WorldWideScience

Sample records for beta maneuvering reentry

  1. Control of a high beta maneuvering reentry vehicle using dynamic inversion.

    Energy Technology Data Exchange (ETDEWEB)

    Watts, Alfred Chapman

    2005-05-01

    The design of flight control systems for high performance maneuvering reentry vehicles presents a significant challenge to the control systems designer. These vehicles typically have a much higher ballistic coefficient than crewed vehicles like as the Space Shuttle or proposed crew return vehicles such as the X-38. Moreover, the missions of high performance vehicles usually require a steeper reentry flight path angle, followed by a pull-out into level flight. These vehicles then must transit the entire atmosphere and robustly perform the maneuvers required for the mission. The vehicles must also be flown with small static margins in order to perform the required maneuvers, which can result in highly nonlinear aerodynamic characteristics that frequently transition from being aerodynamically stable to unstable as angle of attack increases. The control system design technique of dynamic inversion has been applied successfully to both high performance aircraft and low beta reentry vehicles. The objective of this study was to explore the application of this technique to high performance maneuvering reentry vehicles, including the basic derivation of the dynamic inversion technique, followed by the extension of that technique to the use of tabular trim aerodynamic models in the controller. The dynamic inversion equations are developed for high performance vehicles and augmented to allow the selection of a desired response for the control system. A six degree of freedom simulation is used to evaluate the performance of the dynamic inversion approach, and results for both nominal and off nominal aerodynamic characteristics are presented.

  2. Real Time Mid-course Maneuver and Guidance of a Generic Reentry Vehicle

    Directory of Open Access Journals (Sweden)

    Avinash Chander

    2013-07-01

    Full Text Available The aim of any mission is to accomplish the final objective with desired accuracy and the same is valid for a generic launch vehicle. In many missions it is necessary to execute mid-course maneuvers with an intentional diversion trajectory to create a counter measure or to avoid certain specific known geographical locations. The current work elaborates a novel and practically implementable mid-course maneuver and an ascent phase guidance of a reentry vehicle executing an in-flight determined mid-course maneuver (trajectory reshaping without compromising the accuracy of the final achieved target position. The robustness of the algorithm is validated with 6DoF simulation results by considering the dispersion of the burnout state vector conditions which arises due to variations in thrust profile, aerodynamics characteristics of the vehicle, atmosphere, etc.Defence Science Journal, 2013, 63(4, pp.346-354, DOI:http://dx.doi.org/10.14429/dsj.63.4207

  3. Reentry response of the light weight radioisotope heater unit resulting from a Venus-Earth-Earth Gravity Assist maneuver accident

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, J.C.

    1988-10-01

    Reentry analyses consisting of ablation response, thermal response and thermal stress response have been conducted on the Light Weight Radioisotope Heater Unit for Galileo/VEEGA reentry conditions. Sequential ablation analyses of the LWRHU aeroshell, the fuel clad, and the fuel pellet have been conducted in reentry regimes where the aeroshell has been deemed to fail. The failure criterion for ablation is assumed to be recession corresponding to 50% of the wall thickness (the design criterion recommended in the DOE Overall Safety Manual). Although the analyses have been carried far beyond this limit (as presented and discussed herein), JHU/APL endorses the position that failure may occur at the time that this recession is achieved or at lower altitudes within the heat pulse considering the uncertainties in the aerodynamic, thermodynamic, and thermo-structural analyses and modeling. These uncertainties result mainly because of the high energies involved in the VEEGA reentries compared to orbital decay reentries. Risk evaluations should consider the fact that for shallow flight paths the unit may disassemble at high-altitude as a result of ablation or may remain intact until it impacts with a clad that had been molten. 80 refs., 46 figs., 16 tabs.

  4. Reentry response of the lightweight radioisotope heater unit resulting from a Cassini Venus-Venus-Earth-Jupiter gravity assist maneuver accident

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    Reentry analyses consisting of ablation response, thermal response and thermal stress response have been conducted on the Lightweight Radioisotope Heater Unit (LWRHU) for Cassini/Venus-Venus-Earth-Jupiter-Gravity-Assist (VVEJGA) reentry conditions. Sequential ablation analyses of the LWRHU aeroshell, and the fuel pellet have been conducted in reentry regimes where the aeroshell has been deemed to fail. The failure criterion for ablation is generally assumed to be recession corresponding to 75% and 100% of the wall thickness. The 75% recession failure criteria allows for uncertainties that result mainly because of the high energies involved in the VVEJGA reentries compared to orbital decay reentries. Risk evaluations should consider the fact that for shallow flight paths the unit may disassemble at high-altitude as a result of ablation or may remain intact with a clad that had been molten. Within the limitations of the methodologies and assumptions of the analyses, the results indicate that: (1) For a side-on stable LWRHU reentry, aeroshell ablation failures occur for all reentry angles. (2)For a side-on spinning LWRHU reentry, aeroshell ablation failures are minimal. (3) For the tumbling LWRHU reentry, the aeroshell survives for most angles. (4) For the thermostructural analyses, using both a 1% and 5% allowable strain, all reentry angles and orientations examined resulted in small localized failures, but aeroshell breach is not predicted for any case. The analyses included in this report concentrate on VVEJGA reentry scenarios. Analyses reported previously have demonstrated that the LWRHU has adequate design margin to survive reentry from orbital decay scenarios and most injection scenarios at speeds up to escape speeds. The exception is a narrow range of flight path angles that produce multiple skip trajectories which may have excessive ablation.

  5. Reentry Shock

    Institute of Scientific and Technical Information of China (English)

    Dorine; Houston

    1998-01-01

    Dear Xiao Lan, You remember the pain of culture and reentry shock; humor me please; let mereview the facts for the sake of the students you are sending here in greater numbers.Culture shock is the emotional pain that people experience when they visit a newcountry and find customs, experiences, smells, and non-verbal communication stylesto be different from their own country.

  6. Epley maneuver

    Science.gov (United States)

    ... Canalith-Repositioning Maneuvers; CRP; Benign positional vertigo-Epley; Benign paroxysmal positional vertigo-Epley; BPPV-Epley ... Bronston LJ, Cass S, et al. Clinical practice guideline: Benign ... vertigo. Otolaryngology: Head and Neck Surgery . 2008;139(5 ...

  7. Heimlich maneuver on self

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001983.htm Heimlich maneuver on self To use the sharing features on ... are choking on something, you can perform the Heimlich maneuver on yourself. Follow these steps: Make a fist ...

  8. Choking (Heimlich Maneuver)

    Science.gov (United States)

    ... A-Z Share this! Home » Emergency 101 Choking (Heimlich Maneuver) ACEP recommends that the Heimlich Maneuver be employed only when a person is choking ... death. Avoid using excessive force in employing the Heimlich Maneuver to avoid injury to the ribs or internal ...

  9. The prospect of responsive spacecraft using aeroassisted, trans-atmospheric maneuvers

    Science.gov (United States)

    Bettinger, Robert A.

    Comprised of exo- and trans-atmospheric trajectory segments, atmospheric re-entry represents a complex dynamical event which traditionally signals the mission end-of-life for low-Earth orbit (LEO) spacecraft, both manned and unmanned. Transcending this paradigm, atmospheric re-entry can be employed as a means of operational maneuver whereby the aerodynamic forces of the upper atmosphere can be exploited to create an aeroassisted maneuver. Utilizing a notional trans-atmospheric, lifting re-entry vehicle with L/D=6, the first phase of research demonstrates the terrestrial reachability potential for skip entry aeroassisted maneuvers. By overflying a geographically diverse set of sample ground targets, comparative analysis indicates a significant savings in DeltaV expenditure for skip entry compared with planar phasing and simple plane change exo-atmospheric maneuvers. In the second phase, the Design of Experiments method of orthogonal arrays provides optimal vehicle and skip entry trajectory designs by employing main effects and Pareto front analysis. Depending on the chosen re-circularization altitude, the coupled optimal design can achieve an inclination change of 19.91 deg with 50-85% less DeltaV than a simple plane change. Finally, the third phase introduces the descent-boost aeroassisted maneuver as an alternative to combined Hohmann and bi-elliptic transfers in order to perform LEO injection. Compared with bi-elliptic transfers, simulations demonstrate that a lifting re-entry vehicle with L/D=6 performing a descent-boost maneuver requires 6-12% less DeltaV for injection into orbits lower than 650 km. In addition, the third phase also introduces the "Maneuver Performance Number" as a dimensionless means of comparative effectiveness analysis for both exo- and trans-atmospheric maneuvers.

  10. Maneuver Automation Software

    Science.gov (United States)

    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.

  11. Small Probe Reentry System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Global Aerospace Corporation (GAC), and its research partner, Cal Poly San Luis Obispo (CPSLO), will develop an integrated Small Probe Reentry System (SPRS) for low...

  12. 75 FR 75621 - Office of Commercial Space Transportation; Waiver of Autonomous Reentry Restriction for a Reentry...

    Science.gov (United States)

    2010-12-06

    ... its reentry vehicle, the Dragon Spacecraft (Dragon), by command. The first petition is unnecessary... waiving the requirement for SpaceX ground operators to initiate Dragon's reentry to Earth is in the public... Transportation (AST) for the reentry of Dragon, a reentry vehicle, to be launched on Falcon 9 flight 002....

  13. Re-entry flight clearance

    NARCIS (Netherlands)

    Juliana, S.

    2006-01-01

    The objective of the research was to identify and evaluate promising mathematical techniques for re-entry flight clearance. To fulfil this objective, two mathematical methods were investigated and developed: μ analysis for linear models and interval analysis for both linear and non-linear model

  14. Pico Reentry Probes: Affordable Options for Reentry Measurements and Testing

    Science.gov (United States)

    Ailor, William H.; Kapoor, Vinod B.; Allen, Gay A., Jr.; Venkatapathy, Ethiraj; Arnold, James O.; Rasky, Daniel J.

    2005-01-01

    It is generally very costly to perform in-space and atmospheric entry experiments. This paper presents a new platform - the Pico Reentry Probe (PREP) - that we believe will make targeted flight-tests and planetary atmospheric probe science missions considerably more affordable. Small, lightweight, self-contained, it is designed as a "launch and forget" system, suitable for experiments that require no ongoing communication with the ground. It contains a data recorder, battery, transmitter, and user-customized instrumentation. Data recorded during reentry or space operations is returned at end-of-mission via transmission to Iridium satellites (in the case of earth-based operations) or a similar orbiting communication system for planetary missions. This paper discusses possible applications of this concept for Earth and Martian atmospheric entry science. Two well-known heritage aerodynamic shapes are considered as candidates for PREP: the shape developed for the Planetary Atmospheric Experiment Test (PAET) and that for the Deep Space II Mars Probe.

  15. Reusable Reentry Satellite (RRS) system design study

    Science.gov (United States)

    1991-01-01

    The Reusable Reentry Satellite (RRS) is intended to provide investigators in several biological disciplines with a relatively inexpensive method to access space for up to 60 days with eventual recovery on Earth. The RRS will permit totally intact, relatively soft, recovery of the vehicle, system refurbishment, and reflight with new and varied payloads. The RRS is to be capable of three reflights per year over a 10-year program lifetime. The RRS vehicle will have a large and readily accessible volume near the vehicle center of gravity for the Payload Module (PM) containing the experiment hardware. The vehicle is configured to permit the experimenter late access to the PM prior to launch and rapid access following recovery. The RRS will operate in one of two modes: (1) as a free-flying spacecraft in orbit, and will be allowed to drift in attitude to provide an acceleration environment of less than 10(exp -5) g. the acceleration environment during orbital trim maneuvers will be less than 10(exp -3) g; and (2) as an artificial gravity system which spins at controlled rates to provide an artificial gravity of up to 1.5 Earth g. The RRS system will be designed to be rugged, easily maintained, and economically refurbishable for the next flight. Some systems may be designed to be replaced rather than refurbished, if cost effective and capable of meeting the specified turnaround time. The minimum time between recovery and reflight will be approximately 60 days. The PMs will be designed to be relatively autonomous, with experiments that require few commands and limited telemetry. Mass data storage will be accommodated in the PM. The hardware development and implementation phase is currently expected to start in 1991 with a first launch in late 1993.

  16. Nonlinear Maneuver Autopilot

    Science.gov (United States)

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

    1992-01-01

    Trajectory-control laws based on singular-perturbation theory and nonlinear dynamical modeling. Nonlinear maneuver autopilot commands flight-test trajectories of F-15 airplane. Underlying theory of controller enables separation of variables processed in fast and slow control loops, reducing amount of computation required.

  17. Electrophysiologic and antiarrhythmic effects of intravenous bisoprolol in atrioventricular nodal reentry tachycardia

    NARCIS (Netherlands)

    vandeVen, LLM; Crijns, HJGM; deMuinck, ED; VanGelder, IC; VanWijk, LM; Lie, KI

    1996-01-01

    Beta-blockade may be useful in the termination and prevention of atrioventricular nodal reentry tachycardia (AVNRT), An electrophysiologic study was performed in 9 patients (4 men and 5 women; mean +/- SD age, 56 +/- 16 years) with documented AVNRT before and after the intravenous administration of

  18. IXV re-entry demonstrator: Mission overview, system challenges and flight reward

    Science.gov (United States)

    Angelini, Roberto; Denaro, Angelo

    2016-07-01

    The Intermediate eXperimental Vehicle (IXV) is an advanced re-entry demonstrator vehicle aimed to perform in-flight experimentation of atmospheric re-entry enabling systems and technologies. The IXV integrates key technologies at the system level, with significant advancements on Europe's previous flying test-beds. The project builds on previous achievements at system and technology levels, and provides a unique and concrete way of establishing and consolidating Europe's autonomous position in the strategic field of atmospheric re-entry. The IXV mission and system objectives are the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled reentry system, integrating critical re-entry technologies at system level. Among such critical technologies of interest, special attention is paid to aerodynamic and aerothermodynamics experimentation, including advanced instrumentation for aerothermodynamics phenomena investigations, thermal protections and hot-structures, guidance, navigation and flight control through combined jets and aerodynamic surfaces (i.e. flaps), in particular focusing on the technologies integration at system level for flight. Following the extensive detailed design, manufacturing, qualification, integration and testing of the flight segment and ground segment elements, IXV has performed a full successful flight on February 11th 2015. After the launch with the VEGA launcher form the CSG spaceport in French Guyana, IXV has performed a full nominal mission ending with a successful splashdown in the Pacific Ocean. During Flight Phase, the IXV space and ground segments worked perfectly, implementing the whole flight program in line with the commanded maneuvers and trajectory prediction, performing an overall flight of 34.400 km including 7.600 km with hot atmospheric re-entry in automatic guidance, concluding with successful precision landing at a distance of ~1

  19. Phase 2 reentry in man

    DEFF Research Database (Denmark)

    Thomsen, P.E.B.; Jørgensen, R.M.; Kanters, J.K.;

    2005-01-01

    mu V, range 0-1,700) and T-wave changes in the sinus beat prior to ventricular ectopy. In addition, J-point elevation was demonstrated in several cases. In total, significant changes were demonstrated in 15 of the 18 patients studied (83%). CONCLUSION J-point elevation, ST-elevation, and T......-wave changes documented in the last sinus beat prior to ventricular extrasystoles are in agreement with phase 2 reentry, suggesting that this may be the responsible mechanism for ventricular extrasystoles and ventricular tachycardia/fibrillation. The phenomenon has been demonstrated in only animal experiments...

  20. Structural Dynamics of Maneuvering Aircraft.

    Science.gov (United States)

    1987-09-01

    AD-RI92 376 STRUCTURAL DYNAMICS OF MANEUVERING RIRCRAFT(U) CONRAD I TECHNOLOGIES INC KING OF PRUSSIA PR M M REDDI SEP 97 CTI-8601 NRDC-88014-69...REPORT NO. NADC-8014-60 STRUCTURAL DYNAMICS OF MANEUVERING AIRCRAFT M. Mahadeva Reddi .4 Conrad Technologies, Inc. 650 S. Henderson Rd. D T IQ King of...NO A0 CCESSION NO. R02303001 107601 11. TITLE (Include Security Classfication) (u) STRUCTURAL DYNAMICS OF MANEUVERING AIRCRAFT 12. PERSONAL AUTHORS) M

  1. Ruptured jejunum following Heimlich maneuver.

    Science.gov (United States)

    Razaboni, R M; Brathwaite, C E; Dwyer, W A

    1986-01-01

    The Heimlich maneuver, over time, has proved to be a useful resuscitative procedure in the management of cases with airway occlusion secondary to foreign body. Medical treatments, however, can have side effects, and this maneuver is no exception. A previously unreported complication is presented, that of jejunal rupture. The proper application of the maneuver minimizes the number of side effects; however, since they do occur, it is suggested that all persons subject to this maneuver be subsequently evaluated by a physician as soon after the incident as is practicable.

  2. Pneumomediastinum following the Heimlich maneuver.

    Science.gov (United States)

    Agia, G A; Hurst, D J

    1979-11-01

    The Heimlich maneuver appears to be a widely accepted technique advocated as a means of clearing an obstructed airway. Reports of complications have been few. We report a case of pneumomediastinum that occurred following the generation of increased pulmonary pressures during performance of the Heimlich maneuver.

  3. Analysis of the inadvertent reentry of the Cassini Spacecraft{close_quote}s Radioisotope Thermoelectric Generators

    Energy Technology Data Exchange (ETDEWEB)

    Tobery, E.W. [Lockheed Martin Astronautics, King of Prussia, Pennsylvania 19406 (United States); Bhutta, B.A. [AeroTechnologies, Inc, Yorktown, Virginia 23692 (United States)] [Analysis of the inadvertent reentry of the Cassini Spacecrafts Radioisotope Thermoelectric Generators

    1999-01-01

    A rigorous multi-discipline approach has been developed to compute the aero/thermal/structural response of the Cassini Spacecraft{close_quote}s G{underscore}eneral P{underscore}urpose H{underscore}eat S{underscore}ource (GPHS) modules in the unlikely event of accidental reentry of the spacecraft during its Earth gravity-assist maneuver. A new r{underscore}eacting, a{underscore}blating, c{underscore}hemical e{underscore}quilibrium/nonequilibrium with r{underscore}adiation (RACER) full Navier-Stokes code is applied, along with an in-depth, transient-heating code, a nonlinear structural analysis code, and a six-degree-of-freedom flight-dynamics code. Attention is focused on the GPHS modules that would breakaway from the R{underscore}adioisotope T{underscore}hermoelectric G{underscore}enerators (RTGs) at high altitude. In addition, detailed analyses are performed to determine the survival/failure of the Graphite Impact Shells that would be released if the GPHS fails. The reentry velocity of the GPHS module (20 km/sec) is higher than any previously analyzed Earth reentry trajectory. {copyright} {ital 1999 American Institute of Physics.}

  4. 75 FR 75619 - Waiver of Acceptable Mission Risk Restriction for Reentry and a Reentry Vehicle

    Science.gov (United States)

    2010-12-06

    ... Space Transportation (AST) requesting two waivers with respect to a reentry license for Dragon, a... ) for that mission exceeds 30 x 10 -6 . \\1\\ Even though Dragon is a reentry vehicle and not a reusable..., named Dragon, into orbit. Once Dragon is in orbit, it will be subjected to a ground-implemented...

  5. 14 CFR 25.1507 - Maneuvering speed.

    Science.gov (United States)

    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)....

  6. Spacecraft Re-Entry Impact Point Targeting Using Aerodynamic Drag

    Science.gov (United States)

    Omar, Sanny R.; Bevilacqua, Riccardo

    2017-01-01

    The ability to re-enter the atmosphere at a desired location is important for spacecraft containing components that may survive re-entry. While impact point targeting has traditionally been initiated through impulsive burns with chemical thrusters on large vehicles such as the Space Shuttle, and the Soyuz and Apollo capsules, many small spacecraft do not host thrusters and require an alternative means of impact point targeting to ensure that falling debris do not cause harm to persons or property. This paper discusses the use of solely aerodynamic drag force to perform this targeting. It is shown that by deploying and retracting a drag device to vary the ballistic coefficient of the spacecraft, any desired longitude and latitude on the ground can be targeted provided that the maneuvering begins early enough and the latitude is less than the inclination of the orbit. An analytical solution based on perturbations from a numerically propagated trajectory is developed to map the initial state and ballistic coefficient profile of a spacecraft to its impact point. This allows the ballistic coefficient profile necessary to reach a given target point to be rapidly calculated, making it feasible to generate the guidance for the decay trajectory onboard the spacecraft. The ability to target an impact point using aerodynamic drag will enhance the capabilities of small spacecraft and will enable larger space vehicles containing thrusters to save fuel by more effectively leveraging the available aerodynamic drag.

  7. Research on Estimation of Reentry Trajectory Based on Dynamical Model%基于动力学模型的再入弹道估计方法研究

    Institute of Scientific and Technical Information of China (English)

    江晓东; 谢京稳; 郭军海

    2011-01-01

    It is extremely significant to track reentry spacecraft and get precise estimation of their trajectory in the reentry phase. During atmospheric reentry phase, the locus of spacecraft can be described approximately by a dynamical model. The paper first uses UKF to estimate the trajectory of reentry targets and then compares the result with solution of 3RR method. The simulation result shows that UKF based on the dynamical model effectively improves trajectory estimation precision of reentry targets for a ballistic reentry vehicle, but only improves appreciably the estimation precision of maneuvering reentry vehicles.%对再入飞行器进行跟踪,获取目标弹道的精确估计具有十分重要的现实意义.飞行器在再入段的弹道可用较为精确的动力学模型描述,并利用UKF对目标的弹道进行估计,与3RR几何法解算结果进行比对.仿真结果表明,对于弹道式再入飞行器,基于BRV-Exp模型的弹道估计精度比3RR法具有明显改善;对于机动式再入飞行器,基于MRV-Wiener模型的估计精度只是略微优于3RR法的弹道估计精度.

  8. Aerothermodynamic Analysis of a Reentry Brazilian Satellite

    CERN Document Server

    Santos, Wilson F N

    2012-01-01

    This work deals with a computational investigation on the small ballistic reentry Brazilian vehicle SARA (acronyms for SAt\\'elite de Reentrada Atmosf\\'erica). Hypersonic flows over the vehicle SARA at zero-degree angle of attack in a chemical equilibrium and thermal non-equilibrium are modeled by the Direct Simulation Monte Carlo (DSMC) method, which has become the main technique for studying complex multidimensional rarefied flows, and that properly accounts for the non-equilibrium aspects of the flows. The emphasis of this paper is to examine the behavior of the primary properties during the high altitude portion of SARA reentry. In this way, velocity, density, pressure and temperature field are investigated for altitudes of 100, 95, 90, 85 and 80 km. In addition, comparisons based on geometry are made between axisymmetric and planar two-dimensional configurations. Some significant differences between these configurations were noted on the flowfield structure in the reentry trajectory. The analysis showed t...

  9. A Survey of Uncontrolled Satellite reentry and Impact Prediction

    Science.gov (United States)

    1993-09-23

    18. Klinkrad , H.H., "Long-term Analytical Orbit Decay and Reentry Prediction," ESA SP-246, Proceedings Workshop on Re-entry of Space Debris, Darmstadt...SP-345), The Reentry qffSalyvz- 7/Kosmos- 6.86, Proceedings International Workshop ESOC, Darmstadt (D), Apr. 9, J991, pp. 9-15. 247 94. Klinkrad , H

  10. 40 CFR 161.390 - Reentry protection data requirements.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Reentry protection data requirements... § 161.390 Reentry protection data requirements. (a) Table. Sections 161.100 through 161.102 describe how to use this table to determine the reentry protection data requirements and the substance to...

  11. YPF uses horizontal reentry to aid thin bed production

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, M.R.; Leiro, F.A.; Sesano, G.S. [Yacimientos Petroliferos Fiscales, La Paz (Bolivia); Hill, D.

    1997-01-01

    Reentry and horizontal drilling/completion techniques have proven themselves useful in exploiting thin beds. A pilot horizontal reentry contracted by Yacimiento Petroliferos Fiscales (YPF) for a marginal well in its Lomita Sur field resulted in decreased water coning and production rates four times greater than expected. Further horizontal reentries in this thin-bed field are planned.

  12. Estimating Characteristics of a Maneuvering Reentry Vehicle Observed by Multiple Sensors

    Science.gov (United States)

    2010-03-01

    slon = sin(sen_lla(2)); clon = cos(sen_lla(2)); % sin & cos of ECI->ECEF angle st = sin(earth.AngVel * obs_time); ct...azimuth partials 94 numer_Az = -slon*(ct*x+st*y-sen_ecf(1))+ clon *(-st*x+ct*y- sen_ecf(2)); denom_Az = -slat... clon *(ct*x+st*y-sen_ecf(1))-slat*slon*(- st*x+ct*y-sen_ecf(2))+clat*(z-sen_ecf(3)); dAz_base = 1/(1 + (numer_Az/denom_Az)^2); % derivative of

  13. Post-Flight Trajectory Reconstruction of a Maneuvering Reentry Vehicle from Radar Measurements

    Science.gov (United States)

    1982-12-01

    8217. *’.÷ ...... . Runge-Kutta method modified by Nystroih to handle the second " -"order equation. Kreyszig (Ref 21) calls this the Runge- Kutta...Prediction Theory," J. Basic Eng Vol 83, 1961, pp 95-108. 21. Kreyszig , E. Advanced Engineering Mathematics (FourthI ~. Edition), John Wiley and Sons

  14. Dynamics of Voluntary Cough Maneuvers

    Science.gov (United States)

    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.

  15. Prisoner Reentry Programming: Who Recidivates and when?

    Science.gov (United States)

    Severson, Margaret E.; Bruns, Kimberly; Veeh, Christopher; Lee, Jaehoon

    2011-01-01

    This article provides the results of a multi-year evaluation of one state's prison reentry program and its impact on the success of offender participants as measured by certain recidivism outcomes, defined here as yielding a positive urinalysis, returning to prison, and having a new conviction. Using propensity score matching, the recidivism…

  16. School Reentry Following Traumatic Brain Injury

    Science.gov (United States)

    Deidrick, Kathleen K. M.; Farmer, Janet E.

    2005-01-01

    Successful school reentry following traumatic brain injury (TBI) is critical to recovery. Physical, cognitive, behavioral, academic, and social problems can affect a child's school performance after a TBI. However, early intervention has the potential to improve child academic outcomes and promote effective coping with any persistent changes in…

  17. Space Debris Reentry Analysis Methods and Tools

    Institute of Scientific and Technical Information of China (English)

    WU Ziniu; HU Ruifeng; QU Xi; WANG Xiang; WU Zhe

    2011-01-01

    The reentry of uncontrolled spacecraft may be broken into many pieces of debris at an altitude in the range of 75-85 km.The surviving fragments could pose great hazard and risk to ground and people.In recent years,methods and tools for predicting and analyzing debris reentry and ground risk assessment have been studied and developed in National Aeronautics and Space Administration(NASA),European Space Agency(ESA) and other organizations,including the group of the present authors.This paper reviews the current progress on this topic of debris reentry briefly.We outline the Monte Carlo method for uncertainty analysis,breakup prediction,and parameters affecting survivability of debris.The existing analysis tools can be classified into two categories,i.e.the object-oriented and the spacecraft-oriented methods,the latter being more accurate than the first one.The past object-oriented tools include objects of only simple shapes.For more realistic simulation,here we present an object-oriented tool debris reentry and ablation prediction system(DRAPS) developed by the present authors,which introduces new object shapes to 15 types,as well as 51 predefined motions and relevant aerodynamic and aerothermal models.The aerodynamic and aerothermal models in DRAPS are validated using direct simulation Monte Carlo(DSMC) method.

  18. Career Indecision in Reentry and Undergraduate Women.

    Science.gov (United States)

    Slaney, Fiona MacKinnon

    1986-01-01

    Examined career indecision in 300 reentry and undergraduate women. Results indicated that there were no differences in career indecision in undergraduate women in any of the age groups 17 to 22 years, 30 to 34 years, or 40 to 44 years. (Author/BL)

  19. Progress in reentry trajectory planning for hypersonic vehicle

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhao; Rui Zhou; Xuelian Jin

    2014-01-01

    The reentry trajectory planning for hypersonic vehicles is critical and chal enging in the presence of numerous nonlinear equations of motion and path constraints, as wel as guaranteed satisfaction of accuracy in meeting al the specified boundary con-ditions. In the last ten years, many researchers have investigated various strategies to generate a feasible or optimal constrained reentry trajectory for hypersonic vehicles. This paper briefly re-views the new research efforts to promote the capability of reentry trajectory planning. The progress of the onboard reentry trajectory planning, reentry trajectory optimization, and landing footprint is summarized. The main chal enges of reentry trajectory planning for hypersonic vehicles are analyzed, focusing on the rapid reentry trajectory optimization, complex geographic constraints, and coop-erative strategies.

  20. Operational Maneuver: Function or Fiction?

    Science.gov (United States)

    2007-11-02

    the premise that this would never happen, so why plan for it. That is just the point. Operational art planning should not leave any stone unturned . The... unturned during operational art planning and execution. The maneuver apex theory can be applied to the Air Force operating environment, however, operational

  1. 33 CFR 84.23 - Maneuvering light.

    Science.gov (United States)

    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...

  2. Ground Target Overflight and Orbital Maneuvering via Atmospheric Maneuvers

    Science.gov (United States)

    2014-03-27

    al., 2002:228-230). Prior to the commencement of any research into aeroassisted maneuvers, a firm foundation in the understanding of atmospheric...cosine term is used for prograde orbits while the negative term is used for retrograde orbits. The r(1), r(2), and r(3) terms rerpresent the 1st... retrograde ) only target longitude crossings which occur in the same hemisphere as the 44 target are possible to overfly without changing the inclination

  3. ENTREPRENEURIAL EXIT AND REENTRY: AN EXPLORATORY STUDY OF TURKISH ENTREPRENEURS

    OpenAIRE

    2010-01-01

    This study attempts to develop a better understanding in an emerging economy of the exit and reentry processes of entrepreneurs. Twelve case studies were conducted in Turkey with entrepreneurs who, following entrepreneurial exit, re-entered with new ventures. Human and social capital perspectives are used to gain insights into the reentry process. The study indicates that reasons for and modes of exit influence the entrepreneur's decisions surrounding reentry. Results further reveal that expe...

  4. Intelligent Prediction of Ship Maneuvering

    Directory of Open Access Journals (Sweden)

    Miroslaw Lacki

    2016-09-01

    Full Text Available In this paper the author presents an idea of the intelligent ship maneuvering prediction system with the usage of neuroevolution. This may be also be seen as the ship handling system that simulates a learning process of an autonomous control unit, created with artificial neural network. The control unit observes input signals and calculates the values of required parameters of the vessel maneuvering in confined waters. In neuroevolution such units are treated as individuals in population of artificial neural networks, which through environmental sensing and evolutionary algorithms learn to perform given task efficiently. The main task of the system is to learn continuously and predict the values of a navigational parameters of the vessel after certain amount of time, regarding an influence of its environment. The result of a prediction may occur as a warning to navigator to aware him about incoming threat.

  5. Reentry Works: The Implementation and Effectiveness of a Serious and Violent Offender Reentry Initiative

    Science.gov (United States)

    Bouffard, Jeffrey A.; Bergeron, Lindsey E.

    2006-01-01

    Spurred by large increases in prison populations and other recent sentencing and correctional trends, the federal government has supported the development and implementation of Serious and Violent Offender Reentry Initiatives (SVORI) nationwide. While existing research demonstrates the effectiveness of the separate components of these programs…

  6. Automated Re-Entry System using FNPEG

    Science.gov (United States)

    Johnson, Wyatt R.; Lu, Ping; Stachowiak, Susan J.

    2017-01-01

    This paper discusses the implementation and simulated performance of the FNPEG (Fully Numerical Predictor-corrector Entry Guidance) algorithm into GNC FSW (Guidance, Navigation, and Control Flight Software) for use in an autonomous re-entry vehicle. A few modifications to FNPEG are discussed that result in computational savings -- a change to the state propagator, and a modification to cross-range lateral logic. Finally, some Monte Carlo results are presented using a representative vehicle in both a high-fidelity 6-DOF (degree-of-freedom) sim as well as in a 3-DOF sim for independent validation.

  7. Gender Differences and Offender Reentry: A Review of the Literature

    Science.gov (United States)

    Spjeldnes, Solveig; Goodkind, Sara

    2009-01-01

    Historically, men have been incarcerated at rates far greater than women. As a result, reentry and reintegration programs have focused mainly on men's needs. The Second Chance Act of 2007 authorized funding for offender reentry programs and research on special populations--including about women and parents acknowledging the importance of…

  8. Direct lateral maneuvers in hawkmoths

    Directory of Open Access Journals (Sweden)

    Jeremy S. M. Greeter

    2016-01-01

    Full Text Available 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.

  9. A Novel Method for Satellite Maneuver Prediction

    Science.gov (United States)

    Shabarekh, C.; Kent-Bryant, J.; Keselman, G.; Mitidis, A.

    2016-09-01

    A space operations tradecraft consisting of detect-track-characterize-catalog is insufficient for maintaining Space Situational Awareness (SSA) as space becomes increasingly congested and contested. In this paper, we apply analytical methodology from the Geospatial-Intelligence (GEOINT) community to a key challenge in SSA: predicting where and when a satellite may maneuver in the future. We developed a machine learning approach to probabilistically characterize Patterns of Life (PoL) for geosynchronous (GEO) satellites. PoL are repeatable, predictable behaviors that an object exhibits within a context and is driven by spatio-temporal, relational, environmental and physical constraints. An example of PoL are station-keeping maneuvers in GEO which become generally predictable as the satellite re-positions itself to account for orbital perturbations. In an earlier publication, we demonstrated the ability to probabilistically predict maneuvers of the Galaxy 15 (NORAD ID: 28884) satellite with high confidence eight days in advance of the actual maneuver. Additionally, we were able to detect deviations from expected PoL within hours of the predicted maneuver [6]. This was done with a custom unsupervised machine learning algorithm, the Interval Similarity Model (ISM), which learns repeating intervals of maneuver patterns from unlabeled historical observations and then predicts future maneuvers. In this paper, we introduce a supervised machine learning algorithm that works in conjunction with the ISM to produce a probabilistic distribution of when future maneuvers will occur. The supervised approach uses a Support Vector Machine (SVM) to process the orbit state whereas the ISM processes the temporal intervals between maneuvers and the physics-based characteristics of the maneuvers. This multiple model approach capitalizes on the mathematical strengths of each respective algorithm while incorporating multiple features and inputs. Initial findings indicate that the combined

  10. 46 CFR 109.564 - Maneuvering characteristics.

    Science.gov (United States)

    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...

  11. [Internal carotid artery dissection after Heimlich maneuver].

    Science.gov (United States)

    Rakotoharinandrasana, H; Petit, E; Dumas, P; Vandermarcq, P; Gil, R; Neau, J-Ph

    2003-01-01

    We report a case of cervical artery dissection following a Heimlich maneuver. Cervical artery dissections are at the present time well known and are sometimes associated with trivial traumas. However, to our knowledge, this complication of such maneuver was never reported in the literature. Pathophysiological mechanisms are discussed.

  12. Atmospheric Reentry Dispersion Correction Ascent Phase Guidance for a Generic Reentry Vehicle

    Directory of Open Access Journals (Sweden)

    Avinash Chander

    2013-05-01

    Full Text Available Launch vehicle explicit guidance mechanism depends on the estimation of the desired burnout conditions and driving the vehicle to achieve these conditions. The accuracy of the vehicle at the target point depends on how tightly these conditions are achieved and what is the strategy used to define the trajectory. It has been observed inthe literature that most of the guidance mechanisms during reentry use vacuum guidance equations that is durin greentry the atmospheric effects are not considered. In order to achieve minimum miss distance at the target point theat mospheric effects are to be considered during the guided phase and appropriate corrections should be executed,otherwise depending on the reentry flight path angle and ballistic coefficient the errors can be as high as tens of nautical miles. In this paper, the authors develop a novel approach to these vacuum guided launch vehicle problems.The paper elaborates how to calculate a prior the reentry dispersion during the ascent phase guidance and provide guidance corrections such that the terminal conditions are achieved with higher accuracy.Defence Science Journal, 2013, 63(3, pp.233-241, DOI:http://dx.doi.org/10.14429/dsj.63.3733

  13. Aerodynamic maneuvering hypersonic flight mechanics

    Science.gov (United States)

    Desautel, Dick

    1988-01-01

    The emergence of current high-interest mission involving aeromaneuvering hypersonic flight has given rise to the corresponding need for preliminary design and performance analyses of such vehicles. This need in turn has motivated efforts to develop simplified analytical and computational methods for parametric analysis of maneuvering hypersonic flight under conditions appropriate to the mission involved. The effort included a review of different formulations of the general equations of motion, their associated coordinate frames, various simplifications of the equations, and previously achieved analytical solutions. This study sought to both extend previous solution methods and to develop new ones. In addition, evaluation of the literature and developing a systematic perspective on the knowledge it represents proved to be a major portion of the effort.

  14. Gastric rupture after the Heimlich maneuver.

    Science.gov (United States)

    Bintz, M; Cogbill, T H

    1996-01-01

    Since 1975, the Heimlich maneuver has been widely applied to relieve upper airway obstruction caused by aspirated material. Life-threatening complications have been documented following this simple procedure. We report two cases of gastric rupture after use of the Heimlich maneuver. Both patients experienced pulmonary and abdominal symptoms. The diagnosis was confirmed in each case by the demonstration of free intraperitoneal air on an upright chest roentgenogram. Full-thickness gastric rupture along the lesser curvature of the stomach was repaired in both patients; one patient died. Abdominal pain or persistent abdominal distention despite nasogastric suction after the Heimlich maneuver should prompt evaluation for possible gastric rupture.

  15. Development Of Maneuvering Autopilot For Flight Tests

    Science.gov (United States)

    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.

  16. Design of a digital adaptive control system for reentry vehicles.

    Science.gov (United States)

    Picon-Jimenez, J. L.; Montgomery, R. C.; Grigsby, L. L.

    1972-01-01

    The flying qualities of atmospheric reentry vehicles experience considerable variations due to the wide changes in flight conditions characteristic of reentry trajectories. A digital adaptive control system has been designed to modify the vehicle's dynamic characteristics and to provide desired flying qualities for all flight conditions. This adaptive control system consists of a finite-memory identifier which determines the vehicle's unknown parameters, and a gain computer which calculates feedback gains to satisfy flying quality requirements.

  17. Synthetic Imaging Maneuver Optimization (SIMO) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences (AFS), in collaboration with the MIT Space Systems Laboratory (MIT-SSL), proposed the Synthetic Imaging Maneuver Optimization (SIMO) program...

  18. Helicopter stability during aggressive maneuvers

    Science.gov (United States)

    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.

  19. Optimization of satellite constellation reconfiguration maneuvers

    Science.gov (United States)

    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.

  20. Gastric rupture after Heimlich maneuver and cardiopulmonary resuscitation.

    Science.gov (United States)

    Tung, P H; Law, S; Chu, K M; Law, W L; Wong, J

    2001-01-01

    Choking is a common emergency problem. The Heimlich maneuver is unquestionably effective in relieving airway obstruction. Serious and life-threatening complications may arise, however, if the maneuver is applied incorrectly. Two cases of gastric rupture after Heimlich maneuver are reported. Lay public, paramedics and the medical professionals should be educated with the correct technique of Heimlich maneuver and its potential complications. All patients receiving Heimlich maneuver should be examined by an experienced physician.

  1. An adaptive guidance algorithm for an aerodynamically assisted orbital plane change maneuver. M.S. Thesis

    Science.gov (United States)

    Blissit, J. A.

    1986-01-01

    Using analysis results from the post trajectory optimization program, an adaptive guidance algorithm is developed to compensate for density, aerodynamic and thrust perturbations during an atmospheric orbital plane change maneuver. The maneuver offers increased mission flexibility along with potential fuel savings for future reentry vehicles. Although designed to guide a proposed NASA Entry Research Vehicle, the algorithm is sufficiently generic for a range of future entry vehicles. The plane change analysis provides insight suggesting a straight-forward algorithm based on an optimized nominal command profile. Bank angle, angle of attack, and engine thrust level, ignition and cutoff times are modulated to adjust the vehicle's trajectory to achieve the desired end-conditions. A performance evaluation of the scheme demonstrates a capability to guide to within 0.05 degrees of the desired plane change and five nautical miles of the desired apogee altitude while maintaining heating constraints. The algorithm is tested under off-nominal conditions of + or -30% density biases, two density profile models, + or -15% aerodynamic uncertainty, and a 33% thrust loss and for various combinations of these conditions.

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

    Science.gov (United States)

    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.

  3. Partitioning kinetic energy during freewheeling wheelchair maneuvers.

    Science.gov (United States)

    Medola, Fausto O; Dao, Phuc V; Caspall, Jayme J; Sprigle, Stephen

    2014-03-01

    This paper describes a systematic method to partition the kinetic energy (KE) of a free-wheeling wheelchair. An ultralightweight rigid frame wheelchair was instrumented with two axle-mounted encoders and data acquisition equipment to accurately measure the velocity of the drive wheels. A mathematical model was created combining physical specifications and geometry of the wheelchair and its components. Two able-bodied subjects propelled the wheelchair over four courses that involved straight and turning maneuvers at differing speeds. The KE of the wheelchair was divided into three components: translational, rotational, and turning energy. This technique was sensitive to the changing contributions of the three energy components across maneuvers. Translational energy represented the major component of total KE in all maneuvers except a zero radius turn in which turning energy was dominant. Both translational and rotational energies are directly related to wheelchair speed. Partitioning KE offers a useful means of investigating the dynamics of a moving wheelchair. The described technique permits analysis of KE imparted to the wheelchair during maneuvers involving changes in speed and direction, which are most representative of mobility in everyday life. This technique can be used to study the effort required to maneuver different types and configurations of wheelchairs.

  4. Can Social Capital Networks Assist Re-entry Felons to Overcome Barriers to Re-entry and Reduce Recidivism?

    Directory of Open Access Journals (Sweden)

    Earl Smith

    2011-05-01

    Full Text Available Based on interviews with 25 reentry felons, this article examines the impact that social capital plays in successful reentry; specifically with securing stable housing and employment. We found that access to social capital allowed those with the lowest probability for success—African American men with felony convictions—to secure both stable employment and housing and thus avoid engaging in illegitimate behavior that leads to recidivism. The findings suggest that even for those individuals reentering society with the most strikes against them (as noted by researchers such as Pager and Travis, access to the resource rich social capital networks provided by reentry programs can allow these individuals to overcome the barriers to reentry and find stable jobs and secure housing. Our findings suggest that more research be done on the impact of social capital embedded in reentry programs and that referrals be made to these types of programs and funding be provided for those that demonstrate the ability to significantly reduce recidivism. As Putman has noted, "Just as a screwdriver (physical capital or a college education (human capital can increase productivity (both individual and collective, so do social contacts affect the productivity of individuals and groups."

  5. Computational Hypersonic Aerodynamics with Emphasis on Earth Reentry Capsules

    Directory of Open Access Journals (Sweden)

    Mihai Leonida NICULESCU

    2016-09-01

    Full Text Available The temperature in the front region of a hypersonic vehicle nose can be extremely high, for example, reaching approximately 11 000 K at a Mach number of 36 (Apollo reentry due to the bow shock wave. In this case, accurate prediction of temperature behind the shock wave is necessary in order to precisely estimate the wall heat flux. A better prediction of wall heat flux leads to smaller safety coefficient for thermal shield of space reentry vehicle; therefore, the size of thermal shield decreases and the payload could increase. However, the accurate prediction of temperature behind the bow shock wave implies the use of a precise chemical model whose partial differential equations are added to Navier-Stokes equations. This second order partial differential system is very difficult to be numerically integrated. For this reason, the present paper deals with the computational hypersonic aerodynamics with chemical reactions with the aim of supporting Earth reentry capsule design.

  6. Pesticides re-entry dermal exposure of workers in greenhouses.

    Science.gov (United States)

    Caffarelli, V; Conte, E; Correnti, A; Gatti, R; Musmeci, F; Morali, G; Spagnoli, G; Tranfo, G; Triolo, L; Vita, M; Zappa, G

    2004-01-01

    This research has the aim to evaluate the risk of pesticide dermal exposure for workers in greenhouses. We considered the following crops: tomato, cucumber and strawberry, largely spread in Bracciano lake district. The pesticides monitored were: tetradifon on strawberry: metalaxyl, azoxystrobin and fenarimol on cucumber; acrinathrin, azoxystrobin and chlorpyrifos ethyl on tomato. The dermal exposure was evaluated by Dislodgeable Foliar Residue (DFR) measurements employing transfer coefficients got from literature. For risk evaluation, we have compared the dermal exposures with Acceptable Operator Exposure Levels (AOEL). The re-entry time were obtained intercepting the dose decay curves with AOEL values. The re-entry times result higher than two days in the cases of chlorpyrifos on tomato (re-entry time: 3 days), azoxystrobin on tomato (4 days), and tetradifon on strawberry (8 days). The need of measuring specific transfer coefficients is pointed out.

  7. Emittance of TD-NiCr after simulated reentry

    Science.gov (United States)

    Clark, R. K.; Dicus, D. L.; Lisagor, W. B.

    1978-01-01

    The effects of simulated reentry heating on the emittance of TD-NiCr were investigated. Groups of specimens with three different preconditioning treatments were exposed to 6, 24, and 30 half-hour simulated reentry exposure cycles in a supersonic arc tunnel at each of three conditions intended to produce surface temperatures of 1255, 1365, and 1475 K. Emittance was determined at 1300 K on specimens which were preconditioned only and specimens after completion of reentry simulation exposure. Oxide morphology and chemistry were studied by scanning electron microscopy and X-ray diffraction analysis. A consistent relationship was established between oxide morphology and total normal emittance. Specimens with coarser textured oxides tended to have lower emittances than specimens with finer textured oxides.

  8. MANEUVERING TARGET TRACKING USING FUZZY COMPENSATOR

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    A new approach is provided to estimate the state of arbitrarily maneuvering target. In this approach a fuzzy compensator is used to tackle the uncertainty which results from the targets arbitrarily maneuvering. To design the observer of the nonlinear system, the fuzzy T-S model and the receding horizon control strategy are employed. Besides, the design depends on tracking the output error of the model. Compared with the technique used in other articles, the errors between the first estimated value and the true state value of the estimated variable are not strictly required. Numerical simulating results show that the proposed approach can estimate the states of the random maneuvering targets on-line so as to obtain the exact tracking of the target.

  9. Close approach maneuvers around an oblate planet

    Science.gov (United States)

    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.

  10. Analysis of Maneuvering Flight of an Insect

    Institute of Scientific and Technical Information of China (English)

    Sunada S.; Wang H.; Zeng Lijiang; Kawachi K.

    2004-01-01

    Wing motion of a dragonfly in the maneuvering flight, which was measured by Wang et al. [1] was investigated. Equations of motion for a maneuvering flight of an insect were derived. These equations were applied for analyzing the maneuvering flight. Inertial forces and moments acting on a body and wings were estimated by using these equations and the measured motions of the body and the wings. The results indicated the following characteristics of this flight: (1) The phase difference in flapping motion between the two fore wings and two hind wings, and the phase difference between the flapping motion and the feathering motion of the four wings are equal to those in a steady forward flight with the maximum efficiency. (2)The camber change and the feathering motion were mainly controlled by muscles at the wing bases.

  11. The Heimlich maneuver: breaking down the complications.

    Science.gov (United States)

    Chillag, Shawn; Krieg, Jake; Bhargava, Ranjana

    2010-02-01

    The very young and the very old are vulnerable to choking, and there are over 4000 choking-related deaths annually in the United States. Complications from the Heimlich maneuver (HM), as reported in infrequent case reports, predominantly relate to the elderly. It is doubtful that the denominator, numerator, appropriateness, expertise, and problems of maneuvers applied to choking victims will ever be known. This case report and literature review suggests that the treatment for acute elderly choking victims should be applied carefully and that esophageal food impaction, which should be rapidly distinguishable from choking, can have serious complications with application of the HM.

  12. Towboat Maneuvering Simulator. Volume III. Theoretical Description.

    Science.gov (United States)

    1979-05-01

    overshoot or :igzag maneuver;I - 1,2,3 .. . 6FL F- _’ Flan"ing rudder deflection rate a _ __ Steering rudder deflection rate Ship propulsion ratlol " elh...used with the equations are for the ship propulsion point (n - 1.0). The equations are written in terms of the complete barge flotillia towboat

  13. Air Combat Maneuvering Expert System Trainer

    Science.gov (United States)

    1992-01-01

    AL-TP-1 991-0058....... AD-A246 459 AIR COMBAT MANEUVERING EXPERT A SYSTEM TRAINER R M S Robert J. BechtelTI T Markt Technology, incorporated ’T R...would have to be established for each segment of pilot training. The success of the air intercept trainer (AT), which shares some features with ACMEST

  14. Perforated stomach following the Heimlich maneuver.

    Science.gov (United States)

    Cowan, M; Bardole, J; Dlesk, A

    1987-03-01

    The use of infradiaphragmatic abdominal pressure for relief of airway obstruction caused by food was first described by Henry Heimlich in 1974. Since that time, several complications have been reported. We report a case of gastric perforation occurring in a choking victim following the application of the Heimlich maneuver.

  15. About avatars and maneuvering in virtual environments

    NARCIS (Netherlands)

    Delleman, N.

    2006-01-01

    This paper is about the use of avatars and maneuvering in virtual environments for simulation-based design ergonomics. An avatar is a digital human model driven by an instrumented human who is immersed in a virtual environment. A presentation on locomotion devices is followed by descriptions of vari

  16. 14 CFR 23.1507 - Operating maneuvering speed.

    Science.gov (United States)

    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...

  17. Verapamil reduces incidence of reentry during ventricular fibrillation in pigs.

    Science.gov (United States)

    Jin, Qi; Dosdall, Derek J; Li, Li; Rogers, Jack M; Ideker, Raymond E; Huang, Jian

    2014-11-01

    The characteristics of reentrant circuits during short duration ventricular fibrillation (SDVF; 20 s in duration) and the role of Ca(++) and rapid-activating delayed rectifier potassium currents during long duration ventricular fibrillation (LDVF; up to 10 min in duration) were investigated using verapamil and sotalol. Activation mapping of the LV epicardium with a 21 × 24 electrode plaque was performed in 12 open-chest pigs. Pigs were given either verapamil (0.136 mg/kg) or sotalol (1.5 mg/kg) and verapamil. Reentry patterns were quantified for SDVF, and, for LDVF, activation patterns were compared with our previously reported control LDVF data. Verapamil significantly increased conduction velocity around the reentrant core by 10% and reduced the reentrant cycle length by 15%, with a net reduction in reentry incidence of 70%. Sotolol had an opposite effect of decreasing the conduction velocity around the core by 6% but increasing the reentrant cycle length by 13%, with a net reduction of reentry incidence of 50%. After 200 s of VF, verapamil significantly slowed wavefront conduction velocity and activation rate compared with control data. Verapamil decreased the incidence of reentry in SDVF by accelerating conduction velocity to increase the likelihood of conduction block, possibly through increased sympathetic tone. The drug slowed activation rate and conduction velocity after 200 s of VF, suggesting that L-type Ca(++) channels remain active and may be important in the maintenance of LDVF. Sotalol in addition to verapamil caused no additional antiarrhythmic effect.

  18. Reentry trajectory optimization for hypersonic vehicle satisfying complex constraints

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhao; Rui Zhou

    2013-01-01

    The reentry trajectory optimization for hypersonic vehicle (HV) is a current problem of great interest. Some complex constraints, such as waypoints for reconnaissance and no-fly zones for threat avoidance, are inevitably involved in a global strike mission. Of the many direct methods, Gauss pseudospectral method (GPM) has been demonstrated as an effective tool to solve the tra-jectory optimization problem with typical constraints. However, a series of difficulties arises for complex constraints, such as the uncertainty of passage time for waypoints and the inaccuracy of approximate trajectory near no-fly zones. The research herein proposes a multi-phase technique based on the GPM to generate an optimal reentry trajectory for HV satisfying waypoint and no-fly zone constraints. Three kinds of specific breaks are introduced to divide the full trajectory into multiple phases. The continuity conditions are presented to ensure a smooth connection between each pair of phases. Numerical examples for reentry trajectory optimization in free-space flight and with complex constraints are used to demonstrate the proposed technique. Simulation results show the feasible application of multi-phase technique in reentry trajectory optimization with way-point and no-fly zone constraints.

  19. Reentry Issues upon Returning from Study Abroad Programs

    Science.gov (United States)

    Wielkiewicz, Richard M.; Turkowski, Laura W.

    2010-01-01

    The impact of returning from studying abroad was surveyed in 669 college students. Students who studied abroad scored significantly higher on a Reentry Shock scale, reflecting skepticism toward U.S. culture, than those who did not. They were also more likely to consume alcohol. Study abroad had no detectable influence on students' romantic…

  20. Astronauts McNair and Stewart prepare for reentry

    Science.gov (United States)

    1984-01-01

    Astronauts Ronald E. McNair and Robert L. Stewart prepare for the re-entry phase of the shuttle Challenger near the end of the 41-B mission. The are stationed behind the crew commander and pilot. Stewart is already wearing his helmet. McNair is stowing some of his gear.

  1. Childhood cancer survivors' school (re)entry: Australian parents' perceptions.

    Science.gov (United States)

    McLoone, J K; Wakefield, C E; Cohn, R J

    2013-07-01

    Starting or returning to school after intense medical treatment can be academically and socially challenging for childhood cancer survivors. This study aimed to evaluate the school (re)entry experience of children who had recently completed cancer treatment. Forty-two semi-structured telephone interviews were conducted to explore parents' perceptions of their child's (re)entry to school after completing treatment (23 mothers, 19 fathers, parent mean age 39.5 years; child mean age 7.76 years). Interviews were analysed using the framework of Miles and Huberman and emergent themes were organised using QSR NVivo8. Parents closely monitored their child's school (re)entry and fostered close relationships with their child's teacher to ensure swift communication of concerns should they arise. The most commonly reported difficulty related to aspects of peer socialisation; survivors either displayed a limited understanding of social rules such as turn taking, or related more to older children or teachers relative to their peers. Additionally, parents placed a strong emphasis on their child's overall personal development, above academic achievement alone. Improved parent, clinician and teacher awareness of the importance of continued peer socialisation during the treatment period is recommended in order to limit the ongoing ramifications this may have on school (re)entry post-treatment completion.

  2. School Reentry for Children with Acquired Central Nervous Systems Injuries

    Science.gov (United States)

    Carney, Joan; Porter, Patricia

    2009-01-01

    Onset of acquired central nervous system (CNS) injury during the normal developmental process of childhood can have impact on cognitive, behavioral, and motor function. This alteration of function often necessitates special education programming, modifications, and accommodations in the education setting for successful school reentry. Special…

  3. Kuder Occupational Interest Survey Profiles of Reentry Women

    Science.gov (United States)

    Tittle, Carol K.; Denker, Elenor R.

    1977-01-01

    The Kuder Occupational Interest Survey was administered to 202 women considering reentry into education. It was found that the KOIS does differentiate between women and individual interests are reflected for this sample of women. It was concluded that examination of male-normed scales is very useful in counseling. (Author)

  4. Algorithm of Impact Point Prediction for Intercepting Reentry Vehicles

    Directory of Open Access Journals (Sweden)

    Cheng-Yu Liu

    2006-04-01

    Full Text Available Intercepting reentry vehicles is difficult because these move nearly at hypersonic speedsthat traditional interceptors cannot match. Counterparallel guidance law was developed fordefending a high speed target that guides the interceptor to intercept the target at a 180° aspectangle. When applying the counterparallel guidance law, it is best to predict the impact pointbefore launch. Estimation and prediction of a reentry vehicle path are the first steps in establishingthe impact point prediction algorithm. Model validation is a major challenge within the overalltrajectory estimation problem. The adaptive Kalman filter, consising of an extended Kalman filterand a recursive input estimator, accurately estimates reentry vehicle trajectory by means of aninput estimator which processes the model validation problem. This investigation presents analgorithm of impact point prediction for a reentry vehicle and an interceptor at an optimal interceptaltitude based on the adaptive Kalman filter. Numerical simulation using a set of data, generatedfrom a complicated model, verifies the accuracy of the proposed algorithm. The algorithm alsoperforms exceptionally well using a set of flight test data. The presented algorithm is effectivein solving the intercept problems.

  5. BeppoSAX equatorial uncontrolled re-entry

    Science.gov (United States)

    Portelli, C.

    The X-ray astronomy satellite BeppoSAX (Satellite per Astronomia X, "Beppo" in honor of Giuseppe Occhialini), is a project of the Italian Space Agency (ASI) with participation of the Netherlands Agency for Aerospace Programs (NIVR). BeppoSAX was launched by an Atlas G Centaur directly into a circular 600 km- orbit at 3.9 degrees inclination on April 30th, 1996. The satellite is a three axis stabilized spacecraft with a total mass of about 1400 kg. The current (May 1, 2002) flight altitude is about 470 km and its uncontrolled re-entry is predicted late in 2002, or in 2003, with a 26 kg of hydrazine on board that could not be vented or used for controlled re-entry due to gyro's package total failure. Due to the relatively high mass of BeppoSAX, it has to be expected that parts of the satellite will survive the re-entry into the earth atmosphere. The Italian Space Agency has committed a study to HTG for the analysis of the destructive phase of the uncontrolled atmospheric re-entry by means of a dedicated European software tool (SCARAB). The expected outputs will be used in order to determine how much of the spacecraft and how many fragments parts of it will reach the ground on the equatorial earth zone. This paper will address the peculiarities of the spacecraft initial status, its risks at end of life and the SCARAB modelling as well as its 6D flight dynamics re-entry analysis results also in terms of the destruction history tree. Consideration will be made on the ground dispersion and casualt y area due to the very restricted equatorial zone impacted. References B. Fritsche, H. Klinkrad, A. Kashkovsky, E.Grinberg; Spacecraft Disintegration during uncontrolled atmospheric entry ; IAA-99-IAA.6.7.02; 50t h IAC 4-8 Oct. 1999

  6. Complications as a result of the Heimlich maneuver.

    Science.gov (United States)

    Lee, Steven L; Kim, Stephen S; Shekherdimian, Shant; Ledbetter, Daniel J

    2009-03-01

    The Heimlich maneuver is a well-described emergency procedure for management of foreign body airway obstructions. Although rare, complications of the Heimlich maneuver do exist. The purpose of this report is to review the known complications of this procedure. All reported complications published in English on Medline and PubMed were reviewed. Additionally, we present a rare case of acute pancreatitis with associated pseudocyst formation after the administration of the Heimlich maneuver on a healthy 3-year-old boy. Although life saving, the Heimlich maneuver may be associated with significant complications; thus, symptomatic patients after this maneuver should be thoroughly evaluated with appropriate laboratory and radiographic studies.

  7. Neural fuzzy inference network approach to maneuvering target tracking

    Institute of Scientific and Technical Information of China (English)

    韩红; 刘允才; 韩崇昭; 朱洪艳; 文戎

    2004-01-01

    In target tracking study, the fast target maneuver detecting and highly accurate tracking are very important.And it is difficult to be solved. For the radar/infrared image fused tracking system, a extend Kalman filter combines with a neural fuzzy inference network to be used in maneuvering target tracking. The features related to the target maneuver are extracted from radar, infrared measurements and outputs of tracking filter, and are sent into the neural fuzzy inference network as inputs firstly, and then the target's maneuver inputs are estimated, so that, the accurate tracking is achieved. The simulation results indicate that the new method is valuable for maneuvering target tracking.

  8. Estimating maneuvers for precise relative orbit determination using GPS

    Science.gov (United States)

    Allende-Alba, Gerardo; Montenbruck, Oliver; Ardaens, Jean-Sébastien; Wermuth, Martin; Hugentobler, Urs

    2017-01-01

    Precise relative orbit determination is an essential element for the generation of science products from distributed instrumentation of formation flying satellites in low Earth orbit. According to the mission profile, the required formation is typically maintained and/or controlled by executing maneuvers. In order to generate consistent and precise orbit products, a strategy for maneuver handling is mandatory in order to avoid discontinuities or precision degradation before, after and during maneuver execution. Precise orbit determination offers the possibility of maneuver estimation in an adjustment of single-satellite trajectories using GPS measurements. However, a consistent formulation of a precise relative orbit determination scheme requires the implementation of a maneuver estimation strategy which can be used, in addition, to improve the precision of maneuver estimates by drawing upon the use of differential GPS measurements. The present study introduces a method for precise relative orbit determination based on a reduced-dynamic batch processing of differential GPS pseudorange and carrier phase measurements, which includes maneuver estimation as part of the relative orbit adjustment. The proposed method has been validated using flight data from space missions with different rates of maneuvering activity, including the GRACE, TanDEM-X and PRISMA missions. The results show the feasibility of obtaining precise relative orbits without degradation in the vicinity of maneuvers as well as improved maneuver estimates that can be used for better maneuver planning in flight dynamics operations.

  9. Beta Thalassemia

    Science.gov (United States)

    Beta thalassemia is found in people of Mediterranean, Middle Eastern, African, South Asian (Indian, Pakistani, etc.), Southeast Asian and Chinese descent. 1 Beta Thalassemia ßß Normal beta globin genes found on chromosomes ...

  10. Review of Tracktable for Satellite Maneuver Detection

    Energy Technology Data Exchange (ETDEWEB)

    Acquesta, Erin C.S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Valicka, Christopher G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hinga, Mark B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ehn, Carollan Beret [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    As a tool developed to translate geospatial data into geometrical descriptors, Tracktable offers a highly efficient means to detect anomalous flight and maritime behavior. Following the success of using geometrical descriptors for detecting anomalous trajectory behavior, the question of whether Tracktable could be used to detect satellite maneuvers arose. In answering this question, this re- port will introduce a brief description of how Tracktable has been used in the past, along with an introduction to the fundamental properties of astrodynamics for satellite trajectories. This will then allow us to compare the two problem spaces, addressing how easily the methods used by Tracktable will translate to orbital mechanics. Based on these results, we will then be able to out- line the current limitations as well as possible path forward for using Tracktable to detect satellite maneuvers.

  11. Identifying tacit strategies in aircraft maneuvers

    Science.gov (United States)

    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.

  12. Orbital maneuvering vehicle guidance, navigation and control

    Science.gov (United States)

    Huber, W. G.; Finnell, W., III

    1985-01-01

    This paper describes the Orbital Maneuvering Vehicle (OMV) concept and its intended role. It recaps the past activities leading up to the current concept and summarizes the present status and plans. The various types of missions and operating modes required by the OMV are described as the basis of the guidance, navigation and control (GN&C) requirements. The general GN&C problem is outlined with potential hardware solutions.

  13. Reentry survival analysis of tumbling metallic hollow cylinder

    Science.gov (United States)

    Sim, Hyung-seok; Kim, Kyu-hong

    2011-09-01

    The survival of orbital debris reentering the Earth's atmosphere is considered. The numerical approach of NASA's Object Reentry Survival Analysis Tool (ORSAT) is reviewed, and a new equation accounting for reradiation heat loss of hollow cylindrical objects is presented. Based on these, a code called Survivability Analysis Program for Atmospheric Reentry (SAPAR) has been developed, and the new equation for reradiation heat loss is validated. Using this equation in conjunction with the formulation used in ORSAT, a comparative case study on the Delta-II second stage cylindrical tank is given, demonstrating that the analysis using the proposed equation is in good agreement with the actual recovered object when a practical value for thermal emissivity is used. A detailed explanation of the revised formulation is given, and additional simulation results are presented. Finally, discussions are made to address the applicability of the proposed equation to be incorporated in future survival analyses of orbital debris.

  14. Reentry Programming for High-Risk Offenders: Insights From Participants.

    Science.gov (United States)

    Bender, Kimberly A; Cobbina, Jennifer E; McGarrell, Edmund F

    2016-10-01

    The mass increase in imprisonment of the last two decades has led to an increasing number of adults released from prison. Scholarly accounts of prisoner reentry have demonstrated that incarcerated individuals face barriers on release from prison and that intervention programs are necessary to assist their transition to the community. Here, we build from the insights of previous research by examining how high-risk offenders perceive a reentry program. Using a qualitative approach, our findings suggest that procedural and substantive justice affect their satisfaction and involvement with the program. This study highlights the importance of providing employment opportunities, social support, and fair and respectful delivery of services to assist incarcerated individuals transitioning to the community.

  15. Reentry confined to the atrioventricular node: electrophysiologic and anatomic findings.

    Science.gov (United States)

    Sheinman, M M; Gonzalez, R; Thomas, A; Ullyot, D; Bharati, S; Lev, M

    1982-05-01

    A patient with recurrent disabling, paroxysmal supraventricular tachycardia refractory to drug treatment underwent electrophysiologic studies. The paroxysmal supraventricular tachycardia was found to be due to atrioventricular (A-V) nodal reentry. The patient died shortly after surgical His bundle section and detailed anatomic studies were performed. These showed fatty infiltration of the approaches to the sinoatrial node, atrial preferential pathways, and A-V node and common bundle. The A-V node was mechanically damaged and the common His bundle was completely severed. These abnormalities were clearly delineated and there was no evidence of an atrio-His bundle bypass tract to an accessory A-V node. Specifically, the central fibrous body and pars membranacea were defined and no atrial muscular fibers pierced these structures to joint the A-V bundle. It is concluded that paroxysmal supraventricular tachycardia due to A-V nodal reentry can be confined to the A-V node.

  16. Reentry control of a low-lift maneuverable spacecraft

    Science.gov (United States)

    Roenneke, Axel J.; Well, Klaus H.

    1992-08-01

    Commercial operation of space laboratories will rely on small, unmanned reentry capsules to retrieve experimental products independent from Shuttle services. An example for such a concept is the Space Mail system studied by the ESA. This paper presents a trajectory control system based on linear state feedback to guide and control the reentry glide of low-lifting capsules. A technique to design a time-varying controller is derived and applied. Simulation results of spatial flights over a rotating earth show that the designed controller effectively responds to entry condition offsets on several reference trajectories. Also, the controller is capable of tolerating modified vehicle parameters as well as atmospheric disturbances, and the same controller gain functions are successfully applied to different reference trajectories.

  17. Identification and standardization of maneuvers based upon operational flight data

    Institute of Scientific and Technical Information of China (English)

    Wang Yongjun; Dong Jiang; Liu Xiaodong; Zhang Lixin

    2015-01-01

    To find a way of loads analysis from operational flight data for advanced aircraft, maneuver identification and standardization jobs are conducted in this paper. For thousands of sor-ties from one aircraft, after studying the flight attitude when performing actions, the start and end time of the maneuvers can be determined. According to those time points, various types of maneu-vers during the flight are extracted in the form of multi-parameters time histories. By analyzing the numerical range and curve shape of those parameters, a characteristic data library is established to model all types of maneuvers. Based on this library, a computer procedure using pattern-recogni-tion theory is programmed to conduct automatic maneuver identification with high accuracy. In that way, operational loads are classified according to maneuver type. For a group of identified maneuvers of the same type, after the processes of time normalization, trace shifting, as well as aver-aging and smoothing, the idealization standard time history of each maneuver type is established. Finally, the typical load statuses are determined successfully based on standard maneuvers. The proposed method of maneuver identification and standardization is able to derive operational loads effectively, and might be applied to monitoring loads in Individual Aircraft Tracking Program (IATP).

  18. Reentry safety for the Topaz II Space Reactor: Issues and analyses

    Energy Technology Data Exchange (ETDEWEB)

    Connell, L.W.; Trost, L.C.

    1994-03-01

    This report documents the reentry safety analyses conducted for the TOPAZ II Nuclear Electric Propulsion Space Test Program (NEPSTP). Scoping calculations were performed on the reentry aerothermal breakup and ground footprint of reactor core debris. The calculations were used to assess the risks associated with radiologically cold reentry accidents and to determine if constraints should be placed on the core configuration for such accidents. Three risk factors were considered: inadvertent criticality upon reentry impact, atmospheric dispersal of U-235 fuel, and the Special Nuclear Material Safeguards risks. Results indicate that the risks associated with cold reentry are very low regardless of the core configuration. Core configuration constraints were therefore not established for radiologically cold reentry accidents.

  19. Abdominal aortic thrombosis in association with an attempted Heimlich maneuver.

    Science.gov (United States)

    Roehm, E F; Twiest, M W; Williams, R C

    1983-03-04

    We report herein a case of an incorrectly applied Heimlich maneuver--to the best of our knowledge, the first reported fatal complication associated with a Heimlich maneuver, acute thrombosis of an abdominal aortic aneurysm, and the distal aorta. While the Heimlich maneuver is effective for the relief of foreign body-induced upper airway obstruction, increased efforts should be directed toward instructing the public in correctly recognizing and optimally treating airway obstruction.

  20. Academic Continuity and School Reentry Support as a Standard of Care in Pediatric Oncology.

    Science.gov (United States)

    Thompson, Amanda L; Christiansen, Heather L; Elam, Megan; Hoag, Jennifer; Irwin, Mary Kay; Pao, Maryland; Voll, Megan; Noll, Robert B; Kelly, Katherine Patterson

    2015-12-01

    Clinicians agree that return to school after diagnosis promotes the positive adjustment of children and adolescents with cancer; however, the school reentry process can present challenges. The aim of this review was to critically evaluate the literature on school reentry support for youth with cancer. Seventeen publications were identified. School reentry services were well-received by families and educators; increased teacher and peer knowledge about childhood cancer; influenced peer and educator attitudes toward the patient; and improved communication and collaboration between patients/families, school, and the healthcare team. Evidence supports a strong recommendation for school reentry support for youth with cancer.

  1. High Fidelity Airborne Imaging System for Remote Observation of Space Launch/Reentry Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The utility of airborne remote observation of hypersonic reentry vehicles was demonstrated by the NASA Hypersonic Thermodynamic Infrared Measurement (HYTHIRM)...

  2. Coordination Logic for Repulsive Resolution Maneuvers

    Science.gov (United States)

    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.

  3. Optimum PN Guidance Law for Maneuvering Target

    Institute of Scientific and Technical Information of China (English)

    SUN Bao-cai; QI Zai-kang

    2007-01-01

    An optimum PN guidance law for maneuvering target is developed using optimal control theory. By estimating the target position and setting the cost function, the guidance law can be deduced even without knowing the missile lateral acceleration. Since the quadratic cost function can make a compromise between the miss distance andthe control constraint, the optimum guidance law obtained is more general. Also, introduced line of sight rate as the input, a practical form of this guidance law is derived. The simulation results show the effectiveness of the guidance laws.

  4. The Valsalva maneuver: mechanisms and clinical implications.

    Science.gov (United States)

    Porth, C J; Bamrah, V S; Tristani, F E; Smith, J J

    1984-09-01

    The previous discussion has focused on the mechanisms, both respiratory and circulatory, that occur during the Valsalva maneuver. The increase in intrathoracic pressure that occurs during the Valsalva maneuver incites a sequence of rapid changes in preload and afterload stress. During the strain, venous return to the heart is decreased and peripheral venous pressures become increased. Within the next few beats, systolic and pulse pressures begin to fall while mean arterial pressure remains near (or is elevated above) control levels owing to the transmission of airway pressure. Thus it would appear that the benefits to cardiac contractility derived from a decrease in systolic and pulse pressure are counterbalanced by an increase in mean arterial pressure. Increases in total peripheral resistance that begin after about 7 seconds of strain produce further increases in afterload. Recruitment of autonomically mediated increases in heart rate and cardiac contractility assists the heart to maintain its cardiac output in the presence of diminished venous return. With the increased venous return that accompanies termination of Valsalva strain, there is an increase in diastolic filling and stroke volume output by means of the Frank-Starling mechanism. Heart rate and total peripheral resistance continue to be increased during the immediate poststrain period, and the ejection of an increased stroke volume into a constricted arterial system produces a rapid and marked increase in arterial pressure--the phase IV overshoot with its subsequent slowing of heart rate.

  5. Reentry Thermal Analysis of a Generic Crew Exploration Vehicle Structure

    Science.gov (United States)

    Ko, William L.; Gong, Leslie; Quinn, Robert D.

    2007-01-01

    Comparative studies were performed on the heat-shielding characteristics of honeycomb-core sandwich panels fabricated with different materials for possible use as wall panels for the proposed crew exploration vehicle. Graphite/epoxy sandwich panel was found to outperform aluminum sandwich panel under the same geometry due to superior heat-shielding qualities and lower material density. Also, representative reentry heat-transfer analysis was performed on the windward wall structures of a generic crew exploration vehicle. The Apollo low Earth orbit reentry trajectory was used to calculate the reentry heating rates. The generic crew exploration vehicle has a graphite/epoxy composite honeycomb sandwich exterior wall and an aluminum honeycomb sandwich interior wall, and is protected with the Apollo thermal protection system ablative material. In the thermal analysis computer program used, the TPS ablation effect was not yet included; however, the results from the nonablation heat-transfer analyses were used to develop a "virtual ablation" method to estimate the ablation heat loads and the thermal protection system recession thicknesses. Depending on the severity of the heating-rate time history, the virtual ablation period was found to last for 87 to 107 seconds and the ablation heat load was estimated to be in the range of 86 to 88 percent of the total heat load for the ablation time period. The thermal protection system recession thickness was estimated to be in the range of 0.08 to 0.11 inches. For the crew exploration vehicle zero-tilt and 18-degree-tilt stagnation points, thermal protection system thicknesses of h = {0.717, 0.733} inches were found to be adequate to keep the substructural composite sandwich temperature below the limit of 300 F.

  6. Flap effectiveness appraisal for winged re-entry vehicles

    Science.gov (United States)

    de Rosa, Donato; Pezzella, Giuseppe; Donelli, Raffaele S.; Viviani, Antonio

    2016-05-01

    The interactions between shock waves and boundary layer are commonplace in hypersonic aerodynamics. They represent a very challenging design issue for hypersonic vehicle. A typical example of shock wave boundary layer interaction is the flowfield past aerodynamic surfaces during control. As a consequence, such flow interaction phenomena influence both vehicle aerodynamics and aerothermodynamics. In this framework, the present research effort describes the numerical activity performed to simulate the flowfield past a deflected flap in hypersonic flowfield conditions for a winged re-entry vehicle.

  7. 14 CFR 23.155 - Elevator control force in maneuvers.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Elevator control force in maneuvers. 23.155 Section 23.155 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Controllability and Maneuverability § 23.155 Elevator control force in maneuvers. (a) The elevator control...

  8. 47 CFR 25.282 - Orbit raising maneuvers.

    Science.gov (United States)

    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...

  9. Linking spatial and dynamic models for traffic maneuvers

    DEFF Research Database (Denmark)

    Olderog, Ernst-Rüdiger; Ravn, Anders Peter; Wisniewski, Rafal

    2015-01-01

    For traffic maneuvers of multiple vehicles on highways we build an abstract spatial and a concrete dynamic model. In the spatial model we show the safety (collision freedom) of lane-change maneuvers. By linking the spatial and dynamic model via suitable refinements of the spatial atoms to distance...

  10. A Randomized Trial of a Multimodal Community-Based Prisoner Reentry Program Emphasizing Substance Abuse Treatment

    Science.gov (United States)

    Grommon, Eric; Davidson, William S., II; Bynum, Timothy S.

    2013-01-01

    Prisoner reentry programs continue to be developed and implemented to ease the process of transition into the community and to curtail fiscal pressures. This study describes and provides relapse and recidivism outcome findings related to a randomized trial evaluating a multimodal, community-based reentry program that prioritized substance abuse…

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

    Science.gov (United States)

    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.

  12. Statistical Issues for Uncontrolled Reentry Hazards - Empirical Tests of the Predicted Footprint for Uncontrolled Satellite Reentry Hazards

    Science.gov (United States)

    Matney, M.

    2012-01-01

    A number of statistical tools have been developed over the years for assessing the risk of reentering objects to human populations. These tools make use of the characteristics (e.g., mass, material, shape, size) of debris that are predicted by aerothermal models to survive reentry. The statistical tools use this information to compute the probability that one or more of the surviving debris might hit a person on the ground and cause one or more casualties. The statistical portion of the analysis relies on a number of assumptions about how the debris footprint and the human population are distributed in latitude and longitude, and how to use that information to arrive at realistic risk numbers. Because this information is used in making policy and engineering decisions, it is important that these assumptions be tested using empirical data. This study uses the latest database of known uncontrolled reentry locations measured by the United States Department of Defense. The predicted ground footprint distributions of these objects are based on the theory that their orbits behave basically like simple Kepler orbits. However, there are a number of factors in the final stages of reentry - including the effects of gravitational harmonics, the effects of the Earth's equatorial bulge on the atmosphere, and the rotation of the Earth and atmosphere - that could cause them to diverge from simple Kepler orbit behavior and possibly change the probability of reentering over a given location. In this paper, the measured latitude and longitude distributions of these objects are directly compared with the predicted distributions, providing a fundamental empirical test of the model assumptions.

  13. Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

    Directory of Open Access Journals (Sweden)

    L. Zhao

    2013-01-01

    Full Text Available A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process.

  14. On Re-Entry Prediction of Near Earth Objects with Genetic Algorithm Using KS Elements

    Science.gov (United States)

    Sharma, R. K.; Anilkumar, A. K.; Xavier James Raj, M.; Sabarinath, A.

    2009-03-01

    The accurate orbit prediction of the near-Earth objects is an important requirement for the re-entry and the life time estimation. The method of Kustaanheimo and Stiefel (KS) total energy element equations is one of the powerful methods for orbit prediction. Recently, due to the reentries of large number of risk objects, which posses threat to the human life and property, a great concern is developed in the space scientific community. Consequently, the prediction of risk objects re-entry time and location has got much importance for the proper planning of mitigation strategies and hazard assessment. This paper discusses an integrated procedure for orbit life time prediction combining the KS elements and genetic algorithm (GA). The orbit prediction is carried out by numerically integrating the KS element equations. In this methodology, the ballistic coefficient is estimated from a set of observed orbital parameters in terms of the Two Line Elements (TLE) by minimizing the variance of the predicted re-entry time from different TLE using GA. A software, KSGEN, systematically developed in-house using KS elements and genetic algorithm is utilized for predicting the re-entry time of the risk objects. This software has been effectively used for the prediction of the re-entry time in the past seven re-entry exercise campaigns conducted by the Inter Agency Space Debris Coordination Committee (IADC). The predicted re-entry time matched quite well with the actual re-entry time for all the seven IADC re-entry campaigns. A detailed analysis is carried out with two case studies.

  15. Long-range synchrony and emergence of neural reentry

    Science.gov (United States)

    Keren, Hanna; Marom, Shimon

    2016-11-01

    Neural synchronization across long distances is a functionally important phenomenon in health and disease. In order to access the basis of different modes of long-range synchrony, we monitor spiking activities over centimetre scale in cortical networks and show that the mode of synchrony depends upon a length scale, λ, which is the minimal path that activity should propagate through to find its point of origin ready for reactivation. When λ is larger than the physical dimension of the network, distant neuronal populations operate synchronously, giving rise to irregularly occurring network-wide events that last hundreds of milliseconds to several seconds. In contrast, when λ approaches the dimension of the network, a continuous self-sustained reentry propagation emerges, a regular seizure-like mode that is marked by precise spatiotemporal patterns (‘synfire chains’) and may last many minutes. Termination of a reentry phase is preceded by a decrease of propagation speed to a halt. Stimulation decreases both propagation speed and λ values, which modifies the synchrony mode respectively. The results contribute to the understanding of the origin and termination of different modes of neural synchrony as well as their long-range spatial patterns, while hopefully catering to manipulation of the phenomena in pathological conditions.

  16. Ship maneuvering digital simulator; Simulador digital de manobras de navios

    Energy Technology Data Exchange (ETDEWEB)

    Souza Junior, Jesse Rebello; Tannuri, Eduardo Aoun; Oshiro, Anderson Takehiro [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Naval e Oceanica

    2008-07-01

    This paper reports on two case studies making use of a digital simulator to investigate the maneuvering motions of ships in canals with shallow and restricted waters. The first case study corresponds to a maneuvering analysis conducted for the Port of Rio Grande (RS - Brazil), whose aim was to assess the potential impact upon maneuvers of the presence of a large offshore platform (the PETROBRAS P-53) which is to remain docked for several months at the Port to complete its construction. The second study made use of the simulator to evaluate the maneuvering conditions along the approach route and maneuvering basin of the Port of Ponta do Felix (PR - Brazil). The simulator includes a complete mathematical model of the ship dynamics in the horizontal plane when subjected to wind and current forces. It also comprises detailed models for the action of thrusters and propellers, both fixed and azimuth, employed to control maneuvers and dynamically position ships, as well as rudders and tugboats. He models used by the simulator allow for the effects of shallow and restricted waters, including the increase in resistance and lateral forces, increase in additional mass and the appearance of lateral and vertical suction (squatting). The simulator is implemented via an interactive interface through which the user is able to apply control actions (rudder angle, main engine, thrusters and tugboats) in real time during maneuvers, thereby reproducing to some extent the action of a pilot. (author)

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

    Science.gov (United States)

    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.

  18. Traumatic rupture of the stomach after Heimlich maneuver.

    Science.gov (United States)

    van der Ham, A C; Lange, J F

    1990-01-01

    Fatal complications following the performance of the Heimlich maneuver have been reported. A 76-year-old woman presented to the emergency department with signs of respiratory distress, abdominal pain and distension one day after airway obstruction and subsequent resuscitation. Despite successful immediate laparotomy and repair of a ruptured stomach, she later succumbed to the sequelae of aspiration of gastric contents and dehiscence of the gastric tear. This is the 4th case of stomach rupture and the 7th reported fatal complication following the Heimlich maneuver. It is recommended that persons who undergo the Heimlich maneuver be examined and observed by a physician, as soon as possible, to rule out complications.

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

    Science.gov (United States)

    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.

  20. Precise Orbit Determination of the GOCE Re-Entry Phase

    Science.gov (United States)

    Gini, Francesco; Otten, Michiel; Springer, Tim; Enderle, Werner; Lemmens, Stijn; Flohrer, Tim

    2015-03-01

    During the last days of the GOCE mission, after the GOCE spacecraft ran out of fuel, it slowly decayed before finally re-entering the atmosphere on the 11th November 2013. As an integrated part of the AOCS, GOCE carried a GPS receiver that was in operations during the re-entry phase. This feature provided a unique opportunity for Precise Orbit Determination (POD) analysis. As part of the activities carried out by the Navigation Support Office (HSO-GN) at ESOC, precise ephemerides of the GOCE satellite have been reconstructed for the entire re-entry phase based on the available GPS observations of the onboard LAGRANGE receiver. All the data available from the moment the thruster was switched off on the 21st of October 2013 to the last available telemetry downlink on the 10th November 2013 have been processed, for a total of 21 daily arcs. For this period a dedicated processing sequence has been defined and implemented within the ESA/ESOC NAvigation Package for Earth Observation Satellites (NAPEOS) software. The computed results show a post-fit RMS of the GPS undifferenced carrier phase residuals (ionospheric-free linear combination) between 6 and 14 mm for the first 16 days which then progressively increases up to about 80 mm for the last available days. An orbit comparison with the Precise Science Orbits (PSO) generated at the Astronomical Institute of the University of Bern (AIUB, Bern, Switzerland) shows an average difference around 9 cm for the first 8 daily arcs and progressively increasing up to 17 cm for the following days. During this reentry phase (21st of October - 10th November 2013) a substantial drop in the GOCE altitude is observed, starting from about 230 km to 130 km where the last GPS measurements were taken. During this orbital decay an increment of a factor of 100 in the aerodynamic acceleration profile is observed. In order to limit the mis-modelling of the non-gravitational forces (radiation pressure and aerodynamic effects) the newly developed

  1. Lunar Return Reentry Thermal Analysis of a Generic Crew Exploration Vehicle Wall Structures

    Science.gov (United States)

    Ko, William L.; Tran, Van T.; Bowles, Jeff

    2007-01-01

    Thermostructural analysis was performed on generic crew exploration vehicle (GCEV) heat shielded wall structures subjected to reentry heating rates based on five potential lunar return reentry trajectories. The GCEV windward outer wall is fabricated with a graphite/epoxy composite honeycomb sandwich panel and the inner wall with an aluminum honeycomb sandwich panel. The outer wall is protected with an ablative Avcoat-5026-39H/CG thermal protection system (TPS). A virtual ablation method (a graphical approximation) developed earlier was further extended, and was used to estimate the ablation periods, ablation heat loads, and the TPS recession layer depths. It was found that up to 83 95 percent of the total reentry heat load was dissipated in the TPS ablation process, leaving a small amount (3-15 percent) of the remaining total reentry heat load to heat the virgin TPS and maintain the TPS surface at the ablation temperature, 1,200 F. The GCEV stagnation point TPS recession layer depths were estimated to be in the range of 0.280-0.910 in, and the allowable minimum stagnation point TPS thicknesses that could maintain the substructural composite sandwich wall at the limit temperature of 300 F were found to be in the range of 0.767-1.538 in. Based on results from the present analyses, the lunar return abort ballistic reentry was found to be quite attractive because it required less TPS weight than the lunar return direct, the lunar return skipping, or the low Earth orbit guided reentry, and only 11.6 percent more TPS weight than the low Earth orbit ballistic reentry that will encounter a considerable weight penalty to obtain the Earth orbit. The analysis also showed that the TPS weight required for the lunar return skipping reentry was much more than the TPS weight necessary for any of the other reentry trajectories considered.

  2. Thermal Analysis of Small Re-Entry Probe

    Science.gov (United States)

    Agrawal, Parul; Prabhu, Dinesh K.; Chen, Y. K.

    2012-01-01

    The Small Probe Reentry Investigation for TPS Engineering (SPRITE) concept was developed at NASA Ames Research Center to facilitate arc-jet testing of a fully instrumented prototype probe at flight scale. Besides demonstrating the feasibility of testing a flight-scale model and the capability of an on-board data acquisition system, another objective for this project was to investigate the capability of simulation tools to predict thermal environments of the probe/test article and its interior. This paper focuses on finite-element thermal analyses of the SPRITE probe during the arcjet tests. Several iterations were performed during the early design phase to provide critical design parameters and guidelines for testing. The thermal effects of ablation and pyrolysis were incorporated into the final higher-fidelity modeling approach by coupling the finite-element analyses with a two-dimensional thermal protection materials response code. Model predictions show good agreement with thermocouple data obtained during the arcjet test.

  3. High-Energy Atmospheric Reentry Test Aerothermodynamic Analysis

    Science.gov (United States)

    Mazaheri, Alireza

    2013-01-01

    This paper presents an assessment of the aerothermodynamic environment around an 8.3 meter High Energy Atmospheric Reentry Test (HEART) vehicle. This study generated twelve nose shape configurations and compared their responses at the peak heating trajectory point against the baseline nose shape. The heat flux sensitivity to the angle of attack variations are also discussed. The possibility of a two-piece Thermal Protection System (TPS) design at the nose is also considered, as are the surface catalytic affects of the aeroheating environment of such configuration. Based on these analyses, an optimum nose shape is proposed to minimize the surface heating. A recommendation is also made for a two-piece TPS design, for which the surface catalytic uncertainty associated with the jump in heating at the nose-IAD juncture is reduced by a minimum of 93%. In this paper, the aeroshell is assumed to be rigid and the inflatable fluid interaction effect is left for future investigations

  4. Input shaping control with reentry commands of prescribed duration

    Directory of Open Access Journals (Sweden)

    Valášek M.

    2008-12-01

    Full Text Available Control of flexible mechanical structures often deals with the problem of unwanted vibration. The input shaping is a feedforward method based on modification of the input signal so that the output performs the demanded behaviour. The presented approach is based on a finite-time Laplace transform. It leads to no-vibration control signal without any limitations on its time duration because it is not strictly connected to the system resonant frequency. This idea used for synthesis of control input is extended to design of dynamical shaper with reentry property that transform an arbitrary input signal to the signal that cause no vibration. All these theoretical tasks are supported by the results of simulation experiments.

  5. Re-Entry Guidance Using an Energy-State Equation

    Science.gov (United States)

    Abe, Akio; Shimada, Yuzo; Uchiyama, Kenji

    This paper presents a new guidance and control system for a re-entry vehicle. In the conventional drag acceleration control system employed for the present space shuttles, the velocity is an unobservable state variable and the associated pole tends to be unstable. Therefore, in this study, a condition which allows all the states to be observable is introduced using a state-space linearization method. It is also shown that energy and its rate are appropriate for the state variables. A guidance law is analytically derived on the basis of the obtained state equation with respect to the energy by solving a two-point boundary-value problem. Furthermore, a tracking control system is designed to make the position, velocity, and flight path angle of the vehicle track the reference states generated in the guidance system. Finally, numerical simulation is performed to verify the validity of the obtained plant expression, and the effectiveness of the proposed guidance and control system.

  6. Convected transient analysis for large space structures maneuver and deployment

    Science.gov (United States)

    Housner, J.

    1984-01-01

    Convected-transient analysis techniques in the finite-element method are used to investigate the deployment and maneuver of large spacecraft structures with multiple-member flexible trusses and frames. Numerical results are presented for several sample problems.

  7. Pulsed Electrogasdynamic Thruster for Attitude Control and Orbit Maneuver Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In the Phase I program we successfully demonstrated the feasibility of the Pulsed ElectroGasdynamic (PEG) thruster for attitude control and orbital maneuvering. In...

  8. Pulsed Electrogasdynamic Thruster for Attitude Control and Orbit Maneuver Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new pulsed electric thruster, named "pulsed electrogasdynamic thruster," for attitude control and orbit maneuver is proposed. In this thruster, propellant gas is...

  9. Tongue-Driven Wheelchair Out-Maneuvers the Competition

    Science.gov (United States)

    ... 496-3500 Share Science Highlight: January 2, 2014 Tongue-Driven Wheelchair Out-Maneuvers the Competition Researchers funded ... Imaging and Bioengineering have demonstrated that their novel Tongue Drive System is superior to other assistive devices ...

  10. Space Object Maneuver Detection Algorithms Using TLE Data

    Science.gov (United States)

    Pittelkau, M.

    2016-09-01

    An important aspect of Space Situational Awareness (SSA) is detection of deliberate and accidental orbit changes of space objects. Although space surveillance systems detect orbit maneuvers within their tracking algorithms, maneuver data are not readily disseminated for general use. However, two-line element (TLE) data is available and can be used to detect maneuvers of space objects. This work is an attempt to improve upon existing TLE-based maneuver detection algorithms. Three adaptive maneuver detection algorithms are developed and evaluated: The first is a fading-memory Kalman filter, which is equivalent to the sliding-window least-squares polynomial fit, but computationally more efficient and adaptive to the noise in the TLE data. The second algorithm is based on a sample cumulative distribution function (CDF) computed from a histogram of the magnitude-squared |V|2 of change-in-velocity vectors (V), which is computed from the TLE data. A maneuver detection threshold is computed from the median estimated from the CDF, or from the CDF and a specified probability of false alarm. The third algorithm is a median filter. The median filter is the simplest of a class of nonlinear filters called order statistics filters, which is within the theory of robust statistics. The output of the median filter is practically insensitive to outliers, or large maneuvers. The median of the |V|2 data is proportional to the variance of the V, so the variance is estimated from the output of the median filter. A maneuver is detected when the input data exceeds a constant times the estimated variance.

  11. Flight Simulator: Field of View Utilized in Performing Tactical Maneuvers.

    Science.gov (United States)

    1988-04-01

    were taken in the Simulator for Air-to-Air Combat (SAAC) and the Advanced Simulator for Pilot Training ( ASPT ). During the air-to-ground data collection...ground maneuvers were performed In the Advanced Simulator for Pilot Training ( ASPT ). The data collected provided an estimate of the FOV dimensions that a...tactical maneuvers were conducted in the AFHIRL ASPT located at Williams AFB. The ASPT had a fully instrumnted F-16 cockpit. The g-cueing was available

  12. Braking news: link between crash severity and crash avoidance maneuvers

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2012-01-01

    crash avoidance maneuvers and crash severity, with differences emerging for different critical events. Moreover, results showed two trends:(a) most drivers failed to act when facing critical events and (b) drivers rarely performed crash avoidance maneuvers that were correlated with a higher probability...... of lower crash severity. These trends suggest that efforts to understand the mechanisms of reactions to different critical events should be made to improve in-vehicle warning systems, promote responsible driving behavior, and design forgiving infrastructures....

  13. Nonlinear maneuver autopilot for the F-15 aircraft

    Science.gov (United States)

    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.

  14. Cooperative maneuver enabled UAV relative localization

    Science.gov (United States)

    Strader, Jared

    The ability to localize itself in an environment is essential for any autonomous vehicle. In applications involving multiple Unmanned Aerial Vehicles (UAVs) such as formation flight, surveillance, and mapping, the relative pose of each UAV provides vital information for multiple vehicles to coordinate effectively. The majority of cooperative localization tasks involving multiple UAVs assume the transformation between reference frames, but this information is not always provided in the absence of landmarks or a Global Positioning System (GPS). This thesis presents a method for estimating the relative pose of a pair of UAVs using range-only measurements. In this method, there is no prior information assumed about the relative pose of each UAV. Instead, the trajectories are constrained in order to leverage the circumstances in which the range-only measurements are obtained during flight. To augment this limited information, motion is used to construct a graph of the UAV trajectories using only distance measurements. Using the constructed graph, four potential solutions are derived for the relative pose, and a batch estimate is performed to obtain numerical estimates of each of the four solutions. Using the batch estimate, a cooperative maneuver can be performed in order to obtain a unique solution. The sensitivity to the trajectory and measurement noise are analyzed through a Monte Carlo analysis.

  15. Computation of flow around maneuvering submerged bodies

    Science.gov (United States)

    Govindan, T. R.; Briley, W. R.; Levy, R.

    1988-10-01

    Generalized primary/secondary flow equations and a spatial-marching solution algorithm have been used to develop a procedure to compute the three-dimensional viscous flow around a submerged body in maneuver. The primary/secondary flow equations are an approximation to the Navier-Stokes equations for flows in which a primary flow direction can be identified. Important elements of the approximation are a locally specified primary flow direction and a decomposition of the secondary velocity field to identify a small velocity vector for approximations. No approximations are introduced for pressure in this approach. The primary/secondary flow equations are a well-posed initial-value problem in a spatial coordinate nominally aligned with the primary flow direction and are solved by a sequentially decoupled implicit algorithm. The procedure provides an order to two orders-of-magnitude run time advantage over solution of the Navier-Stokes equations. Results are presented for the flow past an unappended submarine hull in drift at a Reynolds number of 16 million and incidence of 20 degrees. These results are consistent with experimental observations and provide a means to compute the complex three-dimensional viscous flow field economically.

  16. Valsalva maneuver: shortest optimal expiratory strain duration

    Directory of Open Access Journals (Sweden)

    Ramesh K. Khurana, Md

    2011-07-01

    Full Text Available Purpose : To quantitate the level of difficulty and determine consistency of hemodynamic responses with various expiratory strain (ES durations. Methods : Thirty-four healthy subjects performed the Valsalva maneuver (VM with an ES duration of 10, 12, and 15 seconds in random order. Level of difficulty after each trial was rated 1 to 10, with 10 being the most difficult. Blood pressure and heart rate (HR were recorded continuously and non-invasively. Parameters studied were Valsalva ratio (VR, early phase II (IIE, late phase II (IIL, tachycardia latency (TL, bradycardia latency (BL, and overshoot latency (OV-L. Consistency of responses was calculated. Results : Difficulty increased significantly with increased ES duration: 5.1±0.1 (mean±SEM at 10 seconds, 5.9±0.1 at 12 seconds, and 6.8±0.1 at 15 seconds (p<0.001. Phase IIE, TL, BL, OV-L, and VR response did not differ statistically with increasing ES durations, and there were no differences in variability. Phase IIL response increased significantly with increasing ES duration. Phase IIL was poorly delineated in 14 of 102 trials with 10 seconds ES duration. Conclusions : ES duration of 10 seconds created a low level of difficulty in healthy individuals. This strain duration produced consistent hemodynamic response for all parameters tested except IIL phase. The absence of IIL phase with 10 seconds ES should not be interpreted as an indicator of sympathetic vasoconstrictor failure.

  17. An Immunized Aircraft Maneuver Selection System

    Science.gov (United States)

    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.

  18. Maintaining Aura's Orbit Requirements Under New Maneuver Operations

    Science.gov (United States)

    Johnson, Megan; Petersen, Jeremy D.

    2014-01-01

    The Earth Observing System (EOS) Afternoon Constellation consists of five member missions (GCOM-W1, Aqua, CALIPSO, CloudSat, and Aura), each of which maintain a frozen, sun-synchronous orbit with a 16-day repeating ground track that follows the Worldwide Reference System-2 (WRS-2). Under nominal science operations for Aura, the propulsion system is oriented such that the resultant thrust vector is aligned 13.493 degrees away from the velocity vector along the yaw axis. When performing orbit maintenance maneuvers, the spacecraft performs a yaw slew to align the thrust vector in the appropriate direction. A new Drag Make Up (DMU) maneuver operations scheme has been implemented for Aura alleviating the need for the 13.493 degree yaw slew. The focus of this investigation is to assess the impact that no-slew DMU maneuver operations will have on Auras Mean Local Time (MLT) which drives the required along track separation between Aura and the constellation members, as well as Auras frozen orbit properties, eccentricity and argument of perigee. Seven maneuver strategies were analyzed to determine the best operational approach. A mirror pole strategy, with maneuvers alternating at the North and South poles, was implemented operationally to minimize impact to the MLT. Additional analysis determined that the mirror pole strategy could be further modified to include frozen orbit maneuvers and thus maintain both MLT and the frozen orbit properties under no-slew operations

  19. Automated maneuver planning using a fuzzy logic algorithm

    Science.gov (United States)

    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.

  20. In-Flight Imaging Systems for Hypervelocity and Re-Entry Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — It is proposed to create a rugged, reliable, compact, standardized imaging system for hypervelocity and re-entry vehicles using sapphire windows, small imagers, and...

  1. 14 CFR 440.12 - Duration of coverage for licensed reentry; modifications.

    Science.gov (United States)

    2010-01-01

    ... analysis conducted to determine MPL and specified in a license order. (b) Financial responsibility required... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING FINANCIAL RESPONSIBILITY Financial Responsibility for...) For reentry, insurance coverage required under § 440.9, or other form of financial...

  2. Lightweight Ultrahigh Temperature CMC-Encased C/C Structure for Reentry and Hypersonic Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The reentry spacecraft and hypersonic cruisers of the future will require advanced lightweight thermal protection systems that can provide the dual functionality of...

  3. Low-Subsonic-Speed Static Longitudinal Stability and Control Characteristics of a Winged Reentry-Vehicle Configuration Having Wingtip Panels that Fold up for High-Drag Reentry

    Science.gov (United States)

    Ware, George M.

    1960-01-01

    An investigation of the low-subsonic-speed static longitudinal stability and control characteristics of a model of a manned reentry-vehicle configuration capable of high-drag reentry and glide landing has been a made in the Langley free-flight tunnel. The model had a modified 63 deg delta plan-form wing with a fuselage on the upper surface. This configuration had wingtip panels designed to fold up 90 deg for the high-drag reentry phase of the flight and to extend horizontally for the glide landing. Data for the basic configurations and modifications to determine the effects of plan form, wingtip panel incidence, dihedral, and vertical position of the wingtip panels are presented without analysis.

  4. A re-entry tachycardia triggered by the spontaneous interruption of an atrial tachycardia.

    Science.gov (United States)

    Buttà, Carmelo; Tuttolomondo, Antonino; Di Raimondo, Domenico; Giarrusso, Lucia; Miceli, Giuseppe; Cuttitta, Francesco; La Rosa, Donata; Licata, Giuseppe; Pinto, Antonio

    2015-01-01

    The common atrioventricular nodal re-entry tachycardia is the most common form of paroxysmal supraventricular tachycardia. It starts frequently with a supraventricular ectopic beat that, on finding the fast pathway in refractory period, travels in the slow pathway as to appear as a prolongation of the PR interval on the ECG. In this study, we show a singular case of a common atrioventricular nodal re-entry tachycardia triggered by the spontaneous interruption of an atrial tachycardia.

  5. [Injectable and oral propafenone in nodal reentry and pathways of ventricular preexcitation].

    Science.gov (United States)

    Fauchier, J P; Cosnay, P; Moquet, B; Rouesnel, P; Kapusta, P; Vrancea, F

    1986-09-01

    Propafenone, an antiarrhythmic drug of IC type, was applied to 10 patients with supraventricular tachycardia (SVT) produced by intranodal reentry (group I) and in 14 patients with reentry by an accessory atrioventricular (AV) pathway (group II), 10 of them suffering from orthodromic SVT. Propafenone given intravenously depresses or blocks the antegrade or retrograde conduction in the AV node and in the accessory AV pathway. The same effect is observed with orally given propafenone: 66% of antegrade blocking and 54% of retrograde blocking of the accessory conduction pathway. Intravenously given propafenone reduces within 2 to 3 min by antegrade or retrograde blocking 70% of SVT produced by intranodal reentry and by 85% of SVT produced by reentry by the accessory pathway. After injection it becomes impossible to induce intranodal SVT in 60% of cases and SVT by the accessory pathway reentry in 28% of cases. With oral treatment (600 mg/day) reinduction of intranodal SVT becomes impossible in 66% of cases and of SVT produced by reentry by the accessory pathway in 42% of cases. Long-term oral administration (17 +/- 3.7 months) of the same dose prevents 88% of SVT produced by internodal reentry and 80% of spontaneous SVT produced by reentry by the accessory pathway. Cardiologic tolerance is satisfactory: one case of atrioventricular and intraventricular dysrhythmia is observed. The same holds true for general tolerance: in 2 cases drug administration is discontinued and 11 patients present neurologic and digestive troubles improving after lowering the dosage or increasing the fractionation.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Computer simulation analysis of the effects of countermeasures for reentry orthostatic intolerance

    Science.gov (United States)

    Srinivasan, R. S.; Simanonok, K. E.; Charles, J. B.

    1992-01-01

    Fluid loading is a countermeasure currently in routine use to improve the g-tolerance of crewmembers during reentry and return of Shuttle flights. However, its effectiveness diminishes with mission duration. Countermeasures that will be effective on long-duration flights are needed and are presently under development. This paper discusses the application of computer simulation in the analysis of the effects of countermeasures for reentry orthostatic intolerance. The results suggest improvements upon the fluid loading countermeasure currently in use.

  7. [Epicardial cartography and surgical treatment by simple ventriculotomy of certain resistant re-entry ventricular tachycardias].

    Science.gov (United States)

    Fontaine, G; Guiraudon, G; Frank, R; Gerbaux, A; Cousteau, J P; Barrillon, A; Gay, J; Cabrol, C; Facquet, J

    1975-02-01

    Intraventricular reentry has been prooved by pre-operative electrophysiological studies in two patients without coronary artery disease and resistant ventricular tachycardia. A simple ventriculotomy oriented by epicardial mapping during tachycardia was successfull with a background of 9 and 14 months respectively. In addition, delayed epicardial potentials put into evidence an intraventricular reentry in human myocardium. This new method holds promises for the treatment of some resistant ventricular tachycardia.

  8. Re-entry into the true lumen from the subintimal space.

    Science.gov (United States)

    Schneider, Peter A; Caps, Michael T; Nelken, Nicolas

    2013-08-01

    Endovascular reconstruction of the femoral and popliteal arteries is replacing femoral-popliteal bypass. This is made possible by subintimal recanalization to manage long chronic total occlusions. Re-entry into the true lumen is the most challenging step in this process. This article summarizes the techniques for re-entry into the true lumen in the superficial femoral and above- and below-the-knee popliteal arteries.

  9. An overview of Suomi NPP VIIRS calibration maneuvers

    Science.gov (United States)

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

    2012-09-01

    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). Onorbit 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 multiorbit 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 provides 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

  10. Methods of rapid orbit forecasting after maneuvers for geostationary satellites

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A geostationary(GEO) satellite may serve as a navigation satellite,but there is a problem that maneuvers frequently occur and the forces are difficult to model.Based on the technique of determining satellite orbits by transfer,a predicted orbit with high accuracy may be achieved by the method of statis-tical orbit determination in case of no maneuver force.The predicted orbit will soon be invalid after the maneuver starts,and it takes a long time to get a valid orbit after the maneuver ends.In order to improve ephemeris usability,the method of rapid orbit forecasting after maneuvers is studied.First,GEO satellite movement is analyzed in case of maneuvers based on the observation from the orbit meas-urement system by transfer.Then when a GEO satellite is in the free status just after maneuvers,the short arc observation is used to forecast the orbit.It is assumed that the common system bias and biases of each station are constant,which can be obtained from orbit determination with long arc observations.In this way,only 6 orbit elements would be solved by the method of statistical orbit determination,and the ephemeris with high accuracy may be soon obtained.Actual orbit forecasting with short arc observation for SINOSAT-1 satellite shows that,with the tracking network available,the precision of the predicted orbit(RMS of O-C) can reach about 5 m with 15 min arc observation,and about 3 m with 30 min arc observation.

  11. Methods of rapid orbit forecasting after maneuvers for geostationary satellites

    Institute of Scientific and Technical Information of China (English)

    YANG XuHai; LI ZhiGang; FENG ChuGang; GUO Ji; SHI HuLi; AI GuoXiang; WU FengLei; QIAO RongChuan

    2009-01-01

    A geostationary (GEO) satellite may serve as a navigation satellite,but there is a problem that maneuvers frequently occur and the forces are difficult to model.Based on the technique of determining setellite orbits by transfer,a predicted orbit with high accuracy may be achieved by the method of statistical orbit determination in case of no maneuver force.The predicted orbit will soon be invalid after the maneuver starts,and it takes a long time to get a valid orbit after the maneuver ends.In order to improve ephemeris usability,the method of rapid orbit forecasting after maneuvers is studied.First,GEO satellite movement is analyzed in case of maneuvers based on the observation from the orbit measurement system by transfer.Then when a GEO satellite is in the free status just after maneuvers,the short arc observation is used to forecast the orbit.It is assumed that the common system bias and biases of each station are constant,which can be obtained from orbit determination with long arc observations.In this way,only 6 orbit elements would be solved by the method of statistical orbit determination,and the ephemeris with high accuracy may be soon obtained.Actual orbit forecasting with short arc observation for SlNOSAT-1 satellite shows that,with the tracking network available,the precision of the predicted orbit (RMS of O-C) can reach about 5 m with 15 min arc observation,and about 3 m with 30 min arc observation.

  12. GPK-2 re-entry and deepening -- a technical report

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, J.; Gerard, A.; Barla, R.; Socomine, S.A.

    1999-01-01

    Between mid February to end of May 1999 (in 104 days) the well GPK2 at the Soultz HDR site was successfully re-entered and deepened from 3876 m to a final depth of 5084 m and fully completed. Re-entry included the pulling of the existing 321 1 m long internal 9 5/8-inch by 7-inch casing string, fishing of a submersible pump and some 150 m of 2 3/8-inch tubing, sealing of a major loss zone and opening of a 6 1/4-inch well section in granite (3211-3876 m) to 8 1/2-inch hole size. The well was extended to 5048 m in 8 1/2'' hole size and again completed with a floating 9 5/8-inch by 7-inch casing string. The casing shoe is at 4431 m. A bottom hole core was taken in the depth range 5048-5051 m. The core recovery was app. 40%. A pilot hole in 6 1/4-inch was drilled from 5051-5084 m for in situ stress measurements using the hydraulic fracturing technique. The re-entry and deepening of the well GPK2 was accompanied by several technical developments. New casing packer elements based on inflatable metal shells were developed in a close cooperation between SOCOMINE and MeSy GmbH (patent pending). These packer elements were successfully integrated into the completion of the well. The full weight of the casing string is supported by these elements which are filled with and imbedded in cement. High temperature cementing strategies (up to 170-190 C) for the complex saline fluids encountered in Soultz (High Magnesium Resistant Cements) were developed in a cooperation between Schlumberger Dowell (Vechta), SOCOMINE, SII of Houston, Ruhr-University Bochum, BGR Hannover and IFP Paris. The development of several high temperature logging tools (200 C range, 6-arm caliper, PTF probe) was initiated with CSMA (Cornwall) during the preparation of the deepening of GPK2. Initial scientific investigations included borehole logging (NGS, CLIPER, ARI, UBI, TEMPERATURE), geological investigations (cuttings, core) and seismic monitoring while drilling. During the first temperature log

  13. "The stress will kill you": prisoner reentry as experienced by family members and the urgent need for support services.

    Science.gov (United States)

    Grieb, Suzanne M; Crawford, Amelia; Fields, Julie; Smith, Horace; Harris, Richard; Matson, Pamela

    2014-08-01

    The role of incarceration and community reentry after incarceration has been studied extensively for individual and community health; however, little attention has been given to the experiences of individuals who provide support to those in reentry. Through a community-academic partnership, seven focus groups were conducted with 39 individuals supporting a family member in reentry in the summer of 2012. The primary objectives of the focus groups were to explore community experiences and perspectives regarding providing support during a family member's reentry from a period of incarceration and any desired support for themselves during this time. Five themes emerged under a metatheme of stress, indicating that family members experience acute stress as a result of family reentry that adds to the chronic stress they already endure. Programs that acknowledge the difficult role of family members as supporters during an individual's reentry and provide support to them are desperately needed.

  14. Dynamic cerebral autoregulation changes during sub-maximal handgrip maneuver.

    Directory of Open Access Journals (Sweden)

    Ricardo C Nogueira

    Full Text Available PURPOSE: We investigated the effect of handgrip (HG maneuver on time-varying estimates of dynamic cerebral autoregulation (CA using the autoregressive moving average technique. METHODS: Twelve healthy subjects were recruited to perform HG maneuver during 3 minutes with 30% of maximum contraction force. Cerebral blood flow velocity, end-tidal CO₂ pressure (PETCO₂, and noninvasive arterial blood pressure (ABP were continuously recorded during baseline, HG and recovery. Critical closing pressure (CrCP, resistance area-product (RAP, and time-varying autoregulation index (ARI were obtained. RESULTS: PETCO₂ did not show significant changes during HG maneuver. Whilst ABP increased continuously during the maneuver, to 27% above its baseline value, CBFV raised to a plateau approximately 15% above baseline. This was sustained by a parallel increase in RAP, suggestive of myogenic vasoconstriction, and a reduction in CrCP that could be associated with metabolic vasodilation. The time-varying ARI index dropped at the beginning and end of the maneuver (p<0.005, which could be related to corresponding alert reactions or to different time constants of the myogenic, metabolic and/or neurogenic mechanisms. CONCLUSION: Changes in dynamic CA during HG suggest a complex interplay of regulatory mechanisms during static exercise that should be considered when assessing the determinants of cerebral blood flow and metabolism.

  15. Orbital maneuvers around irregular shaped bodies

    Science.gov (United States)

    Venditti, Flaviane; Rocco, E. M.; Almeida Prado, A. B.

    2013-05-01

    Abstract (2,250 Maximum Characters): In the solar system there are many small bodies called asteroids. The large majority of these bodies are located in the asteroid belt, between the orbits of the planets Mars and Jupiter. The Near- Earth Objects, or NEOs, are objects with perihelion below 1.3AU, which include comets and asteroids. The NEOs are considered to have orbits passing close to the Earth’s orbit and, in the case of asteroids, are called Near-Earth Asteroids (NEAs). Among the NEAs there are bodies considered potentially hazardous asteroids (PHAs), whose minimum orbit intersection distance with Earth is 0.05AU and that have absolute magnitude (H) of 22, which would mean an asteroid of at least 110-240 meters, depending on its albedo. One of the major characteristic of the asteroids is the irregular shape, causing the dynamics of orbits around these bodies to be different from a spherical shaped one. The fact that an object is not spherical generates a perturbation on the gravitational field. The disturbing force can be determined considering the shape of the specific body. A satellite orbiting this body would suffer the effects of this perturbation, but knowing the disturbing force, it’s possible to correct and control the orbit according to the desired mission. The polyhedron method is a traditional way to model an asteroid by dividing the object into smaller parts. The data used on this work are composed by a combination of triangular faces. The total disturbing force is a sum of the force on each piece of the model. Therefore, after the simulations are obtained, it’s possible to apply the desired corrections of the perturbation using continuous low thrust in closed loop, making it possible to perform maneuvers near these bodies. One of the important applications of the study shown above is in the ASTER mission, that is under study by INPE and several other Brazilian academic institutions, which goal is to send a spacecraft to an asteroid and then

  16. Measurement of Tip Trajectories in the Cardiac Reentry

    Institute of Scientific and Technical Information of China (English)

    MING Le-qun; ZHANG Hong; PENG Nian-cai; LI Ming-jun

    2008-01-01

    Reentrant impulse in the myocardium is considered to be a major factor promoting electrophysiological abnormalities or even leading to ventricular tachycardias (VTs) and ventricular fibrillations (VFs). Tip trajectory of the reentrant wave can reflect stability of the electrical propagation and area of the reentrant movement, thereby being considered as one of the most concerned parameters in studying electrical activities during VT/VF. The purpose of the present study is to propose a practical method to find out tip trajectories using a computational approach. In this study Luo-Rudy 1991 mathematical model of the ventricular cell was used. The operator splitting method was utilized to integrate the partial differential equations in the two-dimensional tissue. And spiral waves were initiated by the cut wave front technique. Through experiments we found it was difficult to find out the tips by finding intersection of the two isovoltage lines as proposed in most papers. Therefore, we suggested that tip points were detected by seeking the shortest distance of the two adjacent isovoltage contour lines. The results showed that tip trajectories of these spiral waves found in our way were very near to the tips observed, implying validation of our method in measuring tip trajectories in cardiac reentry.

  17. Ballistic reentry vehicles dispersion due to precession stoppage

    Science.gov (United States)

    Lin, T. C.; Grabowsky, W. R.; Yelmgren, K. E.; Landa, M.

    1982-08-01

    Ballistic reentry vehicle (RV) precession stoppage phenomena are investigated analytically and several postulated reasons for its occurrence are discussed. Both analytical solutions and six-degree-of-freedom (6DOF) simulations are presented. In addition to the familiar phenomena of roll through zero (RTZ), roll near zero (RNZ) and angle-of-attack divergence, there are four additional aerodynamic forcing functions that are found to be particularly interesting and significant since they can induce the so-called 'space-fixed-trim' phenomena, i.e., the lift-vector becomes momentarily stationary in space. These four forcing functions are: (1) a shift from body-fixed to wind-fixed trim moment in high freestream dynamic pressure environments; (2) RV with transient unstable aerodynamic stability derivative; (3) trim plane migrations induced by a series of asymmetric nose spallations, and (4) a Magnus-type out-of-plane moment in conjunction with the wind-fixed moment induced by ablation lag phenomena. When this occurs, the trajectory deflection becomes prohibitively large. According to the present analytical/numerical results, the initial spin rate can be crucial for the magnitude as well as the direction of the RV dispersion. Finally, some possible physical mechanisms which would cause RV precession stoppage are suggested.

  18. Fume hood exhaust re-entry into a chemistry building.

    Science.gov (United States)

    Lamb, B K; Cronn, D R

    1986-02-01

    The rooftop air intakes are in close proximity to the fume hood exhaust vents on the roof of the attached chemistry buildings (Fulmer Hall and Fulmer Annex) at Washington State University. Complaints resulted from the apparent re-entry of hazardous and odorous exhaust vapors and gases returning into the building fresh air supplies. An atmospheric tracer study of the flow patterns and exhaust gas dilution rates determined the suitability of other potential air intake locations. Isopleth maps showed concentration patterns for tests conducted during the different wind regimes (southwest prevailing winds and substantial wintertime southeast periods). As expected, the observed dilution rates were greater than the conservative minimum dilution rates calculated from models. Tracer gas concentrations indicated large areas over which odor thresholds would exceeded for vapors resulting from typical evaporation rates of solvents. Tracer gas concentrations at the building air intakes were about the same as inside building concentrations because little dilution occurred between the intakes and building interiors. Significant infiltration was observed due to negative building pressure relative to outside. The recommendation to move the intakes down the south building walls is being followed since roof-level concentrations are typically a factor of ten or more higher than below-roof levels.

  19. Space Flight and Re-Entry Trajectories : International Symposium

    CERN Document Server

    Libby, Paul A

    1962-01-01

    In this and a following issue (Vol. VIII, 1962, Fasc. 2-3) of "Astronautica Acta" there will appear the papers presented at the first international symposium sponsored by the International Academy of Astronautics of the International Astronautical Federation. The theme of the meeting was "Space Flight and Re-Entry Trajectories." It was held at Louveciennes outside of Paris on June 19-21, 1961. Sixteen papers by authors from nine countries were presented; attendees numbered from 80 to 100. The organizing committee for the symposium was as follows: Prof. PAUL A. LIBBY, Polytechnic Institute of Brooklyn, U.S.A., Chairman; Prof. LuiGI BROGLIO, University of Rome, Italy; Prof. B. FRAEIJS DE VEUBEKE, University of Liege, Belgium; Dr. D. G. KING-HELE, Royal Aircraft Establishment, Farnborough, Rants, United Kingdom; Prof. J. M. J. KooY, Royal Military School, Breda, Netherlands; Prof. JEAN KovALEVSKY, Bureau des Longitudes, Paris, France; Prof. RuDOLF PESEK, Academy of Sciences, Prague, Czechoslovakia. The detailed ...

  20. Lightweight Ultrahigh Temperature CMC-Encased C/C Structure for Reentry and Hypersonic Applications, Phase II Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future reentry and hypersonic vehicles require advanced lightweight leading edge thermal protection systems that can provide the dual functionality of...

  1. Attitude-Control Algorithm for Minimizing Maneuver Execution Errors

    Science.gov (United States)

    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.

  2. Acute aortic thrombosis following incorrect application of the Heimlich maneuver.

    Science.gov (United States)

    Mack, Lloyd; Forbes, Thomas L; Harris, Kenneth A

    2002-01-01

    The Heimlich maneuver has been widely accepted as a safe and effective method of relieving life-threatening foreign-body upper airway obstruction. When applied incorrectly, however, it may result in direct trauma to the intraabdominal viscera. Only two cases of major aortic complications have been reported. Both have involved thrombosis of an abdominal aortic aneurysm. We report two further instances of aortic thrombotic complications due to the incorrect application of the Heimlich maneuver. The first case resulted in thrombosis of an abdominal aortic aneurysm. In the second case the abdominal thrusts caused dislodgement of thrombus from an atherosclerotic nonaneurysmal aorta, which resulted in thromboembolic occlusion of both lower extremities. In both cases, as with the two previously reported instances, massive reperfusion injury resulted, which eventually proved fatal. When applied incorrectly, the Heimlich maneuver may result in direct trauma to the abdominalaorta and is an unusual cause of acute aortic thrombosis.

  3. New therapeutic maneuver for anterior canal benign paroxysmal positional vertigo.

    Science.gov (United States)

    Yacovino, Dario A; Hain, Timothy C; Gualtieri, Francisco

    2009-11-01

    This article describes the clinical features of anterior semicircular canal benign paroxysmal positional vertigo (AC-BPPV) and a new therapeutic maneuver for its management. Our study was a retrospective review of cases from an ambulatory tertiary referral center. Thirteen patients afflicted with positional paroxysmal vertigo exhibiting brief positional down-beating nystagmus in positional tests (Dix-Hallpike and head-hanging position) were treated with a maneuver comprised of the following movements: Sequential head positioning beginning supine with head hanging 30 degrees dependent with respect to the body, then supine with head inclined 30 degrees forward, and ending sitting with head 30 degrees forward. All cases showed excellent therapeutic response to our repositioning procedure, i.e. relief of vertigo and elimination of nystagmus. The maneuver described is an option for AC-BPPV treatment.

  4. A new technique for calculating reentry base heating. [analysis of laminar base flow field of two dimensional reentry body

    Science.gov (United States)

    Meng, J. C. S.

    1973-01-01

    The laminar base flow field of a two-dimensional reentry body has been studied by Telenin's method. The flow domain was divided into strips along the x-axis, and the flow variations were represented by Lagrange interpolation polynomials in the transformed vertical coordinate. The complete Navier-Stokes equations were used in the near wake region, and the boundary layer equations were applied elsewhere. The boundary conditions consisted of the flat plate thermal boundary layer in the forebody region and the near wake profile in the downstream region. The resulting two-point boundary value problem of 33 ordinary differential equations was then solved by the multiple shooting method. The detailed flow field and thermal environment in the base region are presented in the form of temperature contours, Mach number contours, velocity vectors, pressure distributions, and heat transfer coefficients on the base surface. The maximum heating rate was found on the centerline, and the two-dimensional stagnation point flow solution was adquate to estimate the maximum heating rate so long as the local Reynolds number could be obtained.

  5. Variable structure guidance law for attacking surface maneuver targets

    Institute of Scientific and Technical Information of China (English)

    Han Yanhua; Xu Bo

    2008-01-01

    The characteristics of surface maneuver targets are analyzed and a 3-D relative motion model for missiles and targets is established. A variable structure guidance law is designed considering the characteristics of targets. In the guidance law, the distance between missiles and targets as well as the missile-target relative velocity are all substituted by estimation values. The estimation errors, the target's velocity, and the maneuver acceleration are all treated as bounded disturbance. The guidance law proposed can be implemented conveniently in engineering with little target information. The performance of the guidance system is analyzed theoretically and the numerical simulation result shows the effectiveness of the guidance law.

  6. Tracking of Maneuvering Target in Glint Noise Environment

    Institute of Scientific and Technical Information of China (English)

    ZUODongguang; BIANShutan; HANChongzhao; ZHENGLin; ZHUHongyan

    2005-01-01

    This paper presents a tracking algorithm for maneuvering target in the presence of glint noise. In radar target tracking system, because of the random wandering of the target position, the measurement noise is clearly non-Gaussian distribution, called as glint noise, which has a considerable influence on conventional linear estimates. In this paper, the glint noise is modeled via the mixture of Gaussian distribution and Laplace distribution, and tackled with two model sets. The tracking algorithm for maneuvering target is derived detailedly when the model sets is interacting in the presence of glint noise. The Monte Carlo simulation results express its better performance in comparison with the IMM algorithm.

  7. Traumatic rupture of the stomach secondary to Heimlich maneuver.

    Science.gov (United States)

    Dupre, M W; Silva, E; Brotman, S

    1993-11-01

    The case of a 93-year-old man who received a Heimlich maneuver while choking is reported. After the procedure, the patient presented with abdominal pain and ultimately was found to have developed a gastric rupture. He was hospitalized for 66 days. Review of the literature showed that only four gastric perforations related to the Heimlich maneuver have been documented. Other complications have occurred. It is reasonable to perform the procedure as an alternative to asphyxiation, but emergency physicians must be aware of the fact that life-threatening complications may ensue.

  8. Active Control of Solar Array Dynamics During Spacecraft Maneuvers

    Science.gov (United States)

    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.

  9. Autopilot Control Synthesis for Path Tracking Maneuvers of Underwater Vehicles

    Institute of Scientific and Technical Information of China (English)

    Sam-Sang YOU; Hyeung-Sik CHOI; Hwan-Seong KIM; Han-Il PARK

    2011-01-01

    This paper is concerned with the robust control synthesis of autonomous underwater vehicle (AUV) for general path following maneuvers. First, we present maneuvering kinematics and vehicle dynamics in a unified framework. Based on H loop-shaping procedure, the 2-DOF autopilot controller has been presented to enhance stability and path tracking.By use of model reduction, the high-order control system is reduced to one with reasonable order, and further the scaled low-order controller has been analyzed in both the frequency and the time domains. Finally, it is shown that the autopilot control system provides robust performance and stability against prescribed levels of uncertainty.

  10. Ongoing Capabilities and Developments of Re-Entry Plasma Ground Tests at EADS-ASTRIUM

    Science.gov (United States)

    Jullien, Pierre

    2008-01-01

    During re-entry, spacecrafts are subjected to extreme thermal loads. On mars, they may go through dust storms. These external heat loads are leading the design of re-entry vehicles or are affecting it for spacecraft facing solid propellant jet stream. Sizing the Thermal Protection System require a good knowledge of such solicitations and means to model and reproduce them on earth. Through its work on European projects, ASTRIUM has developed the full range of competences to deal with such issues. For instance, we have designed and tested the heat-shield of the Huygens probe which landed on Titan. In particular, our plasma generators aim to reproduce a wide variety of re-entry conditions. Heat loads are generated by the huge speed of the probes. Such conditions cannot be fully reproduced. Ground tests focus on reproducing local aerothermal loads by using slower but hotter flows. Our inductive plasma torch enables to test little samples at low TRL. Amongst the arc-jets, one was design to test architecture design of ISS crew return system and others fit more severe re-entry such as sample returns or Venus re-entry. The last developments aimed in testing samples in seeded flows. First step was to design and test the seeding device. Special diagnostics characterizing the resulting flow enabled us to fit it to the requirements.

  11. Acute thrombosis of abdominal aortic aneurysm subsequent to Heimlich maneuver: a case report.

    Science.gov (United States)

    Kirshner, R L; Green, R M

    1985-07-01

    We report a case of acute thrombosis of an abdominal aortic aneurysm secondary to a correctly applied and successful Heimlich maneuver. Although the Heimlich maneuver is generally safe and effective, this possible catastrophic consequence needs to be recognized.

  12. NOx production and rainout from Chicxulub impact ejecta reentry

    Science.gov (United States)

    Parkos, Devon; Alexeenko, Alina; Kulakhmetov, Marat; Johnson, Brandon C.; Melosh, H. Jay

    2015-12-01

    The Chicxulub impact 66.0 Ma ago initiated the second biggest extinction in the Phanerozoic Eon. The cause of the concurrent oceanic nitrogen isotopic anomaly, however, remains elusive. The Chicxulub impactor struck the Yucatán peninsula, ejecting 2 × 1015 kg of molten and vaporized rock that reentered globally as approximately 1023 microscopic spherules. Here we report that modern techniques indicate that this ejecta generates 1.5 × 1014 moles of NOx, which is enough to cause the observed nitrogen enrichment of the basal layer. Additionally, reentry-based NO production would explain the anomalously heavy isotopic composition of the observed nitrogen. We include N, O, N2, O2, and NO species in simulations of nonequilibrium chemically reacting flow around a reentering spherule. We then determine the net production of NO from all the spherules and use turbulence models to determine how quickly this yield diffuses through the atmosphere. Upon reaching the stratosphere and troposphere, cloud moisture absorbs the NOx and forms nitric acid. We model this process and determine the acidity of the resulting precipitation, which peaks about 1 year after the impact. The precipitation ultimately reaches the upper ocean, where we assume that the well-mixed surface layer is 100 m deep. We then model the naturally occurring carbonate/bicarbonate buffer and determine the net pH. We find that insufficient NOx reaches the ocean to directly cause the observed end-Cretaceous oceanic extinction via acidification and buffer removal. However, the resulting nitrates are sufficient to explain the concurrent nitrogen isotopic anomaly and facilitate an end-Cretaceous algae bloom.

  13. Acute abdominal aortic thrombosis following the Heimlich maneuver.

    Science.gov (United States)

    Ayerdi, Juan; Gupta, Sushil K; Sampson, Lawrence N; Deshmukh, Narayan

    2002-04-01

    Complications from the Heimlich maneuver are relatively infrequent. Two fatal cases of abdominal aortic thrombosis have been reported following this technique. We report on the first patient that suffered an acute thrombosis of the abdominal aorta and survived. Prompt recognition of this complication provides the only hope of survival from this rare and catastrophic complication.

  14. Heimlich's maneuver-assisted bronchoscopic removal of airway foreign body.

    Science.gov (United States)

    Solanki, Sohan Lal; Bansal, Shivendu; Khare, Arvind; Jain, Amit

    2011-01-01

    Aspiration of foreign bodies (FBs) by children can lead to serious illness and sometimes even death. Bronchoscopic removal of the FB is necessary to prevent from any catastrophic event. Sometimes bronchoscopic removal is not possible due to the larger size of the FB, sharp FB, or long duration FB. Tracheostomy is normally used for the removal of such FBs. The aim of this case report is to highlight the use of Heimlich maneuver for the removal of such FBs before opting invasive procedures. In the present case, a 5-year-old child was presented with history of FB aspiration 5 h back. After multiple failed bronchoscopic attempts to remove the FB it was decided to use Heimlich maneuver in the supine position. A single attempt of Heimlich maneuver expelled the FB into the oral cavity, which was removed by Magill's forceps. On repeated bronchoscope check, there was no remnant of FB. Child's further course of stay in hospital was uneventful. In conclusion, Heimlich maneuver may be useful in patient with failed bronchoscope removal of airway FBs before proceeding for tracheotomy or other invasive procedures.

  15. Ruptured aortic valve cusp: a complication of the Heimlich maneuver.

    Science.gov (United States)

    Chapman, J H; Menapace, F J; Howell, R R

    1983-07-01

    A case of traumatic rupture of the aortic valve as a complication of the Heimlich maneuver is presented. Conformation was made by comparative echocardiographic studies available from three months before and immediately following the incident. The patient refused surgical intervention and died one month later with severe congestive heart failure despite vigorous medical therapy.

  16. EOS Terra Terra Constellation Exit/Future Maneuver Plans Update

    Science.gov (United States)

    Mantziaras, Dimitrios

    2016-01-01

    This EOS Terra Constellation Exit/Future Maneuver Plans Update presentation will discuss brief history of Terra EOM work; lifetime fuel estimates; baseline vs. proposed plan origin; resultant exit orbit; baseline vs. proposed exit plan; long term orbit altitude; revised lifetime proposal and fallback options.

  17. Biologically inspired force enhancement for maritime propulsion and maneuvering

    CERN Document Server

    Weymouth, G D

    2016-01-01

    The move to high performance applications greatly increases the demand to produce large instantaneous fluid forces for high-speed maneuvering and improved power efficiency for sustained propulsion. Animals achieve remarkable feats of maneuvering and efficiency by changing their body shape to generate unsteady fluid forces. Inspired by this, we have studied a range of immersed bodies which drastically change their shape to produce fluid forces. These include relatively simple shape- changes, such as quickly changing the angle of attack of a foil to induce emergency stops and the use of tandem flapping foils to generate three times the average propulsive force of a single flapping foil. They also include more unconventional shape-changes such as high-speed retracting foil sections to power roll and dive maneuvers and the use of soft robotics to rapidly shrink the frontal area of an ellipsoid to power 68% efficient fast-start maneuvers or even completely cancel the drag force with 91% quasi-propulsive efficiency...

  18. Proposal for Global Standard Maneuvering Orders for Tugboats

    Directory of Open Access Journals (Sweden)

    Ayumi Ishikura

    2013-12-01

    Full Text Available The use of “Standard Maneuvering Orders” for tugboats, vocabulary and phrases mutually pre-agreed between ships and tugboats, is essential for the former to provide clear direction for the latter when berthing or un-berthing safely. Tugboats will need time to change their posture before they take actions in response to orders from persons responsible for ships’ maneuvering. Therefore, when giving directions to change tugboats’ posture, persons who handle their ships are required to send out tug orders, with regard to “delay time,” a gap be-tween the orders from ships and the actions taken by tugboats. “Tug Orders” standardized and used in Japan are composed of the following three factors concerning towage work: tugboat’s motion, direction and engine power, but the author’s research shows that there are “Non-standard” special maneuvering orders other than those “standardized,” which causes such problems as a gap in perception between pilots and tugboat’s opera-tors, etc. The purpose of this paper is to research the delay time between orders for and actions by tugboats and consider the appropriate and safe timing of providing instructions to them, and then to propose globally-authorized “Standard Maneuvering Orders for tugboats”, discussing a problem involved in the use of the special orders used in Japan, and the way in which tug orders are used in other countries.

  19. Time frequency analysis of sound from a maneuvering rotorcraft

    Science.gov (United States)

    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.

  20. Volunteer kinematics and reaction in lateral emergency maneuver tests

    NARCIS (Netherlands)

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

    2013-01-01

    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 s

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

    Science.gov (United States)

    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. 8 CFR 211.3 - Expiration of immigrant visas, reentry permits, refugee travel documents, and Form I-551.

    Science.gov (United States)

    2010-01-01

    ... permits, refugee travel documents, and Form I-551. 211.3 Section 211.3 Aliens and Nationality DEPARTMENT... Expiration of immigrant visas, reentry permits, refugee travel documents, and Form I-551. An immigrant visa, reentry permit, refugee travel document, or Form I-551 shall be regarded as unexpired if the...

  3. Campagne FARE: Wireline reentry of DSDP Hole 396B using the NADIA System

    Science.gov (United States)

    Legrand, Jacques; Echardour, André; Floc'h, Henri; Floury, Luc; Harmegnies, François; Loaec, Gerard; Raer, Yves; Stephen, Ralph; Gieskes, Joris; Pozzi, Jean-Pierre

    This paper describes the successful field test of the NADIA (Navette de Diagraphie, which means logging shuttle) wireline reentry system, an apparatus designed and built by IFREMER (Institut Francaise de Recherche pour l'Exploitation de la Mer) to place instruments and to carry out well logging in boreholes in the deep sea without a drill ship. The Campagne FARE (Faisabilite Re-Entree) field tests in July 1988 in DSDP (Deep Sea Drilling Project) Hole 396B (near the Kane Fracture Zone at the Mid-Atlantic Ridge (Figure 1)) demonstrated the feasibility of routine reentry and logging in a water depth of 4455 m.

  4. Prisoner reentry: a public health or public safety issue for social work practice?

    Science.gov (United States)

    Patterson, George T

    2013-01-01

    A significant literature identifies the policy, economic, health, and social challenges that confront released prisoners. This literature also describes the public health and public safety risks associated with prisoner reentry, provides recommendations for improving the reentry process, and describes the effectiveness of prison-based programs on recidivism rates. Public health and public safety risks are particularly significant in communities where large numbers of prisoners are released and few evidence-based services exist. The purpose of this article is to describe the public health and public safety risks that released prisoners experience when they reenter communities, and to discuss the social justice issues relevant for social work practice.

  5. Re-entry Attitude Double-loop SMC of the Spacecraft and Its Logic Selection

    Institute of Scientific and Technical Information of China (English)

    CHEN Yu-wen; BI Kai-bo

    2007-01-01

    A spacecraft re-entry attitude control method using sliding mode control (SMC) theory is developed. The controller utilizes double-loop SMC scheme and provides the robust, de-coupled tracking of both the angular velocity and the shuttle orientation angles. In accordance with the hybrid-controlling characteristics of the aerodynamic surfaces and reaction control system of the spacecraft, the control torque commands are allocated into the actuators such as the aerodynamic surfaces and reaction control system by using the optimal control selection allocation algorithm. The simulation of the spacecraft re-entry attitude controlling demonstrates the robust, de-coupled tracking performance of the proposed method and its validity.

  6. A New Concept for Atmospheric Reentry Optimal Guidance: An Inverse Problem Inspired Approach

    Directory of Open Access Journals (Sweden)

    Davood Abbasi

    2013-01-01

    Full Text Available This paper presents a new concept for atmospheric reentry online optimal guidance and control using a method called MARE G&C that exploits the different time scale featured by reentry dynamics. The new technique reaches a quasi-analytical solution and simplified computations, even considering both lift-to-drag ratio and aerodynamic roll as control variables; in addition, the paper offers a solution for the challenging path constraints issue, getting inspiration from the inverse problem methodology. The final resulting algorithm seems suitable for onboard predictive guidance, a new need for future space missions.

  7. Effect of surface catalycity on high-altitude aerothermodynamics of reentry vehicles

    Science.gov (United States)

    Molchanova, A. N.; Kashkovsky, A. V.; Bondar, Ye. A.

    2016-10-01

    This work is aimed at the development of surface chemistry models for the Direct Simulation Monte Carlo (DSMC) method applicable to non-equilibrium high-temperature flows about reentry vehicles. Probabilities of the surface processes dependent on individual properties of each particular molecule are determined from the macroscopic reaction rate data. Two different macroscopic finite rate sets are used for construction of DSMC surface recombination models. The models are implemented in the SMILE++ software system for DSMC computations. A comparison with available experimental data is performed. Effects of surface recombination on the aerothermodynamics of a blunt body at high-altitude reentry conditions are numerically studied with the DSMC method.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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.

  10. Development of a flight test maneuver autopilot for an F-15 aircraft

    Science.gov (United States)

    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. This paper presents the development of control laws for a flight test maneuver autopilot for an F-15 aircraft. A linear quadratic regulator approach is used to develop the control laws within the context of flight test maneuver requirements by treating the maneuver as a finite time tracking problem with regulation of state rates. Results are presented to show the effectiveness of the controller in insuring acceptable aircraft performance during a maneuver.

  11. An approximate atmospheric guidance law for aeroassisted plane change maneuvers

    Science.gov (United States)

    Speyer, Jason L.; Crues, Edwin Z.

    1988-01-01

    An approximate optimal guidance law for the aeroassisted plane change problem is presented which is based upon an expansion of the Hamilton-Jacobi-Bellman equation with respect to the small parameter of Breakwell et al. (1985). The present law maximizes the final velocity of the reentry vehicle while meeting terminal constraints on altitude, flight path angle, and heading angle. The integrable zeroth-order solution found when the small parameter is set to zero corresponds to a solution of the problem where the aerodynamic forces dominate the inertial forces. Higher order solutions in the expansion are obtained from the solution of linear partial differential equations requiring only quadrature integration.

  12. Mentoring Formerly Incarcerated Adults: Insights from the Ready4Work Reentry Initiative. Field Report Series

    Science.gov (United States)

    Bauldry, Shawn; Korom-Djakovic, Danijela; McClanahan, Wendy S.; McMaken, Jennifer; Kotloff, Lauren J.

    2009-01-01

    This report explores mentoring as a tool for supporting the successful reintegration of formerly incarcerated individuals within the context of a larger reentry strategy--in this case, the "Ready4Work" model. "Ready4Work" was a three-year national demonstration designed to address the needs of the growing ex-prisoner population and to test the…

  13. Exploring Efficacy in Negotiating Support: Women Re-Entry Students in Higher Education

    Science.gov (United States)

    Filipponi-Berardinelli, Josephine Oriana

    2013-01-01

    The existing literature on women re-entry students reveals that women students concurrently struggle with family, work, and sometimes health issues. Women students often do not receive adequate support from their partners or from other sources in helping manage the multiple roles that compete for their time, and often face constraints that affect…

  14. ENTRYSAT: A 3U Cubesat to Study the Re-Entry Atmospheric Environment

    Science.gov (United States)

    Garcia, R. F.; Chaix, J.; Mimoun, D.; EntrySat student Team

    2014-04-01

    The EntrySat is a 3U CubeSat designed to study the uncontrolled atmospheric re-entry. The project, developed by ISAE in collaboration with ONERA, is funded by CNES and is intended to be launched in January 2016, in the context of the QB50 network. The scientific goal is to relate the kinematics of the satellite with the aerothermodynamic environment during re-entry. In particular, data will be compared with the computations of MUSIC/FAST, a new 6-degree of freedom code developed by ONERA to predict the trajectory of space debris. According to these requirements, the satellite will measure the temperature, pressure, heat flux, and drag force during re-entry, as well as the trajectory and attitude of the satellite. One of the major technological challenges is the retrieval of data during the re-entry phase, which will be based on the Iridium satellite network. The system design is based on the use of commercial COTS components, and is mostly developed by students from ISAE. As such, the EntrySat has an important educational value in the formation of young engineers.

  15. Optimization of Observation Strategy to Improve Re-entry Prediction of Objects in HEO

    Science.gov (United States)

    Rasotto, M.; Di Mauro, G.; Massari, M.; Di Lizia, P.; Armellin, R.; Funke, Q.; Flohrer, T.

    2016-09-01

    During the last decade the number of space debris moving on high elliptical orbit (HEO) has grown fast. Many of these resident space objects (RSO) consist of medium and large spent upper stages of launch vehicles, whose atmosphere re-entry might violate on-ground casualty risk constraints. Increasing the accuracy of re-entry predictions for this class of RSO is therefore a key issue to limit the hazards on the Earth assets. Traditional computational methods are mainly based on the exploitation of Two Line Elements (TLEs), provided by the United States Strategic Command (USSTRATCOM) and currently the only public data source available for these kind of analyses. TLE data however, are characterized by low accuracies, and in general come without any uncertainty information, thus limiting the achievable precision of the re-entry estimates. Better results on the other hand, can be obtained through the exploitation of observational data provided by one or more Earth sensors. Despite the benefits, this approach introduces a whole new set of complexities, mainly related with the design of proper observation campaigns. This paper presents a method based on evolutionary algorithms, for the optimization of observation strategies. The effectiveness of the proposed approach is demonstrated through dedicated examples, in which re-entry predictions, attainable with existing and ideal sensor architectures, are compared with corresponding results derived from TLE data.

  16. Development of a Sheathed Miniature Aerothermal Reentry Thermocouple for Thermal Protection System Materials

    Science.gov (United States)

    Martinez, Edward R.; Weber, Carissa Tudryn; Oishi, Tomo; Santos, Jose; Mach, Joseph

    2011-01-01

    The Sheathed Miniature Aerothermal Reentry Thermocouple is a micro-miniature thermocouple for high temperature measurement in extreme environments. It is available for use in Thermal Protection System materials for ground testing and flight. This paper discusses the heritage, and design of the instrument. Experimental and analytical methods used to verify its performance and limitations are described.

  17. 75 FR 22813 - Guidance for Industry: Requalification Method for Reentry of Blood Donors Deferred Because of...

    Science.gov (United States)

    2010-04-30

    ...The Food and Drug Administration (FDA) is announcing the availability of a document entitled ``Guidance for Industry: Requalification Method for Reentry of Blood Donors Deferred Because of Reactive Test Results for Antibody to Hepatitis B Core Antigen (Anti- HBc),'' dated May 2010. The guidance document provides recommendations to establishments that collect Whole Blood or blood components......

  18. 77 FR 40068 - Draft Guidance for Industry: Recommendations for Donor Questioning, Deferral, Reentry, and...

    Science.gov (United States)

    2012-07-06

    ...The Food and Drug Administration (FDA) is announcing the availability of a draft guidance document entitled ``Guidance for Industry: Recommendations for Donor Questioning, Deferral, Reentry and Product Management to Reduce the Risk of Transfusion-Transmitted Malaria'' dated June 2012. The draft guidance document provides blood establishments that collect blood and blood components with......

  19. 78 FR 50421 - Guidance for Industry: Recommendations for Donor Questioning, Deferral, Reentry, and Product...

    Science.gov (United States)

    2013-08-19

    ...The Food and Drug Administration (FDA) is announcing the availability of a document entitled ``Guidance for Industry: Recommendations for Donor Questioning, Deferral, Reentry and Product Management to Reduce the Risk of Transfusion-Transmitted Malaria'' dated August 2013. The guidance document provides blood establishments that collect blood and blood components with recommendations for......

  20. From Corrections to Community: The Juvenile Reentry Experience as Characterized by Multiple Systems Involvement

    Science.gov (United States)

    Cusick, Gretchen Ruth; Goerge, Robert M.; Bell, Katie Claussen

    2009-01-01

    This Chapin Hall report describes findings on the extent of system involvement among Illinois youth released from correctional facilities, tracking a population of youth under age 18 in Illinois following their release. Using administrative records, researchers develop profiles of reentry experiences across the many systems that serve youth and…

  1. A synthetic environment for visualization and planning of orbital maneuvers

    Science.gov (United States)

    Ellis, Stephen R.; Grunwald, Arthur J.

    An interactive proximity operations planning system, which allows on-site planning of fuel-efficient, multi-burn maneuvers in a potential multi-space-craft environment has been developed and tested. This display system most directly assists planning by providing visual feedback in a synthetic virtual space that aids visualization of trajectories and their constraints. Its most significant features include (1) an 'inverse dynamics' algorithm that removes control nonlinearities facing the operator and (2) a stack-oriented action-editor that reduces the order of control and creates, through a 'geometric spreadsheet,' the illusion of an inertially stable environment. This synthetic environment provides the user with control of relevant static and dynamic properties of way-points during small orbital changes allowing independent solutions to otherwise coupled problems of orbital maneuvering.

  2. Single step optimization of manipulator maneuvers with variable structure control

    Science.gov (United States)

    Chen, N.; Dwyer, T. A. W., III

    1987-01-01

    One step ahead optimization has been recently proposed for spacecraft attitude maneuvers as well as for robot manipulator maneuvers. Such a technique yields a discrete time control algorithm implementable as a sequence of state-dependent, quadratic programming problems for acceleration optimization. Its sensitivity to model accuracy, for the required inversion of the system dynamics, is shown in this paper to be alleviated by a fast variable structure control correction, acting between the sampling intervals of the slow one step ahead discrete time acceleration command generation algorithm. The slow and fast looping concept chosen follows that recently proposed for optimal aiming strategies with variable structure control. Accelerations required by the VSC correction are reserved during the slow one step ahead command generation so that the ability to overshoot the sliding surface is guaranteed.

  3. Evasive Maneuvers in Space Debris Environment and Technological Parameters

    Directory of Open Access Journals (Sweden)

    Antônio D. C. Jesus

    2012-01-01

    Full Text Available We present a study of collisional dynamics between space debris and an operational vehicle in LEO. We adopted an approach based on the relative dynamics between the objects on a collisional course and with a short warning time and established a semianalytical solution for the final trajectories of these objects. Our results show that there are angular ranges in 3D, in addition to the initial conditions, that favor the collisions. These results allowed the investigation of a range of technological parameters for the spacecraft (e.g., fuel reserve that allow a safe evasive maneuver (e.g., time available for the maneuver. The numerical model was tested for different values of the impact velocity and relative distance between the approaching objects.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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).

  6. Novel Fractional Order Calculus Extended PN for Maneuvering Targets

    Directory of Open Access Journals (Sweden)

    Jikun Ye

    2017-01-01

    Full Text Available Based on the theory of fractional order calculus (FOC, a novel extended proportional guidance (EPN law for intercepting the maneuvering target is proposed. In the first part, considering the memory function and filter characteristic of FOC, the novel extended PN guidance algorithm is developed based on the conventional PN after introducing the properties and operation rules of FOC. Further, with the help of FOC theory, the average load and ballistics characteristics of proposed guidance law are analyzed. Then, using the small offset kinematic model, the robustness of the new guidance law against autopilot parameters is studied theoretically by analyzing the sensitivity of the closed loop guidance system. At last, representative numerical results show that the designed guidance law obtains a better performance than the traditional PN for maneuvering target.

  7. Differential Evolution Optimization for Targeting Spacecraft Maneuver Plans

    Science.gov (United States)

    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.

  8. Maintenance Maneuver Automation for an Adapted Cylindrical Shape TEC

    Directory of Open Access Journals (Sweden)

    Rafael Morales

    2016-09-01

    Full Text Available Several manufacturers have developed devices with which to harness tidal/current power in areas where the depth does not exceed 40 m. These are the so-called first generation Tidal Energy Converters (TEC, and they are usually fixed to the seabed by gravity. When carrying out maintenance tasks on these devices it is, therefore, necessary to remove the nacelles from their bases and raise them to the surface of the sea. They must subsequently be placed back on their bases. These tasks require special high performance ships, signifying high maintenance costs. The automation of emersion and immersion maneuvers will undoubtedly lead to lower costs, given that ships with less demanding requirements will be required for the aforementioned maintenance tasks. This research presents a simple two degrees of freedom dynamic model that can be used to control a first generation TEC that has been conceived of to harness energy from marine currents. The control of the system is carried out by means of a water ballast system located inside the nacelle of the main power unit and is used as an actuator to produce buoying vertical forces. A nonlinear control law based on a decoupling term for the closed loop depth and/or orientation control is also proposed in order to ensure adequate behavior when the TEC performs emersion and immersion maneuvers with only hydrostatic buoyancy forces. The control scheme is composed of an inner loop consisting of a linear and decoupled input/output relationship and the vector of friction and compressibility terms and an outer loop that operates with the tracking error vector in order to ensure the asymptotically exponential stability of the TEC posture. Finally, the effectiveness of the dynamic model and the controller approach is demonstrated by means of numerical simulations when the TEC is carrying out an emersion maneuver for the development of general maintenance tasks and an emersion maneuver for blade-cleaning maintenance

  9. Firepower, Maneuver, and the Operational Level of War

    Science.gov (United States)

    1992-05-15

    wasn’t." Field Marshal Bernard Law Montgomery and General George S. Patton, two of the premier Allied field commanders in the European Theater of...higher headquarters and grafted onto another. Moreover, such changes are detrimental in a moral sense to the espirit and comradeship that most soldiers...Operation Barbarossa s-emed to exemplify "distrtbuted free maneuver" with three non-supporting thrusts into the Soviet Union , and with freGuent

  10. Measuring Pilot Proficiency on an Instrument Training Maneuver

    Science.gov (United States)

    1977-08-01

    featmr• of the Advanced Simulator for Pilot Training ( ASPT ) could be suc- cess tuj ly used to facilitate the development and validation of a recording...for the instrument training maneuver Vertical S-A in which the unique record/playback features of the Advanced Simulator for Pilot Training ( ASPT ) were...the ASPT revealed several format and observe--workload problems that needed correction. SFollowing revision, the booklet (Appendix A) was given a

  11. Computing and Visualizing Reachable Volumes for Maneuvering Satellites

    Science.gov (United States)

    2011-09-01

    Computing and Visualizing Reachable Volumes for Maneuvering Satellites Ming Jiang, Willem H. de Vries, Alexander J. Pertica , Scot S. Olivier...Handbook. Elsevier, 2004. 6. M. Jiang, M. Andereck, A. J. Pertica , and S. S. Olivier. A Scalable Visualization System for Improving Space Situational...Jiang, J. Leek, J. L. Levatin, S. Nikolaev, A. J. Pertica , D. W. Phillion, H. K. Springer, and W. H. de Vries. High-Performance Computer Modeling of

  12. Vehicle Optimal Velocity Curves for Minimum-Time Maneuver

    Directory of Open Access Journals (Sweden)

    Li-xia Zhang

    2014-02-01

    Full Text Available A problem in vehicle minimum-time maneuver is the assumption that a vehicle passes through a given path in a minimal amount of time without deviating from the boundary of the given path. Vehicle handling inverse dynamics provides a new perspective to solve such problem. Based on inverse dynamics, this paper transformed the problem of optimal vehicle velocity for minimum-time maneuver into that of optimal control with the objective function of minimum time. The path for minimum vehicle travel time and the optimal control model were established. The optimal velocity curves for three types of paths, namely, monotonically increasing path, monotonically decreasing path, and constant radius path, were analyzed. On this basis, the optimal velocity curves were solved for two kinds of concrete paths: a path of decreasing curvature radius followed by a path of increasing curvature radius and another path of increasing curvature radius followed by a path of decreasing curvature radius. Nine cases of possible optimal velocity curves were acquired. The optimal velocity curve of the given path, that is, a parabola followed by a semicircle, was obtained. Optimal velocity curves can be used as reference for vehicle minimum-time maneuver, which is an important issue for driver safety in fast-moving vehicles.

  13. Missile-Borne SAR Raw Signal Simulation for Maneuvering Target

    Directory of Open Access Journals (Sweden)

    Weijie Xia

    2016-01-01

    Full Text Available SAR raw signal simulation under the case of maneuver and high-speed has been a challenging and urgent work recently. In this paper, a new method based on one-dimensional fast Fourier transform (1DFFT algorithm is presented for raw signal simulation of maneuvering target for missile-borne SAR. Firstly, SAR time-domain raw signal model is given and an effective Range Frequency Azimuth Time (RFAT algorithm based on 1DFFT is derived. In this algorithm, the “Stop and Go” (SaG model is adopted and the wide radar scattering characteristic of target is taken into account. Furthermore, the “Inner Pulse Motion” (IPM model is employed to deal with high-speed case. This new RFAT method can handle the maneuvering cases, high-speed cases, and bistatic radar cases, which are all possible in the missile-borne SAR. Besides, this raw signal simulation adopts the electromagnetic scattering calculation so that we do not need a scattering rate distribution map as the simulation input. Thus, the multiple electromagnetic reflections can be considered. Simulation examples prove the effectiveness of our method.

  14. ALGORITHMS FOR TRACKING MANEUVERING TARGET WITH PHASED ARRAY RADAR

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Several typical algorithms for tracking maneuvering target with phased array radar are studied in this paper. The constant gain filter with multiple models is analyzed. A typical method for adaptively controlling the sampling interval is modified. The performance of the single model and multiple model estimator with uniform and variable sampling interval are evaluated and compared. It is shown by the simulation results that it is necessary to apply the adaptive sampling policy based on the multiple model method when the maneuvering targets are tracked by the phased array radar since saving radar resources is more important. The adaptive algorithms of variable sampling interval are better than the algorithms of variable model. The adaptive policy to determine the sampling interval based on multiple model are superior than those based on the single-model filter, because IMM estimator can adapt to the maneuver more quickly and the prediction covariance of IMM is the more sensitive and more reliable index than residual to determine the sampling interval. With IMM-based method, lower sampling interval is required for a certain accuracy.

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

    Science.gov (United States)

    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.

  16. "Spaghetti Maneuver": A useful tool in pediatric laparoscopy - Our experience

    Directory of Open Access Journals (Sweden)

    Antonio Marte

    2011-01-01

    Full Text Available Aims: The laparoscopic "Spaghetti Maneuver" consists in holding an organ by its extremity with a grasper and rolling it up around the tool to keep the organ stable and facilitate its traction within a small space. We describe our experience with the "Spaghetti Maneuver" in some minimally invasive procedures. Materials and Methods: We successfully adopted this technique in 13 patients (5F : 8M aged between 6 and 14 years (average age, 10 on whom we performed 7 appendectomies, 2 ureteral reimplantation and 4 cholecystectomies. In all cases, after the first steps, the appendix, the gallbladder and the ureter were rolled around the grasper and easily isolated; hemostasis was thus induced and the organ was mobilized until removal during cholecystectomy and appendectomy, and before the reimplantation in case of ureteral reimplantation. Results: We found that this technique facilitated significantly the acts of holding, isolating and removing, when necessary, the structures involved, which remained constantly within the visual field of the operator. This allowed a very ergonomic work setting, overcoming the problem of the "blind" zone, which represents a dangerous and invisible area out of the operator′s control during laparoscopy. Moreover the isolation maneuvers resulted easier and reduced operating time. Conclusion: We think that this technique is easy to perform and very useful, because it facilitates the dissection of these organs, by harmonizing and stabilizing the force of traction exercised.

  17. Actuator characterization of a man-portable precision maneuver concept

    Institute of Scientific and Technical Information of China (English)

    Ilmars CELMINS; Frank E.FRESCONI; Bryant P.NELSON

    2014-01-01

    The US Army Research Laboratory is conducting research to explore technologies that may be suitable for maneuvering man-portable munitions. Current research is focused on the use of rotary actuators with spin-stabilized munitions. A rotary actuator holds the potential of providing a low-power solution for guidance of a spinning projectile. This is in contrast to a linear (reciprocating) actuator which would need to constantly change direction, resulting in large accelerations which in turn would require large forces, thereby driving up the actuator power. A rotational actuator would be operating at a fairly constant rotation rate once it is up to speed, resulting in much lower power requirements. Actuator experiments conducted over a variety of conditions validate the dynamic models of the actuator and supply the data necessary for model parameter estimation. Actuator performance metrics of spin rate response, friction, and power requirements were derived from the data. This study indicates that this class of maneuver concepts can be driven with these actuators. These results enable actuator design and multi-disciplinary simulation of refined maneuver concepts for a specific application.

  18. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    Science.gov (United States)

    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.

  19. Using the Heimlich maneuver to save near-drowning victims.

    Science.gov (United States)

    Heimlich, H J; Patrick, E A

    1988-08-01

    Flooding of the lungs occurs routinely in drowning victims. The cause of death in 90% of them is hypoxemia caused by water in the lungs. Mouth-to-mouth ventilation is ineffective until the water is removed. The Heimlich maneuver expels aspirated water, vomitus, debris, and other foreign matter. In treating near-drowning victims, place the victim in the supine position with head turned to the side and perform the Heimlich maneuver to evacuate water from the lungs, unless you know water is not in the respiratory tract. The Heimlich maneuver is a form of artificial respiration. It elevates the diaphragm, increasing intrathoracic pressure and compressing the lungs, and should be performed intermittently until all water is expelled. It is an especially useful technique because fear of contagion sometimes deters rescuers from using mouth-to-mouth ventilation . Further treatment has not been necessary in most instances. If the victim does not recover after water ceases to flow from the mouth, ventilation techniques, cardiopulmonary resuscitation, and other measures as indicated should be used.

  20. An Autonomous Onboard Targeting Algorithm Using Finite Thrust Maneuvers

    Science.gov (United States)

    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.

  1. Development of NVG test maneuvers for civilian aircraft

    Science.gov (United States)

    Jennings, Sion; Craig, Greg; Carignan, Stephan; Fischer, Heiko; Brulotte, Michel

    2008-04-01

    This document provides an overview of helicopter flight-test methods used to evaluate night vision goggles at the National Research Council of Canada's Institute for Aerospace Research. These techniques have been used to examine the performance of display systems in actual field conditions. The flight evaluations were based, in large part, on standard flight test maneuvers and rating systems outlined in Aeronautical Design Standard ADS-33. The document describes NVG test maneuvers developed from ADS-33 principles, including a high hover, a mirror C, a vertical descent, a parallel lateral translation, a turn about the tail, a confined area staged landing, a brown-out/white-out simulation and a lit pirouette. The overview also comprises a description of methods for controlling the cueing environment. These methods include an appropriate selection of maneuvers as well as devices for limiting pilot vision such as goggles with filters and apertures, and other devices. The paper concludes with a short discussion on the merits of developing accurate in-flight tests capable of resolving performance differences among displays.

  2. Variable structure attitude maneuver and vibration control of flexible spacecraft

    Institute of Scientific and Technical Information of China (English)

    HU Qing-lei; MA Cuang-fu

    2008-01-01

    A dual-stage control system design method is presented for the three-axis-rotational maneuver and vibration stabilization of a spacecraft with flexible appendages embedded with piezoceramics as sensor and actuator.In this design approach,the attitude control and the vibration suppression sub-systems ale designed separately using the lower order model.The design of attitude controller is based on the variable structure control (VSC)theory leading to a discontinuous control law.This controller accomplishes asymptotic attitude maneuvering in the closed-loop system and is insensitive to the interaction of elastic modes and uncertainty in the system.To actively suppress the flexible vibrations,the modal velocity feedback control method is presented by using piezoelectric materials as additional sensor and actuator bonded on the surface of the flexible appendages.In addition,a special configuration of actuators for three-axis attitude control is also investigated:the pitch attitude controlled by a momentum wheel,and the roll/yaw control achieved by on-off thrustem.which is modulated by pulse width pulse frequency modulation technique to construct the proper control torque history.Numerical simulations performed show that the rotational maneuver and vibration suppression ale accomplished in spite of the presence of disturbance torque and parameter uncertainty.

  3. Actuator characterization of a man-portable precision maneuver concept

    Directory of Open Access Journals (Sweden)

    Ilmars Celmins

    2014-06-01

    Full Text Available The US Army Research Laboratory is conducting research to explore technologies that may be suitable for maneuvering man-portable munitions. Current research is focused on the use of rotary actuators with spin-stabilized munitions. A rotary actuator holds the potential of providing a low-power solution for guidance of a spinning projectile. This is in contrast to a linear (reciprocating actuator which would need to constantly change direction, resulting in large accelerations which in turn would require large forces, thereby driving up the actuator power. A rotational actuator would be operating at a fairly constant rotation rate once it is up to speed, resulting in much lower power requirements. Actuator experiments conducted over a variety of conditions validate the dynamic models of the actuator and supply the data necessary for model parameter estimation. Actuator performance metrics of spin rate response, friction, and power requirements were derived from the data. This study indicates that this class of maneuver concepts can be driven with these actuators. These results enable actuator design and multi-disciplinary simulation of refined maneuver concepts for a specific application.

  4. Acute amiodarone promotes drift and early termination of spiral wave re-entry.

    Science.gov (United States)

    Nakagawa, Harumichi; Honjo, Haruo; Ishiguro, Yuko S; Yamazaki, Masatoshi; Okuno, Yusuke; Harada, Masahide; Takanari, Hiroki; Sakuma, Ichiro; Kamiya, Kaichiro; Kodama, Itsuo

    2010-07-01

    Intravenous application of amiodarone is commonly used in the treatment of life-threatening arrhythmias, but the underlying mechanism is not fully understood. The purpose of the present study is to investigate the acute effects of amiodarone on spiral wave (SW) re-entry, the primary organization machinery of ventricular tachycardia/fibrillation (VT/VF), in comparison with lidocaine. A two-dimensional ventricular myocardial layer was obtained from 24 Langendorff-perfused rabbit hearts, and epicardial excitations were analyzed by high-resolution optical mapping. During basic stimulation, amiodarone (5 microM) caused prolongation of action potential duration (APD) by 5.6%-9.1%, whereas lidocaine (15 microM) caused APD shortening by 5.0%-6.4%. Amiodarone and lidocaine reduced conduction velocity similarly. Ventricular tachycardias induced by DC stimulation in the presence of amiodarone were of shorter duration (sustained-VTs >30 s/total VTs: 2/58, amiodarone vs 13/52, control), whereas those with lidocaine were of longer duration (22/73, lidocaine vs 14/58, control). Amiodarone caused prolongation of VT cycle length and destabilization of SW re-entry, which is characterized by marked prolongation of functional block lines, frequent wavefront-tail interactions near the rotation center, and considerable drift, leading to its early annihilation via collision with anatomical boundaries. Spiral wave re-entry in the presence of lidocaine was more stabilized than in control. In the anisotropic ventricular myocardium, amiodarone destabilizes SW re-entry facilitating its early termination. Lidocaine, in contrast, stabilizes SW re-entry resulting in its persistence.

  5. Targeting of cytosolic phospholipase A2α impedes cell cycle re-entry of quiescent prostate cancer cells.

    Science.gov (United States)

    Yao, Mu; Xie, Chanlu; Kiang, Mei-Yee; Teng, Ying; Harman, David; Tiffen, Jessamy; Wang, Qian; Sved, Paul; Bao, Shisan; Witting, Paul; Holst, Jeff; Dong, Qihan

    2015-10-27

    Cell cycle re-entry of quiescent cancer cells has been proposed to be involved in cancer progression and recurrence. Cytosolic phospholipase A2α (cPLA2α) is an enzyme that hydrolyzes membrane glycerophospholipids to release arachidonic acid and lysophospholipids that are implicated in cancer cell proliferation. The aim of this study was to determine the role of cPLA2α in cell cycle re-entry of quiescent prostate cancer cells. When PC-3 and LNCaP cells were rendered to a quiescent state, the active form of cPLA2α with a phosphorylation at Ser505 was lower compared to their proliferating state. Conversely, the phospho-cPLA2α levels were resurgent during the induction of cell cycle re-entry. Pharmacological inhibition of cPLA2α with Efipladib upon induction of cell cycle re-entry inhibited the re-entry process, as manifested by refrained DNA synthesis, persistent high proportion of cells in G0/G1 and low percentage of cells in S and G2/M phases, together with a stagnant recovery of Ki-67 expression. Simultaneously, Efipladib prohibited the emergence of Skp2 while maintained p27 at a high level in the nuclear compartment during cell cycle re-entry. Inhibition of cPLA2α also prevented an accumulation of cyclin D1/CDK4, cyclin E/CDK2, phospho-pRb, pre-replicative complex proteins CDC6, MCM7, ORC6 and DNA synthesis-related protein PCNA during induction of cell cycle re-entry. Moreover, a pre-treatment of the prostate cancer cells with Efipladib during induction of cell cycle re-entry subsequently compromised their tumorigenic capacity in vivo. Hence, cPLA2α plays an important role in cell cycle re-entry by quiescent prostate cancer cells.

  6. Sensitivity analysis and probabilistic re-entry modeling for debris using high dimensional model representation based uncertainty treatment

    Science.gov (United States)

    Mehta, Piyush M.; Kubicek, Martin; Minisci, Edmondo; Vasile, Massimiliano

    2017-01-01

    Well-known tools developed for satellite and debris re-entry perform break-up and trajectory simulations in a deterministic sense and do not perform any uncertainty treatment. The treatment of uncertainties associated with the re-entry of a space object requires a probabilistic approach. A Monte Carlo campaign is the intuitive approach to performing a probabilistic analysis, however, it is computationally very expensive. In this work, we use a recently developed approach based on a new derivation of the high dimensional model representation method for implementing a computationally efficient probabilistic analysis approach for re-entry. Both aleatoric and epistemic uncertainties that affect aerodynamic trajectory and ground impact location are considered. The method is applicable to both controlled and un-controlled re-entry scenarios. The resulting ground impact distributions are far from the typically used Gaussian or ellipsoid distributions.

  7. Orbital Maneuvers Using Low Thrust to Place a Satellite in a Constellation

    Directory of Open Access Journals (Sweden)

    Vivian Martins Gomes

    2007-01-01

    Full Text Available This paper considers the problem of low thrust suboptimal maneuvers to insert a satellite in a constellation. It is assumed that a satellite constellation is given with all the Keplerian elements of the satellite members having known values. Then, it is necessary to maneuver a new satellite from a parking orbit to its position in the constellation. The control available to perform this maneuver is the application of a low thrust to the satellite and the objective is to perform this maneuver with minimum fuel consumption.

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

    Science.gov (United States)

    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.

  9. Command shaping for residual vibration free crane maneuvers

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  11. Simulation of upwind maneuvering of a sailing yacht

    Science.gov (United States)

    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

  12. Computing and Visualizing Reachable Volumes for Maneuvering Satellites

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  14. Heimlich's maneuver-assisted bronchoscopic removal of airway foreign body

    OpenAIRE

    Solanki, Sohan Lal; Bansal, Shivendu; Khare, Arvind; Jain, Amit

    2011-01-01

    Aspiration of foreign bodies (FBs) by children can lead to serious illness and sometimes even death. Bronchoscopic removal of the FB is necessary to prevent from any catastrophic event. Sometimes bronchoscopic removal is not possible due to the larger size of the FB, sharp FB, or long duration FB. Tracheostomy is normally used for the removal of such FBs. The aim of this case report is to highlight the use of Heimlich maneuver for the removal of such FBs before opting invasive procedures. In ...

  15. Robust control for snake maneuver design of missile

    Science.gov (United States)

    Kun, Ya; Chen, Xin; Li, Chuntao

    2017-01-01

    For the performance of missile with high Mach number and strongly nonlinear dynamics, this paper uses robust control to design maneuver controller. Robust servomechanism linear quadratic regulator (RSLQR) control is used to form the inner loop and proportional-plus-integral (PI) control is used to provide yawing tracking with no error. Contrast simulations under three types of deviation have been done to confirm robustness of the RSLQR-plus-PI control. Simulation results shows that RSLQR-plus-PI control would resist the disturbance and maintain the properties of the controller, guarantee the robustness and stability of missile more effectively than pure PI control.

  16. NONLINEAR DYNAMICS OF A CRACKED ROTOR IN A MANEUVERING AIRCRAFT

    Institute of Scientific and Technical Information of China (English)

    LIN Fu-sheng 林富生; MENG Guang 孟光; Eric Hahn

    2004-01-01

    The nonlinear dynamics of a cracked rotor system in an aircraft maneuvering with constant velocity or acceleration was investigated. The influence of the aircraft climbing angle on the cracked rotor system response is of particular interest and the results show that the climbing angle can markedly affect the parameter range for bifurcation, for quasi-periodic response and for chaotic response as well as for system stability. Aircraft acceleration is also shown to significantly affect the nonlinear behavior of the cracked rotor system, illustrating the possibility for on-line rotor crack fault diagnosis.

  17. OTHR Spectrum Reconstruction of Maneuvering Target with Compressive Sensing

    Directory of Open Access Journals (Sweden)

    Yinghui Quan

    2014-01-01

    Full Text Available High-frequency (HF over-the-horizon radar (OTHR works in a very complicated electromagnetic environment. It usually suffers performance degradation caused by transient interference. In this paper, we study the transient interference excision and full spectrum reconstruction of maneuvering targets. The segmental subspace projection (SP approach is applied to suppress the clutter and locate the transient interference. After interference excision, the spectrum is reconstructed from incomplete measurements via compressive sensing (CS by using a redundant Fourier-chirp dictionary. An improved orthogonal matching pursuit (IOMP algorithm is developed to solve the sparse decomposition optimization. Experimental results demonstrate the effectiveness of the proposed methods.

  18. Maneuvering Vehicle Tracking Based on Multi-sensor Fusion

    Institute of Scientific and Technical Information of China (English)

    CHENYing; HANChong-Zhao

    2005-01-01

    Maneuvering targets tracking is a fundamental task in intelligent vehicle research. This paper focuses on the problem of fusion between radar and image sensors in targets tracking. In order to improve positioning accuracy and narrow down the image working area, a novel method that integrates radar filter with image intensity is proposed to establish an adaptive vision window.A weighted Hausdorff distance is introduced to define the functional relationship between image and model projection, and a modified simulated annealing algorithm is used to find optimum orientation parameter. Furthermore, the global state is estimated, which refers to the distributed data fusion algorithm. Experiment results show that our method is accurate.

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

    Science.gov (United States)

    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

  20. Improving aggregate behavior in parking lots with appropriate local maneuvers

    KAUST Repository

    Rodriguez, Samuel

    2013-11-01

    In this paper we study the ingress and egress of pedestrians and vehicles in a parking lot. We show how local maneuvers executed by agents permit them to create trajectories in constrained environments, and to resolve the deadlocks between them in mixed-flow scenarios. We utilize a roadmap-based approach which allows us to map complex environments and generate heuristic local paths that are feasible for both pedestrians and vehicles. Finally, we examine the effect that some agent-behavioral parameters have on parking lot ingress and egress. © 2013 IEEE.

  1. Sequential Probability Ratio Test for Collision Avoidance Maneuver Decisions

    Science.gov (United States)

    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

  2. The Orbital Maneuvering Vehicle Training Facility visual system concept

    Science.gov (United States)

    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.

  3. Reentry Near the Percolation Threshold in a Heterogeneous Discrete Model for Cardiac Tissue

    Science.gov (United States)

    Alonso, Sergio; Bär, Markus

    2013-04-01

    Arrhythmias in cardiac tissue are related to irregular electrical wave propagation in the heart. Cardiac tissue is formed by a discrete cell network, which is often heterogeneous. A localized region with a fraction of nonconducting links surrounded by homogeneous conducting tissue can become a source of reentry and ectopic beats. Extensive simulations in a discrete model of cardiac tissue show that a wave crossing a heterogeneous region of cardiac tissue can disintegrate into irregular patterns, provided the fraction of nonconducting links is close to the percolation threshold of the cell network. The dependence of the reentry probability on this fraction, the system size, and the degree of excitability can be inferred from the size distribution of nonconducting clusters near the percolation threshold.

  4. Facilitation of school re-entry and peer acceptance of children with cancer

    DEFF Research Database (Denmark)

    Helms, Anne Sofie; Schmiegelow, K; Brok, J

    2016-01-01

    Increased survival rates from childhood cancer call for efforts to reintegrate children with cancer back into their academic and social environments. The aims of this study were to: (1) review and analyse the existing literature on school re-entry interventions for children with cancer; and (2......) discuss the importance of peer involvement in the treatment. Relevant databases were searched using equivalent search algorithms and six studies were selected that target children with cancer and/or their classmates. Two authors independently reviewed the literature for data extraction. The articles were...... reviewed using the PRISMA model for reporting reviews. Statistical calculations for the meta-analyses were done using Review Manager 5.2. The meta-analyses showed significant effects of school re-entry programmes in terms of enhancing academic achievement in children with cancer (P = 0.008) and lowering...

  5. Effect of shock interactions on the attitude stability of a toroidal ballute for reentry vehicles

    Science.gov (United States)

    Otsu, Hirotaka; Abe, Takashi

    2016-11-01

    The effect of shock interactions on the attitude stability of a reentry vehicle system with a toroidal ballute was investigated. The hypersonic wind tunnel experimental results showed that when the shock interaction occurred near or outside the ballute, an unstable oscillation of the ballute was observed. This was caused by the local high-pressure region on the ballute surface created by the shock interaction between the shock from the reentry capsule and the shock from the ballute. To avoid this unstable oscillation, the radius of the ballute should be designed to be large enough so that the shock from the capsule will be located inside the ballute, which can avoid the local high-pressure region on the ballute surface.

  6. Death, dynamics and disorder: Terminating reentry in excitable media by dynamically-induced inhomogeneities

    Indian Academy of Sciences (India)

    Johannes Breur; Sitabhra Sinha

    2005-04-01

    Formation of feedback loops of excitation waves (reentrant circuit) around non-conducting ventricular scar tissue is a common cause of cardiac arrhythmias, such as ventricular tachycardia, often leading to death. This is typically treated by rapid stimulation from an implantable device (ICD). However, the mechanisms of reentry termination success and, more importantly, failure, are poorly understood. To study such mechanisms, we simulated pacing termination of reentry in a model of cardiac tissue having significant restitution and dispersion properties. Our results show that rapid pacing dynamically generates conduction inhomogeneities in the reentrant circuit, leading to successful pacing termination of tachycardia. The study suggests that more effective pacing algorithms can be designed by taking into account the role of such dynamical inhomogeneities.

  7. Optimal guidance for reentry vehicles based on indirect Legendre pseudospectral method

    Science.gov (United States)

    Tian, Bailing; Zong, Qun

    2011-04-01

    Development of a feasible guidance scheme for reentry vehicles is a challenge because of its significant nonlinearity and multi-constraints. A method for the implementation of three-degree-of-freedom guidance for constrained reentry vehicle is presented in the paper. First, the constrained trajectory is generated by Legendre pseudospectral method (LPM) and then the feasibily of the trajectory is validated. Based on the obtained reference trajectory, the guidance problem is converted into a trajectory state regulation problem which is a linear time varying system. A robust state feedback guidance law is generated in real time using indirect Legendre pseudospectral feedback method. Finally, simulation results illustrate that the overall guidance scheme can lead to a very accurately controlled flight with all the constraints satisfied even in the presence of initial state uncertainty.

  8. Geometric analysis on the unidirectionality of the pulmonary veins for atrial reentry

    CERN Document Server

    Chun, Sehun

    2013-01-01

    It is widely believed that the pulmonary veins (PVs) of the atrium play the central role in the generation of atrial reentry leading to atrial fibrillation, but its mechanism has not been analytically explained. In order to improve the current clinical procedures for atrial reentry by understanding its mechanism, geometrical analysis is proposed on the conditions of conduction failure at the PVs and is validated by various computational modeling. To achieve this, a new analytic approach is proposed by adapting the geometric relative acceleration analysis from spacetime physics on the hypothesis that a large relative acceleration can translate to a dramatic increase in the curvature of the wavefront and subsequently to conduction failure. This analytic method is applied to a simplified model of the PV to reveal the strong dependency of the propagational direction and the magnitude of anisotropy for conduction failure. The unidirectionality of the PVs follows directly and is validated by computational tests in ...

  9. Advanced validation of CFD-FDTD combined method using highly applicable solver for reentry blackout prediction

    OpenAIRE

    Takahashi, Yusuke

    2015-01-01

    An analysis model of plasma flow and electromagnetic waves around a reentry vehicle for radio frequency blackout prediction during aerodynamic heating was developed in this study. The model was validated based on experimental results from the radio attenuation measurement program. The plasma flow properties, such as electron number density, in the shock layer and wake region were obtained using a newly developed unstructured grid solver that incorporated real gas effect models ...

  10. A national survey of 'inactive' physicians in the United States of America: enticements to reentry

    Directory of Open Access Journals (Sweden)

    Brotherton Sarah E

    2011-02-01

    Full Text Available Abstract Background Physicians leaving and reentering clinical practice can have significant medical workforce implications. We surveyed inactive physicians younger than typical retirement age to determine their reasons for clinical inactivity and what barriers, real or perceived, there were to reentry into the medical workforce. Methods A random sample of 4975 inactive physicians aged under 65 years was drawn from the Physician Masterfile of the American Medical Association in 2008. Physicians were mailed a survey about activity in medicine and perceived barriers to reentry. Chi-square statistics were used for significance tests of the association between categorical variables and t-tests were used to test differences between means. Results Our adjusted response rate was 36.1%. Respondents were fully retired (37.5%, not currently active in medicine (43.0% or now active (reentered, 19.4%. Nearly half (49.5% were in or had practiced primary care. Personal health was the top reason for leaving for fully retired physicians (37.8% or those not currently active in medicine (37.8% and the second highest reason for physicians who had reentered (28.8%. For reentered (47.8% and inactive (51.5% physicians, the primary reason for returning or considering returning to practice was the availability of part-time work or flexible scheduling. Retired and currently inactive physicians used similar strategies to explore reentry, and 83% of both groups thought it would be difficult; among those who had reentered practice, 35.9% reported it was difficult to reenter. Retraining was uncommon for this group (37.5%. Conclusion Availability of part-time work and flexible scheduling have a strong influence on decisions to leave or reenter clinical practice. Lack of retraining before reentry raises questions about patient safety and the clinical competence of reentered physicians.

  11. Functional reentry and circus movement arrhythmias in the small intestine of normal and diabetic rats.

    Science.gov (United States)

    Lammers, Wim J E P; Stephen, B; Karam, S M

    2012-04-01

    In a few recent studies, the presence of arrhythmias based on reentry and circus movement of the slow wave have been shown to occur in normal and diseased stomachs. To date, however, reentry has not been demonstrated before in any other part of the gastrointestinal system. No animals had to be killed for this study. Use was made of materials obtained during the course of another study in which 11 rats were treated with streptozotocin and housed with age-matched controls. After 3 and 7 mo, segments of duodenum, jejunum, and ileum were isolated and positioned in a tissue bath. Slow wave propagation was recorded with 121 extracellular electrodes. After the experiment, the propagation of the slow waves was reconstructed. In 10 of a total of 66 intestinal segments (15%), a circus movement of the slow wave was detected. These reentries were seen in control (n = 2) as well as in 3-mo (n = 2) and 7-mo (n = 6) diabetic rats. Local conduction velocities and beat-to-beat intervals during the reentries were measured (0.42 ± 0.15 and 3.03 ± 0.67 cm/s, respectively) leading to a wavelength of 1.3 ± 0.5 cm and a circuit diameter of 4.1 ± 1.5 mm. This is the first demonstration of a reentrant arrhythmia in the small intestine of control and diabetic rats. Calculations of the size of the circuits indicate that they are small enough to fit inside the intestinal wall. Extrapolation based on measured velocities and rates indicate that reentrant arrhythmias are also possible in the distal small intestine of larger animals including humans.

  12. Finite-Time Reentry Attitude Control Using Time-Varying Sliding Mode and Disturbance Observer

    OpenAIRE

    Xuzhong Wu; Shengjing Tang; Jie Guo; Yao Zhang

    2015-01-01

    This paper presents the finite-time attitude control problem for reentry vehicle with redundant actuators in consideration of planet uncertainties and external disturbances. Firstly, feedback linearization technique is used to cancel the nonlinearities of equations of motion to construct a basic mode for attitude controller. Secondly, two kinds of time-varying sliding mode control methods with disturbance observer are integrated with the basic mode in order to enhance the control performance ...

  13. Analytical Predictions of Thermal Stress in the Stardust PICA Heatshield Under Reentry Flight Conditions

    Science.gov (United States)

    Squire, Thomas; Milos, Frank; Agrawal, Parul

    2009-01-01

    We performed finite element analyses on a model of the Phenolic Impregnated Carbon Ablator (PICA) heatshield from the Stardust sample return capsule (SRC) to predict the thermal stresses in the PICA material during reentry. The heatshield on the Stardust SRC was a 0.83 m sphere cone, fabricated from a single piece of 5.82 cm-thick PICA. The heatshield performed successfully during Earth reentry of the SRC in January 2006. Material response analyses of the full, axisymmetric PICA heatshield were run using the Two-Dimensional Implicit Ablation, Pyrolysis, and Thermal Response Program (TITAN). Peak surface temperatures were predicted to be 3385K, while the temperature at the PICA backface remained at the estimated initial cold-soak temperature of 278K. Surface recession and temperature distribution results from TITAN, at several points in the reentry trajectory, were mapped onto an axisymmetric finite element model of the heatshield. We used the finite element model to predict the thermal stresses in the PICA from differential thermal expansion. The predicted peak compressive stress in the PICA heatshield was 1.38 MPa. Although this level of stress exceeded the chosen design limit for compressive stresses in PICA tiles for the design of the Orion crew exploration vehicle heatshield, the Stardust heatshield exhibited no obvious mechanical failures from thermal stress. The analyses of the Stardust heatshield were used to assess and adjust the level of conservatism in the finite element analyses in support of the Orion heatshield design.

  14. Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions

    Directory of Open Access Journals (Sweden)

    Yusuke Takahashi

    2016-01-01

    Full Text Available A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD of the European Space Agency (ESA in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense plasma derived from a strong shock wave generated in front of the capsule because of orbital speed during reentry. In this study, the physical properties of the plasma flow in the shock layer and wake region of the ESA ARD were obtained using a computational fluid dynamics technique. Then, electromagnetic waves were expressed using a frequency-dependent finite-difference time-domain method using the plasma properties. The analysis model was validated based on experimental flight data. A comparison of the measured and predicted results showed good agreement. The distribution of charged particles around the ESA ARD and the complicated behavior of electromagnetic waves, with attenuation and reflection, are clarified in detail. It is suggested that the analysis model could be an effective tool for investigating radio frequency blackout and plasma attenuation in radio wave communication.

  15. Reentry produced by small-scale heterogeneities in a discrete model of cardiac tissue

    Science.gov (United States)

    Alonso, Sergio; Bär, Markus

    2016-06-01

    Reentries are reexcitations of cardiac tissue after the passing of an excitation wave which can cause dangerous arrhythmias like tachycardia or life-threatening heart failures like fibrillation. The heart is formed by a network of cells connected by gap junctions. Under ischemic conditions some of the cells lose their connections, because gap junctions are blocked and the excitability is decreased. We model a circular region of the tissue where a fraction of connections among individual cells are removed and substituted by non-conducting material in a two-dimensional (2D) discrete model of a heterogeneous excitable medium with local kinetics based on electrophysiology. Thus, two neighbouring cells are connected (disconnected) with a probability ϕ (1 - ϕ). Such a region is assumed to be surrounded by homogeneous tissue. The circular heterogeneous area is shown to act as a source of new waves which reenter into the tissue and reexcitate the whole domain. We employ the Fenton-Karma equations to model the action potential for the local kinetics of the discrete nodes to study the statistics of the reentries in two dimensional networks with different topologies. We conclude that the probability of reentry is determined by the proximity of the fraction of disrupted connections between neighboring nodes (“cells”) in the heterogeneous region to the percolation threshold.

  16. Reusable Reentry Satellite (RRS) system design study: System cost estimates document

    Science.gov (United States)

    1991-01-01

    The Reusable Reentry Satellite (RRS) program was initiated to provide life science investigators relatively inexpensive, frequent access to space for extended periods of time with eventual satellite recovery on earth. The RRS will provide an on-orbit laboratory for research on biological and material processes, be launched from a number of expendable launch vehicles, and operate in Low-Altitude Earth Orbit (LEO) as a free-flying unmanned laboratory. SAIC's design will provide independent atmospheric reentry and soft landing in the continental U.S., orbit for a maximum of 60 days, and will sustain three flights per year for 10 years. The Reusable Reentry Vehicle (RRV) will be 3-axis stabilized with artificial gravity up to 1.5g's, be rugged and easily maintainable, and have a modular design to accommodate a satellite bus and separate modular payloads (e.g., rodent module, general biological module, ESA microgravity botany facility, general botany module). The purpose of this System Cost Estimate Document is to provide a Life Cycle Cost Estimate (LCCE) for a NASA RRS Program using SAIC's RRS design. The estimate includes development, procurement, and 10 years of operations and support (O&S) costs for NASA's RRS program. The estimate does not include costs for other agencies which may track or interface with the RRS program (e.g., Air Force tracking agencies or individual RRS experimenters involved with special payload modules (PM's)). The life cycle cost estimate extends over the 10 year operation and support period FY99-2008.

  17. Study on Mini Re-Entry System Using Deployable Membrane Aeroshell

    Science.gov (United States)

    Koyama, Masashi; Suzuki, Kojiro; Imamura, Osamu; Yamada, Kazuhiko

    An aeroshell made from membrane material have an advantage of reduction in the aerodynamic heating, because its small mass and large area enable us to make the low-ballistic-coefficient flight, in which the vehicle decelerates at very high altitude with low atmospheric density. In this paper, we propose a new concept of mini re-entry system for small satellites. This vehicle is called "FEATHER" (Flexible Expanded Aeroshell with Tiny payload Harness for Entry and Recovery). "FEATHER" is a novel re-entry and recovery system, featuring the autonomous aeroshell deployment, the low-ballistic-coefficient re-entry with less severe aerodynamicc heating and so on. FEATHER is composed of the membrane aeroshell made from the high-temperature cloth called ZYLON®, an outer frame made of Shape Memory Alloy (SMA) and a payload. When the aeroshell receives the aerodynamic heating, the temperature of SMA frame rises and restores the circular shape as memorized beforehand. Then the membrane aeroshell is automatically deployed. Therefore the vehicle can achieve the low-ballistic-coefficient flight with a drastic reduction in the aerodynamic heating without any additional sensors, controllers and actuators. The preliminary studies made on FEATHER system so far including the hypersonic wind tunnel experiments are presented in this paper.

  18. Re-Entries: New strategies in development zones at the Orinoco Oil Belt

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, R.; Briceno, M.; Figueroa, J.; Bolanos, C. [Lagoven, S.A., Morichal, Edo. Monagas (Venezuela)

    1996-08-01

    Drilling of horizontal wells in Venezuela began in the Orinoco Oil Belt with the wells CI-87 and CI-97 in the J-20 block, drilled in 1989 and 1990, respectively. Well CI-87 produces up to 1000 BPD without steam injection. Due to the success of this well, the exploitation strategy was oriented toward re-entry and sidetracking wells with mechanical problems, high water cut and low potential. The purpose of this programme was to enhance drainage patterns, access new reservoirs through existing bores, and increase oil production while reducing per-barrel costs. Eighteen (18) wells were re-drilled in different pay zones such as O-12, O-13, O-14 and O-15 with horizontal sections between a thousand feet and one thousand six hundred feet. Those wells were completed with progressive cavity pumps, sucker rod beam pumps and electrical submersible pumps. Presented in this paper are the results of the re-entries at the Orinoco Oil Belt and the future re-entry strategy.

  19. Drivers’ Visual Search Patterns during Overtaking Maneuvers on Freeway

    Directory of Open Access Journals (Sweden)

    Wenhui Zhang

    2016-11-01

    Full Text Available Drivers gather traffic information primarily by means of their vision. Especially during complicated maneuvers, such as overtaking, they need to perceive a variety of characteristics including the lateral and longitudinal distances with other vehicles, the speed of others vehicles, lane occupancy, and so on, to avoid crashes. The primary object of this study is to examine the appropriate visual search patterns during overtaking maneuvers on freeways. We designed a series of driving simulating experiments in which the type and speed of the leading vehicle were considered as two influential factors. One hundred and forty participants took part in the study. The participants overtook the leading vehicles just like they would usually do so, and their eye movements were collected by use of the Eye Tracker. The results show that participants’ gaze durations and saccade durations followed normal distribution patterns and that saccade angles followed a log-normal distribution pattern. It was observed that the type of leading vehicle significantly impacted the drivers’ gaze duration and gaze frequency. As the speed of a leading vehicle increased, subjects’ saccade durations became longer and saccade angles became larger. In addition, the initial and destination lanes were found to be key areas with the highest visual allocating proportion, accounting for more than 65% of total visual allocation. Subjects tended to more frequently shift their viewpoints between the initial lane and destination lane in order to search for crucial traffic information. However, they seldom directly shifted their viewpoints between the two wing mirrors.

  20. Aeroelastic optimization design for wing with maneuver load uncertainties

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An aeroelastic optimization design methodology for air vehicle considering the uncertainties in maneuver load conditions is presented and applied to a structural design process of low-aspect-ratio wing. An aerodynamic load correction model is developed and used to predict the critical load conditions with the perturbations of theoretical linear aerodynamic forces and experimental aerodynamic forces from wind-tunnel test, when concerning the uncertainties in use of theoretical linear and experimental aerodynamic forces. Three objective functions of critical loads are defined. The load evaluations for three wing sections are investigated in four characteristic maneuvers, and the most critical load conditions are confirmed by using the sequential quadratic programming method. On this basis, the aeroelastic optimization design employing the genetic-gradient hybrid algorithm is conducted, in which the objective is to minimize structural mass subject to the constraints of stress, deformation and flutter speed. The resulting optimal structure is heavier than the one simply based on the theoretical linear or experimental aerodynamic forces. However, it is more robust when encountering the critical load conditions in actual flight due to the consideration of uncertainties in aerodynamic forces in the early design phase, thereby, the risk of structural redesign can be reduced.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  3. Muscular Control of Turning and Maneuvering in Jellyfish Bells

    Science.gov (United States)

    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).

  4. Investigation of plasma–surface interaction effects on pulsed electrostatic manipulation for reentry blackout alleviation

    Science.gov (United States)

    Krishnamoorthy, S.; Close, S.

    2017-03-01

    The reentry blackout phenomenon affects most spacecraft entering a dense planetary atmosphere from space, due to the presence of a plasma layer that surrounds the spacecraft. This plasma layer is created by ionization of ambient air due to shock and frictional heating, and in some cases is further enhanced due to contamination by ablation products. This layer causes a strong attenuation of incoming and outgoing electromagnetic waves including those used for command and control, communication and telemetry over a period referred to as the ‘blackout period’. The blackout period may last up to several minutes and is a major contributor to the landing error ellipse at best, and a serious safety hazard in the worst case, especially in the context of human spaceflight. In this work, we present a possible method for alleviation of reentry blackout using electronegative DC pulses applied from insulated electrodes on the reentry vehicle’s surface. We study the reentry plasma’s interaction with a DC pulse using a particle-in-cell (PIC) model. Detailed models of plasma–insulator interaction are included in our simulations. The absorption and scattering of ions and electrons at the plasma–dielectric interface are taken into account. Secondary emission from the insulating surface is also considered, and its implications on various design issues is studied. Furthermore, we explore the effect of changing the applied voltage and the impact of surface physics on the creation and stabilization of communication windows. The primary aim of this analysis is to examine the possibility of restoring L- and S-band communication from the spacecraft to a ground station. Our results provide insight into the effect of key design variables on the response of the plasma to the applied voltage pulse. Simulations show the creation of pockets where electron density in the plasma layer is reduced three orders of magnitude or more in the vicinity of the electrodes. These pockets extend to

  5. EntrySat: A 3U CubeStat to study the reentry atmospheric environment

    Science.gov (United States)

    Anthony, Sournac; Raphael, Garcia; David, Mimoun; Jeremie, Chaix

    2016-04-01

    ISAE France Entrysat has for main scientific objective the study of uncontrolled atmospheric re-entry. This project, is developed by ISAE in collaboration with ONERA and University of Toulouse, is funded by CNES, in the overall frame of the QB50 project. This nano-satellite is a 3U Cubesat measuring 34*10*10 cm3, similar to secondary debris produced during the break up of a spacecraft. EntrySat will collect the external and internal temperatures, pressure, heat flux, attitude variations and drag force of the satellite between ≈150 and 90 km before its destruction in the atmosphere, and transmit them during the re-entry using the IRIDIUM satellite network. The result will be compared with the computations of MUSIC/FAST, a new 6-degree of freedom code developed by ONERA to predict the trajectory of space debris. In order to fulfil the scientific objectives, the satellite will acquire 18 re-entry sensors signals, convert them and compress them, thanks to an electronic board developed by ISAE students in cooperation with EREMS. In order to transmit these data every second during the re-entry phase, the satellite will use an IRIDIUM connection. In order to keep a stable enough attitudes during this phase, a simple attitude orbit and control system using magnetotorquers and an inertial measurement unit (IMU) is developed at ISAE by students. A commercial GPS board is also integrated in the satellite into Entry Sat to determine its position and velocity which are necessary during the re-entry phase. This GPS will also be used to synchronize the on-board clock with the real-time UTC data. During the orbital phase (≈2 year) EntrySat measurements will be recorded transmitted through a more classical "UHF/VHF" connection. Preference for presentation: Poster Most suitable session: Author for correspondence: Dr Raphael F. Garcia ISAE 10, ave E. Belin, 31400 Toulouse, France Raphael.GARCIA@isae.fr +33 5 61 33 81 14

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

    Science.gov (United States)

    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.

  7. When do drivers abort an overtaking maneuver 5 on two-lane rural roads

    NARCIS (Netherlands)

    Farah, H.

    2016-01-01

    Overtaking on two-lane roads is a complex driving maneuver. Drivers who desire to overtake a lead vehicle need to evaluate the available gaps in the opposite direction and accept a sufficient gap to successfully complete the overtaking maneuver. However, often drivers realize that the gap they acce

  8. Cases requiring increased number of repositioning maneuvers in benign paroxysmal positional vertigo

    Directory of Open Access Journals (Sweden)

    Mukadder Korkmaz

    Full Text Available ABSTRACT INTRODUCTION: Benign paroxysmal positional vertigo (BPPV is a clinical syndrome that is proposed to be caused by dislocated utricular debris into semicircular canals. Although the majority of patients are treated by one or two repositioning maneuvers, some of the patients need repeated maneuvers for relief. OBJECTIVE: The goal of this study was to investigate the factors associated with patients with benign paroxysmal positional vertigo who required multiple repositioning procedures for treatment. METHODS: Data were obtained from the clinical records of 153 patients diagnosed with benign paroxysmal positional vertigo. Patients were treated by repositioning maneuvers. Demographic data and the factors including age, sex, canal type, duration of symptoms, comorbidities and number of repositioning maneuvers for relief were documented for statistical analysis. RESULTS: Age, sex, canal type and the duration of symptoms had no impact on the number of maneuvers. The most common comorbidity was spine problems. Hypertension was the only comorbidity that significantly associated with increased number of maneuvers. CONCLUSION: The presence of hypertension is a risk factor for repeated maneuvers in benign paroxysmal positional vertigo treatment. Physicians should be aware of the increased probability of repeated repositioning maneuvers in these group of patients. The role of comorbidities and vascular factors need to be further clarified in the course of benign paroxysmal positional vertigo.

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

    Science.gov (United States)

    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,…

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

    Science.gov (United States)

    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.

  11. An activation-repolarization time metric to predict localized regions of high susceptibility to re-entry

    Science.gov (United States)

    Child, Nicholas; Bishop, Martin J.; Hanson, Ben; Coronel, Ruben; Opthof, Tobias; Bourkens, Bastiaan; Walton, Richard; Efimov, Igor; Bostock, Julian; Hill, Yolanda; Rinaldi, Christopher A; Razavi, Reza; Gill, Jaswinder; Taggart, Peter

    2015-01-01

    Background Initiation of re-entrant ventricular tachycardia (VT) involves complex interactions between activation and repolarization wavefronts. Recent experimental work has identified the time interval between S2 repolarization proximal to a line of functional block and the activation at the adjacent distal side, as a critical determinant of re-entry. Objective We hypothesized: (1) an algorithm could be developed which would generate a spatial map of this interval (designated the “re-entry vulnerability index”-RVI); (2) that this would accurately identify a pathway of re-entry as well as rotor formation in animal experiments and in a computational model; and, (3) that it would be possible to generate an RVI map in humans during routine clinical procedures and co-register with anatomical and electrophysiological features. Methods and Results An algorithm was developed which sampled all points on a multielectrode grid and calculated RVI between all pairs of electrodes within a given radius. The algorithm successfully identified the spatial region with increased susceptibility to re-entry in an established Langendorff pig heart model and the site of re-entry and rotor formation in an optically mapped sheep heart model and corresponding computational simulations. The feasibility of RVI mapping was evaluated during a clinical procedure by co-registering with the anatomy and physiology in a patient undergoing a VT ablation. Conclusions We developed an algorithm to calculate a re-entry vulnerability index from intervals between local repolarization and activation times at all adjacent points over a multielectrode grid. The algorithm accurately identified the region of re-entry in two animal models of functional re-entry. The possibility of clinical application was demonstrated in a patient with VT. PMID:25863160

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

    Science.gov (United States)

    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.

  13. The effect of maneuvers for shoulder delivery on perineal trauma

    DEFF Research Database (Denmark)

    Aabakke, Anna J M; Willer, Hanne; Krebs, Lone

    2016-01-01

    INTRODUCTION: Approximately 85% of vaginal deliveries are accompanied by perineal trauma. The objective of this trial was to compare the incidence of perineal trauma after primary delivery of either the anterior or posterior shoulder during vaginal delivery. MATERIAL AND METHODS: This was a rando......INTRODUCTION: Approximately 85% of vaginal deliveries are accompanied by perineal trauma. The objective of this trial was to compare the incidence of perineal trauma after primary delivery of either the anterior or posterior shoulder during vaginal delivery. MATERIAL AND METHODS......: This was a randomized single-blinded trial comparing primary delivery of either the anterior or posterior shoulder in women having their first vaginal delivery. Primary outcome was any perineal trauma. Results were analyzed according to the intention-to-treat principle and supplemented with a per-protocol and as...... or posterior shoulder. Consequently both maneuvers for shoulder delivery can be used at vaginal delivery, but further trials are warranted before certain methods can be recommended....

  14. Non-Toxic Orbital Maneuvering System Engine Development

    Science.gov (United States)

    Green, Christopher; Claflin, Scott; Maeding, Chris; Butas, John

    1999-01-01

    Recent results using the Aestus engine operated with LOx/ethanol propellant are presented. An experimental program at Rocketdyne Propulsion and Power is underway to adapt this engine for the Boeing Reusable Space Systems Division non-toxic Orbital Maneuvering System/Reaction control System (OMS/RCS) system. Daimler-Chrysler Aerospace designed the Aestus as an nitrogen tetroxide/monomethyl hydrazine (NTO/MMH) upper-stage engine for the Ariane 5. The non-toxic OMS/RCS system's preliminary design requires a LOx/ethanol (O2/C2H5OH) engine that operates with a mixture ratio of 1.8, a specific impulse of 323 seconds, and fits within the original OMS design envelope. This paper describes current efforts to meet these requirements including, investigating engine performance using LOx/ethanol, developing the en-ine system sizing package, and meeting the vehicle operation parameters. Data from hot-fire testing are also presented and discussed.

  15. Orbit Maneuver of Spinning Tether via Tidal Force

    CERN Document Server

    Baoyin, Hexi; Li, Junfeng

    2014-01-01

    Recently, the spinning tethered system is regarded as a typical and fundamental space structure attracting great interest of the aerospace engineers, and has been discussed primarily for specific space missions in past decades, including on-orbit capture and propellantless orbit transfer etc. The present work studies the dynamical behaviours of a fast spinning tethered binary system under central gravitational field, and derives principles of the basic laws of orbital maneuver. Considering the characteristics of coupled librational and orbital motions, an averaging method is introduced to deal with the slow-fast system equation, thus a definite equivalent model is derived. The general orbit motion is completely determined analytically, including the orbit geometry, periodicity, conversations and moving region etc. Since the possibility of orbit control using tether reaction has been proved by previous studies, special attention is paid to the transportation mode of angular momentum and mechanical energy betwe...

  16. Slew maneuver dynamics of the Spacecraft Control Laboratory experiment

    Science.gov (United States)

    Kakad, Y. P.

    1987-01-01

    Mathematical expressions for slew maneuver dynamics are presented. The total kinetic energy expression of the system is given as T = T(0) + T(1) + T(2), where T(0), T(1), and T(2) refer to the kinetic energies of the shuttle, the flexible beam, and the tip mass (the reflector), respectively. The specific equations for each of these are defined and integrated into the total energy expression. Using the chain rule in the Lagrange equations and an expression allowing the transformation of the orbiter angular velocity from the inertial frame to the body-fixed frame, the rotational equations are obtained. Finally, the vibration equations for the beam are derived, again using the Lagrange equations.

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

    Science.gov (United States)

    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.

  18. Potential application of X-ray communication through a plasma sheath encountered during spacecraft reentry into earth's atmosphere

    Science.gov (United States)

    Li, Huan; Tang, Xiaobin; Hang, Shuang; Liu, Yunpeng; Chen, Da

    2017-03-01

    Rapid progress in exploiting X-ray science has fueled its potential application in communication networks as a carrier wave for transmitting information through a plasma sheath during spacecraft reentry into earth's atmosphere. In this study, we addressed the physical transmission process of X-rays in the reentry plasma sheath and near-earth space theoretically. The interactions between the X-rays and reentry plasma sheath were investigated through the theoretical Wentzel-Kramers-Brillouin method, and the Monte Carlo simulation was employed to explore the transmission properties of X-rays in the near-earth space. The simulation results indicated that X-ray transmission was not influenced by the reentry plasma sheath compared with regular RF signals, and adopting various X-ray energies according to different spacecraft reentry altitudes is imperative when using X-ray uplink communication especially in the near-earth space. Additionally, the performance of the X-ray communication system was evaluated by applying the additive white Gaussian noise, Rayleigh fading channel, and plasma sheath channel. The Doppler shift, as a result of spacecraft velocity changes, was also calculated through the Matlab Simulink simulation, and various plasma sheath environments have no significant influence on X-ray communication owing to its exceedingly high carrier frequency.

  19. Beta-carotene

    Science.gov (United States)

    ... patches on the tongue and mouth called oral leukoplakia. Taking beta-carotene by mouth for up to 12 months seems to decrease symptoms of oral leukoplakia. Osteoarthritis. Beta-carotene taken by mouth may prevent ...

  20. 'What on earth can this possibly mean'? French reentry courts and experts' risk assessment.

    Science.gov (United States)

    Herzog-Evans, Martine

    2016-01-01

    Against the backdrop of ten years of punitive criminal justice policies, the number of cases in which risk assessments by psychiatrist experts are mandatory has considerably increased in France. Because of complex and deeply ingrained cultural factors, most experts and academics oppose the use of actuarial or other structured judgement tools, which they assimilate to these policy changes. Parallel to this, the reentry judges in charge of making release and other community sentence decisions have maintained a strong rehabilitative and desistance-focused culture. Drawing on interviews with these judges and experts, the author wanted to assess the judges' expectations of experts' reports, their opinion on actuarial tools, and how they perceived experts and their aptitude to assess risk. The study showed that French reentry judges manage to keep experts' conclusions at bay when they do not fit with their desistance goals, as they can draw upon their own expertise and that of probation services. They do not have much faith in the professionalism and methodology of experts, and would like them to better demonstrate how they reach their conclusions. Moreover, criminogenic needs assessment would be much more useful to them than static risk assessment, which raises the issue as to why this is not the French probation services' role. Reentry judges who never encountered a report which uses a structured tool are influenced by the French ideological debate; those who have read such reports are unanimously in favour of such tools. It thus seems clear that they would like experts to be more strongly guided by science, but are not yet fully aware of what this entails.

  1. Precise orbit determination of a maneuvered GEO satellite using CAPS ranging data

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Wheel-off-loadings and orbital maneuvers of the GEO satellite result in additional accelerations to the satellite itself. Complex and difficult to model, these time varying accelerations are an important error source of precise orbit determination (POD). In most POD practices, only non-maneuver orbital arcs are treated. However, for some applications such as satellite navigation RDSS services, uninterrupted orbital ephemeris is demanded, requiring the development of POD strategies to be processed both during and after an orbital maneuver. We in this paper study the POD for a maneuvered GEO satellite, using high precision and high sampling rate ranging data obtained with Chinese Area Positioning System (CAPS). The strategy of long arc POD including maneuver arcs is studied by using telemetry data to model the maneuver thrust process. Combining the thrust and other orbital perturbations, a long arc of 6 days’ CAPS ranging data is analyzed. If the telemetry data are not available or contain significant errors, attempts are made to estimate thrusting parameters using CAPS ranging data in the POD as an alternative to properly account for the maneuver. Two strategies achieve reasonably good data fitting level in the tested arc with the maximal position difference being about 20 m.

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

    Science.gov (United States)

    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. Momentum balance, hydrodynamic impulse and choreography in rapidly maneuvering live fish

    Science.gov (United States)

    Epps, B. P.; Techet, A. H.

    2006-11-01

    It is well known that swimming fish can swim circles around underwater vehicles when it comes to maneuvering performance. A typical underwater vehicle sweeps a circular arc, about ten vehicle lengths in diameter, and this requires about 15 times the amount of time it takes for the vehicle to drive one body length. In contrast, a fish, such as the Danio aequipinnatus, can turn in a space that is approximately one third of its body length, and it requires about half the time it takes to swim one body length. High-speed Particle Imaging Velocimetry (PIV) is used to quantify the impulse imparted to the fluid during a maneuver which is compared to the change in momentum of the fish during the maneuver. In order to model the impulse of the fluid, we make the assumption that the wake may be modeled as an axisymmetric vortex ring. The evidence that this is an appropriate model comes from a recent study of rapidly maneuvering flapping foils. Our PIV results show that the fish in fact generates two such wakes, one generated by the tail and shed at the conclusion of stage one of the maneuver and the other generated by the mid-section of the body and shed at the conclusion of stage two of the maneuver. Both of these vertical impulses are required to balance the momentum change of the fish from its initial swimming trajectory to its final swimming trajectory in a classical C-shaped maneuver.

  4. Precise orbit determination of a maneuvered GEO satellite using CAPS ransing data

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong; HU XiaoGong; HUANG Cheng; YANG QiangWen; JIAO WenHai

    2009-01-01

    Wheel-off-loadings and orbital maneuvers of the GEO satellite result in additional accelerations to the satellite itself.Complex and difficult to model,these time varying accelerations are an important error source of precise orbit determination (POD).In most POD practices,only non-maneuver orbital arcs are treated.However,for some applications such as satellite navigation RDSS services,uninterrupted orbital ephemeris is demanded,requiring the development of POD strategies to be processed both during and after an orbital maneuver.We in this paper study the POD for a maneuvered GEO satellite,using high precision and high sampling rate ranging data obtained with Chinese Area Positioning System (CAPS).The strategy of long arc POD including maneuver arcs is studied by using telemetry data to model the maneuver thrust process.Combining the thrust and other orbital perturbations,a long arc of 6 days' CAPS ranging data is analyzed.If the telemetry data are not available or contain significant errors,attempts are made to estimate thrusting parameters using CAPS ranging data in the POD as an alternative to properly account for the maneuver.Two strategies achieve reasonably good data fitting level in the tested arc with the maximal position difference being about 20m.

  5. Precise orbit determination of a maneuvered GEO satellite using CAPS ranging data

    Science.gov (United States)

    Huang, Yong; Hu, Xiaogong; Huang, Cheng; Yang, Qiangwen; Jiao, Wenhai

    2009-03-01

    Wheel-off-loadings and orbital maneuvers of the GEO satellite result in additional accelerations to the satellite itself. Complex and difficult to model, these time varying accelerations are an important error source of precise orbit determination (POD). In most POD practices, only non-maneuver orbital arcs are treated. However, for some applications such as satellite navigation RDSS services, uninterrupted orbital ephemeris is demanded, requiring the development of POD strategies to be processed both during and after an orbital maneuver. We in this paper study the POD for a maneuvered GEO satellite, using high precision and high sampling rate ranging data obtained with Chinese Area Positioning System (CAPS). The strategy of long arc POD including maneuver arcs is studied by using telemetry data to model the maneuver thrust process. Combining the thrust and other orbital perturbations, a long arc of 6 days’ CAPS ranging data is analyzed. If the telemetry data are not available or contain significant errors, attempts are made to estimate thrusting parameters using CAPS ranging data in the POD as an alternative to properly account for the maneuver. Two strategies achieve reasonably good data fitting level in the tested arc with the maximal position difference being about 20 m.

  6. Application of Extended Kalman Filter to Tactical Ballistic Missile Re-entry Problem

    CERN Document Server

    Bhowmik, Subrata

    2007-01-01

    The objective is to investigate the advantages and performance of Extended Kalman Filter for the estimation of non-linear system where linearization takes place about a trajectory that was continually updated with the state estimates resulting from the measurement. Here tactile ballistic missile Re-entry problem is taken as a nonlinear system model and Extended Kalman Filter technique is used to estimate the positions and velocities at the X and Y direction at different values of ballistic coefficients. The result shows that the method gives better estimation with the increase of ballistic coefficient.

  7. Review of ESOC re-entry prediction results of Salyut-7/Kosmos-1686

    Science.gov (United States)

    Klinkrad, H.

    1991-01-01

    An overview of activities at ESA/ESOC during the followup of the Salyut-7/Kosmos-1686 decay, and of related cooperations with space agencies, research institutes, and national bodies within the ESA Member States, within the U.S. and within the USSR, is presented. A postflight analysis indicated areas for improvement in the forecast procedures, especially during the last day of the orbital lifetime. Corresponding revised decay predictions are presented for Salyut-7/Kosmos-1686, and the improved procedures are verified by an analysis of the reentries of Kosmos-1402A and Kosmos-1402C.

  8. OVERFLOW Simulations of Space Shuttle Orbiter Reentry Based on As-Built Geometry

    Science.gov (United States)

    Ma, Edward C.; Vicker, Darby J.; Campbell, Charles H.; Wilson, Brad; Pavek, Mike; Berger, Karen

    2012-01-01

    The Space Shuttle Orbiters Discovery and Endeavor have been digitally scanned to obtain outer mold line surfaces. Using these scans, the existing overset computational fluid dynamics (CFD) grid system will be modified by projecting the grid points to the scanned geometry. Simulations will be performed using the OVERFLOW solver and the results compared to previous OVERFLOW results on the theoretical geometry and the aerodynamic databook. The "bent airframe" term will be compared between the aerodynamic databook and the computations over a range of reentry conditions.

  9. [Treatment of the benign paroxysmal positional vertigo (BPPV) by Epley maneuver].

    Science.gov (United States)

    Pino Rivero, V; Pantoja Hernández, C G; González Palomino, A; Mora Santos, M E; Marcos García, M; Montero García, C; Blasco Huelva, A

    2007-01-01

    Benign paroxysmal positional vertigo (BPPV) is the most common of the peripheral vertigo. We report the case of a 45 years old female with that pathology suspected by the symptoms which the patient related to head changes of positions and movements. Her diagnosis was confirmed by the maneuver of Dix-Hallpike, that was positive, and the treatment consisted in a maneuver of canalicular reposition according to Epley's technique. Such maneuver was successful and actually the patient is without symptoms after more than 2 years since the first episode. Finally we have performed a bibliographic review to verify the effectiveness of that treatment.

  10. Traumatic dissection and rupture of the abdominal aorta as a complication of the Heimlich maneuver.

    Science.gov (United States)

    Desai, Shaun C; Chute, Dennis J; Desai, Bharati C; Koloski, Eugene R

    2008-11-01

    Although the Heimlich maneuver is considered the best intervention for relieving acute upper airway obstruction, several complications have been reported in the literature. These complications can occur as a result of an increase in abdominal pressure leading to a variety of well-documented visceral injuries, including the great vessels. Acute abdominal aortic thrombosis after the Heimlich maneuver is a rare but recognized event; however, to date no case of traumatic dissection and rupture of the abdominal aorta has been described. We report the first known case, to our knowledge, of a traumatic dissection and rupture of the abdominal aorta after a forcefully applied Heimlich maneuver.

  11. Proximal aortic stent-graft displacement with type I endoleak due to Heimlich maneuver.

    Science.gov (United States)

    Lin, Peter H; Bush, Ruth L; Lumsden, Alan B

    2003-08-01

    The Heimlich maneuver has saved countless lives by relieving foreign body obstruction from the respiratory tract. Complications related to this life-saving technique, particularly involving the abdominal aorta, are extremely rare. We report the case of a patient who underwent successful endovascular abdominal aortic aneurysm (AAA) repair, with AAA reduction at postoperative surveillance. Endograft displacement after performance of the Heimlich maneuver resulted in a proximal type I endoleak. This case underscores both the potential for aortic trauma from the Heimlich maneuver and the risk for clinical failure as a result of abdominal compression after successful endovascular AAA repair.

  12. Associating crash avoidance maneuvers with driver attributes and accident characteristics: a mixed logit model approach

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2012-01-01

    from the key role of proactive and state-aware road users within the concept of sustainable safety systems, as well as from the key role of effective corrective maneuvers in the success of automated in-vehicle warning and driver assistance systems. Methods: The analysis is conducted by means of a mixed...... the propensity to perform crash avoidance maneuvers, and (5) visual obstruction and artificial illumination decrease the probability to carry out crash avoidance maneuvers. Conclusions: The results emphasize the need for public awareness campaigns to promote safe driving style for senior drivers and warning...

  13. Development and flight test of an experimental maneuver autopilot for a highly maneuverable aircraft

    Science.gov (United States)

    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.

  14. Development of a flight test maneuver autopilot for a highly maneuverable aircraft

    Science.gov (United States)

    Duke, E. L.; Jones, F. P.; Roncoli, R. B.

    1983-01-01

    This paper details the development of a flight test maneuver autopilot for a highly maneuverable aircraft. This newly developed flight test technique is being applied at the Dryden Flight Research Facility of the NASA Ames Research Center. The flight test maneuver autopilot (FTMAP) is designed to increase the quantity and quality of the data obtained in flight test. The vehicle with which it is being used is the highly maneuverable aircraft technology (HiMAT) vehicle. This paper describes the HiMAT vehicle systems, maneuver requirements, FTMAP development process, and flight results.

  15. Forward-Looking Betas

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Jacobs, Kris; Vainberg, Gregory

    Few issues are more important for finance practice than the computation of market betas. Existing approaches compute market betas using historical data. While these approaches differ in terms of statistical sophistication and the modeling of the time-variation in the betas, they are all backward......-looking. This paper introduces a radically different approach to estimating market betas. Using the tools in Bakshi and Madan (2000) and Bakshi, Kapadia and Madan (2003) we employ the information embedded in the prices of individual stock options and index options to compute our forward-looking market beta...

  16. Long-term clinical observation of treatment of infrabony defects with enamel matrix derivative (Emdogain): surgical reentry.

    Science.gov (United States)

    Rasperini, Giulio; Silvestri, Maurizio; Ricci, Giano

    2005-04-01

    A surgical protocol for the placement of Emdogain during new attachment procedures was published in this journal in 1999. Three cases with infrabony defects were treated, and significant periodontal attachment level gain, probing depth reduction, and bone fill were evident upon clinical probing and reentry procedures after 1 year. The patients were enrolled in a maintenance protocol with 3-month recall visits. After 7 years, the clinical parameters were stable, as was the radiographic evaluation. Surgical reentry after 7 years in two cases and 5 years in one case demonstrated the stability of the previous findings. These data show the long-term efficacy of enamel matrix derivative in new attachment procedures.

  17. Application of numerical methods to extend capabilities for optimal rocket guidance: report on reentry guidance of shuttle orbiter

    Science.gov (United States)

    1972-01-01

    Analytical models are presented for optimal trajectories and reentry guidance of the space shuttle orbiter. Major emphasis is placed on the development of a "footprint', which refers to a set of reachable destination positions attainable by the shuttle at a specified terminal altitude. An unconstrained reentry footprint was calculated for a shuttle vehicle which enters the earth's atmosphere at 93 km initial altitude after a deboost from a near earth orbit. The method of computation is briefly described, and graphs are presented which illustrate the footprint and the variation of state and control variables along it. The effects of constraints and of variations in initial state upon the footprint are discussed.

  18. Cardiac tamponade arising from a venous source following anterograde dissection re-entry coronary angioplasty to a chronic total occlusion.

    Science.gov (United States)

    Danson, E; Arena, F; Sapontis, J; Ward, M; Bhindi, R

    2016-10-01

    Cardiac tamponade is a rare complication of coronary intervention to chronic total occlusions (CTO PCI). We report a case of persistent bleeding from a venous source following successful anterograde dissection-reentry (ADR) CTO PCI. Pericardiocentesis was performed 1 h post-procedure for tamponade. Persistent bleeding was investigated with contrast transesophageal echocardiography, pericardial manometry and blood analysis. Coronary venography revealed subtle extravasation from a cardiac vein adjacent to the site of luminal re-entry. Coronary venous perforation using ADR CTO PCI has not previously been described; however, the volume of blood loss may be significant and surgical exploration may be appropriate.

  19. Mission analysis and guidance, navigation, and control design for rendezvous and docking phase of advanced reentry vehicle mission

    Science.gov (United States)

    Strippoli, L.; Colmenarejo, P.; Strauch, H.

    2013-12-01

    Advanced Reentry Vehicle (ARV) belongs to the family of vehicles designed to perform rendezvous and docking (RvD) with the International space station (ISS) [1]. Differently from its predecessor ATV (Automated Transfer Vehicle), the ARV will transport a reentry capsule, equipped with a heatshield and able to bring back cargo, experiments, or, as a possible future development, even crew, being this latter scenario very attracting in view of the Space Shuttle retirement. GMV, as subcontractor of EADS-Astrium Germany, is in charge of the RvD and departure mission analysis and GNC (Guidance, Navigation, and Control) design of ARV mission. This paper will present the main outcomes of the study.

  20. The rotation modulation inertial navigation system for blackout area during hypersonic reentry

    Science.gov (United States)

    Li, Jin; Zhao, Jianhui; Sha, Xiaoqiang; Li, Fan

    2016-10-01

    Navigation of Hypersonic vehicles in the radio frequency (RF) blackout area during atmospheric reentry is challenging as the vehicles can only use the inertial navigation system (INS) as autonomous navigation method in this area. In this paper, strapdown inertial navigation system (SINS) based on the Fiber Optic Gyroscope (FOG) is used for navigation in blackout area. However, without external navigation measurement, the errors of SINS caused by the FOG drift and accelerometer bias would cumulate with time and degrade navigation accuracy. To solve this problem, single axis rotation modulation along with the azimuth axis of the body frame is adopted. The Generic Hypersonic Vehicle (GHV) model designed by NASA Langley Research Center is used to build the reentry fight model which can generate navigation information for simulation. Through derivation the error equations of FOG SINS in the North-East-Down (NED) navigation frame, the principle of error compensation by rotation modulation can be well understood. The simulation results show that rotation modulation can effectively decrease the impact of inertial sensor drift and improve the navigation accuracy in blackout area.

  1. Adaptive guidance law design based on characteristic model for reentry vehicles

    Institute of Scientific and Technical Information of China (English)

    YANG JunChun; HU Jun; NI MaoLin

    2008-01-01

    In this paper an adaptive guidance law based on the characteristic model is designed to track a reference drag acceleration for reentry vehicles like the Shuttle. The characteristic modeling method of linear constant systems is extended for single-input and single-output (SlSO) linear time-varying systems so that the characteristic model can be established for reentry vehicles. A new nonlinear differential golden-section adaptive control law is presented. When the coefficients belong to a bounded closed convex set and their rate of change meets some constraints, the uniformly asymptotic stability of the nonlinear differential golden-section adaptive control system is proved. The tracking control law, the nonlinear differential golden-section control law, and the revised logical integral control law are integrated to design an adaptive guidance law based on the characteristic model. This guidance law overcomes the disadvantage of the feedback linearization method which needs the precise model. Simulation results show that the proposed method has better performance of tracking the reference drag acceleration than the feedback linearization one.

  2. Design of Optimal Attack-Angle for RLV Reentry Based on Quantum Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    Qingzhen Zhang

    2014-04-01

    Full Text Available The attack-angle optimization is a key problem for reentry trajectory design of a gliding type reusable launch vehicle (RLV. In order to solve such a problem, the equations of motion are derived first. A physical programming (PP method is briefly presented and the preference function is reflected in mathematical representation. The attack-angle optimization problem with four criteria (i.e., downrange, total heat, heat rate, and trajectory oscillation is converted into a single-objective optimization problem based on the PP method. A winged gliding reentry RLV is chosen as a simulation example and the transformed single-objective problem is solved by the quantum-behaved particle swarm optimization (QPSO algorithm based on two types of preference structures, longer range preference and smaller total heat preference. The constraints of maximizing heating rate, normal load factor, and dynamic pressure and minimizing terminal velocity are handled by a penalty function method. The simulation results demonstrate the efficiency of these methods. The physical causation of the optimal solution and the typical profiles are presented, which reflect the designer's preference. At last, the feasibility and advantages of QPSO are revealed by comparison with the results of genetic algorithm (GA and standard particle swarm optimization (PSO algorithm on this optimization problem.

  3. Reactivation of wells through reentries with a horizontal section in unconsolidated heavy oil sands

    Energy Technology Data Exchange (ETDEWEB)

    Bolanos, C.; Suarez, S.; Silvera, M. [LAGOVEN, Maturin (Venezuela)

    1995-12-31

    The current exploitation areas of heavy oil are located in southern Monagas and have an estimated STOOIP of 26.5 MMMBLs. The production mechanisms are bottom water drive and rock expansion. Cumulative production reaches 685 million barrels up to July 1994. In order to optimize the exploitation of the heavy and extra heavy oil remaining reserves by lowering the pressure drop between reservoir and the wellbore, reduce costs to increase the profits from these reservoirs, a program of horizontal redrill or {open_quotes}reentries,{close_quotes} as known widely, was started. This paper presents the experiences and results obtained after 41 horizontal reentries made in Jobo, Pilon, and Morichal Fields in the period April 1993 to July 1994. Up to July 1994 wells were active with an associated of 21.7 MBOPD with an average of 20% water cut, confirming the successful application of this technology in heavy oils and unconsolidated sands. Several points will be discussed such as reservoir characteristics, well design, horizontal length, productivity index, drilling, completion, water production, surface equipment, and production of horizontal wells compared with vertical wells.

  4. Dynamic and Static High Temperature Resistant Ceramic Seals for X- 38 re-Entry Vehicle

    Science.gov (United States)

    Handrick, Karin E.; Curry, Donald M.

    2002-01-01

    In a highly successful partnership, NAS A, ESA, DLR (German Space Agency) and European industry are building the X-38, V201 re-entry spacecraft, the prototype of the International Space Station's Crew Return Vehicle (CRV). This vehicle would serve both as an ambulance for medical emergencies and as an evacuation vehicle for the Space Station. The development of essential systems and technologies for a reusable re-entry vehicle is a first for Europe, and sharing the development of an advanced re-entry spacecraft with foreign partners is a first for NASA. NASA, in addition to its subsystem responsibilities, is performing overall X-38 vehicle system engineering and integration, will launch V201 on the Space Shuttle, deliver flight data for post-flight analysis and assessment and is responsible for development and manufacture of structural vehicle components and thermal protection (TPS) tiles. The major European objective for cooperation with NASA on X-38 was to establish a clear path through which key technologies needed for future space transportation systems could be developed and validated at affordable cost and with controlled risk. Europe has taken the responsibility to design and manufacture hot control surfaces like metallic rudders and ceramic matrix composites (CMC) body flaps, thermal protection systems such as CMC leading edges, the CMC nose cap and -skirt, insulation, landing gears and elements of the V201 primary structure. Especially hot control surfaces require extremely high temperature resistant seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent overheating of these structures and possible loss of the vehicle. Complex seal interfaces, which have to fulfill various, tight mission- and vehicle-related requirements exist between the moveable ceramic body flaps and the bottom surface of the vehicle, between the rudder and fin structure and the ceramic leading edge panel and TPS tiles. While NASA

  5. Real-Time, Maneuvering Flight Noise Prediction for Rotorcraft Flight Simulations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal outlines a plan for developing new technology to provide accurate real-time noise prediction for rotorcraft in steady and maneuvering flight. Main...

  6. Efficacy of Epley’s Maneuver in Treating BPPV Patients: A Prospective Observational Study

    Directory of Open Access Journals (Sweden)

    Sushil Gaur

    2015-01-01

    Full Text Available 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.

  7. Efficacy of Epley's Maneuver in Treating BPPV Patients: A Prospective Observational Study

    Science.gov (United States)

    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

  8. Fatal splenic rupture following Heimlich maneuver: case report and literature review.

    Science.gov (United States)

    Cecchetto, Giovanni; Viel, Guido; Cecchetto, Attilio; Kusstatscher, Stefano; Montisci, Massimo

    2011-06-01

    The most effective resuscitative procedure in choking by foreign bodies is the Heimlich maneuver, described for the first time by Henry Heimlich (1974) and recognized by the US Surgeon General (1985) as the "only method that should be used for the treatment of choking from foreign body airway obstruction." If performed correctly, this lifesaving maneuver is associated with rare complications, of which the most frequent are rib fractures and gastric or esophagus perforations. Other rare traumatic injuries such as pneumomediastinum, aortic valve cusp rupture, diaphragmatic herniation, jejunum perforation, hepatic rupture, or mesenteric laceration have been described.However, we are unaware of previous reports of splenic rupture after Heimlich maneuver. We present an interesting case of fatal hemoperitoneum due to a hilar laceration of the spleen following a correctly performed Heimlich maneuver.

  9. A Computer Simulation of the System-Wide Effects of Parallel-Offset Route Maneuvers

    Science.gov (United States)

    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.

  10. Method to maintain artificial gravity during transfer maneuvers for tethered spacecraft

    Science.gov (United States)

    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.

  11. Comparison of various schema of filter adaptivity for the tracking of maneuvering targets

    Science.gov (United States)

    Jouan, Alexandre; Bosse, Eloi; Simard, Marc-Alain; Shahbazian, Elisa

    1998-09-01

    Tracking maneuvering targets is a complex problem which has generated a great deal of effort over the past several years. It has now been well established that in terms of tracking accuracy, the Interacting Multiple Model (IMM) algorithm, where state estimates are mixed, performs significantly better for maneuvering targets than other types of filters. However, the complexity of the IMM algorithm can prohibit its use in these applications of which similar algorithms cannot provide the necessary accuracy and which can ont afford the computational load of IMM algorithm. This paper presents the evaluation of the tracking accuracy of a multiple model track filter using three different constant-velocity models running in parallel and a maneuver detector. The output estimate is defined by selecting the model whose likelihood function is lower than a target maneuver threshold.

  12. Proportional Plus Integral Control of Aircraft for Automated Maneuvering Formation Flight

    Science.gov (United States)

    1991-12-01

    3-11 3.6 Formation Kinematic Equations Development 3-12 3.7 Aircraft Longitudinal (X) Channel Maneuvering 3-17 3.8 Aircraft Lateral (Y...response of the respective aircraft . Longitudinal position along the flight path vector is a direct function of forward velocity. Velocity is determined by...equation is not needed. 3-16 3.7 Aircraft Longitudinal (X) Channel Maneuvering The longitudinal channel involves the longitudinal separation distance

  13. Efficacy of Epley maneuver in treatment of benign paroxysmal positional vertigo of the posterior semicircular canal

    Directory of Open Access Journals (Sweden)

    Babac Snežana

    2012-01-01

    Full Text Available Background/Aim. Benign paroxysmal positional vertigo is one of the most frequent peripheral vestibular system disorders. The aim of this study was to examine the efficacy of the Epley maneuver in treating benign paroxysmal positional vertigo of the posterior semicircular canal (p- BPPV and to discover possible causes of failure. Methods. This prospective study included 75 patients. In all the cases medical history showed and the positioning Dix-Hallpike test confirmed the diagnosis of p-BPPV. We also performed clinical ENT examination, searching for spontaneous nystagmus, vestibulospinal tests, caloric test, and audiometry. All the patients were treated by the modified Epley canalith repositioning maneuver. The patients were followed up at the intervals of seven and, fourteen days, and one, tree, and six months and one year. The maneuver was repeated if vertigo and nystagmus on control positioning test persisted. The transition from positive into negative Dix Hallpike test after one or two Epley maneuver was considered as success in treatment. Results. After the initial Epley maneuver the recovery rate was 90.7%, and after the second 96%. In three (4% patients with secondary p-BPPV, symptoms did not cease even after the second repositioning maneuver. The etiology of p-BPPV had a significant effect on the maneuver’s success rate (p < 0.01, whereas duration of symptoms, age and gender had no effect (p > 0.05. After a successful treatment 11 (14.66% patients had recurrent attack of BPPV during the first year. Conclusion. The Epley maneuver is very successful repositioning procedure in treating p- BPPV. The patients with idiopathic form p-BPPV showed higher success rate with Epley maneuver than those with secondary p-BPPV.

  14. Traumatic rupture of Ionescu-Shiley aortic valve after the Heimlich maneuver.

    Science.gov (United States)

    Passik, C S; Ackermann, D M; Piehler, J M; Edwards, W D

    1987-05-01

    A 74-year-old woman who had undergone aortic valve replacement with an Ionescu-Shiley bioprosthesis was evaluated and treated because aortic insufficiency developed after the application of the Heimlich maneuver. Pathologic examination of the explanted valve disclosed a cuspid perforation and an adjacent tear of a second cusp at its insertion into the valve strut. Patients with unexplained acute prosthetic insufficiency should be questioned as to whether the Heimlich maneuver has been previously performed.

  15. Braking News: the Link between Crash Severity and Crash Avoidance Maneuvers

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2012-01-01

    avoidance maneuvers and crash severity, with differences emerging for different critical events. Moreover, results show two trends: (i) most drivers fail to act when facing critical events, and (ii) drivers rarely perform crash avoidance maneuvers that are correlated with higher probability of lower crash...... severity. These trends suggest that effort should be posed toward understanding the reaction mechanisms to different critical events, improving in-vehicle warning systems, promoting responsible driving behavior, and designing forgiving infrastructures....

  16. Effects of bronchomotor tone and gas density on time dependence of forced expiratory vital capacity maneuver.

    Science.gov (United States)

    D'Angelo, E; Milic-Emili, J; Marazzini, L

    1996-11-01

    It has been shown that in normal subjects and chronic obstructive pulmonary disease (COPD) patients the maximal expiratory flows and FEV1 are significantly higher if the FVC maneuver is preceded by a rapid inspiration without an end-inspiratory pause (maneuver 1) compared with a slow inspiration with an end-inspiratory pause of approximately 5 s (maneuver 2). This time dependency of FVC was attributed primarily to loss of lung recoil (stress relaxation) during breath-holding at TLC, in association with time constant inequality within the lungs, and changes in bronchomotor tone. To examine the role of bronchomotor tone on time dependency of FVC, 11 COPD and 10 asthmatic patients performed FVC maneuvers 1 and 2 before and after administration of a bronchodilator drug (salbutamol). In addition, using the same approach, the effects of changing airway resistance per se were assessed in another group of 10 COPD patients and 10 normal subjects, while breathing air and after equilibration with 80% helium in oxygen. Main findings were: peak expiratory flow (PEF), FEV1, and maximal midexpiratory flow rate (MMF) were significantly larger with maneuver 1 than 2; after salbutamol administration and during helium-oxygen breathing, all indices increased significantly with both maneuvers but the relative differences between maneuvers 1 and 2 were unchanged. We conclude that time dependency of maximal expiratory flow-volume (MEFV) curves, as indexed by PEF, FEV1, and MMF, is largely independent of bronchomotor tone and gas density, and probably reflects mainly stress relaxation of the respiratory tissues. The relevance of time dependency of FVC maneuver in the assessment of bronchodilator response and density dependence is discussed.

  17. Energy-balanced multiple-sensor collaborative scheduling for maneuvering target tracking in wireless sensor networks

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    An energy-balanced multiple-sensor collaborative scheduling is proposed for maneuvering target tracking in wireless sensor networks (WSNs). According to the position of the maneuvering target, some sensor nodes in WSNs are awakened to form a sensor cluster for target tracking collaboratively. In the cluster, the cluster head node is selected to implement tracking task with changed sampling interval. The distributed interactive multiple model (IMM) filter is employed to estimate the target state. The estimat...

  18. The potential role of epigenetic modulations in BPPV maneuver exercises.

    Science.gov (United States)

    Tsai, Kun-Ling; Wang, Chia-To; Kuo, Chia-Hua; Cheng, Yuan-Yang; Ma, Hsin-I; Hung, Ching-Hsia; Tsai, Yi-Ju; Kao, Chung-Lan

    2016-06-14

    Benign paroxysmal positional vertigo (BPPV) is one of the most common complaints encountered in clinics and is strongly correlated with advanced age or, possibly, degeneration. Redistribution exercises are the most effective approaches to treat BPPV, and canalith repositioning procedure (CRP) cure most BPPV cases. However, the mechanisms through which the treatment modulates systemic molecules in BPPV patients remain largely unknown. In this study, we report that the miR-34a and Sirtuin 1 (SIRT1) genes correlated with the treatment effects of CRP in BPPV subjects. We found that miR-34a expression was largely inhibited and SIRT1 expression was significantly reversed after BPPV maneuver treatment. We also confirmed that the PPAR-γ, PGC-1 and FoxO gene expressions were decreased immediately after canalith repositioning procedure (CRP) for BPPV, and were largely increased after a complete cure of BPPV. Moreover, we observed that after a complete recovery of BPPV, the ROS concentrations, pro-inflammatory cytokine concentrations and p53 expression levels were attenuated. We conclude that BPPV treatment might involve some epigenetic regulations through the mediation of miR-34a, SIRT1 functions and repression of redox status.

  19. Atmospheric environment during maneuvering descent from Martian orbit

    Science.gov (United States)

    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.

  20. The potential role of epigenetic modulations in BPPV maneuver exercises

    Science.gov (United States)

    Tsai, Kun-Ling; Wang, Chia-To; Kuo, Chia-Hua; Cheng, Yuan-Yang; Ma, Hsin-I; Hung, Ching-Hsia; Tsai, Yi-Ju; Kao, Chung-Lan

    2016-01-01

    Benign paroxysmal positional vertigo (BPPV) is one of the most common complaints encountered in clinics and is strongly correlated with advanced age or, possibly, degeneration. Redistribution exercises are the most effective approaches to treat BPPV, and canalith repositioning procedure (CRP) cure most BPPV cases. However, the mechanisms through which the treatment modulates systemic molecules in BPPV patients remain largely unknown. In this study, we report that the miR-34a and Sirtuin 1 (SIRT1) genes correlated with the treatment effects of CRP in BPPV subjects. We found that miR-34a expression was largely inhibited and SIRT1 expression was significantly reversed after BPPV maneuver treatment. We also confirmed that the PPAR-γ, PGC-1 and FoxO gene expressions were decreased immediately after canalith repositioning procedure (CRP) for BPPV, and were largely increased after a complete cure of BPPV. Moreover, we observed that after a complete recovery of BPPV, the ROS concentrations, pro-inflammatory cytokine concentrations and p53 expression levels were attenuated. We conclude that BPPV treatment might involve some epigenetic regulations through the mediation of miR-34a, SIRT1 functions and repression of redox status. PMID:27203679

  1. MEMS Reaction Control and Maneuvering for Picosat Beyond LEO

    Science.gov (United States)

    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.

  2. Tactical approach to maneuvering within the chemical contamination labyrinth

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, T.W. [Department of Energy, Oak Ridge, TN (United States)

    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.

  3. Spacecraft Attitude Tracking and Maneuver Using Combined Magnetic Actuators

    Science.gov (United States)

    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.

  4. Heading Lock Maneuver Testing of Autonomous Underwater Vehicle

    CERN Document Server

    Muljowidodo, K

    2008-01-01

    In recent years, Autonomous Underwater Vehicle (UAV) research and development at Bandung Institute of Technology in Indonesia has achieved the testing stage in the field. This testing was still being classified as the early testing, since some of the preliminary tests were carried out in the scale of the laboratory. The paper would discuss the laboratory test and several tests that were done in the field. Discussions were stressed in the procedure and the aim that will be achieved, along with several early results. The testing was carried out in the lake with the area around 8300 Ha and the maximum depth of 50 meters. The location of the testing was chosen with consideration of minimizing the effect of the current and the wave, as well as the location that was not too far from the Laboratory. The type of testing that will be discussed in paper was Heading Lock Maneuver Testing. The vehicle was tested to move with a certain cruising speed, afterwards it was commanded by an arbitrarily selected heading directio...

  5. Epley's Maneuver in Benign Paroxysmal Positional Vertigo: Series of Cases Reports

    Directory of Open Access Journals (Sweden)

    Marchiori, Luciana Lozza de Moraes

    2011-04-01

    Full Text Available Introduction: Benign paroxysmal positional vertigo (BPPV is probably the most common cause of vertigo in women. Objective: To report the result of Epley's maneuver when treating BPPV patients. Method: Study of a series of 9-month-long cases of five female individuals aged between 46 and 64 with BPPV, who were submitted to Epley's maneuver at a scholar clinics, having the positive Dix-Hallpike maneuver at the first consultation as an inclusion criterion, and evaluations were repeated in a six and nine-month term. Results: Only one Epley's maneuver, as the only therapeutic procedure, was enough to eliminate nystagmus and positional vertigo in 4 patients, who did not show a positive Dix-Hallpike maneuver in the two reevaluations performed. Only one patient showed BPPV in the first reevaluation of the study term, and nystagmus reoccurred in the second evaluation only. Conclusion: Epley's repositioning maneuver proved to be a simple and effective BPPV treatment method for this study's patients at length.

  6. Effect of width and boundary conditions on meeting maneuvers on two-way separated cycle tracks.

    Science.gov (United States)

    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.

  7. Anterior Displacement of Lamina Cribrosa during Valsalva Maneuver in Young Healthy Eyes.

    Directory of Open Access Journals (Sweden)

    Yong Woo Kim

    Full Text Available To investigate lamina cribrosa (LC displacement during the Valsalva maneuver in young healthy eyes using enhanced depth imaging (EDI spectral-domain optical coherence tomography (SD-OCT.Forty-eight eyes of 48 young healthy volunteers (age range: 20-34 years underwent intraocular pressure (IOP measurement by Goldmann applanation tonometry as well as Cirrus HD-OCT scans before and during the Valsalva maneuver. The optic nerve head (ONH parameters (average retinal nerve fiber layer thickness, rim area, disc area, average C/D ratio, vertical C/D ratio, cup volume, anterior LC depth (LCD, subfoveal and peripapillary choroidal thickness, and neural canal opening diameter were measured on compensated OCT and compared during Valsalva challenge. The subjects were asked to take a five-minute break after each Valsalva maneuver.During the Valsalva maneuver, the IOP significantly increased, from 12.7 ± 3.0 mmHg to 16.0 ± 3.2 mmHg (P 0.05.The Valsalva maneuver induced anterior displacement of the LC, but did not alter the choroidal thickness or ONH morphology. The data describe the positional characteristics of the LC in response to the Valsalva maneuver in young healthy eyes.

  8. Betting against Beta

    DEFF Research Database (Denmark)

    Frazzini, Andrea; Heje Pedersen, Lasse

    2014-01-01

    We present a model with leverage and margin constraints that vary across investors and time. We find evidence consistent with each of the model's five central predictions: (1) Because constrained investors bid up high-beta assets, high beta is associated with low alpha, as we find empirically for......, the return of the BAB factor is low. (4) Increased funding liquidity risk compresses betas toward one. (5) More constrained investors hold riskier assets....... for US equities, 20 international equity markets, Treasury bonds, corporate bonds, and futures. (2) A betting against beta (BAB) factor, which is long leveraged low-beta assets and short high-beta assets, produces significant positive risk-adjusted returns. (3) When funding constraints tighten...

  9. Betting Against Beta

    DEFF Research Database (Denmark)

    Frazzini, Andrea; Heje Pedersen, Lasse

    We present a model with leverage and margin constraints that vary across investors and time. We find evidence consistent with each of the model’s five central predictions: (1) Since constrained investors bid up high-beta assets, high beta is associated with low alpha, as we find empirically for U...... of the BAB factor is low; (4) Increased funding liquidity risk compresses betas toward one; (5) More constrained investors hold riskier assets........S. equities, 20 international equity markets, Treasury bonds, corporate bonds, and futures; (2) A betting-against-beta (BAB) factor, which is long leveraged low beta assets and short high-beta assets, produces significant positive risk-adjusted returns; (3) When funding constraints tighten, the return...

  10. A multistate life table approach to understanding return and reentry migration between Mexico and the United States during later life

    Directory of Open Access Journals (Sweden)

    Alma Vega

    2015-12-01

    Full Text Available Background: Empirical research describes retirement migration to Mexico as a viable option for some older Americans. However, far less research examines this phenomenon among Mexican immigrants in the United States. The literature that does address this topic treats international migration as a singular occurrence and does not examine the possibility of return and subsequent reentry between countries. This omission creates an important gap in our knowledge of international retirement migration, considering the strong transnational ties that Mexican immigrants maintain to their home and destination countries. Objective: Using a multistate life table approach, this study examines the rate of return to Mexico and reentry back into the United States among Mexican males aged 50 and older with U.S. migration experience, as well as the number of years spent in both countries. Results: Results show that the rate of reentry from Mexico into the United States declined from 3.33Š at ages 50-54 to less than 1Š at age 70 and older (pConclusions: Although rates of return and reentry among this population are relatively low, they provide insight into the potential life course factors driving the migration patterns of a population of increasing size and relevance in the United States.

  11. Does Offender Gambling on the inside Continue on the outside? Insights from Correctional Professionals on Gambling and Re-Entry

    Science.gov (United States)

    Williams, D. J.; Walker, Gordon J.

    2009-01-01

    This study brings to light a neglected topic of particular importance--offender gambling issues within the context of re-entry into the community. Fifteen correctional professionals from Nevada (high gambling availability) and Utah (no legalized gambling) participated in semi-structured interviews to provide insights into how gambling may impact…

  12. Use of the Stingray Re-Entry System in Two Complex Cases of Occluded Superficial Femoral Arteries

    OpenAIRE

    Galbraith, Erin M.; Marc Del Rosario; Khusrow Niazi

    2011-01-01

    Totally occluded infrainguinal arterial disease presents formidable challenges to endovascular revascularization. A variety of devices have been made available to make the crossing of these lesions more amenable to endovascular techniques. We discuss the novel use of a device that has been developed for crossing occluded coronary arteries, the Stingray Re-Entry System.

  13. Use of the Stingray Re-Entry System in Two Complex Cases of Occluded Superficial Femoral Arteries

    Directory of Open Access Journals (Sweden)

    Erin M. Galbraith

    2011-01-01

    Full Text Available Totally occluded infrainguinal arterial disease presents formidable challenges to endovascular revascularization. A variety of devices have been made available to make the crossing of these lesions more amenable to endovascular techniques. We discuss the novel use of a device that has been developed for crossing occluded coronary arteries, the Stingray Re-Entry System.

  14. FGF1-mediated cardiomyocyte cell cycle reentry depends on the interaction of FGFR-1 and Fn14.

    Science.gov (United States)

    Novoyatleva, Tatyana; Sajjad, Amna; Pogoryelov, Denys; Patra, Chinmoy; Schermuly, Ralph T; Engel, Felix B

    2014-06-01

    Fibroblast growth factors (FGFs) signal through FGF receptors (FGFRs) mediating a broad range of cellular functions during embryonic development, as well as disease and regeneration during adulthood. Thus, it is important to understand the underlying molecular mechanisms that modulate this system. Here, we show that FGFR-1 can interact with the TNF receptor superfamily member fibroblast growth factor-inducible molecule 14 (Fn14) resulting in cardiomyocyte cell cycle reentry. FGF1-induced cell cycle reentry in neonatal cardiomyocytes could be blocked by Fn14 inhibition, while TWEAK-induced cell cycle activation was inhibited by blocking FGFR-1 signaling. In addition, costimulation experiments revealed a synergistic effect of FGF1 and TWEAK in regard to cardiomyocyte cell cycle induction via PI3K/Akt signaling. Overexpression of Fn14 with either FGFR-1 long [FGFR-1(L)] or FGFR-1 short [FGFR-1(S)] isoforms resulted after FGF1/TWEAK stimulation in cell cycle reentry of >40% adult cardiomyocytes. Finally, coimmunoprecipitation and proximity ligation assays indicated that endogenous FGFR-1 and Fn14 interact with each other in cardiomyocytes. This interaction was strongly enhanced in the presence of their corresponding ligands, FGF1 and TWEAK. Taken together, our data suggest that FGFR-1/Fn14 interaction may represent a novel endogenous mechanism to modulate the action of these receptors and their ligands and to control cardiomyocyte cell cycle reentry.

  15. Vocational Interest as a Correlate of Re-Entry of Girls into School in Edo State, Nigeria: Implications for Counselling

    Science.gov (United States)

    Alika, Ijeoma Henrietta; Egbochuku, Elizabeth Omotunde

    2012-01-01

    The study investigated the relationship between vocational interest socio-economic status and re-entry of girls into school in Edo State. The research design adopted was correlational because it sought to establish the relationship between the independent variable and the dependent variable. A sample size of 306 girls who re-enrolled in institutes…

  16. A Leadership Opportunity for School Social Workers: Bridging the Gaps in School Reentry for Juvenile Justice System Youths

    Science.gov (United States)

    Goldkind, Lauri

    2011-01-01

    Social work is frequently missing when policy and practice conversations turn to juvenile justice system youths. However, school social workers are well positioned to have a vital role in the readmission and reentry process for these young people. Formerly incarcerated youths present unique challenges for themselves, their families, and…

  17. The Role of Counselling and Parental Encouragement on Re-Entry of Adolescents into Secondary Schools in Abia State, Nigeria

    Science.gov (United States)

    Alika, Henrietta Ijeoma; Ohanaka, Blessing Ijeoma

    2013-01-01

    This paper examined the role of counselling, and parental encouragement on re-entry of adolescents into secondary school in Abia State, Nigeria. A total of 353 adolescents who re-entered school were selected from six secondary schools in the State through a simple random sampling technique. A validated questionnaire was used for data analysis.…

  18. A Qualitative Investigation of the College Choice Experiences and Reentry Expectations of U.S. American Third Culture Kids

    Science.gov (United States)

    Thurston-Gonzalez, Sara J.

    2009-01-01

    The focus of this qualitative study is on U.S. third culture kids (TCKs), youth who have grown up abroad because of their parent's work, and their college choice experiences and reentry expectations. Through a background questionnaire and personal interviews with eleven students transitioning from two international secondary schools in a…

  19. An Exploration of Factors Reducing Recidivism Rates of Formerly Incarcerated Youth with Disabilities Participating in a Re-Entry Intervention

    Science.gov (United States)

    Unruh, Deanne K.; Gau, Jeff M.; Waintrup, Miriam G.

    2009-01-01

    Juvenile offenders are costly to our society in terms of the monetary and social expenditures from the legal system, victims' person costs, and incarceration. The re-entry and community reintegration outcomes for formerly incarcerated youth with a disabling condition are bleak compared to peers without disabilities. In this study, we examined the…

  20. Imperfect World of $\\beta\\beta$-decay Nuclear Data Sets

    CERN Document Server

    Pritychenko, B

    2015-01-01

    The precision of double-beta ($\\beta\\beta$) decay experimental half lives and their uncertainties is reanalyzed. The method of Benford's distributions has been applied to nuclear reaction, structure and decay data sets. First-digit distribution trend for $\\beta\\beta$-decay T$_{1/2}^{2\

  1. Investigating a Novel Activation-Repolarisation Time Metric to Predict Localised Vulnerability to Reentry Using Computational Modelling.

    Science.gov (United States)

    Hill, Yolanda R; Child, Nick; Hanson, Ben; Wallman, Mikael; Coronel, Ruben; Plank, Gernot; Rinaldi, Christopher A; Gill, Jaswinder; Smith, Nicolas P; Taggart, Peter; Bishop, Martin J

    2016-01-01

    Exit sites associated with scar-related reentrant arrhythmias represent important targets for catheter ablation therapy. However, their accurate location in a safe and robust manner remains a significant clinical challenge. We recently proposed a novel quantitative metric (termed the Reentry Vulnerability Index, RVI) to determine the difference between activation and repolarisation intervals measured from pairs of spatial locations during premature stimulation to accurately locate the critical site of reentry formation. In the clinic, the method showed potential to identify regions of low RVI corresponding to areas vulnerable to reentry, subsequently identified as ventricular tachycardia (VT) circuit exit sites. Here, we perform an in silico investigation of the RVI metric in order to aid the acquisition and interpretation of RVI maps and optimise its future usage within the clinic. Within idealised 2D sheet models we show that the RVI produces lower values under correspondingly more arrhythmogenic conditions, with even low resolution (8 mm electrode separation) recordings still able to locate vulnerable regions. When applied to models of infarct scars, the surface RVI maps successfully identified exit sites of the reentrant circuit, even in scenarios where the scar was wholly intramural. Within highly complex infarct scar anatomies with multiple reentrant pathways, the identified exit sites were dependent upon the specific pacing location used to compute the endocardial RVI maps. However, simulated ablation of these sites successfully prevented the reentry re-initiation. We conclude that endocardial surface RVI maps are able to successfully locate regions vulnerable to reentry corresponding to critical exit sites during sustained scar-related VT. The method is robust against highly complex and intramural scar anatomies and low resolution clinical data acquisition. Optimal location of all relevant sites requires RVI maps to be computed from multiple pacing

  2. Investigating a Novel Activation-Repolarisation Time Metric to Predict Localised Vulnerability to Reentry Using Computational Modelling.

    Directory of Open Access Journals (Sweden)

    Yolanda R Hill

    Full Text Available Exit sites associated with scar-related reentrant arrhythmias represent important targets for catheter ablation therapy. However, their accurate location in a safe and robust manner remains a significant clinical challenge. We recently proposed a novel quantitative metric (termed the Reentry Vulnerability Index, RVI to determine the difference between activation and repolarisation intervals measured from pairs of spatial locations during premature stimulation to accurately locate the critical site of reentry formation. In the clinic, the method showed potential to identify regions of low RVI corresponding to areas vulnerable to reentry, subsequently identified as ventricular tachycardia (VT circuit exit sites. Here, we perform an in silico investigation of the RVI metric in order to aid the acquisition and interpretation of RVI maps and optimise its future usage within the clinic. Within idealised 2D sheet models we show that the RVI produces lower values under correspondingly more arrhythmogenic conditions, with even low resolution (8 mm electrode separation recordings still able to locate vulnerable regions. When applied to models of infarct scars, the surface RVI maps successfully identified exit sites of the reentrant circuit, even in scenarios where the scar was wholly intramural. Within highly complex infarct scar anatomies with multiple reentrant pathways, the identified exit sites were dependent upon the specific pacing location used to compute the endocardial RVI maps. However, simulated ablation of these sites successfully prevented the reentry re-initiation. We conclude that endocardial surface RVI maps are able to successfully locate regions vulnerable to reentry corresponding to critical exit sites during sustained scar-related VT. The method is robust against highly complex and intramural scar anatomies and low resolution clinical data acquisition. Optimal location of all relevant sites requires RVI maps to be computed from

  3. Gravity wave and tidal structures between 60 and 140 km inferred from space shuttle reentry data

    Science.gov (United States)

    Fritts, David C.; Wang, Ding-Yi; Blanchard, Robert C.

    1993-01-01

    This study presents an analysis of density measurements made using high-resolution accelerometers aboard several space shuttles at altitudes from 60 to 140 km during reentry into the earth's atmosphere. The observed density fluctuations are interpreted in terms of gravity waves and tides and provide evidence of the importance of such motions well into the thermosphere. Height profiles of fractional density variance reveal that wave amplitudes increase at a rate consistent with observations at lower levels up to about 90 km. The rate of amplitude growth decreases at greater heights, however, and appears to cease above about 110 km. Wave amplitudes are nevertheless large at these heights and suggest that gravity waves may play an important role in forcing of the lower thermosphere.

  4. Supraventricular tachycardia in Lown-Ganong-Levine syndrome: atrionodal versus intranodal reentry.

    Science.gov (United States)

    Josephson, M E; Kastor, J A

    1977-10-01

    The mechanism of the abbreviated atrioventricular (A-V) nodal conduction time and paroxysmal supraventricular tachycardia in the Lown-Ganong-Levine syndrome was evaluated in six patients. In each the A-H interval increased in response to rapid atrial pacing and atrial extrastimuli; typical dual A-V nodal pathways were demonstrated. In five patients studied at two cycle lengths prolongation of conduction and refractoriness of the "fast" pathway was noted at the shorter basic cycle length. Propranolol prolonged conduction and refractoriness of the "fast" pathway in three patients and in one produced Wenckebach conduction during atrial pacing which did not occur prior to its administration. In three patients the atrium did not appear necessary to sustain supraventricular tachycardia. These findings suggest that preferential rapidly conducting A-V nodal fibers and intranodal reentry are the responsible mechanisms in those patients with Lown-Ganong-Levine syndrome and reciprocating tachycardia.

  5. Social bonds and change during incarceration: testing a missing link in the reentry research.

    Science.gov (United States)

    Rocque, Michael; Bierie, David M; MacKenzie, Doris L

    2011-08-01

    Research examining prisoner reentry has demonstrated negative impacts of incarceration on social bonds. However, this research is limited in two ways. First, it generally examines outcomes after release, paying less attention to processes occurring in prison. Second, this work tends to examine "incarceration" as a whole, regarding prisons as homogenous. This study uses data from an experiment in which offenders were randomly assigned to incarceration at one of two prisons polarized across a number of structural characteristics that research suggests affect social bonds (a traditional prison vs. a correctional boot camp). Groups were compared with respect to commitment, belief, attachment, and in terms of changes among their relationships during incarceration. The data showed that the boot camp improved prosocial beliefs, but few differences emerged in terms of commitment and attachment. Similarly, the data showed few differences in attachment regardless of the prosocial or antisocial orientation of the inmate's friends or family.

  6. A small-gain method for integrated guidance and control in terminal phase of reentry

    Science.gov (United States)

    Yan, Han; Tan, Shuping; He, Yingzi

    2017-03-01

    The guidance and control systems of reentry vehicles are usually designed separately and then integrated, but the scheme can be argued that synergistic relationships between the two subsystems are not fully exploited. In order to improve the performance of reusable launch vehicles (RLVs), this paper proposes an integrated guidance and control law for approach and landing of a RLV. According to the idea of reference-trajectory guidance, the angle of attack and bank angle commands are designed using sliding mode control (SMC) method to make the reference-trajectory tacking error converge into a small neighborhood of zero. An integrated guidance and control (IGC) law is developed utilizing generalized small-gain theorem to enforce the commands, and theoretical analysis shows that the law can guarantee the stability of the overall system. The Monte Carlo simulation confirms the effectiveness of the proposed design approach.

  7. A Study on Missile Reentry Control Based on the Method of Feedback Linearization

    Institute of Scientific and Technical Information of China (English)

    LIU Yu-xi; ZHOU Jun; ZHOU Feng-qi

    2007-01-01

    In the process of missile large attack angle reentry, there exist nonlinear, strong coupling uncertainty and multiinput-multi-output (MIMO) in the movement equations, so the traditional small disturbance faces difficulties. For such situations, the method of feedback linearization is adopted to control the complex system, and the control method based on the fuzzy adaptive nonlinear dynamic inversion decoupling control of missile is proposed in the paper. According to the principle of time-scale separation, the system is separated into fast loop and slow loop, the method of dynamic inversion is applied to them, and the method of adaptive fuzzy approach is adopted to compensate for the uncertainty of the fast loop.The simulation results denote the control method in the paper has a better tracing characteristic and robustness.

  8. Ceramic Adhesive and Methods for On-Orbit Repair of Re-Entry Vehicles

    Science.gov (United States)

    Riedell, James A.; Easler, Timothy E.

    2013-01-01

    This adhesive is capable of repairing damaged leading edge components of reentry vehicles while in space, and is novel with regard to its ability to be applied in the vacuum of space, and in a microgravity environment. Once applied, the adhesive provides thermal and oxidation protection to the substrate (in this case, reinforced carbon/carbon composites, RCCs) during re-entry of a space vehicle. Although there may be many formulations for repair adhesives, at the time of this reporting, this is the first known adhesive capable of an on-orbit repair. The adhesive is an engineered ceramic material composed of a pre-ceramic polymer and refractory powders in the form of a paste or putty that can be applied to a scratched, cracked, or fractured composite surface, covering and protecting the damaged area. The adhesive is then "cured" with a heat cycle, thereby cross-linking the polymer into a hardened material and bonding it to the substrate. During the heat of reentry, the material is converted to a ceramic coating that provides thermal and oxidative stability to the repaired area, thus allowing the vehicle to pass safely from space into the upper atmosphere. Ceramic powders such as SiC, ZrB2 and Y2O3 are combined with allylhydridopolycarbosilane (AHPCS) resin, and are mixed to form a paste adhesive. The material is then applied to the damaged area by brush, spatula, trowel, or other means to fill cracks, gaps, and holes, or used to bond patches onto the damaged area. The material is then cured, in a vacuum, preferably at 250F (approximately equal to 121C) for two hours. The re-entry heating of the vehicle at temperatures in excess of 3,000F (approximately equal to 1,650C) then converts this material into a ceramic coating. This invention has demonstrated advantages in resistance to high temperatures, as was demonstrated in more than 100 arc-jet tests in representative environments at NASA. Extensive testing verified oxidation protection for the repaired substrate (RCC

  9. Daytime Locations in Spatial Mismatch: Job Accessibility and Employment at Reentry From Prison.

    Science.gov (United States)

    Sugie, Naomi F; Lens, Michael C

    2017-04-01

    Individuals recently released from prison confront many barriers to employment. One potential obstacle is spatial mismatch-the concentration of low-skilled, nonwhite job-seekers within central cities and the prevalence of relevant job opportunities in outlying areas. Prior research has found mixed results about the importance of residential place for reentry outcomes. In this article, we propose that residential location matters for finding work, but this largely static measure does not capture the range of geographic contexts that individuals inhabit throughout the day. We combine novel, real-time GPS information on daytime locations and self-reported employment collected from smartphones with sophisticated measures of job accessibility to test the relative importance of spatial mismatch based on residence and daytime locations. Our findings suggest that the ability of low-skilled, poor, and urban individuals to compensate for their residential deficits by traveling to job-rich areas is an overlooked and salient consideration in spatial mismatch perspectives.

  10. Objective Evaluation Method of Steering Comfort Based on Movement Quality Evaluation of Driver Steering Maneuver

    Institute of Scientific and Technical Information of China (English)

    YANG Yiyong; LIU Yahui; WANG Man; JI Run; JI Xuewu

    2014-01-01

    The existing research of steering comfort mainly focuses on the subjective evaluation, aiming at designing and optimizing the steering system. In the development of steering system, especially the evaluation of steering comfort, the objective evaluation methods considered the kinematic characteristics of driver steering maneuver are not proposed, which means that the objective evaluation of steering cannot be conducted with the evaluation of kinematic characteristics of driver in steering maneuver. In order to propose the objective evaluation methods of steering comfort, the evaluation of steering movement quality of driver is developed on the basis of the study of the kinematic characteristics of steering maneuver. First, the steering motion trajectories of the driver in both comfortable and certain extreme uncomfortable operation conditions are detected using the Vicon motion capture system. The operation conditions are under the restrictions of the vertical height and horizontal distance between steering wheel center and the H-point of driver, and the steering resisting torque else. Next, the movement quality evaluation of driver steering maneuver is assessed using twelve kinds of evaluation indices based on the kinematic analyses of the steering motion trajectories to propose an objective evaluation method. Finally, an integrated discomfort index of steering maneuver is proposed on the basis of the regression analysis of subjective evaluation rating and the movement quality evaluation indices, including the Jerk, Discomfort and Joint Torque indices. The test results show that the proposed integrated discomfort index gives a good fitting with the subjective evaluation of discomfort, which means it can be used to evaluate or predict the discomfort level of steering maneuver. This paper proposes an objective evaluation method of steering comfort based on the movement quality evaluation of driver steering maneuver.

  11. Comparison of Mallampati test with lower jaw protrusion maneuver in predicting difficult laryngoscopy and intubation

    Directory of Open Access Journals (Sweden)

    Muhammad Irfan Ul Haq

    2013-01-01

    Full Text Available Background: Failure to maintain a patent airway is one of the commonest causes of anesthesia-related morbidity and mortality. Many protocols, algorithms, and different combinations of tested methods for airway assessment have been developed to predict difficult laryngoscopy and intubation. The reported incidence of a difficult intubation varies from 1.5% to 13%. The objective of this study was to compare Mallampati test (MT with lower jaw protrusion (LJP maneuver in predicting difficult laryngoscopy and intubation. Materials and Methods: Seven hundred and sixty patients were included in the study. All the patients underwent MT and LJP maneuver for their airway assessment. After a standardized technique of induction of anesthesia, primary anesthetist performed laryngoscopy and graded it according to the grades described by Cormack and Lehane. Sensitivity, specificity, accuracy, and positive predictive value (PPV and negative predictive value (NPV were calculated for both these tests with 95% confidence interval (CI using conventional laryngoscopy as gold standard. Area under curve was also calculated for both, MT and LJP maneuver. A P < 0.05 was taken as significant. Results: LJP maneuver had higher sensitivity (95.9% vs. 27.1%, NPV (98.7% vs. 82.0%, and accuracy (90.1% vs. 80.3% when compared to MT in predicting difficult laryngoscopy and intubation. Both tests, however, had similar specificity and PPV. There was marked difference in the positive and negative likelihood ratio between LJP and MT. Similarly, the area under the curve favored LJP maneuver over MT. Conclusion: The results of this study show that LJP maneuver is a better test to predict difficult laryngoscopy and tracheal intubation. We recommend the addition of this maneuver to the routine preoperative evaluation of airway.

  12. The use of the Heimlich maneuver in near drowning: Institute of Medicine report.

    Science.gov (United States)

    Rosen, P; Stoto, M; Harley, J

    1995-01-01

    The application of the Heimlich maneuver as the initial and perhaps only step for opening the airway in all near-drowning victims has been proposed by Henry Heimlich and Edward Patrick, contrary to current resuscitation guidelines for the treatment of near-drowning victims established by the Emergency Cardiac Care (ECC) Committee of the American Heart Association. Although the Heimlich maneuver is useful for the removal of aspirated solid foreign bodies, there is no evidence that death from drowning is frequently caused by aspiration of a solid foreign body that is not effectively treated by the current ECC recommendations. Furthermore, the evidence is insufficient to support the proposition that the Heimlich maneuver is useful for the removal of aspirated liquid. Moreover, because there is no evidence to support Heimlich's hypothesis that substantial amounts of water are aspirated by near-drowning victims or that such aspirated liquid causes brain damage and death, the available evidence does not support routine use of the Heimlich maneuver in the care of near-drowning victims. The routine use of the Heimlich maneuver for treatment of near drowning raises several concerns: (a) the amount of time it would take to repeat this maneuver and how long this would delay the initiation of artificial ventilation; (b) possible complications of the Heimlich maneuver, especially if the near drowning is associated with a cervical fracture; and (c) the prospect of teaching rescue workers a different protocol than that which is taught at present for resuscitating victims of cardiopulmonary arrest from all causes other than near drowning.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Negative Beta Encoder

    CERN Document Server

    Kohda, Tohru; Aihara, Kazuyuki

    2008-01-01

    A new class of analog-digital (A/D), digital-analog (D/A) converters as an alternative to conventional ones, called $\\beta$-encoder, has been shown to have exponential accuracy in the bit rates while possessing self-correction property for fluctuations of amplifier factor $\\beta$ and quantizer threshold $\

  14. Double beta decay experiments

    CERN Document Server

    Barabash, A S

    2011-01-01

    The present status of double beta decay experiments is reviewed. The results of the most sensitive experiments are discussed. Proposals for future double beta decay experiments with a sensitivity to the $$ at the level of (0.01--0.1) eV are considered.

  15. Genetics Home Reference: beta thalassemia

    Science.gov (United States)

    ... Understand Genetics Home Health Conditions beta thalassemia beta thalassemia Enable Javascript to view the expand/collapse boxes. Download PDF Open All Close All Description Beta thalassemia is a blood disorder that reduces the production ...

  16. Rapid synthesis of beta zeolites

    Science.gov (United States)

    Fan, Wei; Chang, Chun -Chih; Dornath, Paul; Wang, Zhuopeng

    2015-08-18

    The invention provides methods for rapidly synthesizing heteroatom containing zeolites including Sn-Beta, Si-Beta, Ti-Beta, Zr-Beta and Fe-Beta. The methods for synthesizing heteroatom zeolites include using well-crystalline zeolite crystals as seeds and using a fluoride-free, caustic medium in a seeded dry-gel conversion method. The Beta zeolite catalysts made by the methods of the invention catalyze both isomerization and dehydration reactions.

  17. Multiple Maneuvering Target Tracking by Improved Particle Filter Based on Multiscan JPDA

    Directory of Open Access Journals (Sweden)

    Jing Liu

    2012-01-01

    Full Text Available The multiple maneuvering target tracking algorithm based on a particle filter is addressed. The equivalent-noise approach is adopted, which uses a simple dynamic model consisting of target state and equivalent noise which accounts for the combined effects of the process noise and maneuvers. The equivalent-noise approach converts the problem of maneuvering target tracking to that of state estimation in the presence of nonstationary process noise with unknown statistics. A novel method for identifying the nonstationary process noise is proposed in the particle filter framework. Furthermore, a particle filter based multiscan Joint Probability Data Association (JPDA filter is proposed to deal with the data association problem in a multiple maneuvering target tracking. In the proposed multiscan JPDA algorithm, the distributions of interest are the marginal filtering distributions for each of the targets, and these distributions are approximated with particles. The multiscan JPDA algorithm examines the joint association events in a multiscan sliding window and calculates the marginal posterior probability based on the multiscan joint association events. The proposed algorithm is illustrated via an example involving the tracking of two highly maneuvering, at times closely spaced and crossed, targets, based on resolved measurements.

  18. Is it important to repeat the positioning maneuver after the treatment for benign paroxysmal positional vertigo?

    Directory of Open Access Journals (Sweden)

    Alexandra Kolontai de Sousa Oliveira

    2015-04-01

    Full Text Available INTRODUCTION: Benign paroxysmal positional vertigo (BPPV is the most common cause of peripheral vestibular dysfunction.OBJECTIVE: To assess whether the performance of the Dix-Hallpike maneuver after the Epley positioning maneuver has prognostic value in the evolution of unilateral ductolithiasis of posterior semicircular canal.METHODS: A prospective cohort study in monitored patients at otoneurology ambulatory with a diagnosis of BPPV; they were submitted to the therapeutic maneuver and then to a retest in order to evaluate the treatment effectiveness; all cases were reassessed one week later and the retest prognostic value was evaluated.RESULTS: A sample of 64 patients which 47 belonging to negative retest group and 17 belonging to positive retest. Performed the maneuver in all patients, the retest presented 51.85% sensitivity, 91.89% specificity, 82.35% positive predictive value and 72.34% negative predictive value.CONCLUSION: The study shows that doing the retest after repositioning maneuver of particles in BPPV is effectual, since it has high specificity.

  19. Variables Affecting Canalith Repositioning Maneuver (CRM Trend for Treating Patients with Benign Paroxysmal Positional Vertigo (BPPV

    Directory of Open Access Journals (Sweden)

    E. Entezari

    2006-07-01

    Full Text Available Background: The purpose of this study was to identify variables affecting outcome in patients with benign paroxysmal positional vertigo (BPPV treated with canalith repositioning maneuver (CRM. Methods: This interventional study was conducted on 58 patients (14 males, 44 females, mean age 48.12+13.22 referred to the Vertigo Rehabilitation Clinic of the Rehabilitation School of Tehran University of Medical Sciences from 2002 to 2004. All patients were treated with CRM. According to the treatment efficacy the patients were allocated in three groups: completely treated, partially treated, and not treated. The effect of factors including age, sex, etiology, duration of BPPV, unilateral or bilateral disease, number of maneuvers, and number of sessions on outcome in patients was evaluated. Results: Forty-nine patients (84.5% were completely cured. Age, sex, etiology, and duration did not significantly affect the treatment outcome. Unilateral BPPV can be treated significantly better than bilateral BPPV. Forty-seven patients who were completely treated needed 1 session and thirty-seven of them required 2 maneuvers. Conclusion: CRM is significantly effective for BPPV treatment. Treating unilateral BPPV is expected to be easier. As most of the patients will be cured by 1 or 2 maneuvers or in 1 session, patients who required more sessions or more maneuvers may not be completely treated.

  20. Effects of hamstring stretching on passive muscle stiffness vary between hip flexion and knee extension maneuvers.

    Science.gov (United States)

    Miyamoto, N; Hirata, K; Kanehisa, H

    2017-01-01

    The purpose of this study was to examine whether the effects of hamstring stretching on the passive stiffness of each of the long head of the biceps femoris (BFl), semitendinosus (ST), and semimembranosus (SM) vary between passive knee extension and hip flexion stretching maneuvers. In 12 male subjects, before and after five sets of 90 s static stretching, passive lengthening measurements where knee or hip joint was passively rotated to the maximal range of motion (ROM) were performed. During the passive lengthening, shear modulus of each muscle was measured by ultrasound shear wave elastography. Both stretching maneuvers significantly increased maximal ROM and decreased passive torque at a given joint angle. Passive knee extension stretching maneuver significantly reduced shear modulus at a given knee joint angle in all of BFl, ST, and SM. In contrast, the stretching effect by passive hip flexion maneuver was significant only in ST and SM. The present findings indicate that the effects of hamstring stretching on individual passive muscles' stiffness vary between passive knee extension and hip flexion stretching maneuvers. In terms of reducing the muscle stiffness of BFl, stretching of the hamstring should be performed by passive knee extension rather than hip flexion.

  1. THE EFFECTIVENESS OF SEMONT LIBERATORY MANEUVER IN ACUTE BENINGN PAROXYSMAL POSITIONAL VERTIGO PATIENTS

    Directory of Open Access Journals (Sweden)

    Achyutha Kiran Kumar

    2014-08-01

    Full Text Available Background: People with vestibular dysfunction complain of problems with balance and dizziness which creates a negative impact on the people and affects their quality of life. Medications help in the control of symptoms. There has been an increase in the implementation of many protocols for the rehabilitation of vestibular patients with follow up exercises for the treatment of BPPV. Methods: Thirty BPPV patients were identified by doing Dix- Hall pike positioning and their DHI scores were recorded. All patients were exclusively treated with Semont Liberatory maneuver. The effectiveness of the treatment was documented at 1 week and 1 month. Repeated procedures were performed if necessary. Results: After the treatment session of Semont Liberatory maneuver, the symptoms disappeared in 20 patients and have negative DHI test by 1st week, and of patients have negative DHI test by 1 month. The first success rate was 78% and the total success rate was 89%. Semont Liberatory maneuver also showed decrease in score of DHI [post-test] in 1 month duration. The patient who visited within one week after the onset of symptoms had good prognosis with Semont Liberatory maneuver. This protocol was ineffective in 4 patients. Conclusion: The Semont Liberatory maneuver is a safe and effective technique for treating BPPV patients.

  2. Quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo

    Institute of Scientific and Technical Information of China (English)

    Jinrang Li; Pengfei Guo; Shiyu Tian; Keliang Li; Hao Zhang

    2015-01-01

    Objective:To investigate the efficacy of quick repositioning maneuver for horizontal semicircular canal benign paroxysmal positional vertigo (H-BPPV). Methods:Clinical data of 67 patients with H-BPPV who underwent quick repositioning maneuver in our hospital from July 2009 to November 2014 were retrospectively analyzed. The maneuver involved rotating the patient in the axial plane for 180? from the involved side towards contralateral side as quickly as possible. Results:Complete symptom resolution was achieved in 61 patients (91.0%) at one week and in 64 patients (95.5%) at 3 months post-treatment. During the repositioning maneuver process, there were no obvious untoward responses except transient nausea with or without vomiting in a few patients. Conclusion:The results indicate that the quick repositioning maneuver is an easy and effective alternative treatment in the management of H-BPPV. Copyright © 2015 The Authors. Production & hosting by Elsevier (Singapore) Pte Ltd On behalf of PLA General Hospital Department of Otolaryngology Head and Neck Surgery. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

  3. Implementation of an Autonomous Multi-Maneuver Targeting Sequence for Lunar Trans-Earth Injection

    Science.gov (United States)

    Whitley, Ryan J.; Williams, Jacob

    2010-01-01

    Using a fully analytic initial guess estimate as a first iterate, a targeting procedure that constructs a flyable burn maneuver sequence to transfer a spacecraft from any closed Moon orbit to a desired Earth entry state is developed and implemented. The algorithm is built to support the need for an anytime abort capability for Orion. Based on project requirements, the Orion spacecraft must be able to autonomously calculate the translational maneuver targets for an entire Lunar mission. Translational maneuver target sequences for the Orion spacecraft include Lunar Orbit Insertion (LOI), Trans-Earth Injection (TEI), and Trajectory Correction Maneuvers (TCMs). This onboard capability is generally assumed to be supplemental to redundant ground computation in nominal mission operations and considered as a viable alternative primarily in loss of communications contingencies. Of these maneuvers, the ability to accurately and consistently establish a flyable 3-burn TEI target sequence is especially critical. The TEI is the sole means by which the crew can successfully return from the Moon to a narrowly banded Earth Entry Interface (EI) state. This is made even more critical by the desire for global access on the lunar surface. Currently, the designed propellant load is based on fully optimized TEI solutions for the worst case geometries associated with the accepted range of epochs and landing sites. This presents two challenges for an autonomous algorithm: in addition to being feasible, the targets must include burn sequences that do not exceed the anticipated propellant load.

  4. The influence of airway supporting maneuvers on glottis view in pediatric fiberoptic bronchoscopy

    Directory of Open Access Journals (Sweden)

    Tarik Umutoglu

    2015-10-01

    Full Text Available ABSTRACTINTRODUCTION:Flexible fiber optic bronchoscopy is a valuable intervention for evaluation and management of respiratory diseases in both infants, pediatric and adult patients. The aim of this study is to investigate the influence of the airway supporting maneuvers on glottis view during pediatric flexible fiberoptic bronchoscopy.MATERIALS AND METHODS:In this randomized, controlled, crossover study; patients aged between 0 and 15 years who underwent flexible fiberoptic bronchoscopy procedure having American Society of Anesthesiologists I---II risk score were included. Patients having risk of difficult intubation, intubated or patients with tracheostomy, and patients with reduced neck mobility or having cautions for neck mobility were excluded from this study. After obtaining best glottic view at the neutral position, patients were positioned jaw trust with open mouth, jaw trust with teeth prottution, head tilt chin lift and triple airway maneuvers and best glottis scores were recorded.RESULTS:Total of 121 pediatric patients, 57 girls and 64 boys, were included in this study. Both jaw trust with open mouth and jaw trust with teeth prottution maneuvers improved the glottis view compared with neutral position (p 0.05. Head tilt chin lift and triple airway maneuvers improved glottis view when compared with both jaw trust with open mouth and jaw trust with teeth prottution maneuvers and neutral position (p 0.05.

  5. Ship operation and failure mode analysis using a maneuver simulator

    Science.gov (United States)

    Cabrerizo-Morales, Miguel Angel; Molina, Rafael; de los Santos, Francisco; Camarero, Alberto

    2013-04-01

    In a ship or floating structure operation the agents that contribute to the systems behaviour are not only those derived from fluid-structure interaction, but also the ones linked to mooring-control line set-up evolution and human interaction. Therefore, the analysis of such systems is affected by boundary conditions that change during a complete operation. Frequently, monitoring techniques in laboratory (model) and field (prototype) are based in different instrumental techniques adding difficulty to data comparison and, in some cases, inducing precision and repeatability errors. For this reason, the main aim of this study is to develop the methods and tools to achieve a deep knowledge of those floating systems and obtain capabilities to optimize their operationally thresholds. This abstract presents a methodology and an instrumental system applicable both in field and laboratory: SRECMOCOS Project (Small scale REal-time Caisson MOnitoring and COntrol System). SRECMOCOS compiles three modules. For the monitoring and control of the structure it has been developed a synchronized open and modular microcontroller-based electronic system that comprises sensors, to monitor agents and reactions, and actuators to perform pertinent actions after processing the sensors' data. A secondary objective has been to design and implement a global scaled simulator (1:22), at the 3D basin of The Harbour Research Lab at Technical University of Madrid, in which climatic agents and those derived from the rig/maneuvering setup and the structural design were included. The particular case of Campamento's drydock, in Algeciras Bay (Spain), has been used to apply and validate the methodology. SRECMOCOS Project conjugates control, monitoring and wireless communication systems in a real time basis, offering the possibility to register and simulate all the parameters involved in port operations. This approach offers a step forward into a monitoring strategy to be included in monitoring

  6. Chaotic attitude and reorientation maneuver for completely liquid-filled spacecraft with flexible appendage

    Institute of Scientific and Technical Information of China (English)

    Baozeng Yue

    2009-01-01

    The present paper investigates the chaotic attitude dynamics and reorientation maneuver for completely viscous liquid-filled spacecraft with flexible appendage. All of the equations of motion are derived by using Lagrangian mechanics and then transformed into a form consisting of an unperturbed part plus perturbed terms so that the system's nonlinear characteristics can be exploited in phase space.Emphases are laid on the chaotic attitude dynamics produced from certain sets of physical parameter values of the spacecraft when energy dissipation acts to derive the body from minor to major axis spin. Numerical solutions of these equations show that the attitude dynamics of liquid-filled flexible spacecraft possesses characteristics common to random, nonperiodic solutions and chaos, and it is demonstrated that the desired reorientation maneuver is guaranteed by using a pair of thruster impulses. The control strategy for reorientation maneuver is designed and the numerical simulation results are presented for both the uncontrolled and controlled spins transition.

  7. Adaptive variable structure control based on backstepping for spacecraft with reaction wheels during attitude maneuver

    Institute of Scientific and Technical Information of China (English)

    SONG Bin; MA Guang-fu; LI Chuan-jiang

    2009-01-01

    An adaptive variable structure control method based on backstepping is proposed for the attitude maneuver problem of rigid spacecraft with reaction wheel dynamics in the presence of uncertain inertia matrix and external disturbances. The proposed control approach is a combination of the backstepping and the adaptive variable structure control. The cascaded structure of the attitude maneuver control system with reaction wheel dynamics gives the advantage for applying the backstepping method to construct Lyapunov functions. The robust stability to external disturbances and parametric uncertainty is guaranteed by the adaptive variable structure control. To validate the proposed control algorithm, numerical simulations using the proposed approach are performed for the attitude maneuver mission of rigid spacecraft with a configuration consisting of four reaction wheels for actuator and three magnetorquers for momentum unloading. Simulation results verify the effectiveness of the proposed control algorithm.

  8. Therapeutic effect of Epley maneuver on patients with posterior semicircular canal in benign paroxysmal positional vertigo

    Directory of Open Access Journals (Sweden)

    Gholamali Dashti-Khadivaki

    2010-06-01

    Full Text Available Background: Benign paroxysmal positional vertigo (BPPV is characterized by brief attacks of vertigo, nausea and/or positional nystagmus during head movements. Epley maneuver is one of the therapeutic processes for these patients and had various results in different studies. The objective of this study was to determine the efficacy of this procedure on treatment of patients with BPPV.Material and Methods: This study was performed from January 2008 till September 2009 in otolaryngology clinic of Khatam teaching hospital in Zahedan. The study was conducted among 67 patients (38 female, 29 male with p-BPPV between the ages of 27 and 68 years old. Epley maneuver with restriction was performed for treatment after diagnosis of BPPV and one week later, results evaluated using the Dix-Hallpike test.Result: 92.5% of patients had positive response to this type of treatment. Conclusions: The study revealed good efficacy of Epley maneuver on patients with BPPV

  9. Associating Crash Avoidance Maneuvers with Driver Attributes and Accident Characteristics: A Mixed Logit Model Approach

    DEFF Research Database (Denmark)

    Kaplan, Sigal; Prato, Carlo Giacomo

    2012-01-01

    This study focuses on the propensity of drivers to engage in crash avoidance maneuvers in relation to driver attributes, critical events, crash characteristics, vehicles involved, road characteristics and environmental attributes. Five alternative actions involving emergency lateral and speed...... as from the key role of the ability of drivers to perform effective corrective maneuvers for the success of automated in-vehicle warning and driver assistance systems. The analysis is conducted by means of a mixed logit model that accommodates correlations across alternatives and heteroscedasticity. Data...... for the analysis are retrieved from the General Estimates System (GES) crash database for the year 2009. Results show that (i) the nature of the critical event that made the crash imminent influences the choice of crash avoidance maneuvers, (ii) women and elderly have a lower propensity to conduct crash avoidance...

  10. Parallel Processing Based on Ship Maneuvering in Identification of Interaction Force Coefficients

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-jian; HUANG Guo-liang; DENG De-heng

    2008-01-01

    The parallel processing based on the free running model test was adopted to predict the interac-tion force coefficients (flow straightening coefficient and wake fraction) of ship maneuvering. And the multi-population genetic algorithm (MPGA) based on real coding that can contemporarily process the data of freerunning model and simulation of ship maneuvering was applied to solve the problem. Accordingly the optimalindividual was obtained using the method of genetic algorithm. The parallel processing of multi-populationsolved the prematurity in the identification for single population, meanwhile, the parallel processing of the dataof ship maneuvering (turning motion and zigzag motion) is an attempt to solve the coefficient drift problem.In order to validate the method, the interaction force coefficients were verified by the procedure and thesecoefficients measured were compared with those ones identified. The maximum error is less than 5%, and theidentification is an effective method.

  11. CLINICAL DIAGNOSIS OF SUBSCAPULARIS TENDON TEAR USING THE BEAR HUG SEMIOLOGICAL MANEUVER

    Science.gov (United States)

    Schiefer, Márcio; Júnior, Yonder Archanjo Ching-San; Silva, Sérgio Maurício; Fontenelle, César; Dias Carvalho, Marcos Genúncio; de Faria, Fabio Garcia; Franco, José Sérgio

    2015-01-01

    Objective: To evaluate the Bear Hug maneuver for clinically diagnosing subscapularis tendon tears, and compare this with other maneuvers described previously (Lift-off, Napoleon and Belly Press). Methods: Forty-nine patients with rotator cuff injuries who had undergone arthroscopy to repair the injury and had previously been assessed using the semiological maneuvers mentioned above were evaluated. Results: The diagnostic values obtained for the Bear Hug test were as follows: sensitivity 75%, specificity 56%, positive predictive value 62%, negative predictive value 70% and accuracy 65%. Conclusion: The highest sensitivity and negative predictive value values were obtained with the Bear Hug test. The highest specificity value was seen with the Lift-off test. The Belly press test gave the greatest specificity, positive predictive and accuracy values. PMID:27047870

  12. Attitude maneuver of spacecraft with a variable-speed double-gimbal control moment gyro

    Science.gov (United States)

    Jikuya, Ichiro; Fujii, Kenta; Yamada, Katsuhiko

    2016-10-01

    In this paper, two types of computational procedures are presented for a rest-to-rest spacecraft maneuver using a variable-speed double-gimbal control moment gyro (VSDGCMG). The first procedure is a numerical computational procedure in which a quasi-time-optimal trajectory satisfying several physical constraints is obtained by repeating the Newton's method. The other procedure is an approximate computational procedure in which an analytical solution is obtained by approximately solving a series of linear optimal control problems. The two procedures play complementary roles: the former is suitable for implementation, and the latter can be used to select an initial value for use in the former. The effectiveness of the proposed procedures is demonstrated by plotting the surfaces of maneuvering time for all rotational axes and by plotting time responses for several maneuvering examples.

  13. The Maneuver Planning Process for the Microwave Anisotropy Probe (MAP) Mission

    Science.gov (United States)

    Mesarch, Michael A.; Andrews, Stephen F.; Bauer, Frank (Technical Monitor)

    2002-01-01

    The Microwave Anisotropy Probe (MAP) mission utilized a strategy combining highly eccentric phasing loops with a lunar gravity assist to provide a zero-cost insertion into a Lissajous orbit about the Sun-Earth/Moon L2 point. 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. This paper will also describe how commercial off-the-shelf (COTS) tools were used to execute these tasks and produce a command sequence ready for upload to the spacecraft. These COTS tools included Satellite Tool Kit, MATLAB, and Matrix-X.

  14. Assessment Of The Aerodynamic And Aerothermodynamic Performance Of The USV-3 High-Lift Re-Entry Vehicle

    Science.gov (United States)

    Pezzella, Giuseppe; Richiello, Camillo; Russo, Gennaro

    2011-05-01

    This paper deals with the aerodynamic and aerothermodynamic trade-off analysis carried out with the aim to design a hypersonic flying test bed (FTB), namely USV3. Such vehicle will have to be launched with a small expendable launcher and shall re-enter the Earth atmosphere allowing to perform several experiments on critical re-entry phenomena. The demonstrator under study is a re-entry space glider characterized by a relatively simple vehicle architecture able to validate hypersonic aerothermodynamic design database and passenger experiments, including thermal shield and hot structures. Then, a summary review of the aerodynamic characteristics of two FTB concepts, compliant with a phase-A design level, has been provided hereinafter. Indeed, several design results, based both on engineering approach and computational fluid dynamics, are reported and discussed in the paper.

  15. Neutrinoless double beta decay

    Indian Academy of Sciences (India)

    Kai Zuber

    2012-10-01

    The physics potential of neutrinoless double beta decay is discussed. Furthermore, experimental considerations as well as the current status of experiments are presented. Finally, an outlook towards the future, work on nuclear matrix elements and alternative processes is given.

  16. ADAPTIVE PRACTICAL OUTPUT MANEUVERING CONTROL FOR A CLASS OF NONLINEAR SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Chunling WEI; Yuqiang WU; Shumin FEI

    2007-01-01

    This paper deals with the adaptive practical output maneuvering control problems for a class of nonlinear systems with uncontrollable unstable linearization.The objective is to design a smooth adaptive maneuvering controller to solve the geometric and dynamic tasks with an arbitrary small steady tracking error.The method of adding a power integrator and the robust recursive design technique are employed to force the system output to track a desired path and make the tracking speed to follow a desired speed along the path.An example is considered and simulation results are given.The proposed design procedure can be illustrated by the use of this example.

  17. Operationally optimal maneuver strategy for spacecraft injected into sub-geosynchronous transfer orbit

    Science.gov (United States)

    Kiran, B. S.; Singh, Satyendra; Negi, Kuldeep

    The GSAT-12 spacecraft is providing Communication services from the INSAT/GSAT system in the Indian region. The spacecraft carries 12 extended C-band transponders. GSAT-12 was launched by ISRO’s PSLV from Sriharikota, into a sub-geosynchronous Transfer Orbit (sub-GTO) of 284 x 21000 km with inclination 18 deg. This Mission successfully accomplished combined optimization of launch vehicle and satellite capabilities to maximize operational life of the s/c. This paper describes mission analysis carried out for GSAT-12 comprising launch window, orbital events study and orbit raising maneuver strategies considering various Mission operational constraints. GSAT-12 is equipped with two earth sensors (ES), three gyroscopes and digital sun sensor. The launch window was generated considering mission requirement of minimum 45 minutes of ES data for calibration of gyros with Roll-sun-pointing orientation in T.O. Since the T.O. period was a rather short 6.1 hr, required pitch biases were worked out to meet the gyro-calibration requirement. A 440 N Liquid Apogee Motor (LAM) is used for orbit raising. The objective of the maneuver strategy is to achieve desired drift orbit satisfying mission constraints and minimizing propellant expenditure. In case of sub-GTO, the optimal strategy is to first perform an in-plane maneuver at perigee to raise the apogee to synchronous level and then perform combined maneuvers at the synchronous apogee to achieve desired drift orbit. The perigee burn opportunities were examined considering ground station visibility requirement for monitoring the burn. Two maneuver strategies were proposed: an optimal five-burn strategy with two perigee burns centered around perigee#5 and perigee#8 with partial ground station visibility and three apogee burns with dual station visibility, a near-optimal five-burn strategy with two off-perigee burns at perigee#5 and perigee#8 with single ground station visibility and three apogee burns with dual station visibility

  18. A Study of Maneuvering Control for an Air Cushion Vehicle Based on Back Propagation Neural Network

    Institute of Scientific and Technical Information of China (English)

    LU Jun; HUANG Guo-liang; LI Shu-zhi

    2009-01-01

    A back propagation (BP) neural network mathematical model was established to investigate the maneuvering control of an air cushion vehicle (ACV). The calculation was based on four-freedom-degree model experiments of hydrodynamics and aerodynamics. It is necessary for the ACV to control the velocity and the yaw rate as well as the velocity angle at the same time. The yaw rate and the velocity angle must be controlled correspondingly because of the whipping, which is a special characteristic for the ACV. The calculation results show that it is an efficient way for the ACV's maneuvering control by using a BP neural network to adjust PID parameters online.

  19. Alpha and Beta Determinations

    CERN Document Server

    Dunietz, Isard

    1999-01-01

    Because the Bd -> J/psi Ks asymmetry determines only sin(2 beta), a discrete ambiguity in the true value of beta remains. This note reviews how the ambiguity can be removed. Extractions of the CKM angle alpha are discussed next. Some of the methods require very large data samples and will not be feasible in the near future. In the near future, semi-inclusive CP-violating searches could be undertaken, which are reviewed last.

  20. An evaluation of a resorbable (semirigid) GTR membrane in human periodontal intraosseous defects: A clinicoradiological re-entry study

    OpenAIRE

    Vinayak S Gowda; Vijay Chava; Ajeya E. G. Kumara

    2011-01-01

    Aim: To evaluate the effectiveness of a resorbable, semi rigid guided tissue regeneration (GTR) membrane in the treatment of periodontal intraosseous defects. Settings and Design: Randomized controlled clinicoradiological re-entry study. Materials and Methods: Eight patients with bilateral, identical intraosseous defects were selected. The sides for test and control group were randomly allocated to treat either with bioresorbable semi rigid membrane (test group) or open flap debridement (cont...

  1. FLPP IXV Re-entry Vehicle, Transonic Characterisation Based on FOI T1500 Wind Tunnel Tests and CFD

    Science.gov (United States)

    Torngren, L.; Chiarelli, C.; Mareschi, V.; Tribot, J.-P.; Binetti, P.; Walloschek, T.

    2009-01-01

    The European Space Agency ESA, has engaged in 2004, the IXV project (Intermediate eXperimental Vehicle) which is part of the FLPP (Future Launcher Preparatory Programme) aiming at answering to critical technological issues, while supporting the future generation launchers and to improve in general European capabilities in the strategic field of atmospheric re-entry for space transportation, exploration and scientific applications. The IXV key mission and system objectives are the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled re-entry system, integrating the critical re-entry technologies at the system level. The current IXV vehicle is a slender body type exhibiting rounded shape, thick body controlled by means of two control surfaces. The current mission is to perform an atmospheric re- entry ended by a safe recovery in supersonic regime. A potential extension of the flight domain down to the transonic regime was proposed to be analyzed. The objectives were to study the capability of the IXV for flying autonomously enabling a recovery of the vehicle by means of a subsonic parachute based DRS. The vehicle designed for the hypersonic speeds integrating a large base with only two control surfaces located close to the plane of symmetry is definitively not tuned for transonic ones. CFD done by Thales Alenia Space and wind tunnel activities involving FOI T1500 facility contributed to built up an Aerodynamic Data Base (AEDB) to be used as inputs for flying qualities analysis and re-entry simulations. The paper presents the main objectives of the transonic activities with emphasis on CFD and WTT including a description of the different prediction tools and discussing the main outcomes of the current data comparisons.

  2. {beta} - amyloid imaging probes

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Jae Min [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2007-04-15

    Imaging distribution of {beta} - amyloid plaques in Alzheimer's disease is very important for early and accurate diagnosis. Early trial of the {beta} -amyloid plaques includes using radiolabeled peptides which can be only applied for peripheral {beta} - amyloid plaques due to limited penetration through the blood brain barrier (BBB). Congo red or Chrysamine G derivatives were labeled with Tc-99m for imaging {beta} - amyloid plaques of Alzheimer patient's brain without success due to problem with BBB penetration. Thioflavin T derivatives gave breakthrough for {beta} - amyloid imaging in vivo, and a benzothiazole derivative [C-11]6-OH-BTA-1 brought a great success. Many other benzothiazole, benzoxazole, benzofuran, imidazopyridine, and styrylbenzene derivatives have been labeled with F-18 and I-123 to improve the imaging quality. However, [C-11]6-OH-BTA-1 still remains as the best. However, short half-life of C-11 is a limitation of wide distribution of this agent. So, it is still required to develop an Tc-99m, F-18 or I-123 labeled agent for {beta} - amyloid imaging agent.

  3. Beta cell dynamics: beta cell replenishment, beta cell compensation and diabetes.

    Science.gov (United States)

    Cerf, Marlon E

    2013-10-01

    Type 2 diabetes, characterized by persistent hyperglycemia, arises mostly from beta cell dysfunction and insulin resistance and remains a highly complex metabolic disease due to various stages in its pathogenesis. Glucose homeostasis is primarily regulated by insulin secretion from the beta cells in response to prevailing glycemia. Beta cell populations are dynamic as they respond to fluctuating insulin demand. Beta cell replenishment and death primarily regulate beta cell populations. Beta cells, pancreatic cells, and extra-pancreatic cells represent the three tiers for replenishing beta cells. In rodents, beta cell self-replenishment appears to be the dominant source for new beta cells supported by pancreatic cells (non-beta islet cells, acinar cells, and duct cells) and extra-pancreatic cells (liver, neural, and stem/progenitor cells). In humans, beta cell neogenesis from non-beta cells appears to be the dominant source of beta cell replenishment as limited beta cell self-replenishment occurs particularly in adulthood. Metabolic states of increased insulin demand trigger increased insulin synthesis and secretion from beta cells. Beta cells, therefore, adapt to support their physiology. Maintaining physiological beta cell populations is a strategy for targeting metabolic states of persistently increased insulin demand as in diabetes.

  4. Pressure applied by the healthcare staff on a cricoids cartilage simulator during Sellick's maneuver in rapid sequence intubation

    NARCIS (Netherlands)

    J.A. Calvache (Jose Andrés); L.C.B. Sandoval (Luz); W.A. Vargas (William Andres)

    2013-01-01

    textabstractBackground: Sellick's maneuver or cricoid pressure is a strategy used to prevent bronchoaspiration during the rapid intubation sequence. Several studies have described that the force required for an adequate maneuver is of 2.5-3.5 kg. The purpose of this paper was to determine the force

  5. 78 FR 11555 - Special Conditions: Embraer S.A., Model EMB-550 Airplane; Design Roll Maneuver for Electronic...

    Science.gov (United States)

    2013-02-19

    ...; Design Roll Maneuver for Electronic Flight Controls AGENCY: Federal Aviation Administration (FAA), DOT... EMB-550 airplane. This airplane will have a novel or unusual design feature(s) associated with the design roll maneuver for electronic flight controls, specifically an electronic flight control...

  6. Simulation of re-entry in a piece of myocardial tissue: strong sensitivity to spatial and temporal conditions.

    Science.gov (United States)

    Wohlfart, B; Ohlén, G; Karlsson, L

    1996-07-01

    A simple model for the simulation of re-entrant excitation was created. The model consists of a matrix of 15x15 compartments, where each compartment has its own action potential that depends dynamically on four ion currents (INa, ICa, Ik and Ib) having time and voltage-dependent activation and inactivation kinetics. The compartments were combined with resistors to simulate electrotonic interaction. At short excitation intervals the action potential was shortened in duration, and at even shorter coupling intervals decremental propagation occurred. Re-entry around an obstacle could be elicited in response to a properly timed extra stimulus. A time dependent unidirectional block was made by making some of the action potentials longer in duration. An obstacle was not a necessary substrate for re-entry, but the timing of the extra stimulus was critical. In the presence of an obstacle, the induction of re-entry was critically dependent on the shape of the obstacle. The most important result of the simulations is that the system is highly sensitive to the initial spatial and temporal conditions. These sensitivities are generic features of dynamic systems that are described by non-linear differential equations and are typical for chaotic systems. The system studied shows features associated with deterministic chaos.

  7. 6-OHDA Induces Cycle Reentry and Apoetosis of PC12 Cells through Activation of ERK1/2 Signaling Pathway

    Institute of Scientific and Technical Information of China (English)

    Zhentao ZHANG; Tao WANG; Xuebing CAO; Shenggang SUN; Lan WANG

    2009-01-01

    This study investigated the effect and mechanism of cell cycle reentry induced by 6-hydrodopamine (6-OHDA) in PCI2 cells.By using neural differentiated PCI2 cells treated with 6-OHDA,the apoptosis model of dopaminergic neurons was established.Cell viability was measured by MTT.Cell apoptosis and the distribution of cell cycle were assessed by flow cytometry.Western blot was used to detect the activation of extracellular regulator kinasel/2 (ERK1/2) pathway and the phosphorylation of retinoblastoma protein (RB).Our results showed that after PC12 cells were treated wtih 6-OHDA,the viability of PC12 cells was declined in a concentration-dependent manner.Flow cytometry revealed that 6-OHDA could increase the apoptosis ratio of PC12 cells in a time-dependent manner.The percentage of cells in G0/G1 phase of cell cycle was decreased and that in S phase and G2/M phase increased.Simultaneously,ERK1/2 pathway was activated and phos- phorylated RB increased.It was concluded that 6-OHDA could induce cell cycle reentry of dopa-minergic neurons through the activation of ERK1/2 pathway and RB phosphorylation.The aberrant cell cycle reentry contributes to the apoptosis of dopaminergic neurons.

  8. Potential dermal exposure in greenhouses for manual sprayers: analysis of the mix/load, application and re-entry stages.

    Science.gov (United States)

    Ramos, Laura M; Querejeta, Giselle A; Flores, Andrea P; Hughes, Enrique A; Zalts, Anita; Montserrat, Javier M

    2010-09-01

    An evaluation of the Potential Dermal Exposure for the mix/load, application and re-entry stages, associated with procymidone and deltamethrin usage, was carried out for tomatoes grown in greenhouses of small production units in Argentina. Eight experiments were done with four different operators, under typical field conditions with a lever operated backpack sprayer. The methodology applied was based on the Whole Body Dosimetry technique, evaluating a set of different data for the mix and load, application and re-entry operations. These results indicated that the Potential Dermal Exposure of the application step was (38+/-17)mLh(-1) with the highest proportion on torso, head and arms. When the three stages were compared, re-entry was found to contribute least towards the total Potential Dermal Exposure; meanwhile in all cases, except one, the mix/load operation was the stage with highest exposure. The Margin of Safety for each different operation was also calculated and the proportion of pesticide drift from the greenhouse to the environment is presented. These results emphasize the importance of improving the personal protection measures in the mix and load stage, an operation that is not usually associated with high-risk in small production units.

  9. The characteristics of registered nurses whose licenses expire: why they leave nursing and implications for retention and re-entry.

    Science.gov (United States)

    Skillman, Susan M; Palazzo, Lorella; Hart, L Gary; Keepnews, David

    2010-01-01

    Little is known about RNs who drop their licenses and their potential re-entry into the nursing workforce. The results of this study provide insight into reasons nurses leave their careers and the barriers to re-entry, all important indicators of the current professional climate for nursing. While representing only one state, these findings suggest that RNs who allow their licenses to expire do so because they have reached retirement age or, among those who do not cite age as a factor, because many are unable or unwilling to work in the field. Inactive nurses who might otherwise appear to be likely candidates for re-entry into the profession may not be easily encouraged to practice nursing again without significant changes in their personal circumstances or the health care work environment. Effective ways to address current and pending RN workforce shortages include expanding RN education capacity to produce more RNs who can contribute to the workforce across the coming decades, and promote work environments in which RNs want to, and are able to, practice across a long nursing career.

  10. Potential Dermal Exposure in greenhouses for manual sprayers: Analysis of the mix/load, application and re-entry stages

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Laura M.; Querejeta, Giselle A.; Flores, Andrea P.; Hughes, Enrique A.; Zalts, Anita [Instituto de Ciencias, Universidad Nacional de General Sarmiento (UNGS), J. M. Gutierrez 1150, (B1613GSX) Los Polvorines, Prov. de Buenos Aires (Argentina); Montserrat, Javier M., E-mail: jmontser@ungs.edu.ar [Instituto de Ciencias, Universidad Nacional de General Sarmiento (UNGS), J. M. Gutierrez 1150, (B1613GSX) Los Polvorines, Prov. de Buenos Aires (Argentina); Instituto de Investigaciones en Ingenieria Genetica y Biologia Molecular (CONICET), Vuelta de Obligado 2490, 2o piso, Buenos Aires (Argentina)

    2010-09-01

    An evaluation of the Potential Dermal Exposure for the mix/load, application and re-entry stages, associated with procymidone and deltamethrin usage, was carried out for tomatoes grown in greenhouses of small production units in Argentina. Eight experiments were done with four different operators, under typical field conditions with a lever operated backpack sprayer. The methodology applied was based on the Whole Body Dosimetry technique, evaluating a set of different data for the mix and load, application and re-entry operations. These results indicated that the Potential Dermal Exposure of the application step was (38 {+-} 17) mL h{sup -1} with the highest proportion on torso, head and arms. When the three stages were compared, re-entry was found to contribute least towards the total Potential Dermal Exposure; meanwhile in all cases, except one, the mix/load operation was the stage with highest exposure. The Margin of Safety for each different operation was also calculated and the proportion of pesticide drift from the greenhouse to the environment is presented. These results emphasize the importance of improving the personal protection measures in the mix and load stage, an operation that is not usually associated with high-risk in small production units.

  11. Using Transcutaneous Laryngeal Ultrasonography (TLUSG) to Assess Post-thyroidectomy Patients' Vocal Cords: Which Maneuver Best Optimizes Visualization and Assessment Accuracy?

    Science.gov (United States)

    Wong, Kai-Pun; Woo, Jung-Woo; Li, Jason Yu-Yin; Lee, Kyu Eun; Youn, Yeo Kyu; Lang, Brian Hung-Hin

    2016-03-01

    To assess vocal cord (VC) movement with transcutaneous laryngeal ultrasound (TLUSG), three maneuvers, namely passive (quiet respiration), active (phonation), and Valsalva maneuvers have been described. It remains unclear which maneuver or using more maneuvers provides better visualization and assessment accuracy. We prospectively evaluated 342 post-thyroidectomy patients from two centers. They underwent TLUSG with direct laryngoscopic (DL) validation afterwards. During TLUSG, patients were instructed to perform all three maneuvers (passive, active, and Valsalva). VC visualization rate and accuracy between three maneuvers were compared. Visualization rate tended to be higher in Valsalva maneuver than that in other two maneuvers (92.1% vs. passive: 91.5%; active: 89.8%). While 19 patients had post-operative VC palsy, passive maneuver had lower test specificity than active (94.3 vs. 97.6%, p = 0.01) and Valsalva maneuvers (94.3 vs. 97.4%, p = 0.02). In assessable VCs, passive maneuver has a higher ability to differentiate between mobile VCs and VC palsy (Area under ROC curve--passive: 0.942, active: 0.863, Valsalva: 0.893). TLUSG with more maneuvers did not improve sensitivity or specificity. On applying TLUSG as a screening tool (i.e., only selected patient with "unassessable" VCs or VCP on TLUSG for DL), Valsalva maneuver (85.96%) saved more patients from DL than passive (81.87%) or active (84.81%) maneuver. Passive maneuver has a higher ability to differentiate VC palsy from normal. Using TLUSG as a screening tool, Valsalva was the preferred maneuver as it was more specific, had high visualization rate, and saved more patients from DL.

  12. Reentry trajectory rapid optimization for hypersonic vehicle satisfying waypoint and no-fly zone constraints

    Institute of Scientific and Technical Information of China (English)

    Lu Wang,Qinghua Xing,; Yifan Mao

    2015-01-01

    To rapidly generate a reentry trajectory for hyper-sonic vehicle satisfying waypoint and no-fly zone constraints, a novel optimization method, which combines the improved parti-cle swarm optimization (PSO) algorithm with the improved Gauss pseudospectral method (GPM), is proposed. The improved PSO algorithm is used to generate a good initial value in a short time, and the mission of the improved GPM is to find the final solution with a high precision. In the improved PSO algorithm, by control-ling the entropy of the swarm in each dimension, the typical PSO algorithm’s weakness of being easy to fal into a local optimum can be overcome. In the improved GPM, two kinds of breaks are introduced to divide the trajectory into multiple segments, and the distribution of the Legendre-Gauss (LG) nodes can be altered, so that al the constraints can be satisfied strictly. Thereby the advan-tages of both the intel igent optimization algorithm and the direct method are combined. Simulation results demonstrate that the proposed method is insensitive to initial values, and it has more rapid convergence and higher precision than traditional ones.

  13. Germinal center reentries of BCL2-overexpressing B cells drive follicular lymphoma progression

    Science.gov (United States)

    Sungalee, Stéphanie; Mamessier, Emilie; Morgado, Ester; Grégoire, Emilie; Brohawn, Philip Z.; Morehouse, Christopher A.; Jouve, Nathalie; Monvoisin, Céline; Menard, Cédric; Debroas, Guilhaume; Faroudi, Mustapha; Mechin, Violaine; Navarro, Jean-Marc; Drevet, Charlotte; Eberle, Franziska C.; Chasson, Lionel; Baudimont, Fannie; Mancini, Stéphane J.; Tellier, Julie; Picquenot, Jean-Michel; Kelly, Rachel; Vineis, Paolo; Ruminy, Philippe; Chetaille, Bruno; Jaffe, Elaine S.; Schiff, Claudine; Hardwigsen, Jean; Tice, David A.; Higgs, Brandon W.; Tarte, Karin; Nadel, Bertrand; Roulland, Sandrine

    2014-01-01

    It has recently been demonstrated that memory B cells can reenter and reengage germinal center (GC) reactions, opening the possibility that multi-hit lymphomagenesis gradually occurs throughout life during successive immunological challenges. Here, we investigated this scenario in follicular lymphoma (FL), an indolent GC-derived malignancy. We developed a mouse model that recapitulates the FL hallmark t(14;18) translocation, which results in constitutive activation of antiapoptotic protein B cell lymphoma 2 (BCL2) in a subset of B cells, and applied a combination of molecular and immunofluorescence approaches to track normal and t(14;18)+ memory B cells in human and BCL2-overexpressing B cells in murine lymphoid tissues. BCL2-overexpressing B cells required multiple GC transits before acquiring FL-associated developmental arrest and presenting as GC B cells with constitutive activation–induced cytidine deaminase (AID) mutator activity. Moreover, multiple reentries into the GC were necessary for the progression to advanced precursor stages of FL. Together, our results demonstrate that protracted subversion of immune dynamics contributes to early dissemination and progression of t(14;18)+ precursors and shapes the systemic presentation of FL patients. PMID:25384217

  14. Numerical study of hypersonic flows over reentry configurations with different chemical nonequilibrium models

    Science.gov (United States)

    Hao, Jiaao; Wang, Jingying; Lee, Chunhian

    2016-09-01

    Effects of two different 11-species chemical reaction models on hypersonic reentry flow simulations are numerically investigated. These two models were proposed by Gupta (1990) and Park (1990) [12,15], respectively. In this study, two typical configurations, the RAM-C II vehicle and FIRE II capsule, are selected as test cases, whose thermo-chemical nonequilibrium flowfields are computed by a multi-block finite volume code using a two-temperature model (a translational-rotational temperature and a vibrational-electron-electronic temperature). In the RAM-C II case, it is indicated that although electron number density distributions of the two reaction models appear in a similar trend, their values are distinctively different. Results of the Gupta's model show a better agreement with the electrostatic probe data, while those of the Park's model are more consistent with the reflectometers data. Both models give similar temperature distributions. In the FIRE II case, the two models yield significantly different distribution profiles of ions and electrons, whose differences could reach an order of magnitude. In addition, an abnormal nonequilibrium relaxation process in the shock layer is found in the FIRE II flowfield simulated by the Gupta's model, which proves to be a consequence of electron impact ionization reactions.

  15. Near-Ultraviolet and Visible Spectroscopy of HAYABUSA Spacecraft Re-entry

    CERN Document Server

    Abe, Shinsuke; Kakinami, Yoshihiro; Iiyama, Ohmi; Kurosaki, Hirohisa; Shoemaker, Michael A; Shiba, Yasuo; Ueda, Masayoshi; Suzuki, Masaharu

    2011-01-01

    HAYABUSA is the first spacecraft ever to land on and lift off from any celestial body other than the moon. The mission, which returned asteroid samples to the Earth while overcoming various technical hurdles, ended on June 13, 2010, with the planned atmospheric re-entry. In order to safely deliver the sample return capsule, the HAYABUSA spacecraft ended its 7-year journey in a brilliant "artificial fireball" over the Australian desert. Spectroscopic observation was carried out in the near-ultraviolet and visible wavelengths between 3000 and 7500 \\AA at 3 - 20 \\AA resolution. Approximately 100 atomic lines such as Fe I, Mg I, Na I, Al I, Cr I, Mn I, Ni I, Ti I, Li I, Zn I, O I, and N I were identified from the spacecraft. Exotic atoms such as Cu I, Mo I, Xe I and Hg I were also detected. A strong Li I line (6708 \\AA) at a height of ~55 km originated from the onboard Li-Ion batteries. The FeO molecule bands at a height of ~63 km were probably formed in the wake of the spacecraft. The effective excitation temper...

  16. Active disturbance rejection based trajectory linearization control for hypersonic reentry vehicle with bounded uncertainties.

    Science.gov (United States)

    Shao, Xingling; Wang, Honglun

    2015-01-01

    This paper investigates a novel compound control scheme combined with the advantages of trajectory linearization control (TLC) and alternative active disturbance rejection control (ADRC) for hypersonic reentry vehicle (HRV) attitude tracking system with bounded uncertainties. Firstly, in order to overcome actuator saturation problem, nonlinear tracking differentiator (TD) is applied in the attitude loop to achieve fewer control consumption. Then, linear extended state observers (LESO) are constructed to estimate the uncertainties acting on the LTV system in the attitude and angular rate loop. In addition, feedback linearization (FL) based controllers are designed using estimates of uncertainties generated by LESO in each loop, which enable the tracking error for closed-loop system in the presence of large uncertainties to converge to the residual set of the origin asymptotically. Finally, the compound controllers are derived by integrating with the nominal controller for open-loop nonlinear system and FL based controller. Also, comparisons and simulation results are presented to illustrate the effectiveness of the control strategy.

  17. Narrative change, narrative stability, and structural constraint: The case of prisoner reentry narratives.

    Science.gov (United States)

    Harding, David J; Dobson, Cheyney C; Wyse, Jessica J B; Morenoff, Jeffrey D

    2017-03-01

    Cultural sociologists and other social scientists have increasingly used the concept of narrative as a theoretical tool to understand how individuals make sense of the links between their past, present, and future, how individuals construct social identities from cultural building blocks, and how culture shapes social action and individual behavior. Despite its richness, we contend that the narratives literature has yet to grapple with narrative change and stability when structural constraints or barriers challenge personal narratives and narrative identities. Particularly for marginalized groups, the potential incompatibility of personal narratives with daily experiences raises questions about the capacity of narratives to influence behavior and decision-making. In this study we draw on prospective longitudinal data on the reentry narratives and narrative identities of former prisoners to understand how narratives do and not change when confronted with contradictory experiences and structural constraints. We identify and describe the processes generating narrative change and stability among our subjects. These findings inform a framework for studying narrative change and stability based on four factors: the content of the narrative itself, the structural circumstances experienced by the individual, the institutional contexts in which the individual is embedded, and the social networks in which the individual is embedded.

  18. Reusable Reentry Satellite (RRS) system design study. Phase B, appendix E: Attitude control system study

    Science.gov (United States)

    1991-01-01

    A study which consisted of a series of design analyses for an Attitude Control System (ACS) to be incorporated into the Re-usable Re-entry Satellite (RRS) was performed. The main thrust of the study was associated with defining the control laws and estimating the mass and power requirements of the ACS needed to meet the specified performance goals. The analyses concentrated on the different on-orbit control modes which start immediately after the separation of the RRS from the launch vehicle. The three distinct on-orbit modes considered for these analyses are as follows: (1) Mode 1 - A Gravity Gradient (GG) three-axis stabilized spacecraft with active magnetic control; (2) Mode 2 - A GG stabilized mode with a controlled yaw rotation rate ('rotisserie') using three-axis magnetic control and also incorporating a 10 N-m-s momentum wheel along the (Z) yaw axis; and (3) Mode 3 - A spin stabilized mode of operation with the spin about the pitch (Y) axis, incorporating a 20 N-m-s momentum wheel along the pitch (Y) axis and attitude control via thrusters. To investigate the capabilities of the different controllers in these various operational modes, a series of computer simulations and trade-off analyses have been made to evaluate the achievable performance levels, and the necessary mass and power requirements.

  19. A New Strategy of Guidance Command Generation for Re-entry Vehicle

    Directory of Open Access Journals (Sweden)

    Xie DaoCheng

    2013-01-01

    Full Text Available Guidance command for re-entry vehicle can be in various formats, but the Euler angles can be provided directly by gyros, so designers used to develop autopilot with commands of Euler angles. After the generation of commands of angle of attack and sideslip angle, it’s important to settle how to convert commands of angle of attack and sideslip angle to commands of Euler angles. Traditional conversion strategy relies on bank angle, but the solution to bank angle comprises complicated calculation and can’t be precise. This paper introduces a new conversion strategy of guidance command. This strategy relies on the relative position and velocity measured by seeker, an auxiliary coordinate is established as a transition, the transformation matrix from launch coordinate to body coordinate is solved in a new way, then the commands of Euler angles are obtained. The calculation of bank angle is avoided. The autopilot designed with the converted Euler-angle commands, can track commands of angle of attack and sideslip angle steadily. The vehicle reaches the target point precisely. Simulation results show that the new conversion strategy based on seeker information from commands of angle of attack and sideslip angle to Euler-angle commands is valid.

  20. A New Strategy of Guidance Command Generation for Re-entry Vehicle

    Directory of Open Access Journals (Sweden)

    Xie Daocheng

    2013-01-01

    Full Text Available Guidance command for re-entry vehicle can be in lots of formats, but the Euler angles can be provided directly by gyros, so designers used to develop autopilot with commands of Euler angles. After the generation of commands of attack angle and sideslip angle, it’s important to settle how to convert commands of attack angle and sideslip angle to commands of Euler angles. Traditional conversion strategy relies on bank angle, solution to bank angle comprises complicated calculation and can’t be precise. This paper introduces a new conversion strategy of guidance command. This strategy relies on the relative position and velocity measured by seeker, an auxiliary coordinateis established as a transition, the transformation matrix from launch coordinate to body coordinate is solved in a new way, then the commands of Euler angles are obtained. The calculation of bank angle is avoided. The autopilot designed with the converted Euler-angle commands, can track commands of attack angle and sideslip angle steadily.The vehicle reaches the target point precisely. Simulation results show that the new conversion strategy based on seeker information from commands of attack angle and sideslip angle to Euler-angle commands is right.Defence Science Journal, 2013, 63(1, pp.93-100, DOI:http://dx.doi.org/10.14429/dsj.63.2360

  1. Finite-Time Reentry Attitude Control Using Time-Varying Sliding Mode and Disturbance Observer

    Directory of Open Access Journals (Sweden)

    Xuzhong Wu

    2015-01-01

    Full Text Available This paper presents the finite-time attitude control problem for reentry vehicle with redundant actuators in consideration of planet uncertainties and external disturbances. Firstly, feedback linearization technique is used to cancel the nonlinearities of equations of motion to construct a basic mode for attitude controller. Secondly, two kinds of time-varying sliding mode control methods with disturbance observer are integrated with the basic mode in order to enhance the control performance and system robustness. One method is designed based on boundary layer technique and the other is a novel second-order sliding model control method. The finite-time stability analyses of both resultant closed-loop systems are carried out. Furthermore, after attitude controller produces the torque commands, an optimization control allocation approach is introduced to allocate them into aerodynamic surface deflections and on-off reaction control system thrusts. Finally, the numerical simulation results demonstrate that both of the time-varying sliding mode control methods are robust to uncertainties and disturbances without chattering phenomenon. Moreover, the proposed second-order sliding mode control method possesses better control accuracy.

  2. An optimal fuzzy PID control approach for docking maneuver of two spacecraft: Orientational motion

    Directory of Open Access Journals (Sweden)

    A. Kosari

    2017-02-01

    Full Text Available This paper describes a scheme for a Fuzzy-Proportional Integral Derivative (FPID controller based on genetic algorithm (GA, in a docking maneuver of two spacecraft. The docking maneuver consists of two parts: translation and orientation. Euler’s gyroscopic equation is applied to obtain governing equations of orientational phase. Here, a designed fuzzy-PID controller for stabilization purpose of orientational phase of a docking maneuver is presented based on the Single Input Fuzzy Inference Motor (SIFIMs dynamically connected Preferrer Fuzzy Inference Motor (PFIM. This fuzzy-PID controller takes the error signal of Euler’s angles and the error of angular velocities of the chaser as its input items, and the driving force as its output. The parameters of the controller are ascertained by using a genetic algorithm. Conflicting objective functions (which their 3D pareto frontiers are obtained by Multi-objective Genetic Algorithm (MOGA are distance errors from the set point, angle errors from the set point, and control efforts. Optimization constraint is maximal of the momentum produced by momentum wheels. The result of optimum point demonstrates that the designed controller makes an efficient performance in the orientational phase of the chaser spacecraft. Compared to similar works, some of system parameters like settling time are improved and overshoot (as a critical parameter in docking maneuver is decreased.

  3. Four-Impulsive Rendezvous Maneuvers for Spacecrafts in Circular Orbits Using Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Denilson Paulo Souza dos Santos

    2012-01-01

    Full Text Available Spacecraft maneuvers is a very important topic in aerospace engineering activities today. In a more generic way, a spacecraft maneuver has the objective of transferring a spacecraft from one orbit to another, taking into account some restrictions. In the present paper, the problem of rendezvous is considered. In this type of problem, it is necessary to transfer a spacecraft from one orbit to another, but with the extra constraint of meeting another spacecraft when reaching the final orbit. In particular, the present paper aims to analyze rendezvous maneuvers between two coplanar circular orbits, seeking to perform this transfer with lowest possible fuel consumption, assuming that this problem is time-free and using four burns during the process. The assumption of four burns is used to represent a constraint posed by a real mission. Then, a genetic algorithm is used to solve the problem. After that, a study is made for a maneuver that will make a spacecraft to encounter a planet, in order to make a close approach that will change its energy. Several simulations are presented.

  4. The Relationship between Submental Surface Electromyography and Hyo-Laryngeal Kinematic Measures of Mendelsohn Maneuver Duration

    Science.gov (United States)

    Azola, Alba M.; Greene, Lindsey R.; Taylor-Kamara, Isha; Macrae, Phoebe; Anderson, Cheryl; Humbert, Ianessa A.

    2015-01-01

    Purpose: The Mendelsohn Maneuver (MM) is a commonly prescribed technique that is taught to individuals with dysphagia to improve swallowing ability. Due to cost and safety concerns associated with videofluoroscopy (VFS) use, submental surface electromyography (ssEMG) is commonly used in place of VFS to train the MM in clinical and research…

  5. Multislice spiral computed tomography to determine the effects of a recruitment maneuver in experimental lung injury

    Energy Technology Data Exchange (ETDEWEB)

    Henzler, Dietrich; Rossaint, Rolf [University Hospital, RWTH Aachen, Anesthesiology Department, Aachen (Germany); Mahnken, Andreas H.; Wildberger, Joachim E.; Guenther, Rolf W. [University Hospital of the RWTH Aachen, Clinic of Diagnostic Radiology, Aachen (Germany); Kuhlen, Ralf [University Hospital of the RWTH Aachen, Operative Intensive Care Department, Aachen (Germany)

    2006-06-15

    Although recruitment of atelectatic lung is a common aim in acute respiratory distress syndrome (ARDS), the effects of a recruitment maneuver have not been assessed quantitatively. By multislice spiral CT (MSCT), we analyzed the changes in lung volumes calculated from the changes in the CT values of hyperinflated (V{sub HYP}), normally (V{sub NORM}), poorly (V{sub POOR}) and nonaerated (V{sub NON}) lung in eight mechanically ventilated pigs with saline lavage-induced acute lung injury before and after a recruitment maneuver. This was compared to single slice analysis near the diaphragm. The increase in aerated lung was mainly for V{sub POOR} and the less in V{sub NORM}. Total lung volume and intrathoracic gas increased. No differences were found for tidal volumes measured by spirometry or determined by CT. The inspiratory-expiratory volume differences were not different after the recruitment maneuver in V{sub NON} (from 62{+-}18 ml to 43{+-}26 ml, P=0.114), and in V{sub NORM} (from 216{+-}51 ml to 251{+-}37 ml, P=0.102). Single slice analysis significantly underestimated the increase in normally and poorly aerated lung. Quantitative analysis of lung volumes by whole lung MSCT revealed the increase of poorly aerated lung as the main mechanism of a standard recruitment maneuver. MSCT can provide additional information as compared to single slice CT. (orig.)

  6. Vertigo during the Epley maneuver and success rate in patients with BPPV.

    Science.gov (United States)

    Fyrmpas, Georgios; Barkoulas, Eustathios; Haidich, Anna Bettina; Tsalighopoulos, Miltiadis

    2013-09-01

    To investigate whether reported vertigo during the Epley maneuver predicts therapeutic success in patients with benign paroxysmal positioning vertigo of the posterior semicircular canal (pc-BPPV). Fifty consecutive adult patients with pc-BPPV, based on a positive Dix-Hallpike test (DHT), were treated with the Epley maneuver and retested after 2 days. Patients were asked to report the presence of vertigo upon assuming each of the four positions of the maneuver. Thirty seven patients (74 %) were treated successfully in one session. Twenty out of 23 patients who reported vertigo at turning the head to the opposite side (2nd position) had a negative DHT on follow-up. These patients had a higher chance of a successful outcome compared to patients who did not report vertigo in the 2nd position (Odds ratio 5.3, 95 % CI: 1.3-22.2, p = 0.022). Report of vertigo at the other positions was not associated with the outcome. Report of vertigo at the second position of a single modified Epley maneuver is associated with therapeutic success.

  7. Acute effects of physiotherapeutic respiratory maneuvers in critically ill patients with craniocerebral trauma

    Directory of Open Access Journals (Sweden)

    Manoel Luiz de Cerqueira Neto

    2013-09-01

    Full Text Available OBJECTIVE: To evaluate the effects of physiotherapeutic respiratory maneuvers on cerebral and cardiovascular hemodynamics and blood gas variables. METHOD: A descriptive, longitudinal, prospective, nonrandomized clinical trial that included 20 critical patients with severe craniocerebral trauma who were receiving mechanical ventilation and who were admitted to the intensive care unit. Each patient was subjected to the physiotherapeutic maneuvers of vibrocompression and increased manual expiratory flow (5 minutes on each hemithorax, along with subsequent airway suctioning with prior instillation of saline solution, hyperinflation and hyperoxygenation. Variables related to cardiovascular and cerebral hemodynamics and blood gas variables were recorded after each vibrocompression, increased manual expiratory flow and airway suctioning maneuver and 10 minutes after the end of airway suctioning. RESULTS: The hemodynamic and blood gas variables were maintained during vibrocompression and increased manual expiratory flow maneuvers; however, there were increases in mean arterial pressure, intracranial pressure, heart rate, pulmonary arterial pressure and pulmonary capillary pressure during airway suctioning. All of the values returned to baseline 10 minutes after the end of airway suctioning. CONCLUSION: Respiratory physiotherapy can be safely performed on patients with severe craniocerebral trauma. Additional caution must be taken when performing airway suctioning because this technique alters cerebral and cardiovascular hemodynamics, even in sedated and paralyzed patients.

  8. Cooperative maneuvering in close environments among cybercars and dual-mode cars

    NARCIS (Netherlands)

    Milanés, V.; Alonso, J.; Bouraoui, L.; Ploeg, J.

    2011-01-01

    This paper describes the results of vehicle-to-vehicle (V2V) and infrastructure-to-vehicle (I2V) experiments implementing cooperative maneuvering for three different vehicles driving automatically. The cars used were cybercars from the Institut National de Recherche en Informatique et Automatique (I

  9. "Roller coaster maneuver via lateral orbital approach" for reduction of isolated zygomatic arch fractures.

    Science.gov (United States)

    Pilanci, Ozgur; Basaran, Karaca; Datli, Asli; Kuvat, Samet Vasfi

    2013-11-01

    Numerous techniques have been reported for the reduction of zygomatic arch fractures. In this article, we aimed to describe a technique we named as "roller coaster maneuver via lateral orbital approach" to closed reduction of the isolated-type zygomatic arch fractures. Surgical outcomes of 14 patients treated with this method were outlined.

  10. Evaluation of Discrimination Technologies and Classification Results Live Site Demonstration: Former Waikoloa Maneuver Area

    Science.gov (United States)

    2015-06-01

    investigated to ensure that all TOI were recovered. 15. SUBJECT TERMS MetalMapper, UX -Analyze, UXO, Former Waikoloa Maneuver Area, discrimination...26 5.7 Munitions Debris Management ................................................................................. 27 6.0...conditions. • Investigate in cooperation with regulators and program managers how classification technologies can be implemented in munitions and

  11. 46 CFR 35.20-40 - Maneuvering characteristics-T/OC.

    Science.gov (United States)

    2010-10-01

    ... for the normal load and normal ballast condition for: (1) Calm weather—wind 10 knots or less, calm sea... conditions, upon which the maneuvering information is based, are varied: (1) Calm weather—wind 10 knots or... calculations; (4) Simulations; (5) Information established from another vessel of similar hull form,...

  12. Linearity of electrical impedance tomography during maximum effort breathing and forced expiration maneuvers.

    Science.gov (United States)

    Ngo, Chuong; Leonhardt, Steffen; Zhang, Tony; Lüken, Markus; Misgeld, Berno; Vollmer, Thomas; Tenbrock, Klaus; Lehmann, Sylvia

    2017-01-01

    Electrical impedance tomography (EIT) provides global and regional information about ventilation by means of relative changes in electrical impedance measured with electrodes placed around the thorax. In combination with lung function tests, e.g. spirometry and body plethysmography, regional information about lung ventilation can be achieved. Impedance changes strictly correlate with lung volume during tidal breathing and mechanical ventilation. Initial studies presumed a correlation also during forced expiration maneuvers. To quantify the validity of this correlation in extreme lung volume changes during forced breathing, a measurement system was set up and applied on seven lung-healthy volunteers. Simultaneous measurements of changes in lung volume using EIT imaging and pneumotachography were obtained with different breathing patterns. Data was divided into a synchronizing phase (spontaneous breathing) and a test phase (maximum effort breathing and forced maneuvers). The EIT impedance changes correlate strictly with spirometric data during slow breathing with increasing and maximum effort ([Formula: see text]) and during forced expiration maneuvers ([Formula: see text]). Strong correlations in spirometric volume parameters [Formula: see text] ([Formula: see text]), [Formula: see text]/FVC ([Formula: see text]), and flow parameters PEF, [Formula: see text], [Formula: see text], [Formula: see text] ([Formula: see text]) were observed. According to the linearity during forced expiration maneuvers, EIT can be used during pulmonary function testing in combination with spirometry for visualisation of regional lung ventilation.

  13. The Heimlich maneuver. Best technique for saving any choking victim's life.

    Science.gov (United States)

    Heimlich, H J; Patrick, E A

    1990-05-01

    The American Red Cross (ARC) and the American Heart Association (AHA) advocated backslaps, chest thrusts, and abdominal thrusts for 10 years after the Heimlich maneuver was introduced in 1974. Even after the Surgeon General in 1985 declared these methods to be "hazardous, even lethal," the ARC and the AHA continue to recommend backslaps and chest thrusts for infants under 1 year of age. ARC and AHA instructional materials that advocate use of these methods have not been recalled, and the public has not been warned of the dangers. One cause of the confusion about backslaps is the flawed belief that gas pressure alone removes a foreign body. In addition, there is lack of understanding that, compared with the Heimlich maneuver, the backslap produces an insignificant amount of the energy required to expel an object from the airway. In fact, the energy produced by the backslap drives the foreign object in the wrong direction, toward the lungs, while the energy produced by the Heimlich maneuver drives the object away from the lungs, toward the mouth. Backslaps and chest thrusts should be publicly recalled as a treatment for choking infants before further deaths and injuries occur. The Heimlich maneuver is the best rescue technique for treating choking victims of all ages.

  14. Dynamics and control of flexible spacecraft during and after slewing maneuvers

    Science.gov (United States)

    Kakad, Yogendra P.

    1989-01-01

    The dynamics and control of slewing maneuvers of NASA Spacecraft COntrol Laboratory Experiment (SCOLE) are analyzed. The control problem of slewing maneuvers of SCOLE is formulated in terms of an arbitrary maneuver about any given axis. The control system is developed for the combined problem of rigid-body slew maneuver and vibration suppression of the flexible appendage. The control problem formulation incorporates the nonlinear dynamical equations derived previously, and is expressed in terms of a two-point boundary value problem utilizing a quadratic type of performance index. The two-point boundary value problem is solved as a hierarchical control problem with the overall system being split in terms of two subsystems, namely the slewing of the entire assembly and the vibration suppression of the flexible antenna. The coupling variables between the two dynamical subsystems are identified and these two subsystems for control purposes are treated independently in parallel at the first level. Then the state-space trajectory of the combined problem is optimized at the second level.

  15. Ground crewmen maneuver the Helios Prototype flying wing on its ground support dolly during function

    Science.gov (United States)

    2001-01-01

    Ground crewmen maneuver AeroVironment's solar-powered Helios Prototype flying wing on its ground support dolly during functional checkouts prior to its first flights under solar power from the U.S. Navy's Pacific Missile Range Facility on Kaua'i, Hawaii.

  16. Optimized routing on agricultural fields by minimizing maneuvering and servicing time

    NARCIS (Netherlands)

    Spekken, M.; Bruin, de S.

    2013-01-01

    Agricultural machines spend a significant part of their time on non-productive operations such as maneuvering near the boundaries of the field and loading or offloading of inputs or outputs (here referred to as servicing). This paper integrates existing methods for route optimization so as to minimi

  17. Effect of Driver Scope Awareness in the Lane Changing Maneuvers Using Cellular Automaton Model

    Directory of Open Access Journals (Sweden)

    Kohei Arai

    2013-07-01

    Full Text Available This paper investigated the effect of drivers’ visibility and their perception (e.g., to estimate the speed and arrival time of another vehicle on the lane changing maneuver. The term of scope awareness was used to describe the visibility required by the driver to make a perception about road condition and the speed of vehicle that exist in that road. A computer simulation model was conducted to show this driver awareness behavior. This studying attempt to precisely catching the lane changing behavior and illustrate the scope awareness parameter that reflects driver behavior. This paper proposes a simple cellular automata model for studying driver visibility effects of lane changing maneuver and driver perception of estimated speed. Different values of scope awareness were examined to capture its effect on the traffic flow. Simulation results show the ability of this model to capture the important features of lane changing maneuver and revealed the appearance of the short-thin solid line jam and the wide solid line jam in the traffic flow as the consequences of lane changing maneuver.

  18. Preparing GMAT for Operational Maneuver Planning of the Advanced Composition Explorer (ACE)

    Science.gov (United States)

    Qureshi, Rizwan Hamid; Hughes, Steven P.

    2014-01-01

    The General Mission Analysis Tool (GMAT) is an open-source space mission design, analysis and trajectory optimization tool. GMAT is developed by a team of NASA, private industry, public and private contributors. GMAT is designed to model, optimize and estimate spacecraft trajectories in flight regimes ranging from low Earth orbit to lunar applications, interplanetary trajectories and other deep space missions. GMAT has also been flight qualified to support operational maneuver planning for the Advanced Composition Explorer (ACE) mission. ACE was launched in August, 1997 and is orbiting the Sun-Earth L1 libration point. The primary science objective of ACE is to study the composition of both the solar wind and the galactic cosmic rays. Operational orbit determination, maneuver operations and product generation for ACE are conducted by NASA Goddard Space Flight Center (GSFC) Flight Dynamics Facility (FDF). This paper discusses the entire engineering lifecycle and major operational certification milestones that GMAT successfully completed to obtain operational certification for the ACE mission. Operational certification milestones such as gathering of the requirements for ACE operational maneuver planning, gap analysis, test plans and procedures development, system design, pre-shadow operations, training to FDF ACE maneuver planners, shadow operations, Test Readiness Review (TRR) and finally Operational Readiness Review (ORR) are discussed. These efforts have demonstrated that GMAT is flight quality software ready to support ACE mission operations in the FDF.

  19. The Mentorship Course of Action: Increasing African American Interest in the Maneuver Branches.

    Science.gov (United States)

    2011-06-10

    which provides the remaining 38 percent of new officers a year, falls under the command of the Infantry School at Fort Benning, Georgia (Wardinski, Lyle...Course to visit their alma maters and espouse the values of the maneuver branches and ―emphasize better communication skills training at

  20. An integrated approach for risk object re-entry predictions in terms of KS elements and genetic algorithm

    Science.gov (United States)

    Sharma, R. K.; Anil Kumar, A. K.; Xavier James Raj, M.

    The accurate estimation of the orbital lifetime of decaying near-Earth objects is of considerable importance for prediction of risk object re-entry time and proper planning of mitigation strategies and hazard assessment. It has become necessary to use extremely complex force models to match with the present operational requirements and observational techniques. The problem becomes all the more complicated in the near-Earth environment due to the fact that the object is influenced by the non-spherical effects of the Earth's gravitational field as well as the dissipative effects of the Earth's atmosphere. The database available for the re-entry time or orbital lifetime prediction of the debris objects is based on the set of Two Line Elements (TLEs) provided by the agencies like NORAD. These TLEs provide information regarding the orbital parameters together with rate of mean motion decay and an equivalent ballistic coefficient B*. The objects physical parameters like mass, area of cross section, shape and dimensions are not available accurately and the modelling of the atmosphere in which objects decay takes place is also uncertain. Besides, the tumbling effect of the body and gas molecular interaction, further makes the prediction of re-entry time a very complicated exercise. The method of the K-S total-energy element equations (Stiefel & Scheifele 1971) is a powerful method for numerical solution with respect to any type of perturbing forces, as the equations are less sensitive to round-off and truncation errors in the numerical algorithm. The equations are everywhere regular in contrast with the classical Newtonian equations, which are singular at the collision of the two bodies. The equations are smoothed for eccentric orbits because eccentric anomaly is the independent variable. Genetic Algorithms (Deb 1995) has received a great deal of attention regarding their potential as an optimisation technique for complex functions. This paper highlights the implementation

  1. Boosted beta regression.

    Directory of Open Access Journals (Sweden)

    Matthias Schmid

    Full Text Available Regression analysis with a bounded outcome is a common problem in applied statistics. Typical examples include regression models for percentage outcomes and the analysis of ratings that are measured on a bounded scale. In this paper, we consider beta regression, which is a generalization of logit models to situations where the response is continuous on the interval (0,1. Consequently, beta regression is a convenient tool for analyzing percentage responses. The classical approach to fit a beta regression model is to use maximum likelihood estimation with subsequent AIC-based variable selection. As an alternative to this established - yet unstable - approach, we propose a new estimation technique called boosted beta regression. With boosted beta regression estimation and variable selection can be carried out simultaneously in a highly efficient way. Additionally, both the mean and the variance of a percentage response can be modeled using flexible nonlinear covariate effects. As a consequence, the new method accounts for common problems such as overdispersion and non-binomial variance structures.

  2. Doppler ultrasonography measuement of hepatic hemodynamics during Valsalva maneuver: healthy volunteers study

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Dong Ho; Son, Young Jin; Lee, Young Hwan; Yoon, Kwon Ha [Dept. of Radiology, Wonkwang University School of Medicine, Iksan (Korea, Republic of)

    2015-01-15

    The aim of our study was to assess the hemodynamic change of liver during the Valsalva maneuver using Doppler ultrasonography. Thirty healthy men volunteers were enrolled (mean age, 25.5±3.64 years). The diameter, minimal and maximal velocities, and volume flow of intrahepatic inferior vena cava (IVC), middle hepatic vein (MHV), and right main portal vein (RMPV) was measured during both rest and Valsalva maneuver. These changes were compared using paired t-test. The mean diameters (cm) of the intrahepatic IVC at rest and Valsalva maneuver were 1.94±0.40 versus 0.56±0.66 (P<0.001). The mean diameter (cm), minimal velocity (cm/sec), maximal velocity (cm/sec), and volume flow (mL/min) of MHV at rest and Valsalva maneuver were 0.60±0.15 versus 0.38±0.20 (P<0.001), -7.98±5.47 versus 25.74±13.13 (P<0.001), 21.34±6.89 versus 35.12±19.95 (P=0.002), and 106.94±97.65 versus 153.90±151.80 (P=0.014), respectively. Those of RMPV at rest and Valsalva maneuver were 0.78±0.21 versus 0.76±0.20 (P=0.485), 20.21±8.22 versus 18.73±7.43 (P=0.351), 26.79±8.85 versus 24.93±9.91 (P=0.275), and 391.52±265.63 versus 378.43±239.36 (P=0.315), respectively. The blood flow velocity and volume flow of MHV increased significantly during Valsalva maneuver. These findings suggest that hepatic vein might play an important role to maintain venous return to the heart during the maneuver.

  3. The predictive value of Muller maneuver in REM-dependent obstructive sleep apnea.

    Science.gov (United States)

    Ozcan, Kursat Murat; Ozcan, Muge; Ozdogan, Fatih; Hizli, Omer; Dere, Huseyin; Unal, Adnan

    2013-09-01

    To our knowledge, no studies up to date have investigated the correlation of rapid eye movement (REM) dependent obstructive sleep apnea syndrome (OSAS) and Muller maneuver. The aim of this study is to investigate whether REM-dependent OSAS is predicted by the findings of the Muller maneuver. The study was conducted on 149 patients with witnessed apnea and daytime sleepiness. Muller maneuver was performed to all patients and the obstruction site was determined using a five-point scale. Then, polysomnography of the patient was obtained and the apnea-hypopnea indexes were determined in total sleep time, REM-dependent sleep and non-REM-dependent sleep. The correlations between the Muller maneuver findings and polysomnographic data were analyzed. The ages of the patients included in the study ranged between 25 and 73 years with a mean age of 49.3 ± 10.1 years. Their mean body mass index was 30.8 ± 5.1 kg/m(2) (range 21.9-55.4 kg/m(2)). The patients' mean apnea-hypopnea indexes in total sleep time was 28.1 and ranged between 5.4 and 124.3. REM-dependent OSAS was determined in 49 patients. When the data were analyzed, it was determined that there were no statistically significant correlations between tongue base or lateral pharyngeal band obstruction at the level of hypopharynx and the REM-dependent OSAS. At the level of the soft palate, the obstruction caused by the lateral pharyngeal bands or soft palate and REM dependency did not show any statistically significant correlation (p > 0.05). In conclusion, Muller maneuver does not provide useful data to predict REM dependency of OSAS.

  4. Beta and Gamma Gradients

    DEFF Research Database (Denmark)

    Løvborg, Leif; Gaffney, C. F.; Clark, P. A.;

    1985-01-01

    Experimental and/or theoretical estimates are presented concerning, (i) attenuation within the sample of beta and gamma radiation from the soil, (ii) the gamma dose within the sample due to its own radioactivity, and (iii) the soil gamma dose in the proximity of boundaries between regions...... of differing radioactivity. It is confirmed that removal of the outer 2 mm of sample is adequate to remove influence from soil beta dose and estimates are made of the error introduced by non-removal. Other evaluations include variation of the soil gamma dose near the ground surface and it appears...

  5. CHANG'E-2 lunar escape maneuvers to the Sun-Earth L2 libration point mission

    Science.gov (United States)

    Liu, Lei; Liu, Yong; Cao, Jianfeng; Hu, Songjie; Tang, Geshi; Xie, Jianfeng

    2014-01-01

    This paper addresses lunar escape maneuvers of the first Chinese Sun-Earth L2 libration point mission by the CHANG'E-2 satellite, which is also the world's first satellite to reach the L2 point from a lunar orbit. The lunar escape maneuvers are heavily constrained by the remaining propellant and the condition of telemetry, track and command, among others. First, these constraints are analyzed and summarized to design a target L2 Lissajous orbit and an initial transfer trajectory. Second, the maneuver mathematical models are studied. The multilevel maneuver schemes which consist of phasing maneuvers and a final lunar escape maneuver are designed for actual operations. Based on the scheme analysis and comparison, the 2-maneuver scheme with a 5.3-h-period phasing orbit is ultimately selected. Finally, the mission status based on the scheme is presented and the control operation results are discussed in detail. The methodology in this paper is especially beneficial and applicable to a future multi-mission instance in the deep space exploration.

  6. Precision Closed-Loop Orbital Maneuvering System Design and Performance for the Magnetospheric Multi-Scale Mission (MMS) Formation

    Science.gov (United States)

    Chai, Dean; Queen, Steve; Placanica, Sam

    2015-01-01

    NASA's Magnetospheric Multi-Scale (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.

  7. Application of hybrid methodology to rotors in steady and maneuvering flight

    Science.gov (United States)

    Rajmohan, Nischint

    Helicopters are versatile flying machines that have capabilities that are unparalleled by fixed wing aircraft, such as operating in hover, performing vertical takeoff and landing on unprepared sites. This makes their use especially desirable in military and search-and-rescue operations. However, modern helicopters still suffer from high levels of noise and vibration caused by the physical phenomena occurring in the vicinity of the rotor blades. Therefore, improvement in rotorcraft design to reduce the noise and vibration levels requires understanding of the underlying physical phenomena, and accurate prediction capabilities of the resulting rotorcraft aeromechanics. The goal of this research is to study the aeromechanics of rotors in steady and maneuvering flight using hybrid Computational Fluid Dynamics (CFD) methodology. The hybrid CFD methodology uses the Navier-Stokes equations to solve the flow near the blade surface but the effect of the far wake is computed through the wake model. The hybrid CFD methodology is computationally efficient and its wake modeling approach is nondissipative making it an attractive tool to study rotorcraft aeromechanics. Several enhancements were made to the CFD methodology and it was coupled to a Computational Structural Dynamics (CSD) methodology to perform a trimmed aeroelastic analysis of a rotor in forward flight. The coupling analyses, both loose and tight were used to identify the key physical phenomena that affect rotors in different steady flight regimes. The modeling enhancements improved the airloads predictions for a variety of flight conditions. It was found that the tightly coupled method did not impact the loads significantly for steady flight conditions compared to the loosely coupled method. The coupling methodology was extended to maneuvering flight analysis by enhancing the computational and structural models to handle non-periodic flight conditions and vehicle motions in time accurate mode. The flight test

  8. Benchmark Shock Tube Experiments for Radiative Heating Relevant to Earth Re-Entry

    Science.gov (United States)

    Brandis, A. M.; Cruden, B. A.

    2017-01-01

    Detailed spectrally and spatially resolved radiance has been measured in the Electric Arc Shock Tube (EAST) facility for conditions relevant to high speed entry into a variety of atmospheres, including Earth, Venus, Titan, Mars and the Outer Planets. The tests that measured radiation relevant for Earth re-entry are the focus of this work and are taken from campaigns 47, 50, 52 and 57. These tests covered conditions from 8 km/s to 15.5 km/s at initial pressures ranging from 0.05 Torr to 1 Torr, of which shots at 0.1 and 0.2 Torr are analyzed in this paper. These conditions cover a range of points of interest for potential fight missions, including return from Low Earth Orbit, the Moon and Mars. The large volume of testing available from EAST is useful for statistical analysis of radiation data, but is problematic for identifying representative experiments for performing detailed analysis. Therefore, the intent of this paper is to select a subset of benchmark test data that can be considered for further detailed study. These benchmark shots are intended to provide more accessible data sets for future code validation studies and facility-to-facility comparisons. The shots that have been selected as benchmark data are the ones in closest agreement to a line of best fit through all of the EAST results, whilst also showing the best experimental characteristics, such as test time and convergence to equilibrium. The EAST data are presented in different formats for analysis. These data include the spectral radiance at equilibrium, the spatial dependence of radiance over defined wavelength ranges and the mean non-equilibrium spectral radiance (so-called 'spectral non-equilibrium metric'). All the information needed to simulate each experimental trace, including free-stream conditions, shock time of arrival (i.e. x-t) relation, and the spectral and spatial resolution functions, are provided.

  9. Simulation-Based Analysis of Reentry Dynamics for the Sharp Atmospheric Entry Vehicle

    Science.gov (United States)

    Tillier, Clemens Emmanuel

    1998-01-01

    This thesis describes the analysis of the reentry dynamics of a high-performance lifting atmospheric entry vehicle through numerical simulation tools. The vehicle, named SHARP, is currently being developed by the Thermal Protection Materials and Systems branch of NASA Ames Research Center, Moffett Field, California. The goal of this project is to provide insight into trajectory tradeoffs and vehicle dynamics using simulation tools that are powerful, flexible, user-friendly and inexpensive. Implemented Using MATLAB and SIMULINK, these tools are developed with an eye towards further use in the conceptual design of the SHARP vehicle's trajectory and flight control systems. A trajectory simulator is used to quantify the entry capabilities of the vehicle subject to various operational constraints. Using an aerodynamic database computed by NASA and a model of the earth, the simulator generates the vehicle trajectory in three-dimensional space based on aerodynamic angle inputs. Requirements for entry along the SHARP aerothermal performance constraint are evaluated for different control strategies. Effect of vehicle mass on entry parameters is investigated, and the cross range capability of the vehicle is evaluated. Trajectory results are presented and interpreted. A six degree of freedom simulator builds on the trajectory simulator and provides attitude simulation for future entry controls development. A Newtonian aerodynamic model including control surfaces and a mass model are developed. A visualization tool for interpreting simulation results is described. Control surfaces are roughly sized. A simple controller is developed to fly the vehicle along its aerothermal performance constraint using aerodynamic flaps for control. This end-to-end demonstration proves the suitability of the 6-DOF simulator for future flight control system development. Finally, issues surrounding real-time simulation with hardware in the loop are discussed.

  10. Astronaut Thermal Exposure: Re-Entry After Low Earth Orbit Rescue Mission

    Science.gov (United States)

    Gillis, David B.; Hamilton, Douglas; Ilcus, Stana; Stepaniak, Phil; Son, Chang; Bue, Grant

    2009-01-01

    The STS-125 mission, launched May 11, 2009, is the final servicing mission to the Hubble Space Telescope. The repair mission's EVA tasks are described, including: installing a new wide field camera; installing the Cosmic Origins Spectrograph; repairing the Space Telescope Imaging Spectrograph; installing a new outer blanket layer; adding a Soft Capture and Rendezvous System for eventual controlled deorbit in about 2014; replacing the 'A' side Science Instrument Command and Data Handling module; repairing the Advanced Camera for surveys; and, replacing the rate sensor unit gyroscopes, fine guidance sensors and 3 batteries. Additionally, the Shuttle crew cabin thermal environment is described. A CFD model of per person CO2 demonstrates a discrepancy between crew breathing volume and general mid-deck levels of CO2. A follow-on CFD analysis of the mid-deck temperature distribution is provided. Procedural and engineering mitigation plans are presented to counteract thermal exposure upon reentry to the Earth atmosphere. Some of the procedures include: full cold soak the night prior to deorbit; modifying deck stowage to reduce interference with air flow; and early securing of avionics post-landing to reduce cabin thermal load prior to hatch opening. Engineering mitigation activities include modifying the location of the aft starboard ICUs, eliminating the X3 stack and eliminating ICU exhaust air directed onto astronauts; improved engineering data of ICU performance; and, verifying the adequacy of mid-deck temperature control using CFD models in addition to lumped parameter models. Post-mitigation CFD models of mid-deck temperature profiles and distribution are provided.

  11. Orbit determination and estimation of non-gravitational accelerations for the GOCE reentry phase

    Science.gov (United States)

    Visser, P. N. A. M.; van den IJssel, J. A. A.

    2016-11-01

    During its reentry phase from 21 October to 10 November 2013, the European Space Agency (ESA) Gravity field and steady-state Ocean Circulation Explorer (GOCE) continued to provide high-quality, dual-frequency observations by its Global Positioning System (GPS) receiver, star tracker and accelerometers. This resulted in a unique data set for testing high-precision orbit determination at altitudes down to as low as 137 km. In addition, the accelerometers kept working down to this altitude as well, be it with growing periods during which they were saturated. This made it possible to test the capability of estimating non-gravitational accelerations in high drag environments by GPS. A reduced-dynamic orbit determination based on an extended Kalman filter approach was adopted to cope with the estimation of the orbit parameters, including the exponentially growing non-gravitational accelerations. The orbits were found to be consistent with Satellite Laser Ranging (SLR) observations at a level of just a few centimeters for a few passes collected up to 2 November 2013. Also orbit overlap comparisons and comparisons with external orbit solutions indicate a 3-dimensional orbit quality at the dm level or better. In addition, high correlations were found between the estimated non-gravitational accelerations and those from the accelerometers during all periods when they were not saturated: typically close to 0.99 for the X axis of the gradiometer reference frame (close to the flight direction), for which the non-gravitational acceleration signal is by far the largest. High correlations were found as well for the Y axis (0.68-0.96) and Z axis (0.61-0.93), predominantly aligned with respectively the cross-track and height direction. The highest correlations were found for the last days, as long as the accelerometers were not saturated.

  12. [Sternal re-entry using the retractor for harvesting internal thoracic artery].

    Science.gov (United States)

    Niinami, H; Takeuchi, Y

    2002-06-01

    The number of redo cardiac operations, especially coronary artery bypass grafting (CABG), has recently been increasing mainly due to the failure of saphenous vein grafts. Re-opening a median sternotomy is troublesome, because of possible adhesion of the heart to the sternum. Preoperative computed tomography is quite useful and helpful in determining the degree of the adhesion of the heart and ascending aorta to the back of the sternum. We report here a safe and useful technique for sternal re-entry using a retractor for harvesting the internal thoracic artery (ITA). When re-opening a median sternotomy the incision is made to the sternal wires; the wires are then cut and removed. Small rake retractors, which are connected to the ITA retractor, are hooked to both ends of the left side of the sternum. The ITA retractor is gently wound up to lift up the sternum. An oscillating saw is then applied to divide the anterior table of the sternum. When the posterior table of the sternum is carefully divided, the left side of the sternum is automatically elevated slightly. Complete division of the sternum can be confirmed by this slight elevation. If the left side of the sternum is elevated a little bit more by the ITA retractor, the dissection of the adhesion between the sternum and the heart can be performed without assistance. This technique is most beneficial for a case of redo CABG with the use of the left ITA, but it can be applied in any patients who previously underwent median sternotomy.

  13. Applied Beta Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Rich, B.L.

    1986-01-01

    Measurements of beta and/or nonpenetrating exposure results is complicated and past techniques and capabilities have resulted in significant inaccuracies in recorded results. Current developments have resulted in increased capabilities which make the results more accurate and should result in less total exposure to the work force. Continued development of works in progress should provide equivalent future improvements.

  14. Beta Thalassemia (For Parents)

    Science.gov (United States)

    ... had their spleens removed. Slower growth rates. The anemia resulting from beta thalassemia can cause children to grow more slowly and also can lead ... boost production of new red blood cells. Some children with moderate anemia may require an occasional blood transfusion , particularly after ...

  15. Trichoderma .beta.-glucosidase

    Science.gov (United States)

    Dunn-Coleman, Nigel; Goedegebuur, Frits; Ward, Michael; Yao, Jian

    2006-01-03

    The present invention provides a novel .beta.-glucosidase nucleic acid sequence, designated bgl3, and the corresponding BGL3 amino acid sequence. The invention also provides expression vectors and host cells comprising a nucleic acid sequence encoding BGL3, recombinant BGL3 proteins and methods for producing the same.

  16. Roughing up Beta

    DEFF Research Database (Denmark)

    Bollerslev, Tim; Li, Sophia Zhengzi; Todorov, Viktor

    Motivated by the implications from a stylized equilibrium pricing framework, we investigate empirically how individual equity prices respond to continuous, or \\smooth," and jumpy, or \\rough," market price moves, and how these different market price risks, or betas, are priced in the cross-section...

  17. Early Mission Maneuver Operations for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

    Science.gov (United States)

    Roberts, Craig; Case, Sara; Reagoso, John; Webster, Cassandra

    2015-01-01

    The Deep Space Climate Observatory mission launched on February 11, 2015, and inserted onto a transfer trajectory toward a Lissajous orbit around the Sun-Earth L1 libration point. This paper presents an overview of the baseline transfer orbit and early mission maneuver operations leading up to the start of nominal science orbit operations. In particular, the analysis and performance of the spacecraft insertion, mid-course correction maneuvers, and the deep-space Lissajous orbit insertion maneuvers are discussed, com-paring the baseline orbit with actual mission results and highlighting mission and operations constraints..

  18. Aero-thermo-dynamic analysis of a low ballistic coefficient deployable capsule in Earth re-entry

    Science.gov (United States)

    Zuppardi, G.; Savino, R.; Mongelluzzo, G.

    2016-10-01

    The paper deals with a microsatellite and the related deployable recovery capsule. The aero-brake is folded at launch and deployed in space and is able to perform a de-orbiting controlled re-entry. This kind of capsule, with a flexible, high temperature resistant fabric, thanks to its lightness and modulating capability, can be an alternative to the current "conventional" recovery capsules. The present authors already analyzed the trajectory and the aerodynamic behavior of low ballistic coefficient capsules during Earth re-entry and Mars entry. In previous studies, aerodynamic longitudinal stability analysis and evaluation of thermal and aerodynamic loads for a possible suborbital re-entry demonstrator were carried out in both continuum and rarefied regimes. The present study is aimed at providing preliminary information about thermal and aerodynamic loads and longitudinal stability for a similar deployable capsule, as well as information about the electronic composition of the plasma sheet and its possible influence on radio communications at the altitudes where GPS black-out could occur. Since the computer tests were carried out at high altitudes, therefore in rarefied flow fields, use of Direct Simulation Monte Carlo codes was mandatory. The computations involved both global aerodynamic quantities (drag and longitudinal moment coefficients) and local aerodynamic quantities (heat flux and pressure distributions along the capsule surface). The results verified that the capsule at high altitude (150 km) is self-stabilizing; it is stable around the nominal attitude or at zero angle of attack and unstable around the reverse attitude or at 180° angle of attack. The analysis also pointed out the presence of extra statically stable equilibrium trim points.

  19. TGF-beta and osteoarthritis.

    NARCIS (Netherlands)

    Blaney Davidson, E.N.; Kraan, P.M. van der; Berg, W.B. van den

    2007-01-01

    OBJECTIVE: Cartilage damage is a major problem in osteoarthritis (OA). Growth factors like transforming growth factor-beta (TGF-beta) have great potential in cartilage repair. In this review, we will focus on the potential therapeutic intervention in OA with TGF-beta, application of the growth facto

  20. E2F-dependent induction of p14ARF during cell cycle re-entry in human T cells

    DEFF Research Database (Denmark)

    del Arroyo, Ana Gutierrez; El Messaoudi, Selma; Clark, Paula A

    2007-01-01

    The ARF protein, encoded by alternate exon usage within the CDKN2A locus, provides a link between the retinoblastoma (pRb) and p53 tumor suppressor pathways. Agents that disable pRb or otherwise impinge on the E2F family of transcription factors induce expression of ARF, resulting in stabilization...... of p53 and activation of p53-regulated genes. However, in some cell types ARF is not induced upon cell cycle re-entry, as expected of a conventional E2F target gene, leading to the suggestion that the ARF promoter only responds to supra-physiological or aberrant levels of E2F. These properties have...

  1. Differential regulation of chemoattractant-stimulated beta 2, beta 3, and beta 7 integrin activity.

    Science.gov (United States)

    Sadhu, C; Masinovsky, B; Staunton, D E

    1998-06-01

    Leukocyte adhesion to endothelium and extravasation are dynamic processes that require activation of integrins. Chemoattractants such as IL-8 and FMLP are potent activators of leukocyte integrins. To compare the chemoattractant-stimulated activation of three integrins, alpha 4 beta 7, alpha L beta 2, and alpha V beta 3, in the same cellular context, we expressed an IL-8 receptor (IL-8RA) and FMLP receptor (FPR) in the lymphoid cell line JY. Chemoattractants induced a rapid increase in alpha L beta 2- and alpha V beta 3-dependent JY adhesion within 5 min, and it was sustained for 30 min. In contrast, stimulation of alpha 4 beta 7-dependent adhesion was transient, returning to basal levels by 30 min. The activation profiles of the integrins were similar regardless of whether IL-8 or FMLP was used for induction. We also demonstrate that alpha 4 beta 7-dependent adhesion was uniquely responsive to the F actin-disrupting agent cytochalasin D and the protein kinase C (PKC) inhibitor chelerythrin. While alpha V beta 3- and alpha L beta 2-mediated cell adhesion was significantly reduced by cytochalasin D, alpha 4 beta 7-mediated adhesion was enhanced. Chelerythrin inhibited both the IL-8 and PMA activation of alpha L beta 2 and alpha V beta 3. In contrast, inducible alpha 4 beta 7 activity was unaffected, and basal activity was increased. These findings demonstrate that the mechanism of alpha 4 beta 7 regulation by chemoattractants is different from that of alpha L beta 2 and alpha V beta 3 and that it appears to involve distinct cytoskeletal and PKC dependencies. In addition, PKC activity may be a positive or negative regulator of integrin-dependent adhesion.

  2. Design of a Robotic System to Measure Propulsion Work of Over-Ground Wheelchair Maneuvers.

    Science.gov (United States)

    Liles, Howard; Huang, Morris; Caspall, Jayme; Sprigle, Stephen

    2015-11-01

    A wheelchair-propelling robot has been developed to measure the efficiency of manual wheelchairs. The use of a robot has certain advantages compared to the use of human operators with respect to repeatability of measurements and the ability to compare many more wheelchair configurations than possible with human operators. Its design and implementation required significant engineering and validation of hardware and control systems. The robot can propel a wheelchair according to pre-programmed accelerations and velocities and measures the forces required to achieve these maneuvers. Wheel velocities were within 0.1 m/s of programmed values and coefficients of variation . Torque measurements were also repeatable with . By determining the propulsion torque required to propel the wheelchair through a series of canonical maneuvers, task-dependent input work for various wheelchairs and configurations can be compared. This metric would serve to quantify the combined inertial and frictional resistance of the mechanical system.

  3. Flight-Like Ground Demonstrations of Precision Maneuvers for Spacecraft Formations

    Science.gov (United States)

    Scharf, Daniel P.; Hadaegh, Fred Y.; Keim, Jason A.; Morfopoulos, Arin C.; Ahmed, Asif; Brenman, Yan; Vafaei, Ali; Shields, Joel F.; Bergh, Charles F.; Lawson, Peter R.

    2008-01-01

    Synchronized formation rotations are a common maneuver for planned precision formations. In such a rotation, attitudes remain synchronized with relative positions, as if the spacecraft were embedded in a virtual rigid body. Further, since synchronized rotations are needed for science data collection, this maneuver requires the highest precision control of formation positions and attitudes. A recently completed, major technology milestone for the Terrestrial Planet Finder Interferometer is the high-fidelity, ground demonstration of precision synchronized formation rotations. These demonstrations were performed in the Formation Control Testbed (FCT), which is a flight-like, multi-robot formation testbed. The FCT is briefly introduced, and then the synchronized rotation demonstration results are presented. An initial error budget consisting of formation simulations is used to show the connection between ground performance and TPF-I flight performance.

  4. A Novel Concept for Guidance and Control of Spacecraft Orbital Maneuvers

    Directory of Open Access Journals (Sweden)

    Matteo Dentis

    2016-01-01

    Full Text Available The purpose of this paper is the design of guidance and control algorithms for orbital space maneuvers. A 6-dof orbital simulator, based on Clohessy-Wiltshire-Hill equations, is developed in C language, considering cold gas reaction thrusters and reaction wheels as actuation system. The computational limitations of on-board computers are also included. A combination of guidance and control algorithms for an orbital maneuver is proposed: (i a suitably designed Zero-Effort-Miss/Zero-Effort-Velocity (ZEM/ZEV algorithm is adopted for the guidance and (ii a linear quadratic regulator (LQR is used for the attitude control. The proposed approach is verified for different cases, including external environment disturbances and errors on the actuation system.

  5. Implementation of the Orbital Maneuvering Systems Engine and Thrust Vector Control for the European Service Module

    Science.gov (United States)

    Millard, Jon

    2014-01-01

    The European Space Agency (ESA) has entered into a partnership with the National Aeronautics and Space Administration (NASA) to develop and provide the Service Module (SM) for the Orion Multipurpose Crew Vehicle (MPCV) Program. The European Service Module (ESM) will provide main engine thrust by utilizing the Space Shuttle Program Orbital Maneuvering System Engine (OMS-E). Thrust Vector Control (TVC) of the OMS-E will be provided by the Orbital Maneuvering System (OMS) TVC, also used during the Space Shuttle Program. NASA will be providing the OMS-E and OMS TVC to ESA as Government Furnished Equipment (GFE) to integrate into the ESM. This presentation will describe the OMS-E and OMS TVC and discuss the implementation of the hardware for the ESM.

  6. Active control of tiltrotor blade in-plane loads during maneuvers

    Science.gov (United States)

    Miller, David G.; Ham, Norman D.

    1988-01-01

    The origin of one/rev rotor aerodynamic loads which arise in tiltrotor aircraft during airplane-mode high speed pull-up and push-over maneuvers is examined using a coupled rotor/fuselage dynamic simulation. A modified eigenstructure assignment technique is used to design a controller which alleviates the in-plane loads during high pitch rate maneuvers. The controller utilizes rotor cyclic pitch inputs to restructure the aircraft short period and phugoid responses in order to achieve the coupling between pitch rate and rotor flapping responses which minimizes the rotor aerodynamic loading. Realistic time delays in the feedback path are considered during the controller design. Stability robustness in the presence of high frequency modeling errors is ensured through the use of singular value analysis.

  7. Trajectory and Correction Maneuver During the Transfer from Earth to Halo Orbit

    Institute of Scientific and Technical Information of China (English)

    Xu Ming; Xu Shijie

    2008-01-01

    This article addresses the design of the trajectory transferring fi'om Earth to Halo orbit,and proposes a timing closed-loop strategy of correction maneuver during the trausfer in the frame of circular restricted three body problem (CR3BP).The relation between the Floquet multipliers and the magnitudes of Halo orbit is established,so that the suitable magnitude for the aerospace mission is chosen in previous researches,and six types of single-impulse transfer trajectories are attained from the geometry of the invariant manifolds.Based on one of the trajectories of indirect transfer which arc ignored in the most of literatures,the stochastic control theory for imperfect information of the discrete linear stochastic system is applied to design the trajectory correction maneuver.The statistical dispersion analysis is performed by Monte-Carlo simulation.

  8. Purging using the Heimlich maneuver among children and adolescents with eating disorders.

    Science.gov (United States)

    Boachie, Ahmed; Kusi Appiah, Edigna; Jubin, Michelle; Jasper, Karin

    2015-09-01

    This case report describes five independent cases of children and adolescents assessed for eating disorders who disclosed using the Heimlich maneuver as a purging technique. The maneuver is meant to be used only in life or death situations, likely once or less in any person's lifetime. A child or adolescent with an eating disorder may be using it to self-induce vomiting on a daily basis, increasing the risk of complications, including potential damage to major organs of the body. Asking patients who purge to elaborate on the methods with which they purge can provide clinicians with fuller information, improving their ability to select appropriate medical tests and interventions. Thorough investigations of physical complaints during the patient assessment may be warranted, including examining patients for possible rib fractures, hemorrhages, perforations of the hollow viscous, and other forms of blunt abdominal traumas.

  9. Analysis of LFM-waveform Libraries for Cognitive Tracking Maneuvering Targets

    Directory of Open Access Journals (Sweden)

    Wang Hongyan

    2016-01-01

    Full Text Available Based on the idea of the waveform agility in cognitive radars,the waveform libraries for maneuvering target tracking are discussed. LFM-waveform libraries are designed according to different combinations of chirp parameters and FrFT rotation angles. By applying the interact multiple model (IMM algorithm in tracking maneuvering targets, transmitted waveform is called real time from the LFM-waveform libraries. The waveforms are selected from the library according to the criterion of maximum mutual information between the current state of knowledge of the model and the measurement. Simulation results show that waveform library containing certain amount LFM-waveforms can improve the performance of cognitive tracking radar.

  10. Axial offset as measure of stability of light water nuclear reactor during capacity maneuvering

    Directory of Open Access Journals (Sweden)

    Mark V. Nikolsky

    2015-03-01

    Full Text Available High reliability and security of power unit are required during operation of power unit while maneuvering. They depend on the stability of reactor when transition from one power level to another. The axial offset is a quantitative measure of the reactor stability. It is shown that change of the active core inlet coolant temperature yields an uncontrollable disturbance affecting the axial offset and therefore the reactor stability. To insure the reactor stability the compromise-combined power control method is proposed. Analysis of the influence of temperature of coolant at the magnitude of the axial offset for different regulatory programs is carried out. The change in the depth of immersion of regulators in the active zone for different regulatory programs when the reactor plant daily capacity maneuver is studied.

  11. Persistent Direction-Fixed Nystagmus Following Canalith Repositioning Maneuver for Horizontal Canal BPPV: A Case of Canalith Jam.

    Science.gov (United States)

    Chang, Young-Soo; Choi, Jeesun; Chung, Won-Ho

    2014-06-01

    The authors report a 64-year-old man who developed persistent direction fixed nystagmus after a canalith repositioning maneuver for horizontal canal benign paroxysmal positional vertigo (HC-BPPV). The patient was initially diagnosed with right HC-BPPV given that the Dix-Hallpike test showed geotropic horizontal nystagmus that was more pronounced on the right side, although the roll test did not show any positional nystagmus. The patient was treated with a canalith repositioning maneuver (Lempert maneuver). The next day, the patient experienced a different character of dizziness, and left-beating spontaneous nystagmus regardless of head position was observed. After a forced prolonged left decubitus and frequent head shaking, his symptoms and nystagmus resolved. This condition, referred to as canalith jam, can be a complication after the repositioning maneuver in patients with BPPV. Atypical positional tests suggest that abnormal canal anatomy could be the underlying cause of canalith jam.

  12. Observability analysis of 2D single-beacon navigation in the presence of constant currents for two classes of maneuvers

    Digital Repository Service at National Institute of Oceanography (India)

    Crasta, N.; Bayat, M.; Aguiar, A.P.; Pascoal, A.M.

    We analyze the observability properties of an underwater vehicle (moving in 2D) performing single beacon navigation for two specic classes of maneuvers, whereby the vehicle measures its distance to a xed transponder located at a known position using...

  13. Know Before You Do: Anticipating Maneuvers via Learning Temporal Driving Models

    Science.gov (United States)

    2015-04-01

    features/index.htm. Accessed: 2014-09-30. [3] Google self driving car . http://en.wikipedia.org/wiki/ Google driverless car . Accessed: 2014-10-11. [4...anticipation a challenging problem. In this work we anticipate driving maneuvers a few seconds before they occur. For this purpose we equip a car with...cameras and a computing device to capture the context from both inside and outside of the car . We represent the context with expressive features and

  14. Near Real-Time Closed-Loop Optimal Control Feedback for Spacecraft Attitude Maneuvers

    Science.gov (United States)

    2009-03-01

    for Formation Flying Spacecraft. Navigation: Journal of the Institute of Navigation, 45(3):195–207, 1996. 133 18. N. G. Creamer , G. Kirby, R. Weber...Kennel. A Satellite Motion Simulator. Astronautics, 5:22–23, 90–91, 1960. 28. Martin Hepperle. http://www.mh-aerotools.de/airfoils/propuls3.htm. In...F. Li, M. Bainum, N. G Creamer , and S. Fisher. Rapid Reorientation Maneuvers of Experimental Spacecraft with a Pendulum Appendage. Journal of Guidance

  15. Operational Maneuver From the Sea: Reducing the Need for Battlespace Dominance in the Littoral Regions.

    Science.gov (United States)

    2007-11-02

    to conduct a joint "operational maneuver from the sea and air." The Integrated Battle Organization ( IBO ) is a new C2 concept, developed by the Naval... IBO has a flat, vice hierarchical, organizational structure.43 It resembles and meshes nicely with the JTF C2 structure. Although still under...development and evaluation, the IBO is a huge step in the right direction. In order for OMFTS to work more effectively in a joint arena, a standard flexible

  16. In-shoe plantar tri-axial stress profiles during maximum-effort cutting maneuvers.

    Science.gov (United States)

    Cong, Yan; Lam, Wing Kai; Cheung, Jason Tak-Man; Zhang, Ming

    2014-12-18

    Soft tissue injuries, such as anterior cruciate ligament rupture, ankle sprain and foot skin problems, frequently occur during cutting maneuvers. These injuries are often regarded as associated with abnormal joint torque and interfacial friction caused by excessive external and in-shoe shear forces. This study simultaneously investigated the dynamic in-shoe localized plantar pressure and shear stress during lateral shuffling and 45° sidestep cutting maneuvers. Tri-axial force transducers were affixed at the first and second metatarsal heads, lateral forefoot, and heel regions in the midsole of a basketball shoe. Seventeen basketball players executed both cutting maneuvers with maximum efforts. Lateral shuffling cutting had a larger mediolateral braking force than 45° sidestep cutting. This large braking force was concentrated at the first metatarsal head, as indicated by its maximum medial shear stress (312.2 ± 157.0 kPa). During propulsion phase, peak shear stress occurred at the second metatarsal head (271.3 ± 124.3 kPa). Compared with lateral shuffling cutting, 45° sidestep cutting produced larger peak propulsion shear stress (463.0 ± 272.6 kPa) but smaller peak braking shear stress (184.8 ± 181.7 kPa), of which both were found at the first metatarsal head. During both cutting maneuvers, maximum medial and posterior shear stress occurred at the first metatarsal head, whereas maximum pressure occurred at the second metatarsal head. The first and second metatarsal heads sustained relatively high pressure and shear stress and were expected to be susceptible to plantar tissue discomfort or injury. Due to different stress distribution, distinct pressure and shear cushioning mechanisms in basketball footwear might be considered over different foot regions.

  17. Safe Certificate-Based Maneuvers for Teams of Quadrotors Using Differential Flatness

    OpenAIRE

    Wang, Li; Ames, Aaron D.; Egerstedt, Magnus

    2017-01-01

    Safety Barrier Certificates that ensure collision-free maneuvers for teams of differential flatness-based quadrotors are presented in this paper. Synthesized with control barrier functions, the certificates are used to modify the nominal trajectory in a minimally invasive way to avoid collisions. The proposed collision avoidance strategy complements existing flight control and planning algorithms by providing trajectory modifications with provable safety guarantees. The effectiveness of this ...

  18. Bearings-only fusion tracking for maneuvering target with wavelet transform in three dimensional space

    Institute of Scientific and Technical Information of China (English)

    Tian Hongwei; Jing Zhongliang; Hu Shiqiang; Li Jianxun

    2005-01-01

    A new fusion tracking algorithm is presented to track maneuvering target in three-dimensional (3D) space with bearings-only measurements. With the introduction of passive location and interacting multiple model (IMM) algorithm based on multirate model, the high-rate sequence measurements of two sensors are utilized. Simulation results show that the performance of tracking has been improved. The new algorithm removes the barrier of processing high-rate bearingsonly measurements.

  19. Ecology of mule deer on the Pinon Canyon Maneuver Site, Colorado

    OpenAIRE

    Gerlach, Thomas P.

    1987-01-01

    Mule deer (Odocoileus hemionus) population dynamics, movements, and habitat use were studied on the Pinon Canyon Maneuver Site in southeastern Colorado during January 1983- December 1984. Thirty-eight adults and 28 fawns were radio collared, and 35 adults were color collared or ear tagged. Population estimates were 365 and 370 deer for 1983 and 1984, respectively. The sex ratio (yearling and adult) was 60 males: 100 females. Adult female pregnancy rate was 95%; the mean litter ...

  20. Road Friction Estimation under Complicated Maneuver Conditions for Active Yaw Control

    Institute of Scientific and Technical Information of China (English)

    LI Liang; LI Hongzhi; SONG Jian; YANG Cai; WU Hao

    2009-01-01

    Road friction coefficient is a key factor for the stability control of the vehicle dynamics in the critical conditions. Obviously the vehicle dynamics stability control systems, including the anti-lock brake system(ABS), the traction control system(TCS), and the active yaw control(AYC) system, need the accurate tire and road friction information. However, the simplified method based on the linear tire and vehicle model could not obtain the accurate road friction coefficient for the complicated maneuver of the vehicle. Because the active braking control mode of AYC is different from that of ABS, the road friction coefficient cannot be estimated only with the dynamics states of the tire. With the related dynamics states measured by the sensors of AYC, a comprehensive strategy of the road friction estimation for the active yaw control is brought forward with the sensor fusion technique. Firstly, the variations of the dynamics characteristics of vehicle and tire, and the stability control mode in the steering process are considered, and then the proper road friction estimation methods are brought forward according to the vehicle maneuver process. In the steering maneuver without braking, the comprehensive road friction from the four wheels may be estimated based on the multi-sensor signal fusion method. The estimated values of the road friction reflect the road friction characteristic. When the active brake involved, the road friction coefficient of the braked wheel may be estimated based on the brake pressure and tire forces, the estimated values reflect the road friction between the braked wheel and the road. So the optimal control of the wheel slip rate may be obtained according to the road friction coefficient. The methods proposed in the paper are integrated into the real time controller of AYC, which is matched onto the test vehicle. The ground tests validate the accuracy of the proposed method under the complicated maneuver conditions.

  1. An Expedite Approximate Algorithm for Calculating the Controls in the Longitudinal Maneuver

    OpenAIRE

    Laurentiu MORARU

    2015-01-01

    This paper discusses an expedite approximate algorithm for obtaining the controls in the longitudinal maneuver of the aerospace vehicles. The equations of motion are written in terms of the flight path (the trajectory that is desired is also given in terms of flight path, that is the local radius of curvature is given as a function of flight path) and the controls required for following a desired trajectory obtained accordingly. A finite terms integration procedure is subsequently presented.

  2. Rapid maneuvering of multi-body dynamic systems with optimal motion compensation

    Science.gov (United States)

    Bishop, B.; Gargano, R.; Sears, A.; Karpenko, M.

    2015-12-01

    Rapid maneuvering of multi-body dynamical systems is an important, yet challenging, problem in many applications. Even in the case of rigid bodies, it can be difficult to maintain precise control over nominally stationary links if it is required to move some of the other links quickly because of the various nonlinearities and coupled interactions that occur between the bodies. Typical control concepts treat the multi-body motion control problem in two-stages. First, the nonlinear and coupling terms are treated as disturbances and a trajectory tracking control law is designed in order to attenuate their effects. Next, motion profiles are designed, based on kinematics parameterizations, and these are used as inputs to the closed loop system to move the links. This paper describes an approach for rapid maneuvering of multi-body systems that uses optimal control theory to account for dynamic nonlinearities and coupling as part of the motion trajectory design. Incorporating appropriate operational constraints automatically compensates for these multi-body effects so that motion time can be reduced while simultaneously achieving other objectives such as reducing the excitation of selected links. Since the compensatory effect is embedded within the optimal motion trajectories, the performance improvement can be obtained even when using simple closed-loop architectures for maneuver implementation. Simulation results for minimum time control of a two-axis gimbal system and for rapid maneuvering of a TDRS single-access antenna, wherein it is desired to limit the excitation of the satellite body to which the antenna is attached, are presented to illustrate the concepts.

  3. The role of the thoracic compression reflex in the Heimlich Maneuver.

    Science.gov (United States)

    Crawford, L M; Emmett, J W

    1977-01-01

    Using the dog as an experimental model, the relationship of the Thoracic Compression Reflex (TCR) to the Heimlich Maneuver (HM) was examined. TCR was equally effective as lateral chest compression in relieving artificially induced choke. Destruction of the TCR by vagotomy rendered relief of choke by HM ineffectual in 5 of 8 dogs. It was concluded TCR may be a factor in HM, but that mechanical compression of the lungs is also involved.

  4. Metrics for Assessing Cognitive Skills in the Maneuver Captains Career Course

    Science.gov (United States)

    2009-01-01

    Bethesda, MD: Management Research Institute, Inc. Appendix A COMPANY-LEVEL STUDENT ASSESMENT PACKAGE MANEUVER CAPTAINS CAREER COURSE...and smoke to remain effective for extended periods in both day and night. Prevailing winds do not favor our use of vehicle delivered smoke . Clear...Yellow smoke primary, Green smoke alternate; marks friendly line of troops for CAS. WARNO #2 TO OPORD 08-12 A-26 ACKNOWLEDGE: SMITH

  5. A control strategy for steering an autonomous surface sailing vehicle in a tacking maneuver

    OpenAIRE

    2009-01-01

    Sailing vessels such as sailboats but also landyachts are vehicles representing a real challenge for automation. However, the control aspects of such vehicles were hitherto very little studied. This paper presents a simplied dynamic model of a so-called landyacht allowing to capture the main elements of the behavior of surface sailing vessels. We then propose a path generation scheme and a controller design for a well-known and fundamental maneuver in sailing referred to as tacking. Simulatio...

  6. The Prospect of Responsive Spacecraft Using Aeroassisted, Trans-Atmospheric Maneuvers

    Science.gov (United States)

    2014-06-19

    McNish, “Latitude and Longitude,” RASC Calgary Centre, The Royal Astronomical Society of Canada, last modified 11 November 2011, accessed 17 August...maintains the prerogative of performing as many exo- or trans-atmospheric maneuvers as permitted by the ∆ capacity of the vehicle. Consequently, the...Wright-Patterson AFB, OH, March 2004 (ADA424074). McNish, Larry. “Latitude and Longitude.” RASC Calgary Centre, The Royal Astronomical Society

  7. A New Approach to Satisfy Dynamic Similarity for Model Submarine Maneuvers

    Science.gov (United States)

    2007-11-28

    scale jam recovery, a steady approach speed is required for RCM correlation maneuvers. The scaled model approach speed must be set at 21 U.n0 . UsO (33...NAVSEA 05H Y M. King 1 ONR 331 Y R. Joslin 1 NSWCCD 3452 Y TIC (C) 1 NSWCCD 5060 Y D. Walden 1 NSWCCD 5080 Y J. Brown 1 NSWCCD 5080 Y B. Cox 1 NSWCCD 5400 Y

  8. Transfer Maneuvers Between Periodic Earth-Moon Orbits Using Stable an Unstable Manifolds

    Science.gov (United States)

    Marcuzzi, J. P.; Leiva, A. M.; Briozzo, C. B.

    In this paper we have determined the stable and unstable manifold of six unstable periodic orbits (h=-1,586656) in an appropriate surface of section in the Earth-Moon coplanar circular restricted three body problem. The cost diagrams give account of a low transfer tax on using this technique and they would allow to determine the lower cost regions in order to apply the required propellent in each maneuver. FULL TEXT IN SPANISH

  9. Beta-thalassemia

    Directory of Open Access Journals (Sweden)

    Origa Raffaella

    2010-05-01

    Full Text Available Abstract Beta-thalassemias are a group of hereditary blood disorders characterized by anomalies in the synthesis of the beta chains of hemoglobin resulting in variable phenotypes ranging from severe anemia to clinically asymptomatic individuals. The total annual incidence of symptomatic individuals is estimated at 1 in 100,000 throughout the world and 1 in 10,000 people in the European Union. Three main forms have been described: thalassemia major, thalassemia intermedia and thalassemia minor. Individuals with thalassemia major usually present within the first two years of life with severe anemia, requiring regular red blood cell (RBC transfusions. Findings in untreated or poorly transfused individuals with thalassemia major, as seen in some developing countries, are growth retardation, pallor, jaundice, poor musculature, hepatosplenomegaly, leg ulcers, development of masses from extramedullary hematopoiesis, and skeletal changes that result from expansion of the bone marrow. Regular transfusion therapy leads to iron overload-related complications including endocrine complication (growth retardation, failure of sexual maturation, diabetes mellitus, and insufficiency of the parathyroid, thyroid, pituitary, and less commonly, adrenal glands, dilated myocardiopathy, liver fibrosis and cirrhosis. Patients with thalassemia intermedia present later in life with moderate anemia and do not require regular transfusions. Main clinical features in these patients are hypertrophy of erythroid marrow with medullary and extramedullary hematopoiesis and its complications (osteoporosis, masses of erythropoietic tissue that primarily affect the spleen, liver, lymph nodes, chest and spine, and bone deformities and typical facial changes, gallstones, painful leg ulcers and increased predisposition to thrombosis. Thalassemia minor is clinically asymptomatic but some subjects may have moderate anemia. Beta-thalassemias are caused by point mutations or, more rarely

  10. Beta-thalassemia.

    Science.gov (United States)

    Galanello, Renzo; Origa, Raffaella

    2010-05-21

    Beta-thalassemias are a group of hereditary blood disorders characterized by anomalies in the synthesis of the beta chains of hemoglobin resulting in variable phenotypes ranging from severe anemia to clinically asymptomatic individuals. The total annual incidence of symptomatic individuals is estimated at 1 in 100,000 throughout the world and 1 in 10,000 people in the European Union. Three main forms have been described: thalassemia major, thalassemia intermedia and thalassemia minor. Individuals with thalassemia major usually present within the first two years of life with severe anemia, requiring regular red blood cell (RBC) transfusions. Findings in untreated or poorly transfused individuals with thalassemia major, as seen in some developing countries, are growth retardation, pallor, jaundice, poor musculature, hepatosplenomegaly, leg ulcers, development of masses from extramedullary hematopoiesis, and skeletal changes that result from expansion of the bone marrow. Regular transfusion therapy leads to iron overload-related complications including endocrine complication (growth retardation, failure of sexual maturation, diabetes mellitus, and insufficiency of the parathyroid, thyroid, pituitary, and less commonly, adrenal glands), dilated myocardiopathy, liver fibrosis and cirrhosis). Patients with thalassemia intermedia present later in life with moderate anemia and do not require regular transfusions. Main clinical features in these patients are hypertrophy of erythroid marrow with medullary and extramedullary hematopoiesis and its complications (osteoporosis, masses of erythropoietic tissue that primarily affect the spleen, liver, lymph nodes, chest and spine, and bone deformities and typical facial changes), gallstones, painful leg ulcers and increased predisposition to thrombosis. Thalassemia minor is clinically asymptomatic but some subjects may have moderate anemia. Beta-thalassemias are caused by point mutations or, more rarely, deletions in the beta

  11. Beta and muon decays

    Energy Technology Data Exchange (ETDEWEB)

    Galindo, A.; Pascual, P.

    1967-07-01

    These notes represent a series of lectures delivered by the authors in the Junta de Energia Nuclear, during the Spring term of 1965. They were devoted to graduate students interested in the Theory of Elementary Particles. Special emphasis was focussed into the computational problems. Chapter I is a review of basic principles (Dirac equation, transition probabilities, final state interactions.) which will be needed later. In Chapter II the four-fermion punctual Interaction is discussed, Chapter III is devoted to the study of beta-decay; the main emphasis is given to the deduction of the formulae corresponding to electron-antineutrino correlation, electron energy spectrum, lifetimes, asymmetry of electrons emitted from polarized nuclei, electron and neutrino polarization and time reversal invariance in beta decay. In Chapter IV we deal with the decay of polarized muons with radiative corrections. Chapter V is devoted to an introduction to C.V.C. theory. (Author)

  12. Realized Beta GARCH

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger; Voev, Valeri Radkov

    2014-01-01

    We introduce a multivariate generalized autoregressive conditional heteroskedasticity (GARCH) model that incorporates realized measures of variances and covariances. Realized measures extract information about the current levels of volatilities and correlations from high-frequency data, which...... is particularly useful for modeling financial returns during periods of rapid changes in the underlying covariance structure. When applied to market returns in conjunction with returns on an individual asset, the model yields a dynamic model specification of the conditional regression coefficient that is known...... as the beta. We apply the model to a large set of assets and find the conditional betas to be far more variable than usually found with rolling-window regressions based exclusively on daily returns. In the empirical part of the paper, we examine the cross-sectional as well as the time variation...

  13. Hemodynamic responses during and after multiple sets of stretching exercises performed with and without the Valsalva maneuver

    OpenAIRE

    Lima,Tainah P.; Paulo T.V. Farinatti; Ercole C. Rubini; Silva, Elirez B.; Monteiro, Walace D.

    2015-01-01

    OBJECTIVE: This study investigated the acute hemodynamic responses to multiple sets of passive stretching exercises performed with and without the Valsalva maneuver. METHODS: Fifteen healthy men aged 21 to 29 years with poor flexibility performed stretching protocols comprising 10 sets of maximal passive unilateral hip flexion, sustained for 30 seconds with equal intervals between sets. Protocols without and with the Valsalva maneuver were applied in a random counterbalanced order, separated ...

  14. Breathing Maneuvers as a Vasoactive Stimulus for Detecting Inducible Myocardial Ischemia – An Experimental Cardiovascular Magnetic Resonance Study

    Science.gov (United States)

    Fischer, Kady; Guensch, Dominik P; Shie, Nancy; Lebel, Julie; Friedrich, Matthias G

    2016-01-01

    Background Breathing maneuvers can elicit a similar vascular response as vasodilatory agents like adenosine; yet, their potential diagnostic utility in the presence of coronary artery stenosis is unknown. The objective of the study is to investigate if breathing maneuvers can non-invasively detect inducible ischemia in an experimental animal model when the myocardium is imaged with oxygenation-sensitive cardiovascular magnetic resonance (OS-CMR). Methods and Findings In 11 anesthetised swine with experimentally induced significant stenosis (fractional flow reserve coronary artery (LAD) and 9 control animals, OS-CMR at 3T was performed during two different breathing maneuvers, a long breath-hold; and a combined maneuver of 60s of hyperventilation followed by a long breath-hold. The resulting change of myocardial oxygenation was compared to the invasive measurements of coronary blood flow, blood gases, and oxygen extraction. In control animals, all breathing maneuvers could significantly alter coronary blood flow as hyperventilation decreased coronary blood flow by 34±23%. A long breath-hold alone led to an increase of 97±88%, while the increase was 346±327% (pcoronary blood flow response was attenuated after both hyperventilation and the following breath-hold. This was matched by the observed oxygenation response as breath-holds following hyperventilation consistently yielded a significant difference in the signal of the MRI images between the perfusion territory of the stenosis LAD and remote myocardium. There was no difference between the coronary territories during the other breathing maneuvers or in the control group at any point. Conclusion In an experimental animal model, the response to a combined breathing maneuver of hyperventilation with subsequent breath-holding is blunted in myocardium subject to significant coronary artery stenosis. This maneuver may allow for detecting severe coronary artery stenosis and have a significant clinical potential as a

  15. NO-sensitive guanylyl cyclase beta1 subunit is peripherally associated to chromosomes during mitosis. Novel role in chromatin condensation and cell cycle progression.

    Science.gov (United States)

    Pifarré, Paula; Baltrons, María Antonia; Földi, Istvan; García, Agustina

    2009-01-01

    NO-sensitive guanylyl cyclase (GC(NO)), the major NO target, is involved in important regulatory functions in the cardiovascular, gastrointestinal and central nervous systems. GC(NO) exists as heterodimers of alpha(1/2) and beta1 subunits. Deletion of the obligate beta1 dimerizing partner abrogates NO/cGMP signaling and shortens the life span of KO mice. Localization studies in the CNS have shown that beta1 is more widespread than alpha subunits and in some areas is the only GC(NO) subunit expressed, suggesting that beta1 may have GC(NO)-independent functions. GC(NO) is predominantly cytosolic, but association to membranes and other intracellular structures has been described. Here, we show localization of beta1 in cytoplasm and nucleus of cells expressing alpha subunits and GC(NO) activity (astrocytes, C6 cells), as well as in cells devoid of alpha subunits and GC(NO) activity (microglia). In both cell types beta1 associates peripherally to chromosomes in all phases of mitosis. Immunodepletion of beta1 in C6 cells enhances chromatin condensation in an in vitro assay. Moreover, silencing beta1 by siRNA induces cell cycle re-entry as determined by flow cytometry, and increases proliferation rate in a MTT-assay, whereas infection with beta1-containing adenovirus has the opposite effect. These actions are independent of cGMP formation. We postulate that beta1 is a multifunctional protein that regulates chromatin condensation and cell cycle progression, in addition to being an obligate monomer in functional GC(NO) heterodimers.

  16. Impact of cerebral cardiopulmonary resuscitation maneuvers in a general hospital: prognostic factors and outcomes

    Directory of Open Access Journals (Sweden)

    Bartholomay Eduardo

    2003-01-01

    Full Text Available OBJECTIVE: To assess survival of patients undergoing cerebral cardiopulmonary resuscitation maneuvers and to identify prognostic factors for short-term survival. METHODS: Prospective study with patients undergoing cardiopulmonary resuscitation maneuvers. RESULTS: The study included 150 patients. Spontaneous circulation was re-established in 88 (58% patients, and 42 (28% were discharged from the hospital. The necessary number of patients treated to save 1 life in 12 months was 3.4. The presence of ventricular fibrillation or tachycardia (VF/VT as the initial rhythm, shorter times of cardiopulmonary resuscitation maneuvers and cardiopulmonary arrest, and greater values of mean blood pressure (BP prior to cardiopulmonary arrest were independent variables for re-establishment of spontaneous circulation and hospital discharge. The odds ratios for hospital discharge were as follows: 6.1 (95% confidence interval [CI] = 2.7-13.6, when the initial rhythm was VF/VT; 9.4 (95% CI = 4.1-21.3, when the time of cerebral cardiopulmonary resuscitation was 70 mmHg. CONCLUSION: The presence of VF/VT as the initial rhythm, shorter times of cerebral cardiopulmonary resuscitation and of cardiopulmonary arrest, and a greater value of BP prior to cardiopulmonary arrest were independent variables of better prognosis.

  17. Attitude maneuver of liquid-filled spacecraft with a flexible appendage by momentum wheel

    Institute of Scientific and Technical Information of China (English)

    Dan-Dan Yang; Bao-Zeng Yue; Wen-Jun Wu; Xiao-Juan Song; Le-Mei Zhu

    2012-01-01

    Attitude maneuver of liquid-filled spacecraft with an appendage as a cantilever beam by momentum wheel is studied.The dynamic equations are derived by conservation of angular momentum and force equilibrium principle.A feedback control strategy of the momentum wheel is applied for the attitude maneuver.The residual nutation of the spacecraft in maneuver process changes with some chosen parameters,such as steady state time,locations of the liquid container and the appendage,and appendage parameters.The results indicate that locations in the second and fourth quadrants of the body-fixed coordinate system and the second quadrant of the wall of the main body are better choices forplacing the liquid containers and the appendage than other locations if they can be placed randomly.Higher density and thicker cross section are better for lowering the residual nutation if they can be changed.Light appendage can be modeled as a rigid body,which results in a larger residual nutation than a flexible model though.The residual nutation decreases with increasing absolute value of the initial sloshing angular height.

  18. Anatomical study of the effects of five surgical maneuvers on palate movement.

    Science.gov (United States)

    Mendonca, Derick A; Patel, Kamlesh B; Skolnick, Gary B; Woo, Albert S

    2014-06-01

    The anatomy of the palate has been extensively described, with a predominant focus on palatal musculature. There are no biomechanical studies investigating the effects of surgical maneuvers on the palate to aid cleft closure. This study aims to describe the soft tissue attachments at different zones and quantify the movement following their release. Fourteen adult cadaver heads were dissected. The palates were split in the midline and five maneuvers described: Step 1, over the hard palate; Step 2, around the greater palatine pedicle; Step 3, over the palatine aponeurosis; Step 4, over the hamulus; and Step 5, resulting in a hamulus fracture. The movements across the midline at the posterior nasal spine following each maneuver were measured. The age range of the 14 heads was between 60 -75 years. Completion of steps 1 and 2 over the hard palate obtained a mean release of 2.6 and 2.0 mm, respectively. The largest movements occurred at Step 3 (5.7 mm) and Step 4 (3.5 mm), after releasing attachments at the posterior hard palate and palatine aponeurosis. Steps 3 and 4 dissections exhibited cumulative release, with a maximum movement with Step 3 (p palate junction. Additional dissection along the hamulus (without fracture) added significantly to this release.

  19. Desaturation Maneuvers and Precise Orbit Determination for the BepiColombo Mission

    CERN Document Server

    Alessi, Elisa Maria; Milani, Andrea; Tommei, Giacomo

    2012-01-01

    The purpose of this work is the analysis of the consequences that desaturation maneuvers can have in the precise orbit determination corresponding to the Radio Science Experiment (MORE) of the BepiColombo mission to Mercury. This mission is an ESA/JAXA joint project with very challenging objectives regarding geodesy, geophysics and fundamental physics. In the neighborhood of Mercury, the s/c will experience strong solar radiation pressure torques; the s/c attitude is controlled by inertial wheels that after some time reach their maximum rotation state. Then they have to be slowed down by means of thruster pulses, inducing a residual acceleration on the s/c, with a desaturation (or off-loading) maneuver. In this paper, we will show how such maneuvers affect the orbit of the s/c and the radio science measurements and, also, how to include them in the orbit determination and parameter estimation procedure. The non linear least squares fit we consider is applied on a set of observational arcs separated by interva...

  20. Detection, parameter estimation and imaging of maneuvering target in wide-band signal

    Institute of Scientific and Technical Information of China (English)

    LI YaChao; XING MengDao; ZHANG Long; BAO Zheng

    2009-01-01

    The signal-to-noise ratio may be increased by the cross-range coherence integration so as to detect the moving target in low signal-to-noise ratio (SNR) condition. But, the radial velocity, acceleration and the change of acceleration due to the maneuvering motion of target may induce serious range migration and crose-range high-order phase terms leading to the unfocused cross-range image, the reduction of signal-noise ratio and the invalidation of target detection. Therefore, in order to solve these problems,this paper proposes a new method based on the adjacent correlation and scale transform methods for detection, parameters estimation and imaging of maneuvering targets in wide-band signal. This method can align the range and remove the cross-range high-order phase terms induced by the radial motion of target, enabling us to detect the target and estimate its moving parameters better. Finally, the simulated target is used to confirm that the method proposed by this paper can perfectly detect the maneuvering target in low signal-to-noise ratio condition, estimate its motion parameters and obtain an ISAR image of target.

  1. Dynamic Modeling and Investigation of Maneuver Characteristics of A Deep-Sea Manned Submarine Vehicle

    Institute of Scientific and Technical Information of China (English)

    XIE Jun-yuan; XU Wen-bo; ZHANG Hua; XU Peng-fei; CUI Wei-cheng

    2009-01-01

    A deep-sea Manned Submarine Vehicle (MSV) is usually required to move at a low forward speed and a low rota- tional speed when it executes investigation tasks. In this condition, the motion is in large drift angles, and the maneuver- ability hydrodynamic forces cannot be expressed properly in the conventional mathematical model of submersible motion. In this paper, firstly, a general equation of MSV with six-freedom motion is presented, and the numerical simulation of descent/ascent motion and helix motion is conducted to reveal the general maneuver characteristics of MSV. Secondly, according to the data of captive model tests of large drift angles of MSV, the regression analysis of position hydrodynamic forces and rotation hydrodynamic forces is carried out, and the resuhs of regression analysis of maneuverabihty hydrody-namic characteristics are analyzed to reveal the special maneuver characteristics. Thirdly, a special new mathematical model of MSV with the whole range of drift angles motion is presented, which can be used to predict hydrodynamic per-formance of motion in the 0°~180° range of drift angles. The resuhs are applied to the design of maneuverability hydro- dynamic forces, development of control system and simulator of a practical MSV.

  2. Coroutine Sequencing in BETA

    DEFF Research Database (Denmark)

    Kristensen, Bent Bruun; Madsen, Ole Lehrmann; Møller-Pedersen, Birger;

    In object-oriented programming, a program execution is viewed as a physical model of some real or imaginary part of the world. A language supporting object-oriented programming must therefore contain comprehensive facilities for modeling phenomena and concepts form the application domain. Many ap...... applications in the real world consist of objects carrying out sequential processes. Coroutines may be used for modeling objects that alternate between a number of sequential processes. The authors describe coroutines in BETA...

  3. Magic Baseline Beta Beam

    CERN Document Server

    Agarwalla, Sanjib Kumar; Raychaudhuri, Amitava

    2007-01-01

    We study the physics reach of an experiment where neutrinos produced in a beta-beam facility at CERN are observed in a large magnetized iron calorimeter (ICAL) at the India-based Neutrino Observatory (INO). The CERN-INO distance is close to the so-called "magic" baseline which helps evade some of the parameter degeneracies and allows for a better measurement of the neutrino mass hierarchy and $\\theta_{13}$.

  4. Beta cell adaptation in pregnancy

    DEFF Research Database (Denmark)

    Nielsen, Jens Høiriis

    2016-01-01

    Pregnancy is associated with a compensatory increase in beta cell mass. It is well established that somatolactogenic hormones contribute to the expansion both indirectly by their insulin antagonistic effects and directly by their mitogenic effects on the beta cells via receptors for prolactin...... and growth hormone expressed in rodent beta cells. However, the beta cell expansion in human pregnancy seems to occur by neogenesis of beta cells from putative progenitor cells rather than by proliferation of existing beta cells. Claes Hellerström has pioneered the research on beta cell growth for decades......, but the mechanisms involved are still not clarified. In this review the information obtained in previous studies is recapitulated together with some of the current attempts to resolve the controversy in the field: identification of the putative progenitor cells, identification of the factors involved...

  5. Regulation of beta cell replication

    DEFF Research Database (Denmark)

    Lee, Ying C; Nielsen, Jens Høiriis

    2008-01-01

    Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been...... suggested to play a role in beta cell mass regulation. In addition, genetic mouse model studies have indicated that cyclins and cyclin-dependent kinases that determine cell cycle progression are involved in beta cell replication, and more recently, menin in association with cyclin-dependent kinase...... inhibitors has been demonstrated to be important in beta cell growth. In this review, we consider and highlight some aspects of cell cycle regulation in relation to beta cell replication. The role of cell cycle regulation in beta cell replication is mostly from studies in rodent models, but whether...

  6. Maintaining Aura's Orbit Requirements While Performing Orbit Maintenance Maneuvers Containing an Orbit Normal Delta-V Component

    Science.gov (United States)

    Johnson, Megan R.; Petersen, Jeremy D.

    2014-01-01

    The Earth Observing System (EOS) Afternoon Constellation consists of five member missions (GCOM-W1, Aqua, CALIPSO, CloudSat, and Aura), each of which maintain a frozen, sun-synchronous orbit with a 16-day repeating ground track that follows the Worldwide Reference System-2 (WRS-2). Under nominal science operations for Aura, the propulsion system is oriented such that the resultant thrust vector is aligned 13.493 degrees away from the velocity vector along the yaw axis. When performing orbit maintenance maneuvers, the spacecraft performs a yaw slew to align the thrust vector in the appropriate direction. A new Drag Make Up (DMU) maneuver operations scheme has been implemented for Aura alleviating the need for the 13.493 degree yaw slew. The focus of this investigation is to assess the impact that no-slew DMU maneuver operations will have on Aura's Mean Local Time (MLT) which drives the required along track separation between Aura and the constellation members, as well as Aura's frozen orbit properties, eccentricity and argument of perigee. Seven maneuver strategies were analyzed to determine the best operational approach. A mirror pole strategy, with maneuvers alternating at the North and South poles, was implemented operationally to minimize impact to the MLT. Additional analysis determined that the mirror pole strategy could be further modified to include frozen orbit maneuvers and thus maintain both MLT and the frozen orbit properties under noslew operations.

  7. A case study of non-traditional students re-entry into college physics and engineering

    Science.gov (United States)

    Langton, Stewart Gordon

    Two groups of students in introductory physics courses of an Access Program for engineering technologies were the subjects of this study. Students with a wide range of academic histories and abilities were enrolled in the program; many of the students were re-entry and academically unprepared for post-secondary education. Five years of historical data were evaluated to use as a benchmark for revised instruction. Data were gathered to describe the pre-course academic state of the students and their academic progress during two physics courses. Additional information was used to search for factors that might constrain academic success and as feedback for the instructional methods. The data were interpreted to regulate constructivist design features for the physics courses. The Engineering Technology Access Program was introduced to meet the demand from non-traditional students for admission to two-year engineering' technology programs, but who did not meet normal academic requirements. The duration of the Access Program was two terms for electronic and computer engineering students and three terms for civil and mechanical engineering students. The sequence of mathematics and physics courses was different for the two groups. The Civil/Mechanical students enrolled in their first mathematics course before undertaking their first physics course. The first mathematics and physics courses for the Electronics students were concurrent. Academic success in the two groups was affected by this difference. Over a five-year period the success rate of students graduating with a technology diploma was approximately twenty-five percent. Results from this study indicate that it was possible to reduce the very high attrition in the combined Access/Technology Programs. While the success rate for the Electronics students increased to 38% the rate for the Civil/Mechanical students increased dramatically to 77%. It is likely that several factors, related to the extra term in the Access

  8. Visualization of Capsule Reentry Vehicle Heat Shield Ablation Using Naphthalene PLIF

    Science.gov (United States)

    Combs, Christopher S.; Clemens, Noel T.; Danehy, Paul M.

    2014-01-01

    The Orion Multi-Purpose Crew Vehicle (MPCV) will use an ablative heat shield and improved understanding of the ablation process would be beneficial for design purposes. Given that ablation is a multi-physics process involving heat and mass transfer, codes aiming to predict heat shield ablation are in need of experimental data pertaining to the turbulent transport of ablation products for validation. At The University of Texas at Austin, a technique is being developed that uses planar laser-induced fluorescence (PLIF) of a low-temperature sublimating ablator (naphthalene) to visualize the transport of ablation products in a supersonic flow. Since ablation at reentry temperatures can be difficult to recreate in a laboratory setting it is desirable to create a limited physics problem and simulate the ablation process at relatively low temperature conditions using naphthalene. A scaled Orion MPCV model with a solid naphthalene heat shield has been tested in a Mach 5 wind tunnel at various angles of attack in the current work. PLIF imaging reveals the distribution of the ablation products as they are transported into the heat-shield boundary layer and over the capsule shoulders into the separated shear layer and backshell recirculation region. Visualizations of the capsule shear layer using both naphthalene PLIF and Schlieren imaging compared favorably. High concentrations of naphthalene in the capsule separated flow region, intermittent turbulent structures on the heat shield surface, and interesting details of the capsule shear layer structure were observed using the naphthalene PLIF technique. The capsule shear layer was also shown to generally appear to be more turbulent at lower angles of attack. Furthermore, the PLIF signal increased steadily over the course of a run indicating that during a wind tunnel run the model heated up and the rate of naphthalene ablation increased. The shear layer showed increasing signs of turbulence over the course of a wind tunnel run

  9. Processing Near-Infrared Imagery of the Orion Heatshield During EFT-1 Hypersonic Reentry

    Science.gov (United States)

    Spisz, Thomas S.; Taylor, Jeff C.; Gibson, David M.; Kennerly, Steve; Osei-Wusu, Kwame; Horvath, Thomas J.; Schwartz, Richard J.; Tack, Steven; Bush, Brett C.; Oliver, A. Brandon

    2016-01-01

    The Scientifically Calibrated In-Flight Imagery (SCIFLI) team captured high-resolution, calibrated, near-infrared imagery of the Orion capsule during atmospheric reentry of the EFT-1 mission. A US Navy NP-3D aircraft equipped with a multi-band optical sensor package, referred to as Cast Glance, acquired imagery of the Orion capsule's heatshield during a period when Orion was slowing from approximately Mach 10 to Mach 7. The line-of-sight distance ranged from approximately 65 to 40 nmi. Global surface temperatures of the capsule's thermal heatshield derived from the near-infrared intensity measurements complemented the in-depth (embedded) thermocouple measurements. Moreover, these derived surface temperatures are essential to the assessment of the thermocouples' reliance on inverse heat transfer methods and material response codes to infer the surface temperature from the in-depth measurements. The paper describes the image processing challenges associated with a manually-tracked, high-angular rate air-to-air observation. Issues included management of significant frame-to-frame motions due to both tracking jerk and jitter as well as distortions due to atmospheric effects. Corrections for changing sky backgrounds (including some cirrus clouds), atmospheric attenuation, and target orientations and ranges also had to be made. The image processing goal is to reduce the detrimental effects due to motion (both sensor and capsule), vibration (jitter), and atmospherics for image quality improvement, without compromising the quantitative integrity of the data, especially local intensity (temperature) variations. The paper will detail the approach of selecting and utilizing only the highest quality images, registering several co-temporal image frames to a single image frame to the extent frame-to-frame distortions would allow, and then co-adding the registered frames to improve image quality and reduce noise. Using preflight calibration data, the registered and averaged

  10. LHCb: $2\\beta_s$ measurement at LHCb

    CERN Multimedia

    Conti, G

    2009-01-01

    A measurement of $2\\beta_s$, the phase of the $B_s-\\bar{B_s}$ oscillation amplitude with respect to that of the ${\\rm b} \\rightarrow {\\rm c^{+}}{\\rm W^{-}}$ tree decay amplitude, is one of the key goals of the LHCb experiment with first data. In the Standard Model (SM), $2\\beta_s$ is predicted to be $0.0360^{+0.0020}_{-0.0016} \\rm rad$. The current constraints from the Tevatron are: $2\\beta_{s}\\in[0.32 ; 2.82]$ at 68$\\%$CL from the CDF experiment and $2\\beta_{s}=0.57^{+0.24}_{-0.30}$ from the D$\\oslash$ experiment. Although the statistical uncertainties are large, these results hint at the possible contribution of New Physics in the $B_s-\\bar{B_s}$ box diagram. After one year of data taking at LHCb at an average luminosity of $\\mathcal{L}\\sim2\\cdot10^{32}\\rm cm^{-2} \\rm s^{-1}$ (integrated luminosity $\\mathcal{L}_{\\rm int}\\sim 2 \\rm fb^{-1}$), the expected statistical uncertainty on the measurement is $\\sigma(2\\beta_s)\\simeq 0.03$. This uncertainty is similar to the $2\\beta_s$ value predicted by the SM.

  11. Re-entry communication through a plasma sheath using standing wave detection and adaptive data rate control

    Science.gov (United States)

    Xie, Kai; Yang, Min; Bai, Bowen; Li, Xiaoping; Zhou, Hui; Guo, Lixin

    2016-01-01

    Radio blackout during the re-entry has puzzled the aerospace industry for decades and has not yet been completely resolved. To achieve a continuous data link in the spacecraft's re-entry period, a simple and practicable communication method is proposed on the basis that (1) the electromagnetic-wave backscatter of the plasma sheath affects the voltage standing wave ratio (VSWR) of the antenna, and the backscatter is negatively correlated to transmission components, and (2) the transmission attenuation caused by the plasma sheath reduces the channel capacity. We detect the voltage standing wave ratio changes of the antenna and then adjust the information rate to accommodate the varying channel capacity, thus guaranteeing continuous transmission (for fewer critical data). The experiment was carried out in a plasma generator with an 18-cm-thick and 30-cm-diameter hollow propagation path, and the adaptive communication was implemented using spread spectrum frequency, shift key modulation with a variable spreading factor. The experimental results indicate that, when the over-threshold of VSWR was detected, the bit rate reduced to 250 bps from 4 Mbps automatically and the tolerated plasma density increased by an order of magnitude, which validates the proposed scheme. The proposed method has little additional cost, and the adaptive control does not require a feedback channel. The method is therefore applicable to data transmission in a single direction, such as that of a one-way telemetry system.

  12. An electromagnetic method for removing the communication blackout with a space vehicle upon re-entry into the atmosphere

    Science.gov (United States)

    Cheng, Jianjun; Jin, Ke; Kou, Yong; Hu, Ruifeng; Zheng, Xiaojing

    2017-03-01

    When a hypersonic vehicle travels in the Earth and Mars atmosphere, the surface of the vehicle is surrounded by a plasma layer, which is an envelope of ionized air, created from the compression and heat of the atmosphere by the shock wave. The vehicles will lose contact with ground stations known as the reentry communication blackout. Based on the magnetohydrodynamic framework and electromagnetic wave propagation theory, an analytical model is proposed to describe the effect of the effectiveness of electromagnetic mitigation scheme on removing the reentry communication blackout. C and Global Positioning System (GPS) bands, two commonly used radio bands for communication, are taken as the cases to discuss the effectiveness of the electromagnetic field mitigation scheme. The results show that the electron density near the antenna of vehicles can be reduced by the electromagnetic field, and the required external magnetic field strength is far below the one in the magnetic window method. The directions of the external electric field and magnetic field have a significant impact on the effectiveness of the mitigation scheme. Furthermore, the effect of electron collisions on the required applied electromagnetic field is discussed, and the result indicates that electron collisions are a key factor to analyze the electromagnetic mitigation scheme. Finally, the feasible regions of the applied electromagnetic field for eliminating blackout are given. These investigations could have a significant benefit on the design and optimization of electromagnetic mitigation scheme for the blackout problem.

  13. Evaluation of the Positive Re-Entry in Corrections Program: A Positive Psychology Intervention With Prison Inmates.

    Science.gov (United States)

    Huynh, Kim H; Hall, Brittany; Hurst, Mark A; Bikos, Lynette H

    2015-08-01

    Two groups of male inmates (n = 31, n = 31) participated in the Positive Re-Entry in Corrections Program (PRCP). This positive psychology intervention focused on teaching offenders skills that facilitate re-entry into the community. Offenders participated in weekly lectures, discussions, and homework assignments focused on positive psychology principles. The two groups differed in duration of treatment (8 weeks and 12 weeks). Participants completed pre- and post-intervention measures of gratitude, hope, and life satisfaction. Using a 2 × 2 mixed design ANOVA, we hypothesized that the intervention (with two between-subjects levels of 8 and 12 weeks) and duration (with two repeated measures levels of pre and post) of treatment would moderate pre- to post-intervention change. Results indicated significant differences on pre- and post-intervention scores for both groups of offenders on all measures. The analysis did not yield statistically significant differences between groups, demonstrating no additive benefits from the inclusion of four additional sessions, thus saving time and money for correctional programming and funding. This research supports the use of positive psychology in prison interventions.

  14. Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful.

    Science.gov (United States)

    Ryana, Haneet Kour; Srinath, Rashmi; Prakash, Shobha

    2016-06-01

    Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes.

  15. Finite-time sliding mode attitude control for a reentry vehicle with blended aerodynamic surfaces and a reaction control system

    Institute of Scientific and Technical Information of China (English)

    Geng Jie; Sheng Yongzhi; Liu Xiangdong

    2014-01-01

    This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction control system (RCS). Firstly, a novel finite-time attitude controller is pointed out with the introduction of a nonsingular finite-time sliding mode manifold. The attitude tracking errors are mathematically proved to converge to zero within finite time which can be estimated. In order to improve the performance, a second-order finite-time slid-ing mode controller is further developed to effectively alleviate chattering without any deterioration of robustness and accuracy. Moreover, an optimization control allocation algorithm, using linear programming and a pulse-width pulse-frequency (PWPF) modulator, is designed to allocate torque commands for all the aerodynamic surface deflections and on-off switching-states of RCS thrusters. Simulations are provided for the reentry vehicle considering uncertain parameters and external disturbances for practical purposes, and the results demonstrate the effectiveness and robustness of the attitude control system.

  16. Is the time dimension of the cell cycle re-entry in AD regulated by centromere cohesion dynamics?

    Science.gov (United States)

    Bajić, Vladan P; Spremo-Potparević, Biljana; Zivković, Lada; Djelić, Ninoslav; Smith, Mark A

    2008-01-01

    Chromosomal involvement is a legitimate, yet not well understood, feature of Alzheimer disease (AD). Firstly, AD affects more women than men. Secondly, the amyloid-β protein precursor genetic mutations, responsible for a cohort of familial AD cases, reside on chromosome 21, the same chromosome responsible for the developmental disorder Down's syndrome. Thirdly, lymphocytes from AD patients display a novel chromosomal phenotype, namely premature centromere separation (PCS). Other documented morphological phenomena associated with AD include the occurrence of micronuclei, aneuploidy, binucleation, telomere instability, and cell cycle re-entry protein expression. Based on these events, here we present a novel hypothesis that the time dimension of cell cycle re-entry in AD is highly regulated by centromere cohesion dynamics. In view of the fact that neurons can re-enter the cell division cycle, our hypothesis predicts that alterations in the signaling pathway leading to premature cell death in neurons is a consequence of altered regulation of the separation of centromeres as a function of time. It is well known that centromeres in the metaphase-anaphase transition separate in a non-random, sequential order. This sequence has been shown to be deregulated in aging cells, various tumors, syndromes of chromosome instability, following certain chemical inductions, as well as in AD. Over time, premature chromosome separation is both a result of, and a driving force behind, further cohesion impairment, activation of cyclin dependent kinases, and mitotic catastrophe, a vicious circle resulting in cellular degeneration and death.

  17. Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful

    Science.gov (United States)

    Srinath, Rashmi; Prakash, Shobha

    2016-01-01

    Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes. PMID:27504421

  18. An evaluation of a resorbable (semirigid GTR membrane in human periodontal intraosseous defects: A clinicoradiological re-entry study

    Directory of Open Access Journals (Sweden)

    Vinayak S Gowda

    2011-01-01

    Full Text Available Aim: To evaluate the effectiveness of a resorbable, semi rigid guided tissue regeneration (GTR membrane in the treatment of periodontal intraosseous defects. Settings and Design: Randomized controlled clinicoradiological re-entry study. Materials and Methods: Eight patients with bilateral, identical intraosseous defects were selected. The sides for test and control group were randomly allocated to treat either with bioresorbable semi rigid membrane (test group or open flap debridement (control group. Radiographic analysis was done by comparing intraoral peri apical radiographs taken at baseline and at six months. Extended cone paralleling device with grid was used to standardize radiographs. Auto CAD software was used for the analysis. Statistical Analysis Used: Paired-t test. Results: On surgical reentry at six months, the mean reduction in depth of the defect at the test site was 2.63 mm. The mean gain in Relative attachment level was 1.75 mm. The control sites showed a statistically insignificant gain. The mean percentage defect fill assessed on radiographs using auto CAD software was 15.54%. Conclusion: The resorbable, semi-rigid GTR membrane can be effectively used for the treatment of human one-walled angular defects.

  19. Review of six cases of maxillary ameloblastoma from the West Indies: re-entry cryosurgery as prophylactic surgical intervention.

    Science.gov (United States)

    Ogunsalu, C; Scipio, E; Williams, N

    2009-09-01

    Maxillary ameloblastoma is a rare histopathological entity. A total of six cases of histologically confirmed maxillary ameloblastoma from the West Indies is reviewed. Three of the cases were taken from a total of 47 histologically confirmed ameloblastoma over a 15-year period (1980-1995) from two major maxillofacial units in Jamaica. Two other cases were from documentation in Jamaica between 2000 and 2002, one of which occurred in a 13-year-old girl (these two patients have been followed-up periodically to 2006). The sixth case was from the records of the maxillofacial department of the University of the West Indies in Trinidad and Tobago. This last patient, at a recent review, has inoperable recurrence. These cases were reviewed with respect to demographics (patient's age and gender), location and extent of tumour, radiological features, concurrent involvement of the mandible, treatment with special emphasis on current treatment modality and follow-up. The findings do not differ from what has been documented by other authors from other parts of the world. Because of the radiographic anatomy of the maxilla, recurrence may be detected late despite such occurring earlier following initial surgical management. It is for this reason that we suggest re-entry cryosurgery for prevention of recurrence for maxillary ameloblastoma. The only case of maxillary ameloblastoma that had re-entry cryosurgery continues to benefit from absence of recurrence at periodic follow-ups at four years post-primary surgical management (which was enucleation).

  20. Uncertainty Requirement Analysis for the Orbit, Attitude, and Burn Performance of the 1st Lunar Orbit Insertion Maneuver

    Science.gov (United States)

    Song, Young-Joo; Bae, Jonghee; Kim, Young-Rok; Kim, Bang-Yeop

    2016-12-01

    In this study, the uncertainty requirements for orbit, attitude, and burn performance were estimated and analyzed for the execution of the 1st lunar orbit insertion (LOI) maneuver of the Korea Pathfinder Lunar Orbiter (KPLO) mission. During the early design phase of the system, associate analysis is an essential design factor as the 1st LOI maneuver is the largest burn that utilizes the onboard propulsion system; the success of the lunar capture is directly affected by the performance achieved. For the analysis, the spacecraft is assumed to have already approached the periselene with a hyperbolic arrival trajectory around the moon. In addition, diverse arrival conditions and mission constraints were considered, such as varying periselene approach velocity, altitude, and orbital period of the capture orbit after execution of the 1st LOI maneuver. The current analysis assumed an impulsive LOI maneuver, and two-body equations of motion were adapted to simplify the problem for a preliminary analysis. Monte Carlo simulations were performed for the statistical analysis to analyze diverse uncertainties that might arise at the moment when the maneuver is executed. As a result, three major requirements were analyzed and estimated for the early design phase. First, the minimum requirements were estimated for the burn performance to be captured around the moon. Second, the requirements for orbit, attitude, and maneuver burn performances were simultaneously estimated and analyzed to maintain the 1st elliptical orbit achieved around the moon within the specified orbital period. Finally, the dispersion requirements on the B-plane aiming at target points to meet the target insertion goal were analyzed and can be utilized as reference target guidelines for a mid-course correction (MCC) maneuver during the transfer. More detailed system requirements for the KPLO mission, particularly for the spacecraft bus itself and for the flight dynamics subsystem at the ground control center