Science.gov

Sample records for ahs maneuver definition

  1. Experimental Analysis of Steady-State Maneuvering Effects on Transmission Vibration Patterns Recorded in an AH-1 Cobra Helicopter

    NASA Technical Reports Server (NTRS)

    Huff, Edward M.; Dzwonczyk, Mark; Norvig, Peter (Technical Monitor)

    2000-01-01

    Flight experiment was designed primarily to determine the extent to which steady-state maneuvers influence characteristic vibration patterns measured at the input pinion and output annulus gear locations of the main transmission. If results were to indicate that maneuvers systematically influence vibration patterns, more extensive studies would be planned to explore the response surface. It was also designed to collect baseline data for comparison with experimental data to be recorded at a later date from test stands at Glenn Research Center. Finally, because this was the first vibration flight study on the Cobra aircraft, considerable energy was invested in developing an in-flight recording apparatus, as well as exploring acceleration mounting methods, and generally learning about the overall vibratory characteristics of the aircraft itself.

  2. Manned maneuvering unit mission definition study. Volume 1: MMU applications analysis and performance requirements

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Applications of Manned Maneuvering Units (MMU'S) to the space shuttle program are identified and described. The applications analyses included studies of the shuttle orbiter, orbiter subsystems, and both Sortie and Automated Payloads. Based on practicable MMU applications, general performance and control requirements for shuttle supporting maneuvering units are defined and compared to units evaluated on Skylab. The results of the MMU applications analyses and the general MMU performance and control requirements are presented. To describe a versatile utility-type maneuvering unit, conceptual designs of MMU support subsystems and ancillary equipment were prepared. Concepts for attaching and securing the MMU crewman to various vehicles, structure configurations, and rescue systems were developed. Concepts for ancillary provisions are reported.

  3. Manned maneuvering unit mission definition study. Volume 2: Appendices to the MMU applications analysis

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Information used in identifying representative Manned Maneuvering Unit (MMU) from the many Automated and Sortie Payloads and orbiter subsystems is presented. Representative missions were selected to represent typical MMU applications across all payloads and orbiter subsystems. Data analysis sheets are provided with other applicable information. Calculations used in defining MMU general performance and control requirements to satisfy eleven space missions are included.

  4. Manned maneuvering unit mission definition study. Volume 3: MMU ancillary support equipment and attachment concepts

    NASA Technical Reports Server (NTRS)

    1975-01-01

    An analysis of Manned Maneuvering Units (MMU) ancillary support equipment and attachment concepts is presented. The major objectives of the study are defined as: (1) identifying MMU applications which would supplement space shuttle safety and effectiveness, (2) to define general MMU performance and control requirements to satisfy candidate shuttle applications, (3) to develop concepts for attaching MMUs to various worksites and equipment, and (4) to identify requirements and develop concepts for MMU ancillary equipment.

  5. A proposed definition for a pitch attitude target for the microburst escape maneuver

    NASA Technical Reports Server (NTRS)

    Bray, Richard S.

    1990-01-01

    The Windshear Training Aid promulgated by the Federal Aviation Administration (FAA) defines the practical recovery maneuver following a microburst encounter as application of maximum thrust accompanied by rotation to an aircraft-specific target pitch attitude. In search of a simple method of determining this target, appropriate to a variety of aircraft types, a computer simulation was used to explore the suitability of a pitch target equal in numerical value to that of the angle of attack associated with stall warning. For the configurations and critical microburst shears simulated, this pitch target was demonstrated to be close to optimum.

  6. Maneuvering PMHTs

    NASA Astrophysics Data System (ADS)

    Ruan, Yanhua; Willett, Peter K.

    2001-11-01

    The Probabilistic Multiple Hypothesis Tracker (PMHT) has previously been augmented and modified to deal with target maneuver. Unfortunately, although the resulting procedure tracks maneuvering targets reasonably well, estimation of the maneuver process (i.e. the hidden Markov Model (HMM)) is not particularly reactive. In this paper, the PMHT is further investigated and several PMHT variants for maneuvering targets are discussed these include the ideas from Logothetis et al. and from Pulford and La Scala; the incorporation of the Interacting Multiple Mode (IMM) formalism to the PMHT; the extension of the "turbo" PMHT. We finally compare these EM-based tracking schemes and provide the simulation results on the second benchmark problem from Blair et al.

  7. Terra Maneuvers

    Atmospheric Science Data Center

    2013-03-12

    ... Loss of Pointing Accuracy 58983 022 0.00 00:00:08.2 ... 63452 228 2011/326/16:33:41 Regain Pointing Accuracy 63453 011 ... 2008/263/23:12:59 MODIS Roll Maneuver #83 46573 211 2008/263/12:17:00 ...

  8. Maneuver Automation Software

    NASA Technical Reports Server (NTRS)

    Uffelman, Hal; Goodson, Troy; Pellegrin, Michael; Stavert, Lynn; Burk, Thomas; Beach, David; Signorelli, Joel; Jones, Jeremy; Hahn, Yungsun; Attiyah, Ahlam; Illsley, Jeannette

    2009-01-01

    The Maneuver Automation Software (MAS) automates the process of generating commands for maneuvers to keep the spacecraft of the Cassini-Huygens mission on a predetermined prime mission trajectory. Before MAS became available, a team of approximately 10 members had to work about two weeks to design, test, and implement each maneuver in a process that involved running many maneuver-related application programs and then serially handing off data products to other parts of the team. MAS enables a three-member team to design, test, and implement a maneuver in about one-half hour after Navigation has process-tracking data. MAS accepts more than 60 parameters and 22 files as input directly from users. MAS consists of Practical Extraction and Reporting Language (PERL) scripts that link, sequence, and execute the maneuver- related application programs: "Pushing a single button" on a graphical user interface causes MAS to run navigation programs that design a maneuver; programs that create sequences of commands to execute the maneuver on the spacecraft; and a program that generates predictions about maneuver performance and generates reports and other files that enable users to quickly review and verify the maneuver design. MAS can also generate presentation materials, initiate electronic command request forms, and archive all data products for future reference.

  9. Rotor noise in maneuvering flight

    NASA Astrophysics Data System (ADS)

    Chen, Hsuan-Nien

    The objective of this research is to understand the physics of rotor noise in the maneuvering flight. To achieve this objective, an integrated noise prediction system is constructed, namely GenHel-MFW-PSU-WOPWOP. This noise prediction system includes a flight simulation code, a high fidelity free vortex-wake code, and a rotor acoustic prediction code. By using this noise prediction system, rotor maneuver noise characteristics are identified. Unlike periodic rotor noise, a longer duration is required to describe rotor maneuver noise. The variation of helicopter motion, blade motion and blade airloads are all influencing the noise prediction results in both noise level and directivity in the maneuvering flight. In this research, two types of rotor maneuver noise are identified, steady maneuver noise and transient maneuver noise. In the steady maneuver, rotor noise corresponds to a steady maneuver condition, which has nearly steady properties in flight dynamics and aerodynamics. Transient maneuver noise is the result of the transition between two steady maneuvers. In a transient maneuver, the helicopter experiences fluctuations in airload and helicopter angular rates, which lead to excess rotor noise. Even though the transient maneuver only exists for a fairly short period of time, the corresponding transient maneuver noise could be significant when compared to steady maneuver noise. The blade tip vortices also present complex behaviors in the transient maneuver condition. With stronger vortex circulation strength and the potential for vortex bundling, blade vortex-interaction (BVI) noise may increase significantly during a transient maneuver. In this research, it is shown that even with small pilot controls, significant BVI noise can be generated during a transient flight condition. Finally, through this research, the importance of transient maneuver noise is demonstrated and recognized.

  10. "Jum'ah" syndrome.

    PubMed

    Kannai, Ruth

    2012-05-01

    This is my memoir as a sick child, hospitalized in the Pediatric ward of a large hospital, many years ago. The story tells about my friendship with another young patient, Jum'ah, a Bedouin child who suffered from Congenital Cyanotic Heart Disease, to whom the pediatric ward was Home. My Childish understanding of Jum'ah's loneliness, anxiety and struggle to be loved and belonged are described in this narrative. I describe how this experience still has an influence on my adult professional and personal concepts. PMID:21943791

  11. Orbital Maneuvering system design evolution

    NASA Technical Reports Server (NTRS)

    Gibson, C.; Humphries, C.

    1985-01-01

    Preliminary design considerations and changes made in the baseline space shuttle orbital maneuvering system (OMS) to reduce cost and weight are detailed. The definition of initial subsystem requirements, trade studies, and design approaches are considered. Design features of the engine, its injector, combustion chamber, nozzle extension and bipropellant valve are illustrated and discussed. The current OMS consists of two identical pods that use nitrogen tetroxide (NTO) and monomethylhydrazine (MMH) propellants to provide 1000 ft/sec of delta velocity for a payload of 65,000 pounds. Major systems are pressurant gas storage and control, propellant storage supply and quantity measurement, and the rocket engine, which includes a bipropellant valve, an injector/thrust chamber, and a nozzle. The subsystem provides orbit insertion, circularization, and on orbit and deorbit capability for the shuttle orbiter.

  12. Instantaneous Observability of Tightly Coupled SINS/GPS during Maneuvers

    PubMed Central

    Jiang, Junxiang; Yu, Fei; Lan, Haiyu; Dong, Qianhui

    2016-01-01

    The tightly coupled strapdown inertial navigation system (SINS)/global position system (GPS) has been widely used. The system observability determines whether the system state can be estimated by a filter efficiently or not. In this paper, the observability analysis of a two-channel and a three-channel tightly coupled SINS/GPS are performed, respectively, during arbitrary translational maneuvers and angle maneuvers, where the translational maneuver and angle maneuver are modeled. A novel instantaneous observability matrix (IOM) based on a reconstructed psi-angle model is proposed to make the theoretical analysis simpler, which starts from the observability definition directly. Based on the IOM, a series of theoretical analysis are performed. Analysis results show that almost all kinds of translational maneuver and angle maneuver can make a three-channel system instantaneously observable, but there is no one translational maneuver or angle maneuver can make a two-channel system instantaneously observable. The system’s performance is investigated when the system is not instantaneously observable. A series of simulation studies based on EKF are performed to confirm the analytic conclusions. PMID:27240369

  13. Instantaneous Observability of Tightly Coupled SINS/GPS during Maneuvers.

    PubMed

    Jiang, Junxiang; Yu, Fei; Lan, Haiyu; Dong, Qianhui

    2016-01-01

    The tightly coupled strapdown inertial navigation system (SINS)/global position system (GPS) has been widely used. The system observability determines whether the system state can be estimated by a filter efficiently or not. In this paper, the observability analysis of a two-channel and a three-channel tightly coupled SINS/GPS are performed, respectively, during arbitrary translational maneuvers and angle maneuvers, where the translational maneuver and angle maneuver are modeled. A novel instantaneous observability matrix (IOM) based on a reconstructed psi-angle model is proposed to make the theoretical analysis simpler, which starts from the observability definition directly. Based on the IOM, a series of theoretical analysis are performed. Analysis results show that almost all kinds of translational maneuver and angle maneuver can make a three-channel system instantaneously observable, but there is no one translational maneuver or angle maneuver can make a two-channel system instantaneously observable. The system's performance is investigated when the system is not instantaneously observable. A series of simulation studies based on EKF are performed to confirm the analytic conclusions. PMID:27240369

  14. AH Her Observing Campaign

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2013-05-01

    Dr. Juan Echevarria (Universidad Nacional Autónoma de México) and colleagues request AAVSO assistance in a campaign on the Z Cam-type cataclysmic variable AH Her being carried out 2013 May 29 - June 18. They will be making photometric and spectroscopic observations of AH Her using the 2.1m and 0.84m telescopes at San Pedro Martir Observatory (SPM). Their goal is to carry out a radial velocity study of the system components using modern detectors; no study of AH Her has been made since the one by Horne, Wade, and Szkody in 1980-1981 (1986MNRAS.219..791H). Photometry and spectroscopy are requested. AH Her, for decades a reasonably "regular" Z Cam system, began exhibiting significantly anomalous behavior in ~2007. Since then it has experienced brief periods of fairly typical behavior interspersed with more anomalous intervals, including some unprecedented behavior. Most recently, it has returned to a more normal pattern of outbursts shape-wise but it is not back to its normal amplitude or frequency. AAVSO data will be essential for correlation in order to determine the precise time(s) of minimum occurring during the campaign. Finder charts with sequences may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  15. Maneuvers during legged locomotion

    NASA Astrophysics Data System (ADS)

    Jindrich, Devin L.; Qiao, Mu

    2009-06-01

    Maneuverability is essential for locomotion. For animals in the environment, maneuverability is directly related to survival. For humans, maneuvers such as turning are associated with increased risk for injury, either directly through tissue loading or indirectly through destabilization. Consequently, understanding the mechanics and motor control of maneuverability is a critical part of locomotion research. We briefly review the literature on maneuvering during locomotion with a focus on turning in bipeds. Walking turns can use one of several different strategies. Anticipation can be important to adjust kinematics and dynamics for smooth and stable maneuvers. During running, turns may be substantially constrained by the requirement for body orientation to match movement direction at the end of a turn. A simple mathematical model based on the requirement for rotation to match direction can describe leg forces used by bipeds (humans and ostriches). During running turns, both humans and ostriches control body rotation by generating fore-aft forces. However, whereas humans must generate large braking forces to prevent body over-rotation, ostriches do not. For ostriches, generating the lateral forces necessary to change movement direction results in appropriate body rotation. Although ostriches required smaller braking forces due in part to increased rotational inertia relative to body mass, other movement parameters also played a role. Turning performance resulted from the coordinated behavior of an integrated biomechanical system. Results from preliminary experiments on horizontal-plane stabilization support the hypothesis that controlling body rotation is an important aspect of stable maneuvers. In humans, body orientation relative to movement direction is rapidly stabilized during running turns within the minimum of two steps theoretically required to complete analogous maneuvers. During straight running and cutting turns, humans exhibit spring-mass behavior in the

  16. ERBS orbit ascent utilizing continuous low thrust maneuvers

    NASA Technical Reports Server (NTRS)

    Hoge, S. L.; Oh, I.-H.

    1986-01-01

    The Earth Radiation Budget Satellite (ERBS) is a National Aeronautics and Space Administration (NASA) spacecraft whose purpose is to investigate the components of the earth's radiation budget. The ERBS was deployed in a 57 degree inclined, 352.2 kilometer altitude circular orbit by the NASA Space Transportation System (STS) on October 5, 1984. The spacecraft then ascended to its 603 kilometer, near-circular mission orbit by a series of continuous low-thrust maneuvers. The ERBS was the first free-flyer mission to rely on continuous low thrust to spiral from one circular orbit to another. Careful planning and monitoring of these maneuvers were essential to their successful execution. Errors in the prediction of the propulsion system performance or in burn duration would result in loss of contact with the spacecraft during a maneuver and could result in a premature end to the maneuver and difficulty in computing a definitive orbit.

  17. Automobile maneuvering device

    SciTech Connect

    Ricciardi, R.

    1987-08-18

    An automobile maneuvering device is described which consists of: a chassis comprising transport wheels for permitting movement of the device along the ground, a drive wheel operably rotatably connected to the chassis, and means for rotating the drive wheel, clamp means operably connected to the chassis and spaced from and opposed to the drive wheel, the chassis including means to move the clamp means to engage one portion of an automobile tire with the drive wheel engaged at another portion of the automobile tire, and means to actuate the rotating means, so that with rotation of the drive wheel the automobile tire is rotated and the automobile and device moved along the ground.

  18. Automatic Pilot For Flight-Test Maneuvers

    NASA Technical Reports Server (NTRS)

    Duke, Eugene L.; Jones, Frank P.; Roncoli, Ralph B.

    1992-01-01

    Autopilot replaces pilot during automatic maneuvers. Pilot, based on ground, flies aircraft to required altitude, then turns control over to autopilot. Increases quality of maneuvers significantly beyond that attainable through remote manual control by pilot on ground. Also increases quality of maneuvers because it performs maneuvers faster than pilot could and because it does not have to repeat poorly executed maneuvers.

  19. Aircraft agility maneuvers

    NASA Technical Reports Server (NTRS)

    Cliff, Eugene M.; Thompson, Brian G.

    1992-01-01

    A new dynamic model for aircraft motions is presented. This model can be viewed as intermediate between a point-mass model, in which the body attitude angles are control-like, and a rigid-body model, in which the body-attitude angles evolve according to Newton's Laws. Specifically, consideration is given to the case of symmetric flight, and a model is constructed in which the body roll-rate and the body pitch-rate are the controls. In terms of this body-rate model a minimum-time heading change maneuver is formulated. When the bounds on the body-rates are large the results are similar to the point-mass model in that the model can very quickly change the applied forces and produce an acceleration to turn the vehicle. With finite bounds on these rates, the forces change in a smooth way. This leads to a measurable effect of agility.

  20. Support and maneuvering device

    DOEpatents

    Wood, R.L.

    1987-03-23

    A support and maneuvering device includes an elongated flexible inflatable enclosure having a fixed end and a movable end. The movable end is collapsible toward the fixed end to a contracted position when the enclosure is in a noninflated condition. Upon inflation, the movable end is movable away from the fixed end to an extended position. The movable end includes means for mounting an article such as a solar reflector thereon. The device also includes a plurality of position controlling means disposed about the movable end to effect adjusting movement of portions thereof by predetermined amounts and for controlling an angle at which the article disposed at the movable end is oriented. The plurality of position controlling means limits a suitable number degrees of freedom of the movable end for transmitting a steering motion thereto and for controlling the position thereof. 9 figs.

  1. Support and maneuvering device

    DOEpatents

    Wood, Richard L.

    1988-01-01

    A support and maneuvering device includes an elongated flexible inflatable enclosure having a fixed end and a movable end. The movable end is collapsible toward the fixed end to a contracted position when the enclosure is in a noninflated condition. Upon inflation, the movable end is movable away from the fixed end to an extended position. The movable end includes means for mounting an article such as a solar reflector thereon. The device also includes a plurality of position controlling means disposed about the movable end to effect adjusting movement of portions thereof by predetermined amounts and for controlling an angle at which the article disposed at the movable end is oriented. The plurality of position controlling means limits a suitable number degrees of freedom of the movable end for transmitting a steering motion thereto and for controlling the position thereof.

  2. CHARACTERIZATION OF THE AH RECEPTOR

    EPA Science Inventory

    The rat liver cytosolic receptor protein containing the Ah-receptor protein was purified and studied using a photochemical assembly of 2,3,7,8-TCDD. The unbound receptor protein rapidly lost its capacity to bind 2,3,7,8-TCDD; however, the 2,3,7,8-TCDD bound Ah receptor did not re...

  3. An Independent and Coordinated Criterion for Kinematic Aircraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Narkawicz, Anthony J.; Munoz, Cesar A.; Hagen, George

    2014-01-01

    This paper proposes a mathematical definition of an aircraft-separation criterion for kinematic-based horizontal maneuvers. It has been formally proved that kinematic maneu- vers that satisfy the new criterion are independent and coordinated for repulsiveness, i.e., the distance at closest point of approach increases whether one or both aircraft maneuver according to the criterion. The proposed criterion is currently used in NASA's Airborne Coordinated Resolution and Detection (ACCoRD) set of tools for the design and analysis of separation assurance systems.

  4. A Modified Delphi Study to Define "Ah Ha" Moments in Education Settings

    ERIC Educational Resources Information Center

    Pilcher, Jobeth

    2015-01-01

    Ah ha moments are often mentioned in education literature. These moments are suggested to be a powerful aspect of learning, yet limited research is present regarding this topic. Ah ha learning moments have also not been defined in the education literature, resulting in the likelihood that each educator and learner may have differing definitions.…

  5. Orbital maneuvering end effectors

    NASA Technical Reports Server (NTRS)

    Myers, W. Neill (Inventor); Forbes, John C. (Inventor); Barnes, Wayne L. (Inventor)

    1986-01-01

    This invention relates to an end effector device for grasping and maneuvering objects such as berthing handles of a space telescope. The device includes a V-shaped capture window defined as inclined surfaces in parallel face plates which converge toward a retainer recess in which the handle is retained. A pivotal finger (30) meshes with a pair of pivoted fingers which rotate in counterrotation. The fingers rotate to pull a handle within the capture window into recess where latches lock handle in the recess. To align the capture window, plates may be cocked plus or minus five degrees on base. Drive means is included in the form of a motor coupled with a harmonic drive speed reducer, which provides for slow movement of the fingers at a high torque so that large articles may be handled. Novelty of the invention is believed to reside in the combined intermeshing finger structure, drive means and the harmonic drive speed reducer, which features provide the required maneuverability and strength.

  6. ARTEMIS Maneuvers into Lunar Orbit

    NASA Video Gallery

    This animation visualizes the maneuvers required to move the ARTEMIS spacecraft from their kidney-shaped paths on each side of the moon to orbiting the moon. It took one and a half years, over 90 o...

  7. Noise Prediction for Maneuvering Rotorcraft

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Jones, Henry E.

    2000-01-01

    This paper presents the initial work toward first-principles noise prediction for maneuvering rotors. Both the aeromechanical and acoustics aspects of the maneuver noise problem are discussed. The comprehensive analysis code, CAMRAD 2. was utilized to predict the time-dependent aircraft position and attitude, along - with the rotor blade airloads and motion. The major focus of this effort was the enhancement of the acoustic code WOPWOP necessary to compute the noise from a maneuvering rotorcraft. Full aircraft motion, including arbitrary transient motion, is modeled together with arbitrary rotor blade motions. Noise from a rotorcraft in turning and descending flight is compared to level flight. A substantial increase in the rotor noise is found both for turning flight and during a transient maneuver. Additional enhancements to take advantage of parallel computers and clusters of workstations, in addition to a new compact-chordwise loading formulation, are also described.

  8. STS-133: Rendezvous Pitch Maneuver

    NASA Video Gallery

    At 1:15 p.m. EST Saturday, space shuttle Discovery began the nine-minute Rendezvous Pitch Maneuver, or "backflip." With Commander Steve Lindsey at the helm, Discovery rotated 360 degrees backward t...

  9. STS-134: Rendezvous Pitch Maneuver

    NASA Video Gallery

    On May 18, 2011, space shuttle Endeavour performed the Rendezvous Pitch Maneuver, or "backflip." With Commander Mark Kelly at the helm, Endeavour rotated 360 degrees backward to enable Internationa...

  10. STS-135: Rendezvous Pitch Maneuver

    NASA Video Gallery

    On July 10, 2011, space shuttle Atlantis performed the nine-minute Rendezvous Pitch Maneuver, or “backflip.” With Commander Chris Ferguson at the helm, Atlantis rotated 360 degrees backward to ...

  11. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  12. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  13. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  14. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  15. 14 CFR 25.1507 - Maneuvering speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maneuvering speed. 25.1507 Section 25.1507....1507 Maneuvering speed. The maneuvering speed must be established so that it does not exceed the design maneuvering speed V A determined under § 25.335(c)....

  16. Dynamics of Voluntary Cough Maneuvers

    NASA Astrophysics Data System (ADS)

    Naire, Shailesh

    2008-11-01

    Voluntary cough maneuvers are characterized by transient peak expiratory flows (PEF) exceeding the maximum expiratory flow-volume (MEFV) curve. In some cases, these flows can be well in excess of the MEFV, generally referred to as supramaximal flows. Understanding the flow-structure interaction involved in these maneuvers is the main goal of this work. We present a simple theoretical model for investigating the dynamics of voluntary cough and forced expiratory maneuvers. The core modeling idea is based on a 1-D model of high Reynolds number flow through flexible-walled tubes. The model incorporates key ingredients involved in these maneuvers: the expiratory effort generated by the abdominal and expiratory muscles, the glottis and the flexibility and compliance of the lung airways. Variations in these allow investigation of the expiratory flows generated by a variety of single cough maneuvers. The model successfully reproduces PEF which is shown to depend on the cough generation protocol, the glottis reopening time and the compliance of the airways. The particular highlight is in simulating supramaximal PEF for very compliant tubes. The flow-structure interaction mechanisms behind these are discussed. The wave speed theory of flow limitation is used to characterize the PEF. Existing hypotheses of the origin of PEF, from cough and forced expiration experiments, are also tested using this model.

  17. Software for Autonomous Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Bristow, John; Folta, Dave; Hawkins, Al; Dell, Greg

    2004-01-01

    The AutoCon computer programs facilitate and accelerate the planning and execution of orbital control maneuvers of spacecraft while analyzing and resolving mission constraints. AutoCon-F is executed aboard spacecraft, enabling the spacecraft to plan and execute maneuvers autonomously; AutoCon-G is designed for use on the ground. The AutoCon programs utilize advanced techniques of artificial intelligence, including those of fuzzy logic and natural-language scripting, to resolve multiple conflicting constraints and automatically plan maneuvers. These programs can be used to satisfy requirements for missions that involve orbits around the Earth, the Moon, or any planet, and are especially useful for missions in which there are requirements for frequent maneuvers and for resolution of complex conflicting constraints. During operations, the software targets new trajectories, places and sizes maneuvers, and controls spacecraft burns. AutoCon-G provides a userfriendly graphical interface, and can be used effectively by an analyst with minimal training. AutoCon-F reduces latency and supports multiple-spacecraft and formation-flying missions. The AutoCon architecture supports distributive processing, which can be critical for formation- control missions. AutoCon is completely object-oriented and can easily be enhanced by adding new objects and events. AutoCon-F was flight demonstrated onboard GSFC's EO-1 spacecraft flying in formation with Landsat-7.

  18. Recruitment Maneuvers and PEEP Titration.

    PubMed

    Hess, Dean R

    2015-11-01

    The injurious effects of alveolar overdistention are well accepted, and there is little debate regarding the importance of pressure and volume limitation during mechanical ventilation. The role of recruitment maneuvers is more controversial. Alveolar recruitment is desirable if it can be achieved, but the potential for recruitment is variable among patients with ARDS. A stepwise recruitment maneuver, similar to an incremental PEEP titration, is favored over sustained inflation recruitment maneuvers. Many approaches to PEEP titration have been proposed, and the best method to choose the most appropriate level for an individual patient is unclear. A PEEP level should be selected that balances alveolar recruitment against overdistention. The easiest approach to select PEEP might be according to the severity of the disease: 5-10 cm H2O PEEP in mild ARDS, 10-15 cm H2O PEEP in moderate ARDS, and 15-20 cm H2O PEEP in severe ARDS. Recruitment maneuvers and PEEP should be used within the context of lung protection and not just as a means of improving oxygenation. PMID:26493593

  19. Large Angle Satellite Attitude Maneuvers

    NASA Technical Reports Server (NTRS)

    Cochran, J. E.; Junkins, J. L.

    1975-01-01

    Two methods are proposed for performing large angle reorientation maneuvers. The first method is based upon Euler's rotation theorem; an arbitrary reorientation is ideally accomplished by rotating the spacecraft about a line which is fixed in both the body and in space. This scheme has been found to be best suited for the case in which the initial and desired attitude states have small angular velocities. The second scheme is more general in that a general class of transition trajectories is introduced which, in principle, allows transfer between arbitrary orientation and angular velocity states. The method generates transition maneuvers in which the uncontrolled (free) initial and final states are matched in orientation and angular velocity. The forced transition trajectory is obtained by using a weighted average of the unforced forward integration of the initial state and the unforced backward integration of the desired state. The current effort is centered around practical validation of this second class of maneuvers. Of particular concern is enforcement of given control system constraints and methods for suboptimization by proper selection of maneuver initiation and termination times. Analogous reorientation strategies which force smooth transition in angular momentum and/or rotational energy are under consideration.

  20. Slew maneuvers of large flexible spacecrafts

    NASA Technical Reports Server (NTRS)

    Kakad, Y. P.

    1990-01-01

    The dynamics and control of arbitrary slew maneuvers of a large flexible spacecraft are developed. The dynamics of slew maneuvers are nonlinear and include the coupling between the rigid orbiter and the flexible appendage. A decentralized control scheme is used to perform a large-angle slew maneuver about an arbitrary axis in space and to suppress the vibrations of the flexible appendage during and after the maneuver.

  1. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  2. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  3. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  4. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  5. 33 CFR 84.23 - Maneuvering light.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Maneuvering light. 84.23 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.23 Maneuvering light. Notwithstanding the provisions of § 84.03(f), the maneuvering light described in Rule 34(b) shall be...

  6. Development of Skylab experiment T020 employing a foot controlled maneuvering unit

    NASA Technical Reports Server (NTRS)

    Hewes, D. E.; Glover, K. E.

    1972-01-01

    A review of the plans and preparations is presented for Skylab experiment T020, entitled Foot-Controlled Maneuvering Unit (FCMU). The FCMU is an experimental system intended to explore the use of simple astronaut maneuvering devices in the zero-gravity environment of space. This review also includes discussions of the FCMU concept and experiment hardware systems, as well as supporting experiment definition and development research studies conducted with the aid of zero-gravity simulators.

  7. Cassini Solstice Mission Maneuver Experience: Year Three

    NASA Technical Reports Server (NTRS)

    Wagner, Sean V.; Arrieta, Juan; Hahn, Yungsun; Stumpf, Paul W.; Valerino, Powtawche N.; Wong, Mau C.

    2013-01-01

    The Cassini spacecraft is now in its second Saturn tour extension, the Solstice Mission. By emphasizing propellant preservation over minimizing maneuver cycles, the Cassini Project is meeting the challenge of mission completion in 2017. Since June 2012, 18 of 21 maneuvers were performed to closely maintain the prescribed trajectory, saving downstream propellant. These and other maneuvers during the third year of the Solstice Mission (June 2012 to August 2013) are highlighted in this paper: 31 planned maneuvers targeted to 11 Titan flybys and the last planned Rhea encounter. An assessment of the updated maneuver execution-error models will also be presented.

  8. Cassini Solstice Mission Maneuver Experience: Year Three

    NASA Technical Reports Server (NTRS)

    Wagner, Sean V.; Arrieta, Juan; Hahn, Yungsun; Stumpf, Paul W.; Valerino, Powtawche N.; Wong, Mau C.

    2013-01-01

    The Solstice Mission is the final extension of the Cassini spacecraft s tour of Saturn and its moons. To accommodate an end-of-mission in 2017, the maneuver decision process has been refined. For example, the Cassini Project now prioritizes saving propellant over minimizing maneuver cycles. This paper highlights 30 maneuvers planned from June 2012 through July 2013, targeted to nine Titan flybys and the final Rhea encounter in the mission. Of these maneuvers, 90% were performed to maintain the prescribed trajectory and preserve downstream delta V. Recent operational changes to maneuver executions based on execution-error modeling and analysis are also discussed.

  9. Simulation studies for wells AH-4bis/AH-17 and AH-18, Ahuachapan Geothermal Field

    SciTech Connect

    Monterrosa, Manuel Ernesto

    1996-01-24

    Well AH-4bis, at the Ahuachapan Geothermal Field is planned to be drilled on the same pad as the former AH-4. A simulation study was carried out for two casing dameters 13 5/8 and 9 5/8” in order to estimate its production and to know its economic feasibility. The simulation results indcate a high probability of production in the range of 7 Mwe, equivalent to 120 kg/s total mass flow rate, 1250 kJ/kg at 6 bar-a for the new well AH-4bis. Well AH- 17 is good producer, during 1991 after ten years of production, the well was shut-in due to silica scaling problems. A wellbore simulation was carried out in order to predict the new production conditions after the work-over, mainly to estimate the water flow rate in order to reduce the silica scaling. The results indicate a very low water flow rate. The match between the simulated and measured production curves after the work-over was successful. The well AH-18 is located at the southern part of the actual bore field. CEL is planning to expand the borefield at this area and it is neccessary to estimate the possible production condtions at that zone. The results indicate a high probabilty of production at that area. The power potential is estimated at 3.5 Mwe per well at WHP 6 bar-a and the wells will not require induction.

  10. Manned maneuvering unit latching mechanism

    NASA Technical Reports Server (NTRS)

    Allton, C. S.

    1980-01-01

    The astronaut/Manned Maneuvering Unit interface, which presented a challenging set of requirements for a latching mechanism, is described. A spring loaded cam segment with variable ratio pulley release actuator was developed to meet the requirements. To preclude jamming of the mechanism, special precautions were taken such as spring loaded bearing points and careful selection of materials to resist cold welding. The mechanism successfully passed a number of tests which partially simulated orbital conditions.

  11. LANDSAT-5 orbit adjust maneuver report

    NASA Technical Reports Server (NTRS)

    Hassett, P. J.; Johnson, R. L.

    1984-01-01

    The orbit adjust maneuvers performed to raise the LANDSAT 5 spacecraft to mission altitude, synchronize it with the required groundtrack, and properly phase the spacecraft with LANDSAT-4 to provide an 8 day full Earth coverage cycle are described. Maneuver planning and evaluation procedures, data and analysis results for all maneuvers performed to date, the frozen orbit concept, and the phasing requirement between LANDSAT-4 and LANDSAT-5 are also examined.

  12. Direct lateral maneuvers in hawkmoths.

    PubMed

    Greeter, Jeremy S M; Hedrick, Tyson L

    2016-01-01

    We used videography to investigate direct lateral maneuvers, i.e. 'sideslips', of the hawkmoth Manduca sexta. M. sexta sideslip by rolling their entire body and wings to reorient their net force vector. During sideslip they increase net aerodynamic force by flapping with greater amplitude, (in both wing elevation and sweep), allowing them to continue to support body weight while rolled. To execute the roll maneuver we observed in sideslips, they use an asymmetric wing stroke; increasing the pitch of the roll-contralateral wing pair, while decreasing that of the roll-ipsilateral pair. They also increase the wing sweep amplitude of, and decrease the elevation amplitude of, the contralateral wing pair relative to the ipsilateral pair. The roll maneuver unfolds in a stairstep manner, with orientation changing more during downstroke than upstroke. This is due to smaller upstroke wing pitch angle asymmetries as well as increased upstroke flapping counter-torque from left-right differences in global reference frame wing velocity about the moth's roll axis. Rolls are also opposed by stabilizing aerodynamic moments from lateral motion, such that rightward roll velocity will be opposed by rightward motion. Computational modeling using blade-element approaches confirm the plausibility of a causal linkage between the previously mentioned wing kinematics and roll/sideslip. Model results also predict high degrees of axial and lateral damping. On the time scale of whole and half wing strokes, left-right wing pair asymmetries directly relate to the first, but not second, derivative of roll. Collectively, these results strongly support a roll-based sideslip with a high degree of roll damping in M. sexta. PMID:26740573

  13. Direct lateral maneuvers in hawkmoths

    PubMed Central

    Greeter, Jeremy S. M.; Hedrick, Tyson L.

    2016-01-01

    ABSTRACT We used videography to investigate direct lateral maneuvers, i.e. ‘sideslips’, of the hawkmoth Manduca sexta. M. sexta sideslip by rolling their entire body and wings to reorient their net force vector. During sideslip they increase net aerodynamic force by flapping with greater amplitude, (in both wing elevation and sweep), allowing them to continue to support body weight while rolled. To execute the roll maneuver we observed in sideslips, they use an asymmetric wing stroke; increasing the pitch of the roll-contralateral wing pair, while decreasing that of the roll-ipsilateral pair. They also increase the wing sweep amplitude of, and decrease the elevation amplitude of, the contralateral wing pair relative to the ipsilateral pair. The roll maneuver unfolds in a stairstep manner, with orientation changing more during downstroke than upstroke. This is due to smaller upstroke wing pitch angle asymmetries as well as increased upstroke flapping counter-torque from left-right differences in global reference frame wing velocity about the moth's roll axis. Rolls are also opposed by stabilizing aerodynamic moments from lateral motion, such that rightward roll velocity will be opposed by rightward motion. Computational modeling using blade-element approaches confirm the plausibility of a causal linkage between the previously mentioned wing kinematics and roll/sideslip. Model results also predict high degrees of axial and lateral damping. On the time scale of whole and half wing strokes, left-right wing pair asymmetries directly relate to the first, but not second, derivative of roll. Collectively, these results strongly support a roll-based sideslip with a high degree of roll damping in M. sexta. PMID:26740573

  14. Manned maneuvering unit technology survey

    NASA Technical Reports Server (NTRS)

    Cook, G. V. O. (Editor)

    1975-01-01

    The preliminary design of the manned maneuvering unit (MMU) for the shuttle is investigated, and the current state of the art in certain technology areas that may find application on the operational EVA shuttle MMU is examined. Three broad areas of technology, namely: (1) mechanical energy storage - i.e., the practicality of utilizing the energy storage capability of either a reaction wheel or a control moment gyro, (2) numerical and alphanumerical displays, and (3) recent electronics developments such as microprocessors and integrated injection logic, were covered.

  15. Orbital maneuvers and space rendezvous

    NASA Astrophysics Data System (ADS)

    Butikov, Eugene I.

    2015-12-01

    Several possibilities of launching a space vehicle from the orbital station are considered and compared. Orbital maneuvers discussed in the paper can be useful in designing a trajectory for a specific space mission. The relative motion of orbiting bodies is investigated on examples of spacecraft rendezvous with the space station that stays in a circular orbit around the Earth. An elementary approach is illustrated by an accompanying simulation computer program and supported by a mathematical treatment based on fundamental laws of physics and conservation laws. Material is appropriate for engineers and other personnel involved in space exploration, undergraduate and graduate students studying classical physics and orbital mechanics.

  16. Optical gradient force assist maneuver.

    PubMed

    Artusio-Glimpse, Alexandra B; Wirth, Jacob H; Swartzlander, Grover A

    2016-09-01

    We describe an energy transfer process whereby a moving particle loses (or gains) kinetic energy upon interacting with the moving optical potential of a swept beam of light. This approach is akin to a gravitational assist maneuver for interplanetary satellite propulsion. Special consideration is given to the stopping condition. For analytical convenience, we examine the Rayleigh scattering regime, providing examples at small and large scattering angles. A 5% uncertainty in the initial particle speed and position has negligible effect on the slowing/speeding ability when the beam size is much larger than the particle. PMID:27607993

  17. Optimal Electrodynamic Tether Phasing Maneuvers

    NASA Technical Reports Server (NTRS)

    Bitzer, Matthew S.; Hall, Christopher D.

    2007-01-01

    We study the minimum-time orbit phasing maneuver problem for a constant-current electrodynamic tether (EDT). The EDT is assumed to be a point mass and the electromagnetic forces acting on the tether are always perpendicular to the local magnetic field. After deriving and non-dimensionalizing the equations of motion, the only input parameters become current and the phase angle. Solution examples, including initial Lagrange costates, time of flight, thrust plots, and thrust angle profiles, are given for a wide range of current magnitudes and phase angles. The two-dimensional cases presented use a non-tilted magnetic dipole model, and the solutions are compared to existing literature. We are able to compare similar trajectories for a constant thrust phasing maneuver and we find that the time of flight is longer for the constant thrust case with similar initial thrust values and phase angles. Full three-dimensional solutions, which use a titled magnetic dipole model, are also analyzed for orbits with small inclinations.

  18. Cassini-Huygens maneuver automation for navigation

    NASA Technical Reports Server (NTRS)

    Goodson, Troy; Attiyah, Amy; Buffington, Brent; Hahn, Yungsun; Pojman, Joan; Stavert, Bob; Strange, Nathan; Stumpf, Paul; Wagner, Sean; Wolff, Peter; Wong, Mau

    2006-01-01

    Many times during the Cassini-Huygens mission to Saturn, propulsive maneuvers must be spaced so closely together that there isn't enough time or workforce to execute the maneuver-related software manually, one subsystem at a time. Automation is required. Automating the maneuver design process has involved close cooperation between teams. We present the contribution from the Navigation system. In scope, this includes trajectory propagation and search, generation of ephemerides, general tasks such as email notification and file transfer, and presentation materials. The software has been used to help understand maneuver optimization results, Huygens probe delivery statistics, and Saturn ring-plane crossing geometry. The Maneuver Automation Software (MAS), developed for the Cassini-Huygens program enables frequent maneuvers by handling mundane tasks such as creation of deliverable files, file delivery, generation and transmission of email announcements, generation of presentation material and other supporting documentation. By hand, these tasks took up hours, if not days, of work for each maneuver. Automated, these tasks may be completed in under an hour. During the cruise trajectory the spacing of maneuvers was such that development of a maneuver design could span about a month, involving several other processes in addition to that described, above. Often, about the last five days of this process covered the generation of a final design using an updated orbit-determination estimate. To support the tour trajectory, the orbit determination data cut-off of five days before the maneuver needed to be reduced to approximately one day and the whole maneuver development process needed to be reduced to less than a week..

  19. Dynamic maneuvers with a mobile inverted pendulum

    NASA Astrophysics Data System (ADS)

    Pogue, Edward

    A mobile inverted pendulum (MIP) type robot was constructed to test the feasibility of performing high speed, dynamic maneuvers. Techniques were developed for line following and to achieve high speed motion with a MIP. The results indicate that the speeds necessary for the maneuver can be achieved, and the groundwork is laid for further experimentation.

  20. Method for Studying Helicopter Longitudinal Maneuver Stability

    NASA Technical Reports Server (NTRS)

    Amer, Kenneth B

    1954-01-01

    A theoretical analysis of helicopter maneuver stability is made and the results are compared with experimental results for both a single and a tandem rotor helicopter. Techniques are described for measuring in flight the significant stability derivatives for use with the theory to aid in design studies of means for achieving marginal maneuver stability for a prototype helicopter.

  1. Rolling maneuver load alleviation using active controls

    NASA Technical Reports Server (NTRS)

    Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

    1992-01-01

    Rolling Maneuver Load Alleviation (RMLA) was demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the LaRC Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of .33, .38, and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

  2. Rolling Maneuver Load Alleviation using active controls

    NASA Technical Reports Server (NTRS)

    Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

    1992-01-01

    Rolling Maneuver Load Alleviation (RMLA) has been demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the NASA Langley Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and actuation of the trailing edge inboard control surface pairs to maintain roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of 0.33, .38 and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

  3. Station-Keeping Maneuvers for Geosynchronous Spacecraft

    NASA Technical Reports Server (NTRS)

    Kechichian, J. A.

    1987-01-01

    New strategy saves fuel. Report discusses three existing strategies for maneuvers that maintain apparent position of geosynchronous satellite and present new strategy for satellite subject to daily momentum-wheel dumps. Increases useful lifetime of satellite by reducing frequencies and sizes of maneuvers, reducing rate of fuel consumption.

  4. 46 CFR 109.564 - Maneuvering characteristics.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of each self-propelled unit of 1,600 gross tons...

  5. 46 CFR 109.564 - Maneuvering characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Maneuvering characteristics. 109.564 Section 109.564 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.564 Maneuvering characteristics. (a) The master or person in charge of...

  6. 32 CFR 644.137 - Maneuver agreements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Maneuver agreements. 644.137 Section 644.137 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) REAL PROPERTY REAL ESTATE HANDBOOK Acquisition Acquisition by Leasing § 644.137 Maneuver agreements. Joint...

  7. 32 CFR 644.137 - Maneuver agreements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 4 2011-07-01 2011-07-01 false Maneuver agreements. 644.137 Section 644.137 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) REAL PROPERTY REAL ESTATE HANDBOOK Acquisition Acquisition by Leasing § 644.137 Maneuver agreements. Joint...

  8. Flight Test Maneuvers for Efficient Aerodynamic Modeling

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    2011-01-01

    Novel flight test maneuvers for efficient aerodynamic modeling were developed and demonstrated in flight. Orthogonal optimized multi-sine inputs were applied to aircraft control surfaces to excite aircraft dynamic response in all six degrees of freedom simultaneously while keeping the aircraft close to chosen reference flight conditions. Each maneuver was designed for a specific modeling task that cannot be adequately or efficiently accomplished using conventional flight test maneuvers. All of the new maneuvers were first described and explained, then demonstrated on a subscale jet transport aircraft in flight. Real-time and post-flight modeling results obtained using equation-error parameter estimation in the frequency domain were used to show the effectiveness and efficiency of the new maneuvers, as well as the quality of the aerodynamic models that can be identified from the resultant flight data.

  9. Tactical Maneuvering Using Immunized Sequence Selection

    NASA Technical Reports Server (NTRS)

    Kaneshige, John; KrishnaKumar, K.; Shung, Felix

    2003-01-01

    This paper describes a tactical maneuvering system that uses an artificial immune system based approach for selecting maneuver sequences. This approach combines the problem solving abilities of genetic algorithms with the memory retention characteristics of an immune system. Of significant importance here is the fact that the tactical maneuvering system can make time-critical decisions to accomplish near-term objectives within a dynamic environment. These objectives can be received from a human operator, autonomous executive, or various flight planning specialists. Simulation tests were performed using a high performance military aircraft model. Results demonstrate the potential of using immunized sequence selection in order to accomplish tactical maneuvering objectives ranging from flying to a location while avoiding unforeseen obstacles, to performing relative positioning in support of air combat maneuvering.

  10. Equations of motion for maneuvering flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Meirovitch, L.; Quinn, R. D.

    1987-01-01

    This paper is concerned with the derivation of the equations of motion for maneuvering flexible spacecraft both in orbit and in an earth-based laboratory. The structure is assumed to undergo large rigid-body maneuvers and small elastic deformations. A perturbation approach is presented in which the quantities defining the rigid-body maneuver are regarded as the unperturbed motion and the elastic motions and deviations from the rigid-body motions are regarded as the perturbed motion. The perturbation equations are linear, non-self-adjoint, and with time-dependent coefficients. A maneuver force distribution exciting the least amount of elastic deformation of the spacecraft is developed. Numerical results highlight the vibration caused by rotational maneuvers.

  11. Improved multiframe association for tracking maneuvering targets

    NASA Astrophysics Data System (ADS)

    Habtemariam, Biruk K.; Tharmarasa, R.; Nandakumaran, N.; McDonald, M.; Kirubarajan, T.

    2011-09-01

    Data association is the crucial part of any multitarget tracking algorithm in a scenario with multiple closely spaced targets, low probability of detection and high false alarm rate. Multiframe assignment, which solves the data association problem as a constrained optimization, is one of the widely accepted methods to handle the measurement origin uncertainty. If the targets do not maneuver, then multiframe assignment with one or two frames will be enough to find the correct data association. However, more frames must be considered in the data association for maneuvering targets. Also, a target maneuver might be hard to detect when maneuvering index, which is the function of sampling time, is small. In this paper, we propose an improved multiframe data association with better cost calculation using backward multiple model recursion, which increases the maneuvering index. The effectiveness of the proposed algorithm is demonstrated with simulated data.

  12. Energy Index For Aircraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Chidester, Thomas R. (Inventor); Lynch, Robert E. (Inventor); Lawrence, Robert E. (Inventor); Amidan, Brett G. (Inventor); Ferryman, Thomas A. (Inventor); Drew, Douglas A. (Inventor); Ainsworth, Robert J. (Inventor); Prothero, Gary L. (Inventor); Romanowski, Tomothy P. (Inventor); Bloch, Laurent (Inventor)

    2006-01-01

    Method and system for analyzing, separately or in combination, kinetic energy and potential energy and/or their time derivatives, measured or estimated or computed, for an aircraft in approach phase or in takeoff phase, to determine if the aircraft is or will be put in an anomalous configuration in order to join a stable approach path or takeoff path. A 3 reference value of kinetic energy andor potential energy (or time derivatives thereof) is provided, and a comparison index .for the estimated energy and reference energy is computed and compared with a normal range of index values for a corresponding aircraft maneuver. If the computed energy index lies outside the normal index range, this phase of the aircraft is identified as anomalous, non-normal or potentially unstable.

  13. Manned maneuvering unit: User's guide

    NASA Technical Reports Server (NTRS)

    Lenda, J. A.

    1978-01-01

    The space shuttle will provide an opportunity to extend and enhance the crew's inherent capabilities in orbit by allowing them to operate effectively outside of their spacecraft by means of extravehicular activity. For this role, the shuttle crew will have a new, easier to don and operate space suit with integral life support system, and a self-contained propulsive backpack. The backpack, called the manned maneuvering unit, will allow the crew to operate beyond the confines of the Shuttle cargo bay and fly to any part of their own spacecraft or to nearby free-flying payloads or structure. This independent mobility will be used to support a wide variety of activities including free-space transfer of cargo and personnel, inspection and monitoring of orbital operations, and construction and assembly of large structures in orbit.

  14. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.337 Limit maneuvering load factors. (a) Except where limited by maximum (static)...

  15. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Structure Flight Maneuver and Gust Conditions § 25.337 Limit maneuvering load factors. (a) Except where limited by maximum (static)...

  16. RESULTS FROM THE AHS PESTICIDE EXPOSURE STUDY

    EPA Science Inventory

    The Agricultural Health Study/Pesticide Exposure Study (AHS/PES) measured exposures resulting from agricultural use of 2,4-D and chlorpyrifos for a subset of applicators in the AHS cohort. Through on-farm measurements and observations, data collected in the exposure study will...

  17. CCD Campaign to Observe AH Leonis

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2006-04-01

    Dr. Pamela Gay, Harvard University, has requested optical observations of the RR Lyrae variable star AH Leonis in order to study the Blazhko cycle and other periodicities in this star. Coordinates, finding chart/sequence, observing instructions, and link to AAVSO Variable Star of the Season article on AH Leo (http://www.aavso.org/vstar/vsots/) are provided.

  18. Multi-Maneuver Clohessy-Wiltshire Targeting

    NASA Technical Reports Server (NTRS)

    Dannemiller, David P.

    2011-01-01

    Orbital rendezvous involves execution of a sequence of maneuvers by a chaser vehicle to bring the chaser to a desired state relative to a target vehicle while meeting intermediate and final relative constraints. Intermediate and final relative constraints are necessary to meet a multitude of requirements such as to control approach direction, ensure relative position is adequate for operation of space-to-space communication systems and relative sensors, provide fail-safe trajectory features, and provide contingency hold points. The effect of maneuvers on constraints is often coupled, so the maneuvers must be solved for as a set. For example, maneuvers that affect orbital energy change both the chaser's height and downrange position relative to the target vehicle. Rendezvous designers use experience and rules-of-thumb to design a sequence of maneuvers and constraints. A non-iterative method is presented for targeting a rendezvous scenario that includes a sequence of maneuvers and relative constraints. This method is referred to as Multi-Maneuver Clohessy-Wiltshire Targeting (MM_CW_TGT). When a single maneuver is targeted to a single relative position, the classic CW targeting solution is obtained. The MM_CW_TGT method involves manipulation of the CW state transition matrix to form a linear system. As a starting point for forming the algorithm, the effects of a series of impulsive maneuvers on the state are derived. Simple and moderately complex examples are used to demonstrate the pattern of the resulting linear system. The general form of the pattern results in an algorithm for formation of the linear system. The resulting linear system relates the effect of maneuver components and initial conditions on relative constraints specified by the rendezvous designer. Solution of the linear system includes the straight-forward inverse of a square matrix. Inversion of the square matrix is assured if the designer poses a controllable scenario - a scenario where the the

  19. TOPEX/Poseidon orbit acquisition maneuver design

    NASA Technical Reports Server (NTRS)

    Bhat, Ramachandra S.

    1992-01-01

    The current baseline injection orbit for the jointly sponsored NASA/CNES TOPEX/Poseidon mission is near-circular, approximately 30 km below the desired operational orbit altitude and at the operational orbit inclination. A baseline maneuver sequence to retarget from this injection orbit to the desired operational orbit has been designed based upon the expected worst-case 3-sigma injection and maneuver execution errors. The sequence requires seven maneuvers, including an initial calibration burn, and achieves the operational orbit with the desired ground track pattern in 30 days. A delay sensitivity analysis has been conducted to estimate the allowable operational delay for each maneuver without increasing the total orbit acquisition period. The baseline sequence provides back-ups for a one-revolution delay for each maneuver and one-day delay for most maneuvers. It is also shown that a higher injection orbit allows the maneuver sequence to achieve the operational orbit in 26 days under a worst-case scenario.

  20. Optimal Propellant Maneuver Flight Demonstrations on ISS

    NASA Technical Reports Server (NTRS)

    Bhatt, Sagar; Bedrossian, Nazareth; Longacre, Kenneth; Nguyen, Louis

    2013-01-01

    In this paper, first ever flight demonstrations of Optimal Propellant Maneuver (OPM), a method of propulsive rotational state transition for spacecraft controlled using thrusters, is presented for the International Space Station (ISS). On August 1, 2012, two ISS reorientations of about 180deg each were performed using OPMs. These maneuvers were in preparation for the same-day launch and rendezvous of a Progress vehicle, also a first for ISS visiting vehicles. The first maneuver used 9.7 kg of propellant, whereas the second used 10.2 kg. Identical maneuvers performed without using OPMs would have used approximately 151.1kg and 150.9kg respectively. The OPM method is to use a pre-planned attitude command trajectory to accomplish a rotational state transition. The trajectory is designed to take advantage of the complete nonlinear system dynamics. The trajectory choice directly influences the cost of the maneuver, in this case, propellant. For example, while an eigenaxis maneuver is kinematically the shortest path between two orientations, following that path requires overcoming the nonlinear system dynamics, thereby increasing the cost of the maneuver. The eigenaxis path is used for ISS maneuvers using thrusters. By considering a longer angular path, the path dependence of the system dynamics can be exploited to reduce the cost. The benefits of OPM for the ISS include not only reduced lifetime propellant use, but also reduced loads, erosion, and contamination from thrusters due to fewer firings. Another advantage of the OPM is that it does not require ISS flight software modifications since it is a set of commands tailored to the specific attitude control architecture. The OPM takes advantage of the existing ISS control system architecture for propulsive rotation called USTO control mode1. USTO was originally developed to provide ISS Orbiter stack attitude control capability for a contingency tile-repair scenario, where the Orbiter is maneuvered using its robotic

  1. Development Of Maneuvering Autopilot For Flight Tests

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Walker, R. A.

    1992-01-01

    Report describes recent efforts to develop automatic control system operating under supervision of pilot and making airplane follow prescribed trajectories during flight tests. Report represents additional progress on this project. Gives background information on technology of control of test-flight trajectories; presents mathematical models of airframe, engine and command-augmentation system; focuses on mathematical modeling of maneuvers; addresses design of autopilots for maneuvers; discusses numerical simulation and evaluation of results of simulation of eight maneuvers under control of simulated autopilot; and presents summary and discussion of future work.

  2. Cassini Solstice Mission Maneuver Experience: Year One

    NASA Technical Reports Server (NTRS)

    Wagner, Sean V.; Arrieta, Juan; Ballard, Christopher G.; Hahn, Yungsun; Stumpf, Paul W.; Valerino, Powtawche N.

    2011-01-01

    The Cassini-Huygens spacecraft began its four-year Prime Mission to study Saturn's system in July 2004. Two tour extensions followed: a two-year Equinox Mission beginning in July 2008 and a seven-year Solstice Mission starting in September 2010. This paper highlights Cassini maneuver activities from June 2010 through June 2011, covering the transition from the Equinox to Solstice Mission. This interval included 38 scheduled maneuvers, nine targeted Titan flybys, three targeted Enceladus flybys, and one close Rhea flyby. In addition, beyond the demanding nominal navigation schedule, numerous unforeseen challenges further complicated maneuver operations. These challenges will be discussed in detail.

  3. Maneuvering and vibration control of flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Meirovitch, L.; Quinn, R. D.

    1987-01-01

    This paper is concerned with the problem of slewing a large structure in space and suppressing any vibration at the same time. The structure is assumed to undergo large rigid-body motions and small elastic deformations. A perturbation method permits a maneuver strategy independent of the vibration control. Optimal control and pole placement techniques, formulated to include first-order actuator dynamics, are used to suppress the vibration during maneuver. The theory is illustrated by simultaneous maneuvering and vibration control of the Spacecraft Control Laboratory Experiment (SCOLE) model in a space environment.

  4. Rapid multi-flexible-body maneuvering experiments

    NASA Technical Reports Server (NTRS)

    Juang, Jer-Nan

    1988-01-01

    Progress at the NASA Langley Research Center in the area of rapid multiple-flexible-body maneuvering experiments is described. The experiments are designed to verify theoretical analyses using control theory for the control of flexible structures. The objective of the maneuvering experiments is to demonstrate slewing of flexible structures in multiple axes while simultaneously suppressing vibration to have acceptable motion at the end of the maneuver. The status of some research activities oriented primarily to the experimental methods for control of flexible structures is presented.

  5. Helicopter stability during aggressive maneuvers

    NASA Astrophysics Data System (ADS)

    Mohan, Ranjith

    The dissertation investigates helicopter trim and stability during level bank-angle and diving bank-angle turns. The level turn is moderate in that sufficient power is available to maintain level maneuver, and the diving turn is severe where the power deficit is overcome by the kinetic energy of descent. The investigation basically represents design conditions where the peak loading goes well beyond the steady thrust limit and the rotor experiences appreciable stall. The major objectives are: (1) to assess the sensitivity of the trim and stability predictions to the approximations in modeling stall, (2) to correlate the trim predictions with the UH-60A flight test data, and (3) to demonstrate the feasibility of routinely using the exact fast-Floquet periodic eigenvector method for mode identification in the stability analysis. The UH-60A modeling and analysis are performed using the comprehensive code RCAS (Army's Rotorcraft Comprehensive Analysis System). The trim and damping predictions are based on quasisteady stall, ONERA-Edlin (Equations Differentielles Lineaires) and Leishman-Beddoes dynamic stall models. From the correlation with the test data, the strengths and weaknesses of the trim predictions are presented.

  6. Canadarm2 Maneuvers Quest Airlock

    NASA Technical Reports Server (NTRS)

    2001-01-01

    At the control of Expedition Two Flight Engineer Susan B. Helms, the newly-installed Canadian-built Canadarm2, Space Station Remote Manipulator System (SSRMS) maneuvers the Quest Airlock into the proper position to be mated onto the starboard side of the Unity Node I during the first of three extravehicular activities (EVA) of the STS-104 mission. The Quest Airlock makes it easier to perform space walks, and allows both Russian and American spacesuits to be worn when the Shuttle is not docked with the International Space Station (ISS). American suits will not fit through Russion airlocks at the Station. The Boeing Company, the space station prime contractor, built the 6.5-ton (5.8 metric ton) airlock and several other key components at the Marshall Space Flight Center (MSFC), in the same building where the Saturn V rocket was built. Installation activities were supported by the development team from the Payload Operations Control Center (POCC) located at the MSFC and the Mission Control Center at NASA's Johnson Space Flight Center in Houston, Texas.

  7. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Balancing Surfaces § 23.423 Maneuvering loads. Each horizontal surface and its supporting structure, and the...-down pitching conditions is the sum of the balancing loads at V and the specified value of the...

  8. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Balancing Surfaces § 23.423 Maneuvering loads. Each horizontal surface and its supporting structure, and the...-down pitching conditions is the sum of the balancing loads at V and the specified value of the...

  9. 14 CFR 29.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factor. 29.337... Limit maneuvering load factor. The rotorcraft must be designed for— (a) A limit maneuvering load factor... load factor not less than 2.0 and any negative limit maneuvering load factor of not less than −0.5...

  10. Optimization of satellite constellation reconfiguration maneuvers

    NASA Astrophysics Data System (ADS)

    Appel, Leonid; Guelman, Moshe; Mishne, David

    2014-06-01

    Constellation satellites are required to perform orbital transfer maneuvers. Orbital transfer maneuvers, as opposed to orbital correction maneuvers, are seldom performed but require a substantial amount of propellant for each maneuver. The maneuvers are performed in order to obtain the desired constellation configuration that satisfies the coverage requirements. In most cases, the single-satellite position is immaterial; rather the relative position between constellation multiple-satellites is to be controlled. This work deals with the solution to the coupled optimization problem of multiple-satellite orbital transfer. The studied problem involves a coupled formulation of the terminal conditions of the satellites. The solution was achieved using functional optimization techniques by a combined algorithm. The combined algorithm is based on the First Order Gradient and Neighboring-Extremals Algorithms. An orbital transfer optimization tool was developed. This software has the ability to consider multiple satellites with coupled terminal conditions. A solution to the multiple-satellite orbital transfer optimization problem is presented. A comparison of this solution to the uncoupled case is presented in order to review the benefits of using this approach. It is concluded that the coupled transfer maneuver solution approach is more computationally efficient and more accurate. Numerical solutions for a number of representative cases are presented.

  11. AhR signalling and dioxin toxicity.

    PubMed

    Sorg, Olivier

    2014-10-15

    Dioxins are a family of molecules associated to several industrial accidents such as Ludwigshafen in 1953 or Seveso in 1976, to the Agent Orange used during the war of Vietnam, and more recently to the poisoning of the former president of Ukraine, Victor Yushchenko. These persistent organic pollutants are by-products of industrial activity and bind to an intracellular receptor, AhR, with a high potency. In humans, exposure to dioxins, in particular 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces a cutaneous syndrome known as chloracne, consisting in the development of many small skin lesions (hamartoma), lasting for 2-5 years. Although TCDD has been classified by the WHO as a human carcinogen, its carcinogenic potential to humans is not clearly demonstrated. It was first believed that AhR activation accounted for most, if not all, biological properties of dioxins. However, certain AhR agonists found in vegetables do not induce chloracne, and other chemicals, in particular certain therapeutic agents, may induce a chloracne-like syndrome without activating AhR. It is time to rethink the mechanism of dioxin toxicity and analyse in more details the biological events following exposure to these compounds and other AhR agonists, some of which have a very different chemical structure than TCDD. In particular various food-containing AhR agonists are non-toxic and may on the contrary have beneficial properties to human health. PMID:24239782

  12. Improved Maneuver Reconstructions for the GRAIL Orbiters

    NASA Technical Reports Server (NTRS)

    Keck, Mason; You, Tung-Han; Antreasian, Peter

    2012-01-01

    Maneuver reconstructions for the Gravity Recovery and Interior Laboratory (GRAIL) A and B lunar orbiters were improved through updates to the orbit determination filter and dynamic models. Consistent reconstructions of the 27 GRAIL A and B maneuvers from the Trans-Lunar Cruise phase in the fall of 2011 through the Transition to Science Formation phase in February 2012 were performed. Standard methods of orbit determination were applied incorporating the latest dynamic models and filter strategies developed by the GRAIL Navigation and Science Teams, including a high resolution, 420 x 420 degree and order lunar spherical harmonic gravity field model. For Trans-Lunar Cruise for GRAIL-A (TLC-A), all maneuvers executed with delta V errors below 5.50 +/- 0.50 mm/s and pointing errors below 0.25 degrees. GRAIL-A lunar orbit maneuvers had delta V errors below 30.0 mm/s and pointing errors below 0.51 degrees. For TLC-B, all maneuvers executed with delta V errors below 8.60 +/- 1.41 mm/s and pointing errors below 0.300 degrees. GRAIL-B maneuvers in lunar orbit executed with maximum delta V errors of 25.0 mm/s and pointing error of 0.43 degrees. These maneuver reconstructions will enable the GRAIL Navigation Team to better characterize the main engine performance of each spacecraft. This will help the Navigation Team to navigate low (greater than 8 km) altitude orbits during the extended mission phase in the fall of 2012.

  13. Cassini's Maneuver Automation Software (MAS) Process: How to Successfully Command 200 Navigation Maneuvers

    NASA Technical Reports Server (NTRS)

    Yang, Genevie Velarde; Mohr, David; Kirby, Charles E.

    2008-01-01

    To keep Cassini on its complex trajectory, more than 200 orbit trim maneuvers (OTMs) have been planned from July 2004 to July 2010. With only a few days between many of these OTMs, the operations process of planning and executing the necessary commands had to be automated. The resulting Maneuver Automation Software (MAS) process minimizes the workforce required for, and maximizes the efficiency of, the maneuver design and uplink activities. The MAS process is a well-organized and logically constructed interface between Cassini's Navigation (NAV), Spacecraft Operations (SCO), and Ground Software teams. Upon delivery of an orbit determination (OD) from NAV, the MAS process can generate a maneuver design and all related uplink and verification products within 30 minutes. To date, all 112 OTMs executed by the Cassini spacecraft have been successful. MAS was even used to successfully design and execute a maneuver while the spacecraft was in safe mode.

  14. Life testing of secondary silver-zinc cells for the orbiting maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Brewer, Jeffrey C.; Doreswamy, Rajiv; Jackson, Lorna G.

    1990-01-01

    Over the past 5 years, extensive testing has been performed at the Marshall Space Flight Center (MSFC) on a variety of secondary (rechargeable) silver-zinc (Ag-Zn) cells for the Orbital Maneuvering Vehicle (OMV). The first tests performed were to determine the feasibility of using such a cell in a long-life (18-month), low-Earth-orbit (LEO) application. Results from these tests were promising, so testing continued with a 250-Ah cell that was specifically designed for this type of application. Once again, results from the tests were promising. Following a review of the data from these previous tests, slight modifications to the 250-Ah design were necessary to alleviate problem areas. Currently, MSFC is testing a 350-Ah design that has incorporated these changes and is the baseline design for the OMV. This test began in mid-November, 1989, and will be complete in the spring of 1991, barring any substantial offline time. A report is presented on the preliminary results from the first few months of this test and they are compared to results obtained in previous tests done at MFSC.

  15. Close approach maneuvers around an oblate planet

    NASA Astrophysics Data System (ADS)

    Oliveira, G. M. C.; Prado, A. F. B. A.; Sanchez, D. M.

    2015-10-01

    There are many applications of the close approach maneuvers in astronautics, and several missions used this technique in the last decades. In the present work, those close approach maneuvers are revisited, but now considering that the spacecraft passes around an oblate planet. This fact changes the distribution of mass of the planet, increasing the mass in the region of the equator, so increasing the gravitational forces in the equatorial plane. Since the present study is limited to planar trajectories, there is an increase in the variation of energy given by the maneuver. The planet Jupiter is used as the body for the close approach, but the value of J2 is varied in a large range to simulate situations of other celestial bodies that have larger oblateness, but the same mass ratio. This is particularly true in recent discovered exoplanets, and this first study can help the study of the dynamics around those bodies.

  16. Cassini Maneuver Experience: Ending the Equinox Mission

    NASA Technical Reports Server (NTRS)

    Ballard, Christopher G.; Arrieta, Juan; Hahn, Yungsun; Stumpf, Paul W.; Wagner, Sean V.; Williams, Powtawche N.

    2010-01-01

    The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year interplanetary cruise, it entered a Saturnian orbit for a four-year Prime Mission in 2004 and began a two-year Equinox Mission in 2008. It has been approved for another seven-year mission, the Solstice Mission, starting in October 2010. This paper highlights significant maneuver activities performed from July 2009 to June 2010. We present results for the 45 maneuvers during this time. The successful navigation of the Cassini orbiter can be attributed in part to the accurate maneuver performance, which has greatly exceeded pre-launch expectations.

  17. Maneuver Design Using Relative Orbital Elements

    NASA Astrophysics Data System (ADS)

    Spencer, David A.; Lovell, Thomas A.

    2015-12-01

    Relative orbital elements provide a geometric interpretation of the motion of a deputy spacecraft about a chief spacecraft. The formulation yields an intuitive understanding of how the relative motion evolves with time, and by incorporating velocity changes in the local-vertical, local-horizontal component directions, the change in relative motion due to impulsive maneuvers can be evaluated. This paper utilizes a relative orbital element formulation that characterizes relative motion where the chief spacecraft is assumed to be in a circular orbit. Expressions are developed for changes to the relative orbital elements as a function of the impulsive maneuver components in each coordinate direction. A general maneuver strategy is developed for targeting a set of relative orbital elements, and this strategy is applied to scenarios that are relevant for close proximity operations, including establishing a stationary relative orbit, natural motion circumnavigation, and station-keeping in a leading or trailing orbit.

  18. Maneuvering and control of flexible space robots

    NASA Technical Reports Server (NTRS)

    Meirovitch, Leonard; Lim, Seungchul

    1994-01-01

    This paper is concerned with a flexible space robot capable of maneuvering payloads. The robot is assumed to consist of two hinge-connected flexible arms and a rigid end-effector holding a payload; the robot is mounted on a rigid platform floating in space. The equations of motion are nonlinear and of high order. Based on the assumption that the maneuvering motions are one order of magnitude larger than the elastic vibrations, a perturbation approach permits design of controls for the two types of motion separately. The rigid-body maneuvering is carried out open loop, but the elastic motions are controlled closed loop, by means of discrete-time linear quadratic regulator theory with prescribed degree of stability. A numerical example demonstrates the approach. In the example, the controls derived by the perturbation approach are applied to the original nonlinear system and errors are found to be relatively small.

  19. Cassini Solstice Mission Maneuver Experience: Year Two

    NASA Technical Reports Server (NTRS)

    Arrieta, Juan; Ballard, Christopher G.; Hahn, Yungsun

    2012-01-01

    The Cassini Spacecraft was launched in October 1997 on a mission to observe Saturn and its moons; it entered orbit around Saturn in July 2004 for a nominal four-year Prime Mission, later augmented by two extensions: the Equinox Mission, from July 2008 through September 2010, and the Solstice Mission, from October 2010 through September 2017. This paper provides an overview of the maneuver activities from August 2011 through June 2012 which include the design of 38 Orbit Trim Maneuvers--OTM-288 through OTM-326-- for attaining 14 natural satellite encounters: seven with Titan, six with Enceladus, and one with Dione.

  20. Laparoscopic Pringle maneuver: how we do it?

    PubMed Central

    Lhuaire, Martin; Memeo, Riccardo; Pessaux, Patrick; Kianmanesh, Reza; Sommacale, Daniele

    2016-01-01

    Laparoscopic liver resection (LLR) is technically possible with new devices which allow a relatively bloodless liver parenchymal transection. Despite, the main concern remains intraoperative hemorrhage. Currently, perioperative excessive blood loss during LLR is difficult to control with necessity of laparotomy conversion. Moreover, major blood loss requires transfusion and increases postoperative morbidity and mortality. When in-flow is limited by the hepatic pedicle clamping, it reduces intraoperative blood loss. The Pringle maneuver, first described in 1908, is the simplest method of inflow occlusion and currently can be achieved during LLR. The purpose of this note was to describe two different modalities of Pringle maneuver used by two different teams during LLR. PMID:27500146

  1. Mars Science Laboratory Cruise Propulsion Maneuvering Operations

    NASA Technical Reports Server (NTRS)

    Baker, Raymond S.; Mizukami, Masahi; Barber, Todd J.

    2013-01-01

    Mars Science Laboratory "Curiosity" is NASA's most recent mission to Mars, launched in November 2011, and landed in August 2012. It is a subcompact car-sized nuclear powered rover designed for a long duration mission, with an extensive suite of science instruments. Entry, descent and landing used a unique "skycrane" concept. This report describes the propulsive maneuvering operations during cruise from Earth to Mars, to control attitudes and to target the vehicle for entry. The propulsion subsystem, mission operations, and flight performance are discussed. All trajectory control maneuvers were well within accuracy requirements, and all turns and spin corrections were nominal.

  2. Laparoscopic Pringle maneuver: how we do it?

    PubMed

    Piardi, Tullio; Lhuaire, Martin; Memeo, Riccardo; Pessaux, Patrick; Kianmanesh, Reza; Sommacale, Daniele

    2016-08-01

    Laparoscopic liver resection (LLR) is technically possible with new devices which allow a relatively bloodless liver parenchymal transection. Despite, the main concern remains intraoperative hemorrhage. Currently, perioperative excessive blood loss during LLR is difficult to control with necessity of laparotomy conversion. Moreover, major blood loss requires transfusion and increases postoperative morbidity and mortality. When in-flow is limited by the hepatic pedicle clamping, it reduces intraoperative blood loss. The Pringle maneuver, first described in 1908, is the simplest method of inflow occlusion and currently can be achieved during LLR. The purpose of this note was to describe two different modalities of Pringle maneuver used by two different teams during LLR. PMID:27500146

  3. A torque balance control moment gyroscope assembly for astronaut maneuvering

    NASA Technical Reports Server (NTRS)

    Cunningham, D. C.; Driskill, G. W.

    1972-01-01

    A control moment gyroscope assembly is described for use in an astronaut maneuvering research vehicle. This vehicle (backpack) will be used by astronauts inside the orbiting Skylab for evaluation of various maneuvering systems.

  4. A New Maneuver for Escape Trajectories

    NASA Technical Reports Server (NTRS)

    Adams, Robert B.

    2008-01-01

    This presentation put forth a new maneuver for escape trajectories and specifically sought to find an analytical approximation for medium thrust trajectories. In most low thrust derivations the idea is that escape velocity is best achieved by accelerating along the velocity vector. The reason for this is that change in specific orbital energy is a function of velocity and acceleration. However, Levin (1952) suggested that while this is a locally optimal solution it might not be a globally optimal one. Turning acceleration inward would drop periapse giving a higher velocity later in the trajectory. Acceleration at that point would be dotted against a higher magnitude V giving a greater rate of change of mechanical energy. The author then hypothesized that decelerating from the initial orbit and then accelerating at periapse would not lead to a gain in greater specific orbital energy--however, the hypothesis was incorrect. After considerable derivation it was determined that this new maneuver outperforms a direct burn when the overall DeltaV budget exceeds the initial orbital velocity (the author has termed this the Heinlein maneuver). The author provides a physical explanation for this maneuver and presents optimization analyses.

  5. 46 CFR 131.990 - Maneuvering characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS... condition of loading, assuming the following: (1) Calm weather—wind 10 knots or less, calm sea. (2) No... maneuvering information is based, are varied: (i) Calm weather—wind 10 knots or less, calm sea. (ii)...

  6. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    .../sec2) Nose-up pitching 1.0 +39nm÷V×(nm−1.5) Nose-down pitching nm −39nm÷V×(nm−1.5) where— (1) nm... exceeding the limit maneuvering load factor. The total horizontal surface load for both nose-up and...

  7. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .../sec2) Nose-up pitching 1.0 +39nm÷V×(nm−1.5) Nose-down pitching nm −39nm÷V×(nm−1.5) where— (1) nm... exceeding the limit maneuvering load factor. The total horizontal surface load for both nose-up and...

  8. 14 CFR 23.423 - Maneuvering loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .../sec2) Nose-up pitching 1.0 +39nm÷V×(nm−1.5) Nose-down pitching nm −39nm÷V×(nm−1.5) where— (1) nm... exceeding the limit maneuvering load factor. The total horizontal surface load for both nose-up and...

  9. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  10. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  11. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  12. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 23 Highways 1 2013-04-01 2013-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  13. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  14. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 23 Highways 1 2012-04-01 2012-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  15. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 23 Highways 1 2014-04-01 2014-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  16. 23 CFR 660.517 - Maneuver area roads.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Maneuver area roads. 660.517 Section 660.517 Highways... PROGRAMS (DIRECT FEDERAL) Defense Access Roads § 660.517 Maneuver area roads. (a) Claims by a highway agency for costs incurred to restore, to their former condition, roads damaged by maneuvers involving...

  17. 14 CFR 23.155 - Elevator control force in maneuvers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Elevator control force in maneuvers. 23.155... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force... curve of stick force versus maneuvering load factor with increasing load factor....

  18. 14 CFR 23.155 - Elevator control force in maneuvers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Elevator control force in maneuvers. 23.155... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force... curve of stick force versus maneuvering load factor with increasing load factor....

  19. 14 CFR 23.155 - Elevator control force in maneuvers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Elevator control force in maneuvers. 23.155... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force... curve of stick force versus maneuvering load factor with increasing load factor....

  20. 14 CFR 23.155 - Elevator control force in maneuvers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Elevator control force in maneuvers. 23.155... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force... curve of stick force versus maneuvering load factor with increasing load factor....

  1. 14 CFR 23.155 - Elevator control force in maneuvers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Elevator control force in maneuvers. 23.155... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control force... curve of stick force versus maneuvering load factor with increasing load factor....

  2. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  3. 14 CFR 23.1507 - Operating maneuvering speed.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Operating maneuvering speed. 23.1507... Limitations and Information § 23.1507 Operating maneuvering speed. The maximum operating maneuvering speed, VO, must be established as an operating limitation. VO is a selected speed that is not greater than...

  4. Novel vagal maneuver technique for termination of supraventricular tachycardias.

    PubMed

    Un, Haluk; Dogan, Mehmet; Uz, Omer; Isilak, Zafer; Uzun, Mehmet

    2016-01-01

    Hemodynamically unstable patients with supraventricular tachycardias (SVTs) should be treated with electrical cardioversion. If the patient is stable, acute termination of tachycardia can be achieved by vagal maneuvers or medical therapy. The Valsalva maneuver, carotid massage, and ice to the face are the most common vagal maneuvers. In our experience with patients, we observed that vagal stimulation increases with lying backward. Our suggested maneuver is based on quickly lying backward, from a seated position. Then, a short and powerful vagal stimulation occurs. Thus, SVT episodes can be terminated. Here we present our experience of a new maneuver for terminating SVT, with cases. PMID:26209466

  5. Sonic boom focal zones due to tactical aircraft maneuvers

    NASA Astrophysics Data System (ADS)

    Plotkin, Kenneth J.

    1990-10-01

    A study has been conducted of the focal zone 'superbooms' associated with tactical maneuvers of military supersonic aircraft. Focal zone footprints were computed for 21 tactical maneuvers: two for the SR-71 and 19 for fighters engaged in air combat maneuver (ACM) training. These footprints provide quantitative results which may be used for environmental planning. A key finding of this study is that focus factors and footprint areas for high-g fighter maneuvers are substantially smaller than those for gentle maneuvers associated with larger aircraft.

  6. Simple computations for near-optimum ascent and abort maneuver targets and deorbit ignition time

    NASA Technical Reports Server (NTRS)

    Mchenry, R. L.

    1980-01-01

    Closed-form solutions are presented for a two-burn orbit insertion, AOA, and ATO maneuver targets, and for time of ignition of a one-burn deorbit. Based on the assumption that the orbits involved deviate only to the first order about a reference circular orbit, these solutions are nearly fuel-minimum. They are expressed in terms of linear terminal velocity constraint shuttle guidance targets and, thus, are readily applicable to both ground and onboard software use. In addition to potential application to real-time targeting, the equations may be used as a mission design aid in preliminary definition of target loads and definition of abort mode boundaries.

  7. Plan, formulate, and discuss a NASTRAN finite element model of the AH-64A helicopter airframe

    NASA Technical Reports Server (NTRS)

    Christ, Richard A.; Ferg, Douglas A.; Kilroy, Kevin A.; Toossi, Mostafa; Weisenburger, Richard K.

    1990-01-01

    A discussion of modeling plan objectives, followed by a description of the AH-64A aircraft including all general features, major components, and primary and structure definitions are presented. Following the aircraft description, a discussion of the modeling guidelines and model checkout procedure are provided. The NASTRAN finite element analysis is set up to be suitable to predict both static internal loads and vibrations. Finally, the results, schedule, and planned versus actual manhours for this work are presented.

  8. The efficacy of the "BURP" maneuver during a difficult laryngoscopy.

    PubMed

    Takahata, O; Kubota, M; Mamiya, K; Akama, Y; Nozaka, T; Matsumoto, H; Ogawa, H

    1997-02-01

    The displacement of the larynx in the three specific directions (a) posteriorly against the cervical vertebrae, (b) superiorly as possible, and (c) slightly laterally to the right have been reported and named the "BURP" maneuver. We evaluated the efficacy of the BURP maneuver in improving visualization of the larynx. Six hundred thirty patients without obvious malformation of the head and neck participated in this study. We divided the degree of visualization of the larynx using laryngoscopy into five grades and compared the visualization of the larynx using the BURP maneuver with that of laryngoscopy with and without simple laryngeal pressure ("Back"). The maneuver of Back and BURP significantly improved the laryngoscopic visualization from initial inspection. The BURP maneuver also significantly improved the visualization compared with the Back maneuver. We concluded that the BURP maneuver improved the visualization of the larynx more easily than simple back pressure on the larynx. PMID:9024040

  9. Dynamic Tow Maneuver Orbital Launch Technique

    NASA Technical Reports Server (NTRS)

    Rutan, Elbert L. (Inventor)

    2014-01-01

    An orbital launch system and its method of operation use a maneuver to improve the launch condition of a booster rocket and payload. A towed launch aircraft, to which the booster rocket is mounted, is towed to a predetermined elevation and airspeed. The towed launch aircraft begins the maneuver by increasing its lift, thereby increasing the flight path angle, which increases the tension on the towline connecting the towed launch aircraft to a towing aircraft. The increased tension accelerates the towed launch aircraft and booster rocket, while decreasing the speed (and thus the kinetic energy) of the towing aircraft, while increasing kinetic energy of the towed launch aircraft and booster rocket by transferring energy from the towing aircraft. The potential energy of the towed launch aircraft and booster rocket is also increased, due to the increased lift. The booster rocket is released and ignited, completing the launch.

  10. Rendezvous radar for the orbital maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Locke, John W.; Olds, Keith A.; Quaid, Thomas

    1991-01-01

    The Rendezvous Radar Set (RRS) was designed at Motorola's Strategic Electronics Division in Chandler, Arizona, to be a key subsystem aboard NASA's Orbital Maneuvering Vehicle (OMV). The unmanned OMV, which was under development at TRW's Federal Systems Division in Redondo Beach, California, was designed to supplement the Shuttle's satellite delivery, retrieval, and maneuvering activities. The RRS was to be used to locate and then provide the OMV with vectoring information to the target satellite (or Shuttle or Space Station) to aid the OMV in making a minimum fuel consumption approach and rendezvous. The OMV development program was halted by NASA in 1990 just as parts were being ordered for the RRS engineering model. The paper presented describes the RRS design and then discusses new technologies, either under development or planned for development at Motorola, that can be applied to radar or alternative sensor solutions for the Automated Rendezvous and Capture problem.

  11. Hydrodynamics of maneuvering bodies: LDRD final report

    SciTech Connect

    Kempka, S.N.; Strickland, J.H.

    1994-01-01

    The objective of the ``Hydrodynamics of Maneuvering Bodies`` LDRD project was to develop a Lagrangian, vorticity-based numerical simulation of the fluid dynamics associated with a maneuvering submarine. Three major tasks were completed. First, a vortex model to simulate the wake behind a maneuvering submarine was completed, assuming the flow to be inviscid and of constant density. Several simulations were performed for a dive maneuver, each requiring less than 20 cpu seconds on a workstation. The technical details of the model and the simulations are described in a separate document, but are reviewed herein. Second, a gridless method to simulate diffusion processes was developed that has significant advantages over previous Lagrangian diffusion models. In this model, viscous diffusion of vorticity is represented by moving vortices at a diffusion velocity, and expanding the vortices as specified by the kinematics for a compressible velocity field. This work has also been documented previously, and is only reviewed herein. The third major task completed was the development of a vortex model to describe inviscid internal wave phenomena, and is the focus of this document. Internal wave phenomena in the stratified ocean can affect an evolving wake, and thus must be considered for naval applications. The vortex model for internal wave phenomena includes a new formulation for the generation of vorticity due to fluid density variations, and a vortex adoption algorithm that allows solutions to be carried to much longer times than previous investigations. Since many practical problems require long-time solutions, this new adoption algorithm is a significant step toward making vortex methods applicable to practical problems. Several simulations are described and compared with previous results to validate and show the advantages of the new model. An overview of this project is also included.

  12. Identifying tacit strategies in aircraft maneuvers

    NASA Technical Reports Server (NTRS)

    Lewis, Charles M.; Heidorn, P. B.

    1991-01-01

    Two machine-learning methods are presently used to characterize the avoidance strategies used by skilled pilots in simulated aircraft encounters, and a general framework for the characterization of the strategic components of skilled behavior via qualitative representation of situations and responses is presented. Descriptions of pilot maneuvers that were 'conceptually equivalent' were ascertained by a concept-learning algorithm in conjunction with a classifier system that employed a generic algorithm; satisficing and 'buggy' strategies were thereby revealed.

  13. In-flight AHS MTF measurements

    NASA Astrophysics Data System (ADS)

    Viallefont-Robinet, Françoise; Fontanilles, Guillaume; de Miguel, Eduardo

    2008-10-01

    The disposal of couples of images of the same landscape acquired with two spatial resolutions gives the opportunity to assess the in-flight Modulation Transfer Function (MTF) of the lower resolution sensor in the common spectral bands. For each couple, the higher resolution image stands for the landscape so that the ratio of the spectra obtained by FFT of the two images, gives the lower resolution sensor MTF. This paper begins with a brief recall of the method including the aliasing correction. The next step presents the data to be processed, provided by the Instituto Nacional de Tecnica Aeroespacial (INTA). The model of the AHS MTF is described. The presentation of the corresponding AHS results naturally follows. Last part of the paper consists in a comparison with other measurements: measurements obtained with the edge method and laboratory measurements.

  14. Mars Exploration Rovers Propulsive Maneuver Design

    NASA Technical Reports Server (NTRS)

    Potts, Christopher L.; Raofi, Behzad; Kangas, Julie A.

    2004-01-01

    The Mars Exploration Rovers Spirit and Opportunity successfully landed respectively at Gusev Crater and Meridiani Planum in January 2004. The rovers are essentially robotic geologists, sent on a mission to search for evidence in the rocks and soil pertaining to the historical presence of water and the ability to possibly sustain life. In order to conduct NASA's 'follow the water' strategy on opposite sides of the planet Mars, an interplanetary journey of over 300 million miles culminated with historic navigation precision. Rigorous trajectory targeting and control was necessary to achieve the atmospheric entry requirements for the selected landing sites. The propulsive maneuver design challenge was to meet or exceed these requirements while preserving the necessary design margin to accommodate additional project concerns. Landing site flexibility was maintained for both missions after launch, and even after the first trajectory correction maneuver for Spirit. The final targeting strategy was modified to improve delivery performance and reduce risk after revealing constraining trajectory control characteristics. Flight results are examined and summarized for the six trajectory correction maneuvers that were planned for each mission.

  15. Identification of aerodynamic models for maneuvering aircraft

    NASA Technical Reports Server (NTRS)

    Chin, Suei; Lan, C. Edward

    1990-01-01

    Due to the requirement of increased performance and maneuverability, the flight envelope of a modern fighter is frequently extended to the high angle-of-attack regime. Vehicles maneuvering in this regime are subjected to nonlinear aerodynamic loads. The nonlinearities are due mainly to three-dimensional separated flow and concentrated vortex flow that occur at large angles of attack. Accurate prediction of these nonlinear airloads is of great importance in the analysis of a vehicle's flight motion and in the design of its flight control system. A satisfactory evaluation of the performance envelope of the aircraft may require a large number of coupled computations, one for each change in initial conditions. To avoid the disadvantage of solving the coupled flow-field equations and aircraft's motion equations, an alternate approach is to use a mathematical modeling to describe the steady and unsteady aerodynamics for the aircraft equations of motion. Aerodynamic forces and moments acting on a rapidly maneuvering aircraft are, in general, nonlinear functions of motion variables, their time rate of change, and the history of maneuvering. A numerical method was developed to analyze the nonlinear and time-dependent aerodynamic response to establish the generalized indicial function in terms of motion variables and their time rates of change.

  16. 12 CFR Appendixes A-H to Subpart A... - Appendixes A-H to Subpart A of Part 702

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 7 2013-01-01 2013-01-01 false Appendixes A-H to Subpart A of Part 702 A Appendixes A-H to Subpart A of Part 702 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS PROMPT CORRECTIVE ACTION Net Worth Classification Pt. 702, Apps. Appendixes A-H...

  17. 12 CFR Appendixes A-H to Subpart A... - Appendixes A-H to Subpart A of Part 702

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Appendixes A-H to Subpart A of Part 702 A Appendixes A-H to Subpart A of Part 702 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS PROMPT CORRECTIVE ACTION Net Worth Classification Pt. 702, Apps. Appendixes A-H...

  18. 12 CFR Appendixes A-H to Subpart A... - Appendixes A-H to Subpart A of Part 702

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 7 2012-01-01 2012-01-01 false Appendixes A-H to Subpart A of Part 702 A Appendixes A-H to Subpart A of Part 702 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS PROMPT CORRECTIVE ACTION Net Worth Classification Pt. 702, Apps. Appendixes A-H...

  19. 12 CFR Appendixes A-H to Subpart A... - Appendixes A-H to Subpart A of Part 702

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Appendixes A-H to Subpart A of Part 702 A Appendixes A-H to Subpart A of Part 702 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS PROMPT CORRECTIVE ACTION Net Worth Classification Pt. 702, Apps. Appendixes A-H...

  20. 12 CFR Appendixes A-H to Subpart A... - Appendixes A-H to Subpart A of Part 702

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Appendixes A-H to Subpart A of Part 702 A Appendixes A-H to Subpart A of Part 702 Banks and Banking NATIONAL CREDIT UNION ADMINISTRATION REGULATIONS AFFECTING CREDIT UNIONS PROMPT CORRECTIVE ACTION Net Worth Classification Pt. 702, Apps. Appendixes A-H...

  1. Close proximity spacecraft maneuvers near irregularly shaped small bodies: Hovering, translation, and descent

    NASA Astrophysics Data System (ADS)

    Broschart, Stephen B.

    Recently there has been significant interest in sending spacecraft to small-bodies in our solar system, such as asteroids, comets, and small planetary satellites, for the purpose of scientific study. It is believed that the composition of these bodies, unchanged for billions of years, can aid in understanding the formative period of our solar system. However, missions to small-bodies are difficult from a dynamical standpoint, complicated by the irregular shape and gravitational potential of the small-body, strong perturbations from solar radiation pressure and third body gravity, and significant uncertainty in the small-body parameters. This dissertation studies the spacecraft maneuvers required to enable a sampling mission in this unique dynamical environment, including station-keeping (hovering), translation, and descent. The bulk of this work studies hovering maneuvers, where equilibrium is created at an arbitrary position by using thrusters to null the nominal spacecraft acceleration. Contributions include a numerical study of previous results on the stability of hovering, a definition of the zero-velocity surface that exists in the vicinity of hovering spacecraft (for time-invariant dynamics), and a dead-band hovering controller design that ensures the trajectory is bounded within a prescribed region. It is found that bounded hovering near the surface of a small-body can often be achieved using dead-band control on only one direction of motion; altitude measurements alone are often sufficient to implement this control. A constant thrust strategy for translation and descent maneuvers appropriate for autonomous implementation is also presented and shown to accurately complete maneuvers in the vicinity of the initial position. Sensitivity analysis studies the effects of parameter uncertainty on these maneuvers. The theory presented within is supported throughout with numerical analysis (software tools are described within) and test cases using models of real

  2. Development and Evaluation of a Performance Modeling Flight Test Approach Based on Quasi Steady-State Maneuvers

    NASA Technical Reports Server (NTRS)

    Yechout, T. R.; Braman, K. B.

    1984-01-01

    The development, implementation and flight test evaluation of a performance modeling technique which required a limited amount of quasisteady state flight test data to predict the overall one g performance characteristics of an aircraft. The concept definition phase of the program include development of: (1) the relationship for defining aerodynamic characteristics from quasi steady state maneuvers; (2) a simplified in flight thrust and airflow prediction technique; (3) a flight test maneuvering sequence which efficiently provided definition of baseline aerodynamic and engine characteristics including power effects on lift and drag; and (4) the algorithms necessary for cruise and flight trajectory predictions. Implementation of the concept include design of the overall flight test data flow, definition of instrumentation system and ground test requirements, development and verification of all applicable software and consolidation of the overall requirements in a flight test plan.

  3. Venous return curves obtained from graded series of valsalva maneuvers

    NASA Technical Reports Server (NTRS)

    Mastenbrook, S. M., Jr.

    1974-01-01

    The effects were studied of a graded series of valsalva-like maneuvers on the venous return, which was measured transcutaneously in the jugular vein of an anesthetized dog, with the animal serving as its own control. At each of five different levels of central venous pressure, the airway pressure which just stopped venous return during each series of maneuvers was determined. It was found that this end-point airway pressure is not a good estimator of the animal's resting central venous pressure prior to the simulated valsalva maneuver. It was further found that the measured change in right atrial pressure during a valsalva maneuver is less than the change in airway pressure during the same maneuver, instead of being equal, as had been expected. Relative venous return curves were constructed from the data obtained during the graded series of valsalva maneuvers.

  4. Slew maneuvers of Spacecraft Control Laboratory Experiment (SCOLE)

    NASA Technical Reports Server (NTRS)

    Kakad, Yogendra P.

    1992-01-01

    This is the final report on the dynamics and control of slew maneuvers of the Spacecraft Control Laboratory Experiment (SCOLE) test facility. The report documents the basic dynamical equation derivations for an arbitrary large angle slew maneuver as well as the basic decentralized slew maneuver control algorithm. The set of dynamical equations incorporate rigid body slew maneuver and three dimensional vibrations of the complete assembly comprising the rigid shuttle, the flexible beam, and the reflector with an offset mass. The analysis also includes kinematic nonlinearities of the entire assembly during the maneuver and the dynamics of the interactions between the rigid shuttle and the flexible appendage. The equations are simplified and evaluated numerically to include the first ten flexible modes to yield a model for designing control systems to perform slew maneuvers. The control problem incorporates the nonlinear dynamical equations and is expressed in terms of a two point boundary value problem.

  5. 42 CFR 37.91 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SPECIFICATIONS FOR MEDICAL EXAMINATIONS OF COAL MINERS Spirometry Examinations § 37.91 Definitions. Definitions... spirometry examinations. FET means forced expiratory time, which is the time from the beginning of exhalation... means peak expiratory flow, which is the maximal airflow during a forced expiratory maneuver....

  6. Large planar maneuvers for articulated flexible manipulators

    NASA Technical Reports Server (NTRS)

    Huang, Jen-Kuang; Yang, Li-Farn

    1988-01-01

    An articulated flexible manipulator carried on a translational cart is maneuvered by an active controller to perform certain position control tasks. The nonlinear dynamics of the articulated flexible manipulator are derived and a transformation matrix is formulated to localize the nonlinearities within the inertia matrix. Then a feedback linearization scheme is introduced to linearize the dynamic equations for controller design. Through a pole placement technique, a robust controller design is obtained by properly assigning a set of closed-loop desired eigenvalues to meet performance requirements. Numerical simulations for the articulated flexible manipulators are given to demonstrate the feasibility and effectiveness of the proposed position control algorithms.

  7. Coordination Logic for Repulsive Resolution Maneuvers

    NASA Technical Reports Server (NTRS)

    Narkawicz, Anthony J.; Munoz, Cesar A.; Dutle, Aaron M.

    2016-01-01

    This paper presents an algorithm for determining the direction an aircraft should maneuver in the event of a potential conflict with another aircraft. The algorithm is implicitly coordinated, meaning that with perfectly reliable computations and information, it will in- dependently provide directional information that is guaranteed to be coordinated without any additional information exchange or direct communication. The logic is inspired by the logic of TCAS II, the airborne system designed to reduce the risk of mid-air collisions between aircraft. TCAS II provides pilots with only vertical resolution advice, while the proposed algorithm, using a similar logic, provides implicitly coordinated vertical and horizontal directional advice.

  8. Maneuvering technology for advanced fighter aircraft

    NASA Technical Reports Server (NTRS)

    Alexander, Michael G.; Harris, Scott H.; Byers, Richard H.

    1992-01-01

    The need for increased maneuverability has its genesis from the first aerial combat engagement when two adversaries entangled themselves in a deadly aerial dance trying to gain the advantage over the other. It has only been in the past two decades that technologies have been investigated to increase aircraft control at maneuver attitudes that are typically dominated by highly separated flows. These separated flow regions are aggravated by advanced fighter aircraft shapes required to defeat an electronic enemy. This paper discusses passive and active devices that can be used to enhance the maneuverability of advanced fighter aircraft through vortex flow control, boundary layer control, and innovative flow manipulation.

  9. Ride quality of terminal-area flight maneuvers

    NASA Technical Reports Server (NTRS)

    Schoonover, W. E., Jr.

    1975-01-01

    Complex terminal-area flight maneuvers being considered for airline operations may not be acceptable to passengers. To provide technology in this area, a series of flight experiments was conducted by NASA using the U. S. Air Force Total In-Flight Simulator (TIFS) aircraft to obtain subjective responses of a significant number of passenger test subjects to closely controlled and repeatable flight maneuvers. Regression analysis of the data produced a mathematical model which closely predicts mean passenger ride-comfort rating as a function of the rms six-degree-of-freedom aircraft motions during the maneuver. This ride-comfort model was exercised to examine various synthesized flight maneuvers.

  10. Artificial immune system approach for air combat maneuvering

    NASA Astrophysics Data System (ADS)

    Kaneshige, John; Krishnakumar, Kalmanje

    2007-04-01

    Since future air combat missions will involve both manned and unmanned aircraft, the primary motivation for this research is to enable unmanned aircraft with intelligent maneuvering capabilities. During air combat maneuvering, pilots use their knowledge and experience of maneuvering strategies and tactics to determine the best course of action. As a result, we try to capture these aspects using an artificial immune system approach. The biological immune system protects the body against intruders by recognizing and destroying harmful cells or molecules. It can be thought of as a robust adaptive system that is capable of dealing with an enormous variety of disturbances and uncertainties. However, another critical aspect of the immune system is that it can remember how previous encounters were successfully defeated. As a result, it can respond faster to similar encounters in the future. This paper describes how an artificial immune system is used to select and construct air combat maneuvers. These maneuvers are composed of autopilot mode and target commands, which represent the low-level building blocks of the parameterized system. The resulting command sequences are sent to a tactical autopilot system, which has been enhanced with additional modes and an aggressiveness factor for enabling high performance maneuvers. Just as vaccinations train the biological immune system how to combat intruders, training sets are used to teach the maneuvering system how to respond to different enemy aircraft situations. Simulation results are presented, which demonstrate the potential of using immunized maneuver selection for the purposes of air combat maneuvering.

  11. Control concept for maneuvering in hypersonic flight

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Lallman, Frederick J.

    1991-01-01

    This research investigates an approach to provide precise, coordinated maneuver control during excursions from a hypersonic cruise flight path while observing the necessary flight condition constraints. The approach achieves specified guidance commands by resolving altitude and cross-range errors into a load factor and bank angle command through a coordinate transformation which acts as an interface between outer loop guidance controls and inner loop flight controls. This interface, referred to as a 'resolver', applies constraints on angle-of-attack and dynamic pressure perturbations while prioritizing altitude regulation over crossrange. An unpiloted test simulation, in which the resolver was used to drive inner-loop flight controls, produced time histories of responses to guidance commands at Mach numbers of 6, 10, 15, and 20. It is shown that angle-of-attack and throttle perturbation constraints, combined with high-speed flight effects and the desire to maintain constant dynamic pressure, significantly impact the maneuver envelope for a hypersonic vehicle. Turn rate, climb rate, and descent rate limits are expressed in terms of these constraints.

  12. Thruster configurations for maneuvering heavy payloads

    NASA Technical Reports Server (NTRS)

    Tsugawa, Roy K.; Draznin, Michael E.; Dabney, Richard W.

    1991-01-01

    The Cargo Transfer Vehicle (CTV) will be required to perform six degree of freedom (6 DOF) maneuvers while carrying a wide range of payloads varying from 100,000 lbm to no payload. The current baseline design configuration for the CTV uses a forward propulsion module (FPM) mounted in front of the payload with the CTV behind the payload so that the center of gravity (CG) of the combined stack is centered between the thruster sets. This allows for efficient rotations and translations of heavy payloads in all directions; however, the FPM is a costly item, so it is desirable to find design solutions that do not require the FPM. This presentation provides an overview of the analysis of the FPM requirements for the CTV. In this study, only the reaction control system (RCS) thruster configurations are considered for 6 DOF maneuvers of various CTV cargo configurations. An important output of this study are the viable alternative thruster configurations that eliminate the need for the FPM. Initial results were derived using analytical techniques and simulation analysis tools. Results from the preliminary analysis were validated using our 6 DOF simulation.

  13. General and Specific Strategies Used to Facilitate Locomotor Maneuvers

    PubMed Central

    Wu, Mengnan; Matsubara, Jesse H.; Gordon, Keith E.

    2015-01-01

    People make anticipatory changes in gait patterns prior to initiating a rapid change of direction. How they prepare will change based on their knowledge of the maneuver. To investigate specific and general strategies used to facilitate locomotor maneuvers, we manipulated subjects’ ability to anticipate the direction of an upcoming lateral “lane-change” maneuver. To examine specific anticipatory adjustments, we observed the four steps immediately preceding a maneuver that subjects were instructed to perform at a known time in a known direction. We hypothesized that to facilitate a specific change of direction, subjects would proactively decrease margin of stability in the future direction of travel. Our results support this hypothesis: subjects significantly decreased lateral margin of stability by 69% on the side ipsilateral to the maneuver during only the step immediately preceding the maneuver. This gait adaptation may have improved energetic efficiency and simplified the control of the maneuver. To examine general anticipatory adjustments, we observed the two steps immediately preceding the instant when subjects received information about the direction of the maneuver. When the maneuver direction was unknown, we hypothesized that subjects would make general anticipatory adjustments that would improve their ability to actively initiate a maneuver in multiple directions. This second hypothesis was partially supported as subjects increased step width and stance phase hip flexion during these anticipatory steps. These modifications may have improved subjects’ ability to generate forces in multiple directions and maintain equilibrium during the onset and execution of the rapid maneuver. However, adapting these general anticipatory strategies likely incurred an additional energetic cost. PMID:26167931

  14. Newspapers and newspaper ink contain agonists for the ah receptor.

    PubMed

    Bohonowych, Jessica E S; Zhao, Bin; Timme-Laragy, Alicia; Jung, Dawoon; Di Giulio, Richard T; Denison, Michael S

    2008-04-01

    Ligand-dependent activation of the aryl hydrocarbon receptor (AhR) pathway leads to a diverse array of biological and toxicological effects. The best-studied ligands for the AhR include polycyclic and halogenated aromatic hydrocarbons, the most potent of which is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, as new AhR ligands are identified and characterized, their structural and physiochemical diversity continues to expand. Our identification of AhR agonists in crude extracts from diverse materials raises questions as to the magnitude and extent of human exposure to AhR ligands through normal daily activities. We have found that solvent extracts of newspapers from countries around the world stimulate the AhR signaling pathway. AhR agonist activity was observed for dimethyl sulfoxide (DMSO), ethanol, and water extracts of printed newspaper, unprinted virgin paper, and black printing ink, where activation of luciferase reporter gene expression was transient, suggesting that the AhR active chemical(s) was metabolically labile. DMSO and ethanol extracts also stimulated AhR transformation and DNA binding, and also competed with [(3)H]TCDD for binding to the AhR. In addition, DMSO extracts of printed newspaper induced cytochrome P450 1A associated 7-ethoxyresorufin-O-deethylase activity in zebrafish embryos in vivo. Although the responsible bioactive chemical(s) remain to be identified, our results demonstrate that newspapers and printing ink contain relatively potent metabolically labile agonists of the AhR. Given the large amount of recycling and reprocessing of newspapers throughout the world, release of these easily extractable AhR agonists into the environment should be examined and their potential effects on aquatic organisms assessed. PMID:18203687

  15. Testing Update on 20 and 25-Ah Lithium Ion Cells

    NASA Technical Reports Server (NTRS)

    Bruce, Gregg C.; Mardikian, Pamella; Edwards, Sherri; Bugga, Kumar; Chin, Keith; Smart, Marshall; Surampudi, Subbarao

    2003-01-01

    Eagle-Picher Energy Products has worked on lithium ion batteries for approximately 8 years. During that period EPEPC developed and delivered several cell sizes on a program funded by the USAF and Canadian DND. Designs are wound cylindrical cells from 7 to 40-Ah. Most cells delivered were approximately 25-Ah due to requirements of Mars missions. Several iterations of cells were manufactured and delivered for evaluation. The first design was 20-Ah, Design I, and the second was a 25-Ah, Design II.

  16. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration... cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the... subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering...

  17. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration... cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the... subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering...

  18. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) Maneuvering balanced conditions. Assuming the airplane to be in equilibrium with zero pitching acceleration... cockpit pitch control is suddenly moved to obtain extreme nose up pitching acceleration. In defining the... subsequent to the time when normal acceleration at the c.g. exceeds the positive limit maneuvering...

  19. 47 CFR 25.282 - Orbit raising maneuvers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Orbit raising maneuvers. 25.282 Section 25.282... Technical Operations § 25.282 Orbit raising maneuvers. A space station authorized to operate in the geostationary satellite orbit under this part is also authorized to transmit in connection with...

  20. 47 CFR 25.282 - Orbit raising maneuvers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 2 2012-10-01 2012-10-01 false Orbit raising maneuvers. 25.282 Section 25.282... Technical Operations § 25.282 Orbit raising maneuvers. A space station authorized to operate in the geostationary satellite orbit under this part is also authorized to transmit in connection with...

  1. 47 CFR 25.282 - Orbit raising maneuvers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 2 2013-10-01 2013-10-01 false Orbit raising maneuvers. 25.282 Section 25.282... Technical Operations § 25.282 Orbit raising maneuvers. A space station authorized to operate in the geostationary satellite orbit under this part is also authorized to transmit in connection with...

  2. 47 CFR 25.282 - Orbit raising maneuvers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 2 2011-10-01 2011-10-01 false Orbit raising maneuvers. 25.282 Section 25.282... Technical Operations § 25.282 Orbit raising maneuvers. A space station authorized to operate in the geostationary satellite orbit under this part is also authorized to transmit in connection with...

  3. 47 CFR 25.282 - Orbit raising maneuvers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 2 2014-10-01 2014-10-01 false Orbit raising maneuvers. 25.282 Section 25.282... Technical Operations § 25.282 Orbit raising maneuvers. A space station authorized to operate in the geostationary satellite orbit under this part is also authorized to transmit in connection with...

  4. Combined problem of slew maneuver control and vibration suppression

    NASA Technical Reports Server (NTRS)

    Kakad, Y. P.

    1988-01-01

    The combined problem of slew maneuver control and vibration suppression of NASA Spacecraft Control Laboratory Experiment (SCOLE) is considered. The coupling between the rigid body modes and flexible modes together with the effect of the control forces on the flexible antenna is discussed. The nonlinearities in the equations are studied in terms of slew maneuver angular velocities.

  5. Combined problem of slew maneuver control and vibration suppression

    NASA Technical Reports Server (NTRS)

    Kakad, Y. P.

    1987-01-01

    The combined problem of slew maneuver control and vibration suppression of NASA Spacecraft Control Laboratory Experiment (SCOLE) is considered. The coupling between the rigid body modes and the flexible modes together with the effect of the control forces on the flexible antenna is discussed. The nonlinearities in the equations are studied in terms of slew maneuver angular velocities.

  6. Performance Evaluation of Evasion Maneuvers for Parallel Approach Collision Avoidance

    NASA Technical Reports Server (NTRS)

    Winder, Lee F.; Kuchar, James K.; Waller, Marvin (Technical Monitor)

    2000-01-01

    Current plans for independent instrument approaches to closely spaced parallel runways call for an automated pilot alerting system to ensure separation of aircraft in the case of a "blunder," or unexpected deviation from the a normal approach path. Resolution advisories by this system would require the pilot of an endangered aircraft to perform a trained evasion maneuver. The potential performance of two evasion maneuvers, referred to as the "turn-climb" and "climb-only," was estimated using an experimental NASA alerting logic (AILS) and a computer simulation of relative trajectory scenarios between two aircraft. One aircraft was equipped with the NASA alerting system, and maneuvered accordingly. Observation of the rates of different types of alerting failure allowed judgement of evasion maneuver performance. System Operating Characteristic (SOC) curves were used to assess the benefit of alerting with each maneuver.

  7. Optimization of Maneuver Execution for Landsat-7 Routine Operations

    NASA Technical Reports Server (NTRS)

    Cox, E. Lucien, Jr.; Bauer, Frank H. (Technical Monitor)

    2000-01-01

    Multiple mission constraints were satisfied during a lengthy, strategic ascent phase. Once routine operations begin, the ongoing concern of maintaining mission requirements becomes an immediate priority. The Landsat-7 mission has tight longitude control box and Earth imaging that requires sub-satellite descending nodal equator crossing times to occur in a narrow 30minute range fifteen (15) times daily. Operationally, spacecraft maneuvers must'be executed properly to maintain mission requirements. The paper will discuss the importance of optimizing the altitude raising and plane change maneuvers, amidst known constraints, to satisfy requirements throughout mission lifetime. Emphasis will be placed not only on maneuver size and frequency but also on changes in orbital elements that impact maneuver execution decisions. Any associated trade-off arising from operations contingencies will be discussed as well. Results of actual altitude and plane change maneuvers are presented to clarify actions taken.

  8. Planar reorientation maneuvers of space multibody systems using internal controls

    NASA Technical Reports Server (NTRS)

    Reyhanoglu, Mahmut; Mcclamroch, N. H.

    1992-01-01

    In this paper a reorientation maneuvering strategy for an interconnection of planar rigid bodies in space is developed. It is assumed that there are no exogeneous torques, and torques generated by joint motors are used as means of control so that the total angular momentum of the multibody system is a constant, assumed to be zero in this paper. The maneuver strategy uses the nonintegrability of the expression for the angular momentum. We demonstrate that large-angle maneuvers can be designed to achieve an arbitrary reorientation of the multibody system with respect to an inertial frame. The theoretical background for carrying out the required maneuvers is briefly summarized. Specifications and computer simulations of a specific reorientation maneuver, and the corresponding control strategies, are described.

  9. Maneuver Classification for Aircraft Fault Detection

    NASA Technical Reports Server (NTRS)

    Oza, Nikunj C.; Tumer, Irem Y.; Tumer, Kagan; Huff, Edward M.

    2003-01-01

    Automated fault detection is an increasingly important problem in aircraft maintenance and operation. Standard methods of fault detection assume the availability of either data produced during all possible faulty operation modes or a clearly-defined means to determine whether the data provide a reasonable match to known examples of proper operation. In the domain of fault detection in aircraft, identifying all possible faulty and proper operating modes is clearly impossible. We envision a system for online fault detection in aircraft, one part of which is a classifier that predicts the maneuver being performed by the aircraft as a function of vibration data and other available data. To develop such a system, we use flight data collected under a controlled test environment, subject to many sources of variability. We explain where our classifier fits into the envisioned fault detection system as well as experiments showing the promise of this classification subsystem.

  10. The wire anchor loop traction (WALT) maneuver.

    PubMed

    Effendi, Khaled; Sacho, Raphael Hillel; Belzile, François; Marotta, Thomas R

    2016-02-01

    Crossing the neck of large complex intracranial aneurysms for the purposes of stent deployment can be challenging using standard over the wire techniques. We describe a novel yet simple technique for straightening out the loop formed within a large intracranial aneurysm, which is often required in order to cross the aneurysm neck into the distal branch. Both the microcatheter and microwire are initially introduced into the distal vasculature, followed by withdrawal of the microwire to a point parallel to the distal exiting branch. The microcatheter and microwire are then gently withdrawn and a series of maneuvers to gradually reduce the loop is performed, obviating the need for distal purchase in the form of a stent, balloon, or coil, which have previously been described to maintain distal purchase. PMID:25634903

  11. Orbital Maneuvering Vehicle space station communications design

    NASA Technical Reports Server (NTRS)

    Arndt, D.; Novosad, S. W.; Tu, K.; Loh, Y. C.; Kuo, Y. S.

    1988-01-01

    The authors present an Orbital Maneuvering Vehicle space station communications systems design approach which is intended to satisfy the stringent link requirements. The operational scenario, system configuration, signal design, antenna system management, and link performance analysis are discussed in detail. It is shown that the return link can transmit up to 21.6 Mb/s and maintain at least a 3-dB link margin through proper power and antenna management control at a maximum distance of 37 km. It is suggested that the proposed system, which is compatible with the space station multiple-access system, can be a model for other space station interoperating elements or users to save the development cost and reduce the technical and schedule risks.

  12. Classification of Aircraft Maneuvers for Fault Detection

    NASA Technical Reports Server (NTRS)

    Oza, Nikunj C.; Tumer, Irem Y.; Tumer, Kagan; Huff, Edward M.; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Automated fault detection is an increasingly important problem in aircraft maintenance and operation. Standard methods of fault detection assume the availability of either data produced during all possible faulty operation modes or a clearly-defined means to determine whether the data is a reasonable match to known examples of proper operation. In our domain of fault detection in aircraft, the first assumption is unreasonable and the second is difficult to determine. We envision a system for online fault detection in aircraft, one part of which is a classifier that predicts the maneuver being performed by the aircraft as a function of vibration data and other available data. We explain where this subsystem fits into our envisioned fault detection system as well its experiments showing the promise of this classification subsystem.

  13. Classification of Aircraft Maneuvers for Fault Detection

    NASA Technical Reports Server (NTRS)

    Oza, Nikunj; Tumer, Irem Y.; Tumer, Kagan; Huff, Edward M.; Koga, Dennis (Technical Monitor)

    2002-01-01

    Automated fault detection is an increasingly important problem in aircraft maintenance and operation. Standard methods of fault detection assume the availability of either data produced during all possible faulty operation modes or a clearly-defined means to determine whether the data provide a reasonable match to known examples of proper operation. In the domain of fault detection in aircraft, the first assumption is unreasonable and the second is difficult to determine. We envision a system for online fault detection in aircraft, one part of which is a classifier that predicts the maneuver being performed by the aircraft as a function of vibration data and other available data. To develop such a system, we use flight data collected under a controlled test environment, subject to many sources of variability. We explain where our classifier fits into the envisioned fault detection system as well as experiments showing the promise of this classification subsystem.

  14. Horizontal tail loads in maneuvering flight

    NASA Technical Reports Server (NTRS)

    Pearson, Henry A; Mcgowan, William A; Donegan, James J

    1951-01-01

    A method is given for determining the horizontal tail loads in maneuvering flight. The method is based upon the assignment of a load-factor variation with time and the determination of a minimum time to reach peak load factor. The tail load is separated into various components. Examination of these components indicated that one of the components was so small that it could be neglected for most conventional airplanes; therefore, the number of aerodynamic parameters needed in this computation of tail loads was reduced to a minimum. In order to illustrate the method, as well as to show the effect of the main variables, a number of examples are given. Some discussion is given regarding the determination of maximum tail loads, maximum pitching accelerations, and maximum pitching velocities obtainable.

  15. Analysis of ship maneuvering data from simulators

    NASA Astrophysics Data System (ADS)

    Frette, V.; Kleppe, G.; Christensen, K.

    2011-03-01

    We analyze complex manuevering histories of ships obtained from training sessions on bridge simulators. Advanced ships are used in fields like offshore oil exploration: dive support vessels, supply vessels, anchor handling vessels, tugs, cable layers, and multi-purpose vessels. Due to high demands from the operations carried out, these ships need to have very high maneuverability. This is achieved through a propulsion system with several thrusters, water jets, and rudders in addition to standard propellers. For some operations, like subsea maintenance, it is crucial that the ship accurately keeps a fixed position. Therefore, bridge systems usually incorporate equipment for Dynamic Positioning (DP). DP is a method to keep ships and semi submersible rigs in a fixed position using the propulsion systems instead of anchors. It may also be used for sailing a vessel from one position to another along a predefined route. Like an autopilot on an airplane, DP may operate without human involvement. The method relies on accurate determination of position from external reference systems like GPS, as well as a continuously adjusted mathematical model of the ship and external forces from wind, waves and currents. In a specific simulator exercise for offshore crews, a ship is to be taken up to an installation consisting of three nearby oil platforms connected by bridges (Frigg field, North Sea), where a subsea inspection is to be carried out. Due to the many degrees of freedom during maneuvering, including partly or full use of DP, the chosen routes vary significantly. In this poster we report preliminary results on representations of the complex maneuvering histories; representations that allow comparison between crew groups, and, possibly, sorting of the different strategic choices behind.

  16. Cerebrovascular effects of the thigh cuff maneuver.

    PubMed

    Panerai, R B; Saeed, N P; Robinson, T G

    2015-04-01

    Arterial hypotension can be induced by sudden release of inflated thigh cuffs (THC), but its effects on the cerebral circulation have not been fully described. In nine healthy subjects [aged 59 (9) yr], bilateral cerebral blood flow velocity (CBFV) was recorded in the middle cerebral artery (MCA), noninvasive arterial blood pressure (BP) in the finger, and end-tidal CO2 (ETCO2) with nasal capnography. Three THC maneuvers were performed in each subject with cuff inflation 20 mmHg above systolic BP for 3 min before release. Beat-to-beat values were extracted for mean CBFV, BP, ETCO2 , critical closing pressure (CrCP), resistance-area product (RAP), and heart rate (HR). Time-varying estimates of the autoregulation index [ARI(t)] were also obtained using an autoregressive-moving average model. Coherent averages synchronized by the instant of cuff release showed significant drops in mean BP, CBFV, and RAP with rapid return of CBFV to baseline. HR, ETCO2 , and ARI(t) were transiently increased, but CrCP remained relatively constant. Mean values of ARI(t) for the 30 s following cuff release were not significantly different from the classical ARI [right MCA 5.9 (1.1) vs. 5.1 (1.6); left MCA 5.5 (1.4) vs. 4.9 (1.7)]. HR was strongly correlated with the ARI(t) peak after THC release (in 17/22 and 21/24 recordings), and ETCO2 was correlated with the subsequent drop in ARI(t) (19/22 and 20/24 recordings). These results suggest a complex cerebral autoregulatory response to the THC maneuver, dominated by myogenic mechanisms and influenced by concurrent changes in ETCO2 and possible involvement of the autonomic nervous system and baroreflex. PMID:25659488

  17. X-31 in flight - Mongoose Maneuver

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Two X-31 Enhanced Fighter Maneuverability (EFM) demonstrators were flown at the Rockwell International facility, Palmdale, California, and the NASA Dryden Flight Research Center, Edwards, California, to obtain data that may apply to the design of highly-maneuverable next-generation fighters. The program had its first flight on October 11, 1990, in Palmdale; it ended in June 1995. The X-31 program demonstrated the value of thrust vectoring (directing engine exhaust flow) coupled with advanced flight control systems, to provide controlled flight during close-in air combat at very high angles of attack. The result of this increased maneuverability is an aircraft with a significant advantage over conventional fighters. 'Angle-of-attack' (alpha) is an engineering term to describe the angle of an aircraft body and wings relative to its actual flight path. During maneuvers, pilots often fly at extreme angles of attack -- with the nose pitched up while the aircraft continues in its original direction. This can lead to loss of control and result in the loss of the aircraft, pilot or both. Three thrust-vectoring paddles made of graphite epoxy mounted on the exhaust nozzle of the X-31 aircraft directed the exhaust flow to provide control in pitch (up and down) and yaw (right and left) to improve control. The paddles can sustain heat of up to 1,500 degrees centigrade for extended periods of time. In addition the X-31 aircraft were configured with movable forward canards and fixed aft strakes. The canards were small wing-like structures set on the wing line between the nose and the leading edge of the wing. The strakes were set on the same line between the trailing edge of the wing and the engine exhaust. Both supplied additional control in tight maneuvering situations. The X-31 research program produced technical data at high angles of attack. This information is giving engineers and aircraft designers a better understanding of aerodynamics, effectiveness of flight controls

  18. AhR sensing of bacterial pigments regulates antibacterial defence.

    PubMed

    Moura-Alves, Pedro; Faé, Kellen; Houthuys, Erica; Dorhoi, Anca; Kreuchwig, Annika; Furkert, Jens; Barison, Nicola; Diehl, Anne; Munder, Antje; Constant, Patricia; Skrahina, Tatsiana; Guhlich-Bornhof, Ute; Klemm, Marion; Koehler, Anne-Britta; Bandermann, Silke; Goosmann, Christian; Mollenkopf, Hans-Joachim; Hurwitz, Robert; Brinkmann, Volker; Fillatreau, Simon; Daffe, Mamadou; Tümmler, Burkhard; Kolbe, Michael; Oschkinat, Hartmut; Krause, Gerd; Kaufmann, Stefan H E

    2014-08-28

    The aryl hydrocarbon receptor (AhR) is a highly conserved ligand-dependent transcription factor that senses environmental toxins and endogenous ligands, thereby inducing detoxifying enzymes and modulating immune cell differentiation and responses. We hypothesized that AhR evolved to sense not only environmental pollutants but also microbial insults. We characterized bacterial pigmented virulence factors, namely the phenazines from Pseudomonas aeruginosa and the naphthoquinone phthiocol from Mycobacterium tuberculosis, as ligands of AhR. Upon ligand binding, AhR activation leads to virulence factor degradation and regulated cytokine and chemokine production. The relevance of AhR to host defence is underlined by heightened susceptibility of AhR-deficient mice to both P. aeruginosa and M. tuberculosis. Thus, we demonstrate that AhR senses distinct bacterial virulence factors and controls antibacterial responses, supporting a previously unidentified role for AhR as an intracellular pattern recognition receptor, and identify bacterial pigments as a new class of pathogen-associated molecular patterns. PMID:25119038

  19. Performance of AEA 80 Ah Battery under GEO Profiles

    NASA Technical Reports Server (NTRS)

    Russel, N.; Curzon, D.; Ng, K.; Lee, L.; Rao, G.

    2004-01-01

    This viewgraph presentation is divided into the following sections: 1) AEA Geosynchronous Earth Orbit (GEO) Life Testing; 2) AEA/Goddard Space Flight Center (GSFC) 20 Ah Battery; 3) AEA/GSFC 80 Ah Battery; 4) Solar Dynamic Observatory (SDO) Life Test; 5) Test Results; 6) Correlation; 7) Conclusions.

  20. Induction of AhR-Mediated Gene Transcription by Coffee

    PubMed Central

    Ishikawa, Toshio; Takahashi, Satoshi; Morita, Koji; Okinaga, Hiroko; Teramoto, Tamio

    2014-01-01

    Background Aryl hydrocarbon receptor (AhR) is classically known to be activated by xenobiotics such as dioxins and polycyclic aromatic hydrocarbons (PAHs). Although it has been reported that PAHs are contained in roasted coffee beans, in general coffee beverages are not considered to be AhR activators. We tested whether exposure to coffee would activate AhR in cultured cells. Methods HepG2 cells stably expressing an AhR-responsive reporter gene were treated with coffee samples. Also, expression of CYP1A1, an endogenous AhR-responsive gene, was quantitated by RT-PCR and Western blotting in HepG2, Caco-2, and MCF-7 cells, after treatment with coffee. In order to obtain sensitive and reproducible results, all the experiments were performed with the cells placed in either phosphate-buffered saline (PBS) or pure serum, instead of routinely-used culture medium, whose intrinsic AhR-stimulating activity turned out to be so strong as to interfere with the analyses. Results All the coffee samples tested robustly stimulated AhR-mediated transcription in the reporter gene assays. Of note, to what extent coffee and other AhR agonists activated AhR was different, depending on whether the experiments were done in PBS or serum. CYP1A1 mRNA was induced by coffee, in HepG2, Caco-2, and MCF-7 cells placed in either PBS or serum. CYP1A1 protein expression, which was not detected in these cells incubated in PBS, was also increased by coffee in cells placed in serum. Conclusions By using culture medium-free experimental settings, we have shown that coffee is a strong AhR activator. Our observation may help elucidate as-yet-unrecognized effects of coffee on human health. PMID:25007155

  1. Dynamics of spacecraft control laboratory experiment (SCOLE) slew maneuvers

    NASA Technical Reports Server (NTRS)

    Kakad, Y. P.

    1987-01-01

    This is the first of two reports on the dynamics and control of slewing maneuvers of the NASA Spacecraft Control Laboratory Experiment (SCOLE). In this report, the dynamics of slewing maneuvers of SCOLE are developed in terms of an arbitrary maneuver about any given axis. The set of dynamical equations incorporate rigid-body slew maneuver and three-dimensional vibrations of the complete assembly comprising the rigid shuttle, the flexible beam, and the reflector with an offset mass. The analysis also includes kinematic nonlinearities of the entire assembly during the maneuver and the dynamics of the interaction between the rigid shuttle and the flexible appendage. The final set of dynamical equations obtained for slewing maneuvers is highly nonlinear and coupled in terms of the flexible modes and the rigid-body modes. The equations are further simplified and evaluated numerically to include the first ten flexible modes and the SCOLE data to yield a model for designing control systems to perform slew maneuvers.

  2. Constellation Mission Operation Working Group: ESMO Maneuver Planning Process Review

    NASA Technical Reports Server (NTRS)

    Moyer, Eric

    2015-01-01

    The Earth Science Mission Operation (ESMO) Project created an Independent Review Board to review our Conjunction Risk evaluation process and Maneuver Planning Process to identify improvements that safely manages mission conjunction risks, maintains ground track science requirements, and minimizes overall hours expended on High Interest Events (HIE). The Review Board is evaluating the current maneuver process which requires support by multiple groups. In the past year, there have been several changes to the processes although many prior and new concerns exist. This presentation will discuss maneuver process reviews and Board comments, ESMO assessment and path foward, ESMO future plans, recent changes and concerns.

  3. Maneuver Design for the Juno Mission: Inner Cruise

    NASA Technical Reports Server (NTRS)

    Pavlak, Thomas A.; Frauenholz, Raymond B.; Bordi, John J.; Kangas, Julie A.; Helfrich, Clifford E.

    2014-01-01

    The Juno spacecraft launched in August 2011 and, following a successful Earth flyby in October 2013, is on course for a nominal orbit insertion at Jupiter in July 2016. This paper examines the design and execution of deterministic and statistical trajectory correction maneuvers during the first approximately 27 months of post-launch operations that defined the "Inner Cruise" phase of the Juno mission. Topics of emphasis include the two deep space maneuvers, Earth flyby altitude biasing strategy, and the sequence of trajectory correction maneuvers executed in the weeks prior to the successful Earth gravity assist.

  4. Object Correlation and Maneuver Detection Using Optimal Control Performance Metrics

    NASA Astrophysics Data System (ADS)

    Holzinger, M.; Scheeres, D.

    2010-09-01

    Object correlation and maneuver detection are persistent problems in space surveillance and space object catalog maintenance. This paper demonstrates the utility of using quadratic trajectory control cost, an analog to the trajectory L2-norm in control, as a distance metric with which to both correlate object tracks and detect maneuvers using Uncorrelated Tracks (UCTs), real-time sensor measurement residuals, and prior state uncertainty. State and measurement uncertainty are incorporated into the computation, and distributions of optimal control usage are computed. Both UCT correlation as well as maneuver detection are demonstrated in several scenarios Potential avenues for future research and contributions are summarized.

  5. Cassini-Huygens Maneuver Experience: Ending the Prime Mission

    NASA Technical Reports Server (NTRS)

    Goodson, Troy D.; Ballard, Christopher G.; Gist, Emily M.; Hahn, Yungsun; Stumpf, Paul W.; Wagner, Sean V.; Williams, Powtawche N.

    2008-01-01

    The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year cruise, it entered a Saturnian orbit for a four-year, prime mission. This paper highlights significant maneuver activities performed during the last year of the prime mission. Specifically, results of 42 recent maneuvers are presented. Many maneuvers have been skipped, saving fuel and flight team effort. The system has performed more accurately than the pre-launch expectations and requirements. This is in large part why the Cassini-Huygens spacecraft has been navigated with tremendous success during the prime mission.

  6. Nonlinear slew maneuver dynamics of large flexible spacecrafts

    NASA Technical Reports Server (NTRS)

    Kakad, Y. P.

    1990-01-01

    In this paper, the dynamics of three-dimensional, large-angle arbitrary slew maneuvers of a large flexible spacecraft are developed. The dynamical equations obtained allow maneuver specifications about any axis and are highly nonlinear. They also include coupling between the rigid orbiter and the flexible appendage and correction for motion stiffness. A decentralized control scheme is utilized for performing the maneuver of the rigidized body and for vibration suppression of the flexible appendage. The method developed in this paper is further applied to NASA Spacecraft Control Laboratory Experiment (SCOLE) test facility.

  7. Cassini - Huygens maneuver experience : cruise and arrival at Saturn

    NASA Technical Reports Server (NTRS)

    Goodson, Troy; Buffington, Brent; Hahn, Yungsun; Strange, Nathan; Wagner, Sean; Wong, Mau

    2005-01-01

    The Cassini-Huygens mission to Saturn and Titan was launched in 1997. It is an international effort to study the Saturnian system. Cassini-Huygens' interplanetary cruise delivered the spacecraft to Saturn in 2004. It also made use of many propulsive maneuvers, both statistical and deterministic. Maneuver-related analysis and performance for latter half of cruise is reported. The system has performed more accurately than the pre-launch expectations and requirements. Additionally, some maneuvers have already been skipped, saving propellant and flight team effort. Analysis of historical execution error data is presented.

  8. Optimal large-angle maneuvers with vibration suppression

    NASA Technical Reports Server (NTRS)

    Turner, J. D.; Chun, H. M.; Junkins, J. L.

    1983-01-01

    Some methods and applications which determine optimal maneuver controls are overviewed. The main aspects of optimal control theory are summarized and the essential ideas involved in a class of methods ('continuation' or 'homotopy' methods) which are useful in solving the resulting two-point boundary value problems are discussed. Several low dimensioned, nonlinear maneuvers of multiple rigid-body configurations using optimal momentum transfer are discussed. Several linear and nonlinear flexible-body maneuvers are then presented and include distributed controls, vibration suppression/arrest, and computational issues. Finally, the key problem areas in which future research appears most urgent are identified.

  9. Topex orbit sustenance maneuver design. [Ocean Topography Experiment spacecraft

    NASA Technical Reports Server (NTRS)

    Kechichian, J. A.

    1982-01-01

    A trade-off analysis between maneuver period, execution errors, and orbit determination uncertainties is carried out for the Ocean Topography Experiment spacecraft for a given nodal equatorial constraint. Semimajor axis and eccentricity are controlled with minimum impulse using the linear theory of optimal transfer between close coplanar near-circular orbits. Ellipses of equal minimum and average maneuver periods are presented in the (3 execution error, 3 orbit determination uncertainty) space for different nodal equatorial constraints enabling the determination of the appropriate combination of execution errors and orbit determination uncertainties that guarantees a mission required minimum maneuver period for a given nodal deadband.

  10. Early Mission Maneuver Operations for the Deep Space Climate Observatory

    NASA Technical Reports Server (NTRS)

    Roberts, Craig; Case, Sara; Reagoso, John

    2015-01-01

    DSCOVR Lissajous Orbit sized such that orbit track never extends beyond 15 degrees from Earth-Sun line (as seen from Earth). Requiring delta-V maneuvers, control orbit to obey a Solar Exclusion Zone (SEZ) cone of half-angle 4 degrees about the Earth-Sun line. Spacecraft should never be less than 4 degrees from solar center as seen from Earth. Following Lissajous Orbit Insertion (LOI), DSCOVR should be in an opening phase that just skirts the 4-degree SEZ. Maximizes time to the point where a closing Lissajous will require avoidance maneuvers to keep it out of the SEZ. Station keeping maneuvers should take no more than 15 minutes

  11. Introducing the “TCDD-Inducible AhR-Nrf2 Gene Battery”

    PubMed Central

    Yeager, Ronnie L.; Reisman, Scott A.; Aleksunes, Lauren M.; Klaassen, Curtis D.

    2009-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces genes via the transcription factor aryl hydrocarbon receptor (AhR), including Cyp1a1, NAD(P)H:quinone oxidoreductase 1 (Nqo1), UDP-glucuronosyltransferase 1a6 (Ugt1a6), and glutathione S-transferase a1 (Gsta1). These genes are referred to as the “AhR gene battery.” However, Nqo1 is also considered a prototypical target gene of the transcription factor nuclear factor erythroid 2–related factor 2 (Nrf2). In mice, TCDD induction of Nrf2 and Nrf2 target, Nqo1, is dependent on AhR, and thus TCDD induction of drug-processing genes may be routed through an AhR-Nrf2 sequence. There has been speculation that Nrf2 may be involved in the TCDD induction of drug-processing genes; however, the data are not definitive. Therefore, to address whether TCDD induction of Nqo1, Ugts, and Gsts is dependent on Nrf2, we conducted the definitive experiment by administering TCDD (50 μg/kg, ip) to Nrf2-null and wild-type (WT) mice and collecting livers 24 h later to quantify the mRNA of drug-processing genes. TCDD induction of Cyp1a1 and Ugt1a1 was similar in WT and Nrf2-null mice, whereas TCDD induction of Ugt1a5 and 1a9 was blunted in Nrf2-null mice. TCDD induced Nqo1, Ugt1a6, 2b34, 2b35, 2b36, UDP-glucuronic acid–synthesizing gene UDP-glucose dehydrogenase, and Gsta1, m1, m2, m3, m6, p2, t2, and microsomal Gst1 in WT mice but not in Nrf2-null mice. Therefore, the present study demonstrates the novel finding that Nrf2 is required for TCDD induction of classical AhR battery genes Nqo1, Ugt1a6, and Gsta1, as well as most Ugt and Gst isoforms in livers of mice. PMID:19474220

  12. Wakes of Maneuvering Bodies in Stratified Fluids

    NASA Astrophysics Data System (ADS)

    Voropayev, S. I.; Fernando, H. J.

    2007-05-01

    We present the results of experimental/theoretical studies on large momentum eddies generated in late wakes of unsteady moving self-propelled bodies in stratified fluids. The experiments were conducted with scaled submarine model at high Reynolds numbers (50,000), corresponding to the fully turbulent flow regime. Dye visualization and PIV were used for flow diagnostics. When a self-propelled body makes a maneuver, e.g. accelerates, it imparts net momentum on the surrounding fluid. We show that in a stratified fluid this leads to impulsive momentum wakes with large, long-lived coherent vortices in the late flows, which may be used as a signature for identification of submarine wakes in oceanic thermocline. First, we consider dynamics and properties of such wakes in a linearly stratified fluid and present a model that permits to predict the main flow characteristics. Second, we consider wakes in a two layer stratified fluid (analog of the upper ocean) and show that such wakes may penetrate to the water surface; we present a model for this phenomenon and propose criteria for the penetration of wake signatures to the water surface in terms of main governing parameters (signature contrast versus confinement number). Finally, we consider the evolution of such momentum wake eddies in the field of decaying background turbulence, which mimics the oceanic thermocline, and show that for the flow configuration studied the contrast number remains sufficiently large and detectable wake imprints survive for a long period of time. Some pertinent estimates for submarines cruising in the upper ocean are also given. For more details see [1-3]. This study was supported by grant from the Office of Naval Research. 1. Voropayev S.I., Fernando H.J.S., Smirnov S.A. & Morrison R.J. 2006. On surface signatures generated by submersed momentum sources. Phys. Fluids, under revision. 2. Voropayev S.I., Fernando H.J.S. & Morrison R.J. 2006. Dipolar eddies in a stratified turbulent flow. J. Fluid

  13. Augmentation of maneuver performance by spanwise blowing

    NASA Technical Reports Server (NTRS)

    Erickson, G. E.; Campbell, J. F.

    1977-01-01

    A generalized wind tunnel model was tested to investigate new component concepts utilizing spanwise blowing to provide improved maneuver characteristics for advanced fighter aircraft. Primary emphasis was placed on high angle of attack performance, stability, and control at subsonic speeds. Spanwise blowing on a 44 deg swept trapezoidal wing resulted in leading edge vortex enhancement with subsequent large vortex-induced lift increments and drag polar improvements at the higher angles of attack. Small deflections of a leading edge flap delayed these lift and drag benefits to higher angles of attack. In addition, blowing was more effective at higher Mach numbers. Spanwise blowing in conjunction with a deflected trailing edge flap resulted in lift and drag benefits that exceeded the summation of the effects of each high lift device acting alone. Asymmetric blowing was an effective lateral control device at the higher angles of attack. Spanwise blowing on the wing reduced horizontal tail loading and improved the lateral-directional stability characteristics of a wing-horizontal tail-vertical tail configuration.

  14. Orbital Maneuvering Vehicle (OMV) remote servicing kit

    NASA Technical Reports Server (NTRS)

    Brown, Norman S.

    1988-01-01

    With the design and development of the Orbital Maneuvering Vehicle (OMV) progressing toward an early 1990 initial operating capability (IOC), a new era in remote space operations will evolve. The logical progression to OMV front end kits would make available in situ satellite servicing, repair, and consummables resupply to the satellite community. Several conceptual design study efforts are defining representative kits (propellant tanks, debris recovery, module servicers); additional focus must also be placed on an efficient combination module servicer and consummables resupply kit. A remote servicer kit of this type would be designed to perform many of the early maintenance/resupply tasks in both nominal and high inclination orbits. The kit would have the capability to exchange Orbital Replacement Units (ORUs), exchange propellant tanks, and/or connect fluid transfer umbilicals. Necessary transportation system functions/support could be provided by interfaces with the OMV, Shuttle (STS), or Expendable Launch Vehicle (ELV). Specific remote servicer kit designs, as well as ground and flight demonstrations of servicer technology are necessary to prepare for the potential overwhelming need. Ground test plans should adhere to the component/system/breadboard test philosophy to assure maximum capability of one-g testing. The flight demonstration(s) would most likely be a short duration, Shuttle-bay experiment to validate servicer components requiring a micro-g environment.

  15. An Immunized Aircraft Maneuver Selection System

    NASA Technical Reports Server (NTRS)

    Karr, Charles L.

    2003-01-01

    The objective of this project, as stated in the original proposal, was to develop an immunized aircraft maneuver selection (IAMS) system. The IAMS system was to be composed of computational and informational building blocks that resemble structures in natural immune systems. The ultimate goal of the project was to develop a software package that could be flight tested on aircraft models. This report describes the work performed in the first year of what was to have been a two year project. This report also describes efforts that would have been made in the final year to have completed the project, had it been continued for the final year. After introductory material is provided in Section 2, the end-of-year-one status of the effort is discussed in Section 3. The remainder of the report provides an accounting of first year efforts. Section 4 provides background information on natural immune systems while Section 5 describes a generic ar&itecture developed for use in the IAMS. Section 6 describes the application of the architecture to a system identification problem. Finally, Section 7 describes steps necessary for completing the project.

  16. Rendezvous radar for the orbital maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Locke, John W.; Olds, Keith; Parks, Howard

    1991-01-01

    This paper describes the development of the Rendezvous Radar Set (RRS) for the Orbital Maneuvering Vehicle (OMV) for the National Aeronautics and Space Administration (NASA). The RRS was to be used to locate, and then provide vectoring information to, target satellites (or Shuttle or Space Station) to aid the OMV in making a minimum-fuel-consumption approach and rendezvous. The RRS design is that of an X-Band, all solid-state, monopulse tracking, frequency hopping, pulse-Doppler radar system. The development of the radar was terminated when the OMV prime contract to TRW was terminated by NASA. At the time of the termination, the development was in the circuit design stage. The system design was virtually completed, the PDR had been held. The RRS design was based on Motorola's experiences, both in the design and production of radar systems for the US Army and in the design and production of hi-rel communications systems for NASA space programs. Experience in these fields was combined with the latest digital signal processor and micro-processor technology to design a light-weight, low-power, spaceborne radar. The antenna and antenna positioner (gimbals) technology developed for the RRS is now being used in the satellite-to-satellite communication link design for Motorola's Iridium telecommunications system.

  17. Improvements to the adaptive maneuvering logic program

    NASA Technical Reports Server (NTRS)

    Burgin, George H.

    1986-01-01

    The Adaptive Maneuvering Logic (AML) computer program simulates close-in, one-on-one air-to-air combat between two fighter aircraft. Three important improvements are described. First, the previously available versions of AML were examined for their suitability as a baseline program. The selected program was then revised to eliminate some programming bugs which were uncovered over the years. A listing of this baseline program is included. Second, the equations governing the motion of the aircraft were completely revised. This resulted in a model with substantially higher fidelity than the original equations of motion provided. It also completely eliminated the over-the-top problem, which occurred in the older versions when the AML-driven aircraft attempted a vertical or near vertical loop. Third, the requirements for a versatile generic, yet realistic, aircraft model were studied and implemented in the program. The report contains detailed tables which make the generic aircraft to be either a modern, high performance aircraft, an older high performance aircraft, or a previous generation jet fighter.

  18. Thruster configurations for maneuvering heavy payloads

    NASA Technical Reports Server (NTRS)

    Tsugawa, Roy K.; Draznin, Michael E.; Dabney, Richard W.

    1991-01-01

    The cargo transfer vehicle (CTV) will be required to perform six degree of freedom (6DOF) maneuvers while carrying a wide range of payloads varying from 100,000 lbm to no payload. The current baseline design configuration for the CTV uses a forward propulsion module (FPM) mounted in front of the payload and the CTV behind the payload so that the center of gravity (CG) of the combined stack is contained between the thruster sets. This allows for efficient rotation and translations of heavy payloads in all directions; however, the FPM is a costly item, so it is desirable to find design solutions which do not require the FPM. This presentation provides an overview of the work performed in analyzing the FPM requirements for the CTV. Specifically, key issues related to thruster configuration requirements for operating the CTV without the FPM, throughout the 100,000 lbm payload to no payload range, will be highlighted. In this study, only the reaction control system (RCS) thruster configurations are considered and the orbit adjust engines are not addressed. An important output of this study is the viable alternative thruster configurations which eliminate the need for the FPM. Initial results were derived using analytical techniques and simulation analysis tools. Results from the preliminary analysis were used as inputs for our 6DOF simulation. The 6DOF simulation was used to validate our design guidelines and to verify the performance of the thruster configurations.

  19. Navigation and control considerations for space based orbital maneuvering systems

    NASA Technical Reports Server (NTRS)

    Brandon, L.

    1984-01-01

    Various design areas of concern in navigation and control of space-based orbital maneuvering systems such as those on the Orbiter are discussed, with note taken of approach maneuvers. Design problems occur in the areas of storage modes, sensing, activation methods, navigation, target/mission determination, rendezvous and docking schemes, reliability, and commonality between low- and high-energy maneuvering vehicles. Navigation may be in autonomous or nonautonomous modes and may include ground-baed computations and commands via the TDRSS or NORAD systems. Autonomous operations would interface with the GPS. All the concepts discussed are significant for the planned orbital transfer and orbital maneuvering vehicles, which would be used to place satellites in orbit and repair or retrieve them.

  20. Halo Orbit Mission Correction Maneuvers Using Optimal Control

    NASA Technical Reports Server (NTRS)

    Lo, M.; Serban, R.; Petzold, L.; Koon, W.; Ross, S.; Marsden, J.; Wilson, R.

    2000-01-01

    This paper addresses the computation of the required trajectory correction maneuvers (TCM) for a halo orbit space mission to compensate for the launch velocity errors introduced by inaccuracies of the launch vehicle.

  1. A near-optimal guidance for cooperative docking maneuvers

    NASA Astrophysics Data System (ADS)

    Ciarcià, Marco; Grompone, Alessio; Romano, Marcello

    2014-09-01

    In this work we study the problem of minimum energy docking maneuvers between two Floating Spacecraft Simulators. The maneuvers are planar and conducted autonomously in a cooperative mode. The proposed guidance strategy is based on the direct method known as Inverse Dynamics in the Virtual Domain, and the nonlinear programming solver known as Sequential Gradient-Restoration Algorithm. The combination of these methods allows for the quick prototyping of near-optimal trajectories, and results in an implementable tool for real-time closed-loop maneuvering. The experimental results included in this paper were obtained by exploiting the recently upgraded Floating Spacecraft-Simulator Testbed of the Spacecraft Robotics Laboratory at the Naval Postgraduate School. A direct performances comparison, in terms of maneuver energy and propellant mass, between the proposed guidance strategy and a LQR controller, demonstrates the effectiveness of the method.

  2. Investigation of Dynamic Flight Maneuvers With an Iced Tailplane

    NASA Technical Reports Server (NTRS)

    VanZante, Judith Foss; Ratvasky, Thomas P.

    1999-01-01

    A detailed analysis of two of the dynamic maneuvers, the pushover and elevator doublet, from the NASA/FAA Tailplane Icing Program are discussed. For this series of flight tests, artificial ice shapes were attached to the leading edge of the horizontal stabilizer of the NASA Lewis Research Center icing aircraft, a DHC-6 Twin Otter. The purpose of these tests was to learn more about ice-contaminated tailplane stall (ICTS), the known cause of 16 accidents resulting in 139 fatalities. The pushover has been employed by the FAA, JAA and Transport Canada for tailplane icing certification. This research analyzes the pushover and reports on the maneuver performance degradation due to ice shape severity and flap deflection. A repeatability analysis suggests tolerances for meeting the required targets of the maneuver. A second maneuver, the elevator doublet, is also studied.

  3. Nonlinear maneuver autopilot for the F-15 aircraft

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Badgett, M. E.; Walker, R. A.

    1989-01-01

    A methodology is described for the development of flight test trajectory control laws based on singular perturbation methodology and nonlinear dynamic modeling. The control design methodology is applied to a detailed nonlinear six degree-of-freedom simulation of the F-15 and results for a level accelerations, pushover/pullup maneuver, zoom and pushover maneuver, excess thrust windup turn, constant thrust windup turn, and a constant dynamic pressure/constant load factor trajectory are presented.

  4. USE OF THE SDO POINTING CONTROLLERS FOR INSTRUMENT CALIBRATION MANEUVERS

    NASA Technical Reports Server (NTRS)

    Vess, Melissa F.; Starin, Scott R.; Morgenstern, Wendy M.

    2005-01-01

    During the science phase of the Solar Dynamics Observatory mission, the three science instruments require periodic instrument calibration maneuvers with a frequency of up to once per month. The command sequences for these maneuvers vary in length from a handful of steps to over 200 steps, and individual steps vary in size from 5 arcsec per step to 22.5 degrees per step. Early in the calibration maneuver development, it was determined that the original attitude sensor complement could not meet the knowledge requirements for the instrument calibration maneuvers in the event of a sensor failure. Because the mission must be single fault tolerant, an attitude determination trade study was undertaken to determine the impact of adding an additional attitude sensor versus developing alternative, potentially complex, methods of performing the maneuvers in the event of a sensor failure. To limit the impact to the science data capture budget, these instrument calibration maneuvers must be performed as quickly as possible while maintaining the tight pointing and knowledge required to obtain valid data during the calibration. To this end, the decision was made to adapt a linear pointing controller by adjusting gains and adding an attitude limiter so that it would be able to slew quickly and still achieve steady pointing once on target. During the analysis of this controller, questions arose about the stability of the controller during slewing maneuvers due to the combination of the integral gain, attitude limit, and actuator saturation. Analysis was performed and a method for disabling the integral action while slewing was incorporated to ensure stability. A high fidelity simulation is used to simulate the various instrument calibration maneuvers.

  5. Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the forward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). This ASMU exerperiment is being done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

  6. Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the foreward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). This ASMU exerperiment is being done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

  7. Spontaneous splenic rupture during Pringle maneuver in liver surgery.

    PubMed

    van Buijtenen, Jesse M; Lamme, Bas; Hesselink, Erik J

    2010-06-27

    During liver resection clamping of the hepato-duodenal ligament (the Pringle maneuver) is performed to reduce intraoperative blood-loss. During this maneuver acute portal hypertension may lead to spontaneous splenic rupture requiring rapid splenectomy in order to control blood loss. We present 2 case of patients with hemorrhage from the spleen during clamping for liver surgery. A review of the literature with an emphasis on the pathophysiology of splenic hemorrhage is presented. PMID:21161004

  8. Optimal terminal maneuver for a cooperative impulsive rendezvous

    NASA Technical Reports Server (NTRS)

    Prussing, John E.; Conway, Bruce A.

    1989-01-01

    An optimal terminal maneuver is presently defined for the cooperative impulsive rendezvous of two spacecraft, in which each vehicle is capable of furnishing all or a part of the velocity change required for the rendezvous. In this maneuver, the final masses of the two vehicles are maximized in a fashion that is equivalent to minimum total propellant consumption. If neither propellant mass fraction constraint is active, one vehicle will supply all of the required velocity change.

  9. Study of stability of large maneuvers of airplanes

    NASA Technical Reports Server (NTRS)

    Haddad, E. K.

    1974-01-01

    A predictive method of nonlinear system analysis is used to investigate airplane stability and dynamic response during rolling maneuvers. The maneuver roll-rate is not assumed to be constant, and the airplane motion is represented by a set of coupled nonlinear differential equations. The general rolling maneuver is kinematically specified by its roll-rate variation p(t). A method for relating the airplane dynamic response to p(t) is developed. The method provides analytical expressions for the motion variables in terms of the maneuver descriptor p(t). A parameterized family of rolling maneuvers is considered, for which the method is used to predict specific dynamic response information, such as the dependence of the peak angle-of-attack excursion on the maneuver parameters. The stability and motion of the airplane in response to an arbitrary actuation of aileron input is considered. Analytical expressions relating motion variables to aileron input are obtained. Explicit analytical bounds on the motion variables are derived. A stability criterion which guarantees nondivergence of motion in response to aileron actuation is presented.

  10. Maneuver Design and Calibration for the Genesis Spacecraft

    NASA Technical Reports Server (NTRS)

    Williams, Kenneth E.; Hong, Philip E.; Zietz, Richard P.; Han, Don

    2000-01-01

    Genesis is the fifth mission selected as part of NASA's Discovery Program. The objective of Genesis is to collect solar wind samples for a period of approximately two years while in a halo orbit about the Earth-Sun L I point. At the end of this period, the samples are to be returned to a specific recovery point on the Earth for subsequent analysis. This goal has never been attempted before and presents a formidable challenge in terms of mission design and operations, particularly planning and execution of propulsive maneuvers. To achieve a level of cost-effectiveness consistent with a Discovery-class mission, the Genesis spacecraft design was adapted to the maximum extent possible from designs used on earlier missions, such as Mars Global Surveyor (MGS) and Stardust, another sample collection mission. The spacecraft design for Genesis is shown. Spin stabilization was chosen for attitude control, in lieu of three-axis stabilization, with neither reaction wheels nor accelerometers included. This precludes closed-loop control of propulsive maneuvers and implies that any attitude changes, including spin changes and precessions, will behave like translational propulsive maneuvers and affect the spacecraft trajectory. Moreover, to minimize contamination risk to the samples collected, all thrusters were placed on the side opposite the sample collection canister. The orientation and characteristics of thrusters are indicated. For large maneuvers (>2.5 m/s), two 5 lbf thrusters will be used for delta v, with precession to the burn attitude, followed by spin-up from 1.6 to 10 rpm before the burn and spin down to 1.6 rpm afterwards, then precession back to the original spin attitude. For small maneuvers (<2.5 m/s), no spin change is needed and four 0.2 lbf thrusters are used for Av. Single or double 360 deg. precession changes are required whenever the desired delta v falls inside the two-way turn circle (about 0.4 m/s) based on the mass properties, spin rate and lever arm

  11. Optimal diving maneuver strategy considering guidance accuracy for hypersonic vehicle

    NASA Astrophysics Data System (ADS)

    Zhu, Jianwen; Liu, Luhua; Tang, Guojian; Bao, Weimin

    2014-11-01

    An optimal maneuver strategy considering terminal guidance accuracy for hypersonic vehicle in dive phase is investigated in this paper. First, it derives the complete three-dimensional nonlinear coupled motion equation without any approximations based on diving relative motion relationship directly, and converts it into linear decoupled state space equation with the same relative degree by feedback linearization. Second, the diving guidance law is designed based on the decoupled equation to meet the terminal impact point and falling angle constraints. In order to further improve the interception capability, it constructs maneuver control model through adding maneuver control item to the guidance law. Then, an integrated performance index consisting of maximum line-of-sight angle rate and minimum energy consumption is designed, and optimal control is employed to obtain optimal maneuver strategy when the encounter time is determined and undetermined, respectively. Furthermore, the performance index and suboptimal strategy are reconstructed to deal with the control capability constraint and the serous influence on terminal guidance accuracy caused by maneuvering flight. Finally, the approach is tested using the Common Aero Vehicle-H model. Simulation results demonstrate that the proposed strategy can achieve high precision guidance and effective maneuver at the same time, and the indices are also optimized.

  12. Automated maneuver planning using a fuzzy logic algorithm

    NASA Technical Reports Server (NTRS)

    Conway, D.; Sperling, R.; Folta, D.; Richon, K.; Defazio, R.

    1994-01-01

    Spacecraft orbital control requires intensive interaction between the analyst and the system used to model the spacecraft trajectory. For orbits with right mission constraints and a large number of maneuvers, this interaction is difficult or expensive to accomplish in a timely manner. Some automation of maneuver planning can reduce these difficulties for maneuver-intensive missions. One approach to this automation is to use fuzzy logic in the control mechanism. Such a prototype system currently under development is discussed. The Tropical Rainfall Measurement Mission (TRMM) is one of several missions that could benefit from automated maneuver planning. TRMM is scheduled for launch in August 1997. The spacecraft is to be maintained in a 350-km circular orbit throughout the 3-year lifetime of the mission, with very small variations in this orbit allowed. Since solar maximum will occur as early as 1999, the solar activity during the TRMM mission will be increasing. The increasing solar activity will result in orbital maneuvers being performed as often as every other day. The results of automated maneuver planning for the TRMM mission will be presented to demonstrate the prototype of the fuzzy logic tool.

  13. Operational Experiences in Planning and Reconstructing Aqua Inclination Maneuvers

    NASA Technical Reports Server (NTRS)

    Rand, David; Reilly, Jacqueline; Schiff, Conrad

    2004-01-01

    As the lead satellite in NASA's growing Earth Observing System (EOS) PM constellation, it is increasingly critical that Aqua maintain its various orbit requirements. The two of interest for this paper are maintaining an orbit inclination that provides for a consistent mean local time and a semi-major Axis (SMA) that allows for ground track repeatability. Maneuvers to adjust the orbit inclination involve several flight dynamics constraints and complexities which make planning such maneuvers challenging. In particular, coupling between the orbital and attitude degrees of freedom lead to changes in SMA when changes in inclination are effected. A long term mission mean local time trend analysis was performed in order to determine the size and placement of the required inclination maneuvers. Following this analysis, detailed modeling of each burn and its Various segments was performed to determine its effects on the immediate orbit state. Data gathered from an inclination slew test of the spacecraft and first inclination maneuver uncovered discrepancies in the modeling method that were investigated and resolved. The new modeling techniques were applied and validated during the second spacecraft inclination maneuver. These improvements should position Aqua to successfully complete a series of inclination maneuvers in the fall of 2004. The following paper presents the events and results related

  14. AH-1S communication switch integration program

    NASA Technical Reports Server (NTRS)

    Haworth, Loran; Szoboszlay, Zoltan; Shively, Robert; Bick, Frank J.

    1989-01-01

    The C-6533/ARC communication system as installed on the test AH-1E Cobra helicopter was modified to allow discrete radio selection of all aircraft radios at the cyclic radio/intercommunication system switch. The current Cobra-fleet use of the C-6533 system is cumbersome, particularly during low-altitude operations. Operationally, the current system C-6533 configuration and design requires the pilot to estimate when he can safely remove his hand from an active flight control to select radios during low-altitude flight. The pilot must then physically remove his hand from the flight control, look inside the cockpit to select and verify the radio selection and then effect the selected radio transmission by activating the radio/ICS switch on the cyclic. This condition is potentially hazardous, especially during low-level flight at night in degraded weather. To improve pilot performance, communications effectiveness, and safety, manprint principles were utilized in the selection of a design modification. The modified C-6533 design was kept as basic as possible for potential Cobra-fleet modification. The communications system was modified and the design was subsequently flight-tested by the U.S. Army Aeroflightdynamics Directorate and NASA at the NASA Ames Research Center, Mountain View, California. The design modification enables the Cobra pilot to maintain hands-on flight controls while selecting radios during nap-of-the-Earth (NOE) flight without looking inside the cockpit which resulted in reduced pilot workload ratings, better pilot handling quality ratings and increased flight safety for the NOE flight environment.

  15. Cerebral hemodynamics during graded Valsalva maneuvers

    PubMed Central

    Perry, Blake G.; Cotter, James D.; Mejuto, Gaizka; Mündel, Toby; Lucas, Samuel J. E.

    2014-01-01

    The Valsalva maneuver (VM) produces large and abrupt changes in mean arterial pressure (MAP) that challenge cerebral blood flow and oxygenation. We examined the effect of VM intensity on middle cerebral artery blood velocity (MCAv) and cortical oxygenation responses during (phases I–III) and following (phase IV) a VM. Healthy participants (n = 20 mean ± SD: 27 ± 7 years) completed 30 and 90% of their maximal VM mouth pressure for 10 s (order randomized) whilst standing. Beat-to-beat MCAv, cerebral oxygenation (NIRS) and MAP across the different phases of the VM are reported as the difference from standing baseline. There were significant interaction (phase * intensity) effects for MCAv, total oxygenation index (TOI) and MAP (all P < 0.01). MCAv decreased during phases II and III (P < 0.01), with the greatest decrease during phase III (−5 ± 8 and −19 ± 15 cm·s−1 for 30 and 90% VM, respectively). This pattern was also evident in TOI (phase III: −1 ± 1 and −5 ± 4%, both P < 0.05). Phase IV increased MCAv (22 ± 15 and 34 ± 23 cm·s−1), MAP (15 ± 14 and 24 ± 17 mm Hg) and TOI (5 ± 6 and 7 ± 5%) relative to baseline (all P < 0.05). Cerebral autoregulation, indexed, as the %MCAv/%MAP ratio, showed a phase effect only (P < 0.001), with the least regulation during phase IV (2.4 ± 3.0 and 3.2 ± 2.9). These data illustrate that an intense VM profoundly affects cerebral hemodynamics, with a reactive hyperemia occurring during phase IV following modest ischemia during phases II and III. PMID:25309449

  16. Rituximab therapy in nephrotic syndrome due to AH amyloidosis.

    PubMed

    Katoh, Nagaaki; Matsuda, Masayuki; Miyazaki, Daigo; Gono, Takahisa; Yazaki, Masahide; Ikeda, Shu-Ichi

    2009-01-01

    We report a patient with AH amyloidosis associated with lymphoplasmacytic leukemia that has remained in a stable state with a nephrotic syndrome for 17 months since the commencement of cyclic rituximab therapy aimed at suppression of pathogenetic gamma heavy chains. Free light chains in serum and CD20-positive cells in peripheral blood were useful as hematological markers in the patient. Rituximab might be a potent therapeutic option for AH amyloidosis associated with a B-cell lymphoproliferative disorder. PMID:19590993

  17. An Overview of Suomi NPP VIIRS Calibration Maneuvers

    NASA Technical Reports Server (NTRS)

    Butler, James J.; Xiong, Xiaoxiong; Barnes, Robert A.; Patt, Frederick S.; Sun, Junqiang; Chiang, Kwofu

    2012-01-01

    The first Visible Infrared Imager Radiometer Suite (VIIRS) instrument was successfully launched on-board the Suomi National Polar-orbiting Partnership (SNPP) spacecraft on October 28, 2011. Suomi NPP VIIRS observations are made in 22 spectral bands, from the visible (VIS) to the long-wave infrared (LWIR), and are used to produce 22 Environmental Data Records (EDRs) with a broad range of scientific applications. The quality of these VIIRS EDRs strongly depends on the quality of its calibrated and geo-located Sensor Date Records (SDRs). Built with a strong heritage to the NASA's EOS MODerate resolution Imaging Spectroradiometer (MODIS) instrument, the VIIRS is calibrated on-orbit using a similar set of on-board calibrators (OBC), including a solar diffuser (SD) and solar diffuser stability monitor (SDSM) system for the reflective solar bands (RSB) and a blackbody (BB) for the thermal emissive bands (TEB). On-orbit maneuvers of the SNPP spacecraft provide additional calibration and characterization data from the VIIRS instrument which cannot be obtained pre-launch and are required to produce the highest quality SDRs. These include multi-orbit yaw maneuvers for the characterization of SD and SDSM screen transmission, quasi-monthly roll maneuvers to acquire lunar observations to track sensor degradation in the visible through shortwave infrared, and a driven pitch-over maneuver to acquire multiple scans of deep space to determine TEB response versus scan angle (RVS). This paper pro-vides an overview of these three SNPP calibration maneuvers. Discussions are focused on their potential calibration and science benefits, pre-launch planning activities, and on-orbit scheduling and implementation strategies. Results from calibration maneuvers performed during the Intensive Calibration and Validation (ICV) period for the VIIRS sensor are illustrated. Also presented in this paper are lessons learned regarding the implementation of calibration spacecraft maneuvers on follow

  18. Using Mean Orbit Period in Mars Reconnaissance Orbiter Maneuver Design

    NASA Technical Reports Server (NTRS)

    Chung, Min-Kun J.; Menon, Premkumar R.; Wagner, Sean V.; Williams, Jessica L.

    2014-01-01

    Mars Reconnaissance Orbiter (MRO) has provided communication relays for a number of Mars spacecraft. In 2016 MRO is expected to support a relay for NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) spacecraft. In addition, support may be needed by another mission, ESA's ExoMars EDL Demonstrator Module's (EDM), only 21 days after the InSight coverage. The close proximity of these two events presents a unique challenge to a conventional orbit synchronization maneuver where one deterministic maneuver is executed prior to each relay. Since the two events are close together and the difference in required phasing between InSight and EDM may be up to half an orbit (yielding a large execution error), the downtrack timing error can increase rapidly at the EDM encounter. Thus, a new maneuver strategy that does not require a deterministic maneuver in-between the two events (with only a small statistical cleanup) is proposed in the paper. This proposed strategy rests heavily on the stability of the mean orbital period. The ability to search and set the specified mean period is fundamental in the proposed maneuver design as well as in understanding the scope of the problem. The proposed strategy is explained and its result is used to understand and solve the problem in the flight operations environment.

  19. Bench-to-bedside review: Recruitment and recruiting maneuvers.

    PubMed

    Lapinsky, Stephen E; Mehta, Sangeeta

    2005-02-01

    In patients with acute respiratory distress syndrome (ARDS), the lung comprises areas of aeration and areas of alveolar collapse, the latter producing intrapulmonary shunt and hypoxemia. The currently suggested strategy of ventilation with low lung volumes can aggravate lung collapse and potentially produce lung injury through shear stress at the interface between aerated and collapsed lung, and as a result of repetitive opening and closing of alveoli. An 'open lung strategy' focused on alveolar patency has therefore been recommended. While positive end-expiratory pressure prevents alveolar collapse, recruitment maneuvers can be used to achieve alveolar recruitment. Various recruitment maneuvers exist, including sustained inflation to high pressures, intermittent sighs, and stepwise increases in positive end-expiratory pressure or peak inspiratory pressure. In animal studies, recruitment maneuvers clearly reverse the derecruitment associated with low tidal volume ventilation, improve gas exchange, and reduce lung injury. Data regarding the use of recruitment maneuvers in patients with ARDS show mixed results, with increased efficacy in those with short duration of ARDS, good compliance of the chest wall, and in extrapulmonary ARDS. In this review we discuss the pathophysiologic basis for the use of recruitment maneuvers and recent evidence, as well as the practical application of the technique. PMID:15693985

  20. Investigation of piloting aids for manual control of hypersonic maneuvers

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Phillips, Michael R.; Person, Lee H., Jr.

    1995-01-01

    An investigation of piloting aids designed to provide precise maneuver control for an air-breathing hypersonic vehicle is described. Stringent constraints and nonintuitive high-speed flight effects associated with maneuvering in the hypersonic regime raise the question of whether manual control of such a vehicle should even be considered. The objectives of this research were to determine the extent of manual control that is desirable for a vehicle maneuvering in this regime and to identify the form of aids that must be supplied to the pilot to make such control feasible. A piloted real-time motion-based simulation of a hypersonic vehicle concept was used for this study, and the investigation focused on a single representative cruise turn maneuver. Piloting aids, which consisted of an auto throttle, throttle director, autopilot, flight director, and two head-up display configurations, were developed and evaluated. Two longitudinal control response types consisting of a rate-command/attitude-hold system and a load factor-rate/load-factor-hold system were also compared. The complete set of piloting aids, which consisted of the autothrottle, throttle director, and flight director, improved the average Cooper-Harper flying qualities ratings from 8 to 2.6, even though identical inner-loop stability and control augmentation was provided in all cases. The flight director was determined to be the most critical of these aids, and the cruise turn maneuver was unachievable to adequate performance specifications in the absence of this flight director.

  1. Maneuver Planning for Conjunction Risk Mitigation with Ground-track Control Requirements

    NASA Technical Reports Server (NTRS)

    McKinley, David

    2008-01-01

    The planning of conjunction Risk Mitigation Maneuvers (RMM) in the presence of ground-track control requirements is analyzed. Past RMM planning efforts on the Aqua, Aura, and Terra spacecraft have demonstrated that only small maneuvers are available when ground-track control requirements are maintained. Assuming small maneuvers, analytical expressions for the effect of a given maneuver on conjunction geometry are derived. The analytical expressions are used to generate a large trade space for initial RMM design. This trade space represents a significant improvement in initial maneuver planning over existing methods that employ high fidelity maneuver models and propagation.

  2. How to Maneuver Around in Eccentricity Vector Space

    NASA Technical Reports Server (NTRS)

    Sweetser, Theodore H.

    2010-01-01

    The GRAIL mission to the Moon will be the first time that two separate robotic orbiters will be placed into formation in orbit around a body other than Earth. The need to design an efficient series of maneuvers to shape the orbits and phasing of the two orbiters after arrival presents a significant challenge to mission designers. This paper presents a simple geometric method for relating in-plane impulsive maneuvers to changes in the eccentricity vector, which determines the shape and orientation of an orbit in the orbit plane. Examples then show how such maneuvers can accommodate desired changes to other orbital elements such as period, incination, and longitude of the ascending node.

  3. On spacecraft maneuvers control subject to propellant engine modes.

    PubMed

    Mazinan, A H

    2015-09-01

    The paper attempts to address a new control approach to spacecraft maneuvers based upon the modes of propellant engine. A realization of control strategy is now presented in engine on mode (high thrusts as well as further low thrusts), which is related to small angle maneuvers and engine off mode (specified low thrusts), which is also related to large angle maneuvers. There is currently a coarse-fine tuning in engine on mode. It is shown that the process of handling the angular velocities are finalized via rate feedback system in engine modes, where the angular rotations are controlled through quaternion based control (QBCL)strategy in engine off mode and these ones are also controlled through an optimum PID (OPIDH) strategy in engine on mode. PMID:26117285

  4. Operational Challenges In TDRS Post-Maneuver Orbit Determination

    NASA Technical Reports Server (NTRS)

    Laing, Jason; Myers, Jessica; Ward, Douglas; Lamb, Rivers

    2015-01-01

    The GSFC Flight Dynamics Facility (FDF) is responsible for daily and post maneuver orbit determination for the Tracking and Data Relay Satellite System (TDRSS). The most stringent requirement for this orbit determination is 75 meters total position accuracy (3-sigma) predicted over one day for Terra's onboard navigation system. To maintain an accurate solution onboard Terra, a solution is generated and provided by the FDF Four hours after a TDRS maneuver. A number of factors present challenges to this support, such as maneuver prediction uncertainty and potentially unreliable tracking from User satellities. Reliable support is provided by comparing an extended Kalman Filter (estimated using ODTK) against a Batch Least Squares system (estimated using GTDS).

  5. The maneuver to release an incarcerated obturator hernia.

    PubMed

    Shigemitsu, Y; Akagi, T; Morimoto, A; Ishio, T; Shiraishi, N; Kitano, S

    2012-12-01

    An obturator hernia occurs through the pelvic obturator canal, a rigid ring made up of the underside of the superior pubic ramus and the obturator fascia. Obturator hernias have been associated with a high mortality due to the difficulty in diagnosis and the population in which it occurs. We examined four patients diagnosed with incarcerated obturator hernia, and showed that the strangulated intestine was not necrotic. We flexed the diseased leg calmly and repeatedly with slight rotation toward the outside and slight adduction toward the inside at supine position. The pain vanished suddenly during this maneuver. After this maneuver, the patients were able to undergo elective surgery after a certain interval. We discuss the possible use of this maneuver to release an incarcerated obturator hernia. PMID:21369820

  6. Quantifying Dragonfly Kinematics During Unsteady Free-Flight Maneuvers

    NASA Astrophysics Data System (ADS)

    Melfi, James; Lin, Huai-Ti; Mischiati, Matteo; Leonardo, Anthony; Wang, Z. Jane

    2012-11-01

    What make dragonflies such interesting fliers are the unsteady high-speed aerial maneuvers they perform. Until recently, the study of dragonflies in mid-flight has been limited to steady-state motions such as hovering and forward flight. In this talk, we report our kinematic analyses of the dragonfly flight recorded in a custom dragonfly arena at HHMI, Janelia Farm. Dragonfly's turning motions often involve all three degrees of freedom about its body axes: yaw, roll, and pitch. We examine the wing kinematics changes associated with different turning maneuvers, and seek the key variables in the wing kinematics that are responsible for each specific maneuver. This work is supported by a grant to ZJW and AL through the visitor program at Janelia Farm, HHMI.

  7. Severe turbulence and maneuvering from airline flight records

    NASA Technical Reports Server (NTRS)

    Wingrove, R. C.; Basch, R. E., Jr.

    1992-01-01

    Digital flight records from reported clear-air turbulence incidents are used to determine winds, to determine maneuver G loads, and to analyze control problems. Severe turbulence is found downwind of mountains and thunderstorms associated with vortices in atmospheric waves. It is also found in strong updrafts above thunderstorm buildups that are not detected by onboard weather radar. An important finding is that there are large maneuvering loads in over half of the reported clear-air turbulence incidents. Maneuvering loads are determined through an analysis of the short-term variations in elevator deflection and aircraft pitch angle. For altitude control in mountain waves the results indicate that small pitch angle changes with proper timing are sufficient to counter the vertical winds. For airspeed control in strong mountain waves, however, there is neither the available thrust nor the quickness in engine response necessary to counter the large and rapid variations in horizontal wind.

  8. Attitude-Control Algorithm for Minimizing Maneuver Execution Errors

    NASA Technical Reports Server (NTRS)

    Acikmese, Behcet

    2008-01-01

    A G-RAC attitude-control algorithm is used to minimize maneuver execution error in a spacecraft with a flexible appendage when said spacecraft must induce translational momentum by firing (in open loop) large thrusters along a desired direction for a given period of time. The controller is dynamic with two integrators and requires measurement of only the angular position and velocity of the spacecraft. The global stability of the closed-loop system is guaranteed without having access to the states describing the dynamics of the appendage and with severe saturation in the available torque. Spacecraft apply open-loop thruster firings to induce a desired translational momentum with an extended appendage. This control algorithm will assist this maneuver by stabilizing the attitude dynamics around a desired orientation, and consequently minimize the maneuver execution errors.

  9. A Maneuvering Flight Noise Model for Helicopter Mission Planning

    NASA Technical Reports Server (NTRS)

    Greenwood, Eric; Rau, Robert; May, Benjamin; Hobbs, Christopher

    2015-01-01

    A new model for estimating the noise radiation during maneuvering flight is developed in this paper. The model applies the Quasi-Static Acoustic Mapping (Q-SAM) method to a database of acoustic spheres generated using the Fundamental Rotorcraft Acoustics Modeling from Experiments (FRAME) technique. A method is developed to generate a realistic flight trajectory from a limited set of waypoints and is used to calculate the quasi-static operating condition and corresponding acoustic sphere for the vehicle throughout the maneuver. By using a previously computed database of acoustic spheres, the acoustic impact of proposed helicopter operations can be rapidly predicted for use in mission-planning. The resulting FRAME-QS model is applied to near-horizon noise measurements collected for the Bell 430 helicopter undergoing transient pitch up and roll maneuvers, with good agreement between the measured data and the FRAME-QS model.

  10. Lethal poisonings with AH-7921 in combination with other substances.

    PubMed

    Karinen, Ritva; Tuv, Silja Skogstad; Rogde, Sidsel; Peres, Mariana Dadalto; Johansen, Unni; Frost, Joachim; Vindenes, Vigdis; Øiestad, Åse Marit Leere

    2014-11-01

    AH-7921 is a synthetic μ-opioid agonist, approximately equipotent with morphine. We report the death of two young individuals after ingestion of AH-7921 in combination with other psychoactive drugs. In the first case a young man died shortly after ingesting Internet drugs. Toxicological analysis of post mortem peripheral blood revealed AH-7921 (0.43 mg/L), 2-FMA (0.0069 mg/L) and 3-MMC (0.0021 mg/L) as well as codeine (0.42 mg/L), codeine-6-glucuronide (0.77 mg/L) and acetaminophen (18.7 mg/L). The second case involved a young female found dead at home. The only positive finding at medicolegal autopsy was needle marks. Toxicological analysis revealed AH-7921 (0.33 mg/L), methoxetamine (MXE) (0.064 mg/L), etizolam (0.27 mg/L), phenazepam (1.33 mg/L), 7-aminonitrazepam (0.043 mg/L), diazepam (0.046 mg/L), nordiazepam (0.073 mg/L), and oxazepam (0.018 mg/L) in blood. In both cases intoxication with AH-7921 in combination with other psychoactive drugs was considered to be the cause of death. PMID:25216892

  11. Maneuver Acoustic Flight Test of the Bell 430 Helicopter

    NASA Technical Reports Server (NTRS)

    Watts, Michael E.; Snider, Royce; Greenwood, Eric; Baden, Joel

    2012-01-01

    A cooperative flight test by NASA, Bell Helicopter and the U.S. Army to characterize the steady state acoustics and measure the maneuver noise of a Bell Helicopter 430 aircraft was accomplished. The test occurred during June/July, 2011 at Eglin Air Force Base, Florida. This test gathered a total of 410 data points over 10 test days and compiled an extensive data base of dynamic maneuver measurements. Three microphone configurations with up to 31 microphones in each configuration were used to acquire acoustic data. Aircraft data included DGPS, aircraft state and rotor state information. This paper provides an overview of the test.

  12. Fuel optimal maneuvers of spacecraft about a circular orbit

    NASA Technical Reports Server (NTRS)

    Carter, T. E.

    1982-01-01

    Fuel optimal maneuvers of spacecraft relative to a body in circular orbit are investigated using a point mass model in which the magnitude of the thrust vector is bounded. All nonsingular optimal maneuvers consist of intervals of full thrust and coast and are found to contain at most seven such intervals in one period. Only four boundary conditions where singular solutions occur are possible. Computer simulation of optimal flight path shapes and switching functions are found for various boundary conditions. Emphasis is placed on the problem of soft rendezvous with a body in circular orbit.

  13. Active Control of Solar Array Dynamics During Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Ross, Brant A.; Woo, Nelson; Kraft, Thomas G.; Blandino, Joseph R.

    2016-01-01

    Recent NASA mission plans require spacecraft to undergo potentially significant maneuvers (or dynamic loading events) with large solar arrays deployed. Therefore there is an increased need to understand and possibly control the nonlinear dynamics in the spacecraft system during such maneuvers. The development of a nonlinear controller is described. The utility of using a nonlinear controller to reduce forces and motion in a solar array wing during a loading event is demonstrated. The result is dramatic reductions in system forces and motion during a 10 second loading event. A motion curve derived from the simulation with the closed loop controller is used to obtain similar benefits with a simpler motion control approach.

  14. Astronaut Alan Bean flies the Astronaut Maneuvering Equipment

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Alan L. Bean, Skylab 3 commander, flies the M509 Astronaut Maneuvering Equipment in the foreward dome area of the Orbital Workshop (OWS) on the space station cluster in Earth orbit. Bean is strapped in to the back-mounted, hand-controlled Automatically Stabilized Maneuvering Unit (ASMU). He is wearing a pressure suit for this run of the M509 experiment, but other ASMU tests are done in shirt sleeves. The dome area where the experiment is conducted is about 22 feet in diameter and 19 feet from top to bottom.

  15. A controller design for multi-body large angle maneuvers

    NASA Technical Reports Server (NTRS)

    Ghaemmaghami, Peiman; Juang, Jer-Nan

    1989-01-01

    Active large angle slewing maneuvers of a multi-body flexible dynamic system are investigated. An appropriate state variable transformation and a feedback linearization technique are employed to transform the dynamics of the nonlinear system to a new state that is more amenable to control design procedures. Closed-loop feedback algorithms are implemented to perform slewing maneuvers, while simultaneously suppressing flexural vibrations of the system. Stability of this class of nonlinear systems is also investigated, whereby a sufficient condition for asymptotic stability of the system is established. Numerical examples are presented to demonstrate the proposed active control algorithms.

  16. NOAA 26.5 Ah LEO characterization test

    NASA Technical Reports Server (NTRS)

    Morrow, G. W.

    1986-01-01

    The General Electric (GE) 26.5 Ah NOAA-G flight nickel-cadmium cells were obtained from RCA-Astro Electronics to undergo performance characterization testing at the Goddard Space Flight Center (GSFC). This lot of cells was manufactured with passivated positive plate, to control nickel structure attack duing active material impregnation, and less electrolyte than normal (less than 3cc/Ah). The cells were tested in a parametric low Earth orbit (LEO) cycling regime that was previously used to test and characterize standard 50 Ah cells. Life cycle testing at the Naval Weapons Support Center (NWSC), in Crane, followed. The results of the test showed nominal performance in comparison with previous test data on the standard 50. Life cycle testing in the NOAA orbital regime is continuing at NWSC.

  17. Evaluation of an expert system for fault detection, isolation, and recovery in the manned maneuvering unit

    NASA Technical Reports Server (NTRS)

    Rushby, John; Crow, Judith

    1990-01-01

    The authors explore issues in the specification, verification, and validation of artificial intelligence (AI) based software, using a prototype fault detection, isolation and recovery (FDIR) system for the Manned Maneuvering Unit (MMU). They use this system as a vehicle for exploring issues in the semantics of C-Language Integrated Production System (CLIPS)-style rule-based languages, the verification of properties relating to safety and reliability, and the static and dynamic analysis of knowledge based systems. This analysis reveals errors and shortcomings in the MMU FDIR system and raises a number of issues concerning software engineering in CLIPs. The authors came to realize that the MMU FDIR system does not conform to conventional definitions of AI software, despite the fact that it was intended and indeed presented as an AI system. The authors discuss this apparent disparity and related questions such as the role of AI techniques in space and aircraft operations and the suitability of CLIPS for critical applications.

  18. Transgenic Overexpression of Aryl Hydrocarbon Receptor Repressor (AhRR) and AhR-Mediated Induction of CYP1A1, Cytokines, and Acute Toxicity

    PubMed Central

    Vogel, Christoph F.A.; Chang, W.L. William; Kado, Sarah; McCulloh, Kelly; Vogel, Helena; Wu, Dalei; Haarmann-Stemmann, Thomas; Yang, GuoXiang; Leung, Patrick S.C.; Matsumura, Fumio; Gershwin, M. Eric

    2016-01-01

    Background: The aryl hydrocarbon receptor repressor (AhRR) is known to repress aryl hydrocarbon receptor (AhR) signaling, but very little is known regarding the role of the AhRR in vivo. Objective: This study tested the role of AhRR in vivo in AhRR overexpressing mice on molecular and toxic end points mediated through a prototypical AhR ligand. Methods: We generated AhRR-transgenic mice (AhRR Tg) based on the genetic background of C57BL/6J wild type (wt) mice. We tested the effect of the prototypical AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the expression of cytochrome P450 (CYP)1A1 and cytokines in various tissues of mice. We next analyzed the infiltration of immune cells in adipose tissue of mice after treatment with TCDD using flow cytometry. Results: AhRR Tg mice express significantly higher levels of AhRR compared to wt mice. Activation of AhR by TCDD caused a significant increase of the inflammatory cytokines Interleukin (IL)-1β, IL-6 and IL-10, and CXCL chemokines in white epididymal adipose tissue from both wt and AhRR Tg mice. However, the expression of IL-1β, CXCL2 and CXCL3 were significantly lower in AhRR Tg versus wt mice following TCDD treatment. Exposure to TCDD caused a rapid accumulation of neutrophils and macrophages in white adipose tissue of wt and AhRR Tg mice. Furthermore we found that male AhRR Tg mice were protected from high-dose TCDD-induced lethality associated with a reduced inflammatory response and liver damage as indicated by lower levels of TCDD-induced alanine aminotransferase and hepatic triglycerides. Females from both wt and AhRR Tg mice were less sensitive than male mice to acute toxicity induced by TCDD. Conclusion: In conclusion, the current study identifies AhRR as a previously uncharacterized regulator of specific inflammatory cytokines, which may protect from acute toxicity induced by TCDD. Citation: Vogel CF, Chang WL, Kado S, McCulloh K, Vogel H, Wu D, Haarmann-Stemmann T, Yang GX, Leung PS, Matsumura F

  19. Reducing Formation-Keeping Maneuver Costs for Formation Flying Satellites in Low-Earth Orbit

    NASA Technical Reports Server (NTRS)

    Hamilton, Nicholas

    2001-01-01

    Several techniques are used to synthesize the formation-keeping control law for a three-satellite formation in low-earth orbit. The objective is to minimize maneuver cost and position tracking error. Initial reductions are found for a one-satellite case by tuning the state-weighting matrix within the linear-quadratic-Gaussian framework. Further savings come from adjusting the maneuver interval. Scenarios examined include cases with and without process noise. These results are then applied to a three-satellite formation. For both the one-satellite and three-satellite cases, increasing the maneuver interval yields a decrease in maneuver cost and an increase in position tracking error. A maneuver interval of 8-10 minutes provides a good trade-off between maneuver cost and position tracking error. An analysis of the closed-loop poles with respect to varying maneuver intervals explains the effectiveness of the chosen maneuver interval.

  20. 14 CFR 23.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factors. 23.337 Section 23.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

  1. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., whichever occurs first, need not be considered. (2) Specified control displacement. A checked maneuver... EC28SE91.033 where— n is the positive load factor at the speed under consideration, and V is the airplane equivalent speed in knots. (ii) A negative pitching acceleration (nose down) is assumed to be...

  2. 14 CFR 25.331 - Symmetric maneuvering conditions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., whichever occurs first, need not be considered. (2) Specified control displacement. A checked maneuver... EC28SE91.033 where— n is the positive load factor at the speed under consideration, and V is the airplane equivalent speed in knots. (ii) A negative pitching acceleration (nose down) is assumed to be...

  3. LOCK, DOG HOUSE, CONTROL STATION, DAM GATE, MANEUVER BOAT No. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    LOCK, DOG HOUSE, CONTROL STATION, DAM GATE, MANEUVER BOAT No. 1, AND DAM. NOTE LOWER LOCK GATE IN FOREGROUND. LOOKING NORTH NORTHEAST. - Illinois Waterway, La Grange Lock and Dam, 3/4 mile south of Country 795N at Illinois River, Versailles, Brown County, IL

  4. Time frequency analysis of sound from a maneuvering rotorcraft

    NASA Astrophysics Data System (ADS)

    Stephenson, James H.; Tinney, Charles E.; Greenwood, Eric; Watts, Michael E.

    2014-10-01

    The acoustic signatures produced by a full-scale, Bell 430 helicopter during steady-level-flight and transient roll-right maneuvers are analyzed by way of time-frequency analysis. The roll-right maneuvers comprise both a medium and a fast roll rate. Data are acquired using a single ground based microphone that are analyzed by way of the Morlet wavelet transform to extract the spectral properties and sound pressure levels as functions of time. The findings show that during maneuvering operations of the helicopter, both the overall sound pressure level and the blade-vortex interaction sound pressure level are greatest when the roll rate of the vehicle is at its maximum. The reduced inflow in the region of the rotor disk where blade-vortex interaction noise originates is determined to be the cause of the increase in noise. A local decrease in inflow reduces the miss distance of the tip vortex and thereby increases the BVI noise signature. Blade loading and advance ratios are also investigated as possible mechanisms for increased sound production, but are shown to be fairly constant throughout the maneuvers.

  5. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Limit maneuvering load factor. 27.337 Section 27.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads §...

  6. 14 CFR 27.337 - Limit maneuvering load factor.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Limit maneuvering load factor. 27.337 Section 27.337 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Flight Loads §...

  7. Normative data on phases of the Valsalva maneuver

    NASA Technical Reports Server (NTRS)

    Denq, J. C.; O'Brien, P. C.; Low, P. A.

    1998-01-01

    The phases of the Valsalva maneuver have well-known pathophysiology, and are used in the evaluation of adrenergic function. Because scant normative data is available, we have evaluated normative data for the Valsalva maneuver in control subjects. The patient, supine, performed the Valsalva maneuver maintaining an expiratory pressure of 40 mm Hg for 15 seconds. We reviewed 188 Valsalva maneuver recordings of normal control subjects, and recordings were excluded if two reproducible recordings were not obtained, or if expiratory pressure was <30 mm Hg or < 10 seconds. One hundred and three recordings were acceptable for analysis; 47 female and 56 male subjects, age in years (mean +/- SD) was 52.2+/-17.3 and 44.8+/-17.3, respectively. The association of expiratory pressure with age (P < 0.001) and gender ( P < 0.001) was complex, expressed as a parabola in both men and women, but resulted in phases I and III that were not significantly different. An increase in age resulted in a progressively more negative phase II_E (P < 0.05) and attenuation of phase II_L (P < 0.01). An increase in supine blood pressure resulted in a significantly more negative phase II_E (P < 0.001) and a lower phase IV. Phase IV is unaffected by age and gender.

  8. 33 CFR 157.445 - Maneuvering performance capability.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Maneuvering performance capability. 157.445 Section 157.445 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Interim Measures...

  9. Transient Structured Distance as a Maneuver in Marital Therapy

    ERIC Educational Resources Information Center

    Greene, Bernard L.; And Others

    1973-01-01

    Experience with 73 cases has shown the value of Transient Structured Distance as a maneuver in marriage therapy. While the TSD is a radical form of intervention with risks of anxiety reactions, homosexual panic, or divorce, it has proved effective with difficult forms of acute or chronic marital disharmony. (Author)

  10. Maneuvering and stability performance of a robotic tuna.

    PubMed

    Anderson, Jamie M; Chhabra, Narender K

    2002-02-01

    The Draper Laboratory Vorticity Control Unmanned Undersea Vehicle (VCUUV) is the first mission-scale, autonomous underwater vehicle that uses vorticity control propulsion and maneuvering. Built as a research platform with which to study the energetics and maneuvering performance of fish-swimming propulsion, the VCUUV is a self-contained free swimming research vehicle which follows the morphology and kinematics of a yellowfin tuna. The forward half of the vehicle is comprised of a rigid hull which houses batteries, electronics, ballast and hydraulic power unit. The aft section is a freely flooded articulated robot tail which is terminated with a lunate caudal fin. Utilizing experimentally optimized body and tail kinematics from the MIT RoboTuna, the VCUUV has demonstrated stable steady swimming speeds up to 1.2 m/sec and aggressive maneuvering trajectories with turning rates up to 75 degrees per second. This paper summarizes the vehicle maneuvering and stability performance observed in field trials and compares the results to predicted performance using theoretical and empirical techniques. PMID:21708700

  11. Performance of Driver-Vehicle in Aborted Lane Change Maneuvers

    NASA Technical Reports Server (NTRS)

    Lee, Allan Y.

    1995-01-01

    A 'lane change crash' is defined as a family of collisions that occurred when a driver attempts to change lane and strikes or is struck by a vehicle in the adjacent lane. One type of maneuver that is commonly used to avert a lane change crash involved aborting the intended lane change, and returning the vehicle to the original lane of the subject vehicle.

  12. Vibration suppression of fixed-time jib crane maneuvers

    SciTech Connect

    Parker, G.G.; Petterson, B.; Dohrmann, C.R.; Robinett, R.D.

    1995-02-01

    A jib crane consists of a pendulum-like end line attached to a rotatable jib. Within this general category of cranes there exist devices with multiple degrees of freedom including variable load-line length and variable jib length. These cranes are commonly used for construction and transportation applications. Point-to-point payload maneuvers using jib cranes are performed so as not to excite the spherical pendulum modes of their cable and payload assemblies. Typically, these pendulum modes, although time-varying, exhibit low frequencies. The resulting maneuvers are therefore performed slowly, contributing to high construction and transportation costs. The crane considered here consists of a spherical pendulum attached to a rigid jib. The other end of the jib is attached to a direct drive motor for generating rotational motion. A general approach is presented for determining the open-loop trajectories for the jib rotation for accomplishing fixed-time, point-to-point, residual oscillation free, symmetric maneuvers. These residual oscillation free trajectories purposely excite the pendulum modes in such a way that at the end of the maneuver the oscillatory degrees of freedom are quiescent. Simulation results are presented with experimental verification.

  13. Time-optical spinup maneuvers of flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Singh, G.; Kabamba, P. T.; Mcclamroch, N. H.

    1990-01-01

    Attitude controllers for spacecraft have been based on the assumption that the bodies being controlled are rigid. Future spacecraft, however, may be quite flexible. Many applications require spinning up/down these vehicles. In this work the minimum time control of these maneuvers is considered. The time-optimal control is shown to possess an important symmetry property. Taking advantage of this property, the necessary and sufficient conditions for optimality are transformed into a system of nonlinear algebraic equations in the control switching times during one half of the maneuver, the maneuver time, and the costates at the mid-maneuver time. These equations can be solved using a homotopy approach. Control spillover measures are introduced and upper bounds on these measures are obtained. For a special case these upper bounds can be expressed in closed form for an infinite dimensional evaluation model. Rotational stiffening effects are ignored in the optimal control analysis. Based on a heuristic argument a simple condition is given which justifies the omission of these nonlinear effects. This condition is validated by numerical simulation.

  14. Detail view of a starboard Orbiter Maneuvering and Reaction Control ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of a starboard Orbiter Maneuvering and Reaction Control Systems pod, removed from the orbiter and in it's carrier/transport vehicle at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  15. Astronaut Bruce McCandless tests astronaut maneuvering unit

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Bruce McCandless II, backup pilot for Skylab 2, tests the balance and control of an astronaut maneuvering unit (AMU) test model at Martin Marietta Corporation's Denver division. The jet-powered backpack can fly for 30 minutes and can be worn over normal clothing or space suit.

  16. Characterizing GPS Block IIA Shadow and Post-Shadow Maneuvers

    NASA Astrophysics Data System (ADS)

    Weiss, J.; Bar-Sever, Y.; Bertiger, W.; Desai, S.; Haines, B.; Harvey, N.; Sibthorpe, A.

    2012-04-01

    We characterize GPS Block IIA shadow and post-shadow maneuvers by way of "reverse" precise point positioning (PPP). This technique takes advantage of the non-zero antenna phase center offset, representing the vector from the satellites' center of gravity (CG) to the antenna phase center, to estimate the spacecraft yaw attitude. We begin with a standard GIPSY-based precise orbit determination (POD) solution for the GPS constellation, and use the ground station troposphere, clock, and position estimates, as well as the reduced-dynamic GPS orbit solution as input to a follow-up estimation where the spacecraft body-fixed x, y, and z antenna phase center offsets relative the CG are estimated as unconstrained stochastic white noise parameters every 30 seconds. These estimates directly provide yaw attitude because the spacecraft attitude in the follow-up estimation is set to follow the "velocity frame," where the body-fixed z points towards the Earth, x points along the velocity vector, and y completes the right-handed coordinate system. The estimated antenna offsets absorb errors in the velocity frame attitude model, which does not perform noon and shadow maneuvers, and in turn directly measure spacecraft yaw attitude. In this presentation we utilize the outlined approach to characterize both shadow and post-shadow maneuvers of the GPS Block IIA spacecraft over a period of three years. We fit linear models to the yaw angle estimates during shadow (when the spacecraft traverses umbra) and compare the resulting yaw rate to estimates from standard POD solutions. We particularly focus on changes in yaw rate over time, and on using estimates from reverse PPP to improve nominal yaw rate values. We additionally characterize post-shadow maneuvers for which data are typically removed in POD solutions because the direction and duration of the yaw maneuver to recover nominal attitude are not straightforward to model. We analyze post-shadow maneuvers in terms of yaw angle versus

  17. 47 CFR 80.1183 - Remote control for maneuvering or navigation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Remote control for maneuvering or navigation... Communications § 80.1183 Remote control for maneuvering or navigation. (a) An on-board station may be used for remote control of maneuvering or navigation control systems aboard the same ship or, where that ship...

  18. 47 CFR 80.1183 - Remote control for maneuvering or navigation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Remote control for maneuvering or navigation... Communications § 80.1183 Remote control for maneuvering or navigation. (a) An on-board station may be used for remote control of maneuvering or navigation control systems aboard the same ship or, where that ship...

  19. 47 CFR 80.1183 - Remote control for maneuvering or navigation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Remote control for maneuvering or navigation... Communications § 80.1183 Remote control for maneuvering or navigation. (a) An on-board station may be used for remote control of maneuvering or navigation control systems aboard the same ship or, where that ship...

  20. 47 CFR 80.1183 - Remote control for maneuvering or navigation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Remote control for maneuvering or navigation... Communications § 80.1183 Remote control for maneuvering or navigation. (a) An on-board station may be used for remote control of maneuvering or navigation control systems aboard the same ship or, where that ship...

  1. 47 CFR 80.1183 - Remote control for maneuvering or navigation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Remote control for maneuvering or navigation... Communications § 80.1183 Remote control for maneuvering or navigation. (a) An on-board station may be used for remote control of maneuvering or navigation control systems aboard the same ship or, where that ship...

  2. Maneuver Analysis and Targeting Strategy for the Stardust Re-Entry Capsule

    NASA Technical Reports Server (NTRS)

    Helfrich, Clifford E.; Bhat, Ram; Kangas, Julie; Wilson, Roby; Wong, Mau; Potts, Chris; Williams, Ken

    2006-01-01

    Stardust employed biased maneuvers to limit turns and minimize execution errors. Biased maneuvers also addressed planetary protection and safety issues. Stardust utilized a fixed-direction burn for the final maneuver to match the prevailing attitude so no turns were needed. Performance of the final burn was calibrated in flight.

  3. Orbit determination across unknown maneuvers using the essential Thrust-Fourier-Coefficients

    NASA Astrophysics Data System (ADS)

    Ko, Hyun Chul; Scheeres, Daniel J.

    2016-01-01

    Any maneuver performed by a satellite transitioning between two arbitrary orbital states can be represented as an equivalent maneuver involving Thrust-Fourier-Coefficients (TFCs). With a selected TFC set as a basis, a thrust acceleration can be constructed to interpolate two unconnected states across an unknown maneuver. This representation technique with TFCs enables us to facilitate the analytical propagation of uncertainties of the satellite state. This approach allows for the usage of existing pre-maneuver orbit estimation to compute the orbit solution after the unknown maneuver. In this paper, we applied this approach to orbit determination (OD) problems across unknown maneuvers by appending different combinations of TFCs to the state vector in the batch filter. The aim is to investigate how different maneuver representations with different TFC sets affect the OD solution across unknown maneuvers. Simulation results show that each TFC set provides different representations of the unknown perturbing acceleration, which yields varying magnitudes of delta velocity for a given maneuver. However, OD solutions across unknown maneuvers using different TFC sets display equivalent performance over the post-maneuver arc as long as those TFC sets are capable of generating the apparent secular motion caused by a given unknown maneuver.

  4. Maneuvering hydrodynamics of fish and small underwater vehicles.

    PubMed

    Bandyopadhyay, Promode R

    2002-02-01

    The understanding of fish maneuvering and its application to underwater rigid bodies are considered. The goal is to gain insight into stealth. The recent progress made in NUWC is reviewed. Fish morphology suggests that control fins for maneuverability have unique scalar relationships irrespective of their speed type. Maneuvering experiments are carried out with fish that are fast yet maneuverable. The gap in maneuverability between fish and small underwater vehicles is quantified. The hydrodynamics of a dorsal fin based brisk maneuvering device and a dual flapping foil device, as applied to rigid cylindrical bodies, are described. The role of pectoral wings in maneuvering and station keeping near surface waves is discussed. A pendulum model of dolphin swimming is presented to show that body length and tail flapping frequency are related. For nearly neutrally buoyant bodies, Froude number and maneuverability are related. Analysis of measurements indicates that the Strouhal number of dolphins is a constant. The mechanism of discrete and deterministic vortex shedding from oscillating control surfaces has the property of large amplitude unsteady forcing and an exquisite phase dependence, which makes it inherently amenable to active control for precision maneuvering. Theoretical control studies are carried out to demonstrate the feasibility of maneuverability of biologically inspired bodies under surface waves. The application of fish hydrodynamics to the silencing of propulsors is considered. Two strategies for the reduction of radiated noise are developed. The effects of a reduction of rotational rate are modeled. The active cambering of blades made of digitally programmable artificial muscles, and their thrust enhancement, are demonstrated. Next, wake momentum filling is carried out by artificial muscles at the trailing edge of a stator blade of an upstream stator propulsor, and articulating them like a fish tail. A reduction of radiated noise, called blade tonals

  5. CCD Photometric Study and Period Investigation of AH Tauri

    NASA Astrophysics Data System (ADS)

    Xiang, Fu-Yuan; Xiao, Ting-Yu; Yu, Yun-Xia

    2015-07-01

    In this paper, we present new CCD photometric observations of AH Tauri in the R band observed in 2006 at the Yunnan Observatory. Two new times of light minima were derived from these observations. We modeled the light curves using the 2003 version of the Wilson-Devinney program. The results show that the variations of the light curves can be expained by a cool spot on the primary star. The fill-out factor is about 6.6%, indicating that AH Tauri is a shallow-contact system. The mass ratio was determined to be about 0.505. In addition, the orbital period variations of AH Tauri were investigated based on all of the photoelectric and CCD light minimum times, including our two new data. It was found that the orbital period exhibits a possible periodic variation with a period of {P}{mod}=54.62\\(+/- 0.20) years and a secular period decrease of {dP}/{dt}=-(1.823+/- 0.215)× {10}-7 {days} {{yr}}-1. Since AH Tauri is an overcontact solar-like system, we discuss three mechanisms of the mass transfer, the light-time effect of the third body, and magnetic activity responsible for the orbital period changes.

  6. PESTICIDE TRADE NAMES AND THEIR ACTIVE INGREDIENTS IN THE AHS

    EPA Science Inventory

    The detailed information on the use of specific pesticides is a major strength of exposure assessment conducted for the Agricultural Health Study (AHS). During the enrollment interviews, a check list was used to collect information on the frequency and duration of use for 28 p...

  7. Comparative epidemiology of human infections with avian influenza A(H7N9) and A(H5N1) viruses in China

    PubMed Central

    Cowling, Benjamin J.; Jin, Lianmei; Lau, Eric H. Y.; Liao, Qiaohong; Wu, Peng; Jiang, Hui; Tsang, Tim K.; Zheng, Jiandong; Fang, Vicky J.; Chang, Zhaorui; Ni, Michael Y.; Zhang, Qian; Ip, Dennis K. M.; Yu, Jianxing; Li, Yu; Wang, Liping; Tu, Wenxiao; Meng, Ling; Wu, Joseph T.; Luo, Huiming; Li, Qun; Shu, Yuelong; Li, Zhongjie; Feng, Zijian; Yang, Weizhong; Wang, Yu; Leung, Gabriel M.; Yu, Hongjie

    2013-01-01

    Background The novel influenza A(H7N9) virus recently emerged, while influenza A(H5N1) virus has infected humans since 2003 in mainland China. Both infections are thought to be predominantly zoonotic. We compared the epidemiologic characteristics of the complete series of laboratory-confirmed cases of both viruses in mainland China to date. Methods An integrated database was constructed with information on demographic, epidemiological, and clinical variables of laboratory-confirmed A(H7N9) and A(H5N1) cases that were reported to the Chinese Center for Disease Control and Prevention up to May 24, 2013. We described disease occurrence by age, sex and geography and estimated key epidemiologic parameters. Findings Among 130 and 43 patients with confirmed A(H7N9) and A(H5N1) respectively, the median ages were 62y and 26y. In urban areas, 74% of cases of both viruses were male whereas in rural areas the proportions were 62% for A(H7N9) and 33% for A(H5N1). Among cases of A(H7N9) and A(H5N1), 75% and 71% reported recent exposure to poultry. The mean incubation periods of A(H7N9) and A(H5N1) were 3.1 and 3.3 days, respectively. On average, 21 and 18 contacts were traced for each A(H7N9) case in urban and rural areas respectively; compared to 90 and 63 for A(H5N1). The hospitalization fatality risk was 35% (95% CI: 25%, 44%) for A(H7N9) and 70% (95% CI: 56%, 83%) for A(H5N1). Interpretation The sex ratios in urban compared to rural cases are consistent with poultry exposure driving the risk of infection. However the difference in susceptibility to serious illness with the two different viruses remains unexplained, given that most A(H7N9) cases were in older adults while most A(H5N1) cases were in younger individuals. Funding Ministry of Science and Technology, China; Research Fund for the Control of Infectious Disease and University Grants Committee, Hong Kong Special Administrative Region, China; and the US National Institutes of Health. PMID:23803488

  8. Maneuver Performance Assessment of the Cassini Spacecraft Through Execution-Error Modeling and Analysis

    NASA Technical Reports Server (NTRS)

    Wagner, Sean

    2014-01-01

    The Cassini spacecraft has executed nearly 300 maneuvers since 1997, providing ample data for execution-error model updates. With maneuvers through 2017, opportunities remain to improve on the models and remove biases identified in maneuver executions. This manuscript focuses on how execution-error models can be used to judge maneuver performance, while providing a means for detecting performance degradation. Additionally, this paper describes Cassini's execution-error model updates in August 2012. An assessment of Cassini's maneuver performance through OTM-368 on January 5, 2014 is also presented.

  9. Cassini Maneuver Experience for the Fourth Year of the Solstice Mission

    NASA Technical Reports Server (NTRS)

    Vaquero, Mar; Hahn, Yungsun; Stumpf, Paul; Valerino, Powtawche; Wagner, Sean; Wong, Mau

    2014-01-01

    After sixteen years of successful mission operations and invaluable scientific discoveries, the Cassini orbiter continues to tour Saturn on the most complex gravity-assist trajectory ever flown. To ensure that the end-of-mission target of September 2017 is achieved, propellant preservation is highly prioritized over maneuver cycle minimization. Thus, the maneuver decision process, which includes determining whether a maneuver is performed or canceled, designing a targeting strategy and selecting the engine for execution, is being continuously re-evaluated. This paper summarizes the maneuver experience throughout the fourth year of the Solstice Mission highlighting 27 maneuvers targeted to nine Titan flybys.

  10. A geostationary longitude acquisition planning algorithm. [for maneuver planning of geosynchronous satellites

    NASA Technical Reports Server (NTRS)

    Petruzzo, C. J.; Bryant, W. C., Jr.; Nickerson, K. G.

    1977-01-01

    The paper is concerned with the phase of the geosynchronous mission termed station acquisition, which involves the maneuvering of a spacecraft to its geostationary longitude by means of the spacecraft propulsion system. An algorithm which assists in maneuver planning is described, and examples of its use are presented. The algorithm can be applied when sequences of more than three maneuvers are to be expected. While, in general, three maneuvers are sufficient to achieve the desired end conditions when orbital mechanics are the only consideration, operational considerations may add constraints resulting in an increased number of maneuvers required.

  11. Orbit Determination and Maneuver Detection Using Event Representation with Thrust-Fourier-Coefficients

    NASA Astrophysics Data System (ADS)

    Lubey, D.; Ko, H.; Scheeres, D.

    The classical orbit determination (OD) method of dealing with unknown maneuvers is to restart the OD process with post-maneuver observations. However, it is also possible to continue the OD process through such unknown maneuvers by representing those unknown maneuvers with an appropriate event representation. It has been shown in previous work (Ko & Scheeres, JGCD 2014) that any maneuver performed by a satellite transitioning between two arbitrary orbital states can be represented as an equivalent maneuver connecting those two states using Thrust-Fourier-Coefficients (TFCs). Event representation using TFCs rigorously provides a unique control law that can generate the desired secular behavior for a given unknown maneuver. This paper presents applications of this representation approach to orbit prediction and maneuver detection problem across unknown maneuvers. The TFCs are appended to a sequential filter as an adjoint state to compensate unknown perturbing accelerations and the modified filter estimates the satellite state and thrust coefficients by processing OD across the time of an unknown maneuver. This modified sequential filter with TFCs is capable of fitting tracking data and maintaining an OD solution in the presence of unknown maneuvers. Also, the modified filter is found effective in detecting a sudden change in TFC values which indicates a maneuver. In order to illustrate that the event representation approach with TFCs is robust and sufficiently general to be easily adjustable, different types of measurement data are processed with the filter in a realistic LEO setting. Further, cases with mis-modeling of non-gravitational force are included in our study to verify the versatility and efficiency of our presented algorithm. Simulation results show that the modified sequential filter with TFCs can detect and estimate the orbit and thrust parameters in the presence of unknown maneuvers with or without measurement data during maneuvers. With no measurement

  12. Spacecraft attitude maneuver using two single-gimbal control moment gyros

    NASA Astrophysics Data System (ADS)

    Kasai, Shinya; Kojima, Hirohisa; Satoh, Mitsunori

    2013-03-01

    In this paper, arbitrary rest-to-rest attitude maneuver problems for a satellite using two single-gimbal control moment gyros (2SGCMGs) are considered. Although single-gimbal control moment gyros are configured in the same manner as the traditional pyramid-array CMG, only two CMGs are assumed to be available. Attitude maneuver problems are similar to problems involving two reaction wheels (RWs) from the viewpoint of the number of actuators. In other words, the problem treated herein is a kind of underactuated problem. Although 2SGCMGs can generate torques around all axes, they cannot generate torques around each axis independently. Therefore, control methods designed for a satellite using two reaction wheels cannot be applied to three-axis attitude maneuver problems for a satellite using 2SGCMGs. In this paper, for simplicity, maneuvers around the x- and z-axes are first considered, and then a maneuver around the y-axis due to the corning effect resulting from the maneuver around the x- and z-axes is considered. Since maneuvers around each axis are established by the proposed method, arbitrary attitude maneuvers can be achieved using 2SGCMGs. In addition, the maneuvering angles around the z- and x-axes, which are required in order to maneuver around the y-axis, are analytically determined, and the total time required for maneuvering around the y-axis is then analyzed numerically.

  13. Experiments of Robustified Minimum-Energy Maneuvers forFlexible Space Structures

    NASA Astrophysics Data System (ADS)

    Suda, Shin-Ichi; Fujii, Hironori A.

    Experimental study is reported on the rest-to-rest maneuver applied to a model of flexible space structures. Maneuver is sometimes required to move a flexible space structure from an initial rest state without any motion to a final rest state also without any motion. It is necessary for the flexible space structure to move in minimum time with least excitation on the bending moment of the flexible structure. The model consists of a rigid body equipped with a flexible beam and is actuated by a linear motor to follow a linear motion. Three types of minimum-energy maneuver are examined experimentally: a time-optimal minimum-energy maneuver, a robustified minimum-energy maneuver, and a combination of the time-optimal and the robustified minimum-energy maneuvers, i.e., the robustified time-optimal minimum-energy maneuver. The well-known bang-bang type time-optimal and the robust time-optimal control maneuvers are also examined experimentally in order to compare their performances. The present experimental study has verified the validity of these total five types of maneuvers and show excellent agreement with the results of the numerical analysis. The excellent performance of the robustified time-optimal minimum-energy maneuver is then concluded to have superior performance in the robustness persisting the properties of the minimum-time and less fuel consumption in the maneuver.

  14. Risk of Guillain–Barré syndrome following pandemic influenza A(H1N1) 2009 vaccination in Germany†

    PubMed Central

    Prestel, Jürgen; Volkers, Peter; Mentzer, Dirk; Lehmann, Helmar C; Hartung, Hans-Peter; Keller-Stanislawski, Brigitte

    2014-01-01

    Purpose A prospective, epidemiologic study was conducted to assess whether the 2009 pandemic influenza A(H1N1) vaccination in Germany almost exclusively using an AS03-adjuvanted vaccine (Pandemrix) impacts the risk of Guillain–Barré syndrome (GBS) and its variant Fisher syndrome (FS). Methods Potential cases of GBS/FS were reported by 351 participating hospitals throughout Germany. The self-controlled case series methodology was applied to all GBS/FS cases fulfilling the Brighton Collaboration (BC) case definition (levels 1–3 of diagnostic certainty) with symptom onset between 1 November 2009 and 30 September 2010 reported until end of December 2010. Results Out of 676 GBS/FS reports, in 30 cases, GBS/FS (BC levels 1–3) occurred within 150 days following influenza A(H1N1) vaccination. The relative incidence of GBS/FS within the primary risk period (days 5–42 post-vaccination) compared with the control period (days 43–150 post-vaccination) was 4.65 (95%CI [2.17, 9.98]). Similar results were found when stratifying for infections within 3 weeks prior to onset of GBS/FS and when excluding cases with additional seasonal influenza vaccination. The overall result of temporally adjusted analyses supported the primary finding of an increased relative incidence of GBS/FS following influenza A(H1N1) vaccination. Conclusions The results indicate an increased risk of GBS/FS in temporal association with pandemic influenza A(H1N1) vaccination in Germany. © 2014 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons, Ltd. PMID:24817531

  15. Conjunction challenges of low-thrust geosynchronous debris removal maneuvers

    NASA Astrophysics Data System (ADS)

    Anderson, Paul V.; Schaub, Hanspeter

    2016-06-01

    The conjunction challenges of low-thrust engines for continuous thrust re-orbiting of geosynchronous (GEO) objects to super-synchronous disposal orbits are investigated, with applications to end-of-life mitigation and active debris removal (ADR) technologies. In particular, the low maneuverability of low-thrust systems renders collision avoidance a challenging task. This study investigates the number of conjunction events a low-thrust system could encounter with the current GEO debris population during a typical re-orbit to 300 km above the GEO ring. Sensitivities to thrust level and initial longitude and inclination are evaluated, and the impact of delaying the start time for a re-orbiting maneuver is assessed. Results demonstrate that the mean number of conjunctions increases hyperbolically as thrust level decreases, but timing the start of the maneuver appropriately can reduce the average conjunction rate when lower thrust levels are applied.

  16. Time efficient spacecraft maneuver using constrained torque distribution

    NASA Astrophysics Data System (ADS)

    Cao, Xibin; Yue, Chengfei; Liu, Ming; Wu, Baolin

    2016-06-01

    This paper investigates the time efficient maneuver of rigid satellites with inertia uncertainty and bounded external disturbance. A redundant cluster of four reaction wheels is used to control the spacecraft. To make full use of the controllability and avoid frequent unload for reaction wheels, a maximum output torque and maximum angular momentum constrained torque distribution method is developed. Based on this distribution approach, the maximum allowable acceleration and velocity of the satellite are optimized during the maneuvering. A novel braking curve is designed on the basis of the optimization strategy of the control torque distribution. A quaternion-based sliding mode control law is proposed to render the state to track the braking curve strictly. The designed controller provides smooth control torque, time efficiency and high control precision. Finally, practical numerical examples are illustrated to show the effectiveness of the developed torque distribution strategy and control methodology.

  17. Optimal Variable-Structure Control Tracking of Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Crassidis, John L.; Vadali, Srinivas R.; Markley, F. Landis

    1999-01-01

    An optimal control approach using variable-structure (sliding-mode) tracking for large angle spacecraft maneuvers is presented. The approach expands upon a previously derived regulation result using a quaternion parameterization for the kinematic equations of motion. This parameterization is used since it is free of singularities. The main contribution of this paper is the utilization of a simple term in the control law that produces a maneuver to the reference attitude trajectory in the shortest distance. Also, a multiplicative error quaternion between the desired and actual attitude is used to derive the control law. Sliding-mode switching surfaces are derived using an optimal-control analysis. Control laws are given using either external torque commands or reaction wheel commands. Global asymptotic stability is shown for both cases using a Lyapunov analysis. Simulation results are shown which use the new control strategy to stabilize the motion of the Microwave Anisotropy Probe spacecraft.

  18. A lightweight pumped hydrazine orbit maneuvering space vehicle

    NASA Astrophysics Data System (ADS)

    Whitehead, J. C.

    1992-01-01

    An orbital maneuvering vehicle has a pair of opposed cylindrical piston tanks for hydrazine, and four transverse liquid rocket engines along a longitudinal plane. A new kind of pumped rocket propulsion provides maneuvering thrust on demand, and free-piston pumps which can rapidly start and stop are radially oriented between thrusters. A major advantage of this configuration is that the tanks can be close together, which maximizes the vehicle's longitudinal bending stiffness while minimizing the mass of the central bridging structure. The impulses from pump exhaust and piston reciprocation are directed through the system mass center, so they apply no disturbance torques. All high-temperature components are located on the outside of the central structure, where they are free to expand and radiate heat without detrimental effects. Virtually all lightweight components have been fabricated and tested, and photographs of hardware subassemblies are presented.

  19. Control of large angle maneuvers for the flexible solar sail

    NASA Astrophysics Data System (ADS)

    Zhang, Jin; Zhai, Kun; Wang, TianShu

    2011-04-01

    Solar sail is a new type of spacecraft for deep space exploration, which flies by the pressure of sunlight. The attitude of the sail determines its orbit, so altitude control plays an important role in the mission. However, the large flexible structure leads to some difficulty in attitude control. This paper establishes the reduced dynamic model of a flexible solar sail with foreshortening deformation, and coupling with its attitude and vibration. As usual, large angle maneuvering will lead to the vibration of flexible structure, so the time optimal control of solar sail maneuvering is considered. Bang-Bang control of the solar sail generates large amplitude and sustained vibration, while the combined control based on input shaping can eliminate the vibration efficiently. With the comparison of two reduced models, it is demonstrated that the choice of two models depends on the attention to the stretching deformation.

  20. Visual display aid for orbital maneuvering - Design considerations

    NASA Technical Reports Server (NTRS)

    Grunwald, Arthur J.; Ellis, Stephen R.

    1993-01-01

    This paper describes the development of an interactive proximity operations planning system that allows on-site planning of fuel-efficient multiburn maneuvers in a potential multispacecraft environment. Although this display system most directly assists planning by providing visual feedback to aid visualization of the trajectories and constraints, its most significant features include: (1) the use of an 'inverse dynamics' algorithm that removes control nonlinearities facing the operator, and (2) a trajectory planning technique that separates, through a 'geometric spreadsheet', the normally coupled complex problems of planning orbital maneuvers and allows solution by an iterative sequence of simple independent actions. The visual feedback of trajectory shapes and operational constraints, provided by user-transparent and continuously active background computations, allows the operator to make fast, iterative design changes that rapidly converge to fuel-efficient solutions. The planning tool provides an example of operator-assisted optimization of nonlinear cost functions.

  1. Heterogeneous Multiple Sensors Joint Tracking of Maneuvering Target in Clutter

    PubMed Central

    Wu, Panlong; Li, Xingxiu; Kong, Jianshou; Liu, Jiale

    2015-01-01

    To solve the problem of tracking maneuvering airborne targets in the presence of clutter, an improved interacting multiple model probability data association algorithm (IMMPDA-MDCM) using radar/IR sensors fusion is proposed. Under the architecture of the proposed algorithm, the radar/IR centralized fusion tracking scheme of IMMPDA-MDCM is designed to guarantee the observability of the target state. The interacting multiple model (IMM) deals with the model switching. The modified debiased converted measurement (MDCM) filter accounts for non-linearity in the dynamic system models, and reduces the effect of measurement noise on the covariance effectively. The probability data association (PDA) handles data association and measurement uncertainties in clutter. The simulation results show that the proposed algorithm can improve the tracking precision for maneuvering target in clutters, and has higher tracking precision than the traditional IMMPDA based on EKF and IMMPDA based on DCM algorithm. PMID:26193279

  2. Does dragonfly's abdomen flexion help with fast turning maneuvers?

    NASA Astrophysics Data System (ADS)

    Liu, Geng; Li, Chengyu; Dong, Haibo; Flow Simulation Research Group Team

    2013-11-01

    Dragonflies are able to achieve fast turning maneuvers during take-off flights. Both asymmetric wing flapping and abdomen flexion have been observed during the fast turning. It's widely thought that the asymmetric wing beats are responsible of producing the aerodynamic moment needed for the body rotation. However, the dynamic effect of the abdomen flexion is not clear yet. In this study, an integrated experimental and computational approach is used to study the underlying dynamic effect of dragonfly abdomen flexion. It's found that dragonfly abdomen tended to bend towards the same side as the body reorienting to. Quantitative analysis have shown that during take-off turning maneuver the abdomen flexion can modulate the arm of force by changing the position of the center of mass relative to the thorax. As a result, roll and yaw moments produced by the wing flapping can be enhanced. This work is supported by NSF CBET-1313217. This work is supported by NSF CBET-1313217.

  3. Design and analysis of a supersonic penetration/maneuvering fighter

    NASA Technical Reports Server (NTRS)

    Child, R. D.

    1975-01-01

    The design of three candidate air combat fighters which would cruise effectively at freestream Mach numbers of 1.6, 2.0, and 2.5 while maintaining good transonic maneuvering capability, is considered. These fighters were designed to deliver aerodynamically controlled dogfight missiles at the design Mach numbers. Studies performed by Rockwell International in May 1974 and guidance from NASA determined the shape and size of these missiles. The principle objective of this study is the aerodynamic design of the vehicles; however, configurations are sized to have realistic structures, mass properties, and propulsion systems. The results of this study show that air combat fighters in the 15,000 to 23,000 pound class would cruise supersonically on dry power and still maintain good transonic maneuvering performance.

  4. Thermally-Constrained Fuel-Optimal ISS Maneuvers

    NASA Technical Reports Server (NTRS)

    Bhatt, Sagar; Svecz, Andrew; Alaniz, Abran; Jang, Jiann-Woei; Nguyen, Louis; Spanos, Pol

    2015-01-01

    Optimal Propellant Maneuvers (OPMs) are now being used to rotate the International Space Station (ISS) and have saved hundreds of kilograms of propellant over the last two years. The savings are achieved by commanding the ISS to follow a pre-planned attitude trajectory optimized to take advantage of environmental torques. The trajectory is obtained by solving an optimal control problem. Prior to use on orbit, OPM trajectories are screened to ensure a static sun vector (SSV) does not occur during the maneuver. The SSV is an indicator that the ISS hardware temperatures may exceed thermal limits, causing damage to the components. In this paper, thermally-constrained fuel-optimal trajectories are presented that avoid an SSV and can be used throughout the year while still reducing propellant consumption significantly.

  5. Evasive Maneuvers in Route Collision With Space Debris Cloud

    NASA Astrophysics Data System (ADS)

    Jesus, A. D. C.; Sousa, R. R.; Neto, E. V.

    2015-10-01

    Collisions between operational vehicles and space debris can completely derail the continuity of space missions, especially if there is chain collisions between debris, which generate even smaller fragments. In this paper, we investigate the dynamics on between an operational vehicle and space debris that form a cloud, considering the possibility of collisions between debris during an evasive maneuver the vehicle. For a radius of 3 km celestial sphere, we find possibilities of collision between debris up to 10 m, while the vehicle performs an evasive maneuver in time 3,000 s range. These results depend on the time collision, the angular positions of the collisional objects and the amount of debris that form the cloud.

  6. Time-optimal maneuvering control of a rigid spacecraft

    NASA Astrophysics Data System (ADS)

    Lai, Li-Chun; Yang, Chi-Ching; Wu, Chia-Ju

    2007-05-01

    The time-optimal rest-to-rest maneuvering control problem of a rigid spacecraft is studied in this paper. By utilizing an iterative procedure, this problem is formulated and solved as a constrained nonlinear programming (NLP) one. In this novel method, the count of control steps is fixed initially and the sampling period is treated as a variable in the optimization process. The optimization object is to minimize the sampling period below a specific minimum value, which is set in advance considering the accuracy of discretization. To generate initial feasible solutions of the NLP problem, a genetic-algorithm-based is also proposed such that the optimization process can be started from many different points to find the globally optimal solution. With the proposed method, one can find a time-optimal rest-to-rest maneuver of the rigid spacecraft between two attitudes. To show the feasibility of the proposed method, simulation results are included for illustration.

  7. Neural optimal control of flexible spacecraft slew maneuver

    NASA Astrophysics Data System (ADS)

    Nayeri, M. Reza Dehghan; Alasty, Aria; Daneshjou, Kamran

    2004-11-01

    This paper deals with the problem of optimal large-angle single-axis maneuvers of a flexible spacecraft with simultaneous vibration suppression of elastic modes. A spacecraft model with a cylindrical hub and one flexible appendage and tip mass is considered. Gravity gradient torque is considered as a disturbance torque. Multilayer perceptron neural networks are used to design a Neural Optimal Controller (NOC) for this multivariable non-linear maneuver. For NOC training, an off-line training procedure based on backpropagation through time algorithm is developed to minimize the general quadratic cost function in forward and backward pass stages. The proposed controller is also applicable to simultaneous multi-axis reorientation of a flexible spacecraft. Simulation results are presented to show that very fast reference pitch angle trajectory tracking and vibration suppression are accomplished.

  8. Orbital flight test of the manned maneuvering unit

    NASA Technical Reports Server (NTRS)

    Stewart, R. L.

    1984-01-01

    Based on the experience provided by the first astronaut maneuvering unit used in the early extravehicular activities missions, a manned maneuvering unit (MMU) was developed that culminated in emergence of the M509 unit. The M509 unit, flown on the STS41-B, is a self-contained propulsive backpack. A flight support station (FSS) provides cargo bay stowage for the MMU, serves as a donning/doffing station, and provides an interface with the Orbiter gaseous nitrogen system for propellant refueling, electrical power for heaters, and temperature instrumentation. The MMU propulsion system, its control system, the electrical system and the flight displays are described. The orbital flight test has demonstrated superior handling and flying qualities of the MMU.

  9. Broken-Plane Maneuver Applications for Earth to Mars Trajectories

    NASA Technical Reports Server (NTRS)

    Abilleira, Fernando

    2007-01-01

    Optimization techniques are critical when investigating Earth to Mars trajectories since they have the potential of reducing the total (delta)V of a mission. A deep space maneuver (DSM) executed during the cruise may improve a trajectory by reducing the total mission V. Nonetheless, DSMs not only may improve trajectory performance (from an energetic point of view) but also open up new families of trajectories that would satisfy very specific mission requirements not achievable with ballistic trajectories. In the following pages, various specific examples showing the potential advantages of the usage of broken plane maneuvers will be introduced. These examples correspond to possible scenarios for Earth to Mars trajectories during the next decade (2010-2020).

  10. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... factor n for any speed up to Vn may not be less than 2.1+24,000/ (W +10,000) except that n may not be less than 2.5 and need not be greater than 3.8—where W is the design maximum takeoff weight. (c) The... vary linearly with speed from the value at V C to zero at V D. (d) Maneuvering load factors lower...

  11. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... factor n for any speed up to Vn may not be less than 2.1+24,000/ (W +10,000) except that n may not be less than 2.5 and need not be greater than 3.8—where W is the design maximum takeoff weight. (c) The... vary linearly with speed from the value at V C to zero at V D. (d) Maneuvering load factors lower...

  12. 14 CFR 25.337 - Limit maneuvering load factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... factor n for any speed up to Vn may not be less than 2.1+24,000/ (W +10,000) except that n may not be less than 2.5 and need not be greater than 3.8—where W is the design maximum takeoff weight. (c) The... vary linearly with speed from the value at V C to zero at V D. (d) Maneuvering load factors lower...

  13. Efficient Reorientation Maneuvers for Spacecraft with Multiple Articulated Payloads

    NASA Technical Reports Server (NTRS)

    Mcclamroch, N. Harris

    1993-01-01

    A final report is provided which describes the research program during the period 3 Mar. 1992 to 3 Jun. 1993. A summary of the technical research questions that were studied and of the main results that were obtained is given. The specific outcomes of the research program, including both educational impacts as well as research publications, are listed. The research is concerned with efficient reorientation maneuvers for spacecraft with multiple articulated payloads.

  14. Stability and control of maneuvering high-performance aircraft

    NASA Technical Reports Server (NTRS)

    Stengel, R. F.; Berry, P. W.

    1977-01-01

    The stability and control of a high-performance aircraft was analyzed, and a design methodology for a departure prevention stability augmentation system (DPSAS) was developed. A general linear aircraft model was derived which includes maneuvering flight effects and trim calculation procedures for investigating highly dynamic trajectories. The stability and control analysis systematically explored the effects of flight condition and angular motion, as well as the stability of typical air combat trajectories. The effects of configuration variation also were examined.

  15. Functional Connectivity during Modulation of Tinnitus with Orofacial Maneuvers

    PubMed Central

    Lee, Megan H.; Solowski, Nancy; Wineland, Andre; Okuyemi, Oluwafunmilola; Nicklaus, Joyce; Kallogjeri, Dorina; Piccirillo, Jay F.; Burton, Harold

    2014-01-01

    Objective To determine changes in cortical neural networks as defined by resting-state functional connectivity magnetic resonance imaging during voluntary modulation of tinnitus with orofacial maneuvers. Study Design Cross-sectional study. Setting Academic medical center. Subjects and Methods Participants were scanned during the maneuver and also at baseline to serve as their own control. The authors chose, a priori, 58 seed regions to evaluate previously described cortical neural networks by computing temporal correlations between all seed region pairs. Seed regions whose correlations significantly differed between rest and maneuver (P < .05, uncorrected) entered into a second-stage analysis of computing the correlation coefficient between the seed region and time courses in each of the remaining brain voxels. A threshold-free cluster enhancement permutation analysis evaluated the distribution of these correlation coefficients after transformation to Fisher z scores and registration to a surface-based reconstruction using Freesurfer. Results The median age for the 16 subjects was 54 years (range, 27–72 years), and all had subjective, unilateral or bilateral, nonpulsatile tinnitus for 6 months or longer. In 9 subjects who could voluntarily increase the loudness of their tinnitus, there were no significant differences in functional connectivity in any cortical networks. A separate analysis evaluated results from 3 patients who decreased the loudness of their tinnitus. Four subjects were excluded because of excessive motion in the scanner. Conclusion The absence of significant differences in functional connectivity due to voluntary orofacial maneuvers that increased tinnitus loudness failed to confirm prior reports of altered cerebral blood flows during somatomotor behaviors. PMID:22675003

  16. Space shuttle orbit maneuvering engine reusable thrust chamber program

    NASA Technical Reports Server (NTRS)

    Pauckert, R. P.; Yost, M. C.; Tobin, R. D.

    1973-01-01

    Tests were conducted on the regenerative cooled thrust chamber of the space shuttle orbit maneuvering engine. The conditions for the tests and the durations obtained are presented. The tests demonstrated thrust chamber operation over the nominal ranges of chamber pressure mixture ratio. Variations in auxiliary film coolant flowrate were also demonstrated. High pressure tests were conducted to demonstrate the thrust chamber operation at conditions approaching the design chamber pressure for the derivative space tug application.

  17. Flow Modulation and Force Control in Insect Fast Maneuver

    NASA Astrophysics Data System (ADS)

    Li, Chengyu; Dong, Haibo; Zhang, Wen; Gai, Kuo

    2012-11-01

    In this work, an integrated study combining high-speed photogrammetry and direct numerical simulation (DNS) is used to study free flying insects in fast maneuver. Quantitative measurement has shown the significant differences between quad-winged flyers such as dragonfly and damselfly and two-winged flyers such as cicada. Comparisons of unsteady 3D vortex formation and associated aerodynamic force production reveal the different mechanisms used by insects in fast turn. This work is supported by NSF CBET-1055949.

  18. Differential Evolution Optimization for Targeting Spacecraft Maneuver Plans

    NASA Technical Reports Server (NTRS)

    Mattern, Daniel

    2016-01-01

    Previous analysis identified specific orbital parameters as being safer for conjunction avoidance for the TDRS fleet. With TDRS-9 being considered an at-risk spacecraft, a potential conjunction concern was raised should TDRS-9 fail while at a longitude of 12W. This document summarizes the analysis performed to identify if these specific orbital parameters could be targeted using the remaining drift-termination maneuvers for the relocation of TDRS-9 from 41W longitude to 12W longitude.

  19. Control integration concept for hypersonic cruise-turn maneuvers

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Lallman, Frederick J.

    1992-01-01

    Piloting difficulties associated with conducting aircraft maneuvers in hypersonic flight are caused in part by the nonintuitive nature of the aircraft response and the stringent constraints anticipated on allowable angle of attack and dynamic pressure variations. An approach is documented that provides precise, coordinated maneuver control during excursions from a hypersonic cruise flight path and the necessary flight condition constraints. The approach is to achieve specified guidance commands by resolving altitude and cross range errors into a load factor and bank angle command by using a coordinate transformation that acts as an interface between outer and inner loop flight controls. This interface, referred to as a 'resolver', applies constraints on angle of attack and dynamic pressure perturbations while prioritizing altitude regulation over cross range. An unpiloted test simulation, in which the resolver was used to drive inner loop flight controls, produced time histories of responses to guidance commands and atmospheric disturbances at Mach numbers of 6, 10, 15, and 20. Angle of attack and throttle perturbation constraints, combined with high speed flight effects and the desire to maintain constant dynamic pressure, significantly impact the maneuver envelope for a hypersonic vehicle.

  20. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    NASA Technical Reports Server (NTRS)

    Scarritt, Sara K.; Marchand, Belinda G.; Weeks, Michael W.

    2009-01-01

    In earlier investigations, the adaptation and implementation of a modified two-level corrections process as the onboard targeting algorithm for the Trans-Earth Injection phase of Orion is presented. The objective of that targeting algorithm is to generate the times of ignition and magnitudes of the required maneuvers such that the desired state at entry interface is achieved. In an actual onboard flight software implementation, these times of ignition and maneuvers are relayed onto Flight Control for command and execution. Although this process works well when the burn durations or burn arcs are small, this might not be the case during a contingency situation when lower thrust engines are employed to perform the maneuvers. Therefore, a new version of the modified two-level corrections process is formulated to handle the case of finite burn arcs. This paper presents the development and formulation of that finite burn modified two-level corrections process which can again be used as an onboard targeting algorithm for the Trans-Earth Injection phase of Orion. Additionally, performance results and a comparison between the two methods are presented. The finite burn two-level corrector formulation presented here ensures the entry constraints at entry interface are still met without violating the available fuel budget, while still accounting for much longer burn times in its design.

  1. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    NASA Technical Reports Server (NTRS)

    Scarritt, Sara K.; Marchand, Belinda G.; Brown, Aaron J.; Tracy, William H.; Weeks, Michael W.

    2010-01-01

    In earlier investigations, the adaptation and implementation of a modified two-level corrections (or targeting) process as the onboard targeting algorithm for the Trans-Earth Injection phase of Orion is presented. The objective of that targeting algorithm is to generate the times of ignition and magnitudes of the required maneuvers such that the desired state at entry interface is achieved. In an actual onboard flight software implementation, these times of ignition and maneuvers are relayed onto Flight Control for command and execution. Although this process works well when the burn durations or burn arcs are small, this might not be the case during a contingency situation when lower thrust engines are employed to perform the maneuvers. Therefore, a new model for the two-level corrections process is formulated here to accommodate finite burn arcs. This paper presents the development and formulation of the finite burn two-level corrector, used as an onboard targeting algorithm for the Trans-Earth Injection phase of Orion. A performance comparison between the impulsive and finite burn models is also presented. The present formulation ensures all entry constraints are met, without violating the available fuel budget, while allowing for low-thrust scenarios with long burn durations.

  2. Optimal scheduling of multispacecraft refueling based on cooperative maneuver

    NASA Astrophysics Data System (ADS)

    Du, Bingxiao; Zhao, Yong; Dutta, Atri; Yu, Jing; Chen, Xiaoqian

    2015-06-01

    The scheduling of multispacecraft refueling based on cooperative maneuver in a circular orbit is studied in this paper. In the proposed scheme, both of the single service vehicle (SSV) and the target satellite (TS) perform the orbital transfer to complete the rendezvous at the service places. When a TS is refueled by the SSV, it returns to its original working slot to continue its normal function. In this way, the SSV refuels the TS one by one. A MINLP model for the mission is first built, then a two-level hybrid optimization approach is proposed for determining the strategy, and the optimal solution is successfully obtained by using an algorithm which is a combination of Multi-island Genetic Algorithm and Sequential Quadratic Programming. Results show the cooperative strategy can save around 27.31% in fuel, compared with the non-cooperative strategy in which only the SSV would maneuver in the example considered. Three conclusions can be drawn based on the numerical simulations for the evenly distributed constellations. Firstly, in the cooperative strategy one of the service positions is the initial location of the SSV, other service positions are also target slots, i.e. not all targets need to maneuver, and there may be more than one TS serviced in a given service position. Secondly, the efficiency gains for the cooperative strategy are higher for larger transferred fuel mass. Thirdly, the cooperative strategy is less efficient for targets with larger spacecraft mass.

  3. A Fuel-Efficient Conflict Resolution Maneuver for Separation Assurance

    NASA Technical Reports Server (NTRS)

    Bowe, Aisha Ruth; Santiago, Confesor

    2012-01-01

    Automated separation assurance algorithms are envisioned to play an integral role in accommodating the forecasted increase in demand of the National Airspace System. Developing a robust, reliable, air traffic management system involves safely increasing efficiency and throughput while considering the potential impact on users. This experiment seeks to evaluate the benefit of augmenting a conflict detection and resolution algorithm to consider a fuel efficient, Zero-Delay Direct-To maneuver, when resolving a given conflict based on either minimum fuel burn or minimum delay. A total of twelve conditions were tested in a fast-time simulation conducted in three airspace regions with mixed aircraft types and light weather. Results show that inclusion of this maneuver has no appreciable effect on the ability of the algorithm to safely detect and resolve conflicts. The results further suggest that enabling the Zero-Delay Direct-To maneuver significantly increases the cumulative fuel burn savings when choosing resolution based on minimum fuel burn while marginally increasing the average delay per resolution.

  4. Severe Turbulence and Maneuvering from Airline Flight Records

    NASA Technical Reports Server (NTRS)

    Wingrove, Rodney C.; Bach, R. E., Jr.

    1994-01-01

    Digital flight records from reported clear-air turbulence incidents are used to determine winds and turbulence, to determine maneuver g loads, and to analyze control problems. Many cases of severe turbulence are found downwind of mountains and thunderstorms where sharp, sudden jolts are associated with vortices in atmospheric waves. Other cases of severe turbulence are round in strong updrafts above thunderstorm buildups that may be undetected by onboard weather radar. An important finding is that there are large maneuvering loads in over half of the reported clear-air turbulence incidents. Maneuvering loads are determined through an analysis of the short-term variations in elevator deflection and aircraft pitch angle. For altitude control in mountain waves the results indicate that small pitch angle changes with proper timing are sufficient to counter variations in vertical wind. For airspeed control in strong mountain waves, however, there is neither the available thrust nor the quickness in engine response necessary to counter the large variations in winds.

  5. PM Science Working Group Meeting on Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Parkinson, Claire L.

    1997-01-01

    The EOS PM Science Working Group met on May 6, 1997, to examine the issue of spacecraft maneuvers. The meeting was held at NASA Goddard Space Flight Center and was attended by the Team Leaders of all four instrument science teams with instruments on the PM-1 spacecraft, additional representatives from each of the four teams, the PM Project management, and random others. The meeting was chaired by the PM Project Scientist and open to all. The meeting was called in order to untangle some of the concerns raised over the past several months regarding whether or not the PM-1 spacecraft should undergo spacecraft maneuvers to allow the instruments to obtain deep-space views. Two of the Science Teams, those for the Moderate-Resolution Imaging Spectroradiometer (MODIS) and the Clouds and the Earth's Radiant Energy System (CERES), had strongly expressed the need for deep-space views in order to calibrate their instruments properly and conveniently. The other two teams, those for the Advanced Microwave Scanning Radiometer (AMSR-E) and the Atmospheric Infrared Sounder (AIRS), the Advanced Microwave Sounding Unit (AMSU), and the Humidity Sounder for Brazil (HSB), had expressed concerns that the maneuvers involve risks to the instruments and undesired gaps in the data sets.

  6. Capturing and analyzing wheelchair maneuvering patterns with mobile cloud computing.

    PubMed

    Fu, Jicheng; Hao, Wei; White, Travis; Yan, Yuqing; Jones, Maria; Jan, Yih-Kuen

    2013-01-01

    Power wheelchairs have been widely used to provide independent mobility to people with disabilities. Despite great advancements in power wheelchair technology, research shows that wheelchair related accidents occur frequently. To ensure safe maneuverability, capturing wheelchair maneuvering patterns is fundamental to enable other research, such as safe robotic assistance for wheelchair users. In this study, we propose to record, store, and analyze wheelchair maneuvering data by means of mobile cloud computing. Specifically, the accelerometer and gyroscope sensors in smart phones are used to record wheelchair maneuvering data in real-time. Then, the recorded data are periodically transmitted to the cloud for storage and analysis. The analyzed results are then made available to various types of users, such as mobile phone users, traditional desktop users, etc. The combination of mobile computing and cloud computing leverages the advantages of both techniques and extends the smart phone's capabilities of computing and data storage via the Internet. We performed a case study to implement the mobile cloud computing framework using Android smart phones and Google App Engine, a popular cloud computing platform. Experimental results demonstrated the feasibility of the proposed mobile cloud computing framework. PMID:24110214

  7. Aerodynamic role of dynamic wing morphing in hummingbird maneuvering flight

    NASA Astrophysics Data System (ADS)

    Ren, Yan; Shallcross, Gregory; Dong, Haibo; Deng, Xinyan; Tobalske, Bret; Flow Simulation Research Group Team; Bio-robotics lab Collaboration; University of Montana Flight Laboratory Collaboration

    2014-11-01

    The flexibility and deformation of hummingbird wing gives hummingbird a great degree of control over fluid forces in flapping flight. Unlike insect wing's passive deformation, hummingbird wing employs a more complicated wing morphing mechanism through both active muscle control and passive feather-air interaction, which results in highly complex 3D wing topology variations during the unsteady flight. Three camera high speed (1000 fps) high resolution digital video was taken and digitized to measure 3D wing conformation in all its complexity during steady flying and maneuvering. Results have shown that the dynamic wing morphing is more prominent in maneuvering flight. Complicated cambering and twisting patterns are observed along the wing pitching axis. A newly developed immersed boundary method which realistically models wing-joint-body of the hummingbird is then employed to simulate the flow associated with dynamic morphing. The simulations provide a first of its kind glimpse of the fluid and vortex dynamics associated with dynamic wing morphing and aerodynamic force computations allow us to gain a better understanding of force producing mechanisms in hummingbird maneuvering flight. This work is supported by AFOSR FA9550-12-1-007 and NSF CEBT-1313217.

  8. Trajectory Control of Rendezvous with Maneuver Target Spacecraft

    NASA Technical Reports Server (NTRS)

    Zhou, Zhinqiang

    2012-01-01

    In this paper, a nonlinear trajectory control algorithm of rendezvous with maneuvering target spacecraft is presented. The disturbance forces on the chaser and target spacecraft and the thrust forces on the chaser spacecraft are considered in the analysis. The control algorithm developed in this paper uses the relative distance and relative velocity between the target and chaser spacecraft as the inputs. A general formula of reference relative trajectory of the chaser spacecraft to the target spacecraft is developed and applied to four different proximity maneuvers, which are in-track circling, cross-track circling, in-track spiral rendezvous and cross-track spiral rendezvous. The closed-loop differential equations of the proximity relative motion with the control algorithm are derived. It is proven in the paper that the tracking errors between the commanded relative trajectory and the actual relative trajectory are bounded within a constant region determined by the control gains. The prediction of the tracking errors is obtained. Design examples are provided to show the implementation of the control algorithm. The simulation results show that the actual relative trajectory tracks the commanded relative trajectory tightly. The predicted tracking errors match those calculated in the simulation results. The control algorithm developed in this paper can also be applied to interception of maneuver target spacecraft and relative trajectory control of spacecraft formation flying.

  9. Global Precipitation Measurement (GPM) Orbit Design and Autonomous Maneuvers

    NASA Technical Reports Server (NTRS)

    Folta, David; Mendelsohn, Chad; Mailhe, Laurie

    2003-01-01

    The NASA Goddard Space Flight Center's Global Precipitation Measurement (GPM) mission must meet the challenge of measuring worldwide precipitation every three hours. The GPM core spacecraft, part of a constellation, will be required to maintain a circular orbit in a high drag environment at a near-critical inclination. Analysis shows that a mean orbit altitude of 407 km is necessary to prevent ground track repeating. Combined with goals to minimize maneuver operation impacts to science data collection and to enable reasonable long-term orbit predictions, the GPM project has decided to fly the GSFC autonomous maneuver system, AutoCon(TM). This system is a follow-up version of the highly successful New Millennium Program technology flown onboard the Earth Observing-1 formation flying mission. This paper presents the driving science requirements and goals of the GPM mission and shows how they will be met. Selection of the mean semi-major axis, eccentricity, and the AV budget for several ballistic properties are presented. The architecture of the autonomous maneuvering system to meet the goals and requirements is presented along with simulations using GPM parameters. Additionally, the use of the GPM autonomous system to mitigate possible collision avoidance and to aid other spacecraft systems during navigation outages is explored.

  10. Alveolar recruitment maneuvers: are your patients missing out?

    PubMed

    Hartland, Benjamin L; Newell, Timothy J; Damico, Nicole

    2014-08-01

    Awake, spontaneously breathing humans sigh on average 9 to 10 times per hour. The sigh is a normal homeostatic reflex proposed to maintain pulmonary compliance and decrease the formation of atelectasis by recruiting collapsed alveoli. The induction and maintenance of anesthesia with muscle paralysis and a fixed tidal volume abolish the sigh. Without periodic sighs, patients are left susceptible to atelectasis and its negative sequelae. The prevalence of atelectasis has been estimated to be as high as 100% in patients undergoing general anesthesia. A strong correlation between atelectasis and postoperative pulmonary complications has been demonstrated. Postoperative pulmonary complications lengthen hospital stays and increase healthcare costs. Alveolar recruitment maneuvers, which make up one component of open lung ventilation, have been described as vital capacity breaths, double tidal volume breaths, and sigh breaths. These simple maneuvers result in a sustained increase in airway pressure that serves to recruit collapsed alveoli and improve arterial oxygenation. This article examines the literature regarding the application of alveolar recruitment maneuvers in the perioperative setting. The format is a series of clinically oriented questions posed to help the reader translate available evidence into practice. PMID:25167611

  11. Maneuver Performance Enhancement for an Advanced Fighter/Attack Aircraft

    NASA Technical Reports Server (NTRS)

    Samuels, Jeff; Langan, Kevin J.; Schmitz, Frederic H. (Technical Monitor)

    1994-01-01

    A small scale wind tunnel test of a realistic fighter configuration has been completed in NASA Ames' 7'x10' wind tunnel. This test was part of the Fighter Lift and Control (FLAC) program, a joint NASA - USAF research program, involving small and large-scale wind-tunnel tests and computational analysis of unique lift augmentation and control devices. The goal of this program is to enhance the maneuver and control capability of next-generation Air Force multi-role fighter aircraft with low-observables geometries. The principal objective of this test was to determine the effectiveness of passive boundary layer control devices at increasing L/D at sustained maneuver lift coefficients. Vortex generators (VGs) were used to energize the boundary layer to prevent or delay separation. Corotating vanes, counter-rotating vanes, and Wheeler Wishbone VGs were used in the vicinity of the leading and trailing edge flap hinge lines. Principle test parameters were leading and trailing edge flap deflections, and location, size, spacing, and orientation for each VG type. Gurney flaps were also tested. Data gathered include balance force and moment data, surface pressures, and flow visualization for characterizing flow behavior and locating separation lines. Results were quite different for the two best flap configurations tested. All VG types tested showed improvement (up to 5%) in maneuver L/D with flaps at LE=20 degrees, TE=0 degrees. The same VGs degraded performance, in all but a few cases, with flaps at LE=15 degrees, TE=10 degrees.

  12. Changes in the period of the eclipsing system AH Virginis

    NASA Astrophysics Data System (ADS)

    Kennedy, H. D.

    Guthnick and Prager (1929) discovered the variability of AH Virginis. On the basis of later observations, AH Virginis was classified as one of the few W UMa systems which display complete eclipses at an inclination likely to be closer to 90 deg than to 61 deg. Observations made in connection with the present study confirm constancy of light of 40 minutes duration during primary minimum. The present observations indicate curved as well as flat secondary minima. The variable was observed photoelectrically in yellow light with the 38-cm reflector during one night in April and five nights in May, 1981. A total of 73 observations defining primary minimum (ingress and egress), and 66 observations defining secondary minimum was obtained.

  13. Precursor systems analyses of automated highway systems. Activity area I. Impact of AHS on surrounding non-AHS roadways. Final report, September 1993-November 1994

    SciTech Connect

    Lima, P.; Wert, A.; Crowe, E.; O`Brien, S.; Roper, D.

    1995-05-01

    The study considers the influence which automated highway system (AHS) traffic would have on the conventional, non-automated freeway and street system as it approaches and departs from the automated roadway. The higher speeds and capacities possible with an AHS facility will attract traffic into the AHS lane from both the general purpose freeway lanes and the parallel arterials. The increased AHS traffic will have both positive and negative impacts on the surrounding street system. The analysis includes the modeling and evaluation of the operations of a freeway corridor with and without an AHS lane. Operations with and without an AHS lane on the surrounding roadways are then evaluated using traffic operations measures of effectiveness. The surrounding roadways include the general purpose freeway lanes, freeway ramps, parallel arterials, and cross streets. Additional modeling analyzes the impact of the AHS traffic on the cross streets. The Highway Capacity Software (HCS) program is used to evaluate the level-of-service on alternative configurations of the cross streets and parallel arterials. The physical requirements of the AHS lane and ramps are analyzed to determine the impact on the surrounding streets. The modeling results are also used as input to the Activity P analysis. Qualitative as well as quantitative impacts are addressed. AHS is reviewed from the perspective of an urban planner.

  14. Hot gas ingestion effects on fuel control surge recovery and AH-1 rotor drive train torque spikes

    NASA Technical Reports Server (NTRS)

    Tokarski, Frank; Desai, Mihir; Books, Martin; Zagranski, Raymond

    1994-01-01

    This report summarizes the work accomplished through computer simulation to understand the impact of the hydromechanical turbine assembly (TA) fuel control on rocket gas ingestion induced engine surges on the AH-1 (Cobra) helicopter. These surges excite the lightly damped torsional modes of the Cobra rotor drive train and can cause overtorqueing of the tail rotor shaft. The simulation studies show that the hydromechanical TA control has a negligible effect on drive train resonances because its response is sufficiently attenuated at the resonant frequencies. However, a digital electronic control working through the TA control's separate, emergency fuel metering system has been identified as a solution to the overtorqueing problem. State-of-the-art software within the electronic control can provide active damping of the rotor drive train to eliminate excessive torque spikes due to any disturbances including engine surges and aggressive helicopter maneuvers. Modifications to the existing TA hydromechanical control are relatively minor, and existing engine sensors can be utilized by the electronic control. Therefore, it is concluded that the combination of full authority digital electronic control (FADEC) with hydromechanical backup using the existing TA control enhances flight safety, improves helicopter performance, reduces pilot workload, and provides a substantial payback for very little investment.

  15. X-31 Demonstrating High Angle of Attack - Herbst Maneuver

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The X-31 aircraft on a research mission from NASA's Dryden Flight Research Facility, Edwards, California, is flying nearly perpendicular to the flight path while performing the Herbst maneuver. Effectively using the entire airframe as a speed brake and using the aircraft's unique thrust vectoring system to maintain control, the pilot rapidly rolls the aircraft to reverse the direction of flight, completing the maneuver with acceleration back to high speed in the opposite direction. This type of turning capability could reduce the turning time of a fighter aircraft by 30 percent. The Herbst maneuver was first conducted in an X-31 on April 29, 1993, in the No. 2 aircraft by German test pilot Karl-Heinz Lang. The X-31 Enhanced Fighter Maneuverability (EFM) demonstrator flew at the Ames- Dryden Flight Research Facility, Edwards, California (redesignated the Dryden Flight Research Center in 1994) from February 1992 until 1995 and before that at the Air Force's Plant 42 in Palmdale, California. The goal of the project was to provide design information for the next generation of highly maneuverable fighter aircraft. This program demonstrated the value of using thrust vectoring (directing engine exhaust flow) coupled with an advanced flight control system to provide controlled flight to very high angles of attack. The result was a significant advantage over most conventional fighters in close-in combat situations. The X-31 flight program focused on agile flight within the post-stall regime, producing technical data to give aircraft designers a better understanding of aerodynamics, effectiveness of flight controls and thrust vectoring, and airflow phenomena at high angles of attack. Stall is a condition of an airplane or an airfoil in which lift decreases and drag increases due to the separation of airflow. Thrust vectoring compensates for the loss of control through normal aerodynamic surfaces that occurs during a stall. Post-stall refers to flying beyond the normal stall

  16. Application of a Comprehensive Analytical Model of Rotor Aerodynamics and Dynamics (CAMRAD) to the McDonnell Douglas AH-64A helicopter

    NASA Technical Reports Server (NTRS)

    Callahan, Cynthia B.; Bassett, Duane E.

    1988-01-01

    A model of the AH-64A helicopter was generated in a Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD) in an effort to validate its analytical capabilities for modeling a current advanced Army helicopter. The initial phase of the effort involved the generation of CAMRAD input files necessary for the complete aerodynamic, structural, and dynamic definition of the production AH-64A helicopter. The input files were checked by making comparisons of CAMRAD full helicopter trim and main rotor blade natural frequency predictions with those of full helicopter trim program, Blade Element Trim (BETRIM), and dynamic analysis code, Dynamic Analysis Research Tool (DART), respectively. The main thrust concerned the application of the AH-64A CAMRAD model thus developed and verified for main rotor blade structural loads predictions and comparison with DART analytical results. The investigation provided insight not only into the usefulness of CAMRAD for the AH-64A performance and dynamics prediction, but also into the limitations of the program for modeling advanced rotor and fuselage systems. The model development effort is discussed, the results of the CAMRAD correlation studies presented, and some general conclusions are offered on the applicability of CAMRAD for rotor aeroelastic loads prediction for current and future rotorcraft configurations.

  17. Functional Conservation and Divergence of Four Ginger AP1/AGL9 MADS–Box Genes Revealed by Analysis of Their Expression and Protein–Protein Interaction, and Ectopic Expression of AhFUL Gene in Arabidopsis

    PubMed Central

    Song, Juanjuan; Sun, Wei; Xia, Kuaifei; Liao, Jingping; Zhang, Mingyong

    2014-01-01

    Alpinia genus are known generally as ginger–lilies for showy flowers in the ginger family, Zingiberaceae, and their floral morphology diverges from typical monocotyledon flowers. However, little is known about the functions of ginger MADS–box genes in floral identity. In this study, four AP1/AGL9 MADS–box genes were cloned from Alpinia hainanensis, and protein–protein interactions (PPIs) and roles of the four genes in floral homeotic conversion and in floral evolution are surveyed for the first time. AhFUL is clustered to the AP1lineage, AhSEP4 and AhSEP3b to the SEP lineage, and AhAGL6–like to the AGL6 lineage. The four genes showed conserved and divergent expression patterns, and their encoded proteins were localized in the nucleus. Seven combinations of PPI (AhFUL–AhSEP4, AhFUL–AhAGL6–like, AhFUL–AhSEP3b, AhSEP4–AhAGL6–like, AhSEP4–AhSEP3b, AhAGL6–like–AhSEP3b, and AhSEP3b–AhSEP3b) were detected, and the PPI patterns in the AP1/AGL9 lineage revealed that five of the 10 possible combinations are conserved and three are variable, while conclusions cannot yet be made regarding the other two. Ectopic expression of AhFUL in Arabidopsis thaliana led to early flowering and floral organ homeotic conversion to sepal–like or leaf–like. Therefore, we conclude that the four A. hainanensis AP1/AGL9 genes show functional conservation and divergence in the floral identity from other MADS–box genes. PMID:25461565

  18. Maneuvering Rotorcraft Noise Prediction: A New Code for a New Problem

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Bres, Guillaume A.; Perez, Guillaume; Jones, Henry E.

    2002-01-01

    This paper presents the unique aspects of the development of an entirely new maneuver noise prediction code called PSU-WOPWOP. The main focus of the code is the aeroacoustic aspects of the maneuver noise problem, when the aeromechanical input data are provided (namely aircraft and blade motion, blade airloads). The PSU-WOPWOP noise prediction capability was developed for rotors in steady and transient maneuvering flight. Featuring an object-oriented design, the code allows great flexibility for complex rotor configuration and motion (including multiple rotors and full aircraft motion). The relative locations and number of hinges, flexures, and body motions can be arbitrarily specified to match the any specific rotorcraft. An analysis of algorithm efficiency is performed for maneuver noise prediction along with a description of the tradeoffs made specifically for the maneuvering noise problem. Noise predictions for the main rotor of a rotorcraft in steady descent, transient (arrested) descent, hover and a mild "pop-up" maneuver are demonstrated.

  19. Cassini Orbit Trim Maneuvers at Saturn - Overview of Attitude Control Flight Operations

    NASA Technical Reports Server (NTRS)

    Burk, Thomas A.

    2011-01-01

    The Cassini spacecraft has been in orbit around Saturn since July 1, 2004. To remain on the planned trajectory which maximizes science data return, Cassini must perform orbit trim maneuvers using either its main engine or its reaction control system thrusters. Over 200 maneuvers have been executed on the spacecraft since arrival at Saturn. To improve performance and maintain spacecraft health, changes have been made in maneuver design command placement, in accelerometer scale factor, and in the pre-aim vector used to align the engine gimbal actuator prior to main engine burn ignition. These and other changes have improved maneuver performance execution errors significantly since 2004. A strategy has been developed to decide whether a main engine maneuver should be performed, or whether the maneuver can be executed using the reaction control system.

  20. Using the Two-Burn Escape Maneuver for Fast Transfers in the Solar System and Beyond

    NASA Technical Reports Server (NTRS)

    Adams, Robert B.; Richardson, Georgia A.

    2010-01-01

    The two-burn maneuver to escape the gravitational pull of a central body is described. The maneuver, originally suggested by Hermann Oberth, improves efficiency considerably for a wide range of missions of interest in space exploration and scientific investigation. A clear delineation of when the maneuver is more effective is given, as are methods to extract the most advantage when using the maneuver. Some examples are given of how this maneuver can enable exploration of the outer solar system, near interstellar space, and crewed missions to Mars and beyond. The maneuver has the potential to halve the required infrastructure associated with a crewed mission to Mars and achieve increased solar escape velocities with existing spacecraft technologies.

  1. A Semi-Empirical Noise Modeling Method for Helicopter Maneuvering Flight Operations

    NASA Technical Reports Server (NTRS)

    Greenwood, Eric; Schmitz, Fredric; Sickenberger, Richard D.

    2012-01-01

    A new model for Blade-Vortex Interaction noise generation during maneuvering flight is developed in this paper. Acoustic and performance data from both flight and wind tunnels are used to derive a non-dimensional and analytical performance/acoustic model that describes BVI noise in steady flight. The model is extended to transient maneuvering flight (pure pitch and roll transients) by using quasisteady assumptions throughout the prescribed maneuvers. Ground noise measurements, taken during maneuvering flight of a Bell 206B helicopter, show that many of the noise radiation details are captured. The result is a computationally efficient Blade-Vortex Interaction noise model with sufficient accuracy to account for transient maneuvering flight. The code can be run in real time to predict transient maneuver noise and is suitable for use in an acoustic mission-planning tool.

  2. Baroreceptor reflex during forced expiratory maneuvers in individuals with chronic spinal cord injury.

    PubMed

    Legg Ditterline, Bonnie E; Aslan, Sevda C; Randall, David C; Harkema, Susan J; Ovechkin, Alexander V

    2016-07-15

    Pulmonary and cardiovascular dysfunctions are leading causes of morbidity and mortality in patients with chronic Spinal Cord Injury (SCI). Impaired respiratory motor function and decreased Baroreflex Sensitivity (BS) are predictors for the development of cardiopulmonary disease. This observational case-controlled clinical study was undertaken to investigate if respiratory motor control deficits in individuals with SCI affect their ability to perform the Valsalva maneuver, and to determine if a sustained Maximum Expiratory Pressure (MEP) effort can serve as an acceptable maneuver for determination of the BS in the event that the Valsalva maneuver cannot be performed. The BS outcomes (ms/mmHg) were obtained using continuous beat-to-beat arterial blood pressure (BP) and heart rate (HR) recordings during Valsalva or MEP maneuvers in thirty nine individuals with chronic C3-T12 SCI. Twenty one participants (54%) reported signs of intolerance during the Valsalva maneuver and only 15 individuals (39%) were able to complete this task. Cervical level of injury was a significant risk factor (p=0.001) for failing to complete the Valsalva maneuver, and motor-complete injury was a significant risk factor for symptoms of intolerance (p=0.04). Twenty eight participants (72%) were able to perform the MEP maneuver; the other 11 participants failed to exceed the standard airway pressure threshold of 27cm H2O. Neither level nor completeness of injury were significant risk factors for failure of MEP maneuver. When the required airway pressure was sustained, there were no significant differences between BS outcomes obtained during Valsalva and MEP maneuvers. The results of this study indicate that individuals with high-level and motor-complete SCI are at increased risk of not completing the Valsalva maneuver and that baroreflex-mediated responses can be evaluated by using sustained MEP maneuver when the Valsalva maneuver cannot be performed. PMID:27137412

  3. Computing and Visualizing Reachable Volumes for Maneuvering Satellites

    SciTech Connect

    Jiang, M; de Vries, W H; Pertica, A J; Olivier, S S

    2011-09-11

    Detecting and predicting maneuvering satellites is an important problem for Space Situational Awareness. The spatial envelope of all possible locations within reach of such a maneuvering satellite is known as the Reachable Volume (RV). As soon as custody of a satellite is lost, calculating the RV and its subsequent time evolution is a critical component in the rapid recovery of the satellite. In this paper, we present a Monte Carlo approach to computing the RV for a given object. Essentially, our approach samples all possible trajectories by randomizing thrust-vectors, thrust magnitudes and time of burn. At any given instance, the distribution of the 'point-cloud' of the virtual particles defines the RV. For short orbital time-scales, the temporal evolution of the point-cloud can result in complex, multi-reentrant manifolds. Visualization plays an important role in gaining insight and understanding into this complex and evolving manifold. In the second part of this paper, we focus on how to effectively visualize the large number of virtual trajectories and the computed RV. We present a real-time out-of-core rendering technique for visualizing the large number of virtual trajectories. We also examine different techniques for visualizing the computed volume of probability density distribution, including volume slicing, convex hull and isosurfacing. We compare and contrast these techniques in terms of computational cost and visualization effectiveness, and describe the main implementation issues encountered during our development process. Finally, we will present some of the results from our end-to-end system for computing and visualizing RVs using examples of maneuvering satellites.

  4. Volunteer kinematics and reaction in lateral emergency maneuver tests.

    PubMed

    Rooij, L van; Elrofai, H; Philippens, M M G M; Daanen, H A M

    2013-11-01

    It is important to understand human kinematics and muscle activation patterns in emergency maneuvers for the design of safety systems and for the further development of human models. The objective of this study was to quantify kinematic behavior and muscle activation in simulated steering tests in several realistic conditions. In total 108 tests were performed with 10 volunteers undergoing purely lateral maneuvers at 5 m/s^2 deceleration or simulated lane change maneuvers at 5 m/s^2 peak acceleration and peak yaw velocity of 25 °/s. Test subjects were seated on a rigid seat and restrained by a 4-point belt with retractor. Driver subjects were instructed to be relaxed or braced and to hold the steering wheel while passenger subjects were instructed to put their hands on their thighs. Subjects were instrumented with photo markers that were tracked with 3D high- speed stereo cameras and with electromyography (EMG) electrodes on 8 muscles. Corridors of head displacement, pitch and roll and displacement of T1, shoulder, elbow, hand and knee were created representing mean response and standard deviation of all subjects. In lane change tests for the passenger configuration significant differences were observed in mean peak of head left lateral displacement between the relaxed and the braced volunteers, i.e. 171 mm (σ=58, n=21) versus 121 mm (σ=46, n=17), respectively. Sitting in a relaxed position led to significantly lower muscle activity of the neck muscles. It was concluded that significantly more upper body motion and lower muscle activity was observed for relaxed subjects than for braced subjects. PMID:24435737

  5. Command shaping for residual vibration free crane maneuvers

    NASA Astrophysics Data System (ADS)

    Parker, G. G.; Petterson, B.; Dohrmann, C.; Robinett, R. D.

    1995-01-01

    Cranes used in the construction and transportation industries are generally devices with multiple degrees of freedom including variable load-line length, variable jib length (usually via a trolley), and variable boom angles. Point-to-point payload maneuvers using cranes are performed so as not to excite the spherical pendulum modes of their cable and payload assemblies. Typically, these pendulum modes, although time-varying, exhibit low frequencies. Current crane maneuvers are therefore performed slowly contributing to high construction and transportation costs. This investigation details a general method for applying command shaping to various multiple degree of freedom cranes such that the payload moves to a specified point without residual oscillation. A dynamic programming method is used for general command shaping for optimal maneuvers. Computationally, the dynamic programming approach requires order M calculations to arrive at a solution, where M is the number of discretizations of the input commands. This feature is exploited for the crane command shaping problem allowing for rapid calculation of command histories. Fast generation of commands is a necessity for practical use of command shaping for the applications described in this work. These results are compared to near-optimal solutions where the commands are linear combinations of acceleration pulse basis functions. The pulse shape is required due to hardware requirements. The weights on the basis functions are chosen as the solution to a parameter optimization problem solved using a Recursive Quadratic Programming technique. Simulation results and experimental verification for a variable load-line length rotary crane are presented using both design procedures.

  6. Simulation of upwind maneuvering of a sailing yacht

    NASA Astrophysics Data System (ADS)

    Harris, Daniel Hartrick

    A time domain maneuvering simulation of an IACC class yacht suitable for the analysis of unsteady upwind sailing including tacking is presented. The simulation considers motions in six degrees of freedom. The hydrodynamic and aerodynamic loads are calculated primarily with unsteady potential theory supplemented by empirical viscous models. The hydrodynamic model includes the effects of incident waves. Control of the rudder is provided by a simple rate feedback autopilot which is augmented with open loop additions to mimic human steering. The hydrodynamic models are based on the superposition of force components. These components fall into two groups, those which the yacht will experience in calm water, and those due to incident waves. The calm water loads are further divided into zero Froude number, or "double body" maneuvering loads, hydrostatic loads, gravitational loads, free surface radiation loads, and viscous/residual loads. The maneuvering loads are calculated with an unsteady panel code which treats the instantaneous geometry of the yacht below the undisturbed free surface. The free surface radiation loads are calculated via convolution of impulse response functions derived from seakeeping strip theory. The viscous/residual loads are based upon empirical estimates. The aerodynamic model consists primarily of a database of steady state sail coefficients. These coefficients treat the individual contributions to the total sail force of a number of chordwise strips on both the main and jib. Dynamic effects are modeled by using the instantaneous incident wind velocity and direction as the independent variables for the sail load contribution of each strip. The sail coefficient database was calculated numerically with potential methods and simple empirical viscous corrections. Additional aerodynamic load calculations are made to determine the parasitic contributions of the rig and hull. Validation studies compare the steady sailing hydro and aerodynamic loads

  7. Command shaping for residual vibration free crane maneuvers

    SciTech Connect

    Parker, G.G.; Petterson, B.; Dohrmann, C.; Robinett, R.D.

    1995-07-01

    Cranes used in the construction and transportation industries are generally devices with multiple degrees of freedom including variable load-line length, variable jib length (usually via a trolley), and variable boom angles. Point-to-point payload maneuvers using cranes are performed so as not to excite the spherical pendulum modes of their cable and payload assemblies. Typically, these pendulum modes, although time-varying, exhibit low frequencies. Current crane maneuvers are therefore performed slowly contributing to high construction and transportation costs. This investigation details a general method for applying command shaping to various multiple degree of freedom cranes such that the payload moves to a specified point without residual oscillation. A dynamic programming method is used for general command shaping for optimal maneuvers. Computationally, the dynamic programming approach requires order M calculations to arrive at a solution, where M is the number of discretizations of the input commands. This feature is exploited for the crane command shaping problem allowing for rapid calculation of command histories. Fast generation of commands is a necessity for practical use of command shaping for the applications described in this work. These results are compared to near-optimal solutions where the commands are linear combinations of acceleration pulse basis functions. The pulse shape is required due to hardware requirements. The weights on the basis functions are chosen as the solution to a parameter optimization problem solved using a Recursive Quadratic Programming technique. Simulation results and experimental verification for a variable load-line length rotary crane are presented using both design procedures.

  8. The Orbital Maneuvering Vehicle Training Facility visual system concept

    NASA Technical Reports Server (NTRS)

    Williams, Keith

    1989-01-01

    The purpose of the Orbital Maneuvering Vehicle (OMV) Training Facility (OTF) is to provide effective training for OMV pilots. A critical part of the training environment is the Visual System, which will simulate the video scenes produced by the OMV Closed-Circuit Television (CCTV) system. The simulation will include camera models, dynamic target models, moving appendages, and scene degradation due to the compression/decompression of video signal. Video system malfunctions will also be provided to ensure that the pilot is ready to meet all challenges the real-world might provide. One possible visual system configuration for the training facility that will meet existing requirements is described.

  9. OMV: A simplified mathematical model of the orbital maneuvering vehicle

    NASA Technical Reports Server (NTRS)

    Teoh, W.

    1984-01-01

    A model of the orbital maneuvering vehicle (OMV) is presented which contains several simplications. A set of hand controller signals may be used to control the motion of the OMV. Model verification is carried out using a sequence of tests. The dynamic variables generated by the model are compared, whenever possible, with the corresponding analytical variables. The results of the tests show conclusively that the present model is behaving correctly. Further, this model interfaces properly with the state vector transformation module (SVX) developed previously. Correct command sentence sequences are generated by the OMV and and SVX system, and these command sequences can be used to drive the flat floor simulation system at MSFC.

  10. Space Shuttle OMS engine valve technology. [Orbital Maneuvering System

    NASA Technical Reports Server (NTRS)

    Wichmann, H.

    1974-01-01

    Valve technology program to determine shutoff valve concepts suitable for the Orbital Maneuvering System (OMS) engine of the Space Shuttle. The tradeoff studies selected the electric torque motor operated dual poppet and ball valves as the most desirable valve concepts for the OMS Engine Shutoff Valve. A prototype of one of these concepts was built and subjected to a design verification program. A number of unique features were designed to include the required contamination insensitivity, operating fluid compatibility, decontamination capability, minimum maintenance requirement and long service life capability.

  11. Sequential Probability Ratio Test for Collision Avoidance Maneuver Decisions

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell; Markley, F. Landis

    2010-01-01

    When facing a conjunction between space objects, decision makers must chose whether to maneuver for collision avoidance or not. We apply a well-known decision procedure, the sequential probability ratio test, to this problem. We propose two approaches to the problem solution, one based on a frequentist method, and the other on a Bayesian method. The frequentist method does not require any prior knowledge concerning the conjunction, while the Bayesian method assumes knowledge of prior probability densities. Our results show that both methods achieve desired missed detection rates, but the frequentist method's false alarm performance is inferior to the Bayesian method's

  12. Safe Maneuvering Envelope Estimation Based on a Physical Approach

    NASA Technical Reports Server (NTRS)

    Lombaerts, Thomas J. J.; Schuet, Stefan R.; Wheeler, Kevin R.; Acosta, Diana; Kaneshige, John T.

    2013-01-01

    This paper discusses a computationally efficient algorithm for estimating the safe maneuvering envelope of damaged aircraft. The algorithm performs a robust reachability analysis through an optimal control formulation while making use of time scale separation and taking into account uncertainties in the aerodynamic derivatives. This approach differs from others since it is physically inspired. This more transparent approach allows interpreting data in each step, and it is assumed that these physical models based upon flight dynamics theory will therefore facilitate certification for future real life applications.

  13. STS-100 MS Parazynski practices maneuvers on a simulator

    NASA Technical Reports Server (NTRS)

    2001-01-01

    KENNEDY SPACE CENTER, Fla. - STS-100 Mission Specialist Scott E. Parazynski practices maneuvers on a simulator for installing the Canadian-built Space Station Remote Manipulator System (SSRMS). He and Mission Specialist Chris A. Hadfield will undertake two spacewalks to install the SSRMS. The 11-day mission to the International Space Station will also deliver the Multi-Purpose Logistics Module Raffaello, carrying six system racks and two storage racks for the U.S. Lab. Liftoff on mission STS-100 is scheduled at 2:41 p.m. EDT April 19.

  14. STS-100 MS Hadfield practices maneuvers on a simulator

    NASA Technical Reports Server (NTRS)

    2001-01-01

    KENNEDY SPACE CENTER, Fla. - STS-100 Mission Specialist Chris A. Hadfield, with the Canadian Space Agency, practices maneuvers on a simulator for installing the Canadian-built Space Station Remote Manipulator System (SSRMS). He and Mission Specialist Scott E. Parazynski will undertake two spacewalks to install the SSRMS. The 11-day mission to the International Space Station will also deliver the Multi-Purpose Logistics Module Raffaello, carrying six system racks and two storage racks for the U.S. Lab. Liftoff on mission STS-100 is scheduled at 2:41 p.m. EDT April 19.

  15. Manned maneuvering unit - A space platform support system

    NASA Technical Reports Server (NTRS)

    Whitsett, C. E., Jr.; Lenda, J. A.; Josephson, J. T.

    1978-01-01

    The assembly and evaluation of large space platforms in low earth orbit will become practical in the Shuttle era. Extravehicular crewmembers, equipped with manned maneuvering units (MMUs), will play a vital role in the construction and checkout of these platforms. The MMU is a propulsive backpack with mobility extending the crew's visual, mental, and manipulative capabilities beyond the cabin to on-the-spot assembly and maintenance operations. Previous MMU experience is reviewed, Shuttle MMU design features related to space platform support are described, and the use of the MMU for specific construction and assembly tasks is illustrated.

  16. Optimal cooperative CubeSat maneuvers obtained through parallel computing

    NASA Astrophysics Data System (ADS)

    Ghosh, Alexander; Coverstone, Victoria

    2015-02-01

    CubeSats, the class of small standardized satellites, are quickly becoming a prevalent scientific research tool. The desire to perform ambitious missions using multiple CubeSats will lead to innovations in thruster technology and will require new tools for the development of cooperative trajectory planning. To meet this need, a new software tool was created to compute propellant-minimizing maneuvers for two or more CubeSats. By including parallelization techniques, this tool is shown to run significantly faster than its serial counterpart.

  17. Pseudosteady-state analysis of nonlinear aircraft maneuvers

    NASA Technical Reports Server (NTRS)

    Young, J. W.; Schy, A. A.; Johnson, K. G.

    1980-01-01

    An analytical method was developed for studying the combined effects of rotational coupling and nonlinear aerodynamics on aircraft response for specified control inputs. The method involves the simultaneous solution of two nonlinear equations which are functions of angle attack, roll rate, and control inputs. The method was applied to a number of maneuvers for a fighter-type aircraft. Time history responses verified the usefulness of the analysis for predicting a variety of response characteristics caused by interacting nonlinear aerodynamic and inertial effects, including spin conditions.

  18. Flight simulator fidelity assessment in a rotorcraft lateral translation maneuver

    NASA Technical Reports Server (NTRS)

    Hess, R. A.; Malsbury, T.; Atencio, A., Jr.

    1992-01-01

    A model-based methodology for assessing flight simulator fidelity in closed-loop fashion is exercised in analyzing a rotorcraft low-altitude maneuver for which flight test and simulation results were available. The addition of a handling qualities sensitivity function to a previously developed model-based assessment criteria allows an analytical comparison of both performance and handling qualities between simulation and flight test. Model predictions regarding the existence of simulator fidelity problems are corroborated by experiment. The modeling approach is used to assess analytically the effects of modifying simulator characteristics on simulator fidelity.

  19. Development of control laws for a flight test maneuver autopilot for an F-15 aircraft

    NASA Technical Reports Server (NTRS)

    Alag, G. S.; Duke, E. L.

    1985-01-01

    An autopilot can be used to provide precise control to meet the demanding requirements of flight research maneuvers with high-performance aircraft. The development of control laws within the context of flight test maneuver requirements is discussed. The control laws are developed using eigensystem assignment and command generator tracking. The eigenvalues and eigenvectors are chosen to provide the necessary handling qualities, while the command generator tracking enables the tracking of a specified state during the maneuver. The effectiveness of the control laws is illustrated by their application to an F-15 aircraft to ensure acceptable aircraft performance during a maneuver.

  20. Study on zigzag maneuver characteristics of V-U very large crude oil (VLCC) tankers

    NASA Astrophysics Data System (ADS)

    Jaswar, Maimun, A.; Wahid, M. A.; Priyanto, A.; Zamani, Pauzi, Saman

    2012-06-01

    The Department of Marine Technology at the Faculty of Mechanical Engineering, University Teknologi Malaysia has recently developed an Ship Maneuverability tool which intends to upgrade student's level understanding the application of fluid dynamic on interaction between hull, propeller, and rudder during maneuvering. This paper discusses zigzag maneuver for conventional Very Large Crude Oil (VLCC) ships with the same principal dimensions but different stern flame shape. 10/10 zigzag maneuver characteristics of U and V types of VLCC ships are investigated. Simulation results for U-type show a good agreement with the experimental data, but V-type not good agreement with experimental one. Further study on zigzag maneuver characteristics are required.

  1. A fixed H-infinity controller for a supermaneuverable fighter performing the Herbst maneuver

    NASA Technical Reports Server (NTRS)

    Chiang, R. Y.; Safonov, M. G.; Haiges, K.; Madden, K.; Tekawy, J.

    1993-01-01

    This paper presents an H-infinity flight control system design case study for a supermaneuverable fighter flying the Herbst maneuver. The Herbst maneuver presents an especially challenging flight control problem because of its large ranges of airspeed, angle of attack and angular rates. A fixed H-infinity controller has been developed via the mixed-sensitivity problem formulation for 20 linearized models representing the maneuver. Both linear and nonlinear full model evaluations indicate that this single H-infinity controller together with a fixed LQR inner loop feedback have achieved 'robust stability' and 'robust performance' for the entire maneuver without gain scheduling.

  2. Development of a Smooth Trajectory Maneuver Method to Accommodate the Ares I Flight Control Constraints

    NASA Technical Reports Server (NTRS)

    Pinson, Robin M.; Schmitt, Terri L.; Hanson, John M.

    2008-01-01

    Six degree-of-freedom (DOF) launch vehicle trajectories are designed to follow an optimized 3-DOF reference trajectory. A vehicle has a finite amount of control power that it can allocate to performing maneuvers. Therefore, the 3-DOF trajectory must be designed to refrain from using 100% of the allowable control capability to perform maneuvers, saving control power for handling off-nominal conditions, wind gusts and other perturbations. During the Ares I trajectory analysis, two maneuvers were found to be hard for the control system to implement; a roll maneuver prior to the gravity turn and an angle of attack maneuver immediately after the J-2X engine start-up. It was decided to develop an approach for creating smooth maneuvers in the optimized reference trajectories that accounts for the thrust available from the engines. A feature of this method is that no additional angular velocity in the direction of the maneuver has been added to the vehicle after the maneuver completion. This paper discusses the equations behind these new maneuvers and their implementation into the Ares I trajectory design cycle. Also discussed is a possible extension to adjusting closed-loop guidance.

  3. Characterization of Peanut Germin-Like Proteins, AhGLPs in Plant Development and Defense

    PubMed Central

    Wang, Tong; Chen, Xiaoping; Zhu, Fanghe; Li, Haifen; Li, Ling; Yang, Qingli; Chi, Xiaoyuan; Yu, Shanlin; Liang, Xuanqiang

    2013-01-01

    Background Germin-like superfamily members are ubiquitously expressed in various plant species and play important roles in plant development and defense. Although several GLPs have been identified in peanut (Arachis hypogaea L.), their roles in development and defense remain unknown. In this research, we study the spatiotemporal expression of AhGLPs in peanut and their functions in plant defense. Results We have identified three new AhGLP members (AhGLP3b, AhGLP5b and AhGLP7b) that have distinct but very closely related DNA sequences. The spatial and temporal expression profiles revealed that each peanut GLP gene has its distinct expression pattern in various tissues and developmental stages. This suggests that these genes all have their distinct roles in peanut development. Subcellular location analysis demonstrated that AhGLP2 and 5 undergo a protein transport process after synthesis. The expression of all AhGLPs increased in responding to Aspergillus flavus infection, suggesting AhGLPs' ubiquitous roles in defense to A. flavus. Each AhGLP gene had its unique response to various abiotic stresses (including salt, H2O2 stress and wound), biotic stresses (including leaf spot, mosaic and rust) and plant hormone stimulations (including SA and ABA treatments). These results indicate that AhGLPs have their distinct roles in plant defense. Moreover, in vivo study of AhGLP transgenic Arabidopsis showed that both AhGLP2 and 3 had salt tolerance, which made transgenic Arabidopsis grow well under 100 mM NaCl stress. Conclusions For the first time, our study analyzes the AhGLP gene expression profiles in peanut and reveals their roles under various stresses. These results provide an insight into the developmental and defensive roles of GLP gene family in peanut. PMID:23626720

  4. Calorimetry of 25 Ah lithium/thionyl chloride cells

    NASA Technical Reports Server (NTRS)

    Johnson, C. J.; Dawson, S.

    1991-01-01

    Heat flow measurements of 25-Ah lithium thionyl chloride cells provided a method to calculate an effective thermal potential, E(TP) of 3.907 V. The calculation is useful to determine specific heat generation of this cell chemistry and design. The E(TP) value includes heat generation by electrochemical cell reactions, competitive chemical reactions, and resistance heating at the tabs, connectors, and leads. Heat flow was measured while applying electrical loads to the cell in an isothermal calorimeter set at 0, 20, and 60 C.

  5. A 65 Ah rechargeable lithium molybdenum disulfide battery

    NASA Technical Reports Server (NTRS)

    Brandt, K.

    1986-01-01

    A rechargeable lithium molybdenum disulfide battery which has a number of superior performance characteristics which includes a high energy density, a high power density, and a long charge retention time was developed. The first cell sizes developed included a C size cell and an AA size cell. Over the last two years, a project to demonstrate the feasibility of the scale up to this technology to a BC size cell with 65 Ah capacity was undertaken. The objective was to develop, build, and test a .6 kWh storage battery consisting of 6 BC cells in series.

  6. Large-angle slewing maneuvers for flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Chun, Hon M.; Turner, James D.

    1988-01-01

    A new class of closed-form solutions for finite-time linear-quadratic optimal control problems is presented. The solutions involve Potter's solution for the differential matrix Riccati equation, which assumes the form of a steady-state plus transient term. Illustrative examples are presented which show that the new solutions are more computationally efficient than alternative solutions based on the state transition matrix. As an application of the closed-form solutions, the neighboring extremal path problem is presented for a spacecraft retargeting maneuver where a perturbed plant with off-nominal boundary conditions now follows a neighboring optimal trajectory. The perturbation feedback approach is further applied to three-dimensional slewing maneuvers of large flexible spacecraft. For this problem, the nominal solution is the optimal three-dimensional rigid body slew. The perturbation feedback then limits the deviations from this nominal solution due to the flexible body effects. The use of frequency shaping in both the nominal and perturbation feedback formulations reduces the excitation of high-frequency unmodeled modes. A modified Kalman filter is presented for estimating the plant states.

  7. Robust Aerial Object Tracking in High Dynamic Flight Maneuvers

    NASA Astrophysics Data System (ADS)

    Nussberger, A.; Grabner, H.; van Gool, L.

    2015-08-01

    Integrating drones into the civil airspace is one of the biggest challenges for civil aviation, responsible authorities and involved com- panies around the world in the upcoming years. For a full integration into non-segregated airspace such a system has to provide the capability to automatically detect and avoid other airspace users. Electro-optical cameras have proven to be an adequate sensor to detect all types of aerial objects, especially for smaller ones such as gliders or paragliders. Robust detection and tracking of approaching traffic on a potential collision course is the key component for a successful avoidance maneuver. In this paper we focus on the aerial object tracking during dynamic flight maneuvers of the own-ship where accurate attitude information corresponding to the camera images is essential. Because the 'detect and avoid' functionality typically extends existing autopilot systems the received attitude measurements have unknown delays and dynamics. We present an efficient method to calculate the angular rates from a multi camera rig which we fuse with the delayed attitude measurements. This allows for estimating accurate absolute attitude angles for every camera frame. The proposed method is further integrated into an aerial object tracking framework. A detailed evaluation of the pipeline on real collision encounter scenarios shows that the multi camera rig based attitude estimation enables the correct tracking of approaching traffic during dynamic flight, at which the tracking framework previously failed.

  8. Independent Orbiter Assessment (IOA): Analysis of the orbital maneuvering system

    NASA Technical Reports Server (NTRS)

    Prust, C. D.; Paul, D. J.; Burkemper, V. J.

    1987-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Orbital Maneuvering System (OMS) hardware are documented. The OMS provides the thrust to perform orbit insertion, orbit circularization, orbit transfer, rendezvous, and deorbit. The OMS is housed in two independent pods located one on each side of the tail and consists of the following subsystems: Helium Pressurization; Propellant Storage and Distribution; Orbital Maneuvering Engine; and Electrical Power Distribution and Control. The IOA analysis process utilized available OMS hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluted and analyzed for possible failure modes and effects. Criticality was asigned based upon the severity of the effect for each failure mode.

  9. SRMS Assisted Docking and Undocking for the Orbiter Repair Maneuver

    NASA Technical Reports Server (NTRS)

    Quiocho, Leslie J.; Briscoe, Timothy J.; Schliesing, John A.; Braman, Julia M.

    2005-01-01

    As part of the Orbiter Repair Maneuver (ORM) planned for Return to Flight (RTF) operations, the Shuttle Remote Manipulator System (SRMS) must undock the Orbiter, maneuver it through a complex trajectory at extremely low rates, present it to an EVA crewman at the end of the Space Station Remote Manipulator System to perform the Thermal Protection System (TPS) repair, and then retrace back through the trajectory to dock the Orbiter with the Orbiter Docking System (ODs). The initial and final segments of this operation involve the interaction between the SRMS, ISS, Orbiter and ODs. This paper first provides an overview of the Monte-Carlo screening analysis for the installation (both nominal and contingency), including the variation of separation distance, misalignment conditions, SRMS joint/brake parameter characteristics, and PRCS jet combinations and corresponding thrust durations. The resulting 'optimum' solution is presented based on trade studies between predicted capture success and integrated system loads. This paper then discusses the upgrades to the APAS math model associated with the new SRMS assisted undocking technique and reviews simulation results for various options investigated for either the active and passive separation of the ISS from the Orbiter.

  10. Control and dynamics of a flexible spacecraft during stationkeeping maneuvers

    NASA Technical Reports Server (NTRS)

    Liu, D.; Yocum, J.; Kang, D. S.

    1991-01-01

    A case study of a spacecraft having flexible solar arrays is presented. A stationkeeping attitude control mode using both earth and rate gyro reference signals and a flexible vehicle dynamics modeling and implementation is discussed. The control system is designed to achieve both pointing accuracy and structural mode stability during stationkeeping maneuvers. Reduction of structural mode interactions over the entire mode duration is presented. The control mode using a discrete time observer structure is described to show the convergence of the spacecraft attitude transients during Delta-V thrusting maneuvers without preloading thrusting bias to the onboard control processor. The simulation performance using the three axis, body stabilized nonlinear dynamics is provided. The details of a five body dynamics model are discussed. The spacecraft is modeled as a central rigid body having cantilevered flexible antennas, a pair of flexible articulated solar arrays, and to gimballed momentum wheels. The vehicle is free to undergo unrestricted rotations and translations relative to inertial space. A direct implementation of the equations of motion is compared to an indirect implementation that uses a symbolic manipulation software to generate rigid body equations.

  11. Muscular Control of Turning and Maneuvering in Jellyfish Bells

    NASA Astrophysics Data System (ADS)

    Hoover, Alexander; Miller, Laura; Griffith, Boyce

    2014-11-01

    Jellyfish represent one of the earliest and simplest examples of swimming by a macroscopic organism. Contractions of an elastic bell that expels water are driven by coronal swimming muscles. The re-expansion of the bell is passively driven by stored elastic energy. A current question in jellyfish propulsion is how the underlying neuromuscular organization of their bell allows for maneuvering. Using an immersed boundary framework, we will examine the mechanics of swimming by incorporating material models that are informed by the musculature present in jellyfish into a model of the elastic jellyfish bell in three dimensions. The fully-coupled fluid structure interaction problem is solved using an adaptive and parallelized version of the immersed boundary method (IBAMR). We then use this model to understand how variability in the muscular activation patterns allows for complicated swimming behavior, such as steering. We will compare the results of the simulations with the actual turning maneuvers of several species of jellyfish. Numerical flow fields will also be compared to those produced by actual jellyfish using particle image velocimetry (PIV).

  12. The Valsalva maneuver and Alzheimer's disease: is there a link?

    PubMed

    Wostyn, Peter; Audenaert, Kurt; De Deyn, Peter Paul

    2009-02-01

    Recent research findings provide evidence for Alzheimer's disease-related changes in brain diseases, such as normal pressure hydrocephalus and traumatic brain injury, and in glaucoma at the level of the retinal ganglion cells. This is a group of diseases that affect central nervous system tissue and are characterized by elevation of intracranial or intraocular pressure and/or local shear stress and strain. This strengthens the possibility that Alzheimer-type changes in these diseases may result at least in part from exposure of central nervous system tissue to elevated mechanical load. As activities or diseases with significant Valsalva effort can generate increased intracranial pressures, we hypothesize that individuals who frequently perform strong Valsalva maneuvers (e.g., long hours of repetitive heavy lifting, sequences of blows during the playing of a wind instrument, forceful and repetitive cough, bearing-down efforts during parturition) may be more susceptible to developing Alzheimer's disease. In this paper, we discuss three hypotheses about the mechanisms by which extensive use of the Valsalva maneuver might contribute to the neuropathogenesis of Alzheimer's disease: via mechanical stress-induced events in the hippocampus and/or via changes in the secretory process of the choroid plexus and/or via hemodynamic changes in cerebral blood flow. If confirmed, this hypothesis could have implications in clinical practice. PMID:19199876

  13. Valsalva maneuver: Insights into baroreflex modulation of human sympathetic activity

    NASA Technical Reports Server (NTRS)

    Smith, Michael L.; Eckberg, Dwain L.; Fritsch, Janice M.; Beightol, Larry A.; Ellenbogen, Kenneth A.

    1991-01-01

    Valsalva's maneuver, voluntary forced expiration against a closed glottis, is a well-characterized research tool, used to assess the integrity of human autonomic cardiovascular control. Valsalva straining provokes a stereotyped succession of alternating positive and negative arterial pressure and heart rate changes mediated in part by arterial baroreceptors. Arterial pressure changes result primarily from fluctuating levels of venous return to the heart and changes of sympathetic nerve activity. Muscle sympathetic activity was measured directly in nine volunteers to explore quantitatively the relation between arterial pressure and human sympathetic outflow during pressure transients provoked by controlled graded Valsalva maneuvers. Our results underscore several properties of sympathetic regulation during Valsalva straining. First, muscle sympathetic nerve activity changes as a mirror image of changes in arterial pressure. Second, the magnitude of sympathetic augmentation during Valsalva straining predicts phase 4 arterial pressure elevations. Third, post-Valsalva sympathetic inhibition persists beyond the return of arterial and right atrial pressures to baseline levels which reflects an alteration of the normal relation between arterial pressure and muscle sympathetic activity. Therefore, Valsalva straining may have some utility for investigating changes of reflex control of sympathetic activity after space flight; however, measurement of beat-to-beat arterial pressure is essential for this use. The utility of this technique in microgravity can not be determined from these data. Further investigations are necessary to determine whether these relations are affected by the expansion of intrathoracic blood volume associated with microgravity.

  14. Propulsive Maneuver Design for the 2007 Mars Phoenix Lander Mission

    NASA Technical Reports Server (NTRS)

    Raofi, Behzad; Bhat, Ramachandra S.; Helfrich, Cliff

    2008-01-01

    On May 25, 2008, the Mars Phoenix Lander (PHX) successfully landed in the northern planes of Mars in order to continue and complement NASA's "follow the water" theme as its predecessor Mars missions, such as Mars Odyssey (ODY) and Mars Exploration Rovers, have done in recent years. Instruments on the lander, through a robotic arm able to deliver soil samples to the deck, will perform in-situ and remote-sensing investigations to characterize the chemistry of materials at the local surface, subsurface, and atmosphere. Lander instruments will also identify the potential history of key indicator elements of significance to the biological potential of Mars, including potential organics within any accessible water ice. Precise trajectory control and targeting were necessary in order to achieve the accurate atmospheric entry conditions required for arriving at the desired landing site. The challenge for the trajectory control maneuver design was to meet or exceed these requirements in the presence of spacecraft limitations as well as other mission constraints. This paper describes the strategies used, including the specialized targeting specifically developed for PHX, in order to design and successfully execute the propulsive maneuvers that delivered the spacecraft to its targeted landing site while satisfying the planetary protection requirements in the presence of flight system constraints.

  15. Orbital maneuvering vehicle teleoperation and video data compression

    NASA Technical Reports Server (NTRS)

    Jones, Steve

    1989-01-01

    The Orbital Maneuvering Vehicle (OMV) and concepts of teleoperation and video data compression as applied to OMV design and operation are described. The OMV provides spacecraft delivery, retrieval, reboost, deboost and viewing services, with ground-control or Space Station operation, through autonomous navigation and pilot controlled maneuvers. Communications systems are comprised of S-band RF command, telemetry, and compressed video data links through the TDRSS and GSTDN networks. The control console video monitors display a monochrome image at an update rate of five frames per second. Depending upon the mode of operation selected by the pilot, the video resolution is either 255 x 244 pixels, or 510 x 244 pixels. Since practically all video image redundancy is removed by the compression process, the video reconstruction is particularly sensitive to data transmission bit errors. Concatenated Reed-Solomon and convolution coding are used with helical data interleaving for error detection and correction, and an error-containment process minimizes the propagation of error effects throughout the video image. Video sub-frame replacement is used, in the case of a non-correctable error or error burst, to minimize the visual impact to the pilot.

  16. Independent Orbiter Assessment (IOA): Analysis of the manned maneuvering unit

    NASA Technical Reports Server (NTRS)

    Bailey, P. S.

    1986-01-01

    Results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items (PCIs). To preserve indepedence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Manned Maneuvering Unit (MMU) hardware. The MMU is a propulsive backpack, operated through separate hand controllers that input the pilot's translational and rotational maneuvering commands to the control electronics and then to the thrusters. The IOA analysis process utilized available MMU hardware drawings and schematics for defining hardware subsystems, assemblies, components, and hardware items. Final levels of detail were evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the worst case severity of the effect for each identified failure mode. The IOA analysis of the MMU found that the majority of the PCIs identified are resultant from the loss of either the propulsion or control functions, or are resultant from inability to perform an immediate or future mission. The five most severe criticalities identified are all resultant from failures imposed on the MMU hand controllers which have no redundancy within the MMU.

  17. Synthetic C-start maneuver in fish-like swimming

    NASA Astrophysics Data System (ADS)

    Zenit, R.; Godoy-Diana, R.

    2013-11-01

    We investigate the mechanics of the unsteady fish-like swimming maneuver using a simplified experimental model in a water tank. A flexible foil (which emulates the fish body) is impulsively actuated by rotating a cylindrical rod that holds the foil. This rod constitutes the head of the swimmer and is mounted through the shaft of the driving motor on an rail with an air bearing. The foil is initially positioned at a start angle and then rapidly rotated to a final angle, which coincides with the free-moving direction of the rail. As the foil rotates, it pushes the surrounding fluid, it deforms and stores elastic energy which drive the recovery of the straight body shape after the motor actuation has stopped; during the rotation, a trust force is induced which accelerates the array. We measure the resulting escape velocity and acceleration as a function of the beam stiffness, size, initial angle, etc. Some measurements of the velocity field during the escape were obtained using a PIV technique. The measurements agree well with a simple mechanical model that quantifies the impulse of the maneuver. The objective of this work is to understand the fundamental mechanisms of thrust generation in unsteady fast-start swimming. We acknowledge support of EADS Foundation through the project ``Fluids and elasticity in biomimetic propulsion'' and of the Chaire Total for RZ as a visiting professor at ESPCI ParisTech.

  18. Learning evasive maneuvers using evolutionary algorithms and neural networks

    NASA Astrophysics Data System (ADS)

    Kang, Moung Hung

    In this research, evolutionary algorithms and recurrent neural networks are combined to evolve control knowledge to help pilots avoid being struck by a missile, based on a two-dimensional air combat simulation model. The recurrent neural network is used for representing the pilot's control knowledge and evolutionary algorithms (i.e., Genetic Algorithms, Evolution Strategies, and Evolutionary Programming) are used for optimizing the weights and/or topology of the recurrent neural network. The simulation model of the two-dimensional evasive maneuver problem evolved is used for evaluating the performance of the recurrent neural network. Five typical air combat conditions were selected to evaluate the performance of the recurrent neural networks evolved by the evolutionary algorithms. Analysis of Variance (ANOVA) tests and response graphs were used to analyze the results. Overall, there was little difference in the performance of the three evolutionary algorithms used to evolve the control knowledge. However, the number of generations of each algorithm required to obtain the best performance was significantly different. ES converges the fastest, followed by EP and then by GA. The recurrent neural networks evolved by the evolutionary algorithms provided better performance than the traditional recommendations for evasive maneuvers, maximum gravitational turn, for each air combat condition. Furthermore, the recommended actions of the recurrent neural networks are reasonable and can be used for pilot training.

  19. AhNRAMP1 iron transporter is involved in iron acquisition in peanut.

    PubMed

    Xiong, Hongchun; Kobayashi, Takanori; Kakei, Yusuke; Senoura, Takeshi; Nakazono, Mikio; Takahashi, Hirokazu; Nakanishi, Hiromi; Shen, Hongyun; Duan, Penggen; Guo, Xiaotong; Nishizawa, Naoko K; Zuo, Yuanmei

    2012-07-01

    Peanut/maize intercropping is a sustainable and effective agroecosystem to alleviate iron-deficiency chlorosis. Using suppression subtractive hybridization from the roots of intercropped and monocropped peanut which show different iron nutrition levels, a peanut gene, AhNRAMP1, which belongs to divalent metal transporters of the natural resistance-associated macrophage protein (NRAMP) gene family was isolated. Yeast complementation assays suggested that AhNRAMP1 encodes a functional iron transporter. Moreover, the mRNA level of AhNRAMP1 was obviously induced by iron deficiency in both roots and leaves. Transient expression, laser microdissection, and in situ hybridization analyses revealed that AhNRAMP1 was mainly localized on the plasma membrane of the epidermis of peanut roots. Induced expression of AhNRAMP1 in tobacco conferred enhanced tolerance to iron deprivation. These results suggest that the AhNRAMP1 is possibly involved in iron acquisition in peanut plants. PMID:22611231

  20. AH-64 IHADSS aviator vision experiences in Operation Iraqi Freedom

    NASA Astrophysics Data System (ADS)

    Hiatt, Keith L.; Rash, Clarence E.; Harris, Eric S.; McGilberry, William H.

    2004-09-01

    Forty AH-64 Apache aviators representing a total of 8564 flight hours and 2260 combat hours during Operation Iraqi Freedom and its aftermath were surveyed for their visual experiences with the AH-64's monocular Integrated Helmet and Display Sighting System (IHADSS) helmet-mounted display in a combat environment. A major objective of this study was to determine if the frequencies of reports of visual complaints and illusions reported in the previous studies, addressing mostly benign training environments, differ in the more stressful combat environments. The most frequently reported visual complaints, both while and after flying, were visual discomfort and headache, which is consistent with previous studies. Frequencies of complaints after flying in the current study were numerically lower for all complaint types, but differences from previous studies are statistically significant only for visual discomfort and disorientation (vertigo). With the exception of "brownout/whiteout," reports of degraded visual cues in the current study were numerically lower for all types, but statistically significant only for impaired depth perception, decreased field of view, and inadvertent instrumental meteorological conditions. This study also found statistically lower reports of all static and dynamic illusions (with one exception, disorientation). This important finding is attributed to the generally flat and featureless geography present in a large portion of the Iraqi theater and to the shift in the way that the aviators use the two disparate visual inputs presented by the IHADSS monocular design (i.e., greater use of both eyes as opposed to concentrating primarily on display imagery).

  1. Aeroelastic characteristics of the AH-64 bearingless tail rotor

    NASA Technical Reports Server (NTRS)

    Banerjee, D.

    1988-01-01

    The results of a wind tunnel test program to determine the performance loads and dynamic characteristics of the Composite Flexbeam Tail Rotor (CFTR) for the AH-64 Advanced Attack Helicopter are reported. The CFTR uses an elastomeric shear attachment of the flexbeam to the hub to provide soft-inplane S-mode and stiff-inplane C-mode configuration. The properties of the elastomer were selected for proper frequency placement and scale damping of the inplane S-mode. Kinematic pitch-lag coupling was introduced to provide the first cyclic inplane C-mode damping at high collective pitch. The CFTR was tested in a wind tunnel over the full slideslip envelop of the AH-64. It is found that the rotor was aeroelastically stable throughout the complete collective pitch range and up to rotor speeds of 1403 rpm. The dynamic characteristics of the rotor were found to be satisfactory at all pitch angles and rotor speeds of the tunnel tests. The design characteristics of the rotor which permit the high performance characteristics are discussed. Several schematic drawings and photographs of the rotor are provided.

  2. Characterization of naturally acquired multiple-drug resistance of Yoshida rat ascites hepatoma AH66 cell line.

    PubMed

    Miyamoto, K; Wakabayashi, D; Minamino, T; Nomura, M; Wakusawa, S; Nakamura, S

    1996-01-01

    Characteristics of multiple-drug resistance of rat ascites hepatoma AH66, a cell line induced by dimethylaminoazobenzene and established as a transplantable tumor, were compared with those of AH66F, a drug sensitive line obtained from AH66. The AH66 cell line was resistant to vinblastine, adriamycin, SN-38 an active form of camptothesine, etoposide, and clorambucil by 10-fold or more than the AH66F cell line. The resistance of AH66 cells to vinblastine, adriamycin, and SN-38 was closely related to P-glycoprotein overexpression in the plasma membrane, because the resistance was significantly inhibited by verapamil. AH66 cells contained much glutahione and had a high activity of glutathione S-transferase P-form (GST-P), compared with AH66F cells, and resistance to clorambucil was decreased by treatment with buthionine sulfoximine, an inhibitor of glutathione synthesis. AH66 cells have a similar topoisomerase I activity, but about 6 times lower topoisomerase II activity than AH66F cells. Therefore, the resistance to etoposide and a part of the resistance to adriamycin of AH66 cells seems to depend upon this low topoisomerase II activity. These results, show that the AH66 cell line has high multiple-drug resistance compared with the AH66F cell line, by several mechanisms. Consequently, the AH66 and AH66F cell lines are useful to study naturally acquired multiple-drug resistance of hepatomas. PMID:8702243

  3. 77 FR 2680 - Defense Federal Acquisition Regulation Supplement; Definition of Cost or Pricing Data

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-19

    ... definition of cost or pricing data, published at 75 FR 53135 on August 30, 2010. II. Executive Orders 12866... cost or pricing data, published at 75 FR 53135 on August 30, 2010. DoD does not expect this proposed... RIN 0750-AH49 Defense Federal Acquisition Regulation Supplement; Definition of Cost or Pricing...

  4. Detecting Spread of Avian Influenza A(H7N9) Virus Beyond China

    PubMed Central

    Havers, Fiona; Iuliano, A. Danielle; Davis, C. Todd; Sar, Borann; Sovann, Ly; Chin, Savuth; Corwin, Andrew L.; Vongphrachanh, Phengta; Douangngeun, Bounlom; Lindblade, Kim A.; Chittaganpitch, Malinee; Kaewthong, Viriya; Kile, James C.; Nguyen, Hien T.; Pham, Dong V.; Donis, Ruben O.; Widdowson, Marc-Alain

    2015-01-01

    During February 2013–March 2015, a total of 602 human cases of low pathogenic avian influenza A(H7N9) were reported; no autochthonous cases were reported outside mainland China. In contrast, since highly pathogenic avian influenza A(H5N1) reemerged during 2003 in China, 784 human cases in 16 countries and poultry outbreaks in 53 countries have been reported. Whether the absence of reported A(H7N9) outside mainland China represents lack of spread or lack of detection remains unclear. We compared epidemiologic and virologic features of A(H5N1) and A(H7N9) and used human and animal influenza surveillance data collected during April 2013–May 2014 from 4 Southeast Asia countries to assess the likelihood that A(H7N9) would have gone undetected during 2014. Surveillance in Vietnam and Cambodia detected human A(H5N1) cases; no A(H7N9) cases were detected in humans or poultry in Southeast Asia. Although we cannot rule out the possible spread of A(H7N9), substantial spread causing severe disease in humans is unlikely. PMID:25897654

  5. Deciphering Dimerization Modes of PAS Domains: Computational and Experimental Analyses of the AhR:ARNT Complex Reveal New Insights Into the Mechanisms of AhR Transformation

    PubMed Central

    Corrada, Dario; Soshilov, Anatoly A.; Denison, Michael S.

    2016-01-01

    The Aryl hydrocarbon Receptor (AhR) is a transcription factor that mediates the biochemical response to xenobiotics and the toxic effects of a number of environmental contaminants, including dioxins. Recently, endogenous regulatory roles for the AhR in normal physiology and development have also been reported, thus extending the interest in understanding its molecular mechanisms of activation. Since dimerization with the AhR Nuclear Translocator (ARNT) protein, occurring through the Helix-Loop-Helix (HLH) and PER-ARNT-SIM (PAS) domains, is needed to convert the AhR into its transcriptionally active form, deciphering the AhR:ARNT dimerization mode would provide insights into the mechanisms of AhR transformation. Here we present homology models of the murine AhR:ARNT PAS domain dimer developed using recently available X-ray structures of other bHLH-PAS protein dimers. Due to the different reciprocal orientation and interaction surfaces in the different template dimers, two alternative models were developed for both the PAS-A and PAS-B dimers and they were characterized by combining a number of computational evaluations. Both well-established hot spot prediction methods and new approaches to analyze individual residue and residue-pairwise contributions to the MM-GBSA binding free energies were adopted to predict residues critical for dimer stabilization. On this basis, a mutagenesis strategy for both the murine AhR and ARNT proteins was designed and ligand-dependent DNA binding ability of the AhR:ARNT heterodimer mutants was evaluated. While functional analysis disfavored the HIF2α:ARNT heterodimer-based PAS-B model, most mutants derived from the CLOCK:BMAL1-based AhR:ARNT dimer models of both the PAS-A and the PAS-B dramatically decreased the levels of DNA binding, suggesting this latter model as the most suitable for describing AhR:ARNT dimerization. These novel results open new research directions focused at elucidating basic molecular mechanisms underlying the

  6. Near Earth Asteroid redirect missions based on gravity assist maneuver

    NASA Astrophysics Data System (ADS)

    Ledkov, Anton; Shustov, Boris M.; Eismont, Natan; Boyarsky, Michael; Nazirov, Ravil; Fedyaev, Konstantin

    During last years several events attracted world community attention to the hazards of hitting the Earth by sky objects. One of these objects is Apophis asteroid what was expected with nonzero probability to hit the Earth in 2036. Luckily after more precise measurements this event is considered as practically improbable. But the other object has really reached the Earth, entered the atmosphere in the Chelyabinsk area and caused vast damages. After this the hazardous near Earth objects problem received practical confirmation of the necessity to find the methods of its resolution. The methods to prevent collision of the dangerous sky object with the Earth proposed up to now look not practical enough if one mentions such as gravitational tractor or changing the reflectivity of the asteroid surface. Even the method supposing the targeting of the spacecraft to the hazardous object in order to deflect it from initial trajectory by impact does not work because its low mass as compared with the mass of asteroid to be deflected. For example the mass of the Apophis is estimated to be about 40 million tons but the spacecraft which can be launched to intercept the asteroid using contemporary launchers has the mass not more than 5 tons. So the question arises where to find the heavier projectile which is possible to direct to the dangerous object? The answer proposed in our paper is very simple: to search it among small near Earth asteroids. As small ones we suppose those which have the cross section size not more than 12-15 meters and mass not exceeding 1500 -1700 tons. According to contemporary estimates the number of such asteroids is not less than 100000. The other question is how to redirect such asteroid to the dangerous one. In the paper the possibilities are studied to use for that purpose gravity assist maneuvers near Earth. It is shown that even among asteroids included in contemporary catalogue there are the ones which could be directed to the trajectory of the

  7. Modeling helicopter near-horizon harmonic noise due to transient maneuvers

    NASA Astrophysics Data System (ADS)

    Sickenberger, Richard D.

    A new first principles model has been developed to estimate the external harmonic noise radiation for a helicopter performing transient maneuvers in the longitudinal plane. This model, which simulates the longitudinal fuselage dynamics, main rotor blade flapping, and far field acoustics, was validated using in-flight measurements and recordings from ground microphones during a full-scale flight test featuring a Bell 206B-3 helicopter. The flight test was specifically designed to study transient maneuvers. The validated model demonstrated that the flapping of the main rotor blades does not significantly affect the acoustics radiated by the helicopter during maneuvering flight. Furthermore, the model also demonstrated that Quasi-Static Acoustic Mapping (Q-SAM) methods can be used to reliably predict the noise radiated during transient maneuvers. The model was also used to identify and quantify the contributions of main rotor thickness noise, low frequency loading noise, and blade-vortex interaction (BVI) noise during maneuvering flight for the Bell 206B-3 helicopter. Pull-up and push-over maneuvers from pure longitudinal cyclic and pure collective control inputs were investigated. The contribution of thickness noise and low frequency loading noise during maneuvering flight was found to depend on the orientation of the tip-path plane relative to the observer. The contribution of impulsive BVI noise during maneuvering flight was found to depend on the inflow through the main rotor and the orientation of the tip-path plane relative to the observer.

  8. Teaching Cardiac Autonomic Function Dynamics Employing the Valsalva (Valsalva-Weber) Maneuver

    ERIC Educational Resources Information Center

    Junqueira, Luiz Fernando, Jr.

    2008-01-01

    In this report, a brief history of the Valsalva (Valsalva-Weber) maneuver is outlined, followed by an explanation on the use of this approach for the evaluation of cardiac autonomic function based on underlying heart rate changes. The most important methodological and interpretative aspects of the Valsalva-Weber maneuver are critically updated,…

  9. 32 CFR Appendix C to Part 552 - Authorized Activities for Fort Lewis Maneuver Area Access

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 3 2011-07-01 2009-07-01 true Authorized Activities for Fort Lewis Maneuver Area Access C Appendix C to Part 552 National Defense Department of Defense (Continued) DEPARTMENT OF.... 552, App. C Appendix C to Part 552—Authorized Activities for Fort Lewis Maneuver Area Access...

  10. Qigong and L-1 straining maneuver oxygen system requirements with and without positive pressure breathing.

    PubMed

    Zhang, S X; Guo, H Z; Zhu, J; Jing, B S

    1994-11-01

    Based on the characteristics of respiration and the intrathoracic pressure in Qigong (Q-G) maneuvering, it has been theorized that the Q-G maneuver may lessen the lack of coordination between aircraft oxygen apparatus and anti-G maneuvers and may be more compatible with positive pressure breathing (PPB). In an experiment intended to test this hypothesis, 5 male volunteers, trained in Q-G and L-1 maneuvers, performed the Q-G and the L-1 maneuvers without and with (PPB) at 4 and 6 kPa, respectively, with 14 respiratory parameters being measured. The results demonstrated that, when performing Q-G maneuver, the maximal expiratory flow rate averaged 1.175-1.645 L.s-1, the inspiratory peak flow, 1.003-1.297 L.s-1. Both these values were markedly lower than those of the L-1 maneuver, and matched well the performance of current aircraft oxygen apparatus. From the blood pressure and heart rate values, it is evident that PPB can further promote the blood pressure-raising effect of the Q-G maneuver, and alleviate pilots' fatigue. PMID:7840751

  11. 33 CFR 83.34 - Maneuvering and warning signals (Rule 34).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Maneuvering and warning signals (Rule 34). 83.34 Section 83.34 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INLAND NAVIGATION RULES RULES Sound and Light Signals § 83.34 Maneuvering and warning signals (Rule 34). (a) Whistle signals. When...

  12. Avoiding a maneuvering aircraft with TCAS. [Traffic Alert and Collison Avoidance System

    NASA Technical Reports Server (NTRS)

    Chappell, Sheryl L.

    1989-01-01

    The present investigation was carried out in NASA's Man-Vehicle Systems Research Facility B 727 simulator because of the need for veridical aircraft response. Pilot performance was measured in testing TCAS II after an avoidance maneuver has been initiated. A proposed change to the system will cause the TCAS II to issue a subsequent maneuver. This maneuver may be an increase in climb or descent rate from 1500 to 2500 ft/min, or a change from a climb to a descent or a descent to a climb. Three questions were addressed: (1) can the pilot detect the change in the maneuver advisory, (2) can the pilot respond promptly and accurately to the new advisory, and (3) can the maneuver be performed in the normal operating envelope of the aircraft. The reaction times found in the study suggest that pilots are able to respond within the two seconds targeted by the TCAS logic. The pilot performance data were used to modify the TCAS II logic to reflect actual pilot performance. This will result in a safe and appropriate maneuver selection in the rare instance when the conflicting aircraft maneuvers, and by doing so invalidates the initial maneuver issued by the collision avoidance system.

  13. The application of integral performance criteria to the analysis of discrete maneuvers in a driving simulator

    NASA Technical Reports Server (NTRS)

    Repa, B. S.; Zucker, R. S.; Wierwille, W. W.

    1977-01-01

    The influence of vehicle transient response characteristics on driver-vehicle performance in discrete maneuvers as measured by integral performance criteria was investigated. A group of eight ordinary drivers was presented with a series of eight vehicle transfer function configurations in a driving simulator. Performance in two discrete maneuvers was analyzed by means of integral performance criteria. Results are presented.

  14. Applying Dynamical Systems Theory to Optimize Libration Point Orbit Stationkeeping Maneuvers for WIND

    NASA Technical Reports Server (NTRS)

    Brown, Jonathan M.; Petersen, Jeremy D.

    2014-01-01

    NASA's WIND mission has been operating in a large amplitude Lissajous orbit in the vicinity of the interior libration point of the Sun-Earth/Moon system since 2004. Regular stationkeeping maneuvers are required to maintain the orbit due to the instability around the collinear libration points. Historically these stationkeeping maneuvers have been performed by applying an incremental change in velocity, or (delta)v along the spacecraft-Sun vector as projected into the ecliptic plane. Previous studies have shown that the magnitude of libration point stationkeeping maneuvers can be minimized by applying the (delta)v in the direction of the local stable manifold found using dynamical systems theory. This paper presents the analysis of this new maneuver strategy which shows that the magnitude of stationkeeping maneuvers can be decreased by 5 to 25 percent, depending on the location in the orbit where the maneuver is performed. The implementation of the optimized maneuver method into operations is discussed and results are presented for the first two optimized stationkeeping maneuvers executed by WIND.

  15. The Generation of Cues Based on a Maneuver Analysis. Technical Report.

    ERIC Educational Resources Information Center

    Gerlach, Vernon; And Others

    A model for the systematic generation of verbal instructional cues is presented. The model utilizes a task analytic procedure referred to as "Maneuver Analysis," which is outlined and applied to the maneuver Vertical S-A. The cues generated on this basis are compared to current operational cues as found in "How to Fly" manuals, such as ATCM 5k-4…

  16. Detail view of the "underside" of the Orbiter Maneuvering/Reaction Control ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of the "underside" of the Orbiter Maneuvering/Reaction Control Systems pod looking at the two spherical propellant tanks for the Reaction Control System, and the elongated propellant tanks for the Orbiter Maneuvering System. This view was taken at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  17. Closeup of STS-26 Discovery, OV-103, orbital maneuvering system (OMS) leak

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Closeup of STS-26 Discovery, Orbiter Vehicle (OV) 103, orbital maneuvering system (OMS) reaction control system (RCS) nitrogen tetroxide gas leak was captured by a Cobra borescope and displayed on a video monitor. The borescope has a miniature videocamera at the end of a flexible rubber tube and is able to be maneuvered into other inaccessible locations.

  18. Orbital Maneuvering System Design and Performance for the Magnetosperic Multiscale Formation

    NASA Technical Reports Server (NTRS)

    Queen, Steven; Chai, Dean; Placanica, Sam

    2015-01-01

    Once in science mission orbits, the four 0.12-km diameter observatories plan to form a tetrahedron with as little as 4-km of separation between spacecraft. The stated operational goal of maneuvering the fleet is no more often than once every two weeks (on average). Derived maneuvering accuracy requirement levied on the ACS

  19. The Total In-Flight Simulator (TIFS) aerodynamics and systems: Description and analysis. [maneuver control and gust alleviators

    NASA Technical Reports Server (NTRS)

    Andrisani, D., II; Daughaday, H.; Dittenhauser, J.; Rynaski, E.

    1978-01-01

    The aerodynamics, control system, instrumentation complement and recording system of the USAF Total In/Flight Simulator (TIFS) airplane are described. A control system that would allow the ailerons to be operated collectively, as well as, differentially to entrance the ability of the vehicle to perform the dual function of maneuver load control and gust alleviation is emphasized. Mathematical prediction of the rigid body and the flexible equations of longitudinal motion using the level 2.01 FLEXSTAB program are included along with a definition of the vehicle geometry, the mass and stiffness distribution, the calculated mode frequencies and mode shapes, and the resulting aerodynamic equations of motion of the flexible vehicle. A complete description of the control and instrumentation system of the aircraft is presented, including analysis, ground test and flight data comparisons of the performance and bandwidth of the aerodynamic surface servos. Proposed modification for improved performance of the servos are also presented.

  20. Helicopter rotor dynamic inflow modeling for maneuvering flight

    NASA Astrophysics Data System (ADS)

    Krothapalli, Krishnamohan Rao

    Finite-state dynamic inflow models for the wake of a helicopter rotor are necessary for the implementation of real-time flight simulation models. There has been a discrepancy between helicopter simulation model response and true vehicle response that has perplexed researchers for many years. This "off-axis problem" is believed to be caused by inaccurate representation of the inflow at the rotor disk during pitching or rolling maneuvers. Current simulation models predict an initial off-axis response to cyclic stick inputs that are opposite in sign to responses of the corresponding flight tests. This study addresses this problem by modifying existing inflow models to account for variations in the rotor wake during maneuvering flight. It is shown that only compact modifications to finite-state inflow models are needed to capture these effects in the inflow dynamics. Vortex and momentum theories are used to model the effect of wake curvature expected in maneuvering flight. It is believed that the curvature of the wake results in inflow gradients that affect the flapping dynamics, mainly in the off-axis channel. While this effect is greatest in hover, where the inflow is largest, it is also significant for low speed conditions where the inflow is still plays a major role. The curvature and contraction of the wake vary greatly in the flight envelope, so it is necessary to construct a unified model (for the inflow coupling due to wake curvature) that is applicable in all flight conditions. The final result is a modified, Peters-He generalized dynamic wake model with curvature augmentation. Specifically, the L-matrix of the Peters-He model is modified by extending a general vortex tube result for arbitrary load distributions. This extended wake model is then coupled with a rotor flapping model, and the flap and hub moment responses are studied in hover and forward flight. Comparisons are made between the simulation model and the Sikorsky Bearingless Main Rotor (SBMR) at 40

  1. Wild2 approach maneuver strategy used for Stardust spacecraft (extended abstract)

    NASA Technical Reports Server (NTRS)

    Bhar, Ramachandra S.; Williams, Kenneth E.; Helfrich, Clifford E.; Kennedy, Brian M.; Carranza, Eric

    2004-01-01

    Stardust, NASA's first dedicated sample return mission to a comet, successfully flew through the comet dust around Wold2 on January 2, 2004. The spacecraft flew within 236 km of the comet, meeting the mission requirement of 250+/- 50 km on flyby distance. Stardust collected dust particles and took several images of the comet while flying close to Wild2. The spacecraft will return to earth with the comet samples on January 15, 2006. To accomplish the above objective, a large Deep Space Maneuver (DSM#) was implemented during June 17 and 18, 2003 and a series of Trajectory Correction Maneuvers (TCMs) were also implemented during the 30 days prior to encounter. Both maneuver design and executions were influenced by number of factors including the small body ephemeris uncertainty, predictability of small forces arising from 3-axis attitude limit cycling and spacecraft slews. Maneuver design processes, including contingency plans, and maneuver performance characteristics, are discussed in this paper.

  2. Intraoperative protective mechanical ventilation for prevention of postoperative pulmonary complications: a comprehensive review of the role of tidal volume, positive end-expiratory pressure, and lung recruitment maneuvers.

    PubMed

    Güldner, Andreas; Kiss, Thomas; Serpa Neto, Ary; Hemmes, Sabrine N T; Canet, Jaume; Spieth, Peter M; Rocco, Patricia R M; Schultz, Marcus J; Pelosi, Paolo; Gama de Abreu, Marcelo

    2015-09-01

    Postoperative pulmonary complications are associated with increased morbidity, length of hospital stay, and mortality after major surgery. Intraoperative lung-protective mechanical ventilation has the potential to reduce the incidence of postoperative pulmonary complications. This review discusses the relevant literature on definition and methods to predict the occurrence of postoperative pulmonary complication, the pathophysiology of ventilator-induced lung injury with emphasis on the noninjured lung, and protective ventilation strategies, including the respective roles of tidal volumes, positive end-expiratory pressure, and recruitment maneuvers. The authors propose an algorithm for protective intraoperative mechanical ventilation based on evidence from recent randomized controlled trials. PMID:26120769

  3. The aryl hydrocarbon receptor (AhR) mediates resistance to apoptosis induced in breast cancer cells.

    PubMed

    Bekki, Kanae; Vogel, Helena; Li, Wen; Ito, Tomohiro; Sweeney, Colleen; Haarmann-Stemmann, Thomas; Matsumura, Fumio; Vogel, Christoph F A

    2015-05-01

    The aryl hydrocarbon receptor (AhR) is well known as a ligand binding transcription factor regulating various biological effects. Previously we have shown that long-term exposure to estrogen in breast cancer cells caused not only down regulation of estrogen receptor (ER) but also overexpression of AhR. The AhR interacts with several cell signaling pathways associated with induction of tyrosine kinases, cytokines and growth factors which may support the survival roles of AhR escaping from apoptosis elicited by a variety of apoptosis inducing agents in breast cancer. In this study, we studied the anti-apoptotic role of AhR in different breast cancer cells when apoptosis was induced by exposure to UV light and chemotherapeutic agents. Activation of AhR by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in AhR overexpressing breast cancer cells effectively suppressed the apoptotic response induced by UV-irradiation, doxorubicin, lapatinib and paclitaxel. The anti-apoptotic response of TCDD was uniformly antagonized by the treatment with 3'methoxy-4'nitroflavone (MNF), a specific antagonist of AhR. TCDD's survival action of apoptosis was accompanied with the induction of well-known inflammatory genes, such as cyclooxygenase-2 (COX-2) and NF-κB subunit RelB. Moreover, TCDD increased the activity of the immunosuppressive enzyme indoleamine 2, 3-dioxygenase (IDO), which metabolizes tryptophan to kynurenine (Kyn) and mediates tumor immunity. Kyn also acts as an AhR ligand like TCDD, and kyn induced an anti-apoptotic response in breast cancer cells. Accordingly, our present study suggests that AhR plays a pivotal role in the development of breast cancer via the suppression of apoptosis, and provides an idea that the use of AhR antagonists with chemotherapeutic agents may effectively synergize the elimination of breast cancer cells. PMID:25987214

  4. Orbital Maneuvering Vehicle (OMV) plume and plume effects study

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon D.

    1991-01-01

    The objective was to characterize the Orbital Maneuvering Vehicle (OMV) propulsion and attitude control system engine exhaust plumes and predict the resultant plume impingement pressure, heat loads, forces, and moments. Detailed description is provided of the OMV gaseous nitrogen (GN2) thruster exhaust plume flow field characteristics calculated with the RAMP2 snd SFPGEN computer codes. Brief descriptions are included of the two models, GN2 thruster characteristics and RAMP2 input data files. The RAMP2 flow field could be recalculated by other organizations using the information presented. The GN2 flow field can be readily used by other organizations who are interested in GN2 plume induced environments which require local flow field properties which can be supplied using the SFPGEN GN2 model.

  5. Platelet injectors for Space Shuttle orbit maneuvering engine

    NASA Technical Reports Server (NTRS)

    Kahl, R. C.; Labotz, R. J.; Bassham, L. B.

    1974-01-01

    The Space Shuttle Orbit Maneuvering Subsystem Rocket Engine employs a platelet element injector concept. This injector has demonstrated 316-sec vacuum specific impulse performance under simulated altitude conditions when tested with a milled slot/electroformed nickel close-out regenerative chamber and a full 71 area ratio nozzle. To date, over 300 altitude engine tests and 300 stability bomb tests have demonstrated stable, erosion free operation with this concept to test durations of 150 seconds. The injector and chamber also meet the reusable requirements of the shuttle with a cycle life capability in excess of 1000 cycles. An extensive altitude restart program has also demonstrated OMS-engine operation over large variations in the burn and coast times with helium saturated propellants.

  6. Space shuttle orbital maneuvering engine platelet injector program

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A platelet-face injector for the fully reusable orbit maneuvering system OMS on the space shuttle was evaluated as a means of obtaining additional design margin and low cost. Performance, heat transfer, and combustion stability were evaluated over the anticipated range of OMS operating conditions. The effects of acoustic cavity configuration on combustion stability, including cavity depth, open area, inlet contour, and other parameters, were investigated using sea level bomb tests. Prototype injector and chamber behavior was evaluated for a variety of conditions; these tests examined the effects of film cooling, helium saturated propellants, chamber length, inlet conditions, and operating point, on performance, heat transfer and engine transient behavior. Helium bubble ingestion into both propellant circuits was investigated, as was chugging at low pressure operation, and hot and cold engine restart with and without a purge.

  7. Target pitch angle for the microburst escape maneuver

    NASA Technical Reports Server (NTRS)

    Mulgund, Sandeep S.

    1991-01-01

    The objective of this study was to investigate the constant pitch attitude strategy as a possible non-precision maneuver for recovery from inadvertent wind shear encounters. The Wind Shear Training Aid published by the FAA recommends that upon encountering a severe wind shear, the pilot should apply maximum thrust and rotate the aircraft to an initial pitch target angle of 15 degrees. The 15 degrees target was identified through rigorous analyses using six-degree-of-freedom flight simulators and microburst models representative of actual accident cases. It was found that 15 degrees was an effective target for a wide range of shears, and was generally applicable to most jet transports. This work was undertaken to examine the issue of recovery performance in wind shear of other classes of aircraft - notably turboprop commuters and propeller-driven general aviation planes. It should be possible to postulate a target pitch angle (TPA) for such aircraft, as well.

  8. An overview of NASA's role in maneuvering missile aerodynamic technology

    NASA Technical Reports Server (NTRS)

    Sawyer, W. C.; Jackson, C. M., Jr.

    1982-01-01

    This paper presents an overview of the role NASA has had and continues to pursue in providing missile aerodynamic technology. In the past, NASA has provided considerable support to the missile industry and the military. The support has generally taken the form of theoretical aerodynamic analyses, experimental studies to provide solutions for specific problems, and the documentation of existing foreign missile systems and domestic missiles. In 1975, NASA shifted its missile-related efforts in aerodynamics from this largely service role to one of conducting more basic research. The areas of research include: innovative methods for roll control of cruciform missiles, airbreathing missiles with maneuver requirements, and an advanced generation of monoplanar missiles for efficient supersonic carriage and delivery.

  9. Ultrasonography for the assessment of lung recruitment maneuvers.

    PubMed

    Tusman, Gerardo; Acosta, Cecilia M; Costantini, Mauro

    2016-12-01

    Lung collapse is a known complication that affects most of the patients undergoing positive pressure mechanical ventilation. Such atelectasis and airways closure lead to gas exchange and lung mechanics impairment and has the potential to develop an inflammatory response in the lungs. These negative effects of lung collapse can be reverted by a lung recruitment maneuver (RM) i.e. a ventilatory strategy that resolves lung collapse by a brief and controlled increment in airway pressures. However, an unsolved question is how to assess such RM at the bedside. The aim of this paper is to describe the usefulness of lung sonography (LUS) to conduct and personalize RM in a real-time way at the bedside. LUS has favorable features to assess lung recruitment due to its high specificity and sensitivity to detect lung collapse together with its non-invasiveness, availability and simple use. PMID:27496127

  10. Control and structural optimization for maneuvering large spacecraft

    NASA Technical Reports Server (NTRS)

    Chun, H. M.; Turner, J. D.; Yu, C. C.

    1990-01-01

    Presented here are the results of an advanced control design as well as a discussion of the requirements for automating both the structures and control design efforts for maneuvering a large spacecraft. The advanced control application addresses a general three dimensional slewing problem, and is applied to a large geostationary platform. The platform consists of two flexible antennas attached to the ends of a flexible truss. The control strategy involves an open-loop rigid body control profile which is derived from a nonlinear optimal control problem and provides the main control effort. A perturbation feedback control reduces the response due to the flexibility of the structure. Results are shown which demonstrate the usefulness of the approach. Software issues are considered for developing an integrated structures and control design environment.

  11. Role of Wing/Body Flexibility in Insect Maneuver

    NASA Astrophysics Data System (ADS)

    Li, Chengyu; Dong, Haibo; Zeyghami, Samane; Flow Simulation Research Group(FSRG) Team

    2011-11-01

    It's widely thought insects are able to accomplish fast maneuver via adjustment of wing kinematics. However, it's still unclear how wing flexibility plays roles in this process. In this work, an integrated study combining high-speed photogrammetry and direct numerical simulation (DNS), for a freely flying dragonfly (Erythemis Simplicicollis) in 110 degree turn, is used to reveal both aerodynamic and dynamic roles of its body and wings. Quantitative measurements have shown the significant difference of deformation between all wings as well as up to 18 degree bending of the tail. Unsteady 3D vortex formation and associated aerodynamic forces calculated from high-fidelity simulations are used to illustrate how the turn is accomplished within three dragonfly wing beats. This work is supported by NSF CBET-1055949. NSF CBET-1055949.

  12. Behavior learning in differential games and reorientation maneuvers

    NASA Astrophysics Data System (ADS)

    Satak, Neha

    method is the Direct Approximation of Value Function (DAVF) method. In this method, unlike the CSR method, the player formulates an objective function for the opponent but does not formulates a strategy directly; rather, indirectly the player assumes that the opponent is playing optimally. Thus, a value function satisfying the HJB equation corresponding to the opponent's cost function exists. The DAVF method finds an approximate solution for the value function based on previous observations of the opponent's control. The approximate solution to the value function is then used to predict the opponent's future behavior. Game examples in which only a single player is learning its opponent's behavior are simulated. Subsequently, examples in which both players in a two-player game are learning each other's behavior are simulated. In the second part of this research, a reorientation control maneuver for a spinning spacecraft will be developed. This will aid the application of behavior learning and differential games concepts to the specific scenario involving multiple spinning spacecraft. An impulsive reorientation maneuver with coasting will be analytically designed to reorient the spin axis of the spacecraft using a single body fixed thruster. Cooperative maneuvers of multiple spacecraft optimizing fuel and relative orientation will be designed. Pareto optimality concepts will be used to arrive at mutually agreeable reorientation maneuvers for the cooperating spinning spacecraft.

  13. Meteoroid and orbital debris shielding on the Orbital Maneuvering Vehicle

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, Marc E.

    1989-01-01

    NASA's Orbital Maneuvering Vehicle (OMV) is being designed to withstand a 10-year lifetime in polar and low earth orbits. A large percentage of OMV's lifetime will be spent operating in the vicinity of the Space Shuttle and Space Station or in storage at these manned locations. An extensive analysis has been performed to determine the effects of the meteoroid and orbital debris environments on OMV's external fuel tanks. A finite element model of OMV was constructed using NASTRAN and analyzed with the meteoroid and debris design analysis code BUMPER. The results show that the long design lifetime, and the ever increasing man-made orbital debris environment, will require the use of shielding over the external fuel tanks.

  14. Adaptive beamforming of a towed array during maneuvering

    NASA Astrophysics Data System (ADS)

    Gong, Zaixiao; Lin, Peng; Guo, Yonggang; Zhang, Renhe; Li, Fenghua

    2012-11-01

    During maneuvering, the performance of Minimum Variance Distortion-less Response (MVDR) beamforming for a towed hydrophone array will greatly degrade due to shape error. Under the assumption that the shape of a towed array changes in a known way during the observation interval, an improved MVDR method is proposed. A static array with average shape during the observation interval is taken as a reference array shape. The phase difference of the cross spectral density matrix (CSDM) between the time-varying array and the reference array is compensated on each azimuth. A coherent CSDM accumulation can then be achieved. Experimental results show that the improved MVDR method can yield better performance than conventional MVDR with a time-varying array. This helps to resolve the problems of left-right target ambiguity and weak signal detection for time-varying arrays.

  15. Input shaped control of 3-dimensional maneuvers of flexible spacecraft

    NASA Technical Reports Server (NTRS)

    Singh, T.; Vadali, S. R.

    1992-01-01

    This paper deals with the control of three dimensional rotational maneuvers of flexible spacecraft. A spacecraft with a spherical hub and six symmetric appendages is considered here as a model. The appendages are long and flexible leading to low frequency vibration under any control action. To provide a comprehensive treatment of input shaped controllers, both open loop and closed loop controllers are considered. The minimum-time bang-bang and the near-minimum-time controller, used in conjunction with the shaped input technique are studied. In addition, a combination of a Liapunov controller with the shaped input control technique is proposed to take advantage of the simple feedback control strategy and augment it with a technique that can eliminate the vibratory motion of the flexible appendages more efficiently.

  16. Visual display aid for orbital maneuvering - Experimental evaluation

    NASA Technical Reports Server (NTRS)

    Grunwald, Arthur J.; Ellis, Stephen R.

    1993-01-01

    An interactive proximity operations planning system, which allows on-site planning of fuel-efficient, multiburn maneuvers in a potential multispacecraft environment, has been experimentally evaluated. An experiment has been carried out in which nonastronaut operators with brief initial training were required to plan a trajectory to retrieve an object accidentally separated from a dual-keel Space Station, for a variety of different orbital situations. The experiments have shown that these operators were able to plan workable trajectories, satisfying a number of operational constraints. Fuel use and planning time were strongly correlated, both with the angle at which the object was separated and with the existence of spatial constraints. Planning behavior was found to be strongly operator-dependent. This finding calls for the need for standardizing planning strategies through operator training or the use of semiautomated planning schemes.

  17. Optimal control of aeroassisted plane change maneuver using feedback expansions

    NASA Technical Reports Server (NTRS)

    Mishne, D.; Speyer, J. L.

    1986-01-01

    A guidance law for an aeroassisted plane change maneuver is developed by an asymptotic expansion technique using a small parameter which essentially represents the ratio of the inertial forces to the atmospheric forces. This guidance law minimizes the energy loss while meeting terminal constraints on the altitude, flight path angle, and heading angle. By neglecting the inertial forces, the resulting optimization problem is integrable and can be determined in closed form. This zeroth-order solution is the first term in an asymptotic series solution of the Hamilton-Jacobi-Bellman equation. The remaining terms are determined from the solution of a first-order, linear partial differential equation whose solution requires only quadrature integration. Our initial results in using this guidance scheme are encouraging.

  18. Differential maneuvering simulator data reduction and analysis software

    NASA Technical Reports Server (NTRS)

    Beasley, G. P.; Sigman, R. S.

    1972-01-01

    A multielement data reduction and analysis software package has been developed for use with the Langley differential maneuvering simulator (DMS). This package, which has several independent elements, was developed to support all phases of DMS aircraft simulation studies with a variety of both graphical and tabular information. The overall software package is considered unique because of the number, diversity, and sophistication of the element programs available for use in a single study. The purpose of this paper is to discuss the overall DMS data reduction and analysis package by reviewing the development of the various elements of the software, showing typical results that can be obtained, and discussing how each element can be used.

  19. Noncircular rolling joints for vibrational reduction in slewing maneuvers

    NASA Technical Reports Server (NTRS)

    Chew, Meng-Sang (Inventor); Juang, Jer-Nan (Inventor); Yang, Li-Farn (Inventor)

    1992-01-01

    A rolling joint is provided for obtaining slewing maneuvers for various apparatus including space structures, space vehicles, robotic manipulators, and simulators. Two noncircular cylinders, namely a drive and a driven cylinder, are provided in driving contact with one another. This contact is maintained by two pairs of generally S-shaped bands, each pair forming a generally 8-shaped coupling tightly about the circumferential periphery of the noncircular drive and driven cylinders. A stationarily fixed arm extends between and is rotatably journalled with a drive axle and a spindle axle respectively extending through selected rotational points of the drive cylinder and of the driven cylinder. The noncircular cylinders are profiled to obtain the desired varying gear ratio. The novelty of the present invention resides in using specifically profiled noncircular cylinders to obtain a desired varying gear ratio.

  20. Sequential Probability Ratio Test for Spacecraft Collision Avoidance Maneuver Decisions

    NASA Technical Reports Server (NTRS)

    Carpenter, J. Russell; Markley, F. Landis

    2013-01-01

    A document discusses sequential probability ratio tests that explicitly allow decision-makers to incorporate false alarm and missed detection risks, and are potentially less sensitive to modeling errors than a procedure that relies solely on a probability of collision threshold. Recent work on constrained Kalman filtering has suggested an approach to formulating such a test for collision avoidance maneuver decisions: a filter bank with two norm-inequality-constrained epoch-state extended Kalman filters. One filter models the null hypotheses that the miss distance is inside the combined hard body radius at the predicted time of closest approach, and one filter models the alternative hypothesis. The epoch-state filter developed for this method explicitly accounts for any process noise present in the system. The method appears to work well using a realistic example based on an upcoming, highly elliptical orbit formation flying mission.

  1. Manual control aspects of Space Station docking maneuvers

    NASA Technical Reports Server (NTRS)

    Brody, Adam R.; Ellis, Stephen R.

    1990-01-01

    Due to an increase in spacecraft traffic forecasted for the Space Station era, researchers are investigating manual control and other aspects of docking operations with hopes of increasing safety, productivity, and likelihood of success while decreasing cost. Experiments have been performed which revealed the effect of approach velocity, in-flight anomalies, and control mode. Displays have been designed to enable flight planners to more easily overcome the difficulties presented by orbital mechanics. Improved understanding of human factors in the docking mission and other orbital maneuvers will play a significant role in design tradeoffs concerning thruster size, docking fixture style and mass, and on-board trajectory planning displays. Incorporating both empirical and analytic results into current and future planning of missions occurring not only in earth orbit, but also for missions in lunar and Mars orbit, will expand the performance envelopes of the astronauts who participate in these missions.

  2. Role of the manned maneuvering unit for the Space Station

    NASA Technical Reports Server (NTRS)

    Whitsett, C. E.

    1986-01-01

    The performance specifications to be realized in the Manned Maneuvering Unit (MMU) for Space Station operations will be the culmination of design efforts which began during the Gemini project. The types of MMUs which have been built and tested over the past two decades are described, including handheld, jet shoe, and initial rigid backpack configurations. Efforts to enhance the control laws and human factors aspects of the Skylab MMU to meet long-duration, flexible use Space Station requirements are summarized, noting the successes and deficiencies with the Shuttle MMU. The design requirements which must be met to allow the Space Station MMU to be used to perform rescue, transportation, inspection, assembly, contingency, and programmatic missions are explored.

  3. Noncircular rolling joints for vibrational reduction in slewing maneuvers

    NASA Astrophysics Data System (ADS)

    Chew, Meng-Sang; Juang, Jer-Nan; Yang, Li-Farn

    1992-09-01

    A rolling joint is provided for obtaining slewing maneuvers for various apparatus including space structures, space vehicles, robotic manipulators, and simulators. Two noncircular cylinders, namely a drive and a driven cylinder, are provided in driving contact with one another. This contact is maintained by two pairs of generally S-shaped bands, each pair forming a generally 8-shaped coupling tightly about the circumferential periphery of the noncircular drive and driven cylinders. A stationarily fixed arm extends between and is rotatably journalled with a drive axle and a spindle axle respectively extending through selected rotational points of the drive cylinder and of the driven cylinder. The noncircular cylinders are profiled to obtain the desired varying gear ratio. The novelty of the present invention resides in using specifically profiled noncircular cylinders to obtain a desired varying gear ratio.

  4. Teleoperator Maneuvering System (TMS) mission applications and benefits

    NASA Technical Reports Server (NTRS)

    Cramblit, D. C.; Turner, J. R.

    1984-01-01

    Studies conducted by NASA have shown that the operating range of the Shuttle can be substantially increased and cost of payload operation be decreased by making use of the Teleoperator Maneuvering System (TMS). The TMS is remotely controlled, free-flying, orbital mini-tug vehicle capable of performing a wide range of remote satellite services missions. It can operate out of the Shuttle cargo bay, from a space station, or on top of an upper stage like Centaur. For high energy missions up to and including geostationary orbit, the TMS propulsion stage will augment the Transfer Orbit Stage (TOS) recently proposed for commercial development in providing an effective low-cost second-stage system for delivering intermediate sized payloads to geosynchronous orbit (GEO). Attention is given to TMS capabilities for both long duration and short term orbital missions, taking into account also Space Station support operations.

  5. The NASA/AHS Rotorcraft Noise Reduction Program

    NASA Technical Reports Server (NTRS)

    Childress, Otis S., Jr.

    1988-01-01

    Research of the NASA/AHS noise reduction program is discussed, stressing work in four areas: noise prediction, testing and data base, noise reduction, and criteria development. A program called ROTONET has been developed, using a code structure divided into four main parts; main- and tail-rotor blade geometry, rotor performance, noise calculations, and noise propagation. Wind tunnel tests on individual rotors, and flight tests on a helicopter built specifically to generate a broadband main rotor noise data base have been conducted. In the field of noise reduction, researchers have performed analytical evaluations of low noise rotor concepts, and small-scale wind tunnel evaluations of noise reduction concepts. Under the supervision of the FAA, the program in conducting tests to develop criteria for helicopters and heliports.

  6. Maneuver analysis for spinning thrusting spacecraft and spinning tethered spacecraft

    NASA Astrophysics Data System (ADS)

    Martin, Kaela M.

    During axial thrusting of a spin-stabilized spacecraft undergoing orbital injections or control maneuvers, misalignments and center-of-mass offset create undesired body-fixed torques. The effects of the body-fixed torques, which in turn cause velocity pointing errors, can be reduced by ramping up (and then ramping down) the thruster. The first topic discussed in this thesis derives closed-form solutions for the angular velocity, Euler angles, inertial velocity, and inertial displacement solutions with nonzero initial conditions. Using the closed-form solutions, the effect of variations in the spin-axis moment of inertia and spin-rate on the spacecraft velocity pointing error are shown. The analytical solutions closely match numerical simulations. The next topic considers various ramp-up profiles (including parabolic, cosine, logarithmic, exponential, and cubic) to heuristically find a suboptimal solution to reduce the velocity pointing error. Some of the considered cosine, logarithmic, exponential, parabolic, and cubic profiles drive the velocity pointing error to nearly zero and hence qualify as effective solutions. The third topic examines a large tethered spacecraft that produces artificial gravity with the propulsion system on one end of the tether. Instead of thrusting through the center of mass, the offset thrust occurs at an angle to the tether which is held in the desired direction by changing the spin rate to compensate for decreasing propellant mass. The dynamics and control laws of the system are derived for constant, time-varying, planar, and non-planar thrust as well as spin-up maneuvers. The final topic discusses how the Bodewadt solution of a self-excited rigid body is unable to accurately predict the motion compared to a numerical integration of the equations of motion.

  7. Is there central fatigue during simulated air combat maneuvering?

    PubMed

    Bain, B; Jacobs, I; Buick, F

    1995-01-01

    This study tested the hypothesis that repeated exposure to high levels of +Gz acceleration, in conjunction with repeated execution of an Anti-G Straining Maneuver (AGSM), causes central fatigue, presumably by impairing central nervous system (CNS) function. We speculated that central fatigue would impair the ability to recruit sufficient musculature at the intensity required to perform an adequate anti-G straining maneuver. Central fatigue was evaluated by measuring maximal force generation and surface electromyographic activity of leg extensor muscles before, during, and immediately upon termination of an SACM, and comparing these values to those obtained when the muscles were electrically stimulated during maximal voluntary contractions (MVCs). We assumed that any observed increase in force generation during the MVCs, caused by the stimulation, would indicate central fatigue. G-tolerance time was 230 +/- 172 s. Hypoxia was induced by the SACM as the arterial oxygen saturation decreased significantly from 97% to 90%. In spite of this hypoxia, there was no significant change in MVC force when the pre- and post-SACM values were compared. Electrical stimulation during the MVC's did not cause an increase in force generation. The average forces generated during the +7 Gz phase of the SACM were only about 35% of MVC force. This force value did not change significantly during the SACM. The results indicate that the inability to continue to perform the AGSM during an SACM is not likely due to central fatigue or to fatigue of the large skeletal muscle groups we have examined.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7695543

  8. Estimate of avoidance maneuver rate for HASTOL tether boost facility

    NASA Astrophysics Data System (ADS)

    Forward, Robert L.

    2002-01-01

    The Hypersonic Airplane Space Tether Orbital Launch (HASTOL) Architecture uses a hypersonic airplane (or reusable launch vehicle) to carry a payload from the surface of the Earth to 150 km altitude and a speed of Mach 17. The hypersonic airplane makes a rendezvous with the grapple at the tip of a long, rotating, orbiting space tether boost facility, which picks up the payload from the airplane. Release of the payload at the proper point in the tether rotation boosts the payload into a higher orbit, typically into a Geosynchronous Transfer Orbit (GTO), with lower orbits and Earth escape other options. The HASTOL Tether Boost Facility will have a length of 636 km. Its center of mass will be in a 604 km by 890 km equatorial orbit. It is estimated that by the time of the start of operations of the HASTOL Tether Boost facility in the year 2020, there will be 500 operational spacecraft using the same volume of space as the HASTOL facility. These operational spacecraft would likely be made inoperative by an impact with one of the lines in the multiline HASTOL Hoytether™ and should be avoided. There will also be non-operational spacecraft and large pieces of orbital debris with effective size greater than five meters in diameter that could cut a number of lines in the HASTOL Hoytether™, and should also be avoided. It is estimated, using two different methods and combining them, that the HASTOL facility will need to make avoidance maneuvers about once every four days if the 500 operational spacecraft and large pieces of orbital debris greater than 5 m in diameter, were each protected by a 2 km diameter miss distance protection sphere. If by 2020, the ability to know the positions of operational spacecraft and large pieces of orbital debris improved to allow a 600 m diameter miss distance protection sphere around each object, then the number of HASTOL facility maneuvers needed drops to one every two weeks. .

  9. Propulsion System and Orbit Maneuver Integration in CubeSats: Trajectory Control Strategies Using Micro Ion Propulsion

    NASA Technical Reports Server (NTRS)

    Hudson, Jennifer; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Propulsion System and Orbit Maneuver Integration in CubeSats project aims to solve the challenges of integrating a micro electric propulsion system on a CubeSat in order to perform orbital maneuvers and control attitude. This represents a fundamentally new capability for CubeSats, which typically do not contain propulsion systems and cannot maneuver far beyond their initial orbits.

  10. The tertiary structures of porcine AhR and ARNT proteins and molecular interactions within the TCDD/AhR/ARNT complex.

    PubMed

    Orlowska, Karina; Molcan, Tomasz; Swigonska, Sylwia; Sadowska, Agnieszka; Jablonska, Monika; Nynca, Anna; Jastrzebski, Jan P; Ciereszko, Renata E

    2016-06-01

    The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that can be activated by structurally diverse synthetic and natural chemicals, including toxic environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In the present study, homology models of the porcine AhR-ligand binding domain (LBD) and the porcine aryl hydrocarbon receptor nuclear translocator-ligand binding domain (ARNT-LBD) were created on the basis of structures of closely related respective proteins i.e., human Hif-2α and ARNT. Molecular docking of TCDD to the porcine AhR-LBD model revealed high binding affinity (-8.8kcal/mol) between TCDD and the receptor. Moreover, formation of the TCDD/AhR-LBD complex was confirmed experimentally with the use of electrophoretic mobility shift assay (EMSA). It was found that TCDD (10nM, 2h of incubation) not only bound to the AhR in the porcine granulosa cells but also activated the receptor. The current study provides a framework for examining the key events involved in the ligand-dependent activation of the AhR. PMID:27288759

  11. Annealing helicase 2 (AH2), a DNA-rewinding motor with an HNH motif

    PubMed Central

    Yusufzai, Timur; Kadonaga, James T.

    2010-01-01

    The structure and integrity of DNA is of considerable biological and biomedical importance, and it is therefore critical to identify and to characterize enzymes that alter DNA structure. DNA helicases are ATP-driven motor proteins that unwind DNA. Conversely, HepA-related protein (HARP) protein (also known as SMARCAL1 and DNA-dependent ATPase A) is an annealing helicase that rewinds DNA in an ATP-dependent manner. To date, HARP is the only known annealing helicase. Here we report the identification of a second annealing helicase, which we term AH2, for annealing helicase 2. Like HARP, AH2 catalyzes the ATP-dependent rewinding of replication protein A (RPA)-bound complementary single-stranded DNA, but does not exhibit any detectable helicase activity. Unlike HARP, however, AH2 lacks a conserved RPA-binding domain and does not interact with RPA. In addition, AH2 contains an HNH motif, which is commonly found in bacteria and fungi and is often associated with nuclease activity. AH2 appears to be the only vertebrate protein with an HNH motif. Contrary to expectations, purified AH2 does not exhibit nuclease activity, but it remains possible that AH2 contains a latent nuclease that is activated under specific conditions. These structural and functional differences between AH2 and HARP suggest that different annealing helicases have distinct functions in the cell. PMID:21078962

  12. Equine Influenza A(H3N8) Virus Infection in Cats

    PubMed Central

    Su, Shuo; Wang, Lifang; Fu, Xinliang; He, Shuyi; Hong, Malin; Zhou, Pei; Gray, Gregory

    2014-01-01

    Interspecies transmission of equine influenza A(H3N8) virus has resulted in establishment of a canine influenza virus. To determine if something similar could happen with cats, we experimentally infected 14 cats with the equine influenza A(H3N8) virus. All showed clinical signs, shed virus, and transmitted the virus to a contact cohort. PMID:25417790

  13. Characterization of CYP76AH4 clarifies phenolic diterpenoid biosynthesis in the Lamiaceae

    PubMed Central

    Zi, Jiachen; Peters, Reuben J.

    2013-01-01

    Miltiradiene (1), is the precursor of phenolic diterpenoids such as ferruginol (2), requiring aromatization and hydroxylation. While this has been attributed to a single cytochrome P450 (CYP76AH1), characterization of the rosemary ortholog CYP76AH4 led to the discovery that these CYPs simply hydroxylate the facilely oxidized aromatic intermediate abietatriene (3). PMID:24108414

  14. Use of natural AhR ligands as potential therapeutic modalities against inflammatory disorders.

    PubMed

    Busbee, Philip B; Rouse, Michael; Nagarkatti, Mitzi; Nagarkatti, Prakash S

    2013-06-01

    The aim of this review is to discuss research involving ligands for the aryl hydrocarbon receptor (AhR) and their role in immunomodulation. While activation of the AhR is well known for its ability to regulate the biochemical and toxic effects of environmental chemicals, more recently an exciting discovery has been made indicating that AhR ligation can also regulate T-cell differentiation, specifically through activation of Foxp3(+) regulatory T cells (Tregs) and downregulation of the proinflammatory Th17 cells. Such findings have opened new avenues of research on the possibility of targeting the AhR to treat inflammatory and autoimmune diseases. Specifically, this review will discuss the current research involving natural and dietary AhR ligands. In addition, evidence indicating the potential use of these ligands in regulating inflammation in various diseases will be highlighted. The importance of the AhR in immunological processes can be illustrated by expression of this receptor on a majority of immune cell types. In addition, AhR signaling pathways have been reported to influence a number of genes responsible for mediating inflammation and other immune responses. As interest in the AhR and its ligands increases, it seems prudent to consolidate current research on the contributions of these ligands to immune regulation during the course of inflammatory diseases. PMID:23731446

  15. IMMUNOHISTOCHEMICAL DOUBLE-STAINING FOR AH RECEPTOR AND ARNT IN HUMAN EMBRYONIC PALATAL SHELVES

    EPA Science Inventory

    The aryl hydrocarbon receptor (AhR) and the AhR nuclear translocation protein (ARNT) are helix-loop-helix (HLH) proteins involved in transcriptional regulation. olycyclic aromatic halogenated chemicals, of which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most potent, bind ...

  16. Use of natural AhR ligands as potential therapeutic modalities against inflammatory disorders

    PubMed Central

    Busbee, Philip B; Rouse, Michael; Nagarkatti, Mitzi; Nagarkatti, Prakash S

    2014-01-01

    The aim of this review is to discuss research involving ligands for the aryl hydrocarbon receptor (AhR) and their role in immunomodulation. While activation of the AhR is well known for its ability to regulate the biochemical and toxic effects of environmental chemicals, more recently an exciting discovery has been made indicating that AhR ligation can also regulate T-cell differentiation, specifically through activation of Foxp3+ regulatory T cells (Tregs) and downregulation of the proinflammatory Th17 cells. Such findings have opened new avenues of research on the possibility of targeting the AhR to treat inflammatory and autoimmune diseases. Specifically, this review will discuss the current research involving natural and dietary AhR ligands. In addition, evidence indicating the potential use of these ligands in regulating inflammation in various diseases will be highlighted. The importance of the AhR in immunological processes can be illustrated by expression of this receptor on a majority of immune cell types. In addition, AhR signaling pathways have been reported to influence a number of genes responsible for mediating inflammation and other immune responses. As interest in the AhR and its ligands increases, it seems prudent to consolidate current research on the contributions of these ligands to immune regulation during the course of inflammatory diseases. PMID:23731446

  17. Human Infection with Highly Pathogenic A(H7N7) Avian Influenza Virus, Italy, 2013

    PubMed Central

    Rossini, Giada; Facchini, Marzia; Vaccari, Gabriele; Di Trani, Livia; Di Martino, Angela; Gaibani, Paolo; Vocale, Caterina; Cattoli, Giovanni; Bennett, Michael; McCauley, John W.; Rezza, Giovanni; Moro, Maria Luisa; Rangoni, Roberto; Finarelli, Alba Carola; Landini, Maria Paola; Castrucci, Maria Rita; Donatelli, Isabella

    2014-01-01

    During an influenza A(H7N7) virus outbreak among poultry in Italy during August–September 2013, infection with a highly pathogenic A(H7N7) avian influenza virus was diagnosed for 3 poultry workers with conjunctivitis. Genetic analyses revealed that the viruses from the humans were closely related to those from chickens on affected farms. PMID:25271444

  18. Pityriazepin and other potent AhR ligands isolated from Malassezia furfur yeast.

    PubMed

    Mexia, Nikitia; Gaitanis, Georgios; Velegraki, Aristea; Soshilov, Anatoly; Denison, Michael S; Magiatis, Prokopios

    2015-04-01

    Malassezia furfur yeast strains isolated from diseased human skin preferentially biosynthesize indole alkaloids which can be detected in the human skin and are highly potent activators of the aryl hydrocarbon receptor (AhR) and AhR-dependent gene expression. Chemical analysis of an EtOAc extract of a M. furfur strain obtained from diseased human skin and grown on l-tryptophan agar revealed several known AhR active tryptophan metabolites along with a previously unidentified compound, pityriazepin. While its structure resembled that of the known alkaloid pityriacitrin, the comprised pyridine ring had been transformed into an azepinone. The indoloazepinone scaffold of pityriazepin is extremely rare in nature and has only been reported once previously. Pityriazepin, like the other isolated compounds, was found to be a potent activator of the AhR-dependent reporter gene assay in recombinant cell lines derived from four different species, although significant species differences in relative potency were observed. The ability of pityriazepin to competitively bind to the AhR and directly stimulate AhR DNA binding classified it as a new naturally-occurring potent AhR agonist. M. furfur produces an expanded collection of extremely potent naturally occurring AhR agonists, which produce their biological effects in a species-specific manner. PMID:25721496

  19. Pityriazepin and other potent AhR ligands isolated from Malassezia furfur yeast

    PubMed Central

    Mexia, Nikitia; Gaitanis, George; Velegraki, Aristea; Soshilov, Anatoly; Denison, Michael S.; Magiatis, Prokopios

    2015-01-01

    Malassezia furfur yeast strains isolated from diseased human skin preferentially biosynthesize indole alkaloids which can be detected in human skin and are highly potent activators of the aryl hydrocarbon receptor (AhR) and AhR-dependent gene expression. Chemical analysis of an EtOAc extract of a M. furfur strain obtained from diseased human skin and grown on L-tryptophan agar revealed several known AhR active tryptophan metabolites along with a previously unidentified compound, pityriazepin. While its structure resembled that of the known alkaloid pityriacitrin, the comprised pyridine ring had been transformed into an azepinone. The indoloazepinone scaffold of pityriazepin is extremely rare in nature and has only been reported once previously. Pityriazepin, like the other isolated compounds, was found to be a potent activator of the AhR-dependent reporter gene assays in recombinant cell lines derived from four different species, although significant species differences in relative potency was observed. The ability of pityriazepin to competitively bind to the AhR and directly stimulate AhR DNA binding classified it as a new naturally-occurring potent AhR agonist. Malassezia furfur produces an expanded collection of extremely potent naturally occurring AhR agonists, which produce their biological effects in a species-specific manner.1 PMID:25721496

  20. TCDD and omeprazole prime platelets through the aryl hydrocarbon receptor (AhR) non-genomic pathway.

    PubMed

    Pombo, Mónica; Lamé, Michael W; Walker, Naomi J; Huynh, Danh H; Tablin, Fern

    2015-05-19

    The role of the aryl hydrocarbon receptor (AhR) in hemostasis has recently gained increased attention. Here, we demonstrate, by qRT-PCR and western blot, that human platelets express both AhR mRNA and AhR protein. AhR protein levels increase in a dose dependent manner when incubated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or omeprazole. Treatment of platelets with puromycin blocks increased AhR protein synthesis in the presence of AhR activators. Additionally, treatment of platelets with either activator results in phosphorylation of p38MAPK and cPLA2, two key signaling molecules in platelet activation pathways. Using the AhR competitive inhibitors alpha naphthoflavone and CH-223191, we show that phosphorylation of p38MAPK is AhR dependent. Further, inhibition of p38MAPK blocks downstream cPLA2 phosphorylation induced by TCDD or omeprazole. Treatment with AhR activators results in platelet priming, as demonstrated by increased platelet aggregation, which is inhibited by AhR antagonists. Our data support a model of the platelet AhR non-genomic pathway in which treatment with AhR activators results in increased expression of the AhR, phosphorylation of p38MAPK and cPLA2, leading to platelet priming in response to agonist. PMID:25797602

  1. Detumbling and nutation canceling maneuvers with complete analytic reduction for axially symmetric spacecraft

    NASA Astrophysics Data System (ADS)

    Romano, Marcello

    2010-04-01

    A new method is introduced to control and analyze the rotational motion of an axially symmetric rigid-body spacecraft. In particular, this motion is seen as the combination of the rotation of a virtual sphere with respect to the inertial frame, and the rotation of the body, about its symmetry axis, with respect to this sphere. Two new exact solutions are introduced for the motion of axially symmetric rigid bodies subjected to a constant external torque in the following cases: (1) torque parallel to the angular momentum and (2) torque parallel to the vectorial component of the angular momentum on the plane perpendicular to the symmetry axis. By building upon these results, two rotational maneuvers are proposed for axially symmetric spacecraft: a detumbling maneuver and a nutation canceling maneuver. The two maneuvers are the minimum time maneuvers for spherically constrained maximum torque. These maneuvers are simple and elegant, as they reduce the control of the three degrees-of-freedom nonlinear rotational motion to a single degree-of-freedom linear problem. Furthermore, the complete (both for the dynamics and for the kinematics) and exact analytic solutions are found for the two maneuvers. An extended survey is reported in the introduction of the paper of the few cases where the rotation of a rigid body is fully reduced to an exact analytic solution in closed form.

  2. Precision Closed-Loop Orbital Maneuvering System Design and Performance for the Magnetospheric Multiscale Formation

    NASA Technical Reports Server (NTRS)

    Chai, Dean J.; Queen, Steven Z.; Placanica, Samuel J.

    2015-01-01

    NASAs Magnetospheric Multiscale (MMS) mission successfully launched on March 13,2015 (UTC) consists of four identically instrumented spin-stabilized observatories that function as a constellation to study magnetic reconnection in space. The need to maintain sufficiently accurate spatial and temporal formation resolution of the observatories must be balanced against the logistical constraints of executing overly-frequent maneuvers on a small fleet of spacecraft. These two considerations make for an extremely challenging maneuver design problem. This paper focuses on the design elements of a 6-DOF spacecraft attitude control and maneuvering system capable of delivering the high-precision adjustments required by the constellation designers specifically, the design, implementation, and on-orbit performance of the closed-loop formation-class maneuvers that include initialization, maintenance, and re-sizing. The maneuvering control system flown on MMS utilizes a micro-gravity resolution accelerometer sampled at a high rate in order to achieve closed-loop velocity tracking of an inertial target with arc-minute directional and millimeter-per second magnitude accuracy. This paper summarizes the techniques used for correcting bias drift, sensor-head offsets, and centripetal aliasing in the acceleration measurements. It also discusses the on-board pre-maneuver calibration and compensation algorithms as well as the implementation of the post-maneuver attitude adjustments.

  3. Inlet Flow Characteristics During Rapid Maneuvers for an F/A-18A Airplane

    NASA Technical Reports Server (NTRS)

    Steenken, William G.; Williams, John G.; Walsh, Kevin R.

    1999-01-01

    The F404-GE-400 engine powered F/A-18A High Alpha Research Vehicle (HARV) was used to examine the characteristics of inlet airflow during rapid aircraft maneuvers. A study of the degree of similarity between inlet data obtained during rapid aircraft maneuvers and inlet data obtained at steady aerodynamic attitudes was conducted at the maximum engine airflow of approximately 145 Ibm/sec using a computer model that was generated from inlet data obtained during steady aerodynamic maneuvers. Results show that rapid-maneuver inlet recoveries agreed very well with the recoveries obtained at equivalent stabilized angle-of-attack conditions. The peak dynamic circumferential distortion values obtained during rapid maneuvers agreed within 0.01 units of distortion over the 10 - 38 degree angle of attack range with the values obtained during steady aerodynamic maneuvers while similar agreement was found for the peak dynamic radial distortion values up to 29 degrees angle-of-attack. Exceedences of the rapid-maneuver peak dynamic circumferential distortion values relative to the peak distortion model values at steady attitudes occurred only at low or negative angles of attack and were inconsequential from an engine-stability assessment point of view. The results of this study validate the current industry practice of testing at steady aerodynamic conditions to characterize inlet recovery and peak dynamic distortion levels.

  4. A Monte Carlo error analysis program for near-Mars, finite-burn, orbital transfer maneuvers

    NASA Technical Reports Server (NTRS)

    Green, R. N.; Hoffman, L. H.; Young, G. R.

    1972-01-01

    A computer program was developed which performs an error analysis of a minimum-fuel, finite-thrust, transfer maneuver between two Keplerian orbits in the vicinity of Mars. The method of analysis is the Monte Carlo approach where each off-nominal initial orbit is targeted to the desired final orbit. The errors in the initial orbit are described by two covariance matrices of state deviations and tracking errors. The function of the program is to relate these errors to the resulting errors in the final orbit. The equations of motion for the transfer trajectory are those of a spacecraft maneuvering with constant thrust and mass-flow rate in the neighborhood of a single body. The thrust vector is allowed to rotate in a plane with a constant pitch rate. The transfer trajectory is characterized by six control parameters and the final orbit is defined, or partially defined, by the desired target parameters. The program is applicable to the deboost maneuver (hyperbola to ellipse), orbital trim maneuver (ellipse to ellipse), fly-by maneuver (hyperbola to hyperbola), escape maneuvers (ellipse to hyperbola), and deorbit maneuver.

  5. Activation of the Ah receptor by extracts of dietary herbal supplements, vegetables, and fruits.

    PubMed

    Jeuken, Anoek; Keser, Bart J G; Khan, Elaine; Brouwer, Abraham; Koeman, Jan; Denison, Michael S

    2003-08-27

    The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that can be activated by a structurally diverse range of synthetic and natural chemicals, and it mediates the toxic and biological effects of environmental contaminants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The spectrum of chemicals that bind to and activate the AhR signal transduction pathway and the identity of materials containing AhR active chemicals is only now being defined. Utilizing AhR-dependent gel retardation and reporter gene bioassays, the screening of extracts of 22 dietary herbal supplements and 21 food products (vegetables and fruits) was performed to identify those containing AhR agonists. Several herbal extracts (ginseng, Fo-Ti, white oak bark, licorice, ginkgo biloba, and black cohosh) stimulated AhR DNA binding and gene expression to levels between 20 and 60% of that produced by TCDD. Although some food extracts (corn, jalapeño pepper, green bell pepper, apple, Brussels sprout, and potato) were relatively potent activators of AhR DNA binding (30-50% of TCDD), only corn and jalapeño pepper extracts induced AhR-dependent luciferase reporter gene expression. However, dilution of corn, jalapeño pepper, bell pepper, and potato extracts dramatically increased their ability to induce luciferase activity, suggesting that these extracts contained AhR antagonists whose effectiveness was overcome by dilution. Overall, these results demonstrate that dietary products can be a major source of naturally occurring AhR ligands to which animals and humans are chronically exposed. PMID:12926901

  6. Aryl Hydrocarbon Receptor (AhR) Regulates Silica-Induced Inflammation But Not Fibrosis

    PubMed Central

    Beamer, Celine A.; Seaver, Benjamin P.; Shepherd, David M.

    2012-01-01

    The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, is responsible for mediating a variety of pharmacological and toxicological effects caused by halogenated aromatic hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, recent evidence has revealed that the AhR also has numerous physiological roles aside from xenobiotic metabolism, including regulation of immune and inflammatory signaling as well as normal development and homeostasis of several organs. To investigate the role of the AhR in crystalline silica (SiO2)–induced inflammation and fibrosis, C57Bl/6 and AhR−/− mice were exposed to SiO2 or vehicle. Similarly, C57Bl/6 mice were exposed to SiO2 and TCDD either simultaneously or sequentially to assess whether AhR activation alters inflammation and fibrosis. SiO2-induced acute lung inflammation was more severe in AhR−/− mice; however, the fibrotic response of AhR−/− mice was attenuated compared with C57Bl/6 mice. In a model of chronic SiO2 exposure, AhR activation by TCDD in C57Bl/6 mice resulted in reduced inflammation; however, the fibrotic response was not affected. Bone marrow–derived macrophages (BMM) from AhR−/− mice also produced higher levels of cytokines and chemokines in response to SiO2. Analysis of gene expression revealed that BMM derived from AhR−/− mice exhibit increased levels of pro-interleukin (IL)-1β, IL-6, and Bcl-2, yet decreased levels of signal transducers and activators of transcription (STAT)2, STAT5a, and serpin B2 (Pai-2) in response to SiO2. PMID:22273745

  7. Adapting Covariance Propagation to Account for the Presence of Modeled and Unmodeled Maneuvers

    NASA Technical Reports Server (NTRS)

    Schiff, Conrad

    2006-01-01

    This paper explores techniques that can be used to adapt the standard linearized propagation of an orbital covariance matrix to the case where there is a maneuver and an associated execution uncertainty. A Monte Carlo technique is used to construct a final orbital covariance matrix for a 'propagate-burn-propagate' process that takes into account initial state uncertainty and execution uncertainties in the maneuver magnitude. This final orbital covariance matrix is regarded as 'truth' and comparisons between it and three methods using modified linearized covariance propagation are made. The first method accounts for the maneuver by modeling its nominal effect within the state transition matrix but excludes the execution uncertainty by omitting a process noise matrix from the computation. In the second method, the maneuver is not modeled but the uncertainty in its magnitude is accounted for by the inclusion of a process noise matrix. In the third method, which is essentially a hybrid of the first two, the nominal portion of the maneuver is included via the state transition matrix while a process noise matrix is used to account for the magnitude uncertainty. Since this method also correctly accounts for the presence of the maneuver in the nominal orbit, it is the best method for applications involving the computation of times of closest approach and the corresponding probability of collision, Pc. However, applications for the two other methods exist and are briefly discussed. Despite the fact that the process model ('propagate-burn-propagate') that was studied was very simple - point-mass gravitational effects due to the Earth combined with an impulsive delta-V in the velocity direction for the maneuver - generalizations to more complex scenarios, including high fidelity force models, finite duration maneuvers, and maneuver pointing errors, are straightforward and are discussed in the conclusion.

  8. Detection of mild to moderate influenza A/H7N9 infection by China’s national sentinel surveillance system for influenza-like illness: case series

    PubMed Central

    Ip, Dennis KM; Liao, Qiaohong; Wu, Peng; Gao, Zhancheng; Cao, Bin; Feng, Luzhao; Xu, Xiaoling; Jiang, Hui; Li, Ming; Bao, Jing; Zheng, Jiandong; Zhang, Qian; Chang, Zhaorui; Li, Yu; Liu, Fengfeng; Ni, Michael Y; Wu, Joseph T; Cowling, Benjamin J; Yang, Weizhong

    2013-01-01

    Objective To characterise the complete case series of influenza A/H7N9 infections as of 27 May 2013, detected by China’s national sentinel surveillance system for influenza-like illness. Design Case series. Setting Outpatient clinics and emergency departments of 554 sentinel hospitals across 31 provinces in mainland China. Cases Infected individuals were identified through cross-referencing people who had laboratory confirmed A/H7N9 infection with people detected by the sentinel surveillance system for influenza-like illness, where patients meeting the World Health Organization’s definition of influenza-like illness undergo weekly surveillance, and 10-15 nasopharyngeal swabs are collected each week from a subset of patients with influenza-like illness in each hospital for virological testing. We extracted relevant epidemiological data from public health investigations by the Centers for Disease Control and Prevention at the local, provincial, and national level; and clinical and laboratory data from chart review. Main outcome measure Epidemiological, clinical, and laboratory profiles of the case series. Results Of 130 people with laboratory confirmed A/H7N9 infection as of 27 May 2013, five (4%) were detected through the sentinel surveillance system for influenza-like illness. Mean age was 13 years (range 2-26), and none had any underlying medical conditions. Exposure history, geographical location, and timing of symptom onset of these five patients were otherwise similar to the general cohort of laboratory confirmed cases so far. Only two of the five patients needed hospitalisation, and all five had mild or moderate disease with an uneventful course of recovery. Conclusion Our findings support the existence of a “clinical iceberg” phenomenon in influenza A/H7N9 infections, and reinforce the need for vigilance to the diverse presentation that can be associated with A/H7N9 infection. At the public health level, indirect evidence suggests a substantial

  9. Near minimum-time maneuvers of large space structures using parameter optimization

    NASA Technical Reports Server (NTRS)

    Carter, M. T.; Vadali, S. R.; Singh, T.

    1993-01-01

    Near minimum-time attitude maneuvers for large, inherently-flexible space structures with finite fuel supplies are investigated. The open loop maneuver is determined with the Sequential Quadratic Programming (SQP) algorithm, which optimizes a bang-off-bang control parameter set for the given maneuver. Torque smoothing is used to prevent discontinuities in the control which would excite the flexible structure. Additional system dynamics such as thruster inefficiency, spring forces and pressure leaks are identified from preliminary experiments on the ASTREX test article.

  10. A pilot in the loop analysis of helicopter acceleration/deceleration maneuvers

    NASA Technical Reports Server (NTRS)

    Heffley, R. K.

    1982-01-01

    Helicopter flight acceleration/deceleration maneuvers are quantified and put to use in the fields of handling qualities, flight training and evaluation of simulator fidelity. The three specific cases include the normal speed change maneuver, the nap-of-the-Earth dash/quickstop, and the decelerating approach to hover. All of these maneuvers share common generic features in terms of pilot adaptation and mathematical description; yet each differs in terms of the essential feedback loop structure, implications for handling qualities requirements, and simulator fidelity criteria.

  11. Unscented fuzzy-controlled current statistic model and adaptive filtering for tracking maneuvering targets

    NASA Astrophysics Data System (ADS)

    Hu, Hongtao; Jing, Zhongliang; Hu, Shiqiang

    2006-12-01

    A novel adaptive algorithm for tracking maneuvering targets is proposed. The algorithm is implemented with fuzzy-controlled current statistic model adaptive filtering and unscented transformation. A fuzzy system allows the filter to tune the magnitude of maximum accelerations to adapt to different target maneuvers, and unscented transformation can effectively handle nonlinear system. A bearing-only tracking scenario simulation results show the proposed algorithm has a robust advantage over a wide range of maneuvers and overcomes the shortcoming of the traditional current statistic model and adaptive filtering algorithm.

  12. Effects of automobile steering characteristics on driver/vehicle system performance in discrete maneuvers

    NASA Technical Reports Server (NTRS)

    Klein, R. H.; Mcruer, D. T.

    1975-01-01

    A series of discrete maneuver tasks were used to evaluate the effects of steering gain and directional mode dynamic parameters on driver/vehicle responses. The importance and ranking of these parameters were evaluated through changes in subjective driver ratings and performance measures obtained from transient maneuvers such as a double lane change, an emergency lane change, and an unexpected obstacle. The unexpected obstacle maneuver proved more sensitive to individual driver differences than to vehicle differences. Results were based on full scale tests with an experienced test driver evaluating many different dynamic configurations plus seventeen ordinary drivers evaluating six key configurations.

  13. On-orbit performance of the Skylab astronaut maneuvering research vehicle

    NASA Technical Reports Server (NTRS)

    Murtagh, T. B.; Mccandless, B., II; Whitsett, C. E.; Josephson, J. T.

    1974-01-01

    The present work evaluates the results of flight tests of the Astronaut Maneuvering Research Vehicle (AMRV) conducted inside the Skylab Orbital Workshop. The vehicle is an autonomous mobility aid which allows the pilot to control his position and orientation in space without the necessity of reacting against the spacecraft. The purpose of the tests was to obtain operation experience and engineering/human performance data in a zero gravity environment, to correlate on-orbit data with simulation data, and to recommend a design configuration for future operational maneuvering units. Four different techniques for controlling AMRV dynamics were tested: hand-held maneuvering unit, direct, rate gyro, and control moment gyro operating modes.

  14. High alpha feedback control for agile half-loop maneuvers of the F-18 airplane

    NASA Technical Reports Server (NTRS)

    Stalford, Harold

    1988-01-01

    A nonlinear feedback control law for the F/A-18 airplane that provides time-optimal or agile maneuvering of the half-loop maneuver at high angles of attack is given. The feedback control law was developed using the mathematical approach of singular perturbations, in which the control devices considered were conventional aerodynamic control surfaces and thrusting. The derived nonlinear control law was used to simulate F/A-18 half-loop maneuvers. The simulated results at Mach 0.6 and 0.9 compared well with pilot simulations conducted at NASA.

  15. Annihilation of angular momentum bias during thrusting and spinning-up maneuvers

    NASA Technical Reports Server (NTRS)

    Longuski, J. M.; Kia, T.; Breckenridge, W. G.

    1989-01-01

    During spinning-up and thrusting maneuvers of rockets and spacecraft, undesired transverse torques (from error sources such as thruster misalignment, center-of-mass offset and thruster mismatch) perturb the angular momentum vector from its original orientation. In this paper a maneuver scheme is presented which virtually annihilates the angular momentum vector bias, even though the magnitude and direction of the perturbing body-fixed torques are unknown. In the analysis it is assumed that the torques are small and constant and that the spacecraft or rocket can be approximated by a rigid body, which may be asymmetric. Typical maneuvers of the Galileo spacecraft are simulated to demonstrate the technique.

  16. Passenger comfort during terminal-area flight maneuvers. M.S. Thesis.

    NASA Technical Reports Server (NTRS)

    Schoonover, W. E., Jr.

    1976-01-01

    A series of flight experiments was conducted to obtain passenger subjective responses to closely controlled and repeatable flight maneuvers. In 8 test flights, reactions were obtained from 30 passenger subjects to a wide range of terminal-area maneuvers, including descents, turns, decelerations, and combinations thereof. Analysis of the passenger rating variance indicated that the objective of a repeatable flight passenger environment was achieved. Multiple linear regression models developed from the test data were used to define maneuver motion boundaries for specified degrees of passenger acceptance.

  17. Development and flight test of an experimental maneuver autopilot for a highly maneuverable aircraft

    NASA Technical Reports Server (NTRS)

    Duke, Eugene L.; Jones, Frank P.; Roncoli, Ralph B.

    1986-01-01

    This report presents the development of an experimental flight test maneuver autopilot (FTMAP) for a highly maneuverable aircraft. The essence of this technique is the application of an autopilot to provide precise control during required flight test maneuvers. This newly developed flight test technique is being applied at the Dryden Flight Research Facility of NASA Ames Research Center. The FTMAP is designed to increase the quantity and quality of data obtained in test flight. The technique was developed and demonstrated on the highly maneuverable aircraft technology (HiMAT) vehicle. This report describes the HiMAT vehicle systems, maneuver requirements, FTMAP development process, and flight results.

  18. Aminoflavone, a ligand of the Aryl Hydrocarbon Receptor (AhR), inhibits HIF-1α expression in an AhR-independent fashion

    PubMed Central

    Terzuoli, Erika; Puppo, Maura; Rapisarda, Annamaria; Uranchimeg, Badarch; Cao, Liang; Burger, Angelika M.; Ziche, Marina; Melillo, Giovanni

    2010-01-01

    Aminoflavone (AF), the active component of a novel anticancer agent (AFP464) in phase I clinical trials, is a ligand of the aryl hydrocarbon receptor (AhR). AhR dimerizes with HIF-1β/ARNT, which is shared with HIF-1α, a transcription factor critical for the response of cells to oxygen deprivation. To address whether pharmacological activation of the AhR pathway might be a potential mechanism for inhibition of HIF-1, we tested the effects of AF on HIF-1 expression. AF inhibited HIF-1α transcriptional activity and protein accumulation in MCF-7 cells. However, inhibition of HIF-1α by AF was independent from a functional AhR pathway. Indeed, AF inhibited HIF-1α expression in AhR100 cells, in which the AhR pathway is functionally impaired, yet did not induce cytotoxicity, providing evidence that these effects are mediated by distinct signaling pathways. Moreover, AF was inactive in MDA-MB-231 cells, yet inhibited HIF-1α in MDA-MB-231 cells transfected with the SULT1A1 gene. AF inhibited HIF-1α mRNA expression by approximately 50%. Notably, actinomycin-D completely abrogated the ability of AF to down-regulate HIF-1α mRNA, indicating that active transcription was required for the inhibition of HIF-1α expression. Finally, AF inhibited HIF-1α protein accumulation and the expression of HIF-1-target genes in MCF-7 xenografts. These results demonstrate that AF inhibits HIF-1α in an AhR-independent fashion and they unveil additional activities of AF that may be relevant for its further clinical development. PMID:20736373

  19. Computation of Hypersonic Flow about Maneuvering Vehicles with Changing Shapes

    SciTech Connect

    Ferencz, R M; Felker, F F; Castillo, V M

    2004-02-23

    Vehicles moving at hypersonic speeds have great importance to the National Security. Ballistic missile re-entry vehicles (RV's) travel at hypersonic speeds, as do missile defense intercept vehicles. Despite the importance of the problem, no computational analysis method is available to predict the aerodynamic environment of maneuvering hypersonic vehicles, and no analysis is available to predict the transient effects of their shape changes. The present state-of-the-art for hypersonic flow calculations typically still considers steady flow about fixed shapes. Additionally, with present computational methods, it is not possible to compute the entire transient structural and thermal loads for a re-entry vehicle. The objective of this research is to provide the required theoretical development and a computational analysis tool for calculating the hypersonic flow about maneuvering, deforming RV's. This key enabling technology will allow the development of a complete multi-mechanics simulation of the entire RV flight sequence, including important transient effects such as complex flight dynamics. This will allow the computation of the as-delivered state of the payload in both normal and unusual operational environments. This new analysis capability could also provide the ability to predict the nonlinear, transient behavior of endo-atmospheric missile interceptor vehicles to the input of advanced control systems. Due to the computational intensity of fluid dynamics for hypersonics, the usual approach for calculating the flow about a vehicle that is changing shape is to complete a series of steady calculations, each with a fixed shape. However, this quasi-steady approach is not adequate to resolve the frequencies characteristic of a vehicle's structural dynamics. Our approach is to include the effects of the unsteady body shape changes in the finite-volume method by allowing for arbitrary translation and deformation of the control volumes. Furthermore, because the Eulerian

  20. Techniques for Improving the Performance of Future EVA Maneuvering Systems

    NASA Technical Reports Server (NTRS)

    Williams, Trevor W.

    1995-01-01

    The Simplified Aid for EVA Rescue (SAFER) is a small propulsive backpack that was developed as an in-house effort at Johnson Space Center; it is a lightweight system which attaches to the underside of the Primary Life Support Subsystem (PLSS) backpack of the Extravehicular Mobility Unit (EMU). SAFER provides full six-axis control, as well as Automatic Attitude Hold (AAH), by means of a set of cold-gas nitrogen thrusters and a rate sensor-based control system. For compactness, a single hand controller is used, together with mode switching, to command all six axes. SAFER was successfully test-flown on the STS-64 mission in September 1994 as a Development Test Objective (DTO); development of an operational version is now proceeding. This version will be available for EVA self-rescue on the International Space Station and Mir, starting with the STS-86/Mir-7 mission in September 1997. The DTO SAFER was heavily instrumented, and produced in-flight data that was stored in a 12 MB computer memory on-board. This has allowed post-flight analysis to yield good estimates for the actual mass properties (moments and products of inertia and center of mass location) encountered on-orbit. By contrast, Manned Maneuvering Unit (MMU) post-flight results were generated mainly from analysis of video images, and so were not very accurate. The main goal of the research reported here was to use the detailed SAFER on-orbit mass properties data to optimize the design of future EVA maneuvering systems, with the aim being to improve flying qualities and/or reduce propellant consumption. The Automation, Robotics and Simulation Division Virtual Reality (VR) Laboratory proved to be a valuable research tool for such studies. A second objective of the grant was to generate an accurate dynamics model in support of the reflight of the DTO SAFER on STS-76/Mir-3. One complicating factor was the fact that a hand controller stowage box was added to the underside of SAFER on this flight; the position of

  1. Orbital transfer vehicle concept definition and system analysis study. Volume 2: OTV concept definition and evaluation. Book 1: Mission and system requirements

    NASA Technical Reports Server (NTRS)

    Kofal, Allen E.

    1987-01-01

    The mission and system requirements for the concept definition and system analysis of the Orbital Transfer Vehicle (OTV) are established. The requirements set forth constitute the single authority for the selection, evaluation, and optimization of the technical performance and design of the OTV. This requirements document forms the basis for the Ground and Space Based OTV concept definition analyses and establishes the physical, functional, performance and design relationships to STS, Space Station, Orbital Maneuvering Vehicle (OMV), and payloads.

  2. Characterization of drug-resistant influenza virus A(H1N1) and A(H3N2) variants selected in vitro with laninamivir.

    PubMed

    Samson, Mélanie; Abed, Yacine; Desrochers, François-Marc; Hamilton, Stephanie; Luttick, Angela; Tucker, Simon P; Pryor, Melinda J; Boivin, Guy

    2014-09-01

    Neuraminidase inhibitors (NAIs) play a major role for managing influenza virus infections. The widespread oseltamivir resistance among 2007-2008 seasonal A(H1N1) viruses and community outbreaks of oseltamivir-resistant A(H1N1)pdm09 strains highlights the need for additional anti-influenza virus agents. Laninamivir is a novel long-lasting NAI that has demonstrated in vitro activity against influenza A and B viruses, and its prodrug (laninamivir octanoate) is in phase II clinical trials in the United States and other countries. Currently, little information is available on the mechanisms of resistance to laninamivir. In this study, we first performed neuraminidase (NA) inhibition assays to determine the activity of laninamivir against a set of influenza A viruses containing NA mutations conferring resistance to one or many other NAIs. We also generated drug-resistant A(H1N1) and A(H3N2) viruses under in vitro laninamivir pressure. Laninamivir demonstrated a profile of susceptibility that was similar to that of zanamivir. More specifically, it retained activity against oseltamivir-resistant H275Y and N295S A(H1N1) variants and the E119V A(H3N2) variant. In vitro, laninamivir pressure selected the E119A NA substitution in the A/Solomon Islands/3/2006 A(H1N1) background, whereas E119K and G147E NA changes along with a K133E hemagglutinin (HA) substitution were selected in the A/Quebec/144147/2009 A(H1N1)pdm09 strain. In the A/Brisbane/10/2007 A(H3N2) background, a large NA deletion accompanied by S138A/P194L HA substitutions was selected. This H3N2 variant had altered receptor-binding properties and was highly resistant to laninamivir in plaque reduction assays. Overall, we confirmed the similarity between zanamivir and laninamivir susceptibility profiles and demonstrated that both NA and HA changes can contribute to laninamivir resistance in vitro. PMID:24957832

  3. The 50 Ah NiH2 CPV qualification tests

    NASA Technical Reports Server (NTRS)

    Garner, J. C.; Barnes, Wilbert L.; Hickman, Gary L.

    1995-01-01

    In 1992, the Naval Research Laboratory (NRL) started a program to qualify a large diameter common pressure vessel (CPV) nickel-hydrogen (NiH2) batteries for use on future Navy/NRL spacecraft electrical power subsystems. NRL's involvement with the qualification of CPV NiH2 batteries dates back to 1988 when COMSAT and Johnson Controls, Inc. initiated a joint effort to fly the first ever NiH2 CPV in space. A later NRL-JCI cooperative research and development agreement led to the launch of a space experiment in 1993 and to the use of a single NiH2 CPV battery on the BMDO Clementine spacecraft in 1994. NRL initiated procurement of two, 50 Ah CPV NiH2 batteries in the Fall of 1992. The two batteries were delivered to NRL in June 1994. NiH2 CPV batteries have almost 2x the specific energy (Wh/kg) of nickel cadium batteries and 2x the energy density (Wh/l) of individual pressure vessel NiH2 CPV's. This presentation discusses the results of electrical and mechanical qualification tests conducted at NRL. The tests included electrical characterization, standard capacity, random vibration, peak load, and thermal vacuum. The last slides of the presentation show initial results from the life cycle tests of the second NiH2 CPV battery at 40% depth of discharge and a temperature of 10 C.

  4. Nodulisporiviridins A-H, Bioactive Viridins from Nodulisporium sp.

    PubMed

    Zhao, Qin; Chen, Guo-Dong; Feng, Xiao-Lin; Yu, Yang; He, Rong-Rong; Li, Xiao-Xia; Huang, Yan; Zhou, Wen-Xia; Guo, Liang-Dong; Zheng, Yi-Zhi; Yao, Xin-Sheng; Gao, Hao

    2015-06-26

    Eight new viridins, nodulisporiviridins A-H (1-8), were isolated from the extract of an endolichenic fungal strain Nodulisporium sp. (No. 65-17-2-1) that was fermented with potato-dextrose broth. The structures were determined using spectroscopic and X-ray crystallographic analysis. Nodulisporiviridins A-D (1-4) are unique viridins with an opened ring A. The Aβ42 aggregation inhibitory activities of 1-8 were evaluated using a thioflavin T (ThT) assay with epigallocatechin gallate (EGCG) as the positive control (EGCG IC50 of 0.5 μM). Nodulisporiviridin G (7) displayed potent inhibitory activity with an IC50 value of 1.2 μM, and the preliminary trend of activity of these viridins as Aβ42 aggregation inhibitors was proposed. The short-term memory assay on an Aβ transgenic drosophila model of Alzheimer's disease showed that all eight compounds improved the short-term memory capacity, with potencies close to that of the positive control (memantine). PMID:25978520

  5. Space shuttle orbital maneuvering engine platelet injector program

    NASA Technical Reports Server (NTRS)

    1975-01-01

    A platelet face injector for the Orbit Maneuvering Engine (OME) on the space shuttle was evaluated as a means of obtaining additional design margin and lower cost. The program was conducted in three phases. The first phase evaluated single injection elements, or unielements; it involved visual flow studies, mixing experiments using propellant simulants, and hot firings to assess combustion efficiency, chamber wall compatibility, and injector face temperatures. In the second phase, subscale units producing 600 lbf thrust were used to further evaluate the orifice patterns chosen on the basis of unielement testing. In addition to combustion efficiency, chamber and injector heat transfer, the subscale testing provided a preliminary indication of injector stability. Full scale testing of the selected patterns at 6,000 lbf thrust was performed in the third phase. Performance, heat transfer, and combustion stability were evaluated over the anticipated range of OMS operating conditions. The effects on combustion stability of acoustic cavity configuration, including cavity depth, open area, inlet contour, and other parameters, were investigated.

  6. Independent Orbiter Assessment (IOA): Assessment of the manned maneuvering unit

    NASA Technical Reports Server (NTRS)

    Huynh, M.; Duffy, R. E.; Saiidi, M. J.

    1988-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA effort first completed an analysis of the Manned Maneuvering Unit (MMU) hardware, generating draft failure modes and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contain within the NASA FMEA/CIL documentation. The IOA results were then compared to the proposed Martin Marietta FMEA/CIL Post 51-L updates. A discussion of each discrepancy from the comparison is provided through additional analysis as required. These discrepancies were flagged as issues, and recommendations were made based on the FMEA data available at the time. The results of this comparison for the Orbiter MMU hardware are documented. The IOA product for the MMU analysis consisted of 204 failure mode worksheets that resulted in 95 potential critical items being identified. Comparison was made to the NASA baseline which consisted of 179 FMEAs and 110 CIL items. This comparison produced agreement on all 121 FMEAs which caused differences in 92 CIL items.

  7. OARE flight maneuvers and calibration measurements on STS-58

    NASA Technical Reports Server (NTRS)

    Blanchard, Robert C.; Nicholson, John Y.; Ritter, James R.; Larman, Kevin T.

    1994-01-01

    The Orbital Acceleration Research Experiment (OARE), which has flown on STS-40, STS-50, and STS-58, contains a three axis accelerometer with a single, nonpendulous, electrostatically suspended proofmass which can resolve accelerations to the nano-g level. The experiment also contains a full calibration station to permit in situ bias and scale factor calibration. This on-orbit calibration capability eliminates the large uncertainty of ground-based calibrations encountered with accelerometers flown in the past on the orbiter, thus providing absolute acceleration measurement accuracy heretofore unachievable. This is the first time accelerometer scale factor measurements have been performed on orbit. A detailed analysis of the calibration process is given along with results of the calibration factors from the on-orbit OARE flight measurements on STS-58. In addition, the analysis of OARE flight maneuver data used to validate the scale factor measurements in the sensor's most sensitive range is also presented. Estimates on calibration uncertainties are discussed. This provides bounds on the STS-58 absolute acceleration measurements for future applications.

  8. Maneuver simulations of flexible spacecraft by solving TPBVP

    NASA Technical Reports Server (NTRS)

    Bainum, Peter M.; Li, Feiyue

    1991-01-01

    The optimal control of large angle rapid maneuvers and vibrations of a Shuttle mast reflector system is considered. The nonlinear equations of motion are formulated by using Lagrange's formula, with the mast modeled as a continuous beam. The nonlinear terms in the equations come from the coupling between the angular velocities, the modal coordinates, and the modal rates. Pontryagin's Maximum Principle is applied to the slewing problem, to derive the necessary conditions for the optimal controls, which are bounded by given saturation levels. The resulting two point boundary value problem (TPBVP) is then solved by using the quasilinearization algorithm and the method of particular solutions. In the numerical simulations, the structural parameters and the control limits from the Spacecraft Control Lab Experiment (SCOLE) are used. In the 2-D case, only the motion in the plane of an Earth orbit or the single axis slewing motion is discussed. In the 3-D slewing, the mast is modeled as a continuous beam subjected to 3-D deformations. The numerical results for both the linearized system and the nonlinear system are presented to compare the differences in their time response.

  9. Application of a discretized vortex impulse framework to fish maneuvering

    NASA Astrophysics Data System (ADS)

    Mendelson, Leah; Techet, Alexandra

    2015-11-01

    In studies of biological propulsion, metrics for quantitative analysis of the vortex wake, including circulation, impulse, and their time derivatives, are a valuable indicator of performance. To better utilize volumetric PIV data in this type of analysis, a discretized method of deriving vortex impulse relying only on velocity data is developed. The impulse formulation is based on the geometry and distribution of circulation along the vortex core line, which can be detected using critical points in the velocity field. This analysis method is then applied to time-resolved velocity data of a turning giant danio (Devario aequipinnatus) and a jumping archer fish (Toxotes microlepis) obtained using Synthetic Aperture PIV (SAPIV). In the case of the danio, the vortex force vector derived from the impulse derivative shows good agreement with the kinematics of the fish tail during the turning maneuver. With the archer fish, the model is used to explore the relationship between the number of tail beats prior to the jump and the jump height.

  10. Flexible spacecraft maneuver - Inverse attitude control and modal stabilization

    NASA Technical Reports Server (NTRS)

    Singh, Sahjendra N.

    1988-01-01

    A control law is presented for three-axis rotational maneuvers of a spacecraft (orbiter)-beam-tip body (antenna or a reflector) configuration based on nonlinear inversion and modal velocity feedback. Using invertibility and functional reproducibility results, a decoupling attitude control law is presented such that, in the closed-loop system, the attitude angles of the spacecraft are independently controlled using the control moments acting on the space vehicle. This controller asymptotically decouples the flexible dynamics from the rigid one and also allows the decomposition of the elastic dynamics into two subsystems representing the transverse deflections of the beam in two orthogonal planes. These low-order subsystems are used for derivation of a modal velocity feedback stabilizer using the force and moment actuators at the end body. Simulation results are presented to show that, in the closed-loop system, attitude control and elastic mode stabilization are accomplished in spite of the parameter uncertainty and disturbance torque input in the system.

  11. Electromagnetic investigation at the Combat Maneuver Training Center, Hohenfels, Germany

    SciTech Connect

    Thompson, M.D.; Benson, M.A.; McGinnis, L.D.; Glennon, M.A.

    1997-10-01

    Electromagnetic surveys were conducted at the Combat Maneuver Training Center (CMTC), Hohenfels, Germany to detect zones where solution cavities develop within lowland areas of the karst valley systems. Geologic models indicate that solution activity occurs at the loess-bedrock interface, and is concentrated along loess-filled fracture trends within the underlying carbonate bedrock. Soil arches that develop along these fracture trends have the potential to fail catastrophically, posing a considerable degree of danger to current training activities. Rapid, continuously recording electromagnetic instruments provide an economical solution for locating zones of high conductivity associated with loess-filled fractures. The electromagnetic surveys delineated high-conductivity trends interpreted to be fracture-controlled. In many instances dolines were observed either along or immediately adjacent to these conductivity lineaments. Analysis of anomaly maps indicate that high-conductivity lineaments are aligned subparallel to fracture and joint orientations measured in nearby outcrops. These associations are the basis for predicting locations where solution cavity collapse and doline development will occur in the future. Information derived from the EM data can be extended directly to hydrologic modeling and to safety programs for military training at the CMTC.

  12. Linearizing Assumptions and Control Design for Spacecraft Formation Flying Maneuvers

    NASA Astrophysics Data System (ADS)

    Kappagantula, K. C.; Crassidis, J. L.

    In this paper the validity of neglecting the relative effect of the gravitational force of the Earth on a formation of spacecraft is studied. This relative effect is treated as an unknown disturbance acting on the system and all control laws are designed using a linear model that neglects this effect. A previously designed simple linear feedback controller is tested under different conditions using the linear model and the full nonlinear model that includes the gravitational force. All tests are carried out in the presence of saturation limits. The results show that the linear controller exhibits oscillations in the transient response and poor robustness under certain conditions. It also exhibits a high saturation tendency, thereby leading to increased fuel consumption. This controller also causes a high rise in the velocity errors at ordinary values of the gains. Based on the behavior of this controller, new controllers are proposed that overcome these drawbacks without any need for modifying the gains. The controllers, when tested under saturation limits exhibit high robustness characteristics due to their low saturation tendency and nearly eliminate oscillations in the transient response. Since these controllers operate under low control forces for a greater duration of the maneuver, they reduce the fuel required for the process. Simulation results are provided to show the effectiveness of these new controllers.

  13. Tactical approach to maneuvering within the chemical contamination labyrinth

    SciTech Connect

    Joseph, T.W.

    1990-12-31

    The Department of Energy (DOE) recognized the need and accepts the responsibility for understanding the reality and mitigating the consequence of the complex chemical contamination legacy it inherited as well as controlling, reducing, and eliminating extant emissions and effluents. The key to maneuvering through this complicated and multifaceted labyrinth of concerns, from which a meaningful, high quality, and cost-effective restoration/mitigation machine is then set in motions, is the ability to perform accurate, factual, and explicit health and environmental/ecological risk assessments. Likewise, the common denominator for carrying out this essential task is to have access to comprehensive and reliable data of known quality with which to perform those analyses. DOE is committed to identifying the data universe; to technically scrutinize and ensure the quality of that data; to develop efficient and cost-effective means to maximize the handling, utilization, and sharing of that universe; and to undertake those assessments. DOE views this as an effort that can only be accomplished through a merging of the technical excellence that exists within federal and state agencies, academia, and industry. The task at hand is so large that only by integrating that intelligence base can we hope to accomplish the goals of establishing meaningful standards, developing functional and effective solutions, and providing quality guidance at a national scale.

  14. Spacecraft Attitude Tracking and Maneuver Using Combined Magnetic Actuators

    NASA Technical Reports Server (NTRS)

    Zhou, Zhiqiang

    2012-01-01

    A paper describes attitude-control algorithms using the combination of magnetic actuators with reaction wheel assemblies (RWAs) or other types of actuators such as thrusters. The combination of magnetic actuators with one or two RWAs aligned with different body axis expands the two-dimensional control torque to three-dimensional. The algorithms can guarantee the spacecraft attitude and rates to track the commanded attitude precisely. A design example is presented for nadir-pointing, pitch, and yaw maneuvers. The results show that precise attitude tracking can be reached and the attitude- control accuracy is comparable with RWA-based attitude control. When there are only one or two workable RWAs due to RWA failures, the attitude-control system can switch to the control algorithms for the combined magnetic actuators with the RWAs without going to the safe mode, and the control accuracy can be maintained. The attitude-control algorithms of the combined actuators are derived, which can guarantee the spacecraft attitude and rates to track the commanded values precisely. Results show that precise attitude tracking can be reached, and the attitude-control accuracy is comparable with 3-axis wheel control.

  15. Spacecraft Attitude Tracking and Maneuver Using Combined Magnetic Actuators

    NASA Technical Reports Server (NTRS)

    Zhou, Zhiqiang

    2010-01-01

    The accuracy of spacecraft attitude control using magnetic actuators only is low and on the order of 0.4-5 degrees. The key reason is that the magnetic torque is two-dimensional and it is only in the plane perpendicular to the magnetic field vector. In this paper novel attitude control algorithms using the combination of magnetic actuators with Reaction Wheel Assembles (RWAs) or other types of actuators, such as thrusters, are presented. The combination of magnetic actuators with one or two RWAs aligned with different body axis expands the two-dimensional control torque to three-dimensional. The algorithms can guarantee the spacecraft attitude and rates to track the commanded attitude precisely. A design example is presented for Nadir pointing, pitch and yaw maneuvers. The results show that precise attitude tracking can be reached and the attitude control accuracy is comparable with RWAs based attitude control. The algorithms are also useful for the RWAs based attitude control. When there are only one or two workable RWAs due to RWA failures, the attitude control system can switch to the control algorithms for the combined magnetic actuators with the RWAs without going to the safe mode and the control accuracy can be maintained.

  16. Space shuttle orbit maneuvering engine reusable thrust chamber program

    NASA Technical Reports Server (NTRS)

    Senneff, J. M.

    1975-01-01

    Reusable thrust chamber and injector concepts were evaluated for the space shuttle orbit maneuvering engine (OME). Parametric engine calculations were carried out by computer program for N2O4/amine, LOX/amine and LOX/hydrocarbon propellant combinations for engines incorporating regenerative cooled and insulated columbium thrust chambers. The calculation methods are described including the fuel vortex film cooling method of combustion gas temperature control, and performance prediction. A method of acceptance of a regeneratively cooled heat rejection reduction using a silicone oil additive was also demonstrated by heated tube heat transfer testing. Regeneratively cooled thrust chamber operation was also demonstrated where the injector was characterized for the OME application with a channel wall regenerative thrust chamber. Bomb stability testing of the demonstration chambers/injectors demonstrated recovery for the nominal design of acoustic cavities. Cavity geometry changes were also evaluated to assess their damping margin. Performance and combustion stability was demonstrated of the originally developed 10 inch diameter combustion pattern operating in an 8 inch diameter thrust chamber.

  17. Evaluation and analysis of the orbital maneuvering vehicle video system

    NASA Technical Reports Server (NTRS)

    Moorhead, Robert J., II

    1989-01-01

    The work accomplished in the summer of 1989 in association with the NASA/ASEE Summer Faculty Research Fellowship Program at Marshall Space Flight Center is summarized. The task involved study of the Orbital Maneuvering Vehicle (OMV) Video Compression Scheme. This included such activities as reviewing the expected scenes to be compressed by the flight vehicle, learning the error characteristics of the communication channel, monitoring the CLASS tests, and assisting in development of test procedures and interface hardware for the bit error rate lab being developed at MSFC to test the VCU/VRU. Numerous comments and suggestions were made during the course of the fellowship period regarding the design and testing of the OMV Video System. Unfortunately from a technical point of view, the program appears at this point in time to be trouble from an expense prospective and is in fact in danger of being scaled back, if not cancelled altogether. This makes technical improvements prohibitive and cost-reduction measures necessary. Fortunately some cost-reduction possibilities and some significant technical improvements that should cost very little were identified.

  18. Open Platform for Limit Protection with Carefree Maneuver Applications

    NASA Technical Reports Server (NTRS)

    Jeram, Geoffrey J.

    2004-01-01

    This Open Platform for Limit Protection guides the open design of maneuver limit protection systems in general, and manned, rotorcraft, aerospace applications in particular. The platform uses three stages of limit protection modules: limit cue creation, limit cue arbitration, and control system interface. A common set of limit cue modules provides commands that can include constraints, alerts, transfer functions, and friction. An arbitration module selects the "best" limit protection cues and distributes them to the most appropriate control path interface. This platform adopts a holistic approach to limit protection whereby it considers all potential interface points, including the pilot's visual, aural, and tactile displays; and automatic command restraint shaping for autonomous limit protection. For each functional module, this thesis guides the control system designer through the design choices and information interfaces among the modules. Limit cue module design choices include type of prediction, prediction mechanism, method of critical control calculation, and type of limit cue. Special consideration is given to the nature of the limit, particularly the level of knowledge about it, and the ramifications for limit protection design, especially with respect to intelligent control methods such as fuzzy inference systems and neural networks.

  19. Computer simulation of on-orbit manned maneuvering unit operations

    NASA Technical Reports Server (NTRS)

    Stuart, G. M.; Garcia, K. D.

    1986-01-01

    Simulation of spacecraft on-orbit operations is discussed in reference to Martin Marietta's Space Operations Simulation laboratory's use of computer software models to drive a six-degree-of-freedom moving base carriage and two target gimbal systems. In particular, key simulation issues and related computer software models associated with providing real-time, man-in-the-loop simulations of the Manned Maneuvering Unit (MMU) are addressed with special attention given to how effectively these models and motion systems simulate the MMU's actual on-orbit operations. The weightless effects of the space environment require the development of entirely new devices for locomotion. Since the access to space is very limited, it is necessary to design, build, and test these new devices within the physical constraints of earth using simulators. The simulation method that is discussed here is the technique of using computer software models to drive a Moving Base Carriage (MBC) that is capable of providing simultaneous six-degree-of-freedom motions. This method, utilized at Martin Marietta's Space Operations Simulation (SOS) laboratory, provides the ability to simulate the operation of manned spacecraft, provides the pilot with proper three-dimensional visual cues, and allows training of on-orbit operations. The purpose here is to discuss significant MMU simulation issues, the related models that were developed in response to these issues and how effectively these models simulate the MMU's actual on-orbiter operations.

  20. Atmospheric environment during maneuvering descent from Martian orbit

    NASA Technical Reports Server (NTRS)

    Tauber, Michael E.; Bowles, Jeffrey V.; Yang, Lily

    1989-01-01

    This paper presents an analysis of the atmospheric maneuvering capability of a vehicle designated to land on the Martian surface, together with an analysis of the entry environment encountered by the vehicle. A maximum lift/drag ratio of 2.3 was used for all trajectory calculations. The maximum achievable lateral ranges varied from about 3400 km to 2500 km for entry velocities of 5 km/s (from a highly elliptical Martian orbit) and 3.5 km/s (from a low-altitude lower-speed orbit), respectively. It is shown that the peak decelerations are an order of magnitude higher for the 5-km/s entries than for the 3.5-km/s entries. The vehicle entering at 3.5 km/s along a gliding trajectory encountered a much more benign atmospheric environment. In addition, the glider's peak deceleration was found to be only about 0.7 earth g, making the shallow flight path ideal for manned vehicles whose crews might be physically weakened by the long voyage to Mars.

  1. Lung recruitment maneuvers using direct ultrasound guidance: a case study.

    PubMed

    Du, Jiang; Tan, Jiuting; Yu, Kanglong; Wang, Ruilan

    2015-05-01

    Previous studies have shown that lung recruitment maneuvers are important means of treating ARDS. Although computed tomography (CT) scans and pressure-volume curves are the most common ways to evaluate lung recruitment, there are still many disadvantages. Not only do the scans have to take place in a CT room, but the patient is exposed to large doses of radiation through the multiple scans necessary to define the optimal PEEP. Pressure-volume curves require deep sedation and muscle relaxation. Thus, bedside lung ultrasound may be considered to be a safer and easier alternative to CT scans or pressure-volume curves. In our case, we evaluated the effectiveness of lung recruitment with a bedside ultrasound on a patient who was suffering from life-threatening hypoxemia. Bedside ultrasound is a faster and more convenient imaging method because it reduces the need for patient transport compared with CT scan and requires no muscle relaxation. This case supports that ultrasound may become an alternative imaging tool to guide and evaluate alveolar recruitment in patients with ARDS. Additionally, we have also included a brief review of lung recruitment evaluation by ultrasound to supplement this case study. PMID:25406343

  2. MEMS Reaction Control and Maneuvering for Picosat Beyond LEO

    NASA Technical Reports Server (NTRS)

    Alexeenko, Alina

    2016-01-01

    The MEMS Reaction Control and Maneuvering for Picosat Beyond LEO project will further develop a multi-functional small satellite technology for low-power attitude control, or orientation, of picosatellites beyond low Earth orbit (LEO). The Film-Evaporation MEMS Tunable Array (FEMTA) concept initially developed in 2013, is a thermal valving system which utilizes capillary forces in a microchannel to offset internal pressures in a bulk fluid. The local vapor pressure is increased by resistive film heating until it exceeds meniscus strength in a nozzle which induces vacuum boiling and provides a stagnation pressure equal to vapor pressure at that point which is used for propulsion. Interplanetary CubeSats can utilize FEMTA for high slew rate attitude corrections in addition to desaturating reaction wheels. The FEMTA in cooling mode can be used for thermal control during high-power communication events, which are likely to accompany the attitude correction. Current small satellite propulsion options are limited to orbit correction whereas picosatellites are lacking attitude control thrusters. The available attitude control systems are either quickly saturated reaction wheels or movable high drag surfaces with long response times.

  3. Support and maneuvering apparatus for solar energy receivers

    DOEpatents

    Murphy, Lawrence M.

    1989-01-01

    A support and maneuvering apparatus is disclosed for a solar energy receiving device adpated for receiving and concentrating solar energy and having a central axis extending through the center thereof. The apparatus includes a frame for mounting the perimeter of said solar energy receiving device. A support member extends along the central axis of the receiving device and has a base end passing through the center of the receiving device and an outer distal end adapted for carrying a solar energy receiving and conversion mechanism. A variable tension mechanism interconnects the support member with the frame to provide stiffening for the support member and the frame and to assist in the alignment of the frame to optimize the optical efficiency of the solar energy receiving device. A rotatable base is provided, and connecting members extend from the base for pivotable attachment to the frame at spaced positions therealong. Finally, an elevation assembly is connected to the receiving device for selectively pivoting the receiving device about an axis defined between the attachment positions of the connecting members on the frame.

  4. Support and maneuvering apparatus for solar energy receivers

    DOEpatents

    Murphy, L.M.

    1988-07-28

    A support and maneuvering apparatus is disclosed for a solar energy receiving device adapted for receiving and concentrating solar energy and having a central axis extending through the center thereof. The apparatus includes a frame for mounting the perimeter of said solar energy receiving device. A support member extends along the central axis of the receiving device and has a base end passing through the center of the receiving device and an outer distal end adapted for carrying a solar energy receiving and conversion mechanism. A variable tension mechanism interconnects the support member with the frame to provide stiffening for the support member and the frame and to assist in the alignment of the frame to optimize the optical efficiency of the solar energy receiving device. A rotatable base is provided, and connecting members extend from the base for pivotable attachment to the frame at spaced positions therealong. Finally, an elevation assembly is connected to the receiving device for selectively pivoting the receiving about an axis defined between the attachment positions of the connecting members on the frame. 4 figs.

  5. Effective Valsalva maneuvering during TCCD and unrevealed etiology of RLS.

    PubMed

    Aparci, M; Guney Senol, M; Yalcin, M; Tansel Kendirli, M; Isilak, Z

    2016-04-01

    Either transcranial color-coded Doppler (TCCD) or contrast echocardiography (CE) is the bests of clinically applicable and reproducible methods to evaluate the functionality of right-to-left shunts that can be found in different localization on atrial septum. As the anatomical features of right-to-left shunts could vary in many forms, detection of RLS by functional tests may aid the clinician to do risk prediction and management of patients. Sensitivity of TCDD or CE can be increased by performing effective Valsalva maneuvering during the test procedure. Timing of RLS during the cardiac cycles may help interpreting about the etiology of RLS, atrial septum or intrapulmonary shunts. Intrapulmonary shunts have been recently reported to be associated with RLS and frequently overlooked unless the tests prolonged up to 10th cardiac beat. Migraine, cryptogenic strokes, and paradoxic embolism are closely associated with RLS which should be evaluated by the collaboration of cardiologists and neurologists. Success of diagnostic procedure depends on high suspicion of index for RLS and application of contrast-enhanced tests that are effectively performed at each step. PMID:26935909

  6. 46 CFR 35.20-40 - Maneuvering characteristics-T/OC.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-40 Maneuvering characteristics—T/OC. For each ocean and coastwise tankship of 1,600 gross tons or...; (2) No current; (3) Deep water conditions—water depth twice the vessel's draft or greater; and...

  7. The foot-controlled maneuvering unit: Summary report on Skylab experiment T-020

    NASA Technical Reports Server (NTRS)

    Hewes, D. E.; Glover, K. E.

    1975-01-01

    Skylab experiment T-020 was conducted to study the maneuvering capabilities of astronauts using a relatively simple experimental self-locomotive device, referred to as the foot-controlled maneuvering unit, and to evaluate the effectiveness of ground-based facilities simulating the operation of this device in weightless conditions of space. The final results as presented of this experiment which includes comparison of the tests performed during missions SL-3 and SL-4 of the Skylab with those performed on the simulators. Some of the results of this experiment and those of Skylab experiment M509, which employed an experimental hard-controlled maneuvering unit, are discussed in terms of the development of a possible future operational maneuvering system.

  8. Aerodynamic Characteristics of an Aerospace Vehicle During a Subsonic Pitch-Over Maneuver

    NASA Technical Reports Server (NTRS)

    Kleb, William L.

    1996-01-01

    Time-dependent CFD has been used to predict aerospace vehicle aerodynamics during a subsonic rotation maneuver. The inviscid 3D3U code is employed to solve the 3-D unsteady flow field using an unstructured grid of tetrahedra. As this application represents a challenge to time-dependent CFD, observations concerning spatial and temporal resolution are included. It is shown that even for a benign rotation rate, unsteady aerodynamic effects are significant during the maneuver. Possibly more significant, however, the rotation maneuver creates ow asymmetries leading to yawing moment, rolling moment, and side force which are not present in the quasi-steady case. A series of steady solutions at discrete points in the maneuver are also computed for comparison with wind tunnel measurements and as a means of quantifying unsteady effects.

  9. Understanding the Role of Moment-of-Inertia Variation in Insect Flight Maneuvers

    NASA Astrophysics Data System (ADS)

    Lin, Tiras; Mittal, Rajat; Zheng, Lingxiao; Hedrick, Tyson

    2011-11-01

    The objective of this study is to gain insights into insect flight maneuvers and, in particular, the role that changes in body moment-of-inertia might play during these maneuvers. High-speed, high-resolution videogrammetry is used to quantify the trajectory and body conformation of Painted Lady butterflies during flight maneuvers; the 3D kinematics of the center-of-masses of the various body parts of the insect are determined experimentally. Measurements of the mass properties of the insect are then made and used to parameterize a simple flight dynamics model of the butterfly. Even though the mass of the flapping wings is small compared to the total mass of the insect, these experiments and subsequent analyses indicate that changes in moment-of-inertia during flight are large enough to have a noticeable impact on the maneuvers of these insects. Research is supported by NSF and AFOSR.

  10. A simulator investigation of air-to-air combat maneuvering for tilt-rotor aircraft

    NASA Technical Reports Server (NTRS)

    Decker, William A.; Isleib, Douglas; Johns, John

    1989-01-01

    As part of the Marine Corps's development of employment methods and maneuver techniques for the V-22 Osprey tilt-rotor aircraft, a piloted simulation study of one-on-one air-combat maneuvering (ACM) was conducted at NASA Ames. In addition to V-22 ACM, the simulation provided an opportunity for a preliminary investigation of maneuver requirements for a possible armed-escort tilt-rotor aircraft. Results from the study indicate that the tilt-rotor's low-speed masking and high-speed dash capabilities significantly enhance its survivability against both fixed-wing and helicopter aggressors. Furthermore, the tilt-rotor's conversion capability and, in turn, the variety and extent of its maneuvering characteristics make it an effective air-combat aircraft.

  11. Efficacy of Epley's Maneuver in Treating BPPV Patients: A Prospective Observational Study

    PubMed Central

    Gaur, Sushil; Awasthi, Sanjeev Kumar; Bhadouriya, Sunil Kumar Singh; Saxena, Rohit; Pathak, Vivek Kumar; Bisht, Mamta

    2015-01-01

    Vertigo and balance disorders are among the most common symptoms encountered in patients who visit ENT outpatient department. This is associated with risk of falling and is compounded in elderly persons with other neurologic deficits and chronic medical problems. BPPV is the most common cause of peripheral vertigo. BPPV is a common vestibular disorder leading to significant morbidity, psychosocial impact, and medical costs. The objective of Epley's maneuver, which is noninvasive, inexpensive, and easily administered, is to move the canaliths out of the canal to the utricle where they no longer affect the canal dynamics. Our study aims to analyze the response to Epley's maneuver in a series of patients with posterior canal BPPV and compares the results with those treated exclusively by medical management alone. Even though many studies have been conducted to prove the efficacy of this maneuver, this study reinforces the validity of Epley's maneuver by comparison with the medical management. PMID:26495002

  12. Meniscus delivery: a maneuver for easy arthroscopic access to the posterior horn of the medial meniscus

    PubMed Central

    Said, Hatem Galal; Goyal, Saumitra; Fetih, Tarek Nabil

    2016-01-01

    Pathology of posterior horn of medial meniscus is common and often presents a difficult approach during arthroscopy for various reasons. We describe an easy maneuver to facilitate “delivery of the medial meniscus” during arthroscopy. PMID:27163099

  13. 76 FR 8319 - Special Conditions: Gulfstream Model GVI Airplane; Design Roll Maneuver Requirement for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-14

    ... Roll Maneuver Requirement for Electronic Flight Controls AGENCY: Federal Aviation Administration (FAA... airplanes. These design features include an electronic flight control system that provides roll control of the airplane through pilot inputs to the flight ] computers. These proposed special conditions...

  14. Teleoperator Maneuvering System (TMS) benefits assessment study. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Teleoperator Maneuvering System (TMS) versus integral spacecraft propulsion, spacecraft maintenance, cost benefits, launch prices, integral propulsion length penalties, remote maintenance versus EVA, potential weight reduction benefits, basing mode, mission models and payload requirements, and program profitability are discussed.

  15. Global Optimization of N-Maneuver, High-Thrust Trajectories Using Direct Multiple Shooting

    NASA Technical Reports Server (NTRS)

    Vavrina, Matthew A.; Englander, Jacob A.; Ellison, Donald H.

    2015-01-01

    The performance of impulsive, gravity-assist trajectories often improves with the inclusion of one or more maneuvers between flybys. However, grid-based scans over the entire design space can become computationally intractable for even one deep-space maneuver, and few global search routines are capable of an arbitrary number of maneuvers. To address this difficulty a trajectory transcription allow-ing for any number of maneuvers is developed within a multi-objective, global optimization framework for constrained, multiple gravity-assist trajectories. The formulation exploits a robust shooting scheme and analytic derivatives for com-putational efficiency. The approach is applied to several complex, interplanetary problems, achieving notable performance without a user-supplied initial guess.

  16. Global Optimization of N-Maneuver, High-Thrust Trajectories Using Direct Multiple Shooting

    NASA Technical Reports Server (NTRS)

    Vavrina, Matthew A.; Englander, Jacob A.; Ellison, Donald H.

    2016-01-01

    The performance of impulsive, gravity-assist trajectories often improves with the inclusion of one or more maneuvers between flybys. However, grid-based scans over the entire design space can become computationally intractable for even one deep-space maneuver, and few global search routines are capable of an arbitrary number of maneuvers. To address this difficulty a trajectory transcription allowing for any number of maneuvers is developed within a multi-objective, global optimization framework for constrained, multiple gravity-assist trajectories. The formulation exploits a robust shooting scheme and analytic derivatives for computational efficiency. The approach is applied to several complex, interplanetary problems, achieving notable performance without a user-supplied initial guess.

  17. A Computer Simulation of the System-Wide Effects of Parallel-Offset Route Maneuvers

    NASA Technical Reports Server (NTRS)

    Lauderdale, Todd A.; Santiago, Confesor; Pankok, Carl

    2010-01-01

    Most aircraft managed by air-traffic controllers in the National Airspace System are capable of flying parallel-offset routes. This paper presents the results of two related studies on the effects of increased use of offset routes as a conflict resolution maneuver. The first study analyzes offset routes in the context of all standard resolution types which air-traffic controllers currently use. This study shows that by utilizing parallel-offset route maneuvers, significant system-wide savings in delay due to conflict resolution of up to 30% are possible. It also shows that most offset resolutions replace horizontal-vectoring resolutions. The second study builds on the results of the first and directly compares offset resolutions and standard horizontal-vectoring maneuvers to determine that in-trail conflicts are often more efficiently resolved by offset maneuvers.

  18. Method to maintain artificial gravity during transfer maneuvers for tethered spacecraft

    NASA Astrophysics Data System (ADS)

    Martin, Kaela M.; Landau, Damon F.; Longuski, James M.

    2016-03-01

    Artificial gravity has long been proposed to limit the harmful effects of the micro-gravity environment on human crews during mission to Mars. A tethered spacecraft spinning at 4 rpm (to avoid motion sickness) provides an attractive configuration. However, if the spacecraft is required to spin down for impulsive maneuvers and then spin up for interplanetary travel, the propellant cost may be unacceptably high. This paper proposes a maneuver that is performed while the spacecraft is spinning thus avoiding additional spin-down and spin-up maneuvers. A control law is provided to achieve the required ΔV while maintaining spin rate. A hypothetical human mission from Earth to Mars is analyzed using the new maneuver which, in this example, may save over 700 kg of propellant.

  19. Robust rendezvous maneuver point conditions. M.S. Thesis - Massachusetts Inst. of Tech.

    NASA Technical Reports Server (NTRS)

    Fogle, Debra Ann

    1992-01-01

    This study develops rendezvous maneuver point conditions that are robust to one dimensional errors in state estimation and burn execution. Allowing small deviations in the time of intercept provides a degree of freedom that can be used to compensate for these errors. The direction of allowable burn deviation is developed for errors in state estimation and burn execution. The maneuver points for which the error is aligned with the insensitive direction provide excellent rendezvous initiation points. The method is applied to sample rendezvous for vehicles in circular and elliptic orbits. Robust maneuver points are selected and the vehicles' relative motion plotted, demonstrating the validity of the maneuver points. Finally, a graphical illustration of the error focusing effect is demonstrated by means of a Monte Carlo simulation.

  20. The Maneuver Planning Process for the Microwave Anisotropy Probe (MAP) Mission

    NASA Technical Reports Server (NTRS)

    Mesarch, Michael A.; Andrews, Stephen; Bauer, Frank (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe (MAP) was successfully launched from Kennedy Space Center's Eastern Range on June 30, 2001. MAP will measure the cosmic microwave background as a follow up to NASA's Cosmic Background Explorer (COBE) mission from the early 1990's. MAP will take advantage of its mission orbit about the Sun-Earth/Moon L2 Lagrangian point to produce results with higher resolution, sensitivity, and accuracy than COBE. A strategy comprising highly eccentric phasing loops with a lunar gravity assist was utilized to provide a zero-cost insertion into a lissajous orbit about L2. Maneuvers were executed at the phasing loop perigees to correct for launch vehicle errors and to target the lunar gravity assist so that a suitable orbit at L2 was achieved. This paper will discuss the maneuver planning process for designing, verifying, and executing MAP's maneuvers. A discussion of the tools and how they interacted will also be included. The maneuver planning process was iterative and crossed several disciplines, including trajectory design, attitude control, propulsion, power, thermal, communications, and ground planning. Several commercial, off-the-shelf (COTS) packages were used to design the maneuvers. STK/Astrogator was used as the trajectory design tool. All maneuvers were designed in Astrogator to ensure that the Moon was met at the correct time and orientation to provide the energy needed to achieve an orbit about L2. The Mathworks Matlab product was used to develop a tool for generating command quaternions. The command quaternion table (CQT) was used to drive the attitude during the perigee maneuvers. The MatrixX toolset, originally written by Integrated Systems, Inc., now distributed by Mathworks, was used to create HiFi, a high fidelity simulator of the MAP attitude control system. HiFi was used to test the CQT and to make sure that all attitude requirements were met during the maneuver. In addition, all ACS data plotting and output were generated in

  1. Adapting Covariance Propagation to Account for the Presence of Modeled and Unmodeled Maneuvers

    NASA Technical Reports Server (NTRS)

    Schiff, Conrad

    2006-01-01

    This paper explores techniques that can be used to adapt the standard linearized propagation of an orbital covariance matrix to the case where there is a maneuver and an associated execution uncertainty. A Monte Carlo technique is used to construct a final orbital covariance matrix for a 'prop-burn-prop' process that takes into account initial state uncertainty and execution uncertainties in the maneuver magnitude. This final orbital covariance matrix is regarded as 'truth' and comparisons are made with three methods using modified linearized covariance propagation. The first method accounts for the maneuver by modeling its nominal effect within the state transition matrix but excludes the execution uncertainty by omitting a process noise matrix from the computation. The second method does not model the maneuver but includes a process noise matrix to account for the uncertainty in its magnitude. The third method, which is essentially a hybrid of the first two, includes the nominal portion of the maneuver via the state transition matrix and uses a process noise matrix to account for the magnitude uncertainty. The first method is unable to produce the final orbit covariance except in the case of zero maneuver uncertainty. The second method yields good accuracy for the final covariance matrix but fails to model the final orbital state accurately. Agreement between the simulated covariance data produced by this method and the Monte Carlo truth data fell within 0.5-2.5 percent over a range of maneuver sizes that span two orders of magnitude (0.1-20 m/s). The third method, which yields a combination of good accuracy in the computation of the final covariance matrix and correct accounting for the presence of the maneuver in the nominal orbit, is the best method for applications involving the computation of times of closest approach and the corresponding probability of collision, PC. However, applications for the two other methods exist and are briefly discussed. Although

  2. 46 CFR 35.20-40 - Maneuvering characteristics-T/OC.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Maneuvering characteristics-T/OC. 35.20-40 Section 35.20-40 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS OPERATIONS Navigation § 35.20-40 Maneuvering characteristics—T/OC. For each ocean and coastwise tankship of 1,600 gross tons or over, the following apply: (a) The...

  3. Alveolar recruitment maneuver and perioperative ventilatory support in obese patients undergoing abdominal surgery.

    PubMed

    Forgiarini Júnior, Luiz Alberto; Rezende, Juliana Castilhos; Forgiarini, Soraia Genebra Ibrahim

    2013-01-01

    The development of abdominal surgery represents an alternative therapy for the morbidly obese; however, patients undergoing this surgical procedure often experience postoperative pulmonary complications. The use of alveolar recruitment maneuvers and/or perioperative ventilatory strategies is a possible alternative to reduce these complications, focusing on the reduction of postoperative pulmonary complications. In this review, the benefits of perioperative ventilatory strategies and the implementation of alveolar recruitment maneuvers in obese patients undergoing abdominal surgery are described. PMID:24553513

  4. Alveolar recruitment maneuver and perioperative ventilatory support in obese patients undergoing abdominal surgery

    PubMed Central

    Forgiarini Júnior, Luiz Alberto; Rezende, Juliana Castilhos; Forgiarini, Soraia Genebra Ibrahim

    2013-01-01

    The development of abdominal surgery represents an alternative therapy for the morbidly obese; however, patients undergoing this surgical procedure often experience postoperative pulmonary complications. The use of alveolar recruitment maneuvers and/or perioperative ventilatory strategies is a possible alternative to reduce these complications, focusing on the reduction of postoperative pulmonary complications. In this review, the benefits of perioperative ventilatory strategies and the implementation of alveolar recruitment maneuvers in obese patients undergoing abdominal surgery are described. PMID:24553513

  5. Exact spacecraft maneuvers with jerk-free transition from thrusters to momentum wheels

    NASA Technical Reports Server (NTRS)

    Dwyer, T. A. W., III; Batten, A. L.

    1985-01-01

    A combined detumbling maneuver with constant but vectored external thrusters is presently followed, as in Dwyer and Batten (1985) by an exact reorientation that employs internal momentum transfer. Unlike the Dwyer and Batten technique, however, the proposed reorientation maneuver is of such a trajectory that spacecraft angular acceleration is preserved during the transition from thrusters to reaction wheels. This prevents jerk-driven excitation of unmodeled elastic modes.

  6. Combined control of fast attitude maneuver and stabilization for large complex spacecraft

    NASA Astrophysics Data System (ADS)

    Zhang, Yao; Zhang, Jing-Rui

    2013-12-01

    In remote sensing or laser communication space missions, spacecraft need fast maneuver and fast stabilization in order to accomplish agile imaging and attitude tracking tasks. However, fast attitude maneuvers can easily cause elastic deformations and vibrations in flexible appendages of the spacecraft. This paper focuses on this problem and deals with the combined control of fast attitude maneuver and stabilization for large complex spacecraft. The mathematical model of complex spacecraft with flexible appendages and momentum bias actuators on board is presented. Based on the plant model and combined with the feedback controller, modal parameters of the closed-loop system are calculated, and a multiple mode input shaper utilizing the modal information is designed to suppress vibrations. Aiming at reducing vibrations excited by attitude maneuver, a quintic polynomial form rotation path planning is proposed with constraints on the actuators and the angular velocity taken into account. Attitude maneuver simulation results of the control systems with input shaper or path planning in loop are separately analyzed, and based on the analysis, a combined control strategy is presented with both path planning and input shaper in loop. Simulation results show that the combined control strategy satisfies the complex spacecraft's requirement of fast maneuver and stabilization with the actuators' torque limitation satisfied at the same time.

  7. Adaptive Kalman filter implementation by a neural network scheme for tracking maneuvering targets

    NASA Astrophysics Data System (ADS)

    Amoozegar, Farid; Sundareshan, Malur K.

    1995-07-01

    Conventional target tracking algorithms based on linear estimation techniques perform quite efficiently when the target motion does not involve maneuvers. Target maneuvers involving short term accelerations, however, cause a bias (e.g. jump) in the measurement sequence, which unless compensated, results in divergence of the Kalman filter that provides estimates of target position and velocity, in turn leading to a loss of track. Accurate compensation for the bias requires processing more samples of the input signals which adds to the computational complexity. The waiting time for more samples can also result in a total loss of track since the target can begin a new maneuver and if the target begins a new maneuver before the first one is compensated for, the filter would never converge. Most of the proposed algorithms in the current literature hence have the disadvantage of losing the target in short term accelerations, i.e., when the duration of acceleration is comparable to the time period between the measurements. The time lag for maneuver modelings, which have been based on Bayesian probability calculations and linear estimation shall propose a neural network scheme for the modeling of target maneuvers. The primary motivation for employing compensation. The parallel processing capability of a properly trained neural network can permit fast processing of features to yield correct acceleration estimates and hence can take the burden off the primary Kalman filter which still provides the target position and velocity estimates.

  8. Effect of width and boundary conditions on meeting maneuvers on two-way separated cycle tracks.

    PubMed

    Garcia, Alfredo; Gomez, Fernando Agustin; Llorca, Carlos; Angel-Domenech, Antonio

    2015-05-01

    Cycle track design guidelines are rarely based on scientific studies. In the case of off-road two-way cycle tracks, a minimum width must facilitate both passing and meeting maneuvers, being meeting maneuvers the most frequent. This study developed a methodology to observe meeting maneuvers using an instrumented bicycle, equipped with video cameras, a GPS tracker, laser rangefinders and speed sensors. This bicycle collected data on six two-way cycle tracks ranging 1.3-2.15m width delimitated by different boundary conditions. The meeting maneuvers between the instrumented bicycle and every oncoming bicycle were characterized by the meeting clearance between the two bicycles, the speed of opposing bicycle and the reaction of the opposing rider: change in trajectory, stop pedaling or braking. The results showed that meeting clearance increased with the cycle track width and decreased if the cycle track had lateral obstacles, especially if they were higher than the bicycle handlebar. The speed of opposing bicycle shown the same tendency, although were more disperse. Opposing cyclists performed more reaction maneuvers on narrower cycle tracks and on cycle tracks with lateral obstacles to the handlebar height. Conclusions suggested avoiding cycle tracks narrower than 1.6m, as they present lower meeting clearances, lower bicycle speeds and frequent reaction maneuvers. PMID:25779982

  9. Species-Specific Differential AhR Expression Protects Human Neural Progenitor Cells against Developmental Neurotoxicity of PAHs

    PubMed Central

    Gassmann, Kathrin; Abel, Josef; Bothe, Hanno; Haarmann-Stemmann, Thomas; Merk, Hans F.; Quasthoff, Kim N.; Rockel, Thomas Dino; Schreiber, Timm; Fritsche, Ellen

    2010-01-01

    Background Because of their lipophilicity, persistent organic pollutants (POPs) cross the human placenta, possibly affecting central nervous system development. Most POPs are known aryl hydrocarbon receptor (AhR) ligands and activators of AhR signaling. Therefore, AhR activation has been suggested to cause developmental neurotoxicity (DNT). Objective We studied the effects of AhR ligands on basic processes of brain development in two comparative in vitro systems to determine whether AhR-activation is the underlying mechanism for reported DNT of POPs in humans. Methods We employed neurosphere cultures based on human neural progenitor cells (hNPCs) and wild-type and AhR-deficient mouse NPCs (mNPCs) and studied the effects of different AhR agonists [3-methylcholanthrene (3-MC), benzo(a)pyrene [B(a)P], and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)] and an antagonist [3′-methoxy-4′-nitroflavone (MNF)] on neurosphere development. Moreover, we analyzed expression of AhR and genes involved in AhR signaling. Results In contrast to wild-type mNPCs, hNPCs and AhR-deficient mNPCs were insensitive to AhR agonism or antagonism. Although AhR modulation attenuated wild-type mNPC proliferation and migration, hNPCs and AhR-deficient mNPCs remained unaffected. Results also suggest that species-specific differences resulted from nonfunctional AhR signaling in hNPCs. Conclusion Our findings suggest that in contrast to wild-type mNPCs, hNPCs were protected against polycyclic aromatic hydrocarbon–induced DNT because of an absence of AhR. This difference may contribute to species-specific differences in sensitivity to POPs. PMID:20570779

  10. Avian Influenza A(H5N1) and A(H9N2) Seroprevalence and Risk Factors for Infection Among Egyptians: A Prospective, Controlled Seroepidemiological Study

    PubMed Central

    Gomaa, Mokhtar R.; Kayed, Ahmed S.; Elabd, Mona A.; Zeid, Dina Abu; Zaki, Shaimaa A.; El Rifay, Amira S.; Sherif, Lobna S.; McKenzie, Pamela P.; Webster, Robert G.; Webby, Richard J.; Ali, Mohamed A.; Kayali, Ghazi

    2015-01-01

    Background. A(H5N1) and A(H9N2) avian influenza viruses are enzootic in Egyptian poultry, and most A(H5N1) human cases since 2009 have occurred in Egypt. Our understanding of the epidemiology of avian viruses in humans remains limited. Questions about the frequency of infection, the proportion of infections that are mild or subclinical, and the case-fatality rate remain largely unanswered. Methods. We conducted a 3-year, prospective, controlled, seroepidemiological study that enrolled 750 poultry-exposed and 250 unexposed individuals in Egypt. Results. At baseline, the seroprevalence of anti-A(H5N1) antibodies (titer, ≥80) among exposed individuals was 2% significantly higher than that among the controls (0%). Having chronic lung disease was a significant risk factor for infection. Antibodies against A(H9N2) were not detected at baseline when A(H9N2) was not circulating in poultry. At follow-up, A(H9N2) was detected in poultry, and consequently, the seroprevalence among exposed humans was between 5.6% and 7.5%. Vaccination of poultry, older age, and exposure to ducks were risk factors for A(H9N2) infection. Conclusions. Results of this study indicate that the number of humans infected with avian influenza viruses is much larger than the number of reported confirmed cases. In an area where these viruses are enzootic in the poultry, human exposure to and infection with avian influenza becomes more common. PMID:25355942

  11. Coactivator recruitment of AhR/ARNT1.

    PubMed

    Endler, Alexander; Chen, Li; Shibasaki, Futoshi

    2014-01-01

    A common feature of nuclear receptors (NRs) is the transformation of external cell signals into specific transcriptions of the signal molecule. Signal molecules function as ligands for NRs and, after their uptake, activated NRs form homo- or heterodimers at promoter recognition sequences of the specific genes in the nucleus. Another common feature of NRs is their dependence on coactivators, which bridge the basic transcriptional machinery and other cofactors to the target genes, in order to initiate transcription and to unwind histone-bound DNA for exposing additional promoter recognition sites via their histone acetyltransferase (HAT) function. In this review, we focus on our recent findings related to the recruitment of steroid receptor coactivator 1 (SRC1/NCoA1) by the estrogen receptor-α (ERα) and by the arylhydrocarbon receptor/arylhydrocarbon receptor nuclear translocator 1 (AhR/ARNT1) complex. We also describe the extension of our previously published findings regarding the binding between ARNT1.1 exon16 and SRC1e exon 21, via in silico analyses of androgen receptor (AR) NH2-carboxyl-terminal interactions, the results of which were verified by in vitro experiments. Based on these data, we suggest a newly derived tentative binding site of nuclear coactivator 2/glucocorticoid receptor interacting protein-1/transcriptional intermediary factor 2 (NCOA-2/ GRIP-1/TIF-2) for ARNT1.1 exon 16. Furthermore, results obtained by immunoprecipitation have revealed a second leucine-rich binding site for hARNT1.1 exon 16 in SRC1e exon 21 (LSSTDLL). Finally, we discuss the role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as an endocrine disruptor for estrogen related transcription. PMID:24950180

  12. AHS and CASI Processing for the REFLEX Remote Sensing Campaign: Methods and Results

    NASA Astrophysics Data System (ADS)

    De Miguel, Eduardo; Jiménez, Marcos; Pérez, Irene; de la Cámara, Óscar G.

    2015-12-01

    The airborne spectroradiometers AHS and CASI were used as a source of hyperspectral and thermal remote sensing data during the REFLEX campaign. Data geolocation and a first simple atmospheric correction was performed by INTA in near-real time with a specific on-site setup and distributed to all campaign participants. In this paper we present briefly the AHS and CASI REFLEX flight campaign followed by a detailed description of the methodology used for image processing and finally the results obtained in terms of image quality. As a conclusion, near-real time processing for AHS and CASI level 1 geolocated products was successful as most of CASI level 2 results but further work is needed for achieving accurate AHS level 2 products.

  13. The 50Ah NiH2 cell life test results

    NASA Technical Reports Server (NTRS)

    Jamin, Thierry; Puig, Olivier

    1992-01-01

    Information is given in viewgraph form for the 50 AhNiH2 cell life test results. Information is given on pressure vessel design, electrochemical/stack design, cell electrical characteristics, and cell life test results.

  14. Cloning of a factor required for activity of the Ah (dioxin) receptor

    SciTech Connect

    Hoffman, E.C.; Reyes, H.; Chu, Fongfong; Sander, F.; Conley, L.H.; Brooks, B.A.; Hankinson, O. )

    1991-05-17

    The aryl hydrocarbon (Ah) receptor binds various environmental pollutants, such as polycyclic aromatic hydrocarbons, heterocyclic amines, and polychlorinated aromatic compounds (dioxins, dibenzofurans, and biphenyls), and mediates the carcinogenic effects of these agents. The complementary DNA and part of the gene for an 87-kilodalton human protein that is necessary for Ah receptor function have been cloned. The protein is not the ligand-binding subunit of the receptor but is a factor that is required for the ligand-binding subunit to translocate from the cytosol to the nucleus after binding ligand. The requirement for this factor distinguishes the Ah receptor from the glucocorticoid receptor, to which the Ah receptor has been presumed to be similar. Two portions of the 87-kilodalton protein share sequence similarities with two Drosophila proteins, Per and Sim. Another segment of the protein shows conformity to the consensus sequence for the basic helix-loop-helix motif found in proteins that bind DNA as homodimers or heterodimers.

  15. Activation of AhR-mediated toxicity pathway by emerging pollutants polychlorinated diphenyl sulfides

    EPA Science Inventory

    Polychlorinated diphenyl sulfides (PCDPSs) are a group of environmental pollutants for which limited toxicological information is available. This study tested the hypothesis that PCDPSs could activate the mammalian aryl hydrocarbon receptor (AhR) mediated toxicity pathways. Eight...

  16. The cerebrovascular response to graded Valsalva maneuvers while standing

    PubMed Central

    Perry, Blake G.; Mündel, Toby; Cochrane, Darryl J.; Cotter, James D.; Lucas, Samuel J. E.

    2014-01-01

    Abstract The Valsalva maneuver (VM) produces large and abrupt increases in mean arterial pressure (MAP) at the onset of strain (Phase I), however, hypotension, sufficient to induce syncope, occurs upon VM release (phase III). We examined the effect of VM intensity and duration on middle cerebral artery blood velocity (MCAv) responses. Healthy men (n =10; mean ± SD: 26 ± 4 years) completed 30%, 60%, and 90% of their maximal VM mouth pressure, for 5 and 10 sec (order randomized) while standing. Beat‐to‐beat MCAv and MAP during phase I (peak), at nadir (phase III), and recovery are reported as the change from standing baseline. During phase I, MCAv rose 15 ± 6 cm·s−1 (P <0.001), which was not reliably different between intensities (P =0.11), despite graded increases in MAP (P <0.001; e.g., +12 ± 9 mmHg vs. +35 ± 14 for 5 sec 30% and 90% VM, respectively). During Phase III, the MCAv response was duration‐ (P = 0.045) and intensity dependent (P < 0.001), with the largest decrease observed following the 90% VM (e.g., −19 ± 13 and −15 ± 11 cm·s−1 for 5 and 10 sec VM, respectively) with a concomitant decrease in MAP (P <0.001, −23 ± 11 and −23 ± 9 mmHg). This asymmetric response may be attributable to the differential modulators of MCAv throughout the VM. The mechanical effects of the elevated intrathoracic pressure during phase I may restrain increases in cerebral perfusion via related increases in intracranial pressure; however, during phase III the decrease in MCAv arises from an abrupt hypotension, the extent of which is dependent upon both the duration and intensity of the VM. PMID:24744902

  17. Communicating by Doppler: Detecting Spacecraft Dynamics During Critical Maneuvers

    NASA Technical Reports Server (NTRS)

    Asmar, Sami W.

    2012-01-01

    Communicating information from spacecraft in deep space utilizes sophisticated techniques of modulations onto a microwave signal carrier. Under most conditions, there is a high success rate of sending commands to the spacecraft and receiving science data acquired by on-board instruments along with health and status information. There are conditions, however, where the signal dynamics are too high and/or the received signal-to-noise ratio is below the receiver threshold. Under these conditions, often by design and sometimes as a result of planned or unplanned critical maneuvers, events (e.g., orbit insertion or descent and landing), safe mode, etc., it becomes highly critical but exceedingly challenging to receive information about the health and dynamical behavior of the spacecraft. The Deep Space Network, being a world-class instrument for Radio Science research, developed openloop receivers, called the Radio Science Receiver, designed to capture the raw incoming electromagnetic signals and associated noise for Radio Science experiments; post data capture digital signal processing extracts the signal carrier for scientific analysis. This receiver provides a high level of configuration flexibility and can be optimized for the various types of experiments. In addition to its scientific utility, it proved to be useful, and in some cases critical, for the support of missions during specific scenarios were the link budget is below the threshold of the tracking receiver to maintain lock or the frequency dynamics are faster than the limits of the tracking receiver. In these cases, the signal carrier is often detected only in the open-loop receiver to provide information on the specific behavior of the spacecraft from the carrier dynamics. This paper describes the utility of the system to support mission-critical events for the three cases of Cassini's Saturn orbit insertion, Huygens Titan landing, and Mars rovers landing.

  18. Vortex Ring Extremization for Low Speed Maneuvering of Underwater Vehicles

    NASA Astrophysics Data System (ADS)

    Mohseni, Kamran

    2004-11-01

    Most attempts in underwater locomotion have been focused on propeller thrust generation or recently on flapping locomotion. However, new developments in autonomous and tethered underwater vehicles motivated closer look at the biomimetics of sea animals. To this end, Cephalopoda and jelly fish utilize pulsatile jets and vortex formation for locomotion. To avoid further complications with background flows, we focus on the formation of the leading vortex ring rather than a train of vortices. It is shown that a pinched-off vortex ring characterizes the extremum impulse accumulated by the leading vortex ring in vortex formation process. An appropriate scaling for vortex ring impulse is found and the limiting values of the non-dimensionalized impulses are established. An estimate for the non-dimensional impulses is provided by equating their values from the slug model with their values from a vortex in the Norbury family of vortices. For a vortex ring generator with constant kinetic energy and circulation generation rate, the pinched-off vortex ring has a maximum impulse of I_nd^E ≈ 11 normalized by the circulation and energy. On the other hand, for a vortex ring generator with constant rate of circulation generation at a constant translational velocity, a pinched-off vortex ring produces a minimum impulse of I_nd^Γ ≈ 0.12 normalized by the circulation and translational velocity. Direct numerical simulations of vortex ring formation and vortex ring pinch-off process are performed and the estimated values of the non-dimensionalized impulses are confirmed. These ideas are employed in designing a vortex jet generator for low speed maneuvering of underwater robots. The presented vortex generators are simple and low cost, they consume little valuable payload space, and they have no moving external parts. Experimental data are presented in support of the optimal formation number of 4 for maximum thrust generation.

  19. Orbiter Repair Maneuver Contingency Separation Methods and Analysis

    NASA Technical Reports Server (NTRS)

    Machula, Michael

    2005-01-01

    Repairing damaged thermal protection system tile requires the Space Shuttle to be oriented such that repair platform access from the International Space Station (ISS) is possible. To do this, the Space Shuttle uses the Orbiter Repair Maneuver (ORM), which utilizes the Shuttle Remote Manipulator System (SRMS) to rotate the Space Shuttle in relation to the ISS, for extended periods of time. These positions cause difficulties and challenges to performing a safe separation (no collision or thruster plume damage to sensitive ISS structures) should an inadvertent release occur or a contingency procedure require it. To help protect for an SRMS failure or other failures, a method for separating without collision and the ability to redock to ISS from the ORM configuration was needed. The contingency ORM separation solution elegantly takes advantage of orbital mechanics between ISS and the separating Space Shuttle. By pitching the ISS down approximately 45 degrees, in a majority of the ORM repair positions, the altitude difference between the ISS and Space Shuttle center of gravity is maximized. This altitude difference results in different orbital energies (orbital periods) causing objects to separate from each other without requiring translational firings. Using this method, a safe contingency ORM separation is made possible in many odd positions even though some separation positions point high powered thrusters directly at fragile ISS and Soyuz solar arrays. Documented in this paper are the development simulations and procedures of the contingency ORM separation and the challenges encountered with large constraints to work around. Lastly, a method of returning to redock with the ISS to pick up the stranded crew members (or transfer the final crew members) is explained as well as the thruster and ISS loads analysis.

  20. FIXING JEJUNAL MANEUVER TO PREVENT PETERSEN HERNIA IN GASTRIC BYPASS

    PubMed Central

    MURAD-JUNIOR, Abdon José; SCHEIBE, Christian Lamar; CAMPELO, Giuliano Peixoto; de LIMA, Roclides Castro; MURAD, Lucianne Maria Moraes Rêgo Pereira; dos SANTOS, Eduardo Pachu Raia; RAMOS, Almino Cardoso; VALADÃO, José Aparecido

    2015-01-01

    Background : Among Roux-en-Y gastric bypass complications is the occurrence of intestinal obstruction by the appearance of internal hernias, which may occur in Petersen space or the opening in mesenteric enteroenteroanastomosis. Aim : To evaluate the efficiency and safety in performing a fixing jejunal maneuver in the transverse mesocolon to prevent internal hernia formation in Petersen space. Method : Two surgical points between the jejunum and the transverse mesocolon, being 5 cm and 10 cm from duodenojejunal angle are made. In all patients was left Petersen space open and closing the opening of the mesenteric enteroenteroanastomosis. Results : Among 52 operated patients, 35 were women (67.3%). The age ranged 18-63 years, mean 39.2 years. BMI ranged from 35 to 56 kg/m2 (mean 40.5 kg/m2). Mean follow-up was 15.1 months (12-18 months). The operative time ranged from 68-138 min. There were no intraoperative complications, and there were no major postoperative complications and no reoperations. The hospital stay ranged from 2-3 days. During the follow-up, no one patient developed suspect clinical presentation of internal hernia. Follow-up in nine patients (17.3%) showed asymptomatic cholelithiasis and underwent elective laparoscopic cholecystectomy. During these procedures were verified the Petersen space and jejunal fixation. In all nine, there was no herniation of the jejunum to the right side in Petersen space. Conclusion : The fixation of the first part of the jejunum to left side of the transverse mesocolon is safe and effective to prevent internal Petersen hernia in RYGB postoperatively in the short and medium term. It may be interesting alternative to closing the Petersen space. PMID:26537279