural global ingredient and a proposed new industrial product shows that building a large fleet of passenger stratospheric aircraft poses a significant global problem. NASA and aircraft industries have recognized this problem and are studying the redesign of jet aircraft engines in order to reduce the nitrogen oxides emissions. In 1989 atmospheric models identified two other paths by which the ozone destroying effects of stratospheric aircraft might be reduced or eliminated: (1) Use relatively low supersonic Mach numbers and flight altitudes. For a given rate of nitrogen oxides injection into the stratosphere, the calculated reduction of total ozone is a strong function of altitude, and flight altitudes well below 20 kilometers give relatively low calculated ozone reductions. (2) Include heterogeneous chemistry in the two-dimensional model calculations. Necessary conditions for answering the question on the title above are to improve the quality of our understanding of the lower stratosphere and to broaden our knowledge of hetergeneous stratospheric chemistry. This article reviews recently proposed new mechanisms for heterogeneous reactions on the global stratospheric sulfate aerosols.

  17. Ground-water quality and its relation to hydrogeology, land use, and surface-water quality in the Red Clay Creek basin, Piedmont Physiographic Province, Pennsylvania and Delaware

    Science.gov (United States)

    Senior, Lisa A.

    1996-01-01

    The Red Clay Creek Basin in the Piedmont Physiographic Province of Pennsylvania and Delaware is a 54-square-mile area underlain by a structurally complex assemblage of fractured metamorphosed sedimentary and igneous rocks that form a water-table aquifer. Ground-water-flow systems generally are local, and ground water discharges to streams. Both ground water and surface water in the basin are used for drinking-water supply. Ground-water quality and the relation between ground-water quality and hydrogeologic and land-use factors were assessed in 1993 in bedrock aquifers of the basin. A total of 82 wells were sampled from July to November 1993 using a stratified random sampling scheme that included 8 hydrogeologic and 4 land-use categories to distribute the samples evenly over the area of the basin. The eight hydrogeologic units were determined by formation or lithology. The land-use categories were (1) forested, open, and undeveloped; (2) agricultural; (3) residential; and (4) industrial and commercial. Well-water samples were analyzed for major and minor ions, nutrients, volatile organic compounds (VOC's), pesticides, polychlorinated biphenyl compounds (PCB's), and radon-222. Concentrations of some constituents exceeded maximum contaminant levels (MCL) or secondary maximum contaminant levels (SMCL) established by the U.S. Environmental Protection Agency for drinking water. Concentrations of nitrate were greater than the MCL of 10 mg/L (milligrams per liter) as nitrogen (N) in water from 11 (13 percent) of 82 wells sampled; the maximum concentration was 38 mg/L as N. Water from only 1 of 82 wells sampled contained VOC's or pesticides that exceeded a MCL; water from that well contained 3 mg/L chlordane and 1 mg/L of PCB's. Constituents or properties of well-water samples that exceeded SMCL's included iron, manganese, dissolved solids, pH, and corrosivity. Water from 70 (85 percent) of the 82 wells sampled contained radon-222 activities greater than the proposed MCL of

  18. Ground-water quality and its relation to hydrogeology, land use, and surface-water quality in the Red Clay Creek basin, Piedmont Physiographic Province, Pennsylvania and Delaware

    Science.gov (United States)

    Senior, Lisa A.

    1996-01-01

    The Red Clay Creek Basin in the Piedmont Physiographic Province of Pennsylvania and Delaware is a 54-square-mile area underlain by a structurally complex assemblage of fractured metamorphosed sedimentary and igneous rocks that form a water-table aquifer. Ground-water-flow systems generally are local, and ground water discharges to streams. Both ground water and surface water in the basin are used for drinking-water supply. Ground-water quality and the relation between ground-water quality and hydrogeologic and land-use factors were assessed in 1993 in bedrock aquifers of the basin. A total of 82 wells were sampled from July to November 1993 using a stratified random sampling scheme that included 8 hydrogeologic and 4 land-use categories to distribute the samples evenly over the area of the basin. The eight hydrogeologic units were determined by formation or lithology. The land-use categories were (1) forested, open, and undeveloped; (2) agricultural; (3) residential; and (4) industrial and commercial. Well-water samples were analyzed for major and minor ions, nutrients, volatile organic compounds (VOC's), pesticides, polychlorinated biphenyl compounds (PCB's), and radon-222. Concentrations of some constituents exceeded maximum contaminant levels (MCL) or secondary maximum contaminant levels (SMCL) established by the U.S. Environmental Protection Agency for drinking water. Concentrations of nitrate were greater than the MCL of 10 mg/L (milligrams per liter) as nitrogen (N) in water from 11 (13 percent) of 82 wells sampled; the maximum concentration was 38 mg/L as N. Water from only 1 of 82 wells sampled contained VOC's or pesticides that exceeded a MCL; water from that well contained 3 mg/L chlordane and 1 mg/L of PCB's. Constituents or properties of well-water samples that exceeded SMCL's included iron, manganese, dissolved solids, pH, and corrosivity. Water from 70 (85 percent) of the 82 wells sampled contained radon-222 activities greater than the proposed MCL of

  19. Pollutant monitoring of aircraft exhaust with multispectral imaging

    Science.gov (United States)

    Berkson, Emily E.; Messinger, David W.

    2016-10-01

    Communities surrounding local airports are becoming increasingly concerned about the aircraft pollutants emitted during the landing-takeoff (LTO) cycle, and their potential for negative health effects. Chicago, Los Angeles, Boston and London have all recently been featured in the news regarding concerns over the amount of airport pollution being emitted on a daily basis, and several studies have been published on the increased risks of cancer for those living near airports. There are currently no inexpensive, portable, and unobtrusive sensors that can monitor the spatial and temporal nature of jet engine exhaust plumes. In this work we seek to design a multispectral imaging system that is capable of tracking exhaust plumes during the engine idle phase, with a specific focus on unburned hydrocarbon (UHC) emissions. UHCs are especially potent to local air quality, and their strong absorption features allow them to act as a spatial and temporal plume tracer. Using a Gaussian plume to radiometrically model jet engine exhaust, we have begun designing an inexpensive, portable, and unobtrusive imaging system to monitor the relative amount of pollutants emitted by aircraft in the idle phase. The LWIR system will use two broadband filters to detect emitted UHCs. This paper presents the spatial and temporal radiometric models of the exhaust plume from a typical jet engine used on 737s. We also select filters for plume tracking, and propose an imaging system layout for optimal detectibility. In terms of feasibility, a multispectral imaging system will be two orders of magnitude cheaper than current unobtrusive methods (PTR-MS) used to monitor jet engine emissions. Large-scale impacts of this work will include increased capabilities to monitor local airport pollution, and the potential for better-informed decision-making regarding future developments to airports.

  20. Fire history, related to climate and land use in three southern Appalachian landscapes in the eastern United States.

    Science.gov (United States)

    Flatley, William T; Lafon, Charles W; Grissino-Mayer, Henri D; LaForest, Lisa B

    2013-09-01

    Fire-maintained ecosystems and associated species are becoming increasingly rare in the southern Appalachian Mountains because of fire suppression policies implemented in the early 20th century. Restoration of these communities through prescribed fire has been hindered by a lack of information on historical fire regimes. To characterize past fire regimes, we collected and absolutely dated the tree rings on cross sections from 242 fire-scarred trees at three different sites in the southern Appalachian Mountains of Tennessee and North Carolina. Our objectives were to (1) characterize the historical frequency of fire in southern Appalachian mixed pine-oak forests, (2) assess the impact of interannual climatic variability on the historical occurrence of fire, and (3) determine whether changes in human culture and land use altered the frequency of fire. Results demonstrate that fires burned frequently at all three sites for at least two centuries prior to the implementation of fire suppression and prevention in the early to mid 20th century. Composite mean fire return intervals were 2-4 yr, and point mean fire return intervals were 9-13 yr. Area-wide fires that burned across multiple stands occurred at 6-13-yr intervals. The majority of fires were recorded during the dormant season. Fire occurrence exhibited little relationship with reconstructed annual drought conditions. Also, fire activity did not change markedly during the transition from Native American to Euro-American settlement or during the period of industrial logging at the start of the 20th century. Fire activity declined significantly, however, during the fire suppression period, with a nearly complete absence of fire during recent decades. The characterization of past fire regimes should provide managers with specific targets for restoration of fire-associated communities in the southern Appalachian Mountains. The fire chronologies reported here are among the longest tree-ring reconstructions of fire

  1. Temporal and spatial changes in land use patterns and biodiversity in relation to farm productivity at multiple scales in Tigray, Ethiopia

    NARCIS (Netherlands)

    Hadgu Meles, K.

    2008-01-01

    Loss of biodiversity, including agro-biodiversity affects smallholders in dry-land regions by decreasing the buffering capacity of the agro-ecosystem and increasing proneness to yield variability including crop failure due to weather extremes. Loss of biodiversity is associated with land use/land co

  2. Amphibian and reptile road-kills on tertiary roads in relation to landscape structure: using a citizen science approach with open-access land cover data.

    Science.gov (United States)

    Heigl, Florian; Horvath, Kathrin; Laaha, Gregor; Zaller, Johann G

    2017-06-26

    Amphibians and reptiles are among the most endangered vertebrate species worldwide. However, little is known how they are affected by road-kills on tertiary roads and whether the surrounding landscape structure can explain road-kill patterns. The aim of our study was to examine the applicability of open-access remote sensing data for a large-scale citizen science approach to describe spatial patterns of road-killed amphibians and reptiles on tertiary roads. Using a citizen science app we monitored road-kills of amphibians and reptiles along 97.5 km of tertiary roads covering agricultural, municipal and interurban roads as well as cycling paths in eastern Austria over two seasons. Surrounding landscape was assessed using open access land cover classes for the region (Coordination of Information on the Environment, CORINE). Hotspot analysis was performed using kernel density estimation (KDE+). Relations between land cover classes and amphibian and reptile road-kills were analysed with conditional probabilities and general linear models (GLM). We also estimated the potential cost-efficiency of a large scale citizen science monitoring project. We recorded 180 amphibian and 72 reptile road-kills comprising eight species mainly occurring on agricultural roads. KDE+ analyses revealed a significant clustering of road-killed amphibians and reptiles, which is an important information for authorities aiming to mitigate road-kills. Overall, hotspots of amphibian and reptile road-kills were next to the land cover classes arable land, suburban areas and vineyards. Conditional probabilities and GLMs identified road-kills especially next to preferred habitats of green toad, common toad and grass snake, the most often found road-killed species. A citizen science approach appeared to be more cost-efficient than monitoring by professional researchers only when more than 400 km of road are monitored. Our findings showed that freely available remote sensing data in combination with a

  3. Relation of Environmental characteristics to the composition of aquatic assemblages along a gradient of urban land use in New Jersey, 1996-98

    Science.gov (United States)

    Kennen, Jonathan G.; Ayers, Mark A.

    2002-01-01

    Community data from 36 watersheds were used to evaluate the response of fish, invertebrate, and algal assemblages in New Jersey streams to environmental characteristics along a gradient of urban land use that ranged from 3 to 96 percent. Aquatic assemblages were sampled at 36 sites during 1996-98, and more than 400 environmental attributes at multiple spatial scales were summarized. Data matrices were reduced to 43, 170, and 103 species of fish, invertebrates, and algae, respectively, by means of a predetermined joint frequency and relative abundance approach. White sucker (Catostomus commersoni) and Tessellated darter (Etheostoma olmstedi) were the most abundant fishes, accounting for more than 20 and 17 percent, respectively, of the mean abundance. Net-spinning caddisflies (Hydropsychidae) were the most commonly occurring benthic invertebrates and were found at all but one of the 36 sampling sites. Blue-green (for example, Calothrix sp. and Oscillatoria sp.) and green (for example, Protoderma viride) algae were the most widely distrib-uted algae; however, more than 81 percent of the algal taxa collected were diatoms. Principal-component and correlation analyses were used to reduce the dimensionality of the environmental data. Multiple linear regression analysis of extracted ordination axes then was used to develop models that expressed effects of increasing urban land use on the structure of aquatic assemblages. Significant environmental variables identified by using multiple linear regression analysis then were included in a direct gradient analysis. Partial canonical correspondence analysis of relativized abundance data was used to restrict further the effects of residual natural variability, and to identify relations among the environmental variables and the structure of fish, invertebrate, and algal assemblages along an urban land-use gradient. Results of this approach, combined with the results of the multiple linear regression analyses, were used to

  4. Aircraft LTO emissions regulations and implementations at European airports

    Science.gov (United States)

    Yunos, Siti Nur Mariani Mohd; Ghafir, Mohammad Fahmi Abdul; Wahab, Abas Ab

    2017-04-01

    Aviation affects the environment via the emission of pollutants from aircraft, impacting human health and ecosystem. Impacts of aircraft operations at lower ground towards local air quality have been recognized. Consequently, various standards and regulations have been introduced to address the related emissions. This paper discussed both environmental regulations by focusing more on the implementations of LTO emissions charges, an incentive-based regulation introduced in Europe as an effort to fill the gap in addressing the environmental issues related to aviation.

  5. 14 CFR 25.119 - Landing climb: All-engines-operating.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Landing climb: All-engines-operating. 25... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Flight Performance § 25.119 Landing climb: All-engines-operating. In the landing configuration, the steady gradient of climb may not be less...

  6. Effects of Bacillus subtilis var. natto and Saccharomyces cerevisiae fermented liquid feed on growth performance, relative organ weight, intestinal microflora, and organ antioxidant status in Landes geese.

    Science.gov (United States)

    Chen, W; Zhu, X Z; Wang, J P; Wang, Z X; Huang, Y Q

    2013-02-01

    The aim of this study was to investigate the effect of Bacillus subtilis var. natto N21 (BAC) and Saccharomyces cerevisiae Y10 (SAC) fermented liquid feed (FLF) during different incubation times on the growth performance, relative organ weight, intestinal microflora, and organ antioxidative status in Landes geese. Two hundred forty male Landes geese (10 wk old) with the BW of 4.163 ± 0.108 kg were selected for a 3-wk trial and randomly allotted to 3 treatments according to their BW (10 replicates/treatment and 8 geese/replicate). The treatments included 1) CON, dry basal feed (corn-soybean basal diet mixed with water) before feeding (2:1 wt/wt), 2) FLF24, 24 h FLF, and 3) FLF48, 48 h FLF. The FLF diet was prepared by storing basal diet with 10(9) cfu/g feed of each BAC and SAC and water (2:1 wt/wt) in a closed tank at 20°C fermented for 24 or 48 h. The BW gain and feed intake of geese fed FLF24 and FLF48 was greater (P Feeding geese with FLF24 and FLF48 feeds increased (P feeding geese with BAC and SAC mix FLF can improve growth and feed intake, modulate the intestine ecology, and decrease the blood cholesterol concentrations; it also can improve the antioxidative status of organs and breast muscle.

  7. Relative roles of anthropogenic aerosols and greenhouse gases in land and oceanic monsoon changes during past 156 years in CMIP5 models

    Science.gov (United States)

    Zhang, Lei; Li, Tim

    2016-05-01

    Relative roles of anthropogenic aerosols (AAs) and greenhouse gases (GHGs) in land and oceanic monsoon changes during boreal summer over the period 1850-2005 in Coupled Model Intercomparison Project Phase 5 (CMIP5) models are explored. It is found that the GHG effect dominates rainfall trend over oceanic monsoon region. As a result, precipitation over western North Pacific (WNP) monsoon region and Intertropical Convergence Zone (ITCZ) over tropical eastern Pacific are strengthened through the so-called "richest-get-richer" mechanism. Over land monsoon region, GHG and AA effects are different over India and East Asia (EA). The two effects tend to offset each other over India, but the AA effect dominates over EA and induces a drying trend. The weakened effect of GHGs on EA is attributed to the large offset of thermodynamic and dynamic effects associated with GHGs. While the former tends to strengthen EA rainfall through increased moisture, the latter tends to decrease EA rainfall due to the strengthened WNP monsoon impact.

  8. CID Aircraft post-impact lakebed skid

    Science.gov (United States)

    1984-01-01

    degraders (one on each engine); and the FAA refined AMK (blending, testing, and fueling a full-size aircraft). The 15 flights had 15 takeoffs, 14 landings and a larger number of approaches to about 150 feet above the prepared crash site under remote control. These flight were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. On the final flight (No. 15) with no crew, all fuel tanks were filled with a total of 76,000 pounds of AMK and the remotely-piloted aircraft landed on Rogers Dry Lakebed in an area prepared with posts to test the effectiveness of the AMK in a controlled impact. The CID, which some wags called the Crash in the Desert, was spectacular with a large fireball enveloping and burning the B-720 aircraft. From the standpoint of AMK the test was a major set-back, but for NASA Langley, the data collected on crashworthiness was deemed successful and just as important.

  9. 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 covered...

  10. Multi-camera networks for motion parameter estimation of an aircraft

    Directory of Open Access Journals (Sweden)

    Banglei Guan

    2017-02-01

    Full Text Available A multi-camera network is proposed to estimate an aircraft’s motion parameters relative to the reference platform in large outdoor fields. Multiple cameras are arranged to cover the aircraft’s large-scale motion spaces by field stitching. A camera calibration method using dynamic control points created by a multirotor unmanned aerial vehicle is presented under the conditions that the field of view of the cameras is void. The relative deformation of the camera network caused by external environmental factors is measured and compensated using a combination of cameras and laser rangefinders. A series of field experiments have been carried out using a fixed-wing aircraft without artificial makers, and its accuracy is evaluated using an onboard Differential Global Positioning System. The experimental results show that the multi-camera network is precise, robust, and highly dynamic and can improve the aircraft’s landing accuracy.

  11. Proposed Rule and Related Materials for Proposed Finding That Greenhouse Gas Emissions From Aircraft Cause or Contribute to Air Pollution That May Reasonably Be Anticipated To Endanger Public Health and Welfare and Advance Notice of Proposed Rulemaking

    Science.gov (United States)

    FR notice and fact sheet concerning Advance Notice of Proposed Rulemaking that provides information on the process for setting an international CO2 emissions standard for aircraft at the International Civil Aviation Organization (ICAO)

  12. Guidance Systems of Fighter Aircraft

    Directory of Open Access Journals (Sweden)

    K.N. Rajanikanth

    2005-07-01

    Full Text Available Mission performance of a fighter aircraft is crucial for survival and strike capabilities in todays' aerial warfare scenario. The guidance functions of such an aircraft play a vital role inmeeting the requirements and accomplishing the mission success. This paper presents the requirements of precision guidance for various missions of a fighter aircraft. The concept ofguidance system as a pilot-in-loop system is pivotal in understanding and designing such a system. Methodologies of designing such a system are described.

  13. Guidance Systems of Fighter Aircraft

    OpenAIRE

    K.N. Rajanikanth; Rao, R S; P. S. Subramanyam; Ajai Vohra

    2005-01-01

    Mission performance of a fighter aircraft is crucial for survival and strike capabilities in todays' aerial warfare scenario. The guidance functions of such an aircraft play a vital role inmeeting the requirements and accomplishing the mission success. This paper presents the requirements of precision guidance for various missions of a fighter aircraft. The concept ofguidance system as a pilot-in-loop system is pivotal in understanding and designing such a system. Methodologies of designing s...

  14. Does Traffic-related Air Pollution Explain Associations of Aircraft and Road Traffic Noise Exposure on Children's Health and Cognition? A Secondary Analysis of the United Kingdom Sample From the RANCH Project

    OpenAIRE

    Clark, Charlotte; Crombie, Rosanna; Head, Jenny; van Kamp, Irene; Kempen, Elise van; Stansfeld, Stephen A.

    2012-01-01

    The authors examined whether air pollution at school (nitrogen dioxide) is associated with poorer child cognition and health and whether adjustment for air pollution explains or moderates previously observed associations between aircraft and road traffic noise at school and children's cognition in the 2001–2003 Road Traffic and Aircraft Noise Exposure and Children's Cognition and Health (RANCH) project. This secondary analysis of a subsample of the United Kingdom RANCH sample examined 719 chi...

  15. Scheduling of an aircraft fleet

    Science.gov (United States)

    Paltrinieri, Massimo; Momigliano, Alberto; Torquati, Franco

    1992-01-01

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

  16. Intercomparison results for FIFE flux aircraft

    Science.gov (United States)

    Macpherson, J. I.; Grossman, R. L.; Kelly, R. D.

    1992-01-01

    Three atmospheric research aircraft were used to explore the atmospheric boundary layer during FIFE: the National Research Council of Canada Twin Otter, the National Center for Atmospheric Research (NCAR) King Air, and the University of Wyoming King Air. The aircraft were used to measure the mean and turbulent structure of the boundary layer and its variation with height, time, and space. These measurements are important to FIFE because they are being used to scale up point surface observations to landscape scales and because they can be used to relate satellite radiance measurements to boundary layer processes. Because the aircraft were used in coordinated flight patterns to investigate changes within and between intensive field campaigns, wing-to-wing intercomparisons were made so that measurements from one aircraft could be related to another. Intercomparisons were flown on 4 days in 1987 and 3 days in 1989. The eddy correlation measurements of the mixed layer fluxes of moisture and sensible heat were of particular interest to FIFE. Sensible heat fluxes agreed within 15 W/sq m and moisture fluxes agreed within 21 W/sq m. Mean wind component differences were within 1.0 m/s, air temperature within 0.3 C, and mixing ratio within 2 g/kg. Standard deviations showed similar good agreement, with mean differences generally less than 0.1 m/s for the wind components and 0.03 C for potential temperature. Intercomparisons between the NCAR King Air and the Twin Otter showed better agreement in 1989 than in 1987. Overall, the results suggest that data from the FIFE boundary layer aircraft will need little correction to account for instrument biases and spurious fluctuations.

  17. Aerodynamic Measurements of a Gulfstream Aircraft Model With and Without Noise Reduction Concepts

    Science.gov (United States)

    Neuhart, Dan H.; Hannon, Judith A.; Khorrami, Mehdi R.

    2014-01-01

    Steady and unsteady aerodynamic measurements of a high-fidelity, semi-span 18% scale Gulfstream aircraft model are presented. The aerodynamic data were collected concurrently with acoustic measurements as part of a larger aeroacoustic study targeting airframe noise associated with main landing gear/flap components, gear-flap interaction noise, and the viability of related noise mitigation technologies. The aeroacoustic tests were conducted in the NASA Langley Research Center 14- by 22-Foot Subsonic Wind Tunnel with the facility in the acoustically treated open-wall (jet) mode. Most of the measurements were obtained with the model in landing configuration with the flap deflected at 39º and the main landing gear on and off. Data were acquired at Mach numbers of 0.16, 0.20, and 0.24. Global forces (lift and drag) and extensive steady and unsteady surface pressure measurements were obtained. Comparison of the present results with those acquired during a previous test shows a significant reduction in the lift experienced by the model. The underlying cause was traced to the likely presence of a much thicker boundary layer on the tunnel floor, which was acoustically treated for the present test. The steady and unsteady pressure fields on the flap, particularly in the regions of predominant noise sources such as the inboard and outboard tips, remained unaffected. It is shown that the changes in lift and drag coefficients for model configurations fitted with gear/flap noise abatement technologies fall within the repeatability of the baseline configuration. Therefore, the noise abatement technologies evaluated in this experiment have no detrimental impact on the aerodynamic performance of the aircraft model.

  18. Palaeoenvironments and changes in relative sea level during the last interglaciation at Langelandselv, Jameson Land, East Greenland

    DEFF Research Database (Denmark)

    Vosgerau, H.; Funder, Svend Visby; Kelly, M.

    1994-01-01

    -barrier, and delta environments during a rise in the relative sea level from 0 to 18 m. The interglacial succession ends with glaciotectonically dislocated fluvial sand, and is capped by alternating beds of lodgement till and fluvial sand, deposited during the Early Weichselian. The age is determined...... by palacoceanographic correlation of molluse and foraminifer faunas with isotopic substage 5e in the deep sea record, supported by luminescencs and U/Th dates and amino acid analysis....

  19. Global Tracking Control of Quadrotor VTOL Aircraft in Three-Dimensional Space

    Directory of Open Access Journals (Sweden)

    Duc Khac Do

    2014-07-01

    Full Text Available This paper presents a method to design controllers that force a quadrotor vertical take-off and landing (VTOL aircraft to globally asymptotically track a reference trajectory in three-dimensional space. Motivated by the vehicle's steering practice, the roll and pitch angles are considered as immediate controls plus the total thrust force  provided by the aircraft's four rotors to control the position and yaw angle of the aircraft. The control design is based on the newly introduced one-step ahead backstepping, the standard backstepping and Lyapunov's direct methods. A combination of Euler angles and unit-quaternion for the attitude representation of the aircraft is used to obtain global tracking control results. The paper also includes a design of observers that exponentially estimate the aircraft's linear velocity vector and disturbances. Simulations illustrate the results.

  20. Information fusion based optimal control for large civil aircraft system.

    Science.gov (United States)

    Zhen, Ziyang; Jiang, Ju; Wang, Xinhua; Gao, Chen

    2015-03-01

    Wind disturbance has a great influence on landing security of Large Civil Aircraft. Through simulation research and engineering experience, it can be found that PID control is not good enough to solve the problem of restraining the wind disturbance. This paper focuses on anti-wind attitude control for Large Civil Aircraft in landing phase. In order to improve the riding comfort and the flight security, an information fusion based optimal control strategy is presented to restrain the wind in landing phase for maintaining attitudes and airspeed. Data of Boeing707 is used to establish a nonlinear mode with total variables of Large Civil Aircraft, and then two linear models are obtained which are divided into longitudinal and lateral equations. Based on engineering experience, the longitudinal channel adopts PID control and C inner control to keep longitudinal attitude constant, and applies autothrottle system for keeping airspeed constant, while an information fusion based optimal regulator in the lateral control channel is designed to achieve lateral attitude holding. According to information fusion estimation, by fusing hard constraint information of system dynamic equations and the soft constraint information of performance index function, optimal estimation of the control sequence is derived. Based on this, an information fusion state regulator is deduced for discrete time linear system with disturbance. The simulation results of nonlinear model of aircraft indicate that the information fusion optimal control is better than traditional PID control, LQR control and LQR control with integral action, in anti-wind disturbance performance in the landing phase. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Airdrop of Armament and Military Equipment from Aircraft

    Directory of Open Access Journals (Sweden)

    Dražen Kovačević

    2012-10-01

    Full Text Available Air supply can be performed in two ways: by transportingthe technical equipment by transport aircraft or helicopters,and unloading upon landing and by air-dropping. The airdropcan be performed by dropping without parachutes, with parachutesand by low altitude cargo extraction. In the USA- CADS(Controlled Aerial Delivery System has been developed providingcontrol of the falling cargo via a remote controller.

  2. Integration of Predictive Display and Aircraft Flight Control System

    Directory of Open Access Journals (Sweden)

    Efremov A.V.

    2017-01-01

    Full Text Available The synthesis of predictive display information and direct lift control system are considered for the path control tracking tasks (in particular landing task. The both solutions are based on pilot-vehicle system analysis and requirements to provide the highest accuracy and lowest pilot workload. The investigation was carried out for cases with and without time delay in aircraft dynamics. The efficiency of the both ways for the flying qualities improvement and their integration is tested by ground based simulation.

  3. Perspectives on Unmanned Aircraft Classification for Civil Airworthiness Standards

    Science.gov (United States)

    Maddalon, Jeffrey M.; Hayhurst, Kelly J.; Koppen, Daniel M.; Upchurch, Jason M.; Morris, A. Terry; Verstynen, Harry A.

    2013-01-01

    The use of unmanned aircraft in the National Airspace System (NAS) has been characterized as the next great step forward in the evolution of civil aviation. Although use of unmanned aircraft systems (UAS) in military and public service operations is proliferating, civil use of UAS remains limited in the United States today. This report focuses on one particular regulatory challenge: classifying UAS to assign airworthiness standards. This paper provides observations related to how the current regulations for classifying manned aircraft could apply to UAS.

  4. Relation between seasonally detrended shortwave infrared reflectance data and land surface moisture in semi-arid Sahel

    DEFF Research Database (Denmark)

    Olsen, Jørgen Lundegaard; Ceccato, Pietro; Proud, Simon Richard

    2013-01-01

    in vegetation moisture status, and is compared to detrended time series of the Normalized Difference Vegetation Index (NDVI). It was found that when plant available water is low, the SIWSI anomalies increase over time, while the NDVI anomalies decrease over time, but less systematically. Therefore SIWSI may...... carry important complementary information to NDVI in terms of vegetation water status, and can provide this information with the unique combination of temporal and spatial resolution from optical geostationary observations over Sahel. However, the relation between SIWSI anomalies and periods of water...

  5. Commercial Aircraft Protection

    Energy Technology Data Exchange (ETDEWEB)

    Ehst, David A. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-10-26

    This report summarizes the results of theoretical research performed during 3 years of P371 Project implementation. In results of such research a new scientific conceptual technology of quasi-passive individual infrared protection of heat-generating objects – Spatial Displacement of Thermal Image (SDTI technology) was developed. Theoretical substantiation and description of working processes of civil aircraft individual IR-protection system were conducted. The mathematical models and methodology were presented, there were obtained the analytical dependencies which allow performing theoretical research of the affect of intentionally arranged dynamic field of the artificial thermal interferences with variable contrast onto main parameters of optic-electronic tracking and homing systems.

  6. Chemistry in aircraft plumes

    Energy Technology Data Exchange (ETDEWEB)

    Kraabol, A.G.; Stordal, F.; Knudsen, S. [Norwegian Inst. for Air Research, Kjeller (Norway); Konopka, P. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    An expanding plume model with chemistry has been used to study the chemical conversion of NO{sub x} to reservoir species in aircraft plumes. The heterogeneous conversion of N{sub 2}O{sub 5} to HNO{sub 3}(s) has been investigated when the emissions take place during night-time. The plume from an B747 has been simulated. During a ten-hour calculation the most important reservoir species was HNO{sub 3} for emissions at noon. The heterogeneous reactions had little impact on the chemical loss of NO{sub x} to reservoir species for emissions at night. (author) 4 refs.

  7. Hydrogen aircraft technology

    Science.gov (United States)

    Brewer, G. D.

    1991-01-01

    A comprehensive evaluation is conducted of the technology development status, economics, commercial feasibility, and infrastructural requirements of LH2-fueled aircraft, with additional consideration of hydrogen production, liquefaction, and cryostorage methods. Attention is given to the effects of LH2 fuel cryotank accommodation on the configurations of prospective commercial transports and military airlifters, SSTs, and HSTs, as well as to the use of the plentiful heatsink capacity of LH2 for innovative propulsion cycles' performance maximization. State-of-the-art materials and structural design principles for integral cryotank implementation are noted, as are airport requirements and safety and environmental considerations.

  8. Aircraft propeller control

    Science.gov (United States)

    Day, Stanley G. (Inventor)

    1990-01-01

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

  9. Resilient Propulsion Control Research for the NASA Integrated Resilient Aircraft Control (IRAC) Project

    Science.gov (United States)

    Guo, Ten-Huei; Litt, Jonathan S.

    2007-01-01

    Gas turbine engines are designed to provide sufficient safety margins to guarantee robust operation with an exceptionally long life. However, engine performance requirements may be drastically altered during abnormal flight conditions or emergency maneuvers. In some situations, the conservative design of the engine control system may not be in the best interest of overall aircraft safety; it may be advantageous to "sacrifice" the engine to "save" the aircraft. Motivated by this opportunity, the NASA Aviation Safety Program is conducting resilient propulsion research aimed at developing adaptive engine control methodologies to operate the engine beyond the normal domain for emergency operations to maximize the possibility of safely landing the damaged aircraft. Previous research studies and field incident reports show that the propulsion system can be an effective tool to help control and eventually land a damaged aircraft. Building upon the flight-proven Propulsion Controlled Aircraft (PCA) experience, this area of research will focus on how engine control systems can improve aircraft safe-landing probabilities under adverse conditions. This paper describes the proposed research topics in Engine System Requirements, Engine Modeling and Simulation, Engine Enhancement Research, Operational Risk Analysis and Modeling, and Integrated Flight and Propulsion Controller Designs that support the overall goal.

  10. Aircraft vulnerability analysis by modelling and simulation

    CSIR Research Space (South Africa)

    Willers, CJ

    2014-09-01

    Full Text Available attributable to misuse of the weapon or to missile performance restrictions. This paper analyses some of the factors affecting aircraft vulnerability and demonstrates a structured analysis of the risk and aircraft vulnerability problem. The aircraft...

  11. Federal Lands

    Data.gov (United States)

    Department of Homeland Security — This map layer consists of federally owned or administered lands of theUnited States, Puerto Rico, and the U.S. Virgin Islands. Only areas of 640 acres or more are...

  12. Land Resources

    Science.gov (United States)

    Young, Anthony

    1998-08-01

    Unless action is taken, the developing world will face recurrent problems of food security and conflict. This volume provides a summary and perspective of the field of land resources and suggests improvements needed to conserve resources for future generations. Coverage provides an authoritative review of the resources of soils, water, climate, forests and pastures on which agriculture depends. It assesses the interactions between land resources and wider aspects of development, including population and poverty. It provides a strong critique of current methods of assessing land degradation and placing an economic value on land. It should be read by all involved in rural development, including scientists, economists, geographers, sociologists, planners, and students of development studies.

  13. Residual Stress Analysis of Aircraft Part using Neutron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Eun Joo; Seong, Baek Seok; Sim, Cheul Muu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    A precise measurement of the residual stress magnitude and distribution is an important factor to evaluate the lifetime or safety of the materials, because the residual stress affects the material properties, such as the strength, fatigue, etc. In the case of a fighter jet, the lifetime and safety of the parts of the landing gear are more important than that of a passenger airplane because of its frequent take offs and landings. In particular in the case of training a fighter jet, a precise evaluation of life time for the parts of the landing gear is strongly required for economic reason. In this study, the residual stress of a part of the landing gear of the training fighter jet which is used to fix the landing gear to the aircraft body was investigated. The part was used for 2000 hours of flight, which corresponds to 10 years. During this period, the fighter jet normally takes off and lands more than 2000 times. These frequent take off and landing can generate residual stress and cause a crack in the part. By measuring the neutron diffraction peaks, we evaluated the residual stress of the landing gear part

  14. Mastery, perceived stress and health-related behaviour in northeast Arnhem Land: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Brown Alex

    2006-09-01

    Full Text Available Abstract Background Indigenous peoples in Australia are disadvantaged on all markers of health and social status across the life course. Psychosocial factors are implicated in the aetiology of chronic diseases and in pathways underpinning social health disparities. Minimal research has investigated psychosocial factors and health in Indigenous peoples. This study evaluated associations between mastery, perceived stress, and health-related behaviour for a remote Indigenous population in Australia. Methods Complete data on mastery (the degree to which individuals feel in control of their lives, perceived stress, physical activity, and fruit and vegetable consumption were obtained for 177 participants in a community-based chronic disease risk factor survey. Psychosocial questionnaires were completed as an option during community screening (response rate = 61.9%. Extensive consultation facilitated the cross-cultural adaptation of measures. Results Mastery was inversely correlated with perceived stress measures (p r = -0.47; chronic stress, r = -0.41; and youth stress, r = -0.30. Relationships between mastery and behaviour varied according to age group (p = 0.001 and vegetable consumption (p = 0.005. Individuals aged ≥25 years engaging in ≤2 bouts of physical activity/week had lower mastery than individuals engaging in ≥3 bouts/week, with means (95% CI of 14.8 (13.7–15.8 and 17.1 (15.3–19.0, respectively (p = 0.026. Individuals aged ≥25 years eating vegetables ≤3 times/week had lower mastery than those eating vegetables ≥4 times/week (p = 0.009 [means 14.7 (13.8–15.5 and 17.3 (15.5–19.1, respectively]. Individuals p = 0.022 [means 17.2 (15.2–19.2 and 13.8 (11.9–15.7, respectively]. For men ≥25 years and women ≥15 years, mastery was inversely related to age (p p = 0.001 [means 13.4 (12.1–14.7 and 17.5 (15.3–19.8, respectively]. Conclusion Consistent with previous research, this study provides additional support for a

  15. Trajectory Optimization of Electric Aircraft Subject to Subsystem Thermal Constraints

    Science.gov (United States)

    Falck, Robert D.; Chin, Jeffrey C.; Schnulo, Sydney L.; Burt, Jonathan M.; Gray, Justin S.

    2017-01-01

    Electric aircraft pose a unique design challenge in that they lack a simple way to reject waste heat from the power train. While conventional aircraft reject most of their excess heat in the exhaust stream, for electric aircraft this is not an option. To examine the implications of this challenge on electric aircraft design and performance, we developed a model of the electric subsystems for the NASA X-57 electric testbed aircraft. We then coupled this model with a model of simple 2D aircraft dynamics and used a Legendre-Gauss-Lobatto collocation optimal control approach to find optimal trajectories for the aircraft with and without thermal constraints. The results show that the X-57 heat rejection systems are well designed for maximum-range and maximum-efficiency flight, without the need to deviate from an optimal trajectory. Stressing the thermal constraints by reducing the cooling capacity or requiring faster flight has a minimal impact on performance, as the trajectory optimization technique is able to find flight paths which honor the thermal constraints with relatively minor deviations from the nominal optimal trajectory.

  16. Aircraft family design using enhanced collaborative optimization

    Science.gov (United States)

    Roth, Brian Douglas

    Significant progress has been made toward the development of multidisciplinary design optimization (MDO) methods that are well-suited to practical large-scale design problems. However, opportunities exist for further progress. This thesis describes the development of enhanced collaborative optimization (ECO), a new decomposition-based MDO method. To support the development effort, the thesis offers a detailed comparison of two existing MDO methods: collaborative optimization (CO) and analytical target cascading (ATC). This aids in clarifying their function and capabilities, and it provides inspiration for the development of ECO. The ECO method offers several significant contributions. First, it enhances communication between disciplinary design teams while retaining the low-order coupling between them. Second, it provides disciplinary design teams with more authority over the design process. Third, it resolves several troubling computational inefficiencies that are associated with CO. As a result, ECO provides significant computational savings (relative to CO) for the test cases and practical design problems described in this thesis. New aircraft development projects seldom focus on a single set of mission requirements. Rather, a family of aircraft is designed, with each family member tailored to a different set of requirements. This thesis illustrates the application of decomposition-based MDO methods to aircraft family design. This represents a new application area, since MDO methods have traditionally been applied to multidisciplinary problems. ECO offers aircraft family design the same benefits that it affords to multidisciplinary design problems. Namely, it simplifies analysis integration, it provides a means to manage problem complexity, and it enables concurrent design of all family members. In support of aircraft family design, this thesis introduces a new wing structural model with sufficient fidelity to capture the tradeoffs associated with component

  17. Carbon distributions in Spartina alterniflora dominated salt marshes in Galveston, Texas: The role of elevation, relative sea level history, and land cover conversions

    Science.gov (United States)

    Kulawardhana, R. W.; Feagin, R. A.; Popescu, S. C.

    2014-12-01

    Coastal wetlands, including salt marshes, are considered to be large carbon sinks. Yet, there is little knowledge about how the terrain and land cover of these environments are related to carbon distribution. An understanding of the spatial and temporal patterns of carbon held in both the biomass and soil, and the factors that influence its distribution, will be necessary to allow coastal managers to initiate and verify "Blue Carbon" projects. In this study, we attempt to understand: 1) the temporal changes in salt marsh distributions as affected by marsh submergence, vertical accretion and land cover conversions; 2) patterns of soil carbon across different depths of the soil profile; and 3) to evaluate how changes in relative water level governs the spatial and temporal variability of salt marsh carbon storage ability. Our results indicate that over the study period (1954 to present) a considerable portion of salt marsh extents were submerged, while at the higher terrains these salt marshes indicated a landward shift in response to the sea level rise. Soil carbon measured in the soil profile, revealed a gradual depletion of soil carbon with depth. However, both the soil bulk density and the percent carbon indicated an abrupt and significant change at a depth of 15cm (p=0.05), which we interpreted as distinct of two different environments. As evidenced by historical aerial imagery (1954, 1969), the first (15-30 cm depth) coincided with an unvegetated salt flat at the sample locations, which were then overlain by lower bulk density and higher carbon Spartina alterniflora low marsh (0-15 cm depth) that migrated upslope in response to rapid relative sea level rise. However, within each of these two environments separately, carbon distribution followed a unique pattern with respect to elevation. Our results further point to two different processes, each acting at a different time scale (daily tides versus relative sea level rise), and each results in distinct spatial

  18. Auralization of novel aircraft configurations

    NARCIS (Netherlands)

    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.

  19. 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.

  20. A Site-Related Suitability Analysis for the Production of Biomass as a Contribution to Sustainable Regional Land-Use

    Science.gov (United States)

    Förster, Michael; Helms, Yvonne; Herberg, Alfred; Köppen, Antje; Kunzmann, Kathrin; Radtke, Dörte; Ross, Lutz; Itzerott, Sibylle

    2008-04-01

    The use of renewable energy in Europe offers the possibility of reducing greenhouse gas emissions, and contributes to energy security and independence. With the reform of the Common Agricultural Policy (CAP) and a variety of recently introduced national directives supporting renewable energy sources in the European Union, the economic attractiveness of bioenergy production has distinctly increased. This article combines an economic evaluation of biomass production with site-related natural conditions of the Havelland region, situated in the north-east area of Germany. Two methods for evaluating site-specific potential biomass yields were compared. For three example biomass crops, evaluations of yield estimations at agricultural lots for site-optimized suitability (SOS) and conventional suitability (CS) were carried out. Both modelling approaches were compared. The results of the GIS modelling indicate that the financial support for increasing the use of renewable energy with the German feed-in system, called Erneuerbare-Energien-Gesetz (EEG), will possibly lead to an increased cultivation of crops with high biomass output. This monocultural orientation of farming practices and the negative effects on the ecosystem could act in opposition to other environmental initiatives of the EU. The outputs of the SOS analysis show that high biomass production could be integrated into environmental policy proposals. Therefore, new EU policy should take modified subsidies into consideration in order to avoid developing conflicts between small-scale changes in landscape ecosystems caused by large-scale transformations in energy policy.