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1

Optical Survey of the Tumble Rates of Retired GEO Satellites  

NASA Astrophysics Data System (ADS)

The Naval Research Lab (NRL) and the Defense Advanced Research Projects Agency (DARPA) have made significant progress toward robotic rendezvous and docking between spacecraft, however the long-term attitude motion evolution of uncontrolled resident space objects has never been well-characterized. This effort set out to identify the motion exhibited in retired satellites at or near geosynchronous orbit (GEO). Through analysis of the periodic structure of observed reflected light curves, estimated tumble rates were determined for several retired satellites, typically in a super-GEO disposal orbit. The NRL's 1-meter telescope at Midway Research Center was used to track and observe the objects while the sun-satellite-observer geometry was most favorable; typically over a one- to two-hour period, repeated multiple times over the course of weeks. By processing each image with calibration exposures, the relative apparent magnitude of the brightness of the object over time was determined. Several tools, including software developed internally, were used for frequency analysis of the brightness curves. Results show that observed satellites generally exhibit a tumble rate well below the notional bounding case of one degree per second. When harmonics are found to exist in the data, modeling and simulation of the optical characteristics of the satellite can help to resolve ambiguities. This process was validated on spacecraft for which an attitude history is known, and agreement was found.

Binz, C.; Davis, M.; Kelm, B.; Moore, C.

2014-09-01

2

A modified proportional navigation scheme for rendezvous and docking with tumbling targets: The Planar case  

NASA Technical Reports Server (NTRS)

A two-phase proportional navigation scheme is developed for the case of two rigid bodies engaged in a rendezvous/docking maneuver. The target vehicle is nonmaneuvering, but does have constant nonzero angular and linear velocities. Under these conditions, it is shown that previously obtained solutions are not applicable. Analytical solutions are obtained leading to relationships between the transverse and LOS navigation constants. It is shown that the transverse navigation constant for the second phase of the maneuver must be 2. Also, initial conditions necessary for rendezvous are presented.

Fitz-Coy, Norman; Liu, Ming-Cheng

1995-01-01

3

Study of effects of uncertainties of comet and asteroid encounter and contact guidance requirements. Part 2: Tumbling problem studies. [development of navigation and guidance techniques for space rendezvous  

NASA Technical Reports Server (NTRS)

The problem of determining the rotational motion of a tumbling celestial body of the asteroid type using spacecraft-acquired data is addressed. The rotational motion of the body is modeled by free-Eulerian motion of a triaxial, rigid body and its translational motion with respect, to a nonrotating, observing spacecraft, which is not thrusting, is assumed to be uniform during the time observations are made. The mathematical details which form the basis for a digital simulation of the motion and observations are presented. Two algorithms for determining the motion from observations for the special case of uniform rotational motion are given.

Cochran, J. E., Jr.

1974-01-01

4

Tumbling cards  

NASA Astrophysics Data System (ADS)

When a stiff rectangular card is dropped in still air with its long axis horizontal, it often settles into a regular mode of motion; while revolving around its long axis it descends along a path that is inclined to the vertical at a nearly constant angle. We show experimentally that the tumbling frequency ? of a card of length l, width w and thickness d (l?w?d) scales as ?˜d1/2w-1, consistent with a simple dimensional argument that balances the drag against gravity.

Mahadevan, L.; Ryu, William S.; Samuel, Aravinthan D. T.

1999-01-01

5

Rendezvous effects in the diffusion process on bipartite metapopulation networks  

NASA Astrophysics Data System (ADS)

Epidemic outbreaks have been shown to be closely related to the rendezvous-induced transmission of infection, which is caused by casual contact with infected individuals in public gatherings. To investigate rendezvous effects in the spread of infectious diseases, we propose an epidemic model on metapopulation networks bipartite-divided into two sets of location and rendezvous nodes. At a given transition rate ?kk'p, each individual transfers from location k to rendezvous p (where rendezvous-induced disease incidence occurs) and thereafter moves to location k'. We find that the eigenstructure of a transition-rate-dependent matrix determines the epidemic threshold condition. Both analytical and numerical results show that rendezvous-induced transmission accelerates the progress of infectious diseases, implying the significance of outbreak control measures including prevention of public gatherings or decentralization of a large-scale rendezvous into downsized ones.

Cao, Lang; Li, Xun; Wang, Bing; Aihara, Kazuyuki

2011-10-01

6

Parametric study of predictor accuracy impact on OFT rendezvous targeting  

NASA Technical Reports Server (NTRS)

A parametric study was made to quantitatively define the effects of errors in the state vector predictor used by the Operational Flight Trainer (OFT) rendezvous targeting algorithms. The effect of the predictor accuracy on the OFT rendezvous profile is shown by the sensitivity of various critical rendezvous parameters with respect to downrange and radial predictor error rates. The effect of both inertial (same errors on both vehicles) and relative (differential errors on one vehicle with respect to the other) errors were considered. Relative radial error rates had the largest impact on the rendezvous followed by relative downrange errors, radial inertial errors and downrange inertial errors.

Glenn, S. W.

1976-01-01

7

QUENCHING TUMBLING MILL TUMBLES CASTINGS OVER EACH OTHER TO REMOVE ...  

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

QUENCHING TUMBLING MILL TUMBLES CASTINGS OVER EACH OTHER TO REMOVE RUNNERS AND SPRUES WHILE QUICKLY COOLING THEM WITH WATER IN THE MALLEABLE ANNEALING BUILDING. THIS PROCESS ENSURES CASTINGS FORM WHITE IRON PRIOR TO BEING ASSEMBLED. - Stockham Pipe & Fittings Company, Malleable Annealing Building, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

8

Automated orbital rendezvous considerations  

NASA Technical Reports Server (NTRS)

The control of the rendezvous vehicle during proximity operations is considered. It is shown how fuzzy sets can be used for autonomous vehicle control to model the human capability of common sense reasoning. Such models are integrated with expert systems and engineering control systems technology to create a system that performs comparably to a manned system.

Lea, Robert N.

1988-01-01

9

Effect of geometry, static stability, and mass distribution on the tumbling characteristics of generic flying-wing models  

NASA Technical Reports Server (NTRS)

Results from an investigation to determine the low-speed tumbling characteristics of twelve generic flying-wing models are summarized. There is a concern that airplanes with flying-wing planforms could inadvertently enter an out-of-control tumbling motion under certain conditions. The objectives of this investigation were to: 1) identify the geometric and mass-related parameters that cause flying wings to be capable of sustained tumbling, 2) analyze some of the driving mechanisms that cause tumbling, and 3) determine the feasibility of using computer simulations to predict the tumbling characteristics of flying wings. Free-tumble and free-to-pitch tests were conducted with dynamically-scaled, generic flying wing models. The use of computer simulations as a predictive tool for tumbling was explored. Results indicated that center-of-gravity location, mass distribution, and geometric aspect ratio strongly affected the tumbling characteristics of the models tested and that positive static stability did not necessarily preclude tumbling. The magnitude of dynamic effects were found to be of the same order as static effects for the models undergoing autorotation-in-pitch. The simulations indicated that the dynamic terms in the equations of motion used to predict tumbling must be obtained using experimental methods that account for the large amplitude/high pitch-rate environment that characterizes tumbling.

Fremaux, C. M.; Vairo, D. M.; Whipple, R. D.

1993-01-01

10

Cooperative control of UAV rendezvous  

Microsoft Academic Search

The cooperative control of timing and synchronization of tasks of multiple unmanned air vehicles (UAVs) represents a valuable capability for a wide range of potential multi-UAV missions. This research addresses the specific problem of cooperative rendezvous in which multiple UAVs are to arrive at their targets simultaneously. The development of a rendezvous manager state machine and a cooperative control decomposition

T. W. McLain; Phillip R. Chandler; Steven Rasmussen; Meir Pachter

2001-01-01

11

2705 Wu: A Tumbling Asteroid  

NASA Astrophysics Data System (ADS)

2705 Wu was observed in 2009 July through September. The initial results showed a lightcurve with synodic period of 150.5h ± 0.5h. The observations were also checked for variations seen in the mean lightcurve. After eliminating other causes of the variations, it was concluded that 2705 Wu exhibited Non-Principal Axis (NPA) rotation, or tumbling behavior. Attempts to derive the secondary period were unsuccessful.

Oey, Julian

2010-04-01

12

Multiple asteroid rendezvous missions  

NASA Technical Reports Server (NTRS)

Asteroid missions, centered on multiple asteroid rendezvous missions to main belt asteroids, are discussed and the required solar electric propulsion for these missions as well as the current performance estimates are examined. A brief statistical analysis involving asteroid availability transfer requirements and propulsion system capabilities is given, leading to a prediction that 5 to 8 asteroids can be encountered with a single launch. Measurement techniques include visual imaging, radio tracking, magnetometry, and in the case of landers, seismometry. The spacecraft will be propelled by a solar electric system with a power level of 25 kW to 40 kW and tour possibilities for 13 different asteroids have been developed. Preliminary estimates of asteroid triaxiality are made to calculate the effect of close orbits.

Bender, D. F.; Friedlander, A. L.

1979-01-01

13

The tumbling spin state of (99942) Apophis  

NASA Astrophysics Data System (ADS)

Our photometric observations of Asteroid (99942) Apophis from December 2012 to April 2013 revealed it to be in a state of non-principal axis rotation (tumbling). We constructed its spin and shape model and found that it is in a moderately excited Short Axis Mode (SAM) state with a ratio of the rotational kinetic energy to the basic spin state energy E/E0=1.024±0.013. (All quoted uncertainties correspond to 3?.) The greatest and intermediate principal moments of inertia are nearly the same with I2/I3=0.965-0.015+0.009, but the smallest principal moment of inertia is substantially lower with I1/I3=0.61-0.08+0.11; the asteroid’s dynamically equivalent ellipsoid is close to a prolate ellipsoid. The precession and rotation periods are P?=27.38±0.07 h and P?=263±6 h, respectively; the strongest observed lightcurve amplitude for the SAM case is in the 2nd harmonic of P1=P=30.56±0.01 h. The rotation is retrograde with the angular momentum vector’s ecliptic longitude and latitude of 250° and -75° (the uncertainty area is approximately an ellipse with the major and minor semiaxes of 27° and 14°, respectively). An implication of the retrograde rotation is a somewhat increased probability of the Apophis’ impact in 2068, but it is still very small with the risk level on the Palermo Scale remaining well below zero. Apophis is a member of the population of slowly tumbling asteroids. Applying the theory of asteroid nutational damping by Breiter et al. (Breiter, S., Ro?ek, A., Vokrouhlický, D. [2012]. Mon. Not. R. Astron. Soc. 427, 755-769), we found that slowly tumbling asteroids predominate in the spin rate-size range where their estimated damping times are greater than about 0.2 Gyr. The appearance that the PA/NPA rotators transition line seems to follow a line of constant damping time may be because there are two or more asteroid spin evolution mechanisms in play, or the factor of ?Q (the elastic modulus times the quality factor) is not constant but it may decrease with decreasing asteroid size, which would oppose the trend due to decreasing collisional age or excitation time.

Pravec, P.; Scheirich, P.; ?urech, J.; Pollock, J.; Kušnirák, P.; Hornoch, K.; Galád, A.; Vokrouhlický, D.; Harris, A. W.; Jehin, E.; Manfroid, J.; Opitom, C.; Gillon, M.; Colas, F.; Oey, J.; Vraštil, J.; Reichart, D.; Ivarsen, K.; Haislip, J.; LaCluyze, A.

2014-05-01

14

An extension of generalized Taylor dispersion in unbounded homogeneous shear flows to run-and-tumble chemotactic bacteria  

E-print Network

-and-tumble chemotactic bacteria R. N. Bearon School of Oceanography, Box 357940, University of Washington, Seattle of flow, the biased random walk of bacteria such as Escherichia coli is modeled by straight runs. In the well-studied situation of weak bias in tumble rate, bacteria disperse over a diffusive time scale

Bearon, Rachel

15

Photometric Analysis of the Very Long Period and Tumbling Asteroid 1278 Kenya  

NASA Astrophysics Data System (ADS)

1278 Kenya is a long period main-belt asteroid. It was observed in collaboration among four photometrists located over two months at widely spaced locations. This asteroid is in non-principal axis (NPA) rotation, also known as tumbling. The primary period was determined to be 188 ± 1 h with a candidate second period of 127 ± 1 h. The quality of the tumbling solution is rated as PAR= ˜2, tending to ˜3.

Oey, Julian; Pilcher, Frederick; Benishek, Vladimir; Higgins, David; Pravec, Petr

2012-04-01

16

Automated rendezvous and docking with video imagery  

NASA Technical Reports Server (NTRS)

For rendezvous and docking, assessing and tracking relative orientation is necessary within a minimum approach distance. Special target light patterns have previously been considered for use with video sensors for ease of determining relative orientation. A generalization of those approaches is addressed. At certain ranges, the entire structure of the target vehicle constitutes an acceptable target; at closer ranges, substructures will suffice. Acting on the same principle as the human intelligence, these structures can be compared with a memory model to assess the relative orientation and range. Models for comparison are constructed from a CAD facet model and current imagery. This approach requires fast image handling, projection, and comparison techniques which rely on rapidly developing parallel processing technology. Relative orientation and range assessment consists of successful comparison of the perceived target aspect with a known aspect. Generating a known projection from a model within required times, say subsecond times, is only now approaching feasibility. With this capability, rates of comparison used by the human brain can be approached and arbitrary known structures can be compared in reasonable times. Future space programs will have access to powerful computation devices which far exceed even this capability. For example, the possibility will exist to assess unknown structures and then control rendezvous and docking, all at very fast rates. The first step which has the current utility, namely applying this to known structures, is taken.

Rodgers, Mike; Kennedy, Larry Z.

1991-01-01

17

Automated rendezvous and docking with video imagery  

NASA Astrophysics Data System (ADS)

For rendezvous and docking, assessing and tracking relative orientation is necessary within a minimum approach distance. Special target light patterns have previously been considered for use with video sensors for ease of determining relative orientation. A generalization of those approaches is addressed. At certain ranges, the entire structure of the target vehicle constitutes an acceptable target; at closer ranges, substructures will suffice. Acting on the same principle as the human intelligence, these structures can be compared with a memory model to assess the relative orientation and range. Models for comparison are constructed from a CAD facet model and current imagery. This approach requires fast image handling, projection, and comparison techniques which rely on rapidly developing parallel processing technology. Relative orientation and range assessment consists of successful comparison of the perceived target aspect with a known aspect. Generating a known projection from a model within required times, say subsecond times, is only now approaching feasibility. With this capability, rates of comparison used by the human brain can be approached and arbitrary known structures can be compared in reasonable times. Future space programs will have access to powerful computation devices which far exceed even this capability. For example, the possibility will exist to assess unknown structures and then control rendezvous and docking, all at very fast rates. The first step which has the current utility, namely applying this to known structures, is taken.

Rodgers, Mike; Kennedy, Larry Z.

18

Karst Conservation in the Ozarks: Forty Years at Tumbling  

Microsoft Academic Search

In this paper we detail nearly 40 years of scientific work and land manage - ment in and around Tumbling Creek Cave, Missouri. Tumbling Creek Cave is a famous educational and research cave on a rural property called the \\

Creek Cave; William R. Elliott; Thomas J. Aley

19

STS-134 Re-Rendezvous Design History  

NASA Technical Reports Server (NTRS)

In preparation to provide the capability for the Orion spacecraft to rendezvous with the International Space Station (ISS), a new suite of relative navigation sensors are in development and will be tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the instruments on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle Orbiter at the end of the mission. Unlike the initial rendezvous and docking, the re-rendezvous profile would replicate the newly designed Orion coelliptic approach trajectory, something never before attempted with the Shuttle Orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this re-rendezvous to make the flight test successful. And all of this work had to be integrated with the normal operations of the ISS and Shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and re-rendezvous trajectory design that will prove not only the design of the relative navigation sensors for the Orion vehicle, but also will serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

Stuit, Timothy D.

2011-01-01

20

Elementary School Children's Rough-and-Tumble Play.  

ERIC Educational Resources Information Center

The purposes of this study were to describe elementary school children's rough-and-tumble play vis-a-vis aggression and provide exploratory data on the functional significance of rough-and-tumble play. Results suggest that the incidence of rough-and-tumble play varied according to sex and playground location. (PCB)

Pellegrini, A. D.

1989-01-01

21

Observing Young Children's Rough-and-Tumble Play  

ERIC Educational Resources Information Center

This research investigated the rough-and-tumble play of 17 five-year-old children in two early childhood settings. The study resulted in an increased understanding of the forms of rough-and-tumble play displayed by young children. This study demonstrates that both boys and girls are engaged in a variety of rough-and-tumble play behaviours.…

Tannock, Michelle

2011-01-01

22

NASA MSFC hardware in the loop simulations of automatic rendezvous and capture systems  

NASA Technical Reports Server (NTRS)

Two complementary hardware-in-the-loop simulation facilities for automatic rendezvous and capture systems at MSFC are described. One, the Flight Robotics Laboratory, uses an 8 DOF overhead manipulator with a work volume of 160 by 40 by 23 feet to evaluate automatic rendezvous algorithms and range/rate sensing systems. The other, the Space Station/Station Operations Mechanism Test Bed, uses a 6 DOF hydraulic table to perform docking and berthing dynamics simulations.

Tobbe, Patrick A.; Naumann, Charles B.; Sutton, William; Bryan, Thomas C.

1991-01-01

23

Hubble Space Telescope Servicing Mission 3A Rendezvous Operations  

NASA Technical Reports Server (NTRS)

The Hubble Space Telescope (HST) hardware complement includes six gas bearing, pulse rebalanced rate integrating gyros, any three of which are sufficient to conduct the science mission. After the loss of three gyros between April 1997 and April 1999 due to a known corrosion mechanism, NASA decided to split the third HST servicing mission into SM3A, accelerated to October 1999, and SM3B, scheduled for November 2001. SM3A was developed as a quick turnaround 'Launch on Need' mission to replace all six gyros. Loss of a fourth gyro in November 1999 caused HST to enter Zero Gyro Sunpoint (ZGSP) safemode, which uses sun sensors and magnetometers for attitude determination and momentum bias to maintain attitude stability during orbit night. Several instances of large attitude excursions during orbit night were observed, but ZGSP performance was adequate to provide power-positive sun pointing and to support low gain antenna communications. Body rates in ZGSP were estimated to exceed the nominal 0.1 deg/sec rendezvous limit, so rendezvous operations were restructured to utilize coarse, limited life, Retrieval Mode Gyros (RMGs) under Hardware Sunpoint (HWSP) safemode. Contingency procedures were developed to conduct the rendezvous in ZGSP in the event of RMGA or HWSP computer failure. Space Shuttle Mission STS-103 launched on December 19, 1999 after a series of weather and Shuttle-related delays. After successful rendezvous and grapple under HWSP/RMGA, the crew changed out all six gyros. Following deploy and systems checkout, HST returned to full science operations.

Lee, S.; Anandakrishnan, S.; Connor, C.; Moy, E.; Smith, D.; Myslinski, M.; Markley, L.; Vernacchio, A.

2001-01-01

24

Unsteady aerodynamics of fluttering and tumbling plates  

NASA Astrophysics Data System (ADS)

We investigate the aerodynamics of freely falling plates in a quasi-two-dimensional flow at Reynolds number of 10(3) , which is typical for a leaf or business card falling in air. We quantify the trajectories experimentally using high-speed digital video at sufficient resolution to determine the instantaneous plate accelerations and thus to deduce the instantaneous fluid forces. We compare the measurements with direct numerical solutions of the two-dimensional Navier Stokes equation. Using inviscid theory as a guide, we decompose the fluid forces into contributions due to acceleration, translation, and rotation of the plate. For both fluttering and tumbling we find that the fluid circulation is dominated by a rotational term proportional to the angular velocity of the plate, as opposed to the translational velocity for a glider with fixed angle of attack. We find that the torque on a freely falling plate is small, i.e. the torque is one to two orders of magnitude smaller than the torque on a glider with fixed angle of attack. Based on these results we revise the existing ODE models of freely falling plates. We get access to different kinds of dynamics by exploring the phase diagram spanned by the Reynolds number, the dimensionless moment of inertia, and the thickness-to-width ratio. In agreement with previous experiments, we find fluttering, tumbling, and apparently chaotic motion. We further investigate the dependence on initial conditions and find brief transients followed by periodic fluttering described by simple harmonics and tumbling with a pronounced period-two structure. Near the cusp-like turning points, the plates elevate, a feature which would be absent if the lift depended on the translational velocity alone.

Andersen, A.; Pesavento, U.; Wang, Z. Jane

2005-10-01

25

The Rendezvous Monitoring Display Capabilities of the Rendezvous and Proximity Operations Program  

NASA Technical Reports Server (NTRS)

The Rendezvous and Proximity Operations Program (RPOP) is a laptop computer- based relative navigation tool and piloting aid that was developed during the Space Shuttle program. RPOP displays a graphical representation of the relative motion between the target and chaser vehicles in a rendezvous, proximity operations and capture scenario. After being used in over 60 Shuttle rendezvous missions, some of the RPOP display concepts have become recognized as a minimum standard for cockpit displays for monitoring the rendezvous task. To support International Space Station (ISS) based crews in monitoring incoming visiting vehicles, RPOP has been modified to allow crews to compare the Cygnus visiting vehicle s onboard navigated state to processed range measurements from an ISS-based, crew-operated Hand Held Lidar sensor. This paper will discuss the display concepts of RPOP that have proven useful in performing and monitoring rendezvous and proximity operations.

Brazzel, Jack; Spehar, Pete; Clark, Fred; Foster, Chris; Eldridge, Erin

2013-01-01

26

Tumbling and spaceflight: the Gemini VIII experience.  

PubMed

A malfunctioning orbital flight attitude thruster during the flight of Gemini VIII led to acceleration forces on astronauts Neil Armstrong (commander) and David Scott (pilot) that created the potential for derogation of oculo-vestibular and eye-hand coordination effects. The spacecraft attained an axial tumbling rotation of 50 rpm and would have exceeded this had not the commander accurately diagnosed the problem and taken immediate corrective action. By the time counter-measure controls were applied, both astronauts were experiencing vertigo and the physiological effects of the tumbling acceleration. Data from the recorders reveal that one astronaut experienced -Gy of 0.92 G-units, and the other +Gy of 0.92 for approximately 46 s. Both received a -Gz of 0.89 G-units from the waist up with a +Gz of 0.05 from the waist down. A substantial increase of time and/or an increase in rpm would ultimately have produced incapacitation of both astronauts. NASA corrected the Gemini thruster problem by changing the ignition system wiring. Future space-craft undertaking long-term missions could be equipped with unambiguous thruster fault displays and could have computer-controlled automatic cutoffs to control excessive thruster burns. PMID:2302130

Mohler, S R; Nicogossian, A E; McCormack, P D; Mohler, S R

1990-01-01

27

Optimal cooperative time-fixed impulsive rendezvous  

NASA Astrophysics Data System (ADS)

A method has been developed for determining optimal, i.e., minimum fuel, trajectories for the fixed-time cooperative rendezvous of two spacecraft. The method presently assumes that the vehicles perform a total of three impulsive maneuvers with each vehicle being active, that is, making at least one maneuver. The cost of a feasible 'reference' trajectory is improved by an optimizer which uses an analytical gradient developed using primer vector theory and a new solution for the optimal terminal (rendezvous) maneuver. Results are presented for a large number of cases in which the initial orbits of both vehicles are circular but in which the initial positions of the vehicles and the allotted time for rendezvous are varied. In general, the cost of the cooperative rendezvous is less than that of rendezvous with one vehicle passive. Further improvement in cost may be obtained in the future when additional, i.e., midcourse, impulses are allowed and inserted as indicated for some cases by the primer vector histories which are generated by the program.

Mirfakhraie, Koorosh; Conway, Bruce A.; Prussing, John E.

28

Study of a comet rendezvous mission. Volume 2: Appendices  

NASA Technical Reports Server (NTRS)

Appendices to the comet Encke rendezvous mission consider relative positions of comet, earth and sun; viewing condition for Encke; detection of Taurid meteor streams; ephemeris of comet Encke; microwave and optical techniques in rendezvous mission; approach instruments; electrostatic equilibrium of ion engine spacecraft; comet flyby data for rendezvous spacecraft assembly; observations of P/Encke extracted from a compilation; and summary of technical innovations.

1972-01-01

29

Electro-optical rendezvous and docking sensors  

NASA Technical Reports Server (NTRS)

Electro-optical sensors provide unique and critical functionality for space missions requiring rendezvous, docking, and berthing. McDonnell Douglas is developing a complete rendezvous and docking system for both manned and unmanned missions. This paper examines our sensor development and the systems and missions which benefit from rendezvous and docking sensors. Simulation results quantifying system performance improvements in key areas are given, with associated sensor performance requirements. A brief review of NASA-funded development activities and the current performance of electro-optical sensors for space applications is given. We will also describe current activities at McDonnell Douglas for a fully functional demonstration to address specific NASA mission needs.

Tubbs, David J.; Kesler, Lynn O.; Sirko, Robert J.

1991-01-01

30

Development of an autonomous video rendezvous and docking system, phase 3  

NASA Technical Reports Server (NTRS)

Field-of-view limitations proved troublesome. Higher resolution was required. Side thrusters were too weak. The strategy logic was improved and the Kalman filter was augmented to estimate target attitude and tumble rate. Two separate filters were used. The new filter estimates target attitude and angular momentum. The Newton-Raphson iteration improves image interpretation.

Tietz, J. C.

1984-01-01

31

Trigger Angle Targeting for Orbital Rendezvous  

NASA Astrophysics Data System (ADS)

Orbital rendezvous missions often have a co-elliptic approach phase where a chaser vehicle approaches an object with a near-constant relative altitude and relative velocity. A well known orbital rendezvous technique is to trigger the Terminal Phase Initiation (TPI) maneuver when the apparent elevation of the target reaches some nominal angle. The best elevation trigger angle on which to initiate the final transfer maneuver must balance favorable performance characteristics and desirable operational simplicity. A detailed analysis is given deriving the best trigger angles and showing how these results correlate to past missions and how they could potentially influence future ones.

Woffinden, David C.; Ben Rose, M.; Geller, David K.

2008-12-01

32

On-Board Rendezvous Targeting for Orion  

NASA Technical Reports Server (NTRS)

The Orion On-board GNC system is among the most complex ever developed for a space mission. It is designed to operate autonomously (independent of the ground). The rendezvous system in particular was designed to operate on the far side of the moon, and in the case of loss-of-communications with the ground. The vehicle GNC system is designed to retarget the rendezvous maneuvers, given a mission plan. As such, all the maneuvers which will be performed by Orion, have been designed and are being incorporated into the flight code.

Weeks, Michael W.; DSouza, Christopher N.

2010-01-01

33

Tumbling, an Interactive Way to Move Forward  

NSDL National Science Digital Library

The migration of Drosophila border cells has become a powerful model with which to genetically identify guidance cues that control the directed migration of a group of interconnected cells. During oogenesis, border cells delaminate from an epithelial layer and move collectively toward the oocyte. In vivo observation has been added to the impressive experimental toolkit available to study border cell migration. These studies reveal two previously unknown migratory behaviors: one in which cells within the border cell cluster constantly change their position, and another called "tumbling," by which the entire border cell cluster rotates forward. Unexpectedly, the same receptor tyrosine kinases control these different modes of migration through separate downstream pathways. An early mode is mediated by the actin regulatory proteins ELMO and Mbc and resembles cellular polarization during individual cell migration; whereas during a later phase, communication between cells, facilitated by mitogen-activated protein kinase and phospholipase C–?, organizes the polarity of the entire cluster.

Hiroko Sano (New York University School of Medicine; Howard Hughes Medical Institute and the Kimmel Center for Biology and Medicine of the Skirball Institute REV)

2007-11-13

34

Multiple NEO Rendezvous Using Solar Sails  

NASA Technical Reports Server (NTRS)

Mission concept is to assess the feasibility of using solar sail propulsion to enable a robotic precursor that would survey multiple Near Earth Objects (NEOs) for potential future human visits. Single spacecraft will rendezvous with and image 3 NEOs within 6 years of launch

Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

2012-01-01

35

Multiple NEO Rendezvous Using Solar Sail Propulsion  

NASA Technical Reports Server (NTRS)

The NASA Marshall Space Flight Center (MSFC) Advanced Concepts Office performed an assessment of the feasibility of using a near-term solar sail propulsion system to enable a single spacecraft to perform serial rendezvous operations at multiple Near Earth Objects (NEOs) within six years of launch on a small-to-moderate launch vehicle. The study baselined the use of the sail technology demonstrated in the mid-2000 s by the NASA In-Space Propulsion Technology Project and is scheduled to be demonstrated in space by 2014 as part of the NASA Technology Demonstration Mission Program. The study ground rules required that the solar sail be the only new technology on the flight; all other spacecraft systems and instruments must have had previous space test and qualification. The resulting mission concept uses an 80-m X 80-m 3-axis stabilized solar sail launched by an Athena-II rocket in 2017 to rendezvous with 1999 AO10, Apophis and 2001 QJ142. In each rendezvous, the spacecraft will perform proximity operations for approximately 30 days. The spacecraft science payload is simple and lightweight; it will consist of only the multispectral imager flown on the Near Earth Asteroid Rendezvous (NEAR) mission to 433 Eros and 253 Mathilde. Most non-sail spacecraft systems are based on the Messenger mission spacecraft. This paper will describe the objectives of the proposed mission, the solar sail technology to be employed, the spacecraft system and subsystems, as well as the overall mission profile.

Johnson, Les; Alexander, Leslie; Fabisinski, Leo; Heaton, Andy; Miernik, Janie; Stough, Rob; Wright, Roosevelt; Young, Roy

2012-01-01

36

Credit PSR. This interior view shows the vacuum tumble dryer. ...  

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

Credit PSR. This interior view shows the vacuum tumble dryer. The tumble dryer is lined with a water jacket to maintain temperature during the drying of ammonium perchlorate ("AP"); water enters and exits the dryer jacket through the pipe fittings along the horizontal center line of the dryer. The wall at the right is constructed to blow out in the event of an explosion - Jet Propulsion Laboratory Edwards Facility, Oxidizer Dryer Building, Edwards Air Force Base, Boron, Kern County, CA

37

THE ROLE OF LEAD-UP DRILLS IN TUMBLING  

Microsoft Academic Search

An analysis of three commonly used lead-up drills in tumbling was undertaken to assess the validity in replicating key mechanical variables of a foundation tumble row. Six gymnasts (3 intermediate and 3 elite) were analyzed using a 12-camera Vicon analysis system operating at 250 Hz. Data were then modeled and filtered through Vicon Workstation and processed through Matlab (Version 7.0).

Brllce Elliott; Tameira McLean; Jacque Alderson

38

Tumble stability criterion of integrated locomotion and manipulation  

Microsoft Academic Search

We discuss methods to evaluate the stability of robots which execute manipulations and locomotion. The relationship between the center of gravity projection point and the ground contact points is an easy-to-use criterion but it does not take into consideration manipulation counter-force. We propose a concept called “tumble stability”, which considers the tumble direction when all ground contact points except 2

K. Yoneda; S. Hirose

1996-01-01

39

Designing the STS-134 Re-Rendezvous: A Preparation for Future Crewed Rendezvous Missions  

NASA Technical Reports Server (NTRS)

In preparation to provide the capability for the Orion spacecraft, also known as the Multi-Purpose Crew Vehicle (MPCV), to rendezvous with the International Space Station (ISS) and future spacecraft, a new suite of relative navigation sensors are in development and were tested on one of the final Space Shuttle missions to ISS. The National Aeronautics and Space Administration (NASA) commissioned a flight test of prototypes of the Orion relative navigation sensors on STS-134, in order to test their performance in the space environment during the nominal rendezvous and docking, as well as a re-rendezvous dedicated to testing the prototype sensors following the undocking of the Space Shuttle orbiter at the end of the mission. Unlike the rendezvous and docking at the beginning of the mission, the re-rendezvous profile replicates the newly designed Orion coelliptic approach trajectory, something never before attempted with the shuttle orbiter. Therefore, there were a number of new parameters that needed to be conceived of, designed, and tested for this rerendezvous to make the flight test successful. Additionally, all of this work had to be integrated with the normal operations of the ISS and shuttle and had to conform to the constraints of the mission and vehicles. The result of this work is a separation and rerendezvous trajectory design that would not only prove the design of the relative navigation sensors for the Orion vehicle, but also would serve as a proof of concept for the Orion rendezvous trajectory itself. This document presents the analysis and decision making process involved in attaining the final STS-134 re-rendezvous design.

Stuit, Timothy D.

2011-01-01

40

Dynamic passivation of a spinning and tumbling satellite using free-flying teleoperators.  

NASA Technical Reports Server (NTRS)

A satellite will generally have some initial angular motion. Before the satellite can be retrieved, it will be necessary to null its angular rates. A method is presented for nulling the simultaneous angular rates for cylindrical and near-cylindrical satellites. It is assumed that there are no external torques acting on the satellite initially. A model is being fabricated to verify the analysis. The analysis shows that it is feasible to null the spin and tumble rates for cylindrical and near-cylindrical satellites with an arm attached to a remote manipulator unit.

Faile, G. C.; Counter, D. N.; Bourgeois, E. J.

1973-01-01

41

Autonomous Rendezvous and Docking Conference, volume 1  

NASA Technical Reports Server (NTRS)

This document consists of the presentation submitted at the Autonomous Rendezvous and Docking (ARD) Conference. It contains three volumes: ARD hardware technology; ARD software technology; and ARD operations. The purpose of this conference is to identify the technologies required for an on orbit demonstration of the ARD, assess the maturity of these technologies, and provide the necessary insight for a quality assessment of the programmatic management, technical, schedule, and cost risks.

1990-01-01

42

Manned versus unmanned rendezvous and capture  

NASA Technical Reports Server (NTRS)

Rendezvous and capture (docking) operations may be performed either automatically or under manual control. In cases where humans are far from the mission site, or high-bandwidth communications lines are not in place, automation is the only option. Such might be the case with unmanned missions to the moon or Mars that involve orbital docking or cargo transfer. In crewed situations where sensors, computation capabilities, and other necessary instrumentation are unavailable, manual control is the only alternative. Power, mass, cost, or other restrictions may limit the availability of the machinery required for an automated rendezvous and capture. The only occasions for which there is a choice about whether to use automated or manual control are those where the vehicle(s) have both the crew and instrumentation necessary to perform the mission either way. The following discussion will focus on the final approach or capture (docking) maneuver. The maneuvers required for long-range rendezvous operations are calculated by computers. It is almost irrelevant whether it is an astronaut, watching a count-down timer who pushes the button firing the thruster or whether the computer keeps track of the time and fires with the astronaut monitoring. The actual manual workload associated with a mission that may take as long as hours or days to perform is small. The workload per unit time increases tremendously during the final approach (docking) phase and this is where the issue of manual versus automatic is more important.

Brody, Adam R.

1991-01-01

43

Orion Handling Qualities During ISS Rendezvous and Docking  

NASA Technical Reports Server (NTRS)

The Orion spacecraft was designed to rendezvous with multiple vehicles in low earth orbit (LEO) and beyond. To perform the required rendezvous and docking task, Orion must provide enough control authority to perform coarse translational maneuvers while maintaining precision to perform the delicate docking corrections. While Orion has autonomous docking capabilities, it is expected that final approach and docking operations with the International Space Station (ISS) will initially be performed in a manual mode. A series of evaluations was conducted by NASA and Lockheed Martin at the Johnson Space Center to determine the handling qualities (HQ) of the Orion spacecraft during different docking and rendezvous conditions using the Cooper-Harper scale. This paper will address the specifics of the handling qualities methodology, vehicle configuration, scenarios flown, data collection tools, and subject ratings and comments. The initial Orion HQ assessment examined Orion docking to the ISS. This scenario demonstrates the Translational Hand Controller (THC) handling qualities of Orion. During this initial assessment, two different scenarios were evaluated. The first was a nominal docking approach to a stable ISS, with Orion initializing with relative position dispersions and a closing rate of approximately 0.1 ft/sec. The second docking scenario was identical to the first, except the attitude motion of the ISS was modeled to simulate a stress case ( 1 degree deadband per axis and 0.01 deg/sec rate deadband per axis). For both scenarios, subjects started each run on final approach at a docking port-to-port range of 20 ft. Subjects used the THC in pulse mode with cues from the docking camera image, window views, and range and range rate data displayed on the Orion display units. As in the actual design, the attitude of the Orion vehicle was held by the automated flight control system at 0.5 degree deadband per axis. Several error sources were modeled including Reaction Control System (RCS) jet angular and position misalignment, RCS thrust magnitude uncertainty, RCS jet force direction uncertainty due to self plume impingement, and Orion center of mass uncertainty.

Hart, Jeremy J.; Stephens, J. P.; Spehar, P.; Bilimoria, K.; Foster, C.; Gonzalex, R.; Sullivan, K.; Jackson, B.; Brazzel, J.; Hart, J.

2011-01-01

44

Trajectory control with continuous thrust applied to a rendezvous maneuver  

NASA Astrophysics Data System (ADS)

A rendezvous mission can be divided into the following phases: launch, phasing, far range rendezvous, close range rendezvous and mating (docking or berthing). This paper aims to present a close range rendezvous with closed loop controlled straight line trajectory. The approaching is executed on V-bar axis. A PID controller and continuous thrust are used to eliminate the residual errors in the trajectory. A comparative study about the linear and nonlinear dynamics is performed and the results showed that the linear equations become inaccurate insofar as the chaser moves away from the target.

Santos, W. G.; Rocco, E. M.

2013-10-01

45

Radar Performance Improvement. Angle Tracking Modification to Fire Control Radar System for Space Shuttle Rendezvous  

NASA Technical Reports Server (NTRS)

The AN/APQ-153 fire control radar modified to provide angle tracking was evaluated for improved performance. The frequency agile modifications are discussed along with the range-rate improvement modifications, and the radar to computer interface. A parametric design and comparison of noncoherent and coherent radar systems are presented. It is shown that the shuttle rendezvous range and range-rate requirements can be made by a Ku-Band noncoherent pulse radar.

Little, G. R.

1976-01-01

46

Tumbling of polymers in semidilute solution under shear flow  

E-print Network

The tumbling dynamics of individual polymers in semidilute solution is studied by large-scale non-equilibrium mesoscale hydrodynamic simulations. We find that the tumbling time is equal to the non-equilibrium relaxation time of the polymer end-to-end distance along the flow direction and strongly depends on concentration. In addition, the normalized tumbling frequency as well as the widths of the alignment distribution functions for a given concentration-dependent Weissenberg number exhibit a weak concentration dependence in the cross-over regime from a dilute to a semidilute solution. For semidilute solutions a universal behavior is obtained. This is a consequence of screening of hydrodynamic interactions at polymer concentrations exceeding the overlap concentration.

C. -C. Huang; G. Sutmann; G. Gompper; R. G. Winkler

2011-03-18

47

Optical Signature Analysis of Tumbling Rocket Bodies via Laboratory Measurements  

NASA Technical Reports Server (NTRS)

The NASA Orbital Debris Program Office has acquired telescopic lightcurve data on massive intact objects, specifically spent rocket bodies, in order to ascertain tumble rates in support of the Active Debris Removal (ADR) task to help remediate the LEO environment. Rotation rates are needed to plan and develop proximity operations for potential future ADR operations. To better characterize and model optical data acquired from ground-based telescopes, the Optical Measurements Center (OMC) at NASA/JSC emulates illumination conditions in space using equipment and techniques that parallel telescopic observations and source-target-sensor orientations. The OMC employs a 75-watt Xenon arc lamp as a solar simulator, an SBIG CCD camera with standard Johnson/Bessel filters, and a robotic arm to simulate an object's position and rotation. The light source is mounted on a rotary arm, allowing access any phase angle between 0 -- 360 degrees. The OMC does not attempt to replicate the rotation rates, but focuses on how an object is rotating as seen from multiple phase angles. The two targets studied are scaled (1:48), SL-8 Cosmos 3M second stages. The first target is painted in the standard government "gray" scheme and the second target is primary white, as used for commercial missions. This paper summarizes results of the two scaled rocket bodies, each rotated about two primary axes: (a) a spin-stabilized rotation and (b) an end-over-end rotation. The two rotation states are being investigated as a basis for possible spin states of rocket bodies, beginning with simple spin states about the two primary axes. The data will be used to create a database of potential spin states for future works to convolve with more complex spin states. The optical signatures will be presented for specific phase angles for each rocket body and shown in conjunction with acquired optical data from multiple telescope sources.

Cowardin, H.; Lederer, S.; Liou, J.-C.

2012-01-01

48

Flight operations for Shuttle rendezvous navigation and targeting  

Microsoft Academic Search

An important mission for the Space Shuttle is orbital rendezvous with free-flying satellites for repair and refurbishment. The recent successful rescue of the Solar Maximum Mission (SMM) satellite by the Space Shuttle Challenger emphasizes this fact. The task of completing a rendezvous is one that requires the capability to track the target satellite and autonomously determine the maneuvers necessary to

D. J. Collins

1984-01-01

49

Red blood cells and other non-spherical capsules in shear flow: oscillatory dynamics and the tank-treading-to-tumbling transition  

E-print Network

We consider the motion of red blood cells and other non-spherical microcapsules dilutely suspended in a simple shear flow. Our analysis indicates that depending on the viscosity, membrane elasticity, geometry and shear rate, the particle exhibits either tumbling, tank-treading of the membrane about the viscous interior with periodic oscillations of the orientation angle, or intermittent behavior in which the two modes occur alternately. For red blood cells, we compute the complete phase diagram and identify a novel tank-treading-to-tumbling transition at low shear rates. Observations of such motions coupled with our theoretical framework may provide a sensitive means of assessing capsule properties.

J. M. Skotheim; T. W. Secomb

2006-05-26

50

Comet Encke flyby - Asteroid rendezvous mission  

NASA Technical Reports Server (NTRS)

A multitarget mission mode is described which utilizes the solar electric propulsion (SEP) capability to rendezvous with an asteroid after the encounter with Encke. This mode can be defined as a 'no-risk' Encke flyby mission relative to SEP technology. Launched in mid-1980, the earth-Encke transfer is all-ballistic, and SEP operation begins after comet encounter and is relied upon only to accomplish the secondary target objectives. The discussion is based on an exploratory analysis and is therefore limited in scope to a description of trajectory profile and spacecraft mass characteristics.

Friedlander, A. L.

1974-01-01

51

Autonomous Rendezvous and Docking Conference, volume 2  

NASA Technical Reports Server (NTRS)

Autonomous Rendezvous and Docking (ARD) will be a requirement for future space programs. Clear examples include satellite servicing, repair, recovery, and reboost in the near term, and the longer range lunar and planetary exploration programs. ARD will permit more aggressive unmanned space activities, while providing a valuable operational capability for manned missions. The purpose of the conference is to identify the technologies required for an on-orbit demonstration of ARD, assess the maturity of those technologies, and provide the necessary insight for a quality assessment of programmatic management, technical, schedule, and cost risks.

1990-01-01

52

Concept definition study for recovery of tumbling satellites. Volume 2: Supporting research and technology report  

NASA Technical Reports Server (NTRS)

A number of areas of research and laboratory experiments were identified which could lead to development of a cost efficient remote, disable satellite recovery system. Estimates were planned of disabled satellite motion. A concept is defined as a Tumbling Satellite Recovery kit which includes a modular system, composed of a number of subsystem mechanisms that can be readily integrated into varying combinations. This would enable the user to quickly configure a tailored remote, disabled satellite recovery kit to meet a broad spectrum of potential scenarios. The capability was determined of U.S. Earth based satellite tracking facilities to adequately determine the orientation and motion rates of disabled satellites.

Cable, D. A.; Derocher, W. L., Jr.; Cathcart, J. A.; Keeley, M. G.; Madayev, L.; Nguyen, T. K.; Preese, J. R.

1986-01-01

53

Rough-and-Tumble Play on the Elementary School Playground.  

ERIC Educational Resources Information Center

Discusses rough-and-tumble (R&T) play and misconceptions about its role in the development of young children. Contrasts R&T with aggressive behaviors. Discusses the educational benefits of R&T and offers recommendations for incorporating it into young children's curricula. (Author/RWB)

Pellegrini, A. D.; Perlmutter, Jane C.

1988-01-01

54

Rendezvous radar for the orbital maneuvering vehicle  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

55

Channel-Hopping Based on Available Channel Set for Rendezvous of Cognitive Radios  

E-print Network

Channel-Hopping Based on Available Channel Set for Rendezvous of Cognitive Radios Lu Yu1, Hai Liu1 the rendezvous in finite time, all existing rendezvous algorithms generate CH (channel-hopping) sequences using the whole channel set and attempt rendezvous on each of the channels (i.e., both available channels

Chu, Xiaowen

56

Necessary conditions for tumbling in the rotational motion  

NASA Astrophysics Data System (ADS)

The goal of this work is the investigation of the necessary conditions for the possible existence of tumbling in rotational motion of rigid bodies. In a stable spinning satellite, tumbling may occur by sufficient strong action of external impulses, when the conical movement characteristic of the stable attitude is de-characterized. For this purpose a methodology is chosen to simplify the study of rotational motions with great amplitude, for example free bodies in space, allowing an extension of the analysis to non-conservative systems. In the case of a satellite in space, the projection of the angular velocity along the principal axes of inertia must be known, defining completely the initial conditions of motion for stability investigations. In this paper, the coordinate systems are established according to the initial condition in order to allow a simple analytical work on the equations of motion. Also it will be proposed the definition of a parameter, calling it tumbling coefficient, to measure the intensity of the tumbling and the amplitude of the motion when crossing limits of stability in the concept of Lyapunov. Tumbling in the motion of bodies in space is not possible when this coefficient is positive. Magnus Triangle representation will be used to represent the geometry of the body, establishing regions of stability/instability for possible initial conditions of motion. In the study of nonconservative systems for an oblate body, one sufficient condition will be enough to assure damped motion, and this condition is checked for a motion damped by viscous torques. This paper seeks to highlight the physical understanding of the phenomena and the influence of various parameters that are important in the process.

Carrera, Danny H. Z.; Weber, Hans I.

2012-11-01

57

Orbital rendezvous mission planning using mixed integer nonlinear programming  

NASA Astrophysics Data System (ADS)

The rendezvous and docking mission is usually divided into several phases, and the mission planning is performed phase by phase. A new planning method using mixed integer nonlinear programming, which investigates single phase parameters and phase connecting parameters simultaneously, is proposed to improve the rendezvous mission's overall performance. The design variables are composed of integers and continuous-valued numbers. The integer part consists of the parameters for station-keeping and sensor-switching, the number of maneuvers in each rendezvous phase and the number of repeating periods to start the rendezvous mission. The continuous part consists of the orbital transfer time and the station-keeping duration. The objective function is a combination of the propellant consumed, the sun angle which represents the power available, and the terminal precision of each rendezvous phase. The operational requirements for the spacecraft-ground communication, sun illumination and the sensor transition are considered. The simple genetic algorithm, which is a combination of the integer-coded and real-coded genetic algorithm, is chosen to obtain the optimal solution. A practical rendezvous mission planning problem is solved by the proposed method. The results show that the method proposed can solve the integral rendezvous mission planning problem effectively, and the solution obtained can satisfy the operational constraints and has a good overall performance.

Zhang, Jin; Tang, Guo-jin; Luo, Ya-Zhong; Li, Hai-yang

2011-04-01

58

Pathfinder autonomous rendezvous and docking project  

NASA Technical Reports Server (NTRS)

Capabilities are being developed and demonstrated to support manned and unmanned vehicle operations in lunar and planetary orbits. In this initial phase, primary emphasis is placed on definition of the system requirements for candidate Pathfinder mission applications and correlation of these system-level requirements with specific requirements. The FY-89 activities detailed are best characterized as foundation building. The majority of the efforts were dedicated to assessing the current state of the art, identifying desired elaborations and expansions to this level of development and charting a course that will realize the desired objectives in the future. Efforts are detailed across all work packages in developing those requirements and tools needed to test, refine, and validate basic autonomous rendezvous and docking elements.

Lamkin, Stephen (editor); Mccandless, Wayne (editor)

1990-01-01

59

STS-135: Rendezvous Pitch Maneuver - Duration: 3:15.  

NASA Video Gallery

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

60

Planning and scheduling proximity operations for autonomous orbital rendezvous  

E-print Network

This thesis develops a mixed integer programming formulation to solve the proximity operations scheduling problem for autonomous orbital rendezvous. The algorithm of this thesis allows the operator to specify planned modes, ...

Guerra, Christopher J., 1978-

2003-01-01

61

STS-133: Rendezvous Pitch Maneuver - Duration: 4:08.  

NASA Video Gallery

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

62

Robust optimization of nonlinear impulsive rendezvous with uncertainty  

NASA Astrophysics Data System (ADS)

The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design. A robust optimization design method for a nonlinear rendezvous trajectory with uncertainty is proposed in this paper. One performance index related to the variances of the terminal state error is termed the robustness performance index, and a two-objective optimization model (including the minimum characteristic velocity and the minimum robustness performance index) is formulated on the basis of the Lambert algorithm. A multi-objective, non-dominated sorting genetic algorithm is employed to obtain the Pareto optimal solution set. It is shown that the proposed approach can be used to quickly obtain several inherent principles of the rendezvous trajectory by taking practical errors into account. Furthermore, this approach can identify the most preferable design space in which a specific solution for the actual application of the rendezvous control should be chosen.

Luo, YaZhong; Yang, Zhen; Li, HengNian

2014-01-01

63

Robust optimization of nonlinear impulsive rendezvous with uncertainty  

NASA Astrophysics Data System (ADS)

The optimal rendezvous trajectory designs in many current research efforts do not incorporate the practical uncertainties into the closed loop of the design. A robust optimization design method for a nonlinear rendezvous trajectory with uncertainty is proposed in this paper. One performance index related to the variances of the terminal state error is termed the robustness performance index, and a two-objective optimization model (including the minimum characteristic velocity and the minimum robustness performance index) is formulated on the basis of the Lambert algorithm. A multi-objective, non-dominated sorting genetic algorithm is employed to obtain the Pareto optimal solution set. It is shown that the proposed approach can be used to quickly obtain several inherent principles of the rendezvous trajectory by taking practical errors into account. Furthermore, this approach can identify the most preferable design space in which a specific solution for the actual application of the rendezvous control should be chosen.

Luo, YaZhong; Yang, Zhen; Li, HengNian

2014-04-01

64

Low Earth Orbit Rendezvous Strategy for Lunar Missions  

NASA Technical Reports Server (NTRS)

On January 14, 2004 President George W. Bush announced a new Vision for Space Exploration calling for NASA to return humans to the moon. In 2005 NASA decided to use a Low Earth Orbit (LEO) rendezvous strategy for the lunar missions. A Discrete Event Simulation (DES) based model of this strategy was constructed. Results of the model were then used for subsequent analysis to explore the ramifications of the LEO rendezvous strategy.

Cates, Grant R.; Cirillo, William M.; Stromgren, Chel

2006-01-01

65

Optimal terminal maneuver for a cooperative impulsive rendezvous  

NASA Technical Reports Server (NTRS)

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

Prussing, John E.; Conway, Bruce A.

1989-01-01

66

Statistical Mechanics of Interacting Run-and-Tumble Bacteria  

E-print Network

We consider self-propelled particles undergoing run-and-tumble dynamics (as exhibited by E. coli) in one dimension. Building on previous analyses at drift-diffusion level for the one-particle density, we add both interactions and noise, enabling discussion of domain formation by "self-trapping", and other collective phenomena. Mapping onto detailed-balance systems is possible in certain cases.

J. Tailleur; M. E. Cates

2008-08-14

67

Aperiodic tumbling of microrods advected in a microchannel flow  

E-print Network

We report on an experimental investigation of the tumbling of microrods in the shear flow of a microchannel (40 x 2.5 x 0.4 mm). The rods are 20 to 30 microns long and their diameters are of the order of 1 micron. Images of the centre-of-mass motion and the orientational dynamics of the rods are recorded using a microscope equipped with a CCD camera. A motorised microscope stage is used to track individual rods as they move along the channel. Automated image analysis determines the position and orientation of a tracked rods in each video frame. We find different behaviours, depending on the particle shape, its initial position, and orientation. First, we observe periodic as well as aperiodic tumbling. Second, the data show that different tumbling trajectories exhibit different sensitivities to external perturbations. These observations can be explained by slight asymmetries of the rods. Third we observe that after some time, initially periodic trajectories lose their phase. We attribute this to drift of the centre of mass of the rod from one to another stream line of the channel flow.

J. Einarsson; A. Johansson; S. K. Mahato; Y. Mishra; J. R. Angilella; D. Hanstorp; B. Mehlig

2012-11-24

68

Aperiodic tumbling of microrods advected in a microchannel flow  

E-print Network

We report on an experimental investigation of the tumbling of microrods in the shear flow of a microchannel (40 x 2.5 x 0.4 mm). The rods are 20 to 30 microns long and their diameters are of the order of 1 micron. Images of the centre-of-mass motion and the orientational dynamics of the rods are recorded using a microscope equipped with a CCD camera. A motorised microscope stage is used to track individual rods as they move along the channel. Automated image analysis determines the position and orientation of a tracked rods in each video frame. We find different behaviours, depending on the particle shape, its initial position, and orientation. First, we observe periodic as well as aperiodic tumbling. Second, the data show that different tumbling trajectories exhibit different sensitivities to external perturbations. These observations can be explained by slight asymmetries of the rods. Third we observe that after some time, initially periodic trajectories lose their phase. We attribute this to drift of the c...

Einarsson, J; Mahato, S K; Mishra, Y; Angilella, J R; Hanstorp, D; Mehlig, B

2013-01-01

69

Concept definition study for recovery of tumbling satellites. Volume 1: Executive summary, study results  

NASA Technical Reports Server (NTRS)

The first assessment is made of the design requirements and conceptual definition of a front end kit to be transported on the currently defined Orbital Maneuvering Vehicle (OMV) and the Space Transportation System Shuttle Orbiter, to conduct remote, teleoperated recovery of disabled and noncontrollable, tumbling satellites. Previous studies did not quantify the dynamic characteristics of a tumbling satellite, nor did they appear to address the full spectrum of Tumbling Satellite Recovery systems requirements. Both of these aspects are investigated with useful results.

Cable, D. A.; Derocher, W. L., Jr.; Cathcart, J. A.; Keeley, M. G.; Madayev, L.; Nguyen, T. K.; Preese, J. R.

1986-01-01

70

Endoscopic Rendezvous Procedure for Ureteral Iatrogenic Detachment: Report of a Case Series with Long-Term Outcomes.  

PubMed

Abstract Background and Purpose: Injury to the ureter is the most common urologic complication of pelvic surgery, with an incidence that ranges from 1% to 10%. Most cases of ureteral injuries are related to gynecologic procedures. The ureter is particularly vulnerable to detachment or ligation during hysterectomy because of its position from the lateral edge of the cervix. We report a case series of female patients who underwent the ureteral rendezvous procedure for ureteral detachment. Patients and Methods: Between January 2009 and April 2013, 18 ureteral rendezvous procedures were performed for patients with complete detachment. We assessed the operative and clinical outcomes of these patients over a mean follow-up duration of 26.5 months and describe the three most representative cases. Results: The endoscopic rendezvous technique was performed in all cases to manage ureteral detachment. CT urography at discharge and 6 and 12 months after discharge confirmed the restoration of ureteral integrity without any leakage in 66% (12/18) patients, indicated ureteral stenosis in 22% (4/18) patients, and indicated ureteral leakage in 12% (2/18) patients. The overall long-term success rate for all 18 patients was 78% (14/18) at a mean follow-up of 26.5 months. Conclusions: The endoscopic rendezvous procedure reduces the need for invasive open surgical repair and represents the optimal initial option in patients with iatrogenic ureteral lesions before invasive procedures with higher morbidity are attempted. PMID:25226409

Pastore, Antonio Luigi; Palleschi, Giovanni; Silvestri, Luigi; Leto, Antonino; Autieri, Domenico; Ripoli, Andrea; Maggioni, Cristina; Al Salhi, Yazan; Carbone, Antonio

2014-11-18

71

Tank-treading, swinging, and tumbling of liquid-filled elastic capsules in shear flow.  

PubMed

The dynamic motion of three-dimensional (3D) capsules in a shear flow is investigated by direct numerical simulation. The capsules are modeled as Newtonian liquid droplets enclosed by elastic membranes, with or without considering the membrane-area incompressibility. The internal liquid of the capsules is the same as that outside. The dynamic motion of capsules with initially spherical and oblate spheroidal unstressed shapes is studied under various shear rates. The results show that spherical capsules deform to stationary configurations and then the membranes rotate around the liquid inside (steady tank-treading motion). Such a steady mode is not observed for oblate spheroidal capsules. It is shown that with the shear rate decreasing, the motion of oblate spheroidal capsules changes from the swinging mode (a capsule undergoes periodic shape deformation and inclination oscillation while its membrane is rotating around the liquid inside) to tumbling mode. PMID:18351937

Sui, Y; Low, H T; Chew, Y T; Roy, P

2008-01-01

72

Automated Rendezvous and Capture System Development and Simulation for NASA  

NASA Technical Reports Server (NTRS)

The United States does not have an Automated Rendezvous and Capture/Docking (AR and C) capability and is reliant on manned control for rendezvous and docking of orbiting spacecraft. This reliance on the labor intensive manned interface for control of rendezvous and docking vehicles has a significant impact on the cost of the operation of the International Space Station (ISS) and precludes the use of any U.S. expendable launch capabilities for Space Station resupply. The Soviets have the capability to autonomously dock in space, but their system produces a hard docking with excessive force and contact velocity. Automated Rendezvous and Capture/Docking has been identified as a key enabling technology for the Space Launch Initiative (SLI) Program, DARPA Orbital Express and other DOD Programs. The development and implementation of an AR&C capability can significantly enhance system flexibility, improve safety, and lower the cost of maintaining, supplying, and operating the International Space Station. The Marshall Space Flight Center (MSFC) has conducted pioneering research in the development of an automated rendezvous and capture (or docking) (AR and C) system for U.S. space vehicles. This AR&C system was tested extensively using hardware-in-the-loop simulations in the Flight Robotics Laboratory, and a rendezvous sensor, the Video Guidance Sensor was developed and successfully flown on the Space Shuttle on flights STS-87 and STS-95, proving the concept of a video- based sensor. Further developments in sensor technology and vehicle and target configuration have lead to continued improvements and changes in AR&C system development and simulation. A new Advanced Video Guidance Sensor (AVGS) with target will be utilized on the Demonstration of Autonomous Rendezvous Technologies (DART) flight experiment in 2004.

Roe, Fred D.; Howard, Richard T.; Murphy, Leslie

2004-01-01

73

Polishing and local planarization of plastic spherical capsules using tumble finishing  

NASA Astrophysics Data System (ADS)

A new method (a variant of tumble finishing) for polishing and achieving local planarization on precision spherical, plastic capsules is described. Such capsules have niche applications, such as ablators used in high-peak-power laser targets for fusion energy research. The as-manufactured ablators contain many shallow domes (many 100's of nm high and a few 10's of ?m wide) on the outer surface which are undesirable due to contributions to instabilities during implosion. These capsules were polished (i.e., tumble finished) by rotating a cylindrical vial containing the capsule, many borosilicate glass or zirconia media, and an aqueous-based colloidal silica polishing slurry. During tumble finishing, the relative media/capsule motions cause multiple, random sliding spherical-spherical Hertzian contacts, resulting in material removal, and possibly plastic deformation, on the capsule. As a result, the domes were observed to locally planarize (i.e., converge to lower heights). Utilizing the correct kinematics (i.e., the characteristics of the media/capsule motions), as controlled by the vial rotation rate and the fill fraction of media and slurry, the high velocity downward circumferential media motions were avoided, preventing fracturing of the fragile capsules. Also, the resulting post-polished surface roughness on the capsule was found to scale with the initial media surface roughness. Hence, pre-polishing the media greatly reduced the roughness of the media and thus the roughness of the polished capsule. A material removal model is described based on the Preston model and spherical-spherical Hertzian contacts which shows reasonable agreement with measured average removal rates of 35 ± 15 nm/day and which serves as a valuable tool to scale the polishing behavior with changes in process variables. Narrow domes were observed to planarize more rapidly than wider domes. A local planarization convergence model is also described, based on the concept of workpiece-lap mismatch where the local pressure, and hence removal, varies with the gap at the interface contact. The calculated rate and shape evolution of various size isolated domes compares well with the experimental data.

Suratwala, T. I.; Steele, W. A.; Feit, M. D.; Moreno, K.; Stadermann, M.; Fair, J.; Chen, K.; Nikroo, A.; Youngblood, K.; Wu, K.

2012-11-01

74

WISE Observations of Rendezvous Mission Candidate Comets  

NASA Astrophysics Data System (ADS)

In 1992, Osip et al. wrote: "Several comet flyby and/or rendezvous missions are currently being planned, for which supporting groundbased data from previous apparitions should prove useful. Here, we discuss groundbased narrowband photometry obtained over the last 15 years for nine candidate comets, five of which have been observed on multiple apparitions -- we derive limits on the size of each cometary nucleus. In order to facilitate spacecraft mission planning, we also present molecular abundance ratios, note variations in cometary activity as a function of orbital position and between apparitions, and note the overall degree of dustiness. A detailed analysis of the characteristics of these nine viable mission candidates will provide necessary information for prioritizing targets for any future missions." In this work, we update Osip et al.'s 1992 work using recent photometric infrared observations of the best candidate comet spacecraft targets observed by WISE and other (IRAS, MSX, ISO, Spitzer) infrared space telescopes. The comets studied include 2P/Encke, 9P/Tempel 1, 10P Tempe1 2, 19P/Borrelly, 22P/Kopff, 67P/Churyumov-Gerasimenko, 81P/Wild, 103P/Hartley 2, 107P/Wilson-Harrington. We present imagery, photometry, and temporal trend data, and derived estimates of the dust mass, spatial distribution, albedo/emissivity, and PSD for each comet.

Lisse, Carey M.; Bauer, J. M.; Fernandez, Y. R.; Mainzer, A. K.; Walker, R. G.; Meech, K. J.; Grav, T.; Weissman, P. R.; Kramer, E.; Stevenson, R.

2012-10-01

75

Advanced Multipurpose Rendezvous Tracking System Study  

NASA Technical Reports Server (NTRS)

Rendezvous and docking (R&D) sensors needed to support Earth orbital operations of vehicles were investigated to determine the form they should take. An R&D sensor must enable an interceptor vehicle to determine both the relative position and the relative attitude of a target vehicle. Relative position determination is fairly straightforward and places few constraints on the sensor. Relative attitude determination, however, is more difficult. The attitude is calculated based on relative position measurements of several reflectors placed in a known arrangement on the target vehicle. The constraints imposed on the sensor by the attitude determination method are severe. Narrow beamwidth, wide field of view (fov), high range accuracy, and fast random scan capability are all required to determine attitude by this method. A consideration of these constraints as well as others imposed by expected operating conditions and the available technology led to the conclusion that the sensor should be a cw optical radar employing a semiconductor laser transmitter and an image dissector receiver.

Laurie, R. J.; Sterzer, F.

1982-01-01

76

A Monte-Carlo performance analysis of Kalman filter and targeting algorithms for autonomous orbital rendezvous  

E-print Network

Autonomous orbital rendezvous with an orbiting sample (OS) is seen as an enabling technology for a Mars Sample Return (MSR) mission, so several demonstrations have been planned. With CNES cooperation a proposed rendezvous ...

Vaughan, Andrew Thomas, 1979-

2004-01-01

77

Constant thrust fuel-optimal control for spacecraft rendezvous  

NASA Astrophysics Data System (ADS)

In this paper, constant thrust rendezvous is studied and the optimal rendezvous time is calculated by using continuous genetic algorithm. Firstly, the relative position parameters of the target spacecraft are obtained by using the vision measurement and the target maneuver positions are calculated through the isochronous interpolation method. Then, the results of the calculation of constant thrust rendezvous is founded by processing with multivariate linear regression method. Next, a new switching control law is designed based on the thrust acceleration sequence and the on time of thrusters which can be computed by the time series analysis method. The perturbations and fuel consumptions are addressed during the computation of the on time of thrusters. At last, a monte carlo analysis is performed to calculate the relative velocities at which the rendezvous maneuvers can be carried out and simulation examples are given to illustrate the validity of the method presented in this paper. The simulation results show that with the switching control law can ensure the success of the rendezvous.

Qi, Yongqiang; Jia, Yingmin

2012-04-01

78

Rough and Tumble, Friendship, and Dominance in Schoolchildren: Evidence for Continuity and Change with Age.  

ERIC Educational Resources Information Center

Investigated play-fighting and chasing among 7-, 9-, and 11-year-olds in their school playground, where rough and tumble behaviors occupied approximately 10 percent of the time of 94 students. Findings indicated that rough and tumble tended to occur in a friendly, nonaggressive context. The importance of partner's strength increased with age.…

Humphreys, Anne P.; Smith, Peter K.

1987-01-01

79

A Longitudinal Study of Popular and Rejected Children's Rough-and-Tumble Play.  

ERIC Educational Resources Information Center

Examined longitudinal associations between the rough-and-tumble play of popular and rejected children and measures of their social affiliation and social cognition. Results suggest that rough-and-tumble play for popular, but not rejected, children predicts aspects of social affiliation and social cognitive status. (Author/GLR)

Pellegrini, A. D.

1991-01-01

80

Elementary-School Children's Rough-and-Tumble Play and Social Competence.  

ERIC Educational Resources Information Center

Observations of playground behavior of kindergarteners and second- and fourth-grade students suggested that rough-and-tumble play led to games-with-rules for popular children, and to aggression for rejected children. Findings are discussed in terms of possible effects of the sociometric composition of rough-and-tumble play groups. (RH)

Pellegrini, A. D.

1988-01-01

81

Mobile Agent Rendezvous in a Ring Evangelos Kranakis Danny Krizanc y Nicola Santoro Cindy Sawchuk  

E-print Network

Mobile Agent Rendezvous in a Ring Evangelos Kranakis #3; Danny Krizanc y Nicola Santoro #3; Cindy Sawchuk #3; Abstract In the rendezvous search problem, two mobile agents must move along the n nodes of a network so as to minimize the time required to meet or rendezvous. When the mobile agents are identical

Devoto, Stephen H.

82

Rendezvous missions: From ISS to lunar space station  

NASA Astrophysics Data System (ADS)

There was a lot of experience gained in the rendezvous of different vehicles in the LEO during the years of human space exploration. In the framework of the Apollo program when the astronauts landed on the surface of the Moon, the docking of the Lunar Module launched from the Moon's surface to the Apollo Command Module was successfully implemented in the near-Moon orbit. Presently many space agencies are considering a return to the Moon. It is necessary to solve the new task of docking the vehicle launched from the Earth to the long-term near-Moon orbital station taking into account specific constraints. Based on the ISS experience the author proposes a number of ballistic rendezvous strategies that provide for docking to the near-Moon orbital station with minimum propellant consumption. The trade-off analysis of the given rendezvous strategies is presented.

Murtazin, Rafail

2014-08-01

83

Laser space rendezvous and docking system study continuation  

NASA Technical Reports Server (NTRS)

Investigations were made of a configuration for a spaceborne laser radar (ladar) to meet the requirements for rendezvous and docking with a cooperative object in synchronous orbit. An analysis was completed of laser phase locking techniques, while experimental verification was made of pulse repetition frequency and resonant scanning control loops. Data measurements on a satellite mock-up were also made. The investigation supports the original contention that a rendezvous and docking ladar can be configured to offer a cost effective and reliable solution to envisioned space missions.

Adelman, S.; Heynau, H.; Levinson, S.; Weindling, F.

1977-01-01

84

Crossover from tumbling to tank-treading-like motion in dense simulated suspensions of red blood cells  

E-print Network

Via computer simulations, we provide evidence that the shear rate induced red blood cell tumbling-to-tank-treading transition also occurs at quite high volume fractions, where collective effects are important. The transition takes place as the ratio of suspension stress to the characteristic cell membrane stress exceeds a certain value, independent of volume fraction and cell deformability. This value coincides with that for a transition from an orientationally less ordered to a highly ordered phase. The average cell deformation does not show any signature of the transition, but rather follows a simple scaling law independent of volume fraction.

Timm Krüger; Markus Gross; Dierk Raabe; Fathollah Varnik

2013-12-12

85

Rendezvous Based Trust Propagation to Enhance Distributed Network Security  

E-print Network

Rendezvous Based Trust Propagation to Enhance Distributed Network Security Ningning Cheng, Kannan of the modern day trustworthy networks. Trust can be exploited to mitigate the security threats in wireless to improve the security in the network [1]. If a node gets the trust information of other nodes in advance

California at Davis, University of

86

Management and Conservation Article Surveying Predicted Rendezvous Sites to  

E-print Network

of gray wolves (Canis lupus) in Idaho, USA (Bangs and Fritts 1996). The United States Fish and Wildlife from the Endangered Species list (USFWS 2009). An expected decrease in federal funding followingManagement and Conservation Article Surveying Predicted Rendezvous Sites to Monitor Gray Wolf

Mitchell, Mike

87

Joint certificate marking historical moment during ASTP rendezvous  

NASA Technical Reports Server (NTRS)

The hands of Cosmonaut Valerly N. Kubasov are seen as the ASTP engineer adds his name to the signature on the Soviet side of the Offical joint certificate marking an historical moment during rendezvous day of the Apollo-Soyuz Test Project. The left hand of Astronaut Donald K. Slayton, NASA's docking module pilot, is seen at left.

1975-01-01

88

Performance of Concurrent Rendezvous Systems with Complex Pipeline Structures  

E-print Network

Performance of Concurrent Rendezvous Systems with Complex Pipeline Structures Real February 11, 1998 Abstract The term ``complex pipeline'' describes a set of tasks which process incoming data in a sequence, like a pipeline, but have various kinds of parallel execution steps coupled

Woodside, C. Murray

89

Rendezvous radar modification and evaluation. [for space shuttles  

NASA Technical Reports Server (NTRS)

The purpose of this effort was to continue the implementation and evaluation of the changes necessary to add the non-cooperative mode capability with frequency diversity and a doppler filter bank to the Apollo Rendezvous Radar while retaining the cooperative mode capability.

1976-01-01

90

Successful Development of an Automated Rendezvous and Capture System  

NASA Technical Reports Server (NTRS)

During the 1990's, the Marshall Space Flight Center (MSFC) conducted pioneering research in the development of an automated rendezvous and capture/docking system for U.S. space vehicles. Development and demonstration of a rendezvous sensor was identified early in the AR&C Program as the critical enabling technology that allows automated proximity operations and docking. A first generation rendezvous sensor, the Video Guidance Sensor (VGS) was developed and successfully flown on STS 87 and again on STS 95, proving the concept of a video-based sensor. Advances in both video and signal processing technologies and the lessons learned from the two successful flight experiments provided a baseline for the development, by the MSFC, of a new generation of video based rendezvous sensor. The Advanced Video Guidance Sensor (AVGS) has greatly increased performance and additional capability for longer-range operation with a new Target designed as a direct replacement for existing ISS hemispherical reflectors. A ground demonstration of the entire system and software was successfully tested.

Roe, Fred D.; Howard, Richard T.

2002-01-01

91

Motion Control of Tumbling Spacecraft by Repetitive Impulse Inputs  

NASA Astrophysics Data System (ADS)

An angular momentum control of a tumbling spacecraft by applying repetitive impulses from a space robot arm is discussed. By assuming inputs by the arm, the direction, size and timing of the input forces are relatively free to choose. At each control timing, however, torques parallel to the contact direction cannot be generated. Therefore, the design of controller is not straightforward. To solve this difficulty, the equations of rotational motion are rewritten into simpler forms by applying appropriate coordinates transformation. Then a discrete controller is designed so that the component of the angular momentum parallel to the contact direction is damped out by choosing the directions of input forces properly. The closed loop characteristics considering constant disturbance torques and contact model uncertainty are discussed. Numerical simulations are given to show that the angular momentum is efficiently damped.

Yoshikawa, Shoji; Yamada, Katsuhiko

92

Production of mineral aggregates in quartz tumbling experiments  

NASA Astrophysics Data System (ADS)

Introduction Tumbling experiments with quartz sand with the purpose of tracing the effect of broken bonds in mineral surfaces resulted in an unexpected production of aggregates. These aggregates are a few microns in diameter, spherical and resembling tiny white "snowballs." Particle comminution by aeolian and other natural weathering processes are known in soil science and is often seen as an increase of fine particles towards the top of soil profiles (Nørnberg, P. 1987, 1988, 2002, J.S. Wright 2007). When mineral grains collide in aeolian processes they break up along weakness zones in the crystal lattice. This mechanism causes broken bonds between atoms in the crystal lattice and results in reactive groups in the mineral surface. This mechanism provides the background for experiments to investigate the oxidation processes of magnetite on the planet Mars. The primary magnetic iron oxide phase on Mars is to day known to be magnetite and the colour of the dust on Mars is most likely due to hematite. To investigate if the oxidation process could take place without going over dissolution and precipitation in water, experiments with tumbling of quartz grains in sealed glass containers along with magnetite were started. The idea was that activated bonds at the surface of quartz could oxidize magnetite and convert it to hematite over time. This proved to be the case (Merrison, J.P. et al. 2010). However, in these experiments we observed the formation of the white aggregates which has been the subject of the study that we present here. Results of tumbling experiments Commercially available quarts (Merck) was sieved to obtain the fraction between 125 and 1000 µm. This fraction was tumbled in glass containers for months and resulted in production of a significant amount of fine grained material (Merrison, J.P et al. 2010). A part of this fine fraction consists of the "snowball"-like aggregates which is a fragile element with relatively high specific surface. The physical properties of these structures will be discussed in this paper. Nørnberg, P. 1977: Soil Profile Development in Sands of Varying Age in Vendsyssel, Denmark. Catena, 4, 165-179. Nørnberg, P. 1980: Mineralogy of a podzol formed in sandy materials in Northern Denmark. Geoderma, 24, 25-43. Nørnberg, P. 2002: Particle comminution and aeolian addition in young dune sand soils. Transactions, 17th World Congress of Soil Science, Bangkok, Thailand, Symp. 25, pp. 9. Janet S. Wright, Janet S. 2007: An overview of the role of weathering in the production of quartz silt Sedimentary Geology, 202, 337-351 Merrison, J.P., Gunnlaugsson, H.P., Nørnberg, P., Jensen, A.E., Rasmussen, K.R. 2007: Determination of the Wind Induced Detachment Threshold for Granular Material on Mars using Wind Tunnel Simulations. Icarus, 191, 568-580.

Nørnberg, Per; Finster, Kai; Pall Gunnlaugsson, Haraldur; Knak Jensen, Svend; Merrison, Jonathan Peter

2013-04-01

93

Robot Acting on Moving Bodies (RAMBO): Interaction with tumbling objects  

NASA Technical Reports Server (NTRS)

Interaction with tumbling objects will become more common as human activities in space expand. Attempting to interact with a large complex object translating and rotating in space, a human operator using only his visual and mental capacities may not be able to estimate the object motion, plan actions or control those actions. A robot system (RAMBO) equipped with a camera, which, given a sequence of simple tasks, can perform these tasks on a tumbling object, is being developed. RAMBO is given a complete geometric model of the object. A low level vision module extracts and groups characteristic features in images of the object. The positions of the object are determined in a sequence of images, and a motion estimate of the object is obtained. This motion estimate is used to plan trajectories of the robot tool to relative locations rearby the object sufficient for achieving the tasks. More specifically, low level vision uses parallel algorithms for image enhancement by symmetric nearest neighbor filtering, edge detection by local gradient operators, and corner extraction by sector filtering. The object pose estimation is a Hough transform method accumulating position hypotheses obtained by matching triples of image features (corners) to triples of model features. To maximize computing speed, the estimate of the position in space of a triple of features is obtained by decomposing its perspective view into a product of rotations and a scaled orthographic projection. This allows use of 2-D lookup tables at each stage of the decomposition. The position hypotheses for each possible match of model feature triples and image feature triples are calculated in parallel. Trajectory planning combines heuristic and dynamic programming techniques. Then trajectories are created using dynamic interpolations between initial and goal trajectories. All the parallel algorithms run on a Connection Machine CM-2 with 16K processors.

Davis, Larry S.; Dementhon, Daniel; Bestul, Thor; Ziavras, Sotirios; Srinivasan, H. V.; Siddalingaiah, Madhu; Harwood, David

1989-01-01

94

Effect of phosphate with tumbling on lipid oxidation of precooked roast beef.  

PubMed

This study was a 4×2×4 factorial experiment, sodium tripolyphosphate (0, 0.25, 0.4 and 0.5%), tumbling (nontumbled and tumbled), and storage time (day 0, 2, 4 and 7). Cooking yield was dependent on the level of phosphate and tumbling. For thiobarbituric acid reactive substances (TBARS) values, only sodium tripolyphosphate level and storage time had a significant two-way interaction. The TBARS value of tumbled roast beef with phosphates was the same as that of nontumbled roast beef. For the interaction of phosphate level and storage time, roast beef without phosphate had the significantly highest TBARS values compared with other phosphate levels at day 4 of storage. At day 7, the addition of 0.5% phosphate maintained the oxidative stability of precooked roast beef. The use of 0.5% sodium tripolyphosphate, an iron chelator, should be an effective strategy to reduce the formation of TBARS in precooked roast beef. PMID:22063779

Cheng, Jen-Hua; Ockerman, Herbert W

2003-12-01

95

Dynamics and control of escape and rescue from a tumbling spacecraft  

NASA Technical Reports Server (NTRS)

The results of 18 months of investigations are reported. A movable mass control system to convert the tumbling motion of a spacecraft into simple spin was studied along with the optimization techniques for generating displacement profiles for a tumbling asymmetrical body. Equations of motion are discussed for two asymmetrical vehicles with flexible beams and one spacecraft with flexible solar arrays. The characteristics which allow reasonable safety and reliability in bailout are also discussed.

Kaplan, M. H.

1972-01-01

96

Quantitative characterization of agglomerate abrasion in a tumbling blender by using the Stokes number approach.  

PubMed

Removal of microcrystalline cellulose agglomerates in a dry-mixing system (lactose, 100 M) predominantly occurs via abrasion. The agglomerate abrasion rate potential is estimated by the Stokes abrasion (StAbr) number of the system. The StAbr number equals the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. Basically, the StAbr number concept describes the blending condition of the dry-mixing system. The concept has been applied to investigate the relevance of process parameters on agglomerate abrasion in tumbling blenders. Here, process parameters such as blender rotational speed and relative fill volumes were investigated. In this study, the StAbr approach revealed a transition point between abrasion rate behaviors. Below this transition point, a blending condition exists where agglomerate abrasion is dominated by the kinetic energy density of the powder blend. Above this transition point, a blending condition exists where agglomerates show (undesirable) slow abrasion rates. In this situation, the blending condition is mainly determined by the high fill volume of the filler. PMID:23250711

Willemsz, Tofan A; Nguyen, Tien Thanh; Hooijmaijers, Ricardo; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

2013-03-01

97

Genetic algorithm based fuzzy control of spacecraft autonomous rendezvous  

NASA Technical Reports Server (NTRS)

The U.S. Bureau of Mines is currently investigating ways to combine the control capabilities of fuzzy logic with the learning capabilities of genetic algorithms. Fuzzy logic allows for the uncertainty inherent in most control problems to be incorporated into conventional expert systems. Although fuzzy logic based expert systems have been used successfully for controlling a number of physical systems, the selection of acceptable fuzzy membership functions has generally been a subjective decision. High performance fuzzy membership functions for a fuzzy logic controller that manipulates a mathematical model simulating the autonomous rendezvous of spacecraft are learned using a genetic algorithm, a search technique based on the mechanics of natural genetics. The membership functions learned by the genetic algorithm provide for a more efficient fuzzy logic controller than membership functions selected by the authors for the rendezvous problem. Thus, genetic algorithms are potentially an effective and structured approach for learning fuzzy membership functions.

Karr, C. L.; Freeman, L. M.; Meredith, D. L.

1990-01-01

98

Mars Rover Sample Return ascent, rendezvous, and return to earth  

NASA Technical Reports Server (NTRS)

Ascent, rendezvous and earth return are three operational mission sequences in the sample return phase of the Mars Rover Sample Return (MRSR) mission. In the conduct of the current study, several vehicles have been identified to enable the sample return phase of the mission. These elements are the Mars Ascent Vehicle (MAV), the Earth Return Vehicle (ERV), the rendezvous and docking module (RDM), and the sample return capsule (SRC). The sample return elements, when combined with other elements performing the launch and delivery functions, form the basis of the MRSR system. This paper summarizes the significant mission aspects of the sample return phase, describes the Mars ascent and earth return scenario, illustrates the conceptual designs developed for the MAV, ERV, RDM, and SRC, and discusses the results of significant trade studies conducted.

Lance, Nick

1989-01-01

99

Trajectory Control of Rendezvous with Maneuver Target Spacecraft  

NASA Technical Reports Server (NTRS)

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

Zhou, Zhinqiang

2012-01-01

100

Development of control and autonomy algorithms for docking to complex tumbling satellites  

E-print Network

The capability of automated rendezvous and docking is a key enabling technology for many government and commercial space programs. Future space systems will employ a high level of autonomy to acquire, repair, refuel, and ...

Fejzi?, Amer

2008-01-01

101

Apollo experience report: Evolution of the rendezvous-maneuver plan for the lunar-landing missions  

NASA Technical Reports Server (NTRS)

The evolution of the nominal rendezvous-maneuver plan for the lunar landing missions is presented along with a summary of the significant development for the lunar module abort and rescue plan. A general discussion of the rendezvous dispersion analysis that was conducted in support of both the nominal and contingency rendezvous planning is included. Emphasis is placed on the technical developments from the early 1960's through the Apollo 15 mission (July to August 1971), but pertinent organizational factors also are discussed briefly. Recommendations for rendezvous planning for future programs relative to Apollo experience also are included.

Alexander, J. D.; Becker, R. W.

1973-01-01

102

Low-thrust mission risk analysis, with application to a 1980 rendezvous with the comet Encke  

NASA Technical Reports Server (NTRS)

A computerized failure process simulation procedure is used to evaluate the risk in a solar electric space mission. The procedure uses currently available thrust-subsystem reliability data and performs approximate simulations of the thrust sybsystem burn operation, the system failure processes, and the retargeting operations. The method is applied to assess the risks in carrying out a 1980 rendezvous mission to the comet Encke. Analysis of the results and evaluation of the effects of various risk factors on the mission show that system component failure rates are the limiting factors in attaining a high mission relability. It is also shown that a well-designed trajectory and system operation mode can be used effectively to partially compensate for unreliable thruster performance.

Yen, C. L.; Smith, D. B.

1973-01-01

103

The Stochastic Rendezvous Network Model for Performance of Synchronous ClientServerlike  

E-print Network

The Stochastic Rendezvous Network Model for Performance of Synchronous Client with synchronous communication via rendezvous is found in client­server systems and in proposed Open Distributed industrial software systems. Keywords: client­server, remote procedure call, software performance

Woodside, C. Murray

104

The Stochastic Rendezvous Network Model for Performance of Synchronous Client-Server-like Distributed Software  

Microsoft Academic Search

Distributed or parallel software with synchronous communication via rendezvous isfound in client-server systems and in proposed Open Distributed Systems, in implementationenvironments such as Ada, V, Remote Procedure Call systems, in Transputersystems, and in specification techniques such as CSP, CCS and LOTOS. The delaysinduced by rendezvous can cause serious performance problems, which are not easy toestimate using conventional models which focus

C. Murray Woodside; John E. Neilson; Dorina C. Petriu; Shikharesh Majumdar

1995-01-01

105

Reference equations of motion for automatic rendezvous and capture  

NASA Technical Reports Server (NTRS)

The analysis presented in this paper defines the reference coordinate frames, equations of motion, and control parameters necessary to model the relative motion and attitude of spacecraft in close proximity with another space system during the Automatic Rendezvous and Capture phase of an on-orbit operation. The relative docking port target position vector and the attitude control matrix are defined based upon an arbitrary spacecraft design. These translation and rotation control parameters could be used to drive the error signal input to the vehicle flight control system. Measurements for these control parameters would become the bases for an autopilot or feedback control system (FCS) design for a specific spacecraft.

Henderson, David M.

1992-01-01

106

Virtual reality applications to automated rendezvous and capture  

NASA Technical Reports Server (NTRS)

Virtual Reality (VR) is a rapidly developing Human/Computer Interface (HCI) technology. The evolution of high-speed graphics processors and development of specialized anthropomorphic user interface devices, that more fully involve the human senses, have enabled VR technology. Recently, the maturity of this technology has reached a level where it can be used as a tool in a variety of applications. This paper provides an overview of: VR technology, VR activities at Marshall Space Flight Center (MSFC), applications of VR to Automated Rendezvous and Capture (AR&C), and identifies areas of VR technology that requires further development.

Hale, Joseph; Oneil, Daniel

1991-01-01

107

Universal Lambert and Kepler algorithms for autonomous rendezvous  

NASA Technical Reports Server (NTRS)

This paper describes Lambert and Kepler algorithms designed to be the core of an autonomous rendezvous guidance system for an onboard computer. Applications include robotic and piloted missions to the moon and planets. Flight software must be compact, fast, and totally reliable. Although high accuracy is not essential for flight, in double precision these algorithms are accurate to at least 14 places almost everywhere. Both are universal; they apply to elliptic, parabolic, hyperbolic, and even rectilinear trajectories. The algorithms are improvements to those published by Battin (1987).

Klumpp, Allan R.

1990-01-01

108

Electron paramagnetic resonance studies of slowly tumbling vanadyl spin probes in nematic liquid crystals  

NASA Technical Reports Server (NTRS)

An analysis of EPR line shapes by the method of Polnaszek, Bruno, and Freed is made for slowly tumbling vanadyl spin probes in viscous nematic liquid crystals. The use of typical vanadyl complexes as spin probes for nematic liquid crystals is shown to simplify the theoretical analysis and the subsequent interpretation. Rotational correlation times tau and orientational ordering parameters S sub Z where slow tumbling effects are expected to be observed in vanadyl EPR spectra are indicated in a plot. Analysis of the inertial effects on the probe reorientation, which are induced by slowly fluctuating torque components of the local solvent structure, yield quantitative values for tau and S sub Z. The weakly ordered probe VOAA is in the slow tumbling region and displays these inertial effects throughout the nematic range of BEPC and Phase V. VOAA exhibits different reorientation behavior near the isotropic-nematic transition temperature than that displayed far below this transition temperature.

Bruno, G. V.; Harrington, J. K.; Eastman, M. P.

1978-01-01

109

Effect of different tumbling marination treatments on the quality characteristics of prepared pork chops.  

PubMed

The effect of different tumbling marination treatments (control group, CG; conventional static marination, SM; vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) on the quality characteristics of prepared pork chops was investigated under simulated commercial conditions. The CT treatment increased (p<0.05) the pH value, b* value, product yield, tenderness, overall flavor, sensory juiciness and overall acceptability in comparison to other treatments for prepared boneless pork chops. The CT treatment decreased (p<0.05) cooking loss, shear force value, hardness, gumminess and chewiness compared with other treatments. In addition, CT treatment effectively improved springiness and sensory color more than other treatments. However, IT treatment achieved the numerically highest (p<0.05) L* and a* values. These results suggested that CT treatment obtained the best quality characteristics of prepared pork chops and should be adopted as the optimal commercial processing method for this prepared boneless pork chops. PMID:25557823

Gao, Tian; Li, Jiaolong; Zhang, Lin; Jiang, Yun; Ma, Ruixue; Song, Lei; Gao, Feng; Zhou, Guanghong

2015-02-01

110

Effect of Different Tumbling Marination Treatments on the Quality Characteristics of Prepared Pork Chops  

PubMed Central

The effect of different tumbling marination treatments (control group, CG; conventional static marination, SM; vacuum continuous tumbling marination, CT; vacuum intermittent tumbling marination, IT) on the quality characteristics of prepared pork chops was investigated under simulated commercial conditions. The CT treatment increased (p<0.05) the pH value, b* value, product yield, tenderness, overall flavor, sensory juiciness and overall acceptability in comparison to other treatments for prepared boneless pork chops. The CT treatment decreased (p<0.05) cooking loss, shear force value, hardness, gumminess and chewiness compared with other treatments. In addition, CT treatment effectively improved springiness and sensory color more than other treatments. However, IT treatment achieved the numerically highest (p<0.05) L* and a* values. These results suggested that CT treatment obtained the best quality characteristics of prepared pork chops and should be adopted as the optimal commercial processing method for this prepared boneless pork chops. PMID:25557823

Gao, Tian; Li, Jiaolong; Zhang, Lin; Jiang, Yun; Ma, Ruixue; Song, Lei; Gao, Feng; Zhou, Guanghong

2015-01-01

111

Shuttle rendezvous radar performance evaluation and simulation  

NASA Technical Reports Server (NTRS)

The US Space Shuttle's Ku-band system was specifically designed for communications and tracking functions which are required during on-orbit operations with other spacecraft. Operating modes permit search and acquisition to be accomplished by computer designation or under manual control by the astronaut. Ku-band system data channels drive on-board dedicated displays and are incorporated into state vector updates by Shuttle guidance and navigation computers. Radar-cross-section estimates were used in computer simulations to predict the range at which radar detection and acquisition can be expected. Validity of the simulationi model and the radar design and performance were verified by flight tests on the White Sands test range. It is concluded that results of the testing established confidence in the capability of the system to provide the relative position and rate information which is needed for Shuttle work involving other spacecraft.

Griffin, John W.; Lindberg, Andrew C.; Ahn, Thomas B.; Harton, Paul L.

1988-01-01

112

Investigations of Tumbling Characteristics of a 1/20-Scale Model of the Northrop N-9M Airplane  

NASA Technical Reports Server (NTRS)

The tumbling characteristics of a 1/20-scale model of the Northrop N-9M airplane have been determined in the Langley 20-foot free-spinning tunnel for various configurations and loading conditions of the model. The investigation included tests to determine whether recovery from a tumble could be effected by the use of parachutes. An estimation of the forces due to acceleration acting on the pilot during a tumble was made. The tests were performed at an equivalent test altitude of 15,000 feet. The results of the model tests indicate that if the airplane is stalled with its nose up and near the vertical, or if an appreciable amount of pitching rotation is imparted to the airplane as through the action of a strong gust, the airplane will either tumble or oscillate in pitch through a range of angles of the order of +/-120 deg. The normal flying controls will probably be ineffective in preventing or in terminating the tumbling motion. The results of the model tests indicate that deflection of the landing flaps full down immediately upon the initiation of pitching rotation will tend to prevent the development of a state of tumbling equilibrium. The simultaneous opening of two-7-foot diameter parachutes having drag coefficients of 0.7, one parachute attached to the rear portion of each wing tip with a towline between 10 and 30 feet long, will provide recovery from a tumble. The accelerations acting on the pilot during a tumble will be dangerous.

MacDougall, George F., Jr.

1947-01-01

113

Determination of Eros Physical Parameters for Near Earth Asteroid Rendezvous Orbit Phase Navigation  

NASA Technical Reports Server (NTRS)

Navigation of the orbit phase of the Near Earth steroid Rendezvous (NEAR) mission will re,quire determination of certain physical parameters describing the size, shape, gravity field, attitude and inertial properties of Eros. Prior to launch, little was known about Eros except for its orbit which could be determined with high precision from ground based telescope observations. Radar bounce and light curve data provided a rough estimate of Eros shape and a fairly good estimate of the pole, prime meridian and spin rate. However, the determination of the NEAR spacecraft orbit requires a high precision model of Eros's physical parameters and the ground based data provides only marginal a priori information. Eros is the principal source of perturbations of the spacecraft's trajectory and the principal source of data for determining the orbit. The initial orbit determination strategy is therefore concerned with developing a precise model of Eros. The original plan for Eros orbital operations was to execute a series of rendezvous burns beginning on December 20,1998 and insert into a close Eros orbit in January 1999. As a result of an unplanned termination of the rendezvous burn on December 20, 1998, the NEAR spacecraft continued on its high velocity approach trajectory and passed within 3900 km of Eros on December 23, 1998. The planned rendezvous burn was delayed until January 3, 1999 which resulted in the spacecraft being placed on a trajectory that slowly returns to Eros with a subsequent delay of close Eros orbital operations until February 2001. The flyby of Eros provided a brief glimpse and allowed for a crude estimate of the pole, prime meridian and mass of Eros. More importantly for navigation, orbit determination software was executed in the landmark tracking mode to determine the spacecraft orbit and a preliminary shape and landmark data base has been obtained. The flyby also provided an opportunity to test orbit determination operational procedures that will be used in February of 2001. The initial attitude and spin rate of Eros, as well as estimates of reference landmark locations, are obtained from images of the asteroid. These initial estimates are used as a priori values for a more precise refinement of these parameters by the orbit determination software which combines optical measurements with Doppler tracking data to obtain solutions for the required parameters. As the spacecraft is maneuvered; closer to the asteroid, estimates of spacecraft state, asteroid attitude, solar pressure, landmark locations and Eros physical parameters including mass, moments of inertia and gravity harmonics are determined with increasing precision. The determination of the elements of the inertia tensor of the asteroid is critical to spacecraft orbit determination and prediction of the asteroid attitude. The moments of inertia about the principal axes are also of scientific interest since they provide some insight into the internal mass distribution. Determination of the principal axes moments of inertia will depend on observing free precession in the asteroid's attitude dynamics. Gravity harmonics are in themselves of interest to science. When compared with the asteroid shape, some insight may be obtained into Eros' internal structure. The location of the center of mass derived from the first degree harmonic coefficients give a direct indication of overall mass distribution. The second degree harmonic coefficients relate to the radial distribution of mass. Higher degree harmonics may be compared with surface features to gain additional insight into mass distribution. In this paper, estimates of Eros physical parameters obtained from the December 23,1998 flyby will be presented. This new knowledge will be applied to simplification of Eros orbital operations in February of 2001. The resulting revision to the orbit determination strategy will also be discussed.

Miller, J. K.; Antreasian, P. J.; Georgini, J.; Owen, W. M.; Williams, B. G.; Yeomans, D. K.

1995-01-01

114

Theory of Tumbling Bodies Entering Planetary Atmospheres with Application to Probe Vehicles and the Australian Tektites  

NASA Technical Reports Server (NTRS)

The tumbling motion of aerodynamically stable bodies entering planetary atmospheres is analyzed considering that the tumbling, its arrest, and the subsequent oscillatory motion are governed by the equation for the fifth Painleve' transcendent. Results based on the asymptotic behavior of the transcendent are applied to study (1) the oscillatory behavior of planetary probe vehicles in relation to aerodynamic heating and loads and (2) the dynamic behavior of the Australian tektites on entering the Earth's atmosphere, under the hypothesis that their origin was the Moon.

Tobak, Murray; Peterson, Victor L.

1964-01-01

115

Statistics of tumbling of a single polymer molecule in shear flow  

E-print Network

We present experimental results on statistics of polymer orientation angles relatively to shear plane and tumbling times in shear flow with thermal noise. Strong deviation of probability distribution functions (PDF) of these parameters from Gaussian was observed and a good accord with theory was found. The scaling relations of PDF widths for both angles as a function of the control parameter $Wi$ are verified and compared with numerics. An universal exponential PDF tail for the tumbling times and its predicted scaling with $Wi$ are also tested experimentally against numerics.

Sergiy Gerashchenko; Victor Steinberg

2005-03-11

116

Emergent Run-and-Tumble Behavior in a Simple Model of Chlamydomonas with Intrinsic Noise  

NASA Astrophysics Data System (ADS)

Recent experiments on the green alga Chlamydomonas that swims using synchronized beating of a pair of flagella have revealed that it exhibits a run-and-tumble behavior similar to that of bacteria such as E. coli. Using a simple purely hydrodynamic model that incorporates a stroke cycle and an intrinsic Gaussian white noise, we show that a stochastic run-and-tumble behavior could emerge due to the nonlinearity of the combined synchronization-rotation-translation dynamics. Our study suggests that nonlinear mechanics could be a significant contributing factor to how the trajectories of the microorganism are selected.

Bennett, Rachel R.; Golestanian, Ramin

2013-04-01

117

Effect of phosphate, ascorbic acid and ?-tocopherol injected at one-location with tumbling on quality of roast beef.  

PubMed

The purpose of this study was to evaluate if continuous non-vacuum or vacuum tumbling improves the quality of roast beef utilizing the one location injection. Basically, fresh roast beef treated by one location injection with tumbling had significantly different quality compared to non-tumbled ones. However, the cooked roast beef did not significantly exhibit better quality due to tumbling. There was insignificant difference of TBARS value for whole meat among treatments at day 0. The control had significantly higher TBARS value compared to roast beef with non-vacuum and vacuum tumbled samples at day 2. At 4, 7 and 14 days of refrigerated storage, the control maintained the significantly highest values when compared to the other treatments that had similar TBARS values. The addition of three antioxidants was the major contributor to lipid stability of the cooked roast beef. PMID:21075546

Cheng, Jen-Hua; Wang, Shu-Tai; Sun, Yi-Mei; Ockerman, Herbert W

2011-03-01

118

Effect of blade tenderization and tumbling time on the processing characteristics and tenderness of injected cooked roast beef.  

PubMed

The combined effect of blade tenderization (T, NT) and tumbling time (0, 2, 16 h) on quality characteristics of cooked beef roasts processed with 20 or 40% injection level was investigated. Properties of the beef roasts were determined by measuring processing and textural characteristics (shear force, texture profile analysis). Extended tumbling (to 16 h) favorably affected hydration properties and thermal stability, yielding lower cooking loss and purge and higher WHC for beef roasts. It also decreased shear force and hardness of beef samples by 50-60%, but was unable to increase cohesiveness. Blade tenderization prior to injection generally was found to be beneficial for textural characteristics, tended to improve cook yield, but did not influence other hydration properties. An interaction between tenderization and tumbling was observed for shear force. Blade tenderization decreased shear values by 15-20% for roasts tumbled for 0 or 2 h, but did not improve tenderness with extended tumbling. PMID:22061020

Pietrasik, Z; Shand, P J

2004-04-01

119

Autonomous control procedures for shuttle rendezvous proximity operations  

NASA Technical Reports Server (NTRS)

The results are presented of a study which uses fuzzy sets to model a Space Shuttle pilot's reasoning and actions while performing rendezvous proximity operation maneuvers. In this model fuzzy sets are used to simulate smooth and continuous actions as would be expected from an experienced pilot and to simulate common sense reasoning in the decision process. The present model assumes visual information available to the Shuttle pilot from the Shuttle Crew Optical Alignment Sighting (COAS) device and the overhead window and rendezvous radar sensor information available to him from an onboard display. This model will be used in a flight analysis simulator to perform studies requiring a large number of runs, each of which currently needs an engineer in the loop to supply the piloting decisions. This work has much broader implications in control of robots such as the Flight Telerobotic Servicer, in automated pilot control and attitude control, and in advisory and evaluation functions that could be used for flight data monitoring or for testing of various rule sets in flight preparation.

Lea, Robert N.; Mitchell, Eric V.; Goodwin, Mary Ann

1987-01-01

120

Gossip-based solutions for discrete rendezvous in populations of communicating agents.  

PubMed

The objective of the rendezvous problem is to construct a method that enables a population of agents to agree on a spatial (and possibly temporal) meeting location. We introduce the buffered gossip algorithm as a general solution to the rendezvous problem in a discrete domain with direct communication between decentralized agents. We compare the performance of the buffered gossip algorithm against the well known uniform gossip algorithm. We believe that a buffered solution is preferable to an unbuffered solution, such as the uniform gossip algorithm, because the use of a buffer allows an agent to use multiple information sources when determining its desired rendezvous point, and that access to multiple information sources may improve agent decision making by reinforcing or contradicting an initial choice. To show that the buffered gossip algorithm is an actual solution for the rendezvous problem, we construct a theoretical proof of convergence and derive the conditions under which the buffered gossip algorithm is guaranteed to produce a consensus on rendezvous location. We use these results to verify that the uniform gossip algorithm also solves the rendezvous problem. We then use a multi-agent simulation to conduct a series of simulation experiments to compare the performance between the buffered and uniform gossip algorithms. Our results suggest that the buffered gossip algorithm can solve the rendezvous problem faster than the uniform gossip algorithm; however, the relative performance between these two solutions depends on the specific constraints of the problem and the parameters of the buffered gossip algorithm. PMID:25397882

Hollander, Christopher D; Wu, Annie S

2014-01-01

121

Gossip-Based Solutions for Discrete Rendezvous in Populations of Communicating Agents  

PubMed Central

The objective of the rendezvous problem is to construct a method that enables a population of agents to agree on a spatial (and possibly temporal) meeting location. We introduce the buffered gossip algorithm as a general solution to the rendezvous problem in a discrete domain with direct communication between decentralized agents. We compare the performance of the buffered gossip algorithm against the well known uniform gossip algorithm. We believe that a buffered solution is preferable to an unbuffered solution, such as the uniform gossip algorithm, because the use of a buffer allows an agent to use multiple information sources when determining its desired rendezvous point, and that access to multiple information sources may improve agent decision making by reinforcing or contradicting an initial choice. To show that the buffered gossip algorithm is an actual solution for the rendezvous problem, we construct a theoretical proof of convergence and derive the conditions under which the buffered gossip algorithm is guaranteed to produce a consensus on rendezvous location. We use these results to verify that the uniform gossip algorithm also solves the rendezvous problem. We then use a multi-agent simulation to conduct a series of simulation experiments to compare the performance between the buffered and uniform gossip algorithms. Our results suggest that the buffered gossip algorithm can solve the rendezvous problem faster than the uniform gossip algorithm; however, the relative performance between these two solutions depends on the specific constraints of the problem and the parameters of the buffered gossip algorithm. PMID:25397882

Hollander, Christopher D.; Wu, Annie S.

2014-01-01

122

The Evolution of the Rendezvous Profile During the Space Shuttle Program  

NASA Technical Reports Server (NTRS)

The rendezvous and proximity operations approach design techniques for space shuttle missions has changed significantly during the life of the program in response to new requirements that were not part of the original mission design. The flexibility of the shuttle onboard systems design and the mission planning process has allowed the program to meet these requirements. The design of the space shuttle and the shift from docking to grappling with a robotic ann prevented use of legacy Apollo rendezvous techniques. Over the life of the shuttle program the rendezvous profile has evolved due to several factors, including lowering propellant consumption and increasing flexibility in mission planning. Many of the spacecraft that the shuttle rendezvoused with had unique requirements that drove the creation of mission-unique proximity operations. The dockings to the Russian Mir space station and International Space Station (ISS) required further evolution of rendezvous and proximity operations techniques and additional sensors to enhance crew situational awareness. After the Columbia accident, a Rendezvous Pitch Maneuver (RPM) was added to allow tile photography from ISS. Lessons learned from these rendezvous design changes are applicable to future vehicle designs and operations concepts.

Summa, William R.

2010-01-01

123

Is Father-Child Rough-and-Tumble Play Associated with Attachment or Activation Relationships?  

ERIC Educational Resources Information Center

The activation relationship theory, primarily focused on parental stimulation of risk-taking along with parental control during exploration, predicts that boys will be activated more than girls by their fathers. This theory may explain why fathers engage in rough-and-tumble play (RTP) with children more frequently than mothers, especially with…

Paquette, Daniel; Dumont, Caroline

2013-01-01

124

Practitioner Expertise: Creating Quality within the Daily Tumble of Events in Youth Settings  

ERIC Educational Resources Information Center

Practitioners in youth settings experience life on the ground as a tumble of events, shaped by a confluence of youth needs, institutional expectations, and other inputs. The quality of the setting is determined in part by practitioners' expertise in shaping and responding to these events. The situations that arise in practice, and how staff…

Larson, Reed W.; Rickman, Aimee N.; Gibbons, Colleen M.; Walker, Kathrin C.

2009-01-01

125

The Expression of Care in the Rough and Tumble Play of Boys.  

ERIC Educational Resources Information Center

Videotaped rough and tumble play to examine how preadolescent boys expressed care and intimacy through such play. Found that, when commenting on videotapes, the boys were clear on where and when it was appropriate to express care and intimacy for one another. Findings suggest teachers and administrators reconsider the importance of this kind of…

Reed, Tom; Brown, Mac

2000-01-01

126

Rough and Tumble Play Quality: Theoretical Foundations for a New Measure of Father-Child Interaction  

ERIC Educational Resources Information Center

Energetic, competitive, body-contact play (rough and tumble play (RTP)) is commonly observed among young children and is reported as an important feature of father-child relationships. Animal studies have demonstrated positive developmental effects of peer-peer play-wrestling, influencing cognitive and social outcomes. The purpose of this paper is…

Fletcher, Richard; StGeorge, Jennifer; Freeman, Emily

2013-01-01

127

A Two-Impulse Plan for Performing Rendezvous on a Once-A-Day Basis  

NASA Technical Reports Server (NTRS)

An investigation of a two-impulse plan for performing rendezvous on a once-a-day basis with a near-earth satellite station indicates that launch into rendezvous from slightly less than maximum satellite latitude is an unusually favorable circumstance in that no appreciable expense in mass ratio is incurred. In addition, it was found for the two-impulse maneuver employed in this study that the optimum angular travel of the ferry vehicle to rendezvous was considerably less than the 1800 transfer which is optimum for the two-impulse in-plane launch.

Bird, John D.; Thomas, David F., Jr.

1960-01-01

128

Stereoscopic multi-planar PIV measurements of in-cylinder tumbling flow  

NASA Astrophysics Data System (ADS)

The non-reacting flow field within the combustion chamber of a motored direct-injection spark-ignition engine with tumble intake port is measured. The three-dimensionality of the flow necessitates the measurement of all three velocity components via stereoscopic particle-image velocimetry in multiple planes. Phase-locked stereoscopic PIV is applied at 15 crank angles during the intake and compression strokes, showing the temporal evolution of the flow field. The flow fields are obtained within a set of 14 axial planes, covering nearly the complete cylinder volume. The stereoscopic PIV setup applied to engine in-cylinder flow and the arising problems and solutions are discussed in detail. The three-dimensional flow field is reconstructed and analyzed using vortex criteria. The tumble vortex is the dominant flow structure, and this vortex varies significantly regarding shape, strength, and position throughout the two strokes. The tumble vortex center moves clockwise through the combustion chamber. At first, the tumble has a c-shape which turns into an almost straight tube at the end of the compression. Small-scale structures are analyzed by the distribution of the turbulent kinetic energy. It is evident that the symmetry plane only represents the 3D flow field after 100 CAD. For earlier crank angles, both kinetic energy (KE) and turbulent kinetic energy (TKE) in the combustion chamber are well below the KE and TKE in the symmetry plane. This should be taken into account when the injection and breakup of the three-dimensional fuel jet are studied. The mean kinetic energy is conserved until late compression by the tumble motion. This conservation ensures through the excited air motion an enhancement of the initial air-fuel mixture which is of interest for direct-injection gasoline engines.

Bücker, I.; Karhoff, D.-C.; Klaas, M.; Schröder, W.

2012-12-01

129

Some impulsive rendezvous trajectories and their possible optimality.  

NASA Technical Reports Server (NTRS)

Two- and three-impulse trajectories are investigated for fixed-time, fixed-angle rendezvous between vacant circular coplanar orbits, for trip angles less than, or equal to 2 pi in magnitude. For two-impulse trajectories, general features of the characteristic velocity function are outlined. Parameters of the intermediate orbit are reviewed. Attention is given to limiting cases. Computation of the adjoint system helps to define the domain of possible optimality foajectories: it is a closed domain in the trip time, trip angle plane. Waiting periods on terminal orbits are considered. The domain of possible optimality is defined using Lawden's primer vrtory. This domain extends to infinity if the radius ratio of terminal orbits is less than 15.6. Three-impulse trajectories are tried in cases where two-impulse trajectories, with or without cost, have been found nonoptimal. Improvements on the characteristic velocity are thus obtained.

Peltier, J. P.

1972-01-01

130

Rendezvous, proximity operations and capture quality function deployment report  

NASA Technical Reports Server (NTRS)

Rendezvous, Proximity Operations, and Capture (RPOC) is a missions operations area which is extremely important to present and future space initiatives and must be well planned and coordinated. To support this, a study team was formed to identify a specific plan of action using the Quality Function Deployment (QFD) process. This team was composed of members from a wide spectrum of engineering and operations organizations which are involved in the RPOC technology area. The key to this study's success is an understanding of the needs of potential programmatic customers and the technology base available for system implementation. To this end, the study team conducted interviews with a variety of near term and future programmatic customers and technology development sponsors. The QFD activity led to a thorough understanding of the needs of these customers in the RPOC area, as well as the relative importance of these needs.

Lamkin, Stephen L. (editor)

1991-01-01

131

Single photon lidar demonstrator for asteroid rendezvous missions  

NASA Astrophysics Data System (ADS)

We present compact single photon lidar demonstrator dedicated for asteroid rendezvous missions. The instrument provides crucial data on altitude and terrain profile for altitudes exceeding 5km with a precision of less than 10 cm fulfilling the Rayleigh criterion. Transmitter and receiver optics designs are discussed, control and processing electronics based on a single rad-hard compatible FPGA (Field Programmable Gate Array) is analyzed. The FPGA electronics subsystems are TDC (Time-to-Digit Converter), laser trigger pulse generator and gate generator. Indoor calibration procedures of the whole demonstrator chain are proposed and evaluated. The calibration covers positioning of receiver and transmitter optics related to detector and laser, aligning of transmitter and receiver optical common paths. The retrieving strategy of terrain elevation profile is proposed and via indoor tests validated. Theory for surface slope and scanning is established, simulation and measurement results are compared and discussed.

Vacek, Michael; Michalek, Vojtech; Peca, Marek; Prochazka, Ivan; Blazej, Josef; Djurovic, Goran

2015-01-01

132

Rendezvous Integration Complexities of NASA Human Flight Vehicles  

NASA Technical Reports Server (NTRS)

Propellant-optimal trajectories, relative sensors and navigation, and docking/capture mechanisms are rendezvous disciplines that receive much attention in the technical literature. However, other areas must be considered. These include absolute navigation, maneuver targeting, attitude control, power generation, software development and verification, redundancy management, thermal control, avionics integration, robotics, communications, lighting, human factors, crew timeline, procedure development, orbital debris risk mitigation, structures, plume impingement, logistics, and in some cases extravehicular activity. While current and future spaceflight programs will introduce new technologies and operations concepts, the complexity of integrating multiple systems on multiple spacecraft will remain. The systems integration task may become more difficult as increasingly complex software is used to meet current and future automation, autonomy, and robotic operation requirements.

Brazzel, Jack P.; Goodman, John L.

2009-01-01

133

A Comparison Between Orion Automated and Space Shuttle Rendezvous Techniques  

NASA Technical Reports Server (NTRS)

The Orion spacecraft will replace the space shuttle and will be the first human spacecraft since the Apollo program to leave low earth orbit. This vehicle will serve as the cornerstone of a complete space transportation system with a myriad of mission requirements necessitating rendezvous to multiple vehicles in earth orbit, around the moon and eventually beyond . These goals will require a complex and robust vehicle that is, significantly different from both the space shuttle and the command module of the Apollo program. Historically, orbit operations have been accomplished with heavy reliance on ground support and manual crew reconfiguration and monitoring. One major difference with Orion is that automation will be incorporated as a key element of the man-vehicle system. The automated system will consist of software devoted to transitioning between events based on a master timeline. This effectively adds a layer of high level sequencing that moves control of the vehicle from one phase to the next. This type of automated control is not entirely new to spacecraft since the shuttle uses a version of this during ascent and entry operations. During shuttle orbit operations however many of the software modes and hardware switches must be manually configured through the use of printed procedures and instructions voiced from the ground. The goal of the automation scheme on Orion is to extend high level automation to all flight phases. The move towards automation represents a large shift from current space shuttle operations, and so these new systems will be adopted gradually via various safeguards. These include features such as authority-to-proceed, manual down modes, and functional inhibits. This paper describes the contrast between the manual and ground approach of the space shuttle and the proposed automation of the Orion vehicle. I will introduce typical orbit operations that are common to all rendezvous missions and go on to describe the current Orion automation architecture and contrast it with shuttle rendezvous techniques and circumstances. The shuttle rendezvous profile is timed to take approximately 3 days from orbit insertion to docking at the International Space Station (ISS). This process can be divided into 3 phases: far-field, mid-field and proximity operations. The far-field stage is characterized as the most quiescent phase. The spacecraft is usually too far to navigate using relative sensors and uses the Inertial Measurement Units (IMU s) to numerically solve for its position. The maneuvers are infrequent, roughly twice per day, and are larger than other burns in the profile. The shuttle uses this opportunity to take extensive ground based radar updates and keep high fidelity orbit states on the ground. This state is then periodically uplinked to the shuttle computers. The targeting solutions for burn maneuvers are also computed on the ground and uplinked. During the burn the crew is responsible for setting the shuttle attitude and configuring the propulsion system for ignition. Again this entire process is manually driven by both crew and ground activity. The only automatic processes that occur are associated with the real-time execution of the burn. The Orion automated functionality will seek to relieve the workload of both the crew and ground during this phase

Ruiz, Jose O,; Hart, Jeremy

2010-01-01

134

Orion Rendezvous, Proximity Operations, and Docking Design and Analysis  

NASA Technical Reports Server (NTRS)

The Orion vehicle will be required to perform rendezvous, proximity operations, and docking with the International Space Station (ISS) and the Earth Departure Stage (EDS)/Lunar Landing Vehicle (LLV) stack in Low Earth Orbit (LEO) as well as with the Lunar Landing Vehicle in Low Lunar Orbit (LLO). The RPOD system, which consists of sensors, actuators, and software is being designed to be flexible and robust enough to perform RPOD with different vehicles in different environments. This paper will describe the design and the analysis which has been performed to date to allow the vehicle to perform its mission. Since the RPOD design touches on many areas such as sensors selection and placement, trajectory design, navigation performance, and effector performance, it is inherently a systems design problem. This paper will address each of these issues in order to demonstrate how the Orion RPOD has been designed to accommodate and meet all the requirements levied on the system.

D'Souza, Christopher; Hanak, F. Chad; Spehar, Pete; Clark, Fred D.; Jackson, Mark

2007-01-01

135

Mission opportunity maps for rendezvous with earth-crossing asteroids  

NASA Technical Reports Server (NTRS)

Rendezvous missions to earth-crossing asteroids are of interest to NASA, for scientific purposes as well as for technological applications and ecological implications. To provide a comprehensive data base for planners of such missions, a mission opportunity map (MOM) has been created for eight relatively easy-to-access asteroids. A MOM presents such mission data as launch dates, flight times, and launch and postlaunch delta V requirements for all useful mission opportunities. The merits of a MOM are: (1) searches for all useful mission oportunities are completed in the process of generating a MOM, and (2) a MOM provides a clear view of good and bad opportunities, the extent of performance variations, and the repeatability of the missions.

Yen, Chen-Wan L.

1989-01-01

136

Rendezvous, proximity operations and capture quality function deployment report  

NASA Astrophysics Data System (ADS)

Rendezvous, Proximity Operations, and Capture (RPOC) is a missions operations area which is extremely important to present and future space initiatives and must be well planned and coordinated. To support this, a study team was formed to identify a specific plan of action using the Quality Function Deployment (QFD) process. This team was composed of members from a wide spectrum of engineering and operations organizations which are involved in the RPOC technology area. The key to this study's success is an understanding of the needs of potential programmatic customers and the technology base available for system implementation. To this end, the study team conducted interviews with a variety of near term and future programmatic customers and technology development sponsors. The QFD activity led to a thorough understanding of the needs of these customers in the RPOC area, as well as the relative importance of these needs.

Lamkin, Stephen L.

1991-12-01

137

Deep Interior: Multiple-Rendezvous Prospecting of NEOs  

NASA Astrophysics Data System (ADS)

This is an international multiple-rendezvous mission designed to prospect the deep interior and subsurface geophysical properties of diverse near-Earth objects, using reflection radar tomography, imaging, gravity, and explosions. What we learn will greatly influence future missions and guide strategies for the diversion, disruption, or utilization of potentially hazardous objects. Deep Interior. Low-frequency radar to determine internal variations of complex permittivity at resolutions approaching 20 m. Map inclusions or voids, fracture geometries, and compositional or structural boundaries. Subsurface. High-frequency radar to determine depth of regolith, existence and nature of cometary mantle, geology beneath and around craters, and subsurface expressions to surface geology. Topography and Geodesy. Stereogrammetric imaging with 1 m/pixel spatial resolution, supplemented by radar altimetry in shadowed regions, to determine detailed shape, volume, and spin state. Compare with radar sounding to learn how internal structure is manifested on the surface. Mass and Density. Total mass and lower moments of the internal mass distribution by mapping the exterior gravitational field. Look for mass concentrations. Surface microphysics and composition. Map color, albedo, and scattering properties of the surface over sunlit regions in six optical filters. Material properties. Deploy grenades to characterize the mechanics and dynamics of surface materials. Record 8 frame/sec, 20 cm/pixel videos of crater formation and ejecta dynamics, to enable simple and direct laboratory constraints on material density, cohesion and porosity. Dust. Look for dust lofted by surface waves propagating from the explosions, to constrain elastic properties and attenuation. Observe longer-term dynamics and optical properties of dust "atmosphere" generated by human activity. Cometary Activity. At comet 107P/Wilson-Harrington, look for expressions of past cometary activity, and for possible awakening from dormancy by explosions. NEO Diversity. Assess the diversity of the interior structures in two classes of near-Earth objects. New Technology. SEP, first multiple rendezvous, autonav, first grenades. Precursor to geoseismic investigations.

Kakuda, R. Y.; Asphaug, E.; Belton, M. J. S.; Gulkis, S.; Huebner, W. F.

2000-10-01

138

Avionics and control system development for mid-air rendezvous of two unmanned aerial vehicles  

E-print Network

A flight control system was developed to achieve mid-air rendezvous of two unmanned aerial vehicles (UAVs) as a part of the Parent Child Unmanned Aerial Vehicle (PCUAV) project at MIT and the Draper Laboratory. A lateral ...

Park, Sanghyuk, 1973-

2004-01-01

139

An application of linear covariance analysis to the design of responsive near-rendezvous missions  

E-print Network

This thesis investigates a new class of launch vehicles capable of being released from an aircraft which ultimately have the goal of achieving near-rendezvous conditions at orbital altitudes up to 800 km. These launch ...

Visser, Benjamin Lee

2007-01-01

140

Rendezvous-Guidance Trajectory Planning for Robotic Dynamic Obstacle Avoidance and Interception  

Microsoft Academic Search

This correspondence presents a novel online trajectory-planning method for the autonomous robotic interception of moving targets in the presence of dynamic obstacles, i.e., position and velocity matching (also referred to as rendezvous). The proposed time-optimal interception method is a hybrid algorithm that augments a novel rendezvous-guidance (RG) technique with the velocity-obstacle approach, for obstacle avoidance, first reported by Fiorini and

Faraz Kunwar; Beno Benhabib

2006-01-01

141

Description of the rendezvous experiment designed for 2007 Mars Premier mission  

NASA Technical Reports Server (NTRS)

The Mars Premier mission that was to be flown in 2007 by CNES in cooperation with NASA/JPL included a rendezvous experiment to be performed in Mars orbit to validate key technologies applicable to a Sample Return mission. The experiment goal was to demonstrate the capability to detect and track a sample canister at long range and validate terminal rendezvous strategies including a capture.

Delpech, M.; Dubois, J. B.; Riedel, J. E.; Guinn, J. R.

2003-01-01

142

Fault tolerant cooperative control for UAV rendezvous problem subject to actuator faults  

NASA Astrophysics Data System (ADS)

This paper investigates the problem of fault tolerant cooperative control for UAV rendezvous problem in which multiple UAVs are required to arrive at their designated target despite presence of a fault in the thruster of any UAV. An integrated hierarchical scheme is proposed and developed that consists of a cooperative rendezvous planning algorithm at the team level and a nonlinear fault detection and isolation (FDI) subsystem at individual UAV's actuator/sensor level. Furthermore, a rendezvous re-planning strategy is developed that interfaces the rendezvous planning algorithm with the low-level FDI. A nonlinear geometric approach is used for the FDI subsystem that can detect and isolate faults in various UAV actuators including thrusters and control surfaces. The developed scheme is implemented for a rendezvous scenario with three Aerosonde UAVs, a single target, and presence of a priori known threats. Simulation results reveal the effectiveness of our proposed scheme in fulfilling the rendezvous mission objective that is specified as a successful intercept of Aerosondes at their designated target, despite the presence of severe loss of effectiveness in Aerosondes engine thrusters.

Jiang, T.; Meskin, N.; Sobhani-Tehrani, E.; Khorasani, K.; Rabbath, C. A.

2007-04-01

143

Selection of rendezvous sites and reuse of pup raising areas among wolves Canis lupus of north-eastern Apennines, Italy  

Microsoft Academic Search

A coarse scale analysis was carried out of factors affecting rendezvous site selection and fidelity to pup raising areas in\\u000a wolfCanis lupus Linnaeus, 1758 packs inhabiting the north eastern Apennines, Italy. From 1993 to 2004, 44 rendezvous sites were identified,\\u000a and compared with random sites for variables related to topography, habitat, and human presence. Rendezvous sites were significantly\\u000a more frequent

Claudia Capitani; Luca Mattioli; Elisa Avanzinelli; Andrea Gazzola; Paolo Lamberti; Lorenza Mauri; Massimo Scandura; Alessia Viviani; Marco Apollonio

2006-01-01

144

Electron paramagnetic resonance studies of slowly tumbling vanadyl spin probes in nematic liquid crystals  

NASA Technical Reports Server (NTRS)

The purposes of this vanadyl spin probe study are threefold: (1) to establish when the breakdown of motionally narrowed formulas occurs; (2) to analyze the experimental vanadyl EPR line shapes by the stochastic Lioville method as developed by Polnaszek et al. (1973) for slow tumbling in an anisotropic liquid; and (3) to compare the vanadyl probe study results with those of Polnaszek and Freed (1975). Spectral EPR line shapes are simulated for experimental spectra of vanadyl acetylacetonate (VOAA) in nematic liquid crystal butyl p-(p-ethoxyphenoxycarbonyl) phenyl carbonate (BEPC) and Phase V of EM laboratories. It is shown that the use of typical vanadyl complexes as spin probes for nematic liquid crystals simplifies the theoretical analysis and the subsequent interpretation. Guidelines for the breakdown of motionally narrowed formulas are established. Both the slow tumbling aspects and the effects of non-Brownian rotation should be resolved in order to extract quantitative information about molecular ordering and rotational mobility.

Bruno, G. V.; Harrington, J. K.; Eastman, M. P.

1978-01-01

145

Hubble Servicing Challenges Drive Innovation of Shuttle Rendezvous Techniques  

NASA Technical Reports Server (NTRS)

Hubble Space Telescope (HST) servicing, performed by Space Shuttle crews, has contributed to what is arguably one of the most successful astronomy missions ever flown. Both nominal and contingency proximity operations techniques were developed to enable successful servicing, while lowering the risk of damage to HST systems, and improve crew safety. Influencing the development of these techniques were the challenges presented by plume impingement and HST performance anomalies. The design of both the HST and the Space Shuttle was completed before the potential of HST contamination and structural damage by shuttle RCS jet plume impingement was fully understood. Relative navigation during proximity operations has been challenging, as HST was not equipped with relative navigation aids. Since HST reached orbit in 1990, proximity operations design for servicing missions has evolved as insight into plume contamination and dynamic pressure has improved and new relative navigation tools have become available. Servicing missions have provided NASA with opportunities to gain insight into servicing mission design and development of nominal and contingency procedures. The HST servicing experiences and lessons learned are applicable to other programs that perform on-orbit servicing and rendezvous, both human and robotic.

Goodman, John L.; Walker, Stephen R.

2009-01-01

146

Ku-Band rendezvous radar performance computer simulation model  

NASA Technical Reports Server (NTRS)

All work performed on the Ku-band rendezvous radar performance computer simulation model program since the release of the preliminary final report is summarized. Developments on the program fall into three distinct categories: (1) modifications to the existing Ku-band radar tracking performance computer model; (2) the addition of a highly accurate, nonrealtime search and acquisition performance computer model to the total software package developed on this program; and (3) development of radar cross section (RCS) computation models for three additional satellites. All changes in the tracking model involved improvements in the automatic gain control (AGC) and the radar signal strength (RSS) computer models. Although the search and acquisition computer models were developed under the auspices of the Hughes Aircraft Company Ku-Band Integrated Radar and Communications Subsystem program office, they have been supplied to NASA as part of the Ku-band radar performance comuter model package. Their purpose is to predict Ku-band acquisition performance for specific satellite targets on specific missions. The RCS models were developed for three satellites: the Long Duration Exposure Facility (LDEF) spacecraft, the Solar Maximum Mission (SMM) spacecraft, and the Space Telescopes.

Magnusson, H. G.; Goff, M. F.

1984-01-01

147

The effects of low salt concentrations on the mechanism of adhesion between two pieces of pork semimembranosus muscle following tumbling and cooking.  

PubMed

The aim of this research was to gain deeper insight into the effect of salt content on the adhesion between pieces of semimembranosus pork muscle bound by a tumbling exudate gel. Hydrophobic site number, free thiol and carbonyl content were measured in tumbling exudate and meat protein to evaluate the protein-protein interactions involved in the adhesion process. Proteins were far more oxidized in exudate than in meat, and under our experimental conditions, salt content increased protein bonding in the exudate but not in the meat. Breaking stress increased between non-salted meat and 0.8%-salted meat but did not depend on the protein physicochemical properties of the tumbling exudate. Modifying the meat surface by tumbling alone, tumbling and salting, or scarification had no effect on breaking stress. It is suggested that the break between the meat pieces occurred between the tumbling exudate and the meat surface due to weaker chemical bonds at this location. PMID:23896131

Bombrun, Laure; Gatellier, Philippe; Carlier, Martine; Kondjoyan, Alain

2014-01-01

148

Space shuttle Ku-band integrated rendezvous radar/communications system study  

NASA Technical Reports Server (NTRS)

The results are presented of work performed on the Space Shuttle Ku-Band Integrated Rendezvous Radar/Communications System Study. The recommendations and conclusions are included as well as the details explaining the results. The requirements upon which the study was based are presented along with the predicted performance of the recommended system configuration. In addition, shuttle orbiter vehicle constraints (e.g., size, weight, power, stowage space) are discussed. The tradeoffs considered and the operation of the recommended configuration are described for an optimized, integrated Ku-band radar/communications system. Basic system tradeoffs, communication design, radar design, antenna tradeoffs, antenna gimbal and drive design, antenna servo design, and deployed assembly packaging design are discussed. The communications and radar performance analyses necessary to support the system design effort are presented. Detailed derivations of the communications thermal noise error, the radar range, range rate, and angle tracking errors, and the communications transmitter distortion parameter effect on crosstalk between the unbalanced quadriphase signals are included.

1976-01-01

149

Tumbling experiments to test fragmentation and abrasion of rocks from the Southern Alps, New Zealand  

NASA Astrophysics Data System (ADS)

Detrital cobbles and pebbles were collected from rivers draining the Southern Alps in the South Island of New Zealand. Our objective was to obtain a time-series of abrasion and fragmentation processes, in order to replicate fluvial processes and understand the relative erosion resistance of bedrock lithologies. Lithologies included variably metamorphosed greywacke-sandstone, semischist and schist, reflecting the range of rocks in the hangingwall of the Alpine Fault exhumed by differential uplift, and granite and gneiss in the footwall. Rocks were cut into 3cm cubes, weighed individually and washed in millipore water, then photographed. Experimental sample sets, matching the proportions of rock lithologies observed in the riverbeds, were placed in rectangular 20 litre containers together with 2 litres of fresh rainwater. Containers were rotated in a concrete mixer at 26 revolutions per minute for 2, 4, 12 and 49 hours, with a duplicate geochemical blank sample left for 50 hrs without tumbing. Each set of tumbled material was then extracted, photographed, classified, sorted into size fractions, weighed and saved for further analysis. Samples of sand, silt, rock-contaminated water and suspended sediment were also collected for filtering of suspended sediment, petrography and chemical analysis. Tumbling produced dramatic differences in the behaviour of different rocks, particularly in the relative strength of sandstone, semischist and schist lithologies. Cubes of schist fragmented into tabular pieces and rounded quickly, within two hours, compared with semischist and sandstone which retained cuboid forms and suffered only minor rounding of edges after 49 hours tumbling. Fine-grained material produced as a by-product was dominated by a silt/clay fraction that increased in quantity with tumbling time. Relatively little sand-sized sediment was generated, and its quantity decreased with tumbling time as it was also transformed into finer material. The experiment highlights a difference in the dominant mechanisms by which the various rock lithologies present in the Southern Alps of New Zealand reduce their size, replicating transport in a fluvial system. Schists reduce their grain size by relatively rapid disaggregation, whereas greywacke and semischist are more prone to abrasion. The simple experiment has relatively important message for studies of erosion from mountain catchments based on detrital sediments. We conclude that suspended and bedload in the Southern Alps rivers can be expected to be heavily biased by the input of schist, which might be the case for other mountain ranges. Studies of sediment provenance require experimental results such as these.

Herman, F.; Fluekiger, L.; Cox, S. C.; Beyssac, O.

2011-12-01

150

An Automatic Terminal Guidance System for Rendezvous with a Satellite  

NASA Technical Reports Server (NTRS)

This study includes a consideration of the design philosophy for an automatic terminal guidance system, a derivation of guidance equations required, and an outline of the general type of instrumentation necessary to provide the essential information. A control system for a sample vehicle is analyzed. A representative case, rendezvous with a satellite in circular orbit at 400 nautical miles, was examined. Terminal-stage nominal burning times of 200 and 400 seconds were used. For the 200-second case, initial errors in circumferential displacement of +/- 25,000 feet, in radial displacement of 7,000 to -9,000 feet, and in lateral displacement of +/- 20,000 feet were within the capabilities of the system. Velocity errors of 300 to -400 ft/sec in the circumferential direction, 180 to -200 ft/sec in the radial direction, and velocity offsets of at least 20 (+/- 800 ft/sec) in the lateral direction could also be handled. The 400-second case was capable of correcting larger errors, but limits were not determined. The dependence of required characteristic velocity on initial errors was determined and it was found that increases over the nominal terminal-stage characteristic velocity of the order of 15 percent covered most of the previously mentioned in-plane errors. The requirements were more severe for cases with lateral velocity offsets. A simplified set of guidance equations was tested and produced only slight variations in performance. Overall velocity requirements and mass ratios were determined for terminal-stage burning times of 100, 200, 300, and 400 seconds and for a range of transfer angles by using exact calculations for the terminal stage and an impulsive launching velocity. These results indicated that the shortest burning time consistent with the launch guidance errors expected gave the best mass ratio.

Carney, Terrance M.

1961-01-01

151

Robust rendezvous maneuver point conditions. M.S. Thesis - Massachusetts Inst. of Tech.  

NASA Technical Reports Server (NTRS)

This study develops rendezvous maneuver point conditions that are robust to one dimensional errors in state estimation and burn execution. Allowing small deviations in the time of intercept provides a degree of freedom that can be used to compensate for these errors. The direction of allowable burn deviation is developed for errors in state estimation and burn execution. The maneuver points for which the error is aligned with the insensitive direction provide excellent rendezvous initiation points. The method is applied to sample rendezvous for vehicles in circular and elliptic orbits. Robust maneuver points are selected and the vehicles' relative motion plotted, demonstrating the validity of the maneuver points. Finally, a graphical illustration of the error focusing effect is demonstrated by means of a Monte Carlo simulation.

Fogle, Debra Ann

1992-01-01

152

Interesting rendezvous location in a liver transplantation patient with anastomosis stricture  

PubMed Central

An endoscopic or radiologic percutaneous approach may be an initial minimally invasive method for treating biliary strictures after living donor liver transplantation; however, cannulation of biliary strictures is sometimes difficult due to the presence of a sharp or twisted angle within the stricture or a complete stricture. When an angulated or twisted biliary stricture interrupts passage of a guidewire over the stricture, it is difficult to replace the percutaneous biliary drainage catheter with inside stents by endoscopic retrograde cholangiopancreatography. The rendezvous technique can be used to overcome this difficulty. In addition to the classical rendezvous method, in cases with complete transection of the common bile duct a modified technique involving the insertion of a snare into the subhepatic space has been successfully performed. Herein, we report a modified rendezvous technique in the duodenal bulb as an extraordinary location for a patient with duct-to-duct anastomotic complete stricture after liver transplantation. PMID:25400478

Odemis, Bulent; Oztas, Erkin; Yurdakul, Mehmet; Torun, Serkan; Suna, Nuredtin; Kayacetin, Ertugrul

2014-01-01

153

An Assessment of the Technology of Automated Rendezvous and Capture in Space  

NASA Technical Reports Server (NTRS)

This paper presents the results of a study to assess the technology of automated rendezvous and capture (AR&C) in space. The outline of the paper is as follows. First, the history of manual and automated rendezvous and capture and rendezvous and dock is presented. Next, the need for AR&C in space is established. Then, today's technology and ongoing technology efforts related to AR&C in space are reviewed. In light of these, AR&C systems are proposed that meet NASA's future needs, but can be developed in a reasonable amount of time with a reasonable amount of money. Technology plans for developing these systems are presented; cost and schedule are included.

Polites, M. E.

1998-01-01

154

Interesting rendezvous location in a liver transplantation patient with anastomosis stricture.  

PubMed

An endoscopic or radiologic percutaneous approach may be an initial minimally invasive method for treating biliary strictures after living donor liver transplantation; however, cannulation of biliary strictures is sometimes difficult due to the presence of a sharp or twisted angle within the stricture or a complete stricture. When an angulated or twisted biliary stricture interrupts passage of a guidewire over the stricture, it is difficult to replace the percutaneous biliary drainage catheter with inside stents by endoscopic retrograde cholangiopancreatography. The rendezvous technique can be used to overcome this difficulty. In addition to the classical rendezvous method, in cases with complete transection of the common bile duct a modified technique involving the insertion of a snare into the subhepatic space has been successfully performed. Herein, we report a modified rendezvous technique in the duodenal bulb as an extraordinary location for a patient with duct-to-duct anastomotic complete stricture after liver transplantation. PMID:25400478

Odemis, Bulent; Oztas, Erkin; Yurdakul, Mehmet; Torun, Serkan; Suna, Nuredtin; Kayacetin, Ertugrul

2014-11-14

155

Compressing an Elliptic Vortex: Transition to Turbulence by Tumble Breakdown  

NASA Technical Reports Server (NTRS)

Stability of the elliptic vortex attracted interest in the past decade. Cambon (1982), and Cambon, Teissedre and Jeandel (1985) have studied the stability of such flows with spatially uniform velocity gradient, and have provided RDT solutions for a wide range of the parameter S/Omega (where the strain rate S and the vorticity 2 Omega define the velocity gradient matrix). The range studied included those of hyperbolic streamlines (strain dominated, S/Omega is greater than 1), linear streamlines (simple shear, S/Omega = 1), and elliptical streamlines (vorticity dominated, S/Omega is less than 1). The latter class has more recently attracted interest and several studies appeared (Pierrehumbert 1986, Bayly 1986, Craik and Criminale 1986). These studies will be collectively referred to as PBCC.

Godeferd, Fabien S.; Mansour, Nagi N.; Cambon, Claude

1996-01-01

156

A Time and Place for Everything: A Discrete Systems Perspective on the Role of Children's Rough-and-Tumble Play in Educational Settings.  

ERIC Educational Resources Information Center

Notes that rough-and-tumble play must be considered in the context of social values; has beneficial influences on children's cognitive and social development; and is distinguishable from aggression. Makes a case for the use of socializing techniques in conjunction with rough and tumble play. (LB)

MacDonald, Kevin

1992-01-01

157

Prediction of flow-aligning and tumbling in a bent-core nematic liquid crystal using measurements of orienation order parameters  

NASA Astrophysics Data System (ADS)

The flow behavior of bent-core nematic liquid crystal (A131), which has been known to exhibit a biaxial nematic phase, is predicted by measurements of 2^nd and 4^th rank orientation order parameters. Using experimentally determined uniaxial, and , and biaxial orientation order parameters, , and from polarized micro-Raman spectroscopy, we compute the tumbling parameter, ?. The relationships between the order parameters and tumbling parameter derived by 2 different groups are used and the results are computed: a molecular theory by Archer and Larson (1995), that by Kroger and Seller (1995) for uniaxial system, and Leslie's theory for 2-director continuum. Temperature evolution of tumbling parameter shows the transition from a flow alignment regime to a tumbling instability. The results of the temperature evolution of tumbling parameter of bent-core nematic LC are compared to those of pure nematic LC (5CB) and LC mixture (E7).

Park, Min Sang; Park, Beom-Jin; Park, Jung Ok; Srinivasarao, Mohan

2010-03-01

158

Sensory fusion for planetary surface robotic navigation, rendezvous, and manipulation operations  

NASA Technical Reports Server (NTRS)

This paper reports some of the ongoing work at JPL in the areas of autonomous sensory fusion of both raw and derived inputs for better localization during long traverses, precision rendezvous operations with both labeled and unlabeled targets, and precision manipulation of targets.

Huntsberger, T.; Cheng, Y.; Baumgartner, E. T.; Robinson, M.; Schenker, P. S.

2003-01-01

159

On-Line Robotic Interception Planning Using a Rendezvous-Guidance Technique  

Microsoft Academic Search

A novel method for online, robotic interception of moving objects using visual feedback is proposed in this paper. No prior knowledge of the motion of the object is assumed. Since such objects might depart quickly from the workspace of the robot, fast interception is a critical issue. Thus, a novel time-optimal rendezvous-guidance technique that takes the dynamic limitations of the

Farhad Agah; Mehran Mehrandezh; Robert G. Fenton; Beno Benhabib

2004-01-01

160

STELLAR Alpine Rendez-Vous White Paper Workshop 6: dataTEL -Datasets for Technology Enhanced  

E-print Network

STELLAR Alpine Rendez-Vous White Paper Workshop 6: dataTEL - Datasets for Technology Enhanced (LMU Munich, DE) powered by hal-00722845,version1-5Aug2012 #12;STELLAR White Paper dataTEL - Datasets by the issue that very less educational datasets are publicly available in TEL, so that the outcomes

Paris-Sud XI, Université de

161

Proximity Operations for Space Situational Awareness Spacecraft Rendezvous and Maneuvering using Numerical Simulations and Fuzzy Logic  

Microsoft Academic Search

The authors present several spacecraft rendezvous and close proximity maneuvering techniques modeled with a high-precision numerical integrator using full force models and closed loop control with a Fuzzy Logic intelligent controller to command the engines. The authors document and compare the maneuvers, fuel use, and other parameters. This paper presents an innovative application of an existing capability to design, simulate

Timothy Carrico; T. Langster; J. Carrico; S. Alfano; M. Loucks; D. Vallado

2006-01-01

162

Charlie Chan: The Untold Story of the Honorable Detective and His Rendezvous with American History  

E-print Network

1 Charlie Chan: The Untold Story of the Honorable Detective and His Rendezvous with American." --Pico Iyer, Time In one of the most celebrated books of the year, comes this first biography of Charlie as a literary sleuth and Hollywood film icon. Finally resurrecting Charlie Chan from the graveyard of detested

Danforth, Bryan Nicholas

163

Robust rendezvous for mobile autonomous agents via proximity graphs in arbitrary dimensions  

Microsoft Academic Search

This paper presents coordination algorithms for networks of mobile autonomous agents. The objective of the proposed algorithms is to achieve rendezvous, that is, agreement over the location of the agents in the network. We provide analysis and design results for multiagent networks in arbitrary dimensions under weak requirements on the switching and failing communication topology. The novel correctness proof relies

Jorge Cortes; Sonia Martínez; Francesco Bullo

2006-01-01

164

Methodology for Prototyping Increased Levels of Automation for Spacecraft Rendezvous Functions  

NASA Technical Reports Server (NTRS)

The Crew Exploration Vehicle necessitates higher levels of automation than previous NASA vehicles, due to program requirements for automation, including Automated Rendezvous and Docking. Studies of spacecraft development often point to the locus of decision-making authority between humans and computers (i.e. automation) as a prime driver for cost, safety, and mission success. Therefore, a critical component in the Crew Exploration Vehicle development is the determination of the correct level of automation. To identify the appropriate levels of automation and autonomy to design into a human space flight vehicle, NASA has created the Function-specific Level of Autonomy and Automation Tool. This paper develops a methodology for prototyping increased levels of automation for spacecraft rendezvous functions. This methodology is used to evaluate the accuracy of the Function-specific Level of Autonomy and Automation Tool specified levels of automation, via prototyping. Spacecraft rendezvous planning tasks are selected and then prototyped in Matlab using Fuzzy Logic techniques and existing Space Shuttle rendezvous trajectory algorithms.

Hart, Jeremy J.; Valasek, John

2007-01-01

165

Peer-to-Peer Refuelling within a Satellite Constellation Part I: Zero-Cost Rendezvous Case  

E-print Network

Peer-to-Peer Refuelling within a Satellite Constellation Part I: Zero-Cost Rendezvous Case Haijun in a constellation. The satellites in the constellation are assumed to be capable of refu- elling each other in the constellation after a given period. It is shown that the problem of equalizing the fuel among the satellites can

Tsiotras, Panagiotis

166

Peer-to-Peer Refuelling within a Satellite Constellation Part II: Nonzero-Cost Rendezvous Case  

E-print Network

Peer-to-Peer Refuelling within a Satellite Constellation Part II: Nonzero-Cost Rendezvous Case in a constellation. It is assumed that there is no fuel delivered to the constellation externally. Instead, the satellites in the constellation are assumed to be capable of refuelling each other. The cost

Tsiotras, Panagiotis

167

Selection of den, rendezvous, and resting sites by wolves in the Bialowieza Forest, Poland  

Microsoft Academic Search

We studied wolf (Canis lupus) selection of 19 den, 10 rendezvous, and 31 resting sites found between 1986 and 2000 in the Biaowiea Forest (Poland). Our objective was to determine whether wolves selected sites far from vil- lages, forest edges, and roads, and whether these sites had dense ground cover for concealment. We also tested whether wolves selected a particular

Jörn Theuerkauf; Sophie Rouys; Wlodzimierz Jedrzejewski

2003-01-01

168

Cooperative Receding Horizon Control for Multi-agent Rendezvous Problems in Uncertain Environments  

E-print Network

Cooperative Receding Horizon Control for Multi-agent Rendezvous Problems in Uncertain Environments. INTRODUCTION Multi-agent cooperative control and coordination has be- come an important and growing field environment. Heterogeneity in terms of capability among agents allows a team to complete tasks otherwise

Cassandras, Christos G.

169

Run and tumble, run and reverse, or run reverse and flick - who wins the chemotaxis race?  

NASA Astrophysics Data System (ADS)

Run and tumble of E.coli bacteria is a well understood example of the stochastic cell motion that is alternated in the presence of signaling chemicals. By regulating the tumbling frequency bacteria are able to navigate toward the food sources. Another bacteria that use twitching to move on a surface, M. xanthus, utilize a different strategy - at the end of the run they completely reverse the direction of motion and continue moving in the opposite direction. The frequency of reversals was shown to be connected to the chemotactic response of the cell. Recently yet another pattern was discovered in marine bacteria V. alginolyticus which alternate sharp reversals with flicks -- making a turn to an angle with a broad distribution and centered around 90 degrees. In this work we are presenting a theoretical framework that describes all above motion patterns. As a highlight of the developed approach we find the exact analytical expressions for the mean squared displacement of moving cells for arbitrary distribution of run times. That allows us to quantitatively compare the performance of bacteria exploring the environment with and without signaling chemicals and, therefore, to find the winner of the chemotactic race.

Zaburdaev, Vasily; Denisov, Sergey; Weitz, David

2012-02-01

170

Early Play Arousal, Sex-Typed Play, and Activity Level as Precursors to Later Rough-and-Tumble Play.  

ERIC Educational Resources Information Center

The extent of father's participation in rough-and-tumble (R&T) play with their children when the children were 18 months old, and children's early preferences for play sex-typed as boys' play, were related to levels of children's R&T play in first grade. (MDM)

McBride-Chang, Catherine; Jacklin, Carol Nagy

1993-01-01

171

Monsters, Magic and Mr Psycho: A Biocultural Approach to Rough and Tumble Play in the Early Years of Primary School  

ERIC Educational Resources Information Center

This paper focuses upon the developmental role of rough and tumble (R&T) play with particular attention to the narratives that children use to underpin such activities. A review of the literature suggests that current early years research and practice pays scant attention to children's outdoor free play activities. A piece of original research is…

Jarvis, Pam

2007-01-01

172

Physical Activity Play and Preschool Children's Peer Acceptance: Distinctions between Rough-and-Tumble and Exercise Play  

ERIC Educational Resources Information Center

Research Findings: Two forms of exercise play (toy mediated and non-mediated) and 2 forms of rough-and-tumble (R&T) play (chase and fighting) were examined in relation to preschoolers' peer competence. A total of 148 preschoolers (78 boys, 89 Euro-Americans) were observed during free play at their university-sponsored child care center.…

Lindsey, Eric W.

2014-01-01

173

Application of fuzzy control to computer simulation of tracking and rendezvous test for docking of an adaptive space structure  

NASA Astrophysics Data System (ADS)

This paper describes an extension of the authors' previous analysis on an application of a fuzzy logic control (FLC) to tracking and rendezvous of an adaptive space structure with a moving target in order to examine effectiveness and feasibility of the FLC. The simulation analysis was made to avoid some practical limitation and difficulty encountered in the previous experimental study in which the floating condition in the space was realized by the use of the wire-suspension system. The usefulness is shown of the FLC's using a generalized version of state evaluation rule based on an explicit function of the state variables. A rapid rendezvous is possible if the tracking is made by using the bending-deformation module. When the distance between the docking structure and the target is sufficiently short, the tracking and rendezvous must be controlled by changing the shear-deformation module, and it needs much more time to complete the rendezvous.

Matsuzaki, Yuji; Hosoda, Hiroto

174

Recent developments in electropolishing and tumbling R&D at Fermilab  

SciTech Connect

Fermi National Accelerator Lab (Fermilab) is continuing to improve its infrastructure for research and development on the processing of superconducting radio frequency cavities. A single cell 3.9 GHz electropolishing tool built at Fermilab and operated at an industrial partner was recently commissioned. The EP tool was used to produce a single cell 3.9 GHz cavity that reached an accelerating gradient of 30 MV/m with a quality factor of 5 x 10{sup 9}. A single cell 1.3 GHz cavity was also electropolished at the same industrial vendor using the vendor's vertical full-immersion technique. On their first and only attempt the vendor produced a single cell 1.3 GHz cavity that reached 30 MV/m with a quality factor of 1 x 10{sup 10}. These results will be detailed along with preliminary tumbling results.

Cooper, C.; Brandt, J.; Cooley, L.; Ge, M.; Harms, E.; Khabiboulline, T.; Ozelis, J.; /Fermilab; Boffo, C.; /Babcock Noell, Wuerzburg

2009-10-01

175

Guidance and Navigation for Rendezvous and Proximity Operations with a Non-Cooperative Spacecraft at Geosynchronous Orbit  

NASA Technical Reports Server (NTRS)

The feasibility and benefits of various spacecraft servicing concepts are currently being assessed, and all require that the servicer spacecraft perform rendezvous, proximity, and capture operations with the target spacecraft to be serviced. Many high-value spacecraft, which would be logical targets for servicing from an economic point of view, are located in geosynchronous orbit, a regime in which autonomous rendezvous and capture operations are not commonplace. Furthermore, existing GEO spacecraft were not designed to be serviced. Most do not have cooperative relative navigation sensors or docking features, and some servicing applications, such as de-orbiting of a non-functional spacecraft, entail rendezvous and capture with a spacecraft that may be non-functional or un-controlled. Several of these challenges have been explored via the design of a notional mission in which a nonfunctional satellite in geosynchronous orbit is captured by a servicer spacecraft and boosted into super-synchronous orbit for safe disposal. A strategy for autonomous rendezvous, proximity operations, and capture is developed, and the Orbit Determination Toolbox (ODTBX) is used to perform a relative navigation simulation to assess the feasibility of performing the rendezvous using a combination of angles-only and range measurements. Additionally, a method for designing efficient orbital rendezvous sequences for multiple target spacecraft is utilized to examine the capabilities of a servicer spacecraft to service multiple targets during the course of a single mission.

Barbee, Brent William; Carpenter, J. Russell; Heatwole, Scott; Markley, F. Landis; Moreau, Michael; Naasz, Bo J.; VanEepoel, John

2010-01-01

176

Relative position and attitude estimation of spacecrafts based on dual quaternion for rendezvous and docking  

NASA Astrophysics Data System (ADS)

The capacity to acquire the relative position and attitude information between the chaser and the target satellites in real time is one of the necessary prerequisites for the successful implementation of autonomous rendezvous and docking. This paper addresses a vision based relative position and attitude estimation algorithm for the final phase of spacecraft rendezvous and docking. By assuming that the images of feature points on the target satellite lie within the convex regions, the estimation of the relative position and attitude is converted into solving a convex optimization problem in which the dual quaternion method is employed to represent the rotational and translational transformation between the chaser body frame and the target body frame. Due to the point-to-region correspondence instead of the point-to-point correspondence is used, the proposed estimation algorithm shows good performance in robustness which is verified through computer simulations.

Qiao, Bing; Tang, Shuren; Ma, Kexin; Liu, Zhenya

2013-10-01

177

Model predictive control application to spacecraft rendezvous in mars sample return scenario  

NASA Astrophysics Data System (ADS)

Model Predictive Control (MPC) is an optimization-based control strategy that is considered extremely attractive in the autonomous space rendezvous scenarios. The Online Recon¦guration Control System and Avionics Architecture (ORCSAT) study addresses its applicability in Mars Sample Return (MSR) mission, including the implementation of the developed solution in a space representative avionic architecture system. With respect to a classical control solution High-integrity Autonomous RendezVous and Docking control system (HARVD), MPC allows a signi¦cant performance improvement both in trajectory and in propellant save. Furthermore, thanks to the online optimization, it allows to identify improvements in other areas (i. e., at mission de¦nition level) that could not be known a priori.

Saponara, M.; Barrena, V.; Bemporad, A.; Hartley, E. N.; Maciejowski, J.; Richards, A.; Tramutola, A.; Trodden, P.

2013-12-01

178

The asteroid rendezvous spacecraft. An adaptation study of TIROS/DMSP technology  

NASA Technical Reports Server (NTRS)

The feasibility of using the TIROS/DMSP Earth orbiting meteorological satellite in application to a near Earth asteroid rendezvous mission. System and subsystems analysis was carried out to develop a configuration of the spacecraft suitable for this mission. Mission analysis studies were also done and maneuver/rendezvous scenarios developed for baseline missions to both Anteros and Eros. The fact that the Asteroid mission is the most complex of the Pioneer class missions currently under consideration notwithstanding, the basic conclusion very strongly supports the suitability of the basic TIROS bus for this mission in all systems and subsystems areas, including science accommodation. Further, the modifications which are required due to the unique mission are very low risk and can be accomplished readily. The key issue is that in virtually every key subsystem, the demands of the Asteroid mission are a subset of the basic meteorological satellite mission. This allows a relatively simple reconfiguration to be accomplished without a major system redesign.

1982-01-01

179

Low-Cost Innovation in Spaceflight: The Near Earth Asteroid Rendezvous (NEAR) Shoemaker Mission  

NASA Technical Reports Server (NTRS)

On a spring day in 1996, at their research center in the Maryland countryside, representatives from the Johns Hopkins University Applied Physics Laboratory (APL) presented Administrator Daniel S. Goldin of the National Aeronautics and Space Administration (NASA) with a check for $3.6 million. 1 Two and a half years earlier, APL officials had agreed to develop a spacecraft capable of conducting an asteroid rendezvous and to do so for slightly more than $122 million. This was a remarkably low sum for a spacecraft due to conduct a planetaryclass mission. By contrast, the Mars Observer spacecraft launched in 1992 for an orbital rendezvous with the red planet had cost $479 million to develop, while the upcoming Cassini mission to Saturn required a spacecraft whose total cost was approaching $1.4 billion. In an Agency accustomed to cost overruns on major missions, the promise to build a planetary-class spacecraft for about $100 million seemed excessively optimistic.

McCurdy, Howard E.

2005-01-01

180

Constant thrust glideslope guidance algorithm for rendezvous in multi-body realm  

Microsoft Academic Search

A guidance algorithm for spacecraft approaching a target vehicle in a quasi-halo orbit in the real earth-moon system is presented. The algorithm is based on the numerical solution of the time-variant linearized relative dynamics of RTBP in inertial coordinates. The whole trajectory is divided into several segments. The multi-impulse glideslope idea, traditionally used in the near-earth rendezvous, is employed to

Yijun Lian; Luhua Liu; Yunhe Meng; Guojian Tang; Kejun Chen

2011-01-01

181

Multi-slide-mode-control for fly-around in automatic rendezvous and docking  

Microsoft Academic Search

Fly-around is an important phase in automatic rendezvous and docking (AR&D). The energy expenditure is important indices of fly-around. Multi-slide-mode-control (MSMC) is developed from sliding mode control and its advantage is energy efficient. Based on MSMC, the fly-around trajectory is designed as great circle and fold-line respectively. The simulations show MSMC has good performance in fly-around of AR&D.

Zhao Xia; Jiang Yuxian; Wu Yunjie

2009-01-01

182

Comet exploration - Scientific objectives and mission strategy for a rendezvous with comet Encke.  

NASA Technical Reports Server (NTRS)

A rendezvous mission which includes an extended stay of 80 days or longer in the vicinity of the comet is considered. Such a mission with exploration maneuvers through the coma and tail and circumnavigation of the nucleus is made feasible by the use of solar-electric propulsion. The physical characteristics of comet Encke are examined, giving attention to the icy conglomerate model of the nucleus, solar wind interaction, and chemical composition. Scientific objections are discussed together with mission profile options.

Meissinger, H. F.; Greenstadt, E. W.; Axford, W. I.; Wetherill, G. W.

1973-01-01

183

A feasibility study of unmanned rendezvous and docking in Mars orbit. Volume 1: Summary  

NASA Technical Reports Server (NTRS)

The technical feasibility of achieving automatic rendezvous and docking in Mars orbit as a part of a surface sample return mission was investigated based on using as much existing Viking '75 Orbiter and Lander hardware as possible. Both 1981 and 1983/84 mission opportunities were considered. The principle result of the study was the definition of a three stage 289 kg Mars Ascent Vehicle (MAV) capable of accepting a 1 kg sample, injecting itself into a 2200 km circular orbit, and rendezvousing with an orbiting spacecraft carrying an earth return vehicle. Conclusions are that with state of the art systems plus limited application of new developments in areas where feasibility has already been demonstrated, e.g., solid rocket motor sterilization, it is possible to land a small ascent vehicle capable of automatically ascending and rendezvousing with a modified Viking '75 orbiter spacecraft. The mission can be flown in 1981 or 1983/84, but a dual launch or a larger launch vehicle than the Viking Titan 3 Centaur, or the use of space storable propellants for Mars orbit injection, would be required in the 1983/84 opportunity.

1974-01-01

184

Rapid design and optimization of low-thrust rendezvous/interception trajectory for asteroid deflection missions  

NASA Astrophysics Data System (ADS)

Asteroid deflection techniques are essential in order to protect the Earth from catastrophic impacts by hazardous asteroids. Rapid design and optimization of low-thrust rendezvous/interception trajectories is considered as one of the key technologies to successfully deflect potentially hazardous asteroids. In this paper, we address a general framework for the rapid design and optimization of low-thrust rendezvous/interception trajectories for future asteroid deflection missions. The design and optimization process includes three closely associated steps. Firstly, shape-based approaches and genetic algorithm (GA) are adopted to perform preliminary design, which provides a reasonable initial guess for subsequent accurate optimization. Secondly, Radau pseudospectral method is utilized to transcribe the low-thrust trajectory optimization problem into a discrete nonlinear programming (NLP) problem. Finally, sequential quadratic programming (SQP) is used to efficiently solve the nonlinear programming problem and obtain the optimal low-thrust rendezvous/interception trajectories. The rapid design and optimization algorithms developed in this paper are validated by three simulation cases with different performance indexes and boundary constraints.

Li, Shuang; Zhu, Yongsheng; Wang, Yukai

2014-02-01

185

Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Laboratory  

NASA Technical Reports Server (NTRS)

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as Automated Rendezvous and Docking, AR&D). The crewed versions may also perform AR&D, possibly with a different level of automation and/or autonomy, and must also provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success of the Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the CEV requirements. The relatively low technology readiness of relative navigation sensors for AR&D has been carried as one of the CEV Projects top risks. The AR&D Sensor Technology Project seeks to reduce this risk by increasing technology maturation of selected relative navigation sensor technologies through testing and simulation, and to allow the CEV Project to assess the relative navigation sensors.

Mitchell, J.; Johnston, A.; Howard, R.; Williamson, M.; Brewster, L.; Strack, D.; Cryan, S.

2007-01-01

186

The Data Transfer Kit: A geometric rendezvous-based tool for multiphysics data transfer  

SciTech Connect

The Data Transfer Kit (DTK) is a software library designed to provide parallel data transfer services for arbitrary physics components based on the concept of geometric rendezvous. The rendezvous algorithm provides a means to geometrically correlate two geometric domains that may be arbitrarily decomposed in a parallel simulation. By repartitioning both domains such that they have the same geometric domain on each parallel process, efficient and load balanced search operations and data transfer can be performed at a desirable algorithmic time complexity with low communication overhead relative to other types of mapping algorithms. With the increased development efforts in multiphysics simulation and other multiple mesh and geometry problems, generating parallel topology maps for transferring fields and other data between geometric domains is a common operation. The algorithms used to generate parallel topology maps based on the concept of geometric rendezvous as implemented in DTK are described with an example using a conjugate heat transfer calculation and thermal coupling with a neutronics code. In addition, we provide the results of initial scaling studies performed on the Jaguar Cray XK6 system at Oak Ridge National Laboratory for a worse-case-scenario problem in terms of algorithmic complexity that shows good scaling on 0(1 x 104) cores for topology map generation and excellent scaling on 0(1 x 105) cores for the data transfer operation with meshes of O(1 x 109) elements. (authors)

Slattery, S. R.; Wilson, P. P. H. [Department of Engineering Physics, University of Wisconsin - Madison, 1500 Engineering Dr., Madison, WI 53706 (United States); Pawlowski, R. P. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185 (United States)

2013-07-01

187

Coupling fast water exchange to slow molecular tumbling in Gd3+ chelates: why faster is not always better  

PubMed Central

The influence of dynamics on solution state structure is a widely overlooked consideration in chemistry. Variations in Gd3+ chelate hydration with changing coordination geometry and dissociative water exchange kinetics substantially impact the effectiveness (or relaxivity) of mono-hydrated Gd3+ chelates as T1-shortening contrast agents for MRI. Theory shows that relaxivity is highly dependent upon the Gd3+-water proton distance (rGdH) and yet this distance is almost never considered as a variable in assessing the relaxivity of a Gd3+ chelate as a potential contrast agent. The consequence of this omission can be seen when considering the relaxivity of isomeric Gd3+ chelates that exhibit different dissociative water exchange kinetics. The results described herein show that the relaxivity of a chelate with ‘optimal’ dissociative water exchange kinetics is actually lower than that of an isomeric chelate with ‘sub-optimal’ dissociative water exchange. When the rate of molecular tumbling of these chelates is slowed, an approach that has long been understood to increase relaxivity, the observed difference in relaxivity is increased with the more rapidly exchanging (‘optimal’) chelate exhibiting lower relaxivity than the ‘sub-optimally’ exchanging isomer. The difference between the chelates arises from a non-field dependent parameter: either the hydration number (q) or rGdH. For solution state Gd3+ chelates, changes in the values of q and rGdH are indistinguishable. These parametric expressions simply describe the hydration state of the chelate – i.e. the number and position of closely associating water molecules. The hydration state (q/rGdH6) of a chelate is intrinsically linked to its dissociative water exchange rate kex and the interrelation of these parameters must be considered when examining the relaxivity of Gd3+ chelates. The data presented herein indicates that the changes in the hydration parameter (q/rGdH6) associated with changing dissociative water exchange kinetics has a profound effect on relaxivity and suggest that achieving the highest relaxivities in monohydrated Gd3+ chelates is more complicated than simply “optimizing” dissociative water exchange kinetics. PMID:23841587

Avedano, Stefano; Botta, Mauro; Haigh, Julian S.; Longo, Dario; Woods, Mark

2013-01-01

188

The Space Operations Simulation Center (SOSC) and Closed-loop Hardware Testing for Orion Rendezvous System Design  

NASA Technical Reports Server (NTRS)

The Space Operations Simulation Center (SOSC) at the Lockheed Martin (LM) Waterton Campus in Littleton, Colorado is a dynamic test environment focused on Autonomous Rendezvous and Docking (AR&D) development testing and risk reduction activities. The SOSC supports multiple program pursuits and accommodates testing Guidance, Navigation, and Control (GN&C) algorithms for relative navigation, hardware testing and characterization, as well as software and test process development. The SOSC consists of a high bay (60 meters long by 15.2 meters wide by 15.2 meters tall) with dual six degree-of-freedom (6DOF) motion simulators and a single fixed base 6DOF robot. The large testing area (maximum sensor-to-target effective range of 60 meters) allows for large-scale, flight-like simulations of proximity maneuvers and docking events. The facility also has two apertures for access to external extended-range outdoor target test operations. In addition, the facility contains four Mission Operations Centers (MOCs) with connectivity to dual high bay control rooms and a data/video interface room. The high bay is rated at Class 300,000 (. 0.5 m maximum particles/m3) cleanliness and includes orbital lighting simulation capabilities.

D'Souza, Christopher; Milenkovich, Zoran; Wilson, Zachary; Huich, David; Bendle, John; Kibler, Angela

2011-01-01

189

Control of a space robot for minimal attitude disturbance to the base satellite for capturing a tumbling satellite  

NASA Astrophysics Data System (ADS)

The use of a space manipulator (robot) for capturing a tumbling object is a risky and challenging task, mainly because when the manipulator onboard a servicing satellite (base satellite) intercepts with an external object for capture, the resulting impulse will be transferred along the mechanical arm down to the servicing satellite causing disturbance to the attitude of the satellite. Such disturbance may destabilize the servicing satellite if the captured object is tumbling and the physical contact between the robot end-effector and the object is not controlled properly. Certainly, the risk may be mitigated with a force or impedance control capability of the manipulator. However, the implementation of force or impedance control usually requires the robot to have a joint torque sensing and control capability which is a very expensive requirement for a space manipulator. To date, there has never been a really flown space manipulator having a joint torque control capability. Further, even a force or impedance control capability becomes available, much development is still needed before safe capture of a tumbling object can be confidently tried in a real mission. This paper presents an optimal control strategy for a space manipulator to have minimal impact to the base satellite during a capturing operation. The idea is to first predict an optimal future time and motion state for capturing and then control the manipulator to reach the determined motion state such that, when the tip of the robot maneuvers to and intercepts with the tumbling object, a minimal attitude disturbance to the servicing satellite will occur. The proposed control strategy can be implemented regardless whether the manipulator has a joint torque control capability or not. Since the control acts before a physical contact happens, it will not affect but actually augment any existing force or impedance control capability of the manipulator. The proposed method is demonstrated using a simulation example.

Flores-Abad, Angel; Ma, Ou

2012-06-01

190

In-cylinder tumble flows and performance of a motorcycle engine with circular and elliptic intake ports  

NASA Astrophysics Data System (ADS)

The temporal and spatial evolution processes of the flows in the cylinder of a four-valve, four-stroke, single cylinder, reciprocating motorcycle engine installed with the elliptic and circular intake ports were experimentally studied by using the particle image velocimetry (PIV). The engine was modified to fit the requirements of PIV measurement. The velocity fields measured by the PIV were analyzed and quantitatively presented as the tumble ratio and turbulence intensity. In the symmetry plane, both the circular and elliptic intake ports could initiate a vortex around the central region during the intake stroke. During the compression stroke, the central vortex created in the cylinder of the engine with the circular intake port disappeared, while that in the engine cylinder with the elliptic intake port further developed into the tumble motion. In the offset plane, weak vortical structures were initiated by the bluff-body effect of the intake valves during the intake stroke. The vortical structures induced by the elliptic intake port were more coherent than those generated by the circular intake port; besides, this feature extends to the compression stroke. The cycle-averaged tumble ratio and the turbulence intensity of the engine with the elliptic intake port were dramatically larger than those of the engine with the circular intake port. The measured engine performance was improved a lot by installing the elliptic intake port. The correlation between the flow features and the enhancement of the engine performance were argued and discussed.

Huang, R. F.; Lin, K. H.; Yeh, C.-N.; Lan, J.

2009-01-01

191

Assessing the Size, Stability, and Utility of Isotropically Tumbling Bicelle Systems for Structural Biology  

PubMed Central

Aqueous phospholipid mixtures that form bilayered micelles (bicelles) have gained wide use by molecular biophysicists during the past 20 years for spectroscopic studies of membrane-bound peptides and structural refinement of soluble protein structures. Nonetheless, the utility of bicelle systems may be compromised by considerations of cost, chemical stability, and preservation of the bicelle aggregate organization under a broad range of temperature, concentration, pH, and ionic strength conditions. In the current work, 31P nuclear magnetic resonance (NMR) and atomic force microscopy (AFM) have been used to monitor the size and morphology of isotropically tumbling small bicelles formed by mixtures of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) or 1,2-di-O-tetradecyl-sn-glycero-3-phosphocholine (DIOMPC) with either 1,2-dihexanoyl-sn-glycero-3-phosphocholine (DHPC) or 1,2-di-O-hexyl-sn-glycero-3-phospho-choline (DIOHPC), testing their tolerance of variations in commonly used experimental conditions. 1H-15N 2D NMR has been used to demonstrate the usefulness of the robust DMPC-DIOHPC system for conformational studies of a fatty acid-binding protein that shuttles small ligands to and from biological membranes. PMID:19914202

Wu, Hongwei; Su, Kai; Guan, Xudong; Sublette, M. Elizabeth; Stark, Ruth E.

2009-01-01

192

VOLUME 81, NUMBER 2 P H Y S I C A L R E V I E W L E T T E R S 13 JULY 1998 From Flutter to Tumble: Inertial Drag and Froude Similarity in Falling Paper  

E-print Network

VOLUME 81, NUMBER 2 P H Y S I C A L R E V I E W L E T T E R S 13 JULY 1998 From Flutter to Tumble fundamental motions are observed: side-to-side oscillation (flutter) and end-over-end rotation (tumble. The transition from flutter to tumble occurs at Frc 0.67 6 0.05. We propose a phenomenological model including

Moses, Elisha

193

Third Report of the Task Force on the Shuttle-Mir Rendezvous and Docking Missions  

NASA Technical Reports Server (NTRS)

In May 1994, the Task Force on the Shuttle-Mir Rendezvous and Docking Missions was established by the NASA Advisory Council. Its purpose is to review Phase 1 (Shuttle-Mir) planning, training, operations, rendezvous and docking, and management and to provide interim reports containing specific recommendations to the Advisory Council. Phase 1 represents the building block to create the experience and technical expertise for an International Space Station. The Phase 1 program brings together the United States and Russia in a major cooperative and contractual program that takes advantage of both countries' capabilities. The content of the Phase 1 program consists of the following elements as defined by the Phase 1 Program Management Plan, dated October 6, 1994: Shuttle-Mir rendezvous and docking missions; astronaut long duration presence on Mir Requirements for Mir support of Phase 1 when astronauts are not on board; outfitting Spektr and Priroda modules with NASA science, research, and risk mitigation equipment Related ground support requirements of NASA and the Russian Space Agency (RSA) to support Phase 1 Integrated NASA and RSA launch schedules and manifests The first meeting of the Task Force was held at the Johnson Space Center (JSC) on May 24 and 25, 1994 with a preliminary report submitted to the NASA Advisory Council on June 6, 1994. The second meeting of the Task Force was held at JSC on July 12 and 13, 1994 and a detailed report containing a series of specific recommendations was submitted on July 29, 1994. This report reflects the results of the third Task Force meeting which was held at JSC on 11 and 12 October, 1994. The briefings presented at that meeting reviewed NASA's response to the Task Force recommendations made to date and provided background data and current status on several critical areas which the Task Force had not addressed in its previous reports.

1994-01-01

194

Predicting performance in manually controlled rendezvous and docking through spatial abilities  

NASA Astrophysics Data System (ADS)

Manually controlled rendezvous and docking (manual RVD) is a challenging space task for astronauts. This study aims to identify spatial abilities that are critical for accomplishing manual RVD. Based on task analysis, spatial abilities were deduced to be critical for accomplishing manual RVD. 15 Male participants performed manual RVD task simulations and spatial ability tests (the object-manipulation spatial ability and spatial orientation ability). Participants' performance in the test of visualization of viewpoints (which measures the spatial orientation ability) was found to be significantly correlated with their manual RVD performance, indicating that the spatial orientation ability in the sense of perspective taking is particularly important for accomplishing manual RVD.

Wang, Chunhui; Tian, Yu; Chen, Shanguang; Tian, Zhiqiang; Jiang, Ting; Du, Feng

2014-01-01

195

Embedded Relative Navigation Sensor Fusion Algorithms for Autonomous Rendezvous and Docking Missions  

NASA Technical Reports Server (NTRS)

bd Systems (a subsidiary of SAIC) has developed a suite of embedded relative navigation sensor fusion algorithms to enable NASA autonomous rendezvous and docking (AR&D) missions. Translational and rotational Extended Kalman Filters (EKFs) were developed for integrating measurements based on the vehicles' orbital mechanics and high-fidelity sensor error models and provide a solution with increased accuracy and robustness relative to any single relative navigation sensor. The filters were tested tinough stand-alone covariance analysis, closed-loop testing with a high-fidelity multi-body orbital simulation, and hardware-in-the-loop (HWIL) testing in the Marshall Space Flight Center (MSFC) Flight Robotics Laboratory (FRL).

DeKock, Brandon K.; Betts, Kevin M.; McDuffie, James H.; Dreas, Christine B.

2008-01-01

196

Study on Performance of Integration Control by Man and Machine in Stage of Final Approaching for Spaceship Rendezvous and Docking  

NASA Astrophysics Data System (ADS)

With the development of manned space technology, space rendezvous and docking (RVD) technology will play a more and more important role. The astronauts’ participation in a final close period of man-machine combination control is an important way of RVD technology. Spacecraft RVD control involves control problem of a total of 12 degrees of freedom (location) and attitude which it relative to the inertial space the orbit. Therefore, in order to reduce the astronauts’ operation load and reduce the security requirements to the ground station and achieve an optimal performance of the whole man-machine system, it is need to study how to design the number of control parameters of astronaut or aircraft automatic control system. In this study, with the laboratory conditions on the ground, a method was put forward to develop an experimental system in which the performance evaluation of spaceship RVD integration control by man and machine could be completed. After the RVD precision requirements were determined, 26 male volunteers aged 20-40 took part in the performance evaluation experiments. The RVD integration control success rates and total thruster ignition time were chosen as evaluation indices. Results show that if less than three RVD parameters control tasks were finished by subject and the rest of parameters control task completed by automation, the RVD success rate would be larger than eighty-eight percent and the fuel consumption would be optimized. In addition, there were two subjects who finished the whole six RVD parameters control tasks by enough train. In conclusion, if the astronauts' role should be integrated into the RVD control, it was suitable for them to finish the heading, pitch and roll control in order to assure the man-machine system high performance. If astronauts were needed to finish all parameter control, two points should be taken into consideration, one was enough fuel and another was enough long operation time.

Zhou, Qianxiang; Liu, Zhongqi

197

Membrane interactions in small fast-tumbling bicelles as studied by (31)P NMR.  

PubMed

Small fast-tumbling bicelles are ideal for studies of membrane interactions at molecular level; they allow analysis of lipid properties using solution-state NMR. In the present study we used (31)P NMR relaxation to obtain detailed information on lipid head-group dynamics. We explored the effect of two topologically different membrane-interacting peptides on bicelles containing either dimyristoylphosphocholine (DMPC), or a mixture of DMPC and dimyristoylphosphoglycerol (DMPG), and dihexanoylphosphocholine (DHPC). KALP21 is a model transmembrane peptide, designed to span a DMPC bilayer and dynorphin B is a membrane surface active neuropeptide. KALP21 causes significant increase in bicelle size, as evidenced by both dynamic light scattering and (31)P T2 relaxation measurements. The effect of dynorphin B on bicelle size is more modest, although significant effects on T2 relaxation are observed at higher temperatures. A comparison of (31)P T1 values for the lipids with and without the peptides showed that dynorphin B has a greater effect on lipid head-group dynamics than KALP21, especially at elevated temperatures. From the field-dependence of T1 relaxation data, a correlation time describing the overall lipid motion was derived. Results indicate that the positively charged dynorphin B decreases the mobility of the lipid molecules - in particular for the negatively charged DMPG - while KALP21 has a more modest influence. Our results demonstrate that while a transmembrane peptide has severe effects on overall bilayer properties, the surface bound peptide has a more dramatic effect in reducing lipid head-group mobility. These observations may be of general importance for understanding peptide-membrane interactions. PMID:25497765

Bodor, Andrea; Kövér, Katalin E; Mäler, Lena

2015-03-01

198

3D kinematic and dynamic analysis of the front crawl tumble turn in elite male swimmers.  

PubMed

The aim of this study was to identify kinematic and dynamic variables related to the best tumble turn times (3mRTT, the turn time from 3-m in to 3-m out, independent variable) in ten elite male swimmers using a three-dimensional (3D) underwater analysis protocol and the Lasso (least absolute shrinkage and selection operator) as statistical method. For each swimmer, the best-time turn was analyzed with five stationary and synchronized underwater cameras. The 3D reconstruction was performed using the Direct Linear Transformation algorithm. An underwater piezoelectric 3D force platform completed the set-up to compute dynamic variables. Data were smoothed by the Savitzky-Golay filtering method. Three variables were considered relevant in the best Lasso model (3mRTT=2.58-0.425 RD+0.204 VPe+0.0046 TD): the head-wall distance where rotation starts (RD), the horizontal speed at the force peak (VPe), and the 3D length of the path covered during the turn (TD). Furthermore, bivariate analysis showed that upper body (CUBei) and lower limb extension indexes at first contact (CLLei) were also linked to the turn time (r=-0.65 and p<0.05 for both variables). Thus the best turn times were associated with a long RD, slower VPe and reduced TD. By an early transverse rotation, male elite swimmers reach the wall with a slightly flexed posture that results in fast extension. These swimmers opt for a movement that is oriented forward and they focus on reducing the distance covered. PMID:22176710

Puel, F; Morlier, J; Avalos, M; Mesnard, M; Cid, M; Hellard, P

2012-02-01

199

Proximity Operations Nano-Satellite Flight Demonstration (PONSFD) Rendezvous Proximity Operations Design and Trade Studies  

NASA Astrophysics Data System (ADS)

The Proximity Operations Nano-Satellite Flight Demonstration (PONSFD) program is to demonstrate rendezvous proximity operations (RPO), formation flying, and docking with a pair of 3U CubeSats. The program is sponsored by NASA Ames via the Office of the Chief Technologist (OCT) in support of its Small Spacecraft Technology Program (SSTP). The goal of the mission is to demonstrate complex RPO and docking operations with a pair of low-cost 3U CubeSat satellites using passive navigation sensors. The program encompasses the entire system evolution including system design, acquisition, satellite construction, launch, mission operations, and final disposal. The satellite is scheduled for launch in Fall 2015 with a 1-year mission lifetime. This paper provides a brief mission overview but will then focus on the current design and driving trade study results for the RPO mission specific processor and relevant ground software. The current design involves multiple on-board processors, each specifically tasked with providing mission critical capabilities. These capabilities range from attitude determination and control to image processing. The RPO system processor is responsible for absolute and relative navigation, maneuver planning, attitude commanding, and abort monitoring for mission safety. A low power processor running a Linux operating system has been selected for implementation. Navigation is one of the RPO processor's key tasks. This entails processing data obtained from the on-board GPS unit as well as the on-board imaging sensors. To do this, Kalman filters will be hosted on the processor to ingest and process measurements for maintenance of position and velocity estimates with associated uncertainties. While each satellite carries a GPS unit, it will be used sparsely to conserve power. As such, absolute navigation will mainly consist of propagating past known states, and relative navigation will be considered to be of greater importance. For relative observations, each spacecraft hosts 3 electro-optical sensors dedicated to imaging the companion satellite. The image processor will analyze the images to obtain estimates for range, bearing, and pose, with associated rates and uncertainties. These observations will be fed to the RPO processor's relative Kalman filter to perform relative navigation updates. This paper includes estimates for expected navigation accuracies for both absolute and relative position and velocity. Another key task for the RPO processor is maneuver planning. This includes automation to plan maneuvers to achieve a desired formation configuration or trajectory (including docking), as well as automation to safely react to potentially dangerous situations. This will allow each spacecraft to autonomously plan fuel-efficient maneuvers to achieve a desired trajectory as well as compute adjustment maneuvers to correct for thrusting errors. This paper discusses results from a trade study that has been conducted to examine maneuver targeting algorithms required on-board the spacecraft. Ground software will also work in conjunction with the on-board software to validate and approve maneuvers as necessary.

Griesbach, J.; Westphal, J. J.; Roscoe, C.; Hawes, D. R.; Carrico, J. P.

2013-09-01

200

Effect of whey protein concentrate and sodium chloride addition plus tumbling procedures on technological parameters, physical properties and visual appearance of sous vide cooked beef.  

PubMed

Beef muscles cooked by the sous vide system were evaluated for the effects of pre-injection tumbling, brine addition and post-injection tumbling on technological parameters, physical properties, visual appearance and tissue microstructure. The muscles were injected at 120% (over original weight) with a brine formulated to give a concentration of 3.5% whey protein concentrate and 0.7% sodium chloride on an injected raw product basis. Pre-injection tumbling did not affect most of the evaluated parameters. Brine addition reduced significantly the cooking and total weight losses. Total weight loss was 7.2% for injected muscles, and significantly higher (28.2%) for non-injected ones. Brine incorporation increased pH and reduced shear force values of cooked muscles. Extended post-injection tumbling (5rpm-10h) improved brine distribution and visual appearance, and also diminished the shear force values of cooked muscles. However, this treatment increased the weight losses of post-injection tumbling and cooking-pasteurization stages. PMID:22060988

Szerman, N; Gonzalez, C B; Sancho, A M; Grigioni, G; Carduza, F; Vaudagna, S R

2007-07-01

201

Orbital Express Autonomous Rendezvous and Capture Sensor System (ARCSS) flight test results  

NASA Astrophysics Data System (ADS)

The Orbital Express flight demonstration was established by the Defense Advanced Research Projects Agency (DARPA) to develop and validate key technologies required for cost-effective servicing of next-generation satellites. A contractor team led by Boeing Advanced Network and Space Systems built two mated spacecraft launched atop an Atlas V rocket from Cape Canaveral, Florida, on March 8, 2007. The low earth orbit test flight demonstrated on orbit transfer of hydrazine propellant, transfer of a spare battery between spacecraft and the ability to replace a spacecraft computer on orbit. It also demonstrated autonomous rendezvous and capture (AR&C) using advanced sensor, guidance, and relative navigation hardware and software. This paper summarizes the results of the on-orbit performance testing of the ARCSS (Autonomous Rendezvous and Capture Sensor System). ARCSS uses onboard visible, infrared and laser rangefinder sensors to provide real time data and imagery to the onboard sensor computer. The Boeing-developed Vis-STAR software executing on the sensor computer uses the ARCSS data to provide precision real-time client bearing, range and attitude as needed, from long range to soft capture. The paper summarizes the ARCSS and Vis-STAR on orbit performance.

Leinz, Manny R.; Chen, Chih-Tsai; Beaven, Michael W.; Weismuller, Thomas P.; Caballero, David L.; Gaumer, William B.; Sabasteanski, Peter W.; Scott, Peter A.; Lundgren, Mark A.

2008-04-01

202

COMPASS Final Report: Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER)  

NASA Technical Reports Server (NTRS)

In this study, the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team completed a design for a multi-asteroid (Nereus and 1996 FG3) sample return capable spacecraft for the NASA In-Space Propulsion Office. The objective of the study was to support technology development and assess the relative benefits of different electric propulsion systems on asteroid sample return design. The design uses a single, heritage Orion solar array (SA) (approx.6.5 kW at 1 AU) to power a single NASA Evolutionary Xenon Thruster ((NEXT) a spare NEXT is carried) to propel a lander to two near Earth asteroids. After landing and gathering science samples, the Solar Electric Propulsion (SEP) vehicle spirals back to Earth where it drops off the first sample s return capsule and performs an Earth flyby to assist the craft in rendezvousing with a second asteroid, which is then sampled. The second sample is returned in a similar fashion. The vehicle, dubbed Near Earth Asteroids Rendezvous and Sample Earth Returns (NEARER), easily fits in an Atlas 401 launcher and its cost estimates put the mission in the New Frontier s (NF's) class mission.

Oleson, Steven R.; McGuire, Melissa L.

2009-01-01

203

A Comparison of Trajectory Optimization Methods for the Impulsive Minimum Fuel Rendezvous Problem  

NASA Technical Reports Server (NTRS)

In this paper we present, a comparison of trajectory optimization approaches for the minimum fuel rendezvous problem. Both indirect and direct methods are compared for a variety of test cases. The indirect approach is based on primer vector theory. The direct approaches are implemented numerically and include Sequential Quadratic Programming (SQP). Quasi- Newton and Nelder-Meade Simplex. Several cost function parameterizations are considered for the direct approach. We choose one direct approach that appears to be the most flexible. Both the direct and indirect methods are applied to a variety of test cases which are chosen to demonstrate the performance of each method in different flight regimes. The first test case is a simple circular-to-circular coplanar rendezvous. The second test case is an elliptic-to-elliptic line of apsides rotation. The final test case is an orbit phasing maneuver sequence in a highly elliptic orbit. For each test case we present a comparison of the performance of all methods we consider in this paper.

Hughes, Steven P.; Mailhe, Laurie M.; Guzman, Jose J.

2003-01-01

204

Progress in navigation filter estimate fusion and its application to spacecraft rendezvous  

NASA Technical Reports Server (NTRS)

A new derivation of an algorithm which fuses the outputs of two Kalman filters is presented within the context of previous research in this field. Unlike other works, this derivation clearly shows the combination of estimates to be optimal, minimizing the trace of the fused covariance matrix. The algorithm assumes that the filters use identical models, and are stable and operating optimally with respect to their own local measurements. Evidence is presented which indicates that the error ellipsoid derived from the covariance of the optimally fused estimate is contained within the intersections of the error ellipsoids of the two filters being fused. Modifications which reduce the algorithm's data transmission requirements are also presented, including a scalar gain approximation, a cross-covariance update formula which employs only the two contributing filters' autocovariances, and a form of the algorithm which can be used to reinitialize the two Kalman filters. A sufficient condition for using the optimally fused estimates to periodically reinitialize the Kalman filters in this fashion is presented and proved as a theorem. When these results are applied to an optimal spacecraft rendezvous problem, simulated performance results indicate that the use of optimally fused data leads to significantly improved robustness to initial target vehicle state errors. The following applications of estimate fusion methods to spacecraft rendezvous are also described: state vector differencing, and redundancy management.

Carpenter, J. Russell

1994-01-01

205

Space Shuttle Guidance, Navigation, and Rendezvous Knowledge Capture Reports. Revision 1  

NASA Technical Reports Server (NTRS)

This document is a catalog and readers guide to lessons learned, experience, and technical history reports, as well as compilation volumes prepared by United Space Alliance personnel for the NASA/Johnson Space Center (JSC) Flight Dynamics Division.1 It is intended to make it easier for future generations of engineers to locate knowledge capture documentation from the Shuttle Program. The first chapter covers observations on documentation quality and research challenges encountered during the Space Shuttle and Orion programs. The second chapter covers the knowledge capture approach used to create many of the reports covered in this document. These chapters are intended to provide future flight programs with insight that could be used to formulate knowledge capture and management strategies. The following chapters contain descriptions of each knowledge capture report. The majority of the reports concern the Space Shuttle. Three are included that were written in support of the Orion Program. Most of the reports were written from the years 2001 to 2011. Lessons learned reports concern primarily the shuttle Global Positioning System (GPS) upgrade and the knowledge capture process. Experience reports on navigation and rendezvous provide examples of how challenges were overcome and how best practices were identified and applied. Some reports are of a more technical history nature covering navigation and rendezvous. They provide an overview of mission activities and the evolution of operations concepts and trajectory design. The lessons learned, experience, and history reports would be considered secondary sources by historians and archivists.

Goodman, John L.

2011-01-01

206

Utilization of flash ladar for cooperative and uncooperative rendezvous and capture  

NASA Astrophysics Data System (ADS)

An ideal Rendezvous and Capture (R&C) sensor on a seeker Space Vehicle (SV) would provide accurate relative 6 degree of freedom data for the Guidance Navigation and Control System (GNCS) from far and near, operate autonomously, and provide multifunctional capability. Flash LADAR has the potential to fulfill these requirements. Sandia has developed Scannerless Range Imaging (SRI) LADAR sensors for a multitude of applications. One of the sensors, LDRI, flew onboard the STS97 mission to install the P6 truss and solar panels on the International Space Station. When compared to scanning LADAR, Scannerless LADAR is smaller, lighter, not mechanically complex, and has a much faster image acquisition time. Recently Sandia has demonstrated Flash Scannerless Range Imaging. Flash LADAR enables the capture of a full scene 3-D range image in one acquisition, thus, enabling freeze motion. The technology"s proven ability to accurately image an object as well as capture the image on the move has the potential to provide very accurate static and dynamic position data for the target vehicle relative to the seeker SV. Since no specific requirements are imposed on the target vehicle, the sensor will work equally well on cooperative and uncooperative target vehicles. This sensor technology can also provide docking feature inspection data and perform a detailed inspection of the target vehicle. This paper will describe the applicability of a Flash LADAR sensor for on-orbit cooperative and uncooperative rendezvous and capture.

Habbit, Robert D., Jr.; Nellums, Robert O.; Niese, Aaron D.; Rodriguez, Jose L.

2003-08-01

207

Design and development of guidance navigation and control algorithms for spacecraft rendezvous and docking experimentation  

NASA Astrophysics Data System (ADS)

This paper presents the design of the GNC system of a ground test-bed for spacecraft rendezvous and docking experiments. The test-bed is developed within the STEPS project (Systems and Technologies for Space Exploration). The facility consists of a flat floor and two scaled vehicles, one active chaser and one “semi-active” target. Rendezvous and docking maneuvers are performed floating on the plane with pierced plates as lifting systems. The system is designed to work both with inertial and non-inertial reference frame, receiving signals from navigation sensors as: accelerometers, gyroscopes, laser meter, radio finder and video camera, and combining them with a digital filter. A Proportional-Integrative-Derivative control law and Pulse Width Modulators are used to command the cold gas thrusters of the chaser, and to follow an assigned trajectory with its specified velocity profile. The design and development of the guidance, navigation and control system and its architecture-including the software algorithms-are detailed in the paper, presenting a performance analysis based on a simulated environment. A complete description of the integrated subsystems is also presented.

Guglieri, Giorgio; Maroglio, Franco; Pellegrino, Pasquale; Torre, Liliana

2014-01-01

208

Poisson equations of rotational motion for a rigid triaxial body with application to a tumbling artificial satellite  

NASA Technical Reports Server (NTRS)

A mathematical model is developed for studying the effects of gravity gradient torque on the attitude stability of a tumbling triaxial rigid satellite. Poisson equations are used to investigate the rotation of the satellite (which is in elliptical orbit about an attracting point mass) about its center of mass. An averaging method is employed to obtain an intermediate set of differential equations for the nonresonant, secular behavior of the osculating elements which describe the rotational motions of the satellite, and the averaged equations are then integrated to obtain long-term secular solutions for the osculating elements.

Liu, J. J. F.; Fitzpatrick, P. M.

1975-01-01

209

Correlating field and laboratory rates of particle abrasion, Rio Medio, Sangre de Cristo Mountains, New Mexico  

Microsoft Academic Search

River bed sediments commonly fine downstream due to a combination of particle abrasion, selective transport of finer grains, and fining of the local sediment supply from hillslopes and tributaries. Particle abrasion rates can be directly measured in the laboratory using tumbling barrels and annular flumes, however, scaling experimental particle abrasion rates to the field has proven difficult due to the

P. J. Polito; L. S. Sklar

2006-01-01

210

Q-Learning and p-persistent CSMA based rendezvous protocol for cognitive radio networks operating with shared spectrum activity  

NASA Astrophysics Data System (ADS)

With an increasing demand for spectrum, dynamic spectrum access (DSA) has been proposed as viable means for providing the flexibility and greater access to spectrum necessary to meet this demand. Within the DSA concept, unlicensed secondary users temporarily "borrow" or access licensed spectrum, while respecting the licensed primary user's rights to that spectrum. As key enablers for DSA, cognitive radios (CRs) are based on software-defined radios which allow them to sense, learn, and adapt to the spectrum environment. These radios can operate independently and rapidly switch channels. Thus, the initial setup and maintenance of cognitive radio networks are dependent upon the ability of CR nodes to find each other, in a process known as rendezvous, and create a link on a common channel for the exchange of data and control information. In this paper, we propose a novel rendezvous protocol, known as QLP, which is based on Q-learning and the p-persistent CSMA protocol. With the QLP protocol, CR nodes learn which channels are best for rendezvous and thus adapt their behavior to visit those channels more frequently. We demonstrate through simulation that the QLP protocol provides a rendevous capability for DSA environments with different dynamics of PU activity, while attempting to achieve the following performance goals: (1) minimize the average time-to-rendezvous, (2) maximize system throughput, (3) minimize primary user interference, and (4) minimize collisions among CR nodes.

Watson, Clifton L.; Biswas, Subir

2014-06-01

211

Effect of field size, head motion, and rotational velocity on roll vection and illusory self-tilt in a tumbling room  

NASA Technical Reports Server (NTRS)

The effect of field size, velocity, and visual fixation upon the perception of self-body rotation and tilt was examined in a rotating furnished room. Subjects sat in a stationary chair in the furnished room which could be rotated about the body roll axis. For full-field conditions, complete 360 degrees body rotation (tumbling) was the most common sensation (felt by 80% of subjects). Constant tilt or partial tumbling (less than 360 degrees rotation) occurred more frequently with a small field of view (20 deg). The number of subjects who experienced complete tumbling increased with increases in field of view and room velocity (for velocities between 15 and 30 degrees s-1). The speed of perceived self-rotation relative to room rotation also increased with increasing field of view.

Allison, R. S.; Howard, I. P.; Zacher, J. E.; Oman, C. M. (Principal Investigator)

1999-01-01

212

A Summary of the Rendezvous, Proximity Operations, Docking, and Undocking (RPODU) Lessons Learned from the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) Demonstration System Mission  

NASA Technical Reports Server (NTRS)

The Guidance, Navigation, and Control (GN&C) Technical Discipline Team (TDT) sponsored Dr. J. Russell Carpenter, a Navigation and Rendezvous Subject Matter Expert (SME) from NASA's Goddard Space Flight Center (GSFC), to provide support to the Defense Advanced Research Project Agency (DARPA) Orbital Express (OE) rendezvous and docking flight test that was conducted in 2007. When that DARPA OE mission was completed, Mr. Neil Dennehy, NASA Technical Fellow for GN&C, requested Dr. Carpenter document his findings (lessons learned) and recommendations for future rendezvous missions resulting from his OE support experience. This report captures lessons specifically from anomalies that occurred during one of OE's unmated operations.

Dennehy, Cornelius J.; Carpenter, James R.

2011-01-01

213

Mars Orbit Rendezvous Strategy for the Mars 2003/2005 Sample Return Mission  

NASA Technical Reports Server (NTRS)

The primary objective of the Mars 2003/2005 Sample Return Project is to return Martian surface materials to Earth from two different sites by the year 2008. The baseline mission plan relies heavily on the use of a Mars orbit rendezvous strategy similar to the lunar orbit rendezvous scheme used for the Apollo missions. The 2003 mission consists of a single spacecraft comprised of a Lander, Rover, and Mars ascent vehicle (MAV). The 2003 mission will be launched on a Delta-III-class launch vehicle in May/June 2003 and arrive at Mars in December 2003/January 2004. The Lander deploys the Rover to collect surface samples from several sites and return them to the Lander where they are transferred to a sample canister onboard the MAV. The MAV is launched into a low Mars orbit (targeted for 600 km circular, 45 deg inclination) and releases the sample canister to await retrieval by an Orbiter launched in 2005. (The sample canister is a passive vehicle with no maneuvering capability.) The duration of Mars surface operations is at most about 90 days. The 2005 mission consists of two separate spacecraft: a Lander/Rover/MAV spacecraft identical to that used for the 2003 mission and an Orbiter carrying an Earth Entry Vehicle (EEV). Both spacecraft will be launched on a single Ariane-5 in August 2005 and arrive at Mars in July/August 2006. A second sample canister is delivered to Mars orbit using the same scenario as was used for the 2003 mission. The Orbiter uses aerocapture for insertion into Mars orbit (targeted for 250 x 1400 km, 45 deg inclination). During its approximately one-year stay at Mars, the Orbiter will search for and attempt to rendezvous first with the 2003 sample canister and then with the 2005 sample canister. After retrieval, each sample canister is transferred to the EEV. The Orbiter departs Mars in July 2007 and returns to Earth in October 2008 on a trajectory targeted for landing at the Utah Test and Training Range (UTTR). After deploying the EEV, the Orbiter performs a deflection maneuver to avoid reentry into Earth's atmosphere.

DAmario, Louis A.; Bollman, Willard E.; Lee, Wayne J.; Roncoli, Ralph B.; Smith, John C.

1999-01-01

214

Multi-Sensor Testing for Automated Rendezvous and Docking Sensor Testing at the Flight Robotics Lab  

NASA Technical Reports Server (NTRS)

The Exploration Systems Architecture defines missions that require rendezvous, proximity operations, and docking (RPOD) of two spacecraft both in Low Earth Orbit (LEO) and in Low Lunar Orbit (LLO). Uncrewed spacecraft must perform automated and/or autonomous rendezvous, proximity operations and docking operations (commonly known as AR&D). The crewed missions may also perform rendezvous and docking operations and may require different levels of automation and/or autonomy, and must provide the crew with relative navigation information for manual piloting. The capabilities of the RPOD sensors are critical to the success ofthe Exploration Program. NASA has the responsibility to determine whether the Crew Exploration Vehicle (CEV) contractor-proposed relative navigation sensor suite will meet the requirements. The relatively low technology readiness level of AR&D relative navigation sensors has been carried as one of the CEV Project's top risks. The AR&D Sensor Technology Project seeks to reduce the risk by the testing and analysis of selected relative navigation sensor technologies through hardware-in-the-Ioop testing and simulation. These activities will provide the CEV Project information to assess the relative navigation sensors maturity as well as demonstrate test methods and capabilities. The first year of this project focused on a series of "pathfinder" testing tasks to develop the test plans, test facility requirements, trajectories, math model architecture, simulation platform, and processes that will be used to evaluate the Contractor-proposed sensors. Four candidate sensors were used in the first phase of the testing. The second phase of testing used four sensors simultaneously: two Marshall Space Flight Center (MSFC) Advanced Video Guidance Sensors (AVGS), a laser-based video sensor that uses retroreflectors attached to the target vehicle, and two commercial laser range finders. The multi-sensor testing was conducted at MSFC's Flight Robotics Laboratory (FRL) using the FRL's 6-DOF gantry system, called the Dynamic Overhead Target System (DOTS). The target vehicle for "docking" in the laboratory was a mockup that was representative of the proposed CEV docking system, with added retroreflectors for the AVGS.' The multi-sensor test configuration used 35 open-loop test trajectories covering three major objectives: (l) sensor characterization trajectories designed to test a wide range of performance parameters; (2) CEV-specific trajectories designed to test performance during CEV-like approach and departure profiles; and (3) sensor characterization tests designed for evaluating sensor performance under more extreme conditions as might be induced during a spacecraft failure or during contingency situations. This paper describes the test development, test facility, test preparations, test execution, and test results of the multisensor series oftrajectories

Brewster, Linda L.; Howard, Richard T.; Johnston, A. S.; Carrington, Connie; Mitchell, Jennifer D.; Cryan, Scott P.

2008-01-01

215

Wookie Rendezvous  

E-print Network

-tempered and short on formality at any time, Han simply strode in, disconnected the power feed to the Sim Trainerand startedasking questions. "Slow down, HanP'Luke pleaded. "What's wrong?" "What's wrong?" Solo scowled. "Oh nothing, nothing at all! No one knows... doing here? Get out!" "What do I want? I came to see if you'd been knifed in your sleep. I ain't going anywhere 'til I find out what's wrong." Han set his jaw defiantly, and stood there with his hands on hips. Leia burst into tears. "Princess...

Multiple Contributors

1999-01-01

216

Mission Design for a Multiple-Rendezvous Mission to Jupiter's Trojans  

NASA Astrophysics Data System (ADS)

In this paper, we will provide a feasible mission design for a multiple-rendezvous mission to Jupiter's Trojans. It is based on solar electric propulsion, as being currently used on the DAWN spacecraft, and other flight-proven technology. First, we have selected a set of mission objectives, the prime objective being the detection of water -especially subsurface water -to provide evidence for the Trojans' formation at large solar distances. Based on DAWN and other comparable missions, we have determined suitable payload instruments to achieve these objectives. Afterwards, we have designed a spacecraft that is able to carry the selected payload to the Trojan region and rendezvous successively with three target bodies within a maximum mission duration of 15 years. Accurate low-thrust trajectories have been obtained with a global low-thrust trajectory optimization program (InTrance). During the transfer from Earth to the first target, the spacecraft is propelled by two RIT-22 ion engines from EADS Astrium, whereas a single RIT-15 is used for transfers within the Trojan region to reduce the required power. For power generation, the spacecraft uses a multi-junction solar array that is supported by concentrators. To achieve moderate mission costs, we have restricted the launch mass to a maximum of 1600 kg, the maximum interplanetary injection capability of a Soyuz/Fregat launcher. Our final layout has a mass of 1400 kg, yielding a margin of about 14%. Nestor (a member of the L4-population) was determined as the first mission target. It can be reached within 4.6 years from launch. The fuel mass ratio for this transfer is about 35%. The stay time at Nestor is 1.2 years. Eurymedon was selected as the second target (transfer time 3.5 years, stay time 3.0 years) and Irus as the third target (transfer time 2.2 years). The transfers within the Trojan L4-population can be accomplished with fuel mass ratios of about 3% for each trajectory leg. Including the stay times in orbit around the targets, the mission can be accomplished within a total duration of about 14.5 years. According to our mission analysis, it is also feasible to fly to the L5-population with similar flight times. It has to be noted that -for a first analysis -we have taken only the named targets into account. Allowing also rendezvous with unnamed objects will very likely decrease the mission duration. Based on a scaling of DAWN's mission costs (due to comparable scientific instruments and mission objectives), and taking into account the longer mission duration and the potential re-use of already developed technology, we have estimated that these three rendezvous can be accomplished with a budget of about 250 Million Euros, i.e. about 25% of ROSETTA's budget.

Maiwald, Volker; Dachwald, Bernd

217

Report of the Task Force on the Shuttle-Mir Rendezvous and Docking Missions  

NASA Technical Reports Server (NTRS)

In October 1992, Russia and the U.S. agreed to conduct a fundamentally new program of human cooperation in space. This original 'Shuttle-Mir' project encompassed combined astronaut-cosmonaut activities on the Shuttle, Soyuz, and Mir spacecraft. At that time, the project was limited to: the STS-60 Shuttle mission, which was completed in February 1994 and carried the first Russian cosmonaut; the planned March 1995 Soyuz 18 launch which will carry a U.S. astronaut to the Mir space station for a three month mission; and the STS-71 Shuttle mission which is scheduled to rendezvous and dock with the Mir space station in June 1995. The Task Force's specific recommendations are given.

1994-01-01

218

Autonomous rendezvous and docking: A commercial approach to on-orbit technology validation  

NASA Technical Reports Server (NTRS)

SpARC, in conjunction with its corporate affiliates, is planning an on-orbit validation of autonomous rendezvous and docking (ARD) technology. The emphasis in this program is to utilize existing technology and commercially available components wherever possible. The primary subsystems to be validated by this demonstration include GPS receivers for navigation, a video-based sensor for proximity operations, a fluid connector mechanism to demonstrate fluid resupply capability, and a compliant, single-point docking mechanism. The focus for this initial experiment will be ELV based and will make use of two residual Commercial Experiment Transporter (COMET) service modules. The first COMET spacecraft will be launched in late 1992 and will serve as the target vehicle. After the second COMET spacecraft has been launched in late 1994, the ARD demonstration will take place. The service module from the second COMET will serve as the chase vehicle.

Tchoryk, Peter, Jr.; Whitten, Raymond P.

1991-01-01

219

Orbit determination for the Mariner Mark II Comet Rendezvous/Asteroid Flyby mission - The orbiting phase  

NASA Technical Reports Server (NTRS)

The Comet Rendezvous/Asteroid Flyby (CRAF) mission is the first of the Mariner Mark II mission set, designed to explore the outer solar system. Major objectives of orbit determination will be determine the positions and masses of the comet and asteroid and the relative position of the spacecraft, which is important to accurate pointing of the scan platform on which the narrow angle camera and scientific instruments are positioned. Position prediction is also important, since continuous commuication with the spacecraft will not be possible. The small gravitational attractions and poorly known ephemerides of the comet and asteroid, and the small, slow spacecraft orbit about the comet, pose significant new problems for orbit determination. Results of simulations studying the effectiveness of key data types, the accuracies of estimates, and prediction capabilities, are presented.

Weeks, C. J.

1986-01-01

220

Orbit determination for the Mariner Mark II Comet Rendezvous/Asteroid Flyby mission - The orbiting phase  

NASA Astrophysics Data System (ADS)

The Comet Rendezvous/Asteroid Flyby (CRAF) mission is the first of the Mariner Mark II mission set, designed to explore the outer solar system. Major objectives of orbit determination will be determine the positions and masses of the comet and asteroid and the relative position of the spacecraft, which is important to accurate pointing of the scan platform on which the narrow angle camera and scientific instruments are positioned. Position prediction is also important, since continuous commuication with the spacecraft will not be possible. The small gravitational attractions and poorly known ephemerides of the comet and asteroid, and the small, slow spacecraft orbit about the comet, pose significant new problems for orbit determination. Results of simulations studying the effectiveness of key data types, the accuracies of estimates, and prediction capabilities, are presented.

Weeks, C. J.

1986-08-01

221

Laparoscopic-endoscopic rendez-vous resection of iuxta-cardial gastric GIST  

PubMed Central

Summary: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract and they often require a surgical removal. Gastrointestinal stromal tumors can originate from any part of the gastrointestinal tract but gastric location is the most common. In the past the risk of rupture of pseudocapsula and peritoneal dissemination have discouraged surgeons from making a minimally invasive surgical treatment. Recently laparoscopic wedge resection has been proposed. Performance of this mini-invasive technique is however difficult in some gastric location of gastrointestinal stromal tumors, such as iuxta-cardial region. The Authors report and discuss a new technique they used to remove a gastrointestinal stromal tumor located just below the cardia, using a rendez-vous endoscopic and laparoscopic technique. PMID:23837950

VECCHIO, R.; MARCHESE, S.; AMORE, F.F.; LA CORTE, F.; FERLA, F.; SPATARO, L.; INTAGLIATA, E.

2013-01-01

222

Analysis of a Linear System for Variable-Thrust Control in the Terminal Phase of Rendezvous  

NASA Technical Reports Server (NTRS)

A linear system for applying thrust to a ferry vehicle in the 3 terminal phase of rendezvous with a satellite is analyzed. This system requires that the ferry thrust vector per unit mass be variable and equal to a suitable linear combination of the measured position and velocity vectors of the ferry relative to the satellite. The variations of the ferry position, speed, acceleration, and mass ratio are examined for several combinations of the initial conditions and two basic control parameters analogous to the undamped natural frequency and the fraction of critical damping. Upon making a desirable selection of one control parameter and requiring minimum fuel expenditure for given terminal-phase initial conditions, a simplified analysis in one dimension practically fixes the choice of the remaining control parameter. The system can be implemented by an automatic controller or by a pilot.

Hord, Richard A.; Durling, Barbara J.

1961-01-01

223

Development of an autonomous video rendezvous and docking system, phase 2  

NASA Technical Reports Server (NTRS)

The critical elements of an autonomous video rendezvous and docking system were built and used successfully in a physical laboratory simulation. The laboratory system demonstrated that a small, inexpensive electronic package and a flight computer of modest size can analyze television images to derive guidance information for spacecraft. In the ultimate application, the system would use a docking aid consisting of three flashing lights mounted on a passive target spacecraft. Television imagery of the docking aid would be processed aboard an active chase vehicle to derive relative positions and attitudes of the two spacecraft. The demonstration system used scale models of the target spacecraft with working docking aids. A television camera mounted on a 6 degree of freedom (DOF) simulator provided imagery of the target to simulate observations from the chase vehicle. A hardware video processor extracted statistics from the imagery, from which a computer quickly computed position and attitude. Computer software known as a Kalman filter derived velocity information from position measurements.

Tietz, J. C.; Richardson, T. E.

1983-01-01

224

A combined open-loop and autonomous search and rendezvous navigation system for the CNES/NASA Mars Premier Orbiter mission  

NASA Technical Reports Server (NTRS)

This paper will describe the search methods to be used using the radio and optical observations, and will provide a description of the methods and performance of the autonomous onboard rendezvous navigation system.

Riedel, J. E.; Guinn, J.; Delpech, M.; Dubois, J. B.; Geller, D.; Katchmar, P.

2003-01-01

225

A novel approach to heat transfer enhancement using trapezoid shaped spiral strips to promote tumble and swirl in a slot shaped channel used in heat exchangers  

E-print Network

Heat transfer results for a given slot shaped channel with a 3:1 aspect ratio are presented using various configurations of a trapezoid shaped spiral wound strips to enhance swirl and tumble motion in the channel. The Reynolds numbers investigated...

Segura, D.; Acharya, S.

2012-01-01

226

Androgen and the Development of Human Sex-Typical Behavior: Rough-and-Tumble Play and Sex of Preferred Playmates in Children with Congenital Adrenal Hyperplasia (CAH).  

ERIC Educational Resources Information Center

Examined the rough-and-tumble play and gender of preferred playmates in three- to eight-year olds with congenital adrenal hyperplasia (CAH)--hypothesized to masculinize behaviors that show sex differences--and in unaffected three- to eight-year-old relatives. Found that CAH girls did not exhibit increased levels of masculine behavior when compared…

Hines, Melissa; Kaufman, Francine R.

1994-01-01

227

Perspective and Practices to Address Rough-and-Tumble Play in the School Setting: A Survey of School-Wide Positive Behavior Support Teams in Utah  

ERIC Educational Resources Information Center

Prior research of rough-and-tumble play (RTP) has shown mixed results--different definitions, varying functions, and positive and negative outcomes. Few researchers have studied interventions to address RTP in school settings. With unclear evidence of RTP outcomes and the extent school interventions are addressing RTP in school settings, this…

Basinger, Jason Christopher

2012-01-01

228

Evaluation of GPS position and attitude determination for automated rendezvous and docking missions. M.S. Thesis  

NASA Technical Reports Server (NTRS)

The use of the Global Positioning System for position and attitude determination is evaluated for an automated rendezvous and docking mission. The typical mission scenario involves the chaser docking with the target for resupply or repair purposes, and is divided into three sections. During the homing phase, the chaser utilizes coarse acquisition pseudorange data to approach the target; guidance laws for this stage are investigated. In the second phase, differential carrier phase positioning is utilized. The chaser must maintain a quasiconstant distance from the target, in order to resolve the initial integer ambiguities. Once the ambiguities are determined, the terminal phase is entered, and the rendezvous is completed with continuous carrier phase tracking. Attitude knowledge is maintained in all phases through the use of the carrier phase observable. A Kalman filter is utilized to estimate all states from the noisy measurement data. The effects of selective availability and cycle slips are also investigated.

Diprinzio, Marc D.; Tolson, Robert H.

1994-01-01

229

Opportunity options for rendezvous, flyby and sample return mission to different spectral-type asteroids for the 2015-2025  

NASA Astrophysics Data System (ADS)

The feasible rendezvous, flyby and sample return mission scenario to different spectral-type asteroids for the 2015-2025 are investigated. The emphasis is put on the potential target selection and the design of preliminary interplanetary transfer trajectory in this paper. First, according to different scientific motivations, some potential targets with different spectral-type and physical property are selected. Then, some optimal rendezvous and sample return opportunities for different spectral-type asteroids are presented by using pork-chop plots method and Sequential Quadratic-Programming (SQP) algorithm. In order to reduce the launch energy and total velocity increments for sample return mission, the Earth swingby strategy is used. In addition, the feasible trajectory profiles of flyby and rendezvous with two different spectral-type asteroids in one mission are discussed. A hybrid optimization method combing the Differential Evolution (DE) algorithm and SQP algorithm is introduced as a trajectory design method for the mission. Finally, some important parameters of transfer trajectory are analyzed, which would have a direct impact on the design of spacecraft subsystem, such as communication, power and thermal control subsystem.

Dong, Qiao; Pingyuan, Cui; Yamin, Wang

2012-03-01

230

Autonomous rendezvous and docking: A commercial approach to on-orbit technology validation  

NASA Technical Reports Server (NTRS)

The Space Automation and Robotics Center (SpARC), a NASA-sponsored Center for the Commercial Development of Space (CCDS), in conjunction with its corporate affiliates, is planning an on-orbit validation of autonomous rendezvous and docking (ARD) technology. The emphasis in this program is to utilize existing technology and commercially available components whenever possible. The primary subsystems that will be validated by this demonstration include GPS receivers for navigation, a video-based sensor for proximity operations, a fluid connector mechanism to demonstrate fluid resupply capability, and a compliant, single-point docking mechanism. The focus for this initial experiment will be expendable launch vehicle (ELV) based and will make use of two residual Commercial Experiment Transporter (COMET) service modules. The first COMET spacecraft will be launched in late 1992 and will serve as the target vehicle. The ARD demonstration will take place in late 1994, after the second COMET spacecraft has been launched. The service module from the second COMET will serve as the chase vehicle.

Tchoryk, Peter, Jr.; Dobbs, Michael E.; Conrad, David J.; Apley, Dale J.; Whitten, Raymond P.

1991-01-01

231

The applications of laser tracking and ranging technology in space rendezvous and docking  

NASA Astrophysics Data System (ADS)

With the development of space technology, more and more Rendezvous and Docking (RVD) mission require more precise measurement of relative position and attitude between tracking spacecraft and target spacecraft. In the procedure of docking between near spacecraft , the optical retroreflector on the target Spacecraft were tracked by the laser tracking and ranging device on the tracking spacecraft , the distance data were provided by laser ranging system, and the azimuth data were provided by tracking gimbal, Synthesized the distance data and azimuth data, the relative position information between two spacecraft were provided to the target spacecraft. Furthermore, through tracking more than three point on the target spacecraft ,the complete information of relative position and attitude between two spacecraft were calculated rapidly by the measurement system?which were presented to the control system during the whole RVD operating stage. The laser tracking technology guaranteed continuous measurement and supplied accurate azimuth information, and the laser ranging technology ensured high accuracy of distance information. In addition, the untouched measure mode give no disturbance to the docking operation, moreover, the monochromaticity of laser make the tracking and ranging procedure avoiding to be disturbed by parasitic light of space, thus there will be a effective measurement accompanying the whole docking operating procedure and affording valid data to the control system of docking.

She, Wenji; Gao, Limin; Zhou, Liang; Li, Dawei; Wang, Rong

2013-09-01

232

The Ion Propulsion System on NASA's Space Technology 4/Champollion Comet Rendezvous Mission  

NASA Technical Reports Server (NTRS)

The ST4/Champollion mission is designed to rendezvous with and land on the comet Tempel 1 and return data from the first-ever sampling of a comet surface. Ion propulsion is an enabling technology for this mission. The ion propulsion system on ST4 consists of three ion engines each essentially identical to the single engine that flew on the DS1 spacecraft. The ST4 propulsion system will operate at a maximum input power of 7.5 kW (3.4 times greater than that demonstrated on DS1), will produce a maximum thrust of 276 mN, and will provide a total (Delta)V of 11.4 km/s. To accomplish this the propulsion system will carry 385 kg of xenon. All three engines will be operated simultaneously for the first 168 days of the mission. The nominal mission requires that each engine be capable of processing 118 kg. If one engine fails after 168 days, the remaining two engines can perform the mission, but must be capable of processing 160 kg of xenon, or twice the original thruster design requirement. Detailed analyses of the thruster wear-out failure modes coupled with experience from long-duration engine tests indicate that the thrusters have a high probability of meeting the 160-kg throughput requirement.

Brophy, John R.; Garner, Charles E.; Weiss, Jeffery M.

1999-01-01

233

Fourth Report of the Task Force on the Shuttle-Mir Rendezvous and Docking Missions  

NASA Technical Reports Server (NTRS)

On December 6, 1994, the NASA Administrator, Mr. Daniel Goldin, requested that Lt. Gen. Thomas P. Stafford, in his role as the Chairman of the NASA Advisory Council Task Force on the Shuttle-Mir Rendezvous and Docking Missions, lead a team composed of several Task Force members and technical advisors' to Russia with the goal of reviewing preparations and readiness for the upcoming international Space Station Phase 1 missions. In his directions to Gen. Stafford, Mr. Goldin requested that the review team focus its initial efforts on safety of flight issues for the following Phase 1A missions: the Soyuz TM-21 mission which will carry U.S. astronaut Dr. Norman Thagard and cosmonauts Lt. Col. Vladimir Dezhurov and Mr. Gennady Strekalov aboard a Soyuz spacecraft to the Mir Station; the Mir 18 Main Expedition during which Thagard and his fellow cosmonauts, Dezhurov and Strokalov, will spend approximately three months aboard the Mir Station; the STS-71 Space Shuttle mission which will perform the first Shuttle-Mir docking, carry cosmonauts Col. Anatoly SoloViev and Mr. Nikolai Budarin to the Mir Station, and return Thagard, Dezhurov, and Strekalov to Earth.

1995-01-01

234

Testing heterogeneity in faunal assemblages from archaeological sites. Tumbling and trampling experiments at the early-Middle Pleistocene site of Gesher Benot Ya’aqov (Israel)  

Microsoft Academic Search

The current paper reports an experimental case study to test the heterogeneity of faunal assemblages from the Early-Middle Pleistocene Layers V-5 and V-6 of the Gesher Benot Ya’aqov Acheulian site (Israel). Tumbling and trampling experiments were initiated to gain qualitative insight into processes of bone modification and to assess the timing of the biostratonomic chronology, as it was assumed that

Sabine Gaudzinski-Windheuser; Lutz Kindler; Rivka Rabinovich; Naama Goren-Inbar

2010-01-01

235

Effect of the natural state of an elastic cellular membrane on tank-treading and tumbling motions of a single red blood cell.  

PubMed

A two-dimensional computer simulation model was proposed for tank-treading and tumbling motions of an elastic biconcave red blood cell (RBC) under steady shear flow. The RBC model consisted of an outer cellular membrane and an inner fluid; the membrane's elastic properties were modeled by springs for stretch/compression and bending to consider the membrane's natural state in a practical manner. Membrane deformation was coupled with incompressible viscous flow of the inner and outer fluids of the RBC using a particle method. The proposed simulation model was capable of reproducing tank-treading and tumbling motions of an RBC along with rotational oscillation, which is the transition between the two motions. In simulations using the same initial RBC shape with different natural states of the RBC membrane, only tank-treading motion was exhibited in the case of a uniform natural state of the membrane, and a nonuniform natural state was necessary to generate the rotational oscillation and tumbling motion. Simulation results corresponded to published data from experimental and computational studies. In the range of simulation parameters considered, the relative membrane elastic force versus fluid viscous force was approximately 1 at the transition when the natural state nonuniformity was taken into account in estimating the membrane elastic force. A combination of natural state nonuniformity and elastic spring constant determined that change in the RBC deformation at the transition is that from a large compressive deformation to no deformation, such as rigid body. PMID:20365402

Tsubota, Ken-ichi; Wada, Shigeo

2010-01-01

236

Rendezvous, Landing and Sample Return Mission to Jupiter Trojans by the Solar Power Sail  

NASA Astrophysics Data System (ADS)

JAXA/ISAS has been preparing for the Solar Power Sail mission, Japan’s first outer planet region exploration. Its precursor was successfully realized by IKAROS, the world's first deep space solar sail spacecraft, in 2010 between the Earth and Venus orbits. The Solar Power Sail is defined primarily as a technology demonstration mission; yet it will also present game-changing opportunities for both space astronomy and solar system exploration. The former will benefit the cruising operation, which will enable ”dust free” infrared astronomy beyond the cocoon of the zodiacal light to search for the first generation light of the Universe. Interplanetary-long baseline will allow gamma-ray burst observation to identify their source locations much more precise than ever. As for solar system exploration, the Solar Power Sail, which is not depended upon RTG technology, will offer the world's first possibility of rendezvous, landing and sample return from the outer planet region, i.e., in the Jupiter region and beyond. With this technology, we are aiming to visit Jupiter Trojan asteroids, one of the last uncharted frontiers of the Solar System. Jupiter Trojans may hold fundamental clues of the Solar System formation and revolution discussed by two competing hypotheses between the classic model and the planetary migration model. The former suggests that Trojan asteroids are mainly survivors of building blocks of the Jupiter system, while the latter claims that they must be intruders from outer regions after the planetary migration of gas planets settled. This paper outlines scientific objectives of Jupiter Trojan exploration, its mission design and major aspects of the spacecraft system, nature of candidate target asteroids, in-situ observation and lander instruments including optical camera, imaging spectrometer, high-resolution TOF mass spectrometer, and large-area dust counter, together with a strategy of the sample return option from the surface of a Trojan asteroid.

Yano, Hajime; Matsuura, Shuji; Mori, Osamu; Yonetoku, Daisuke; Nakamura, Ryosuke; Sekine, Yasuhito; Abe, Shinsuke

237

Application of solar electric propulsion to comet and asteroid rendezvous and docking /CARD/ missions with sample return.  

NASA Technical Reports Server (NTRS)

Summary of a feasibility study of CARD mission/system concepts for comet Encke and asteroid Eros missions in the late 1970s. A common planetary vehicle employing a modular SEP (solar electric propulsion) system and a direct rendezvous/docking mode with a staged science/sampling module appears feasible based on 1973 technology. The SEP system utilizes 3.5-kW, 3500-sec Isp mercury ion thrusters and rollout solar arrays sized at 36 (Encke) and 13 (Eros) kW based on the Titan III family launch vehicles. Science payloads, sampling concepts, and supporting spacecraft subsystems are defined. Problem areas are identified, and programmatic considerations are discussed.

Odom, P. R.; Cikanek, H. A.; Allen, L. C.

1972-01-01

238

Enhancing Physicochemical Properties and Indium Leachability of Indium-Bearing Zinc Ferrite Mechanically Activated Using Tumbling Mill  

NASA Astrophysics Data System (ADS)

The synthetic indium-bearing zinc ferrite (IBZF) was activated mechanically using a tumbling mill under different rotation speeds, milling times, media fillings, and ball-to-material ratios. Subsequently, the changes in the physicochemical properties and leaching behavior of IBZF induced by mechanical activation were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), Mössbauer spectrometry, particle size analysis, and leaching tests in sulfuric acid. The results showed that different milling conditions could form different particle size distribution, morphologies, and crystal structures, which influenced indium extraction differently. In addition, the indium extractions from various activated samples were related closely to the changes of physicochemical properties induced by mechanical activation. The strengthening effect of mechanical activation in IBZF decomposition lies mainly in the damage of crystal structure besides the decrease of the particle size because the indium-leaching efficiencies increased significantly with the increase of the damage of the crystal structure when the particle size is kept constant.

Yao, Jinhuan; Li, Xuanhai; Pan, Liuping; Mo, Jiamei

2012-06-01

239

NASA's Automated Rendezvous and Docking/Capture Sensor Development and Its Applicability to the GER  

NASA Technical Reports Server (NTRS)

This paper will address how a common Automated Rendezvous and Docking/Capture (AR&D/C) sensor suite can support Global Exploration Roadmap (GER) missions, and discuss how the model of common capability development to support multiple missions can enable system capability level partnerships and further GER objectives. NASA has initiated efforts to develop AR&D/C sensors, that are directly applicable to GER. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion crew vehicle. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a three-dimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build time instead of at design time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal nonrecurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. NASA's AR&D/C sensor development path could benefit the International Exploration Coordination Group (ISECG) and support the GER mission scenario by providing a common sensor suite upon which GER objectives could be achieved while minimizing development costs. The paper will describe the concepts of operations of these missions and how the common sensors are utilized by each mission. It will also detail the potential partnerships and contribution of the International community in the development of this common AR&D/C sensor suite.

Hinkel, Heather; Cryan, Scott; DSouza, Christopher; Strube, Matthew

2014-01-01

240

TASTER: Trojan ASteroid Tour, Exploration and Rendezvous, a NASA Planetary Science Summer School Mission Design Exercise  

NASA Astrophysics Data System (ADS)

A detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrangian points has been identified as a priority for future missions by the 2011 Planetary Science Decadal Survey. Observing these asteroids and getting clear measurements of their physical characteristics and composition may yield answers to fundamental questions relating to the early Solar System. In particular, Trojan asteroids are believed to harbor primordial material dating from the time of its formation. The source region for Trojans is still unknown; the Nice model predicts that some bodies may have originated in the primordial Kuiper belt and were subsequently scattered inward during the migration of Neptune and Uranus and settled in their current location. In alternative models, less radial scattering of small bodies would imply Trojans formed from material at a similar orbital distance to Jupiter. Determination of Trojan composition and structure will help identify their birth location, provide information about the impact history and subsequent evolution. Earth-based observations of size and surface characteristics are sparse; spectral measurements are unable to resolve composition (and show a puzzling lack of volatile signatures), indicating that close-range observation is needed. We present a mission design for a Trojan Tour and Rendezvous mission that is consistent with NASA's New Frontiers candidate recommended by the Decadal Survey, and which is the final result of the 2011 NASA-JPL Planetary Science Summer School Mission Design Exercise. Our proposed mission includes a tour phase that features a 500 km altitude fly-by of 1999 XS143. The spacecraft will then orbit and make detailed observations of 1919FD Agamemnon, a 167 km diameter asteroid located in the leading Lagrangian point (L4), from orbital altitudes of 1000 - 100 km over a 12 month nominal science data capture period. The mission's planned primary observations aim to (1) detect and identify volatile species and rock-forming elements on or just below the surface, (2) map the surface geology, and (3) determine size, shape, and rotational state. Our payload will provide unprecedented high-resolution, global dataset for the target bodies, yielding crucial information about the early history and evolution of the Solar System.

Diaz-silva, R.; Sayanagi, K. M.; Gil, S.; Diniega, S.; Balcerski, J.; Benneke, B.; Carande, B.; Fraeman, A. A.; Hudson, J. S.; Guzewich, S. D.; Livi, R.; Nahm, A.; Potter, S.; Route, M.; Urban, K. D.; Vasisht, S.; Williams, B.; Budney, C. J.; Lowes, L. L.

2011-12-01

241

String method for calculation of minimum free-energy paths in Cartesian space in freely-tumbling systems.  

PubMed

The string method is a molecular-simulation technique that aims to calculate the minimum free-energy path of a chemical reaction or conformational transition, in the space of a pre-defined set of reaction coordinates that is typically highly dimensional. Any descriptor may be used as a reaction coordinate, but arguably the Cartesian coordinates of the atoms involved are the most unprejudiced and intuitive choice. Cartesian coordinates, however, present a non-trivial problem, in that they are not invariant to rigid-body molecular rotations and translations, which ideally ought to be unrestricted in the simulations. To overcome this difficulty, we reformulate the framework of the string method to integrate an on-the-fly structural-alignment algorithm. This approach, referred to as SOMA (String method with Optimal Molecular Alignment), enables the use of Cartesian reaction coordinates in freely tumbling molecular systems. In addition, this scheme permits the dissection of the free-energy change along the most probable path into individual atomic contributions, thus revealing the dominant mechanism of the simulated process. This detailed analysis also provides a physically-meaningful criterion to coarse-grain the representation of the path. To demonstrate the accuracy of the method we analyze the isomerization of the alanine dipeptide in vacuum and the chair-to-inverted-chair transition of ?-D mannose in explicit water. Notwithstanding the simplicity of these systems, the SOMA approach reveals novel insights into the atomic mechanism of these isomerizations. In both cases, we find that the dynamics and the energetics of these processes are controlled by interactions involving only a handful of atoms in each molecule. Consistent with this result, we show that a coarse-grained SOMA calculation defined in terms of these subsets of atoms yields nearidentical minimum free-energy paths and committor distributions to those obtained via a highly-dimensional string. PMID:24729762

Branduardi, Davide; Faraldo-Gómez, José D

2013-09-10

242

String method for calculation of minimum free-energy paths in Cartesian space in freely-tumbling systems  

PubMed Central

The string method is a molecular-simulation technique that aims to calculate the minimum free-energy path of a chemical reaction or conformational transition, in the space of a pre-defined set of reaction coordinates that is typically highly dimensional. Any descriptor may be used as a reaction coordinate, but arguably the Cartesian coordinates of the atoms involved are the most unprejudiced and intuitive choice. Cartesian coordinates, however, present a non-trivial problem, in that they are not invariant to rigid-body molecular rotations and translations, which ideally ought to be unrestricted in the simulations. To overcome this difficulty, we reformulate the framework of the string method to integrate an on-the-fly structural-alignment algorithm. This approach, referred to as SOMA (String method with Optimal Molecular Alignment), enables the use of Cartesian reaction coordinates in freely tumbling molecular systems. In addition, this scheme permits the dissection of the free-energy change along the most probable path into individual atomic contributions, thus revealing the dominant mechanism of the simulated process. This detailed analysis also provides a physically-meaningful criterion to coarse-grain the representation of the path. To demonstrate the accuracy of the method we analyze the isomerization of the alanine dipeptide in vacuum and the chair-to-inverted-chair transition of ?-D mannose in explicit water. Notwithstanding the simplicity of these systems, the SOMA approach reveals novel insights into the atomic mechanism of these isomerizations. In both cases, we find that the dynamics and the energetics of these processes are controlled by interactions involving only a handful of atoms in each molecule. Consistent with this result, we show that a coarse-grained SOMA calculation defined in terms of these subsets of atoms yields nearidentical minimum free-energy paths and committor distributions to those obtained via a highly-dimensional string. PMID:24729762

Branduardi, Davide; Faraldo-Gómez, José D.

2014-01-01

243

Neuroscience, Technology and Learning The 2nd STELLARnet Alpine RendezVous in the French Alps, 27th to 31st March 2011  

E-print Network

Neuroscience, Technology and Learning The 2nd STELLARnet Alpine RendezVous in the French Alps, 27th to 31st March 2011 White Paper arising from the workshop on: Neuroscience-6Aug2012 #12;Neuroscience, Technology and Learning 1.Introduction and motivation This workshop

Boyer, Edmond

244

Effects of beef enhancement with non-meat ingredients, blade tenderization, and vacuum tumbling on quality attributes of four beef cuts stored in a high oxygen environment  

E-print Network

(injected or non-injected), blade tenderization (0, 1, or 2 passes) and vacuum-tumbling (0, 5, 10 or 20 minutes). Injected muscles contained up to 10% of a brine containing 1.55% potassium lactate, 0.1% sodium diacetate, 0.3% sodium tripolyphosphate... evaluated steaks on day 1 only. Warner-Bratzler shear force (P<0.01) and trained sensory panel results (P<0.05) showed that the addition of non-meat ingredients improved tenderness in all four muscles. Sensory detectable connective tissue was lower (P<0...

Williams, Tracey Ann

2005-02-17

245

An Investigation of Multipath Effects on the GPS System During Auto-Rendezvous and Capture  

NASA Technical Reports Server (NTRS)

The proposed use of a Cargo Transport Vehicle (CTV) to carry hardware to the Space Station Freedom (SSF) during the construction phase of the SSF project requires remote maneuvering of the CTV. The CTV is not a manned vehicle. Obtaining the relative positions of the CTV and SSF for remote auto-rendezvous and capture (AR&C) scenarios will rely heavily on the Global Positioning System (GPS). The GPS system is expected to guide the CTV up to a distance of 100 to 300 meters from the SSF. At some point within this range, an optical docking system will take over the remote guidance for capture. During any remote guidance by GPS it is possible that significant multipath signals may be caused by large objects in the vicinity of the module being remotely guided. This could alter the position obtained by the GPS system from the actual position. Due to the nature of the GPS signals, it has been estimated that if the difference in distance between the Line of Sight (LOS) path and the multipath is greater than 300 meters, the GPS system is capable of discriminating between the direct signal and the reflected (or multipath) signal. However, if the path difference is less than 300 meters, one must be concerned. This report details the work accomplished by the Electromagnetic Simulations Laboratory at Marquette University over the period December 1993 to May 1995. This work is an investigation of the strength and phase of a multipath signal arriving at the CTV relative to the direct or line of sight (LOS) signal. The signal originates at a GPS satellite in half geo-stationary orbit and takes two paths to the CTV: (1) the direct or LOS path from the GPS satellite to the CTV; and (2) a scattered path from the GPS satellite to the SSF module and then to the CTV. The scattering from a cylinder has been computed using the physical optics approximation for the current. No other approximations or assumptions have been made including no assumptions regarding the far field or Fresnel field approximations. The integrations required to obtain the scattered field have been computed numerically using an N dimensional Romberg integration. The total scattered electric field is then projected onto the RCP component in the direction of propagation only. The direct or line of sight signal is then used to compute the relative strength and phase of the scattered field. The trajectory of the CTV has been parameterized into 4,214 points that are calculated for each of the geometries investigated. The motion of the CTV between points is small enough for the magnitude data (dB down from direct signal) to appear very smooth; however, because of the distances and wavelengths involved, the phase of the scattered field relative to the direct signal varies very rapidly.

Richie, James E.; Forest, Francis W.

1995-01-01

246

Laser rangefinder for the near-earth asteroid rendezvous (NEAR) mission  

NASA Astrophysics Data System (ADS)

The near-earth asteroid rendezvous (NEAR) mission is the first of the NASA discovery programs. Discovery-class programs emphasize small, low-cost, quick turnaround space missions that provide significant science returns. The NEAR spacecraft and ground control system are currently being developed and tested at the Applied Physics Laboratory (APL). The NEAR spacecraft will orbit, 433 Eros, possibly the most studied of the near-Earth asteroids. Subsequent to a 3-year cruise, the NEAR spacecraft is inserted into a 50-km-altitude orbit about Eros for 1 year to permit data collection in the infrared, visible, x-ray and gamma-ray regions. One instrument, the NEAR laser rangefinder (NLR), will provide altimetry data useful in characterizing the geophysical nature of Eros. In addition, ranging data from the NLR will support navigation functions associated with spacecraft station-keeping and orbit maintenance. The NLR instrument uniquely applies several technologies for use in space. Our configuration uses a direct-detection, bistatic design employing a gallium arsenide (GaAs) diode-pumped Cr:Nd:YAG laser for the 1.064-micrometer transmitter and an enhanced-silicon avalanche-photodiode (APD) detector for the receiver. Transmitter pulse energy provides the required signal-to-noise power ratio, SNRp, for reliable operation at 50 km. The selected APD exhibited low noise, setting the level achievable for noise equivalent power, NEP, by the receiver. The lithium-niobate (LiNbO3) Q-switched transmitter emits 12-ns pulses at 15.3 mJ/pulse, permitting reliable NLR operation beyond the required 50-km altitude. Cavity aperturing and a 9.3X Galilean telescope reduce beam divergence for high spatial sampling of Eros's surface. Our receiver design is an f/3.4 Dall-Kirkham Cassegrain with a 7.62-cm clear aperture -- we emphasized receiver aperture area, Arx, over transmitter power, Pt, in our design based on the range advantage attainable according to the simplified range equation, Rmax equals [(Pt(rho) BArx)/(SNRp NEP)]1/2. Asteroid reflectivity, (rho) B, is estimated to be 0.05 at our wavelength. A reasonable power signal- to-noise ratio for reliable operation, SNRp, was assumed. To minimize our noise equivalent power, NEP, we carefully designed and selected the receiver components. The receiver circuit uses leading-edge detection of the laser backscatter. Our detector circuit is an enhanced-silicon APD hybrid using a video amplifier, an integrating Bessel filter, and a high- speed programmable threshold comparator. We accomplish time-of-flight (TOF) measurements digitally with an APL-designed GaAs application-specific integrated circuit. A radiation-hardened FORTH microprocessor controls range gating, data collection and formatting, and operational modes. Implementation of control and data communications between the spacecraft and rangefinder uses the MIL-STD 1553-bus architecture. Functional testing and calibration indicate exceptional performance; return power levels were reliably detected over several thresholds with 71-dB attenuation, while observed range jitter was equivalent to the resolution determined by the TOF GaAs chip (31.5 cm). This paper discusses NLR performance requirements, design implementation, and qualification testing. It also provides preliminary results from calibration and performance testing.

Cole, Timothy D.; Boies, Mark T.; El-Dinary, Ashruf S.; Reiter, R. Alan; Rodriguez, Daniel E.; Heins, Robert J.; Le, Binh Q.; Moore, Robert C.; Grote, Michael G.; Culpepper, Charles; Stillman, Lee

1995-12-01

247

Modified technique of laparoendoscopic rendezvous ERCP during laparoscopic cholecystectomy for concomitant gallstone and common bile ductal stone.  

PubMed

Laparoendoscopic rendezvous ERCP and laparoscopic cholecystectomy (LC+ERCP/LERV) is considered an optimal approach for concomitant gallstone and common bile duct stone, but this procedure could be failed due to some technical challenges. We describe a modified technique which was adopted in 32 consecutive cases and yielded good results. A Dormia basket is inserted through cystic duct to enter duodenum and grasp the guide wire which is introduced with sphincterotome through endoscope. After pulling the basket catheter and guide wire into bile duct, the selective bile duct cannulation could be achieved by advancing sphinterotome over guide wire. An atraumatic clamp is also used to temporarily occlude proximal jejunum preventing diffuse bowel distention by air insufflation. The procedure was successfully performed in 31 cases(96.8%) , the mean operative time and endoscopic time were 82.6±19.6 min and 26.5±5.99min, respectively. This modified technique is safe, feasible and associated with short operative time. PMID:25436338

Liu, Wei; Wang, Qunwei; Huang, Jiangsheng; Liu, Luyao; Li, Pengfei; Xiao, Jing; Zhao, Liying

2014-09-01

248

Study of effects of uncertainties on comet and asteroid encounter and contact guidance requirements. Part 1: Guidance and navigation studies. [development of navigation and guidance techniques for space rendezvous  

NASA Technical Reports Server (NTRS)

A guidance algorithm that provides precise rendezvous in the deterministic case while requiring only relative state information is developed. A navigation scheme employing only onboard relative measurements is built around a Kalman filter set in measurement coordinates. The overall guidance and navigation procedure is evaluated in the face of measurement errors by a detailed numerical simulation. Results indicate that onboard guidance and navigation for the terminal phase of rendezvous is possible with reasonable limits on measurement errors.

1973-01-01

249

Tumble Wing Walkalong Glider  

NSDL National Science Digital Library

In this physics activity (page 2 of the PDF), learners will construct their own walkalong glider. They will explore how air, though invisible, surrounds and affects other objects. Learners will discover that air is made up of molecules that exert pressure on objects. Though this activity was created as a pre-visit for a traveling science show, it makes a great stand-alone activity as well.

COSI

2009-01-01

250

Magnetometer-Only Attitude and Rate Estimates for Spinning Spacecraft  

NASA Technical Reports Server (NTRS)

A deterministic algorithm and a Kalman filter for gyroless spacecraft are used independently to estimate the three-axis attitude and rates of rapidly spinning spacecraft using only magnetometer data. In-flight data from the Wide-Field Infrared Explorer (WIRE) during its tumble, and the Fast Auroral Snapshot Explorer (FAST) during its nominal mission mode are used to show that the algorithms can successfully estimate the above in spite of the high rates. Results using simulated data are used to illustrate the importance of accurate and frequent data.

Challa, M.; Natanson, G.; Ottenstein, N.

2000-01-01

251

The Space Operations Simulation Center (SOSC) and Closed-Loop Hardware Testing for Orion Rendezvous System Design  

NASA Technical Reports Server (NTRS)

The exploration goals of Orion / MPCV Project will require a mature Rendezvous, Proximity Operations and Docking (RPOD) capability. Ground testing autonomous docking with a next-generation sensor such as the Vision Navigation Sensor (VNS) is a critical step along the path of ensuring successful execution of autonomous RPOD for Orion. This paper will discuss the testing rationale, the test configuration, the test limitations and the results obtained from tests that have been performed at the Lockheed Martin Space Operations Simulation Center (SOSC) to evaluate and mature the Orion RPOD system. We will show that these tests have greatly increased the confidence in the maturity of the Orion RPOD design, reduced some of the latent risks and in doing so validated the design philosophy of the Orion RPOD system. This paper is organized as follows: first, the objectives of the test are given. Descriptions of the SOSC facility, and the Orion RPOD system and associated components follow. The details of the test configuration of the components in question are presented prior to discussing preliminary results of the tests. The paper concludes with closing comments.

Milenkovic, Zoran; DSouza, Christopher; Huish, David; Bendle, John; Kibler, Angela

2012-01-01

252

Coordinated Radio, Electron, and Waves Experiment (CREWE) for the NASA Comet Rendezvous and Asteroid Flyby (CRAF) instrument  

NASA Technical Reports Server (NTRS)

The Coordinated Radio, Electron, and Waves Experiment (CREWE) was designed to determine density, bulk velocity and temperature of the electrons for the NASA Comet Rendezvous and Asteroid Flyby Spacecraft, to define the MHD-SW IMF flow configuration; to clarify the role of impact ionization processes, to comment on the importance of anomalous ionization phenomena (via wave particle processes), to quantify the importance of wave turbulence in the cometary interaction, to establish the importance of photoionization via the presence of characteristic lines in a structured energy spectrum, to infer the presence and grain size of significant ambient dust column density, to search for the theoretically suggested 'impenetrable' contact surface, and to quantify the flow of heat (in the likelihood that no surface exists) that will penetrate very deep into the atmosphere supplying a good deal of heat via impact and charge exchange ionization. This final report provides an instrument description, instrument test plans, list of deliverables/schedule, flight and support equipment and software schedule, CREWE accommodation issues, resource requirements, status of major contracts, an explanation of the non-NASA funded efforts, status of EIP and IM plan, descope options, and Brinton questions.

Scudder, Jack D.

1992-01-01

253

Transgastric endoscopic rendezvous technique for removal of eroded Molina gastric band  

Microsoft Academic Search

The application of the nonadjustable gastric band (NAGB) for the treatment of morbid obesity was common in the 1980s. However, it was associated with an unacceptable reoperative rate and numerous postoperative complications such as gastric erosion. Removing an eroded NAGB is fraught with difficulty secondary to the extensive inflammatory response around the proximal stomach and left lobe of the liver.

Shahzeer Karmali; John F. Sweeney; Kimberly Yee; F. Charles Brunicardi; Vadim Sherman

2008-01-01

254

Graphical FPGA Design for a Predictive Controller with Application to Spacecraft Rendezvous  

E-print Network

)-based predictive controller based on Nesterov's fast gradient method is designed using Simulink and converted dynamics occuring over Ethernet. For a problem with 120 decision variables and 240 constraints, computation times of 0.95 ms are achieved with a clock rate of 50 MHz, corresponding to a speed up of more than 2000

Cambridge, University of

255

Technology Development of Automated Rendezvous and Docking/Capture Sensors and Docking Mechanism for the Asteroid Redirect Crewed Mission  

NASA Technical Reports Server (NTRS)

This paper will describe the technology development efforts NASA has underway for Automated Rendezvous and Docking/Capture (AR and D/C) sensors and a docking mechanism and the challenges involved. The paper will additionally address how these technologies will be extended to other missions requiring AR and D/C whether robotic or manned. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion crew vehicle. The commonality assessment also considered several future exploration and science missions requiring an AR and D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a threedimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build time instead of at design time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal nonrecurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR and D/C today. These sensor specifications are tightly coupled to the docking system capabilities and requirements for final docking conditions. The paper will describe NASA's efforts to develop a standard docking system for use across NASA human spaceflight missions to multiple destinations. It will describe the current design status and the considerations and technologies involved in developing this docking mechanism.

Hinkel, Heather; Strube, Matthew; Zipay, John J.; Cryan, Scott

2015-01-01

256

Technology Development of Automated Rendezvous and Docking/Capture Sensors and Docking Mechanism for the Asteroid Redirect Crewed Mission  

NASA Technical Reports Server (NTRS)

This paper will describe the technology development efforts NASA has underway for Automated Rendezvous and Docking/Capture (AR&D/C) sensors and a docking mechanism and the challenges involved. The paper will additionally address how these technologies will be extended to other missions requiring AR&D/C whether robotic or manned. NASA needs AR&D/C sensors for both the robotic and crewed segments of the Asteroid Redirect Mission (ARM). NASA recently conducted a commonality assessment of the concept of operations for the robotic Asteroid Redirect Vehicle (ARV) and the crewed mission segment using the Orion crew vehicle. The commonality assessment also considered several future exploration and science missions requiring an AR&D/C capability. Missions considered were asteroid sample return, satellite servicing, and planetary entry, descent, and landing. This assessment determined that a common sensor suite consisting of one or more visible wavelength cameras, a threedimensional LIDAR along with long-wavelength infrared cameras for robustness and situational awareness could be used on each mission to eliminate the cost of multiple sensor developments and qualifications. By choosing sensor parameters at build time instead of at design time and, without having to requalify flight hardware, a specific mission can design overlapping bearing, range, relative attitude, and position measurement availability to suit their mission requirements with minimal nonrecurring engineering costs. The resulting common sensor specification provides the union of all performance requirements for each mission and represents an improvement over the current systems used for AR&D/C today. These sensor specifications are tightly coupled to the docking system capabilities and requirements for final docking conditions. The paper will describe NASA's efforts to develop a standard docking system for use across NASA human spaceflight missions to multiple destinations. It will describe the current design status and the considerations and technologies involved in developing this docking mechanism.

Hinkel, Heather; Cryan, Scott; Zipay, John; Strube, Matthew

2015-01-01

257

Tumbling motions of [NH2(CH3)2]+ ions in [NH2(CH3)2]2CoCl4 determined by 1H MAS NMR spectroscopy in the rotating frame  

NASA Astrophysics Data System (ADS)

The structure and phase transition temperatures of [NH2(CH3)2]2CoCl4 were determined using X-ray diffraction and differential scanning calorimetry, respectively. The temperature dependence of chemical shifts and the spin-lattice relaxation time T1? in the rotating frame were measured for the 1H nucleus in [NH2(CH3)2]2CoCl4. T1? for 1H in [NH2(CH3)2]2CoCl4 showed a minimum, and it is apparent that T1? values are governed by a tumbling motion. The activation energy of tumbling motion for 1H is owing to the interaction between CH3 and NH2 ions in the [NH2(CH3)2]+ group.

Yoon, Ma Byong; Bong, Pill Hoon; Lim, Ae Ran

2015-03-01

258

Analysis of control accuracy in the final phase of the rendezvous between the Automated Transfer Vehicle and the Space Station Freedom  

NASA Astrophysics Data System (ADS)

The Automated Transfer Vehicle (ATV) is an expendable unmanned vehicle launched by Ariane 5. The ATV's reference mission is to support the Space Station Freedom (SSF). The ascent part of the ATV's mission is to reach a given berthing point next to the SSF, within required accuracies. The vehicle must be able to hold this position in order to be grappled by the SSF's robotic arm. With the SSF's monitoring and authorizations, the ATV is designed to be able to achieve automatic rendezvous operations within the SSF's manned environment. During the final approach, the ATV's motion is a forced translation parallel to the SSF velocity axis. The control accuracy, estimated around this reference trajectory, is a key parameter for respect of safety requirements, and the purpose for this paper. After a brief description of the ATV's reference mission, we will focus on the last 100 meters of the rendezvous between the ATV and the SSF. We will begin by describing the modeling principles and the simplifying assumptions used to obtain a dynamic model for the relative distance between the ATV and SSF berthing points. The principles of the ATV rendezvous optical sensor and thruster architecture will also be discussed. The design of a control aimed at maintaining the reference trajectory will next be considered along with the effects of measurement and modeling disturbances, noise as well as bias, on the control accuracy. The results demonstrate that the accuracy achieved around the reference trajectory remains compliant with the berthing requirements and would even allow direct docking if needed.

Clar, Philippe G.; Theillier, Francis; Triou, Henri

259

Spontaneous Rupture of Superficial Femoral Artery Repaired with Endovascular Stent-Grafting with use of Rendez-Vous Technique, Followed by Delayed Infection  

SciTech Connect

This is the case of a 72-year-old man with lower limb ischemia due to spontaneous rupture of nonaneurysmal superficial femoral artery that developed into thigh hematoma. After failure of a Fogarty revascularization, an emergency endovascular procedure was performed to restore the arterial continuity. A rendezvous procedure was performed with a double femoral and popliteal approach and two covered stent-grafts were deployed. Patient's clinical conditions immediately improved, but 4 months later the stent-grafts were surgically removed for infection and exteriorization. A femoropopliteal bypass was performed. After 1 year follow-up, the patient is in good clinical condition.

Fanelli, Fabrizio, E-mail: fabrizio.fanelli@uniroma1.it; Cannavale, Alessandro [University of Rome 'Sapienza,', Department of Radiological Sciences, Vascular and Interventional Radiology Unit (Italy)] [University of Rome 'Sapienza,', Department of Radiological Sciences, Vascular and Interventional Radiology Unit (Italy); Gazzetti, Marianna [Sapienza University of Rome 'Sapienza,', Department of Surgery Paride Stefanini, Vascular Surgery Division, Policlinico Umberto I (Italy)] [Sapienza University of Rome 'Sapienza,', Department of Surgery Paride Stefanini, Vascular Surgery Division, Policlinico Umberto I (Italy); Fantozzi, Cristiano; Taurino, Maurizio [University of Rome 'Sapienza,', Department of Vascular Surgery (Italy)] [University of Rome 'Sapienza,', Department of Vascular Surgery (Italy); Speziale, Francesco [Sapienza University of Rome 'Sapienza,', Department of Surgery Paride Stefanini, Vascular Surgery Division, Policlinico Umberto I (Italy)] [Sapienza University of Rome 'Sapienza,', Department of Surgery Paride Stefanini, Vascular Surgery Division, Policlinico Umberto I (Italy)

2013-02-15

260

A Modified Technique Reduced Operative Time of Laparoendoscopic Rendezvous Endoscopic Retrograde Cholangiopancreatography Combined with Laparoscopic Cholecystectomy for Concomitant Gallstone and Common Bile Ductal Stone  

PubMed Central

Laparoendoscopic rendezvous (LERV) endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic cholecystectomy (LC+ERCP/LERV) are considered an optimal approach for concomitant gallstones and common bile duct stones. The rendezvous technique is essential for the success of procedure. We applied two different LERV techniques, traditional technique and modified technique, in 60 consecutive cases from January 2011 to November 2012. 32 cases who underwent modified technique (group 1) from February 2012 to November 2012 were retrospectively compared to 28 cases (group 2) who underwent traditional technique from January 2011 to January 2012. There was no significant difference between two groups with respect to preoperative demographic features. Although the difference was not statistically significant, the procedure was successfully performed in 31 cases (96.9%) in group 1 and 24 cases (86.2%) in group 2. The mean operative time and time of endoscopic part were 82.6?±?19.6?min and 26.5?±?5.99?min in group 1 which were significantly shorter than those in group 2 (118.0?±?23.1?min and 58.7?±?13.3?min, resp.). There was no postoperative pancreatitis and mortality in both groups. The mean hospital stay, blood loss, incidence of complications, and residual stone were of no difference in both groups. This study proved that this modified technique can effectively reduce the operative time and time of endoscopic part of LC+ERCP/LERV compared with traditional technique. PMID:25024701

Liu, Wei; Wang, Qunwei; Xiao, Jing; Zhao, Liying; Huang, Jiangsheng; Tan, Zhaohui; Li, Pengfei

2014-01-01

261

Source : Philippe Poirrier, Culture populaire et politique culturelle en France : un rendez-vous manqu ? dans Thomas ANTONIETTI, Bruno MEIER et Katrin RIEDER (dir.), Retour vers le prsent. La culture populaire en Suisse, Baden,  

E-print Network

Source : Philippe Poirrier, « Culture populaire et politique culturelle en France : un rendez culture populaire en Suisse, Baden, Hier+jetzt, Verlag für Kultur und Geschichte, 2008, p. 176-183. Culture populaire et politique culturelle en France : un rendez-vous manqué ? Comment la politique

Paris-Sud XI, Université de

262

Star Library: Random Rendezvous  

NSDL National Science Digital Library

This activity leads students to appreciate the usefulness of simulations for approximating probabilities. It also provides them with experience calculating probabilities based on geometric arguments and using the bivariate normal distribution. We have used it in courses in probability and mathematical statistics, as well as in an introductory statistics course at the post-calculus level. Students are expected to approximate the solution through simulation before solving it exactly. They are also expected to employ graphical as well as algebraic problem-solving strategies, in addition to their simulation analyzes. Finally, students are asked to explain intuitively why it makes sense for the probabilities to change as they do.

Chance, Beth; Rossman, Allan

2009-06-04

263

Mountain Man Measurement Rendezvous  

NSDL National Science Digital Library

In this math lesson, learners participate in several activities where they apply measurement skills. Learners explore how the Mountain Men played an important part in the history of the American frontier and more importantly, how the Mountain Men used different techniques for making measurements in their daily activities. At the various stations, learners measure their jump distances, handfuls of "gold," water-soaked sponges, "buffalo chip" throws, arm spans, "stone" throws, "arrow" tosses, foot sizes, pots of beans, and "shooting" distances. This activity works well outside.

Lessonplans, Utah

2012-10-22

264

Investigation of the Spinning and Tumbling Characteristics of a 1/25-Scale Model of the Lockheed XFV-1 Airplane in the Langley 20-Foot Free-Spinning Tunnel  

NASA Technical Reports Server (NTRS)

An investigation has been conducted in the Langley 20-foot free-spinning tunnel on a l/23-scale model of the Lockheed XFV-1 airplane to determine the effects of control setting and movement upon the erect-spin and recovery characteristics for a range of airplane loading conditions. A windmilling propeller was simulated on the model for some of the tests. The investigation included determination of the size of tail parachute required for emergency recovery from demonstration spins. The tumbling tendencies of the model were also investigated. The results indicated that any erect or inverted spin obtained on the airplane will be satisfactorily terminated if recovery is attempted by full rudder reversal accompanied by simultaneous lateral and longitudinal movement of the stick to neutral, The model test results showed that an 11.5-foot flat-type tail parachute (drag coefficient approximately 0.73) with a 27.5-foot towline will be effective as an emergency spin-recovery device during demonstration spins of the airplane. The model results also indicate that the airplane will not tumble for any.loading condition indicated possible.

Lee, Henry A.

1953-01-01

265

Tumbling Creek Cavesnail Recovery Plan  

E-print Network

Haven Rd. Columbia, MO 65201 573-876-1818 john_besser@usgs.gov Bruce Caldwell* U.S. Army Corps of Engineers 324 W. 7th St. Mountain Home, AR 72653 870-425-2700, ext. 125 bruce.w.caldwell@usace.army.mil Theresa Davidson* U.S. Fish and Wildlife Service 1103 S. Jefferson Ava, MO 65608 417-683-4428 theresa_davidson

Taylor, Steven J.

266

Investigation of Spinning and Tumbling Characteristics of a 1/20-Scale Model of the Consolidated Vultee XFY-1 Airplane in the Free-Spinning Tunnel, TED No. NACA DE 370  

NASA Technical Reports Server (NTRS)

An investigation has been conducted in the Langley 20-foot free-spinning tunnel on a l/20-scale model of the Consolidated Vultee XFY-1 airplane with a windmilling propeller simulated to determine the effects of control setting and movements upon the erect spin and recovery characteristics for a range of airplane-loading conditions. The effects on the model's spin-recovery characteristics of removing the lower vertical tail, removing the gun pods, and fixing the rudders at neutral were also investigated briefly. The investigation included determination of the size parachute required for emergency recovery from demonstration spins. The tumbling tendencies of the model were also investigated. Brief static force tests were made to determine the aerodynamic characteristics in pitch at high angles of attack. The investigation indicated that the spin and recovery characteristics of the airplane with propeller windmilling will be satisfactory for all loading conditions if recovery is attempted by full rudder reversal accompanied by simultaneous movement of the stick laterally to full with the spin (stick right in a right spin) and longitudinally to neutral. Inverted spins should be satisfactorily terminated by fully reversing the rudder followed immediately by moving the stick laterally towards the forward rudder pedal and longitudinally to neutral. Removal of the gun pods or fixing the rudders at neutral will not adversely affect the airplane's spin-recovery characteristics, but removal of the lower vertical tail will result in unsatisfactory spin-recovery characteristics. The model-test results showed that a 13.3-foot wing-tip conventional parachute (drag coefficient approximately 0.7) should be effective as an emergency spin-recovery device during demonstration spins of the airplane. It was indicated that the airplane should not tumble and that no unusual longitudinal-trim characteristics should be obtained for the center-of-gravity positions investigated.

Lee, Henry A.

1952-01-01

267

Growth Rate  

NSDL National Science Digital Library

This lesson from Illuminations uses growth charts for girls and boys to examine rates of change. The material uses slope to approximate the rate of change in height. Students will learn how to translate this data into a graph. The lesson is appropriate for grades 9-12 and should require 1 class period to complete.

2011-01-14

268

A Proposed Strategy for the U.S. to Develop and Maintain a Mainstream Capability Suite ("Warehouse") for Automated/Autonomous Rendezvous and Docking in Low Earth Orbit and Beyond  

NASA Technical Reports Server (NTRS)

The ability of space assets to rendezvous and dock/capture/berth is a fundamental enabler for numerous classes of NASA fs missions, and is therefore an essential capability for the future of NASA. Mission classes include: ISS crew rotation, crewed exploration beyond low-Earth-orbit (LEO), on-orbit assembly, ISS cargo supply, crewed satellite servicing, robotic satellite servicing / debris mitigation, robotic sample return, and robotic small body (e.g. near-Earth object, NEO) proximity operations. For a variety of reasons to be described, NASA programs requiring Automated/Autonomous Rendezvous and Docking/Capture/Berthing (AR&D) capabilities are currently spending an order-of-magnitude more than necessary and taking twice as long as necessary to achieve their AR&D capability, "reinventing the wheel" for each program, and have fallen behind all of our foreign counterparts in AR&D technology (especially autonomy) in the process. To ensure future missions' reliability and crew safety (when applicable), to achieve the noted cost and schedule savings by eliminate costs of continually "reinventing the wheel ", the NASA AR&D Community of Practice (CoP) recommends NASA develop an AR&D Warehouse, detailed herein, which does not exist today. The term "warehouse" is used herein to refer to a toolbox or capability suite that has pre-integrated selectable supply-chain hardware and reusable software components that are considered ready-to-fly, low-risk, reliable, versatile, scalable, cost-effective, architecture and destination independent, that can be confidently utilized operationally on human spaceflight and robotic vehicles over a variety of mission classes and design reference missions, especially beyond LEO. The CoP also believes that it is imperative that NASA coordinate and integrate all current and proposed technology development activities into a cohesive cross-Agency strategy to produce and utilize this AR&D warehouse. An initial estimate indicates that if NASA strategically coordinates the development of a robust AR&D capability across the Agency, the cost of implementing AR&D on a spacecraft could be reduced from roughly $70M per mission to as low as $7M per mission, and the associated development time could be reduced from 4 years to 2 years, after the warehouse is completely developed. Table 1 shows the clear long-term benefits to the Agency in term of costs and schedules for various missions. (The methods used to arrive at the Table 1 numbers is presented in Appendices A and B.)

Krishnakumar, Kalmanje S.; Stillwater, Ryan A.; Babula, Maria; Moreau, Michael C.; Riedel, J. Ed; Mrozinski, Richard B.; Bradley, Arthur; Bryan, Thomas C.

2012-01-01

269

Tumbling: From Rally Cars to Toast  

ERIC Educational Resources Information Center

The article by Rod Cross describing the translational and rotational motion of the "Launch of a Vehicle from a Ramp" motivated us to create two computer models showing this type of dynamical behavior.

Belloni, Mario; Christian, Wolfgang

2012-01-01

270

Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics  

NASA Technical Reports Server (NTRS)

This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR, and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time as well as the ability to intervene using manual override to teleoperate the robot.

Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

2009-01-01

271

The gas production rate of periodic comet d'Arrest  

NASA Technical Reports Server (NTRS)

Comet P/d'Arrest is a potential target for a rendezvous mission to a short period comet. Its light curve is rather peculiar, the comet being active only after perihelion passage. One apparition out of two is easy to observe from the ground. The 1995 apparition of the comet will offer a unique opportunity to characterize the outgassing properties of its nucleus.

Festou, Michel C.; Feldman, Paul D.; Ahearn, Michael F.

1992-01-01

272

75 FR 44794 - Rendezvous International v.  

Federal Register 2010, 2011, 2012, 2013, 2014

...released only upon presentation by Respondents of Original endorsed Negotiable Bills of Lading. The payment terms were on a CAD (Cash Against Documents) basis.'' Complainant alleges that the terms of the Bill of Lading were ``violated by...

2010-07-29

273

Mars Researchers Rendezvous on Remote Arctic Island  

NASA Technical Reports Server (NTRS)

Devon Island is situated in an isolated part of Canada's Nunavut Territory, and is usually considered to be the largest uninhabited island in the world. However, each summer since 1999, researchers from NASA's Haughton-Mars Project and the Mars Society reside at this 'polar desert' location to study the geologic and environmental characteristics of a site which is considered to be an excellent 'Mars analog': a terrestrial location wherein specific conditions approximate environmental features reported on Mars. Base camps established amidst the rocks and rubble surrounding the Haughton impact crater enable researchers to conduct surveys designed to test the habitat, equipment and technology that may be deployed during a human mission to Mars. One of the many objectives of the project scientists is to understand the ice formations around the Haughton area, in the hopes that this might ultimately assist with the recognition of areas where ice can be found at shallow depth on Mars.

These images of Devon Island from NASA's Multi-angle Imaging SpectroRadiometer (MISR) instrument provide contrasting views of the spectral and angular reflectance 'signatures' of different surfaces within the region. The top panel is a natural color view created with data from the red, green and blue-bands of MISR's nadir (vertical-viewing) camera. The bottom panel is a false-color multiangular composite of the same area, utilizing red band data from MISR's 60-degree backward, nadir, and 60-degree forward-viewing cameras, displayed as red, green and blue, respectively. In this representation, colors highlight textural properties of elements within the scene, with blue tones indicating smooth surfaces (which preferentially forward scatter sunlight) and red hues indicating rougher surfaces (which preferentially backscatter). The angular reflectance 'signature' of low clouds causes them to appear purple, and this visualization provides a unique way of distinguishing clouds from snow and ice.

The data were captured on June 28, 2001, during the early part of the arctic summer, when sea ice becomes thinner and begins to move depending upon localized currents and winds. In winter the entire region is locked with several meters of nearly motionless sea ice, which acts as a thermodynamic barrier to the loss of heat from the comparatively warm ocean to the colder atmosphere. Summer melting of sea ice can be observed at the two large, dark regions of open water; one is present in the Jones Sound (near the top to the left of center), and another appears in the Wellington Channel (left-hand edge). A large crack caused by tidal heaving has broken the ice cover over the Parry Channel (lower right-hand corner). A substantial ice cap permanently occupies the easternmost third of the island (upper right). Surface features such as dendritic meltwater channels incised into the island's surface are apparent. The Haughton-Mars project site is located slightly to the left and above image center, in an area which appears with relatively little surface ice, near the island's inner 'elbow.'

The images were acquired during Terra orbit 8132 and cover an area of about 334 kilometers x 229 kilometers. They utilize data from blocks 27 to 31 within World Reference System-2 path 42.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

2002-01-01

274

Near Earth Asteroid Rendezvous - A Pictorial Voyage  

NSDL National Science Digital Library

This site offers students an opportunity to participate in a pictorial voyage that follows the NEAR spacecraft from its inception through the cruise phase to asteroid 433 Eros. They will learn about the rationale for visiting an asteroid, the instruments and construction of the spacecraft, and follow its flyby of the asteroid Mathilde, swingby of Earth, and encounter with Eros.

275

14 CFR 1214.111 - Rendezvous services.  

Code of Federal Regulations, 2014 CFR

...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange of a spacecraft (or part thereof) delivered to orbit on a particular Space Shuttle mission for an already orbiting spacecraft (or part thereof) and return of already...

2014-01-01

276

14 CFR 1214.111 - Rendezvous services.  

Code of Federal Regulations, 2013 CFR

...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange of a spacecraft (or part thereof) delivered to orbit on a particular Space Shuttle mission for an already orbiting spacecraft (or part thereof) and return of already...

2013-01-01

277

14 CFR 1214.111 - Rendezvous services.  

Code of Federal Regulations, 2010 CFR

...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange of a spacecraft (or part thereof) delivered to orbit on a particular Space Shuttle mission for an already orbiting spacecraft (or part thereof) and return of already...

2010-01-01

278

14 CFR 1214.111 - Rendezvous services.  

Code of Federal Regulations, 2011 CFR

...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange of a spacecraft (or part thereof) delivered to orbit on a particular Space Shuttle mission for an already orbiting spacecraft (or part thereof) and return of already...

2011-01-01

279

14 CFR 1214.111 - Rendezvous services.  

Code of Federal Regulations, 2012 CFR

...spacecraft deployed earlier on the same Space Shuttle flight. (2) Exchange of a spacecraft (or part thereof) delivered to orbit on a particular Space Shuttle mission for an already orbiting spacecraft (or part thereof) and return of already...

2012-01-01

280

Long range targeting for space based rendezvous  

NASA Technical Reports Server (NTRS)

The work performed under this grant supported the Dexterous Flight Experiment one STS-62 The project required developing hardware and software for automating a TRAC sensor on orbit. The hardware developed by for the flight has been documented through standard NASA channels since it has to pass safety, environmental, and other issues. The software has not been documented previously, therefore, this report provides a software manual for the TRAC code developed for the grant.

Everett, Louis J.; Redfield, R. C.

1995-01-01

281

Mathilde Encounter: Near Earth Asteroid Rendezvous  

NSDL National Science Digital Library

In one of the most successful flybys of all time, the NEAR spacecraft passed within 1200 km of asteroid 253 Mathilde on June 27. Johns Hopkins University Applied Physics Laboratory has created a website to document this event. The site contains information on the NEAR mission objectives, science goals, and Mathilde itself. It also features images of the asteroid, a flyby simulation, and an MPEG movie (player download provided).

1997-01-01

282

Discovery: Near-Earth Asteroid Rendezvous (NEAR)  

NASA Technical Reports Server (NTRS)

The work carried out under this grant consisted of two parallel studies aimed at defining candidate missions for the initiation of the Discovery Program being considered by NASA's Solar System Exploration Division. The main study considered a Discover-class mission to a Near Earth Asteroid (NEA); the companion study considered a small telescope in Earth-orbit dedicated to ultra violet studies of solar system bodies. The results of these studies are summarized in two reports which are attached (Appendix 1 and Appendix 2).

Veverka, Joseph

1992-01-01

283

Operator learning effects in teleoperated rendezvous & docking  

NASA Astrophysics Data System (ADS)

Teleoperation of spacecraft proximity operations and docking requires delicate timing and coordination of spacecraft maneuvers. Experience has shown that human operators show large performance fluctuations in these areas, which are a major factor to be addressed in operator training. In order to allow the quantification of the impact of these human fluctuations on control system performance and the human perception of this performance, a learning curve study was conducted with teleoperated final approach and docking scenarios. Over a period of ten experiment days, three test participants were tasked with repeatedly completing a set of three training scenarios. The scenarios were designed to contain different combinations of the major elements of any final approach and docking situation, and to feature an increasing difficulty level. The individual difficulty levels for the three operators furthermore differed in the level of operator support functions available in their human-machine interfaces. Operator performance in the test scenarios were evaluated in the fields approach success and precision, docking safety, and approach efficiency by a combination of recorded maneuver data and questionnaires. The results show that operator experience and the associated learning curves increase operator performance substantially, regardless of the support system used. The paper also shows that the fluctuations in operator performance and self-perception are substantial between as well as within experiment days, and must be reckoned with in teleoperation system design and mission planning.

Wilde, M.; Harder, J.; Purschke, R.

284

A Miniature, High-Resolution Laser Radar Operating at Video Rates  

SciTech Connect

The authors are developing a laser radar to meet the needs of NASA for a 5-lb, 150 in{sup 3} image sensor with a pixel range accuracy of 0.1-inch. NASA applications include structural dynamics measurements, navigation guidance in rendezvous and proximity operations, and space vehicle inspection. The sensor is based on the scannerless range imager architecture developed at Sandia. This architecture modulates laser floodlight illumination and a focal plane receiver to phase encode the laser time of flight (TOF) for each pixel. They believe this approach has significant advantages over architectures directly measuring TOF including high data rate, reduced detector bandwidth, and conventional FPA detection. A limitation of the phase detection technique is its periodic nature, which provides relative range information over a finite ambiguity interval. To extend the operating interval while maintaining a given range resolution, a LADAR sensor using dual modulation frequencies has been developed. This sensor also extends the relative range information to absolute range by calibrating a gating function on the receiver to the TOF. The modulation frequency values can be scaled to meet the resolution and range interval requirements of different applications. Results from the miniature NASA sensor illustrate the advantages of the dual-frequency operation and the ability to provide the range images of 640 by 480 pixels at 30 frames per second.

SMITHPETER,COLIN L.; NELLUMS,ROBERT O.; LEBIEN,STEVEN M.; STUDOR,GEORGE

2000-06-26

285

Injury patterns and rates amongst students at the national institute of circus arts: an observational study.  

PubMed

Despite the ever-growing global participation in circus arts, very little research has been conducted into injuries associated with this physical discipline. To date, no studies have examined the incidence of injuries in circus training institutions and schools. In this study, data were collected over an academic year from all student injury presentations to the physiotherapy staff at one Australian circus school. A total of 351 injuries resulting in 1,948 treatments occurred in 33 female and 30 male circus students. The most common mechanisms of injury were acrobatics/tumbling (23%), handstands (12%), adagio (11%), and Chinese pole (10%). The most commonly injured body parts were the ankle (25%), lumbar spine (14%), and shoulder (12%). Interestingly, combined spinal injuries (cervical, thoracic, and lumbar) contributed to 35% of all initial injuries. Females sustained 71% of all hip injuries, but only 33% of all forearm injuries. Males accounted for 59% of all ankle injuries. There were no significant gender-based differences in other body areas. Results indicated that there is no gender-based difference in the overall rate of injury. However, females sustained significantly higher rates of hip injuries and males presented with more forearm and ankle injuries, perhaps reflecting the specific form and style of circus training and contortion undertaken. Spinal injuries had the highest overall rate of initial and follow-up presentations, indicating that both preventative and rehabilitative strategies could be addressed. It is suggested that the most common mechanisms of injury reflect both the amount of time spent training specific disciplines and the extreme physical difficulties and demands placed on the body. PMID:25433261

Munro, David

2014-12-01

286

Experimental attrition rates of bed-material sediment from geologic provinces of Western Oregon and their application to regional sediment models  

NASA Astrophysics Data System (ADS)

Many topographic, hydrologic, and land use variables affect the supply and transport of bed-material in rivers, but the underlying geology is a key factor controlling both the volume of introduced material and the attrition of bed-material as it moves downstream. Recent and ongoing USGS river studies in Western Oregon document strong links between geologic province and bed-material transport. Rivers originating in the Mesozoic metamorphic and intrusive igneous rocks of the Klamath terranes of southwestern Oregon have the greatest gravel transport rates (and channel and valley-bottom morphologies reflecting high bed-material fluxes), whereas the generally lesser amounts of gravel in streams that drain Oregon's Coast Range and western Cascade Range owes in large part to Tertiary sedimentary and volcanic units underlying most of these basins. Aspects of these differences are controlled by supply as well as clast attrition. Here we aim to quantify bed-material attrition rates associated with the five main geologic provinces of Western Oregon: the Klamath terranes, Western Cascades, High Cascades, Coast Range sedimentary rocks, and Coast Range volcanic rocks. Bed-material samples were collected throughout the region from streams that drain a single geologic province and tumbled with a lapidary tumbler to determine relative attrition rates. Two kilograms of each sample were sorted into an initial distribution of clast sizes (from 16 to 64mm) and tumbled, with periodic breaks to reweigh and sieve the sample. Results show marked differences in attrition rates, with the sedimentary rocks of the Coast Range having weight loss coefficients between 1.206 and 0.211/km, orders of magnitude greater than all of the other sampled provinces. For comparison, bed material from the Klamath terranes have weight loss coefficients ranging from 0.013 to 0.005/km, and a control sample of quartzite clasts (from the Klamath terranes) has a weight loss coefficient of 0.001/km. These results confirm that bed-material attrition is an important process affecting bed-material supply and transport, and will allow for more complete development of regional bed-material sediment budgets in ongoing efforts to understand patterns of gravel abundance and channel morphology in rivers of Western Oregon.

Mangano, J.; O'Connor, J. E.; Jones, K. L.; Wallick, R.

2011-12-01

287

Evaporation Rate on Tungsten  

E-print Network

Cesium Evaporation Rate on Tungsten Photocathodes Ameerah Jabr-Hamdan Introduction Motivation Research Objective Experiments Results Conclusions Cesium Evaporation Rate on Tungsten Photocathodes supported by IREAP, with funding from NSF and ONR #12;Cesium Evaporation Rate on Tungsten Photocathodes

Anlage, Steven

288

MPAA Ratings Creep  

Microsoft Academic Search

The term “ratings creep” refers to the belief that various types of adult content escalate in films with the same rating over time. The purpose of this study was to test the ratings creep hypothesis through a quantitative analysis of films from 1988, 1997, and 2006 in the PG-13 rating category used by the Motion Picture Association of America (MPAA).

Ron Leone; Laurie Barowski

2011-01-01

289

Calculating Divorce Rates  

NSDL National Science Digital Library

This exercise from a course in family sociology asseses students' ability to interpret divorce rates from provided spreadsheet data and to critically analyze three articles that use divorce rates in their content.

Joseph Carroll

290

[The resting heart rate].  

PubMed

Assessment of resting heart rate is frequently performed and is easy, reliable and inexpensive. Heart rate is used in many algorithms to assess the prognosis of acutely ill patients. Elevated resting heart rate is independently related to the development of type 2 diabetes, cardiovascular disease and premature all-cause mortality. Adding heart rate to cardiovascular prediction models does not lead to improved prediction of vascular events or mortality. Beta blockers and non-dihydropyridine calcium channel blockers decrease heart rate (and blood pressure) and lower the risk of premature mortality in patients with heart failure or recent myocardial infarction. In two recent randomised trials, ivabradine specifically decreased heart rate (but not blood pressure) and the risk of cardiovascular events in patients with heart failure or coronary artery disease, decreased left ventricular function and resting heart rate of ? 70 beats/minute. Selective heart rate reduction is a potential treatment option to decrease cardiovascular risk. PMID:24666528

Bemelmans, Remy H H; Visseren, Frank L J

2014-01-01

291

Movie Rating Prediction  

Microsoft Academic Search

The Internet Movie Database (IMDB) is one of the largest online resources for general movie information combined with a forum in which users can rate movies. We investigate the extent to which a movie's average user rating can be predicted after learning the relationship between the rating and a movie's various attributes from a training set. Two methods are evaluated:

Armstrong Nick; Kevin Yoon

292

Handbook of noise ratings  

NASA Technical Reports Server (NTRS)

The handbook was compiled to provide information in a concise form, describing the multitude of noise rating schemes. It is hoped that by describing the noise rating methods in a single volume the user will have better access to the definitions, application and calculation procedures of the current noise rating methods.

Pearsons, K. S.; Bennett, R. L.

1974-01-01

293

Rate theories for biologists  

PubMed Central

Some of the rate theories that are most useful for modeling biological processes are reviewed. By delving into some of the details and subtleties in the development of the theories, the review will hopefully help the reader gain a more than superficial perspective. Examples are presented to illustrate how rate theories can be used to generate insight at the microscopic level into biomolecular behaviors. Attempt is made to clear up a number of misconceptions in the literature regarding popular rate theories, including the appearance of Planck’s constant in the transition-state theory and the Smoluchowski result as an upper limit for protein-protein and protein-DNA association rate constants. Future work in combining the implementation of rate theories through computer simulations with experimental probes of rate processes, and in modeling effects of intracellular environments so theories can be used for generating rate constants for systems biology studies is particularly exciting. PMID:20691138

Zhou, Huan-Xiang

2012-01-01

294

Observed Barium Emission Rates  

NASA Technical Reports Server (NTRS)

The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

1993-01-01

295

Vesicle tumbling inhibited by inertia Aymen Laadhari,1  

E-print Network

circulatory system the Reynolds number (at the scale of the RBC) is not always small enough for the Stokes constitute a model system for the study of red blood cells (RBCs) dynamics and blood rheology. In the blood,8 correspond to the very small Reynolds numbers limit. However, in the blood circulatory sys- tem, especially

Paris-Sud XI, Université de

296

Take a Tumble: Weathering and Erosion Using a Rock Tumbler  

NSDL National Science Digital Library

The subtle effects of weathering and erosion are difficult to convey to students. However, through this activity, students can use a rock tumbler to gain a personal and scientific perspective on weather and erosion. Students have the opportunity to demonstrate their understanding of these concepts and work with geologic materials as they make predictions and measurements, record data, and do simple calculations (McKnight 1989).

Patrick Coffey

2006-03-01

297

Run-and-tumble particles in speckle fields.  

PubMed

The random energy landscapes developed by speckle fields can be used to confine and manipulate a large number of micro-particles with a single laser beam. By means of molecular dynamics simulations, we investigate the static and dynamic properties of an active suspension of swimming bacteria embedded into speckle patterns. Looking at the correlation of the density fluctuations and the equilibrium density profiles, we observe a crossover phenomenon when the forces exerted by the speckles are equal to the bacteria's propulsion. PMID:25105250

Paoluzzi, M; Di Leonardo, R; Angelani, L

2014-09-17

298

Failed Escape: Solid Surfaces Prevent Tumbling of Escherichia coli  

E-print Network

Understanding how bacteria move close to surfaces is crucial for a broad range of microbial processes including biofilm formation, bacterial dispersion, and pathogenic infections. We used digital holographic microscopy to ...

Molaei, Mehdi

299

Take a Tumble: Weathering and Erosion Using a Rock Tumbler  

ERIC Educational Resources Information Center

Weathering--the physical and chemical breakdown of geologic materials--and erosion--the transport of materials by wind, water, or ice--can be subtle, yet powerful forces. For example, shale, a rock made of mud-sized particles, is by far the most common sedimentary rock, a testament to the ability of weathering and erosion to take a rock and reduce…

Coffey, Patrick; Mattox, Steve

2006-01-01

300

NOAA -14 September 28, 2006 (DOY 271) tumble anomaly  

Microsoft Academic Search

This describes a NOAA-14 spacecraft loss of control event and the lessons learned. The lessons learned are in two categories: contingency recovery operations; and on-orbit propulsion system isolation methods. The work is motivated in recognition of the effort of the NOAA off-line engineering support team and their NOAA civil servant mission leads and operations support staff.

M. Phenneger; J. Woodward; R. Cox; C. Gliniak

2008-01-01

301

The NOAA -14 September 28, 2006(DOY271) Tumble Anomaly  

Microsoft Academic Search

This paper describes a NOAA-14 spacecraft loss of control event and the lessons learned from it. The lessons learned are in two categories; contingency recovery operations and on-orbit propulsion system isolation methods. The work is motivated in recognition of the effort of the NOAA off-line engineering support team and their NOAA civil servant mission leads and operations support staff.

M. C. Phenneger; J. Woodward; R. Cox; C. Gliniak

2008-01-01

302

Run-and-tumble particles in speckle fields  

E-print Network

The random energy landscapes developed by speckle fields can be used to confine and manipulate a large number of micro-particles with a single laser beam. By means of molecular dynamics simulations, we investigate the static and dynamic properties of an active suspension of swimming bacteria embedded into speckle patterns. Looking at the correlation of the density fluctuations and the equilibrium density profiles, we observe a crossover phenomenon when the forces exerted by the speckles are equal to the bacteria's propulsion.

M. Paoluzzi; R. Di Leonardo; L. Angelani

2014-06-10

303

Grinding media oscillation: effect on torsional vibrations in tumble mills  

E-print Network

speeds using a gear reduction unit and often have vibration problems. These vibration problems result in increased gear wear and occasional catastrophic failures resulting in production loss. The objective of this research is to investigate the effect...

Toram, Kiran Kumar

2005-11-01

304

Midwest nukes tumble, rock industry: Byron, Marble Hill, Zimmer  

Microsoft Academic Search

The nuclear industry is suffering from a lack of investor confidence because of cancelled projects and the unprecedented rejection of an operating license for Commonwealth Edison's Byron plant on grounds that the utility failed to meet quality assurance responsibilities. When plans to complete the Zimmer and Marble Hill nuclear plants were abandoned, Bechtel came forward with a financing plan that,

Nogee

2009-01-01

305

Energieffektivisering av torktumlare; Improving energy efficiency of a tumble dryer.  

E-print Network

?? Detta examensarbete har utförts i samarbete med Asko Appliances AB i syfte att förbättraenergieffektiviteten hos företagets torktumlare. För att utröna hur parametrarna last, trummansvarvtal… (more)

Johansson, Anton

2010-01-01

306

Biomechanical analysis and control model of hand for object tumbling  

Microsoft Academic Search

In this paper, we propose biomechanical model of the hand control during a manipulation involving contacts with fingers and a support surface. This method allows to quantify the mechanical forces developed by the hand, data difficult to obtain experimentally. An experimental procedure is used to record the kinematics of the hand. The resulting data are exploited by our model to

N. Rezzoug; P. Gorce

1999-01-01

307

NITROGEN MANAGEMENT Rates & Economics  

E-print Network

NITROGEN MANAGEMENT IN 2005 Rates & Economics Larry G. Bundy Dept. of Soil Science University of Wisconsin #12;NITROGEN MANAGEMENT QUESTIONS · Is optimum N rate related to yield? · Is 1.0 to 1.2 lb N recommendations #12;Nitrogen Recommendations for Corn Sands & loamy sand Other soils Yield Potential Organic

Balser, Teri C.

308

Tests of Rating Models  

ERIC Educational Resources Information Center

The study reports empirical tests of Anderson's, Haubensak's, Helson's, and Parducci's rating models when two end anchors are used for rating. The results show that these models cannot predict the judgment effect called here the Dai Pra effect. It is shown that an extension of Anderson's model is consistent with this effect. The results confirm…

Masin, Sergio Cesare; Busetto, Martina

2010-01-01

309

Controlled Rate Cooling  

Technology Transfer Automated Retrieval System (TEKTRAN)

Controlled-rate cooling is one of several techniques available for the long-term storage of plants in liquid nitrogen. In this technique samples are slowly cooled to an intermediate temperature and then plunged in liquid nitrogen. Controlled rate cooling is based on osmotic regulation of cell conte...

310

Mortality Rate, Under-5  

NSDL National Science Digital Library

Under five mortality data for nearly all countries in the world from 2005-2008. A broader measure of child health than infant mortality, this is the probability of dying before ones fifth birthday given the current rates. Rates in countries vary widely from the world average of 67-per-1000 which is decreasing.

Bank, World

311

Structured Rating Scales.  

ERIC Educational Resources Information Center

A rating scale can be expressed as a chain of dichotomous items. The relationship between the dichotomies depends on the manner in which the rating scale is presented to the test taker. Three models for ordered scales are discussed. In the success model, which represents growth, the lowest or easiest category is presented first. If the test taker…

Linacre, John Michael

312

Viral Mutation Rates ?  

PubMed Central

Accurate estimates of virus mutation rates are important to understand the evolution of the viruses and to combat them. However, methods of estimation are varied and often complex. Here, we critically review over 40 original studies and establish criteria to facilitate comparative analyses. The mutation rates of 23 viruses are presented as substitutions per nucleotide per cell infection (s/n/c) and corrected for selection bias where necessary, using a new statistical method. The resulting rates range from 10?8 to10?6 s/n/c for DNA viruses and from 10?6 to 10?4 s/n/c for RNA viruses. Similar to what has been shown previously for DNA viruses, there appears to be a negative correlation between mutation rate and genome size among RNA viruses, but this result requires further experimental testing. Contrary to some suggestions, the mutation rate of retroviruses is not lower than that of other RNA viruses. We also show that nucleotide substitutions are on average four times more common than insertions/deletions (indels). Finally, we provide estimates of the mutation rate per nucleotide per strand copying, which tends to be lower than that per cell infection because some viruses undergo several rounds of copying per cell, particularly double-stranded DNA viruses. A regularly updated virus mutation rate data set will be available at www.uv.es/rsanjuan/virmut. PMID:20660197

Sanjuán, Rafael; Nebot, Miguel R.; Chirico, Nicola; Mansky, Louis M.; Belshaw, Robert

2010-01-01

313

Rating the Risks.  

ERIC Educational Resources Information Center

Explains how people arrive at personal hazard assessments. Explores why people overestimate some hazards and underestimate others. Examines risk ratings for activities and technologies such as nuclear power, motor vehicles, pesticides, and vaccinations. (MA)

Slovic, Paul; And Others

1979-01-01

314

EDP Rates Student Progress  

ERIC Educational Resources Information Center

Article describes the computer-based project in Barstow, California. The project seeks determination of students' learning achievements and whether these learning levels are rising at an acceptable rate to meet predetermined goals. (HB)

Government Data Systems, 1973

1973-01-01

315

Rate Tornado Damage  

NSDL National Science Digital Library

An interactive Flash animation that educates students about the Fujita scale for rating tornado wind speeds and the damage caused by tornados. After being presented with photographs of tornado damage, students are challenged to assign the tornado a rating on the F-scale. The interactive explains the different levels of the F-scale and provides instant feedback on whether or not the correct category was assigned to the tornado.

Lexi Krock

316

Heart Rate Monitors  

NASA Technical Reports Server (NTRS)

Under a NASA grant, Dr. Robert M. Davis and Dr. William M. Portnoy came up with a new type of electrocardiographic electrode that would enable long term use on astronauts. Their invention was an insulated capacitive electrode constructed of a thin dielectric film. NASA subsequently licensed the electrode technology to Richard Charnitski, inventor of the VersaClimber, who founded Heart Rate, Inc., to further develop and manufacture personal heart monitors and to produce exercise machines using the technology for the physical fitness, medical and home markets. Same technology is on both the Home and Institutional Model VersaClimbers. On the Home Model an infrared heart beat transmitter is worn under exercise clothing. Transmitted heart rate is used to control the work intensity on the VersaClimber using the heart rate as the speedometer of the exercise. This offers advantages to a full range of users from the cardiac rehab patient to the high level physical conditioning of elite athletes. The company manufactures and markets five models of the 1*2*3 HEART RATE monitors that are used wherever people exercise to accurately monitor their heart rate. Company is developing a talking heart rate monitor that works with portable headset radios. A version of the heart beat transmitter will be available to the manufacturers of other aerobic exercise machines.

1990-01-01

317

Hydration rate of obsidian.  

PubMed

The hydration rates of 12 obsidian samples of different chemical compositions were measured at temperatures from 95 degrees to 245 degrees C. An expression relating hydration rate to temperature was derived for each sample. The SiO(2) content and refractive index are related to the hydration rate, as are the CaO, MgO, and original water contents. With this information it is possible to calculate the hydration rate of a sample from its silica content, refractive index, or chemical index and a knowledge of the effective temperature at which the hydration occurred. The effective hydration temperature can be either measured or approximated from weather records. Rates have been calculated by both methods, and the results show that weather records can give a good approximation to the true EHT, particularly in tropical and subtropical climates. If one determines the EHT by any of the methods suggested, and also measures or knows the rate of hydration of the particular obsidian used, it should be possible to carry out absolute dating to +/- 10 percent of the true age over periods as short as several years and as long as millions of years. PMID:17782901

Friedman, I; Long, W

1976-01-30

318

Strain-rate effects for high-strain-rate computations  

Microsoft Academic Search

This paper examines the effect of strain rates for computations involving high strain-rates, beyond 103 s - 1. Although it is generally agreed that there is an enhanced rate effect at these higher rates, there is uncertainty regarding the interpretation of dynamic test data, the form of the high-rate effect, and the effect of the high rates on practical problems

G. R. Johnson; T. J. Holmquist; C. E. Anderson Jr.; A. E. Nicholls

2006-01-01

319

Interest rates factor model  

NASA Astrophysics Data System (ADS)

Interdependence of the interest rates of the US, the UK, and Japan is analyzed in this work by means of spectral analysis and network methods. A predominant effective factor in the interest rate market is which country floats a bond issue, and a minor effective factor is time to maturity of bonds. Power-law cross-correlation among different countries is analyzed by the detrended cross-correlation analysis method. Long-range cross-correlation is found between the first factors of interest rate, while there is no cross-correlation between some of the second factors. The tail dependency is indicated by tail indices from Archimedean copulas, including an empirical copula. In contrast to other pairs, the US-UK first factor pair has tail dependencies in both the upper-tail and lower-tail. Dynamic properties of interest rate are modeled by a stochastic volatility model. The properties of mean reverting and volatility clustering are observed and reflected in this model. The proposed simulation method combines the dependence structures and the factor dynamics model; it simultaneously describes the interest rates of different countries.

Lee, Sangwook; Kim, Min Jae; Kim, Soo Yong

2011-07-01

320

ResellerRatings.Com  

NSDL National Science Digital Library

You need a new monitor for your home computer and a company has one for sale really cheap on the 'Net, but you've never heard of them and their Website doesn't exactly inspire confidence. How do you know if they'll give you the deal of a lifetime or just take your money and run? Or (more likely) what if the new monitor does show up but doesn't work? Will you be able to get your money back? It's hard to make a big purchase with doubts like these hanging over your head, but fortunately help is available. As their name implies, ResellerRatings.Com provides ratings of over 1,300 online computer hardware vendors, determined by feedback from people who have purchased products from those vendors. In addition to an overall score, each company's rating is broken down into component totals that evaluate things like how knowledgeable or helpful their salespeople were, whether there were any problems with shipping or delivery, or how well the company dealt with returning or replacing a product. Also available are comments on each company from the customers who contributed to the ratings, so you can get more of a feel for exactly why the scores might be low or high in a given area and, in general, what kind of experience you might have when making your purchase. Overall, ResellerRatings.Com is an invaluable resource for anyone buying computer hardware over the Internet.

321

Federal Reserve Rate Cuts  

NSDL National Science Digital Library

This week's In the News chronicles recent Federal Reserve Board decisions to lower interest rates. The eleven resources discussed provide news, opinion, and consumer information on the FRB BOG action. Following the first US interest rate cut in three years on September 29, 1998, FED Chairman Alan Greenspan caught fire from Wall Street. "Traders were disappointed" in the mere quarter point drop, according to Time business reporter Bernard Baumohl, but "Greenspan will have to make do with the gratitude of the rest of the world." Although the DOW initially fell 54 points Tuesday, a second 0.25% cut to short-term interest rates on October 15, 1998 sent stocks soaring 330 points--the third largest one-day point gain in history. Analysts now hope that US investor optimism--coupled with IMF and World Bank action in Brazil, Russia, and Asia--will ease the world-wide economic crises.

Waters, Megan.

1998-01-01

322

Optical rate sensor algorithms  

NASA Technical Reports Server (NTRS)

Optical sensors, in particular Charge Coupled Device (CCD) arrays, will be used on Space Station to track stars in order to provide inertial attitude reference. Algorithms are presented to derive attitude rate from the optical sensors. The first algorithm is a recursive differentiator. A variance reduction factor (VRF) of 0.0228 was achieved with a rise time of 10 samples. A VRF of 0.2522 gives a rise time of 4 samples. The second algorithm is based on the direct manipulation of the pixel intensity outputs of the sensor. In 1-dimensional simulations, the derived rate was with 0.07 percent of the actual rate in the presence of additive Gaussian noise with a signal to noise ratio of 60 dB.

Uhde-Lacovara, Jo A.

1989-01-01

323

Faucet Flow Rate  

NSDL National Science Digital Library

Students conduct experiments to determine the flow rate of faucets by timing how long it takes to fill gallon jugs. They do this for three different faucet flow levels (quarter blast, half blast, full blast), averaging three trials for each level. They convert their results from gallons per second (gps) to cubic feet per second (cfs).

Civil And Environmental Engineering Department

324

Paradoxes in Film Ratings  

ERIC Educational Resources Information Center

The author selected a simple random sample of 100 movies from the "Movie and Video Guide" (1996), by Leonard Maltin. The author's intent was to obtain some basic information on the population of roughly 19,000 movies through a small sample. The "Movie and Video Guide" by Leonard Maltin is an annual ratings guide to movies. While not all films ever…

Moore, Thomas L.

2006-01-01

325

Average Rate of Change  

NSDL National Science Digital Library

This demo provides students with a concrete understanding of the average rate of change for physical situations and for functions described in tabular or graphic form. Animations in gif and Quicktime format are available, as well as Excel programs for classroom or student use.

Roberts, Lila F.

2005-04-21

326

Recombination Rates in  

Microsoft Academic Search

Recombination occurs during meiosis to produce new allelic combinations in natural populations, making it important for studying evolution. The model system Drosophila has been crucial for understanding the mechanics underlying recombination and assessing the association between recombination rate and several evolutionary parameters. Drosophila was the first system in which genetic maps were developed using recombination frequencies between genes. Linkage maps

Mohamed A F Noor

327

Estimating Rates of Photosynthesis  

NSDL National Science Digital Library

In this lab activity from the Biotechnology Alliance for Suncoast Biology Educators, students will explore photosynthesis, develop a testable hypothesis about the effect of light quality (color) on the rate of photosynthesis of Elodea, and graph measurement data from their testing. The lesson includes background information on photosynthesis, the materials needed, and the procedure.

Keirle, Matt

2012-06-28

328

Currency Exchange Rates.  

ERIC Educational Resources Information Center

This curriculum unit of the Muncie (Indiana) Southside High School is to simulate the dynamics of foreign currency exchange rates from the perspectives of: (1) a major U.S. corporation, ABB Power T & D Company, Inc., of Muncie, Indiana, a manufacturer of large power transformers for the domestic and foreign markets; and (2) individual consumers…

Siler, Carl R.

329

Method and associated apparatus for capturing, servicing and de-orbiting earth satellites using robotics  

NASA Technical Reports Server (NTRS)

This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

2008-01-01

330

Method and associated apparatus for capturing, servicing and de-orbiting earth satellites using robotics  

NASA Technical Reports Server (NTRS)

This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

2007-01-01

331

Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics  

NASA Technical Reports Server (NTRS)

This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

2009-01-01

332

Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics  

NASA Technical Reports Server (NTRS)

This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

2007-01-01

333

Rate Tornado Damage  

NSDL National Science Digital Library

Tornadoes can produce damage that ranges from broken tree limbs to a block of houses swept from their foundations. They can inflict utter devastation across a wide swath of land or, destroy one house and leave others on either side largely untouched. In this interactive feature from NOVA Online, sudents examine a series of photos of tornado damage and assign intensity ratings (on the Fulita scale) based on what they see.

2011-02-24

334

Rotational rate sensor  

DOEpatents

A rate sensor for angular/rotational acceleration includes a housing defining a fluid cavity essentially completely filled with an electrolyte fluid. Within the housing, such as a toroid, ions in the fluid are swept during movement from an excitation electrode toward one of two output electrodes to provide a signal for directional rotation. One or more ground electrodes within the housing serve to neutralize ions, thus preventing any effect at the other output electrode.

Hunter, Steven L. (Livermore, CA)

2002-01-01

335

Rates of Chemical Weathering  

NSDL National Science Digital Library

In this activity, students will investigate the weathering of rocks by chemical processes. They will use effervescent cleansing tablets as a model for rock, and vary surface area, temperature, and acidity to see how rapidly the "rock" dissolves. This investigation will help them understand three of the factors that affect the rate of chemical weathering and develop better understanding of how to design controlled experiments by exploring only one experimental variable at a time.

Passow, Michael

336

Rate Tornado Damage  

NSDL National Science Digital Library

Tornadoes can produce damage that ranges from broken tree limbs to a block of houses swept from their foundations. They can inflict utter devastation across a wide swath of land or, destroy one house and leave others on either side largely untouched. In this interactive feature from NOVA Online, sudents examine a series of photos of tornado damage and assign intensity ratings (on the Fulita scale) based on what they see.

337

Heart Rate and Function  

NSDL National Science Digital Library

The purpose of this activity is to discover and learn about heart rate and the function of the heart. The students will investigate whether their hearts beat slower/faster at different times; develop an understanding of why their hearts beat slower/faster at different times; use data to develop an explanation of why their hearts beat slower/faster at different times; be aware of the effect of exercise on respiration; and be able to describe the major function of the heart.

Mr. Mike Peterson (Frazer Public School)

1999-07-01

338

Behaviorally Anchored Rating Scales vs. Summated Rating Scales: Psychometric Properties and Susceptibility to Rating Bias.  

ERIC Educational Resources Information Center

Using both the Behaviorally Anchored Rating Scales (BARS) and the Purdue University Scales, 727 undergraduates rated 32 instructors. The BARS had less halo effect, more leniency error, and lower interrater reliability. Both formats were valid. The two tests did not differ in rate discrimination or susceptibility to rating bias. (Author/GDC)

Kinicki, Angelo J.; And Others

1985-01-01

339

Rates of Earth degassing  

NASA Technical Reports Server (NTRS)

The degassing of the Earth during accretion is constrained by Pu-U-I-Xe systematics. Degassing was much more efficient during the first 100-200 Ma than subsequently, and it was more complete for Xe than for the lighter gases. More than 90 percent of the degassed Xe escaped from the atmosphere during this period. The combination of fractional degassing of melts and rare gas escape from the atmosphere is able to explain the deficit of terrestrial Xe as a simple consequence of this early degassing history. By the time Xe was quantitatively retained in the atmosphere, the abundances of Kr and the lighter gases in the Earth's interior were similar to or higher than the present-day atmospheric abundances. Subsequent transfer of these lighter rare gases into the atmosphere requires a high rate of post-accretion degassing and melt production. Considerations of Pu-U-Xe systematics suggest that relatively rapid post-accretion degassing was continued to ca. 4.1-4.2 Ga. The present-day degassing history of the Earth is investigated through consideration of rare gas isotope abundances. Although the Earth is a highly degassed body, depleted in rare gases by many orders of magnitude relative to their solar abundances, it is at the present-day losing primordial rare gases which were trapped at the time of accretion.

Onions, R. K.

1994-01-01

340

Propandiol vapor nucleation rates  

NASA Astrophysics Data System (ADS)

Consideration of vapor-gas nucleation as binary vapor nucleation (instead widely used the one component approximation for nucleation of this system now) may lead the progress in the development of nucleation theory. Observations of phase transitions initiated by the carrier gas in the critical embryos of condensate can be a sufficiently convincing argument in this discussion. In order to confirm the role of the carrier gases received in the recent research1, in present study 1,2-propanediol and 1,3-propanediol vapor nucleation rates were measured. Carbon dioxide (Tc=304.2 K,Pc=7.39 MPa) and sulfur hexafluoride (Tc=318.7 K,Pc=3.75 MPa) were chosen as the carrier gases, because of their low and convenient critical temperatures, Tc, and critical pressures, Pc. Analysis of the experimental data shows that gas-carrier molecules are involved in new phase embryo formation. Vapor nucleation of investigated substances in a carrier gas atmosphere can be considered as nucleation of binary system.

Anisimov, M. P.; Nasibulin, A. G.; Timoshina, L. V.; Koropchak, J. A.

2000-08-01

341

High accuracy optical rate sensor  

NASA Technical Reports Server (NTRS)

Optical rate sensors, in particular CCD arrays, will be used on Space Station Freedom to track stars in order to provide inertial attitude reference. An algorithm to provide attitude rate information by directly manipulating the sensor pixel intensity output is presented. The star image produced by a sensor in the laboratory is modeled. Simulated, moving star images are generated, and the algorithm is applied to this data for a star moving at a constant rate. The algorithm produces accurate derived rate of the above data. A step rate change requires two frames for the output of the algorithm to accurately reflect the new rate. When zero mean Gaussian noise with a standard deviation of 5 is added to the simulated data of a star image moving at a constant rate, the algorithm derives the rate with an error of 1.9 percent at a rate of 1.28 pixels per frame.

Uhde-Lacovara, J.

1990-01-01

342

Interviewer's ratings of personality: can these ratings predict job performance?  

E-print Network

INTERVIEWER'S RATINGS OF PERSONALITY: CAN THESE RATINGS PREDICT JOB PERFORMANCE? A Thesis by KATHRYN DIANE ARCHULETA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1998 Major Subject: Psychology INTERVIEWER'S RATINGS OF PERSONALITY: CAN THESE RATINGS PREDICT JOB PERFORMANCES A Thesis by KATHRYN DIANE ARCHULETA Submitted to Texas AtltM University in partial fulfillment...

Archuleta, Kathryn Diane

2012-06-07

343

Interest Rate Transmission to Commercial Credit Rates in Austria  

Microsoft Academic Search

The transmission process from policy-controlled interest rates to bank lending rates deserves reconsideration owing to the implementation of the European Monetary Union (EMU) in 1999. Additional attention to the subject in Austria is due to several large banks which, in 2002, have been charged for not passing on interest rate decreases to their customers. I examine dynamic responses of commercial

Johann Burgstaller; Johannes Kepler

2003-01-01

344

Slip Rates on young faults  

NSDL National Science Digital Library

Students use measured ages and offset of quaternary surfaces to determine vertical slip rates of a young fault. Students then must determine if vertical slip rates have varied significantly through time.

Huerta, Audrey

345

Blood Pressure vs. Heart Rate  

MedlinePLUS

Blood Pressure vs. Heart Rate Updated:Sep 4,2014 Blood pressure and heart rate are not the same. Learn ... last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

346

2007 Wholesale Power Rate Schedules : 2007 General Rate Schedule Provisions.  

SciTech Connect

This schedule is available for the contract purchase of Firm Power to be used within the Pacific Northwest (PNW). Priority Firm (PF) Power may be purchased by public bodies, cooperatives, and Federal agencies for resale to ultimate consumers, for direct consumption, and for Construction, Test and Start-Up, and Station Service. Rates in this schedule are in effect beginning October 1, 2006, and apply to purchases under requirements Firm Power sales contracts for a three-year period. The Slice Product is only available for public bodies and cooperatives who have signed Slice contracts for the FY 2002-2011 period. Utilities participating in the Residential Exchange Program (REP) under Section 5(c) of the Northwest Power Act may purchase Priority Firm Power pursuant to the Residential Exchange Program. Rates under contracts that contain charges that escalate based on BPA's Priority Firm Power rates shall be based on the three-year rates listed in this rate schedule in addition to applicable transmission charges. This rate schedule supersedes the PF-02 rate schedule, which went into effect October 1, 2001. Sales under the PF-07 rate schedule are subject to BPA's 2007 General Rate Schedule Provisions (2007 GRSPs). Products available under this rate schedule are defined in the 2007 GRSPs. For sales under this rate schedule, bills shall be rendered and payments due pursuant to BPA's 2007 GRSPs and billing process.

United States. Bonneville Power Administration.

2006-11-01

347

Optical phase measuring sensors for automated rendezvous and capture  

NASA Technical Reports Server (NTRS)

A technique is described for sensing relative spatial orientations of approach and target vehicles, using optical phase mensuration (in the interferometric sense, as opposed to LIDAR), in place of the more conventional intensity, image, or transit time measurements. This approach permits the parameters to be measured with great accuracy with relatively simple, small sensors having no moving components. A suite of sensors operating on this principle can produce all desired data using either active detection on the target or passive retroreflection to the detectors on the approach vehicle. These optical phase measurements can be applied to determine bearing angle (location of the target vehicle in the approach vehicle coordinates), range, and attitude (orientation of the target vehicle with respect to the line-of-sight). The first two quantities require the approach vehicle to project a modulated interference pattern into space. The bearing angle is determined for a selected point on the target by measuring the phase of the interference pattern at that point using either a detector on the target or a retroreflector on the target and a detector at the transmitter. The range is found by measuring differential bearing angles to predetermined relative instrumentation sites. Two interferometers, a coarse and a fine ranger are required to resolve the 2pi ambiguity.

Metheny, Wayne; Malin, Mark

1991-01-01

348

Frozen-anomaly transformation for the elliptic rendezvous problem  

NASA Astrophysics Data System (ADS)

A new solution to relative motion on elliptical orbits is presented, based on a novel transformation from the reference state vector to the relative state vector. The relative orbit is constructed assuming that the anomaly, and not the time, is the invariant element throughout the transformation. This concept arises naturally from the variational form of anomaly-explicit formulations. In particular, this paper explores the capabilities of a formulation developed by Peláez et al. (Celest Mech Dyn Astron. 97, 131-150, 2007), called Dromo. This formulation exploits the advantages of the ideal reference frames and quaternionic descriptions of the orbital plane. The linear variational form of the equations of motion in Dromo is developed herein, and the resulting transformation matrix is presented. When applied to the reference state vector, this linear transformation provides the relative state vector at any step. The invariance in the anomaly implies a certain time delay in the results. Physical times for leader and follower do not coincide after the transformation. To recover the sense of the solution an additional correction is applied a posteriori to cancel this intrinsic time delay. The performance of the new transformation is compared against previous solutions to the problem through a set of numerical examples. Important error reductions in determining the relative orbit are observed in these tests.

Roa, Javier; Peláez, Jesús

2015-01-01

349

Gemini - John W. Young in Rendezvous Docking Simulator  

NASA Technical Reports Server (NTRS)

Astronaut John Young (above) was one of 14 astronauts, 8 NASA test pilots, and 2 McDonnell test pilots who took part in simulator studies. Young piloted the simulator on November 12, 1963 Arthur Vogeley wrote: 'Many of the astronauts have flown this simulator in support of the Gemini studies and they, without exception, appreciated the realism of the visual scene. The simulator has also been used in the development of pilot techniques to handle certain jet malfunctions in order that aborts could be avoided. In these situations large attitude changes are sometimes necessary and the false motion cues that were generated due to earth gravity were somewhat objectionable; however, the pilots were readily able to overlook these false motion cues in favor of the visual realism.' Roy F. Brissenden wrote:'The basic Gemini control studies developed the necessary techniques and demonstrated the ability of human pilots to perform final space docking with the specified Gemini-Agena systems using only visual references. ... Results... showed that trained astronauts can effect the docking with direct acceleration control and even with jet malfunctions as long as good visual conditions exist.... Probably more important than data results was the early confidence that the astronauts themselves gained in their ability to perform the maneuver in the ultimate flight mission.'

1963-01-01

350

Orbital rendezvous using an Augmented Lambert Guidance scheme  

E-print Network

The development of an Augmented Lambert Guidance Algorithm that matches the position and velocity of an orbiting target spacecraft is presented in this thesis. The Augmented Lambert Guidance Algorithm manipulates the inputs ...

MacLellan, Sara Jean

2005-01-01

351

Rendezvous with the World: Missouri Southern State University's Themed Semesters  

ERIC Educational Resources Information Center

Although most universities emphasize study abroad as the primary vehicle to internationalize the campus, in reality only a small percentage of students actually participate in this endeavor. The internationally themed semesters at Missouri Southern State University (MSSU) reach virtually every student, and provide a global perspective and cultural…

Stebbins, Chad

2011-01-01

352

Challenges to situated morality: Maintaining respectability in a sexual rendezvous  

Microsoft Academic Search

A clandestine motel operation is described, concentrating upon the staff and patrons as they attempt to maintain respectability within a context of situated morality that is shifting, challenging previously negotiated realities. The staff members tend toward a refulgent respectability, using vocabularies of denial to maintain respectability. Patrons, categorized as regular customers, special customers, careful people and problem people, may seek

J. Robert Lilly; Richard A. Ball

1980-01-01

353

Orbital Express AVGS Validation and Calibration for Automated Rendezvous  

NASA Technical Reports Server (NTRS)

From March to July of 2007, the DARPA Orbital Express mission achieved a number of firsts in autonomous spacecraft operations. The NASA Advanced Video Guidance Sensor (AVGS) was the primary docking sensor during the first two dockings and was used in a blended mode three other automated captures. The AVGS performance exceeded its specification by approximately an order of magnitude. One reason that the AVGS functioned so well during the mission was that the validation and calibration of the sensor prior to the mission advanced the state-of-the-art for proximity sensors. Some factors in this success were improvements in ground test equipment and truth data, the capability for ILOAD corrections for optical and other effects, and the development of a bias correction procedure. Several valuable lessons learned have applications to future proximity sensors.

Heaton, Andrew F.; Howard, Richard T.; Pinson, Robin M.

2008-01-01

354

A Deterministic Multi-Way Rendezvous Library for Haskell  

E-print Network

)) -- thread writes 4 to m a parent thread reads m b parent thread reads m putStrLn (show a) Output: 3 or 4 #12;Our Approach Uses the SHIM model: · Parent thread waits for children to finish · Threads run asynchronously but synchronize (communicate) when data has to be shared

355

Rendezvous with History: Franklin and Eleanor Roosevelt State Historical Site  

NSDL National Science Digital Library

Among the many family homes that have served as places of tranquility for U.S. presidents, the grounds and buildings of Hyde Park, New York loom large within the life experiences of the Roosevelt family. This site, provided by the Poughkeepsie Journal, offers a virtual tour of the Franklin D. Roosevelt Historic Site, complete with 360 degree views, essays, and a timeline of important events related to the family estate. Visitors will want to begin by perusing the fine interactive map of the grounds, as they can take an inside look at such buildings as the Presidential Library, the Henry A. Wallace Visitor Center, and the historic home of Franklin and Eleanor Roosevelt, Springwood. The stories section really brings out the spirit of both FDR and Eleanor, as they talk about their lives and legacies, along with providing transcripts of some of FDRâÂÂs most well-known speeches, such as the Four Freedoms delivery and the declaration of war against Japan. Finally, visitors will want to also take a look through some of the 360-degree views offered here, including a tour of the famed room where the Fireside Chats were delivered and FDRâÂÂs bedroom.

356

Rendezvous-Based Directional Routing: A Performance Analysis  

E-print Network

. [26] proposed several ways to mitigate these issues by tessellating low cost FSO transceivers in a spherical fashion (see Figure 1) and replacing long-haul point-to-point links with short, multi to provide over 98% connectivity while maintaining only O(N3/2 ) evenly distributed states at a cost of only

Kalyanaraman, Shivkumar

357

ANNUAL ADULT SURVIVAL RATES OF  

Microsoft Academic Search

The purposes of this study were (1) to determine annual adult survival rates from banding data for each sex of the Brown-headed Cowbird (Molothrus ater), Common Grackle (Quiscalus quiscula), Red-winged Blackbird (Agelaius phoeniceus), and Starling (Sturnus vulgaris), and (2) to compare survival rates calculated from band returns with survival rates calculated from band recoveries. Others have studied annual adult survival

DON P. FANKHAIJSER

358

Rate of Reading and Auding.  

ERIC Educational Resources Information Center

A review of literature related to rate of reading and auding, primarily in non-remedial high school and adult readers, is provided in this paper. After offering a definition of reading, a discussion of those studies which examine rates of reading and auding separately is provided with a summary of studies which directly relate rates of reading and…

Fulmer, Robert

359

Stocking Rates for Horse Pastures  

Technology Transfer Automated Retrieval System (TEKTRAN)

Decision on which stocking rate to graze a horse pasture is critical, particularly if the forage is expected to meet the nutrient needs of the horses. Challenges and management for targeting the optimum stocking rate, defined as the stocking rate that allows forage consumption to approximately equ...

360

Mirage of Floating Exchange Rates  

Microsoft Academic Search

This note summarizes some of the highlights of my longer paper with Guillermo Calvo”Fear of Floating.” Many emerging market countries have suffered financial crises. One view blames soft pegs for these crises. Adherents to that view suggest that countries move to corner solutions--hard pegs or floating exchange rates. We analyze the behavior of exchange rates, reserves, and interest rates to

Carmen M. Reinhart

2000-01-01

361

AGRICULTURAL EXCHANGE RATE DATA SHEET  

EPA Science Inventory

The ERS data set contains annual and monthly data for exchange rates important to U.S. agriculture. It includes both nominal and real exchange rates for 80 countries (plus the European Union) as well as real trade-weighted exchange rate indexes for many commodities and aggregatio...

362

Asymptotic Cellular Growth Rate as the Effective Information Utilization Rate  

E-print Network

We study the average asymptotic growth rate of cells in randomly fluctuating environments. Using a game-theoretic perspective, we show that any response strategy has an asymptotic growth rate, which is the sum of: (i) the maximal growth rate at the worst possible distribution of environments, (ii) relative information between the actual distribution of environments to the worst one, and (iii) information utilization rate which is the information rate of the sensory devices minus the "information dissipation rate", the amount of information not utilized by the cell for growth. In non-stationary environments, the optimal strategy is the time average of the instantaneous optimal strategy and the optimal switching times are evenly spaced in the statistical (Fisher) metric.

Pugatch, Rami; Tlusty, Tsvi

2013-01-01

363

Saturn component failure rate and failure rate modifiers  

NASA Technical Reports Server (NTRS)

Failure mode frequency ratios, environmental adjustment factors, and failure rates for mechanical and electromechanical component families are presented. The failure rates and failure rate modifiers resulted from a series of studies whose purpose was to provide design, tests, reliability, and systems engineers with accurate, up-to-date failure rate information. The results of the studies were achieved through an extensive engineering analysis of the Saturn Program test data and Unsatisfactory Condition Reports (UCR's) and the application of mathematical techniques developed for the studies.

1971-01-01

364

A new silicon rate gyroscope  

Microsoft Academic Search

HSG-IMIT is developing a new silicon rate gyroscope of very small size, low cost, and high performance. The device is called MARS-RR, which means micromachined angular rate sensor with two rotary oscillation modes. First prototypes, MARS-RRI yielded random walk and bias stability as low as 0.27 deg\\/?h and 65 deg\\/h, respectively. The noise equivalent rate (3 ?) corresponds to a

W. Geiger; B. Folkmer; J. Merz; H. Sandmaier; W. Lang

1998-01-01

365

Failure rates of contraceptive methods.  

PubMed

A discussion of the measures used to determine the failure rates of contraceptive methods precedes the presentation of a table that presents the theoretical and use failure rates for the following contraceptive methods: condom; coitus interruptus; diaphragm; IUD; oral contraceptive combined; oral contraceptive, progestogen only; vasectomy; tubal ligation; spermicidal foam; depo-provera; chance; lactation for 12 months; and the symptothermal method of natural family planning. A commonly used measure of contraceptive effectiveness is the Pearl Index. It measures the percentage of sexually active women who become pregnant while using a method for 1 year and can be expressed as either the minimum failure rate (theoretical failure rate) or as a maximum failure rate (use failure rate). Whether an individual or a couple operates at the minimum or maximum failure rate or somewhere in-between is dependent on: the basic contraceptive priorities of the method; the information provided by the practitioner for its use; and the extent of the user's compliance with the instructions. Theoretical failure rate is defined as the method's failure rate when the user receives correct instructions and follows these instructions conscientiously. The use failure rate is defined as the method's failure rate in actual use which includes: the user receiving incorrect instructions as to method use; the user forgetting to use the method sometimes or not using the method correctly. Theoretical failure rates listed in the table are: condom, 0.4-1.6; diaphragm, 2; IUD, 1-3; combined OC, 0.1; progestogen only OC, 1-2; vasectomy 0.1; tubal ligation 0.04; spermicidal foam, 3; depo-provera, 1; lactation for 12 months, 25; coitus interruptus, 9; and the symptothermal method -- variant A, 1.5; variant B, 3.39; and variant C, 11.2. PMID:12263458

Mclure, Z

1981-04-01

366

Staff Survey: response rate Department Returns Headcount Rate  

E-print Network

Staff Survey: response rate Department Returns Headcount Rate ACADEMIC UNIT OF MEDICAL EDUCATION 34% AMRC 55 175 31% ANIMAL & PLANT SCIENCES 57 138 41% ARCHAEOLOGY 34 51 67% ARCHITECTURE 33 59 56 & BIOTECHNOLOGY 51 111 46% MUSIC 18 21 86% NEUROSCIENCE 25 79 32% NURSING & MIDWIFERY 28 36 78% ONCOLOGY 85 196 43

Li, Yi

367

Nontraditional Student Graduation Rate Benchmarks  

ERIC Educational Resources Information Center

The prominence of discourse on postsecondary degree completion, student persistence, and retention has increased in the national dialogue. Heightened attention to college completion rates by the federal government and pressure to tie state funding to performance metrics associated with graduation rates are catalysts for the discussion.…

Miller, Nathan B.

2014-01-01

368

Graduation Rates Fall for Athletes.  

ERIC Educational Resources Information Center

Graduation rates of National Collegiate Athletic Association (NCAA) Division I scholarship athletes have shown the first across-the-board decline since the Association began publishing rates in 1990. Much attention this year has focused on male basketball players; only 41% of those who entered college in 1991 graduated within six years. Many leave…

Haworth, Karla

1998-01-01

369

Exchange Rates and Financial Fragility  

Microsoft Academic Search

In this paper we analyze three views of the relationship between the exchange rate and financial fragility: (1) the moral hazard hypothesis, according to which pegged exchange rates offer implicit insurance against exchange risk and thereby encourage reckless borrowing and lending; (2) the original sin hypothesis, which emphasizes an incompleteness in financial markets which prevents the domestic currency from being

Barry Eichengreen; Ricardo Hausmann

1999-01-01

370

Swap Rates and Credit Quality  

Microsoft Academic Search

This article presents a model for valuing claims subject to default by both contracting parties, such as swaps and forwards. With counterparties of different default risk, the promised cash flows of a swap are discounted by a switching discount rate that, at any given state and time, is equal to the discount rate of the counterparty for whom the swap

Darrell Duffie; Ming Huang

1996-01-01

371

Supergranule Rotation Rates and Lifetimes  

NASA Technical Reports Server (NTRS)

Previous measurements of the rotation rate of the supergranule Doppler pattern have revealed three interesting characteristics. 1) The supergranule pattern rotates faster than the plasma at the surface and, at each latitude, it rotates faster than the plasma at any level below the surface. 2) Larger cells rotate more rapidly than smaller cells. 3) Faster rotation rates are found when using larger time lags between Doppler images. These last two characteristics are consistent with the idea that large cells live longer and extend deeper into the Sun where the rotation rate is faster. A re-examination of the rotation rates and lifetimes of the Doppler patterns seen with the Michelson Doppler Imager (MDI) instrument on Solar and Heliospheric Observatory (SOHO) confirms these characteristics. However, a simulation of the data using a spectrum for the cellular flows that matches the observed spectrum shows that these characteristics can be largely reproduced by cellular patterns that rotate at the same rate without any dependence upon cell size, The rotation rate , and its dependence on latitude, is nonetheless still faster than the surface or internal rotation rate. The difference in rotation rates as functions of cell size and time lag between observations is attributed to projection effects on the line-of-sight Doppler signal. This data simulation is also used to determine characteristic lifetimes for the cellular patterns as a function of cell size. These lifetime determinations are also affected by projection effects on the line-of-sight Doppler signal.

Hathaway, David H.; Six, N. Frank (Technical Monitor)

2002-01-01

372

4, 120, 2004 Meteor rates  

E-print Network

ACPD 4, 1­20, 2004 Meteor rates W. Singer et al. Title Page Abstract Introduction Conclusions of meteor rates at the Arctic circle W. Singer, J. Wei�, and U. von Zahn Leibniz-Institute of Atmospheric: 6 January 2004 Correspondence to: W. Singer (singer@iap-kborn.de) 1 #12;ACPD 4, 1­20, 2004 Meteor

Paris-Sud XI, Université de

373

Towards Smart Grid Dynamic Ratings  

NASA Astrophysics Data System (ADS)

The energy distribution industry is giving greater attention to smart grid solutions as a means for increasing the capabilities, efficiency and reliability of the electrical power network. The smart grid makes use of intelligent monitoring and control devices throughout the distribution network to report on electrical properties such as voltage, current and power, as well as raising network alarms and events. A further aspect of the smart grid embodies the dynamic rating of electrical assets of the network. This fundamentally involves a rating of the load current capacity of electrical assets including feeders, transformers and switches. The mainstream approach to rate assets is to apply the vendor plate rating, which often under utilizes assets, or in some cases over utilizes when environmental conditions reduce the effective rated capacity, potentially reducing lifetime. Using active intelligence we have developed a rating system that rates assets in real time based upon several events. This allows for a far more efficient and reliable electrical grid that is able to extend further the life and reliability of the electrical network. In this paper we describe our architecture, the observations made during development and live deployment of the solution into operation. We also illustrate how this solution blends with the smart grid by proposing a dynamic rating system for the smart grid.

Cheema, Jamal; Clark, Adrian; Kilimnik, Justin; Pavlovski, Chris; Redman, David; Vu, Maria

2011-08-01

374

Fast Rates for Regularized Objectives  

Microsoft Academic Search

We study convergence properties of empirical minimization of a stochastic strongly convex objective, where the stochastic component is linear. We show that the value attained by the empirical minimizer converges to the optimal value with rate 1=n. The result applies, in particular, to the SVM objective. Thus, we obtain a rate of 1=n on the convergence of the SVM objective

Karthik Sridharan; Shai Shalev-shwartz; Nathan Srebro

2008-01-01

375

Regulation of Human Heart Rate  

NSDL National Science Digital Library

Students learn how to measure heart rate accurately. Then students design and carry out an experiment to test the effects of an activity or stimulus on heart rate, analyze and interpret the data, and present their experiments in a poster session. In this activity students learn about both cardiac physiology and experimental method.

Ingrid Waldron

376

ratings  

Cancer.gov

Informative 36 36 37 37 Interesting 23 30 23 35 Meaningful 23 28 --- --- Relevant 28 29 25 29 Something you could relate to 36 37 37 34 Told you something important 23 25 28 28 Told you something new 30 28 26 27 Worth remembering 22 33 19 --- 1 This table, based on the Ipsos-ASI, Inc., Market Research Database of Diagnostic Norms, includes national averages for standard copy test questions used in testing commercial ads.

377

The Airline Quality Rating 2002  

NASA Technical Reports Server (NTRS)

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, Airline Quality Rating 2002, reflects monthly Airline Quality Rating scores for 2001. AQR scores for the calendar year 2001 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2002 is a summary of month-by-month quality ratings for the 11 largest U.S. airlines operating during 2001. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2001 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2001, and industry average results. Also, comparative Airline Quality Rating data for 2000 are included for each airline to provide historical perspective regarding performance quality in the industry.

Bowen, Brent D.; Headley, Dean E.

2002-01-01

378

The Airline Quality Rating 2003  

NASA Technical Reports Server (NTRS)

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2003, reflects monthly Airline Quality Rating scores for 2002. AQR scores for the calendar year 2002 are based on 15 elements that focus on airline performance areas important to air travel consumers. The Airline Quality Rating 2003 is a summary of month-by-month quality ratings for the 10 largest U.S. airlines operating during 2002. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of ontime arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2002 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2002, and industry average results. Also, comparative Airline Quality Rating data for 2001 are included for each airline to provide historical perspective regarding performance quality in the industry.

Bowen, Brent D.; Headley, Dean E.

2003-01-01

379

The Airline Quality Rating 2004  

NASA Technical Reports Server (NTRS)

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2004, reflects monthly Airline Quality Rating scores for 2003. AQR scores for the calendar year 2003 are based on 15 elements in four major areas that focus on airline performance aspects important to air travel consumers. The Airline Quality Rating 2004 is a summary of month-by-month quality ratings for U.S. airlines that have at least 1 % of domestic passenger volume during 2003. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2003 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2003, and industry results. Also, comparative Airline Quality Rating data for 2002 are included, where available, to provide historical perspective regarding performance quality in the industry.

Fink, Mary M. (Editor); Bowen, Brent D.; Headley, Dean E.

2004-01-01

380

The Airline Quality Rating 2004  

NASA Technical Reports Server (NTRS)

The Airline Quality Rating (AQR) was developed and first announced in early 1991 as an objective method of comparing airline quality on combined multiple performance criteria. This current report, the Airline Quality Rating 2004, reflects monthly Airline Quality Rating scores for 2003. AQR scores far the calendar year 2003 are based on 15 elemnts in four major areas that focus on airline performance aspects important to air travel consumers. The Airline Quality Rating 2004 is a summary of month-by-month quality ratings for U.S. airlines that have at least 1% of domestic passenger volume during 2003. Using the Airline Quality Rating system of weighted averages and monthly performance data in the areas of on-time arrivals, involuntary denied boardings, mishandled baggage, and a combination of 12 customer complaint categories, airlines comparative performance for the calendar year of 2003 is reported. This research monograph contains a brief summary of the AQR methodology, detailed data and charts that track comparative quality for domestic airline operations for the 12-month period of 2003, and industry results. Also, comparative Airline Quality Rating data for 2002 are included, where available, to provide historical perspective

Bowen, Brent D.; Headley, Dean E.

2004-01-01

381

Lung Cancer Rates by State  

MedlinePLUS

... Delaware, Indiana, Kentucky, Louisiana, Maine, Mississippi, Missouri, Oklahoma, Tennessee, and West Virginia Light Gray Data not availableâ?¡ ... Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Ohio, Oklahoma, Tennessee, and West Virginia *Rates are per 100,000 ...

382

Sun-Protective Behavior Rates  

MedlinePLUS

... Ovarian Prostate Uterine Vaginal and Vulvar Cancer Home Sun-Protective Behavior Rates Language: English Español (Spanish) Share ... usually practice at least one of the three sun-protective behaviors (use sunscreen, wear sun-protective clothing, ...

383

Growth rates of protein crystals  

PubMed Central

Protein crystallization is important for structural biology. The rate at which a protein crystallizes is often the bottleneck in determining the protein’s structure. Here, we give a physical model for the growth rates of protein crystals. Most materials crystallize faster under stronger growth conditions, however, protein crystallization slows down under the strongest conditions. Proteins require a crystallization slot of ’just right’ conditions. Our model provides an explanation. Unlike simpler materials, proteins are orientationally asymmetrical. Under strong conditions, protein molecules attempt to crystallize too quickly, in wrong orientations, blocking surface sites for more productive crystal growth. The model explains the observation that increasing the net charge on a protein increases the crystal growth rate. The model predictions are in good agreement with experiments on the growth rates of tetragonal lysozyme crystals as a function of pH, salt concentration, temperature, and protein concentration. PMID:22339624

Schmit, Jeremy D.; Dill, Ken

2012-01-01

384

High repetition rate fiber lasers  

E-print Network

This thesis reports work in high repetition rate femtosecond fiber lasers. Driven by the applications including optical arbitrary waveform generation, high speed optical sampling, frequency metrology, and timing and frequency ...

Chen, Jian, Ph. D. Massachusetts Institute of Technology

2009-01-01

385

Variability of Plasmaspheric Rotation Rate  

NASA Astrophysics Data System (ADS)

The plasmasphere has been observed to rotate at a rate different than that of the Earth itself. Previous studies such as Burch et al. [2003] have linked plasmaspheric sub-corotation to joule heating of the polar ionosphere during periods of high geomagnetic activity, and have supported it with an individual case study observation. We carry out a statistical survey of plasmaspheric rotation rates over several months of IMAGE EUV data in 2001, correlating the results with geomagnetic indices. An automated cross-correlation routine is used to track azimuthal features such as "notches" over a single pass of the IMAGE satellite, providing an estimate of the plasmasphere's rotation rate. Observed trends and possible causes of the variability of rotation rate are discussed.

Galvan, D. A.; Moldwin, M. B.; Sandel, B. R.

2008-05-01

386

78 FR 14821 - Fee Rate  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF THE INTERIOR National Indian Gaming Commission Fee Rate AGENCY: National Indian Gaming Commission, Interior. ACTION: Notice...25 CFR 514.2, that the National Indian Gaming Commission has adopted its 2013...

2013-03-07

387

Strain Rates and Material Spins  

Microsoft Academic Search

The material time rate of Lagrangean strain measures, objective corotational rates of Eulerian strain measures and their defining\\u000a spin tensors are investigated from a general point of view. First, a direct and rigorous method is used to derive a simple\\u000a formula for the gradient of the tensor-valued function defining a general class of strain measures. By means of this formula

Heng Xiao; Otto Timme Bruhns; Albert Thomas Marie Meyers

1998-01-01

388

Strain rate sensitive constitutive equations  

E-print Network

Experiments On Annealed Aluminum 44 Figure 5 Figure 6 liaterial Parameters For Annealed Aluminum, fn(e ? I) = li& (f/c ) + C F n' o St. ress-Strain Behavior In Shear I'or Aluminum 45 1100-0 55 Figure 7 Experimental and Theoreti. cal Rate Sensitivity..., theoreti- cal wave propagation relating to strain rate and experimental in- vestigations. In the theoretical section, discrepancies arise be- tween the mathematical models due to the assumptions used to describe various material's zesponse...

Nelson, Charles Edward

2012-06-07

389

Microfluidic Devices and Flow Rate  

NSDL National Science Digital Library

Students obtain a basic understanding of microfluidic devices, how they are developed and their uses in the medical field. After conducting the associated activity, they watch a video clip and learn about flow rate and how this relates to the speed at which medicine takes effect in the body. What they learn contributes to their ongoing objective to answer the challenge question presented in lesson 1 of this unit. They conclude by solving flow rate problems provided on a worksheet.

VU Bioengineering RET Program,

390

Electric Rate Alternatives to Cogeneration  

E-print Network

, but commercial and residential sales as well. ALTERNATIVES Faced with the downturn in the economy, a general downturn in the sales of electricity and severe financial duress caused by a large construction program. several alternatives appeared possible..."ELECTRIC RATE ALTERNATIVES TO COGENERATION" K. R. SANDBERG, JR. INDUSTRIAL ACCOUNTS MANAGER - TEXAS GULF STATES UTILITIES COMPANY BEAUMONT, TEXAS ABSTRACT This paper discusses electric rate slternatives to cogeneration for the industrisl...

Sandberg, K. R. Jr.

391

Heart rate variability: a review  

Microsoft Academic Search

Heart rate variability (HRV) is a reliable reflection of the many physiological factors modulating the normal rhythm of the\\u000a heart. In fact, they provide a powerful means of observing the interplay between the sympathetic and parasympathetic nervous\\u000a systems. It shows that the structure generating the signal is not only simply linear, but also involves nonlinear contributions.\\u000a Heart rate (HR) is

U. Rajendra Acharya; Paul K. Joseph; N. Kannathal; Choo Min Lim; Jasjit S. Suri

2006-01-01

392

5 CFR 531.245 - Computing locality rates and special rates for GM employees.  

Code of Federal Regulations, 2010 CFR

...Computing locality rates and special rates for GM employees. 531.245 Section 531...Determining Rate of Basic Pay Special Rules for Gm Employees § 531.245 Computing locality rates and special rates for GM employees. Locality rates and...

2010-01-01

393

Rating scales for musician's dystonia  

PubMed Central

Musician's dystonia (MD) is a focal adult-onset dystonia most commonly involving the hand. It has much greater relative prevalence than non-musician’s focal hand dystonias, exhibits task specificity at the level of specific musical passages, and is a particularly difficult form of dystonia to treat. For most MD patients, the diagnosis confirms the end of their music performance careers. Research on treatments and pathophysiology is contingent upon measures of motor function abnormalities. In this review, we comprehensively survey the literature to identify the rating scales used in MD and the distribution of their use. We also summarize the extent to which the scales have been evaluated for their clinical utility, including reliability, validity, sensitivity, specificity to MD, and practicality for a clinical setting. Out of 135 publications, almost half (62) included no quantitative measures of motor function. The remaining 73 studies used a variety of choices from among 10 major rating scales. Most used subjective scales involving either patient or clinician ratings. Only 25% (18) of the studies used objective scales. None of the scales has been completely and rigorously evaluated for clinical utility. Whether studies involved treatments or pathophysiologic assays, there was a heterogeneous choice of rating scales used with no clear standard. As a result, the collective interpretive value of those studies is limited because the results are confounded by measurement effects. We suggest that the development and widespread adoption of a new clinically useful rating scale is critical for accelerating basic and clinical research in MD. PMID:23884039

Berque, Patrice; Jabusch, Hans-Christian; Altenmüller, Eckart; Frucht, Steven J.

2013-01-01

394

The Rate of Turbulent Spherical Accretion  

E-print Network

The rate of turbulent spherical accretion onto a compact object might be much smaller than the Bondi rate. It is suggested that the rate of accretion onto Sgr A-star is much smaller than the Bondi rate.

Andrei Gruzinov

1998-09-21

395

Lung Cancer Rates by Race and Ethnicity  

MedlinePLUS

... and ethnicity. Incidence Rates by Race/Ethnicity and Sex "Incidence rate" means how many people out of ... Alaska Native). Death Rates by Race/Ethnicity and Sex From 1999â??2011, the rate of people dying ...

396

HEART RATE VARIABILITY AND 24-HOUR MINIMUM HEART RATE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Heart rate variability (HRV) indices based on 24-hour electrocardiograph recordings have been used in clinical research studies to assess the aggregate activity of the autonomic nervous system. While 24-hour HRV is generally considered non-invasive, use in research protocols typically involves cons...

397

Dual physiological rate measurement instrument  

NASA Technical Reports Server (NTRS)

The object of the invention is to provide an instrument for converting a physiological pulse rate into a corresponding linear output voltage. The instrument which accurately measures the rate of an unknown rectangular pulse wave over an extended range of values comprises a phase-locked loop including a phase comparator, a filtering network, and a voltage-controlled oscillator, arranged in cascade. The phase comparator has a first input responsive to the pulse wave and a second input responsive to the output signal of the voltage-controlled oscillator. The comparator provides a signal dependent on the difference in phase and frequency between the signals appearing on the first and second inputs. A high-input impedance amplifier accepts an output from the filtering network and provides an amplified output DC signal to a utilization device for providing a measurement of the rate of the pulse wave.

Cooper, Tommy G. (inventor)

1990-01-01

398

Reaction Rates, Catalysis, and Pasteurization  

NSDL National Science Digital Library

In this activity, by the Concord Consortium's Molecular Literacy project, students are introduced to "key ideas of chemistry, including reaction rates, bond strength, activation energy, catalysis, and equilibrium." Upon completion of this activity students should be able to describe and manipulate models to discover how reaction rates, energy, bond strength, catalysis, and equilibrium are related; manipulate reaction rates by changing temperature and concentration; demonstrate their understanding by creating an endothermic reaction that releases a lot of heat energy, one that requires a catalyst, and one that reaches equilibrium between reactants and products. The activity itself is a java-based interactive resource built upon the free, open source Molecular Workbench software. In the activity, students are allowed to explore at their own pace in a digital environment full of demonstrations, illustrations, and models they can manipulate. In addition to the activity, visitors will find an overview of the activity, a test and rubric, central concepts, and their correlation to AAAS standards.

2008-10-23

399

GR Schwarzschild Particle Rate Program  

NSDL National Science Digital Library

The GR Schwarzschild Particle Rate program simulates orbits of objects around a black hole using the Schwarzschild metric. It displays data on the position and local time of the orbiter as well as a plot of the effective potential well in which the orbiting particle resides. The default configuration is a circular orbit. GR Schwarzschild Particle Rate is part of a suite of Open Source Physics programs that model aspects of General Relativity. It is distributed as a ready-to-run (compiled) Java archive.Double clicking the gr_schwarzschild_particle_rate.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or General Relativity.

Christian, Wolfgang; Belloni, Mario; Cox, Anne

2008-05-23

400

High Data Rate Instrument Study  

NASA Technical Reports Server (NTRS)

The High Data Rate Instrument Study was a joint effort between the Jet Propulsion Laboratory (JPL) and the Goddard Space Flight Center (GSFC). The objectives were to assess the characteristics of future high data rate Earth observing science instruments and then to assess the feasibility of developing data processing systems and communications systems required to meet those data rates. Instruments and technology were assessed for technology readiness dates of 2000, 2003, and 2006. The highest data rate instruments are hyperspectral and synthetic aperture radar instruments which are capable of generating 3.2 Gigabits per second (Gbps) and 1.3 Gbps, respectively, with a technology readiness date of 2003. These instruments would require storage of 16.2 Terebits (Tb) of information (RF communications case of two orbits of data) or 40.5 Tb of information (optical communications case of five orbits of data) with a technology readiness date of 2003. Onboard storage capability in 2003 is estimated at 4 Tb; therefore, all the data created cannot be stored without processing or compression. Of the 4 Tb of stored data, RF communications can only send about one third of the data to the ground, while optical communications is estimated at 6.4 Tb across all three technology readiness dates of 2000, 2003, and 2006 which were used in the study. The study includes analysis of the onboard processing and communications technologies at these three dates and potential systems to meet the high data rate requirements. In the 2003 case, 7.8% of the data can be stored and downlinked by RF communications while 10% of the data can be stored and downlinked with optical communications. The study conclusion is that only 1 to 10% of the data generated by high data rate instruments will be sent to the ground from now through 2006 unless revolutionary changes in spacecraft design and operations such as intelligent data extraction are developed.

Schober, Wayne; Lansing, Faiza; Wilson, Keith; Webb, Evan

1999-01-01

401

Surrender Rate Impacts on Asset Liability Management  

Microsoft Academic Search

We try to model surrender rates with a few explanatory variables such as the difference between reference new money rates and product crediting rates with surrender charges, the policy age since the contract was issued, unemployment rates, economy growth rates, and seasonal effects. In modeling surrender rates we use the logit function. We calculate the value of interest indexed annuities

Changki Kim

2005-01-01

402

2013 Advertising Rates Effective January 2013  

E-print Network

2013 Advertising Rates Effective January 2013 Journal Position Specs Issue Space Art Afterall;2013 Advertising Rates Effective January 2013 Journal Position Specs Issue Space Art Rates Deadlines Rate The China Rates Deadlines Rate Please visit www.afterall.org/journal/advertise for advertising opportunities. 3

Scherer, Norbert F.

403

Calculating and Comparing Tax Rates  

NSDL National Science Digital Library

This example focuses on six letters to the editor. All six letters attempt to describe and compare the amount of taxes paid on two different incomes: $30,000 and $200,000. Tax rates are expressed in absolute dollars, tax per $1,000 of income, $1 of tax per income amount, and as percents of annual income. Students need to be able to organize the relevant information and convert each stated tax rate to a standard form to help make comparisons. Additionally, students need to be aware that letter writers may make their own mistakes!

Boersma, Stuart

404

Incentive Rates- At What Cost?  

E-print Network

, either by increasing use of an existing unused asset or in some other way, that should be an overriding consideration. I also believe a rate that economically harms no one but creates an advantage for some customer is worthy of consid eration. Here I... am thinking parochially, limiting my review of harm to my own service area. The concept of harm leads us nicely to our next topic, discrimination. I believe that this is one of the most difficult problems of incen tive rates. There should be a...

Schaeffer, S. C.

405

Precise, Facile Initial Rate Measurements†  

PubMed Central

Progress curve analysis has been used sparingly in studies of enzyme-catalyzed reactions due largely to the complexity of the integrated rate expressions used in data analysis. Using an experimental design that simplifies the analysis, the advantages and limitations of progress curve experiments are explored in a study of four different enzyme-catalyzed reactions. The approach involves relatively simple protocols, requires 20–25% of the materials, and provides 10- to 20-fold signal enhancements compared to analogous initial rate studies. Product inhibition, which complicates integrated rate analysis, was circumvented using cloned, purified enzymes that remove the products and draw the reaction forward. The resulting progress curves can be transformed into the equivalent of thousands of initial rate and [S] measurements and, due to the absence of product inhibition, are plotted in the familiar, linear double-reciprocal format. Allowing product to accumulate during a reaction produces a continuously changing substrate/product ratio that can be used as the basis for obtaining product inhibition constants and to distinguish among the three classical inhibition mechanisms. Algebraic models describing the double-reciprocal patterns obtained from such inhibition studies are presented. The virtual continuum of substrate concentrations that occurs during a progress curve experiment provides a nearly errorless set of relative concentrations that results in remarkably precise data; kinetic constant standard deviations are on the order of 0.5%. PMID:20735055

Tang, Qingxiu; Leyh, Thomas S.

2010-01-01

406

Frame Rate and Human Vision  

NASA Technical Reports Server (NTRS)

To enhance the quality of the theatre experience, the film industry is interested in achieving higher frame rates for capture and display. In this talk I will describe the basic spatio-temporal sensitivities of human vision, and how they respond to the time sequence of static images that is fundamental to cinematic presentation.

Watson, Andrew B.

2012-01-01

407

Studies with pain rating scales  

Microsoft Academic Search

Good correlation has been shown between pain scores derived from 4 different rating scales. The correlation was maintained when presentation of the scales was separated by a series of questions and by physical examination. There is good evidence that the 4 scales are measuring the same underlying pain variable as they calibrate well. There is also evidence that an 11-point

W W Downie; P A Leatham; V M Rhind; V Wright; J A Branco; J A Anderson

1978-01-01

408

Transfer Rate Report, Spring 1999.  

ERIC Educational Resources Information Center

This study attempts to discern the rate at which first-time-in-college (FTIC) Austin Community College (ACC) (Texas) students transfer to senior institutions, and which senior institutions they choose to attend. Highlights of the report include: (1) From 1990-1993, Austin Community College students transferred to four-year institutions at a higher…

Austin Community Coll., TX.

409

Fast repetition rate (FRR) flasher  

DOEpatents

A fast repetition rate (FRR) flasher is described suitable for high flash photolysis including kinetic chemical and biological analysis. The flasher includes a power supply, a discharge capacitor operably connected to be charged by the power supply, and a flash lamp for producing a series of flashes in response to discharge of the discharge capacitor. A triggering circuit operably connected to the flash lamp initially ionizes the flash lamp. A current switch is operably connected between the flash lamp and the discharge capacitor. The current switch has at least one insulated gate bipolar transistor for switching current that is operable to initiate a controllable discharge of the discharge capacitor through the flash lamp. Control means connected to the current switch for controlling the rate of discharge of the discharge capacitor thereby to effectively keep the flash lamp in an ionized state between successive discharges of the discharge capacitor. Advantageously, the control means is operable to discharge the discharge capacitor at a rate greater than 10,000 Hz and even up to a rate greater than about 250,000 Hz. 14 figs.

Kolber, Z.; Falkowski, P.

1997-02-11

410

Fed Leaves Interest Rates Alone  

NSDL National Science Digital Library

This week's In the News looks at the recent Federal Reserve Board decision to leave interest rates unchanged. The eight resources discussed provide background information on interest rates and inflation, Federal Reserve news, and current US economic data. With the stock market at record highs and global economic crises fading, the Federal Reserve Board (FRB) showed increased concern about the risk of inflation this month at a May 18, 1999 meeting of the Federal Open Market Committee (FOMC). Although committee members ultimately decided not to raise the rate at which banks lend to each other, they cited a "tight" domestic labor market and "ongoing strength in demand in excess of productivity gains" as possible reasons for future rate hikes. Wall Street reacted to the Fed news with a 100 point Dow Jones Industrial Average fall on May 18 but recovered by the end of the day down just 16.52, and many market watchers expressed optimism over the FOMC action. Irwin Kellner, chief economist at CBS.MarketWatch.com, for example, deemed the decision "great" and praised the Fed for a flexible policy that is not locked into a particular course of action should the economy change unexpectedly.

Waters, Megan.

411

CUSTOM RATES for Idaho Agricultural  

E-print Network

CUSTOM RATES for Idaho Agricultural Operations 2010­2011 by Paul E. Patterson and Kathleen Painter with the Department of Agricultural Economics and Rural Sociology, University of Idaho. Acknowledgments The authors (Jerome County). Special thanks go to the southern Idaho Cereal Schools for providing funds

O'Laughlin, Jay

412

Vector reconstruction from firing rates  

Microsoft Academic Search

In a number of systems including wind detection in the cricket, visual motion perception and coding of arm movement direction in the monkey and place cell response to position in the rat hippocampus, firing rates in a population of tuned neurons are correlated with a vector quantity. We examine and compare several methods that allow the coded vector to be

Emilio Salinas; L. F. Abbott

1994-01-01

413

NASA Human-Rating Requirements  

NASA Technical Reports Server (NTRS)

NASA's Procedural Requirements 87052B defines the Human-Rating Certification process and related technical requirements for human spaceflight programs developed by and for NASA. The document specifies Agency-level responsibilities related to the certification, processes to be established by the program, and technical requirements.

Groen, Frank; Harkins, Wil; Stamatelatos, Michael

2010-01-01

414

Supernova Rates 1 Bruno Leibundgut  

E-print Network

Supernova Rates 1 Bruno Leibundgut European Southern Observatory Karl­Schwarzschild­Strasse 2 D­85748 Garching Germany Apart from stellar winds supernovae are the only mechanism which releases stages of stellar evolution and one of the production channels of pulsars and black holes supernovae

Leibundgut, Bruno

415

Roundtable: Setting equitable water rates  

Microsoft Academic Search

This discussion, sponsored by the Management Division, was held on May 17,1982, at the AWWA Annual Conference in Miami Beach, Fla. Participants agreed that the fundamental consideration in rate-making is the cost of service. The discussion centered around methods various water utilities use to analyze the component costs that ultimately result in fair charges to all customers for water service.

Ronald D. Hardten; Elba L. Richey; Gary S. Saleba; Terry A. Scott; Charles E. Woods; Robert L. Wubbena

1983-01-01

416

Exchange Rates and Old People.  

ERIC Educational Resources Information Center

Extends earlier work on aging as a process of exchange by focusing on the issue of exchange rates and how they are negotiated. Access to power resources declines with age, placing the old person in the position of negotiating from weakness. (Author)

Dowd, James J.

1980-01-01

417

Columbus Payloads Flow Rate Anomalies  

NASA Technical Reports Server (NTRS)

The Columbus Active Thermal Control System (ATCS) is the main thermal bus for the pressurized racks working inside the European laboratory. One of the ATCS goals is to provide proper water flow rate to each payload (P/L) by controlling actively the pressure drop across the common plenum distribution piping. Overall flow measurement performed by the Water Pump Assembly (WPA) is the only flow rate monitor available at system level and is not part of the feedback control system. At rack activation the flow rate provided by the system is derived on ground by computing the WPA flow increase. With this approach, several anomalies were raised during these 3 years on-orbit, with the indication of low flow rate conditions on the European racks FSL, BioLab, EDR and EPM. This paper reviews the system and P/Ls calibration approach, the anomalies occurred, the engineering evaluation on the measurement approach and the accuracy improvements proposed, the on-orbit test under evaluation with NASA and finally discusses possible short and long term solutions in case of anomaly confirmation.

Quaranta, Albino; Bufano, Gaetana; DePalo, Savino; Holt, James M.; Szigetvari, Zoltan; Palumberi, Sergio; Hinderer, S.

2011-01-01

418

Divergent Thinking and Interview Ratings  

ERIC Educational Resources Information Center

This study examined divergent thinking (DT) test scores of applicants taking part in a selection procedure for an undergraduate psychology degree (N = 370). Interviewers made six specific (creative intelligence, motivation, work habits, emotional stability, sociability, and social responsibility) and one overall recommendation rating on each…

Batey, Mark; Rawles, Richard; Furnham, Adrian

2009-01-01

419

1993 Wholesale Power and Transmission Rate Schedules.  

SciTech Connect

Bonneville Power Administration 1993 Wholesale Power Rate Schedules and General Rate Schedule Provisions and 1993 Transmission Rate Schedules and General Transmission Rate Schedule Provisions, contained herein, were approved on an interim basis effective October 1, 1993. These rate schedules and provisions were approved by the Federal Energy Commission, United States Department of Energy, in September, 1993. These rate schedules and provisions supersede the Administration`s Wholesale Power Rate Schedules and General Rate Schedule Provisions and Transmission Rate Schedules and General Transmission Rate Schedule Provisions effective October 1, 1991.

US Bonneville Power Administration

1993-10-01

420

Sensor for Injection Rate Measurements  

PubMed Central

A vast majority of the medium and high speed Diesel engines are equipped with multi-hole injection nozzles nowadays. Inaccuracies in workmanship and changing hydraulic conditions in the nozzles result in differences in injection rates between individual injection nozzle holes. The new deformational measuring method described in the paper allows injection rate measurement in each injection nozzle hole. The differences in injection rates lead to uneven thermal loads of Diesel engine combustion chambers. All today known measuring method, such as Bosch and Zeuch give accurate results of the injection rate in diesel single-hole nozzles. With multihole nozzles they tell us nothing about possible differences in injection rates between individual holes of the nozzle. At deformational measuring method, the criterion of the injected fuel is expressed by the deformation of membrane occurring due to the collision of the pressure wave against the membrane. The pressure wave is generated by the injection of the fuel into the measuring space. For each hole of the nozzle the measuring device must have a measuring space of its own into which fuel is injected as well as its measuring membrane and its own fuel outlet. During measurements procedure the measuring space must be filled with fuel to maintain an overpressure of 5 kPa. Fuel escaping from the measuring device is conducted into the graduated cylinders for measuring the volumetric flow through each hole of the nozzle.The membrane deformation is assessed by strain gauges. They are glued to the membrane and forming the full Wheatstone's bridge. We devoted special attention to the membrane shape and temperature compensation of the strain gauges.

Marcic, Milan

2006-01-01

421

Crystal Size and Cooling Rate  

NSDL National Science Digital Library

This activity relates to the process of igneous rock formation by the cooling of magma. It can be used to illustrate how the rate at which molten rock cools affects the size of the crystals that form within the solid rock - rapid cooling producing small crystals, slower cooling producing larger ones. Hot, saturated solutions of lead iodide are cooled at different rates. The solution that cools faster produces smaller crystals. Students relate this to samples of rhyolite and granite and discover that the intrusive igneous rock (the granite) has cooled slowly from magma, and the rhyolite lava (extrusive igneous rock) has cooled very quickly. This leads to a fuller explanation of the terms intrusive and extrusive. The site also has an alternative demonstration in which melted Salol is placed on hot and cold glass slides with similar results.

422

Solar PV- Standby Rate Estimator  

NSDL National Science Digital Library

The Advanced Technology Environmental and Energy Center (ATEEC) provides this spreadsheet to be used in conjunction with the Standby Rate Manual (available for download here). The document aims to help businesses analyze the potential energy savings of implementing an on site combined heat and power (CHP) system. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

423

Instructor Reputation and Teacher Ratings  

NSDL National Science Digital Library

Created by David M. Lane of Rice University, this case study covers concepts including: boxplots, stem and leaf displays, two-sample t tests, and analysis of variance. It also assesses the question, "Does an instructor's reputation affect ratings of the instructor's lecture?" The author divides the lesson in these way: background, experimental design, descriptive statistics, inferential statistics, instructions for SPSS and the raw data set. This is a carefully designed case study which employs many methods important to statistical research.

Lane, David M.

424

Low nutation-rate dampers  

NASA Technical Reports Server (NTRS)

Mission requirements plus spacecraft weight and power constraints often reduce the excitation frequency of a nutation damper below 1 cpm. Since attitude stability is determined by damper performance, maximum effectiveness at low rates is demanded. Presented are design considerations that low-frequency dampers require, along with descriptions of two low-frequency systems: the Direct Measurement Explorer 1 and the Small Astronomy Satellite A (SAS-A).

Tossman, B. E.

1971-01-01

425

Quantification of through drying rate data  

SciTech Connect

For through drying there are three distinct drying periods, increasing rate, constant rate and falling rate. The increasing rate period is so important that nearly half of the drying is completed in this period only. A drying rate--moisture content relationship for this period was obtained based on theoretical analysis. It was verified with experimental data. A quantitative representation of the complete drying rate curve was established using this relationship and a modified power law equation for the falling rate period drying rate--moisture content relation. It needs five parameters to quantify the through drying from wet to dry: moisture content at the end of the increasing rate period; exponent for the drying rate--moisture relationship during the increasing rate period; constant drying rate; critical moisture content and the power-law exponent for the falling rate period.

Chen, G.; Douglas, W.J.M.

1999-09-01

426

Estimating initial epidemic growth rates.  

PubMed

The initial exponential growth rate of an epidemic is an important measure of disease spread, and is commonly used to infer the basic reproduction number [Formula: see text]. While modern techniques (e.g., MCMC and particle filtering) for parameter estimation of mechanistic models have gained popularity, maximum likelihood fitting of phenomenological models remains important due to its simplicity, to the difficulty of using modern methods in the context of limited data, and to the fact that there is not always enough information available to choose an appropriate mechanistic model. However, it is often not clear which phenomenological model is appropriate for a given dataset. We compare the performance of four commonly used phenomenological models (exponential, Richards, logistic, and delayed logistic) in estimating initial epidemic growth rates by maximum likelihood, by fitting them to simulated epidemics with known parameters. For incidence data, both the logistic model and the Richards model yield accurate point estimates for fitting windows up to the epidemic peak. When observation errors are small, the Richards model yields confidence intervals with better coverage. For mortality data, the Richards model and the delayed logistic model yield the best growth rate estimates. We also investigate the width and coverage of the confidence intervals corresponding to these fits. PMID:24272389

Ma, Junling; Dushoff, Jonathan; Bolker, Benjamin M; Earn, David J D

2014-01-01

427

12 CFR 327.4 - Assessment rates.  

Code of Federal Regulations, 2013 CFR

...institution cannot request review through this process of the CAMELS ratings assigned by its primary federal regulator or...or state authority of its supervisory rating (even when the CAMELS component ratings have not been disclosed to the...

2013-01-01

428

12 CFR 327.4 - Assessment rates.  

Code of Federal Regulations, 2012 CFR

...institution cannot request review through this process of the CAMELS ratings assigned by its primary federal regulator or...or state authority of its supervisory rating (even when the CAMELS component ratings have not been disclosed to the...

2012-01-01

429

12 CFR 327.4 - Assessment rates.  

Code of Federal Regulations, 2010 CFR

...institution cannot request review through this process of the CAMELS ratings assigned by its primary federal regulator...or state authority of its supervisory rating (even when the CAMELS component ratings have not been disclosed to the...

2010-01-01

430

12 CFR 327.4 - Assessment rates.  

Code of Federal Regulations, 2011 CFR

...institution cannot request review through this process of the CAMELS ratings assigned by its primary federal regulator...or state authority of its supervisory rating (even when the CAMELS component ratings have not been disclosed to the...

2011-01-01

431

12 CFR 327.4 - Assessment rates.  

Code of Federal Regulations, 2014 CFR

...institution cannot request review through this process of the CAMELS ratings assigned by its primary federal regulator or...or state authority of its supervisory rating (even when the CAMELS component ratings have not been disclosed to the...

2014-01-01

432

46 CFR 183.230 - Temperature ratings.  

Code of Federal Regulations, 2014 CFR

... 2014-10-01 2014-10-01 false Temperature ratings. 183.230 Section 183.230 ...INSTALLATION General Requirements § 183.230 Temperature ratings. Temperature ratings of electrical equipment must meet...

2014-10-01

433

46 CFR 183.230 - Temperature ratings.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Temperature ratings. 183.230 Section 183.230 ...INSTALLATION General Requirements § 183.230 Temperature ratings. Temperature ratings of electrical equipment must meet...

2011-10-01

434

46 CFR 183.230 - Temperature ratings.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 2010-10-01 false Temperature ratings. 183.230 Section 183.230 ...INSTALLATION General Requirements § 183.230 Temperature ratings. Temperature ratings of electrical equipment must meet...

2010-10-01

435

46 CFR 183.230 - Temperature ratings.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 false Temperature ratings. 183.230 Section 183.230 ...INSTALLATION General Requirements § 183.230 Temperature ratings. Temperature ratings of electrical equipment must meet...

2013-10-01

436

46 CFR 183.230 - Temperature ratings.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Temperature ratings. 183.230 Section 183.230 ...INSTALLATION General Requirements § 183.230 Temperature ratings. Temperature ratings of electrical equipment must meet...

2012-10-01

437

24 CFR 597.103 - Poverty rate.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 2010-04-01 false Poverty rate. 597.103 Section 597.103 Housing...DESIGNATIONS Area Requirements § 597.103 Poverty rate. (a) General. The poverty rate shall be established in accordance...

2010-04-01

438

24 CFR 597.103 - Poverty rate.  

Code of Federal Regulations, 2011 CFR

...3 2011-04-01 2010-04-01 true Poverty rate. 597.103 Section 597.103 Housing...DESIGNATIONS Area Requirements § 597.103 Poverty rate. (a) General. The poverty rate shall be established in accordance...

2011-04-01

439

24 CFR 597.103 - Poverty rate.  

Code of Federal Regulations, 2014 CFR

...3 2014-04-01 2013-04-01 true Poverty rate. 597.103 Section 597.103 Housing...DESIGNATIONS Area Requirements § 597.103 Poverty rate. (a) General. The poverty rate shall be established in accordance...

2014-04-01

440

24 CFR 597.103 - Poverty rate.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 2012-04-01 false Poverty rate. 597.103 Section 597.103 Housing...DESIGNATIONS Area Requirements § 597.103 Poverty rate. (a) General. The poverty rate shall be established in accordance...

2012-04-01

441

24 CFR 597.103 - Poverty rate.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Poverty rate. 597.103 Section 597.103 Housing...DESIGNATIONS Area Requirements § 597.103 Poverty rate. (a) General. The poverty rate shall be established in accordance...

2013-04-01

442

7 CFR 947.247 - Assessment rate.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Assessment rate. 947.247 Section 947.247 Agriculture Regulations of the Department of Agriculture...MALHEUR COUNTY Reports Assessment Rates § 947.247 Assessment rate. On and after July 1,...

2010-01-01

443

7 CFR 981.343 - Assessment rate.  

Code of Federal Regulations, 2010 CFR

...Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Assessment Rates § 981.343 Assessment...assessment rate of $0.030 per pound is established for California almonds. Of the $0.030 assessment rate, 60 percent per...

2010-01-01

444

20 CFR 345.307 - Rate protest.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Rate protest. 345.307 Section...REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT INSURANCE ACT EMPLOYERS...CONTRIBUTION REPORTS Contribution Rates § 345.307 Rate protest. (a) Request...

2010-04-01

445

Event rates for WIMP detection  

SciTech Connect

The event rates for the direct detection of dark matter for various types of WIMPs are presented. In addition to the neutralino of SUSY models, we considered other candidates (exotic scalars as well as particles in Kaluza-Klein and technicolour theories) with masses in the TeV region. Then one finds reasonable branching ratios to excited states. Thus the detection of the WIMP can be made not only by recoil measurements, by measuring the de-excitation {gamma}-rays as well.

Vergados, J. D. [University of Ioannina, Ioannina, Gr 45110 (Greece); Moustakidis, Ch. C.; Oikonomou, V. [Department of Theoretical Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

2006-11-28

446

Energy Management Through Innovative Rates  

E-print Network

the exception of the recent buildup of the Strategic Petroleum Reserve, the United States is no better prepared to deal with significant disruptions in oil imports than it was during the 1973 oil embargo." The study stresses the importance of strategic... levels of consumption for 500 years or more. Petroleum reserves are considered to be adequate for the next 50 to 75 years. (See Figure 1) However, growth in the rate of fuel consumption could mean current fuel supplies may be exhausted within 20...

Williams, M. L.

1982-01-01

447

78 FR 283 - 2013 Rate Changes for the Basetime, Overtime, Holiday, and Laboratory Services Rates  

Federal Register 2010, 2011, 2012, 2013, 2014

...allowance rate) = $83.54. Laboratory Services Rate = The quotient...The calculation for the 2013 laboratory services rate per hour per...overtime, holiday, and laboratory services rates formulas...Register_Notices/index.asp. FSIS will also make...

2013-01-03

448

Rating the Size of Earthquakes  

NSDL National Science Digital Library

This report describes how the work of K. Wadati, Charles F. Richter, Harry O. Wood, and Beno Gutenberg resulted in a way of rating earthquakes in southern California according to an instrumental analysis of the amount of energy they released in the form of seismic waves. This work resulted in the first use of the term "magnitude" for describing the amount of energy released by an earthquake, and in the development of the now-famous Richter Scale for quantifying earthquake magnitudes. Topics include the original definition of Richter magnitude and a brief synopsis of how Richter used earthquake data from southern California to graphically represent trace amplitude and develop a table of values that could be used to calculate magnitudes.

449

Exchange rate expectations of chartists and fundamentalists  

Microsoft Academic Search

This paper provides novel evidence on exchange rate expectations of both chartists and fundamentalists separately. These groups indeed form expectations differently. Chartists change their expectations more often; however, all professionals' expectations vary considerably as they generally follow strong exchange rate trends. In line with non-linear exchange rate-modeling, professionals expect mean reversion only if exchange rates deviate much from PPP. Chartists

Christian D. Dick; Lukas Menkhoff

2012-01-01

450

29 CFR 1620.12 - Wage “rate  

Code of Federal Regulations, 2011 CFR

...includes the rate at which overtime compensation or other special remuneration is paid as well as the rate at which straight time compensation...higher wage rate is paid to one gender than the other for the performance of equal work, the higher rate serves as a wage...

2011-07-01

451

Partitioning the Variation in Mammalian Substitution Rates  

Microsoft Academic Search

We have used analysis of variance to partition the variation in synonymous and amino acid substitution rates between three effects (gene, lineage, and a gene-by-lineage interaction) in mammalian nuclear and mitochondrial genes. We find that gene effects are stronger for amino acid substitution rates than for synonymous substitution rates and that lineage effects are stronger for synonymous substitution rates than

Nick G. C. Smith; Adam Eyre-Walker

2003-01-01

452

78 FR 44459 - Rate Regulation Reforms  

Federal Register 2010, 2011, 2012, 2013, 2014

...Rate, as published in the Wall Street Journal). Part V describes the concern...Prime Rate as published by The Wall Street Journal. The rate levels will be determined...Prime Rate as published by The Wall Street Journal in effect on the date the...

2013-07-24

453

77 FR 44571 - Rate Regulation Reforms  

Federal Register 2010, 2011, 2012, 2013, 2014

...Rate, as published in The Wall Street Journal. Additional information is...Prime Rate as Published by The Wall Street Journal. The rate levels will be determined...Prime Rate as published by The Wall Street Journal in effect on the date the...

2012-07-30

454

Feedback Functions, Optimization, and the Relation of Response Rate to Reinforcer Rate  

ERIC Educational Resources Information Center

The present experiment arranged a series of inverted U-shaped feedback functions relating reinforcer rate to response rate to test whether responding was consistent with an optimization account or with a one-to-one relation of response rate to reinforcer rate such as linear system theory's rate equation or Herrnstein's hyperbola. Reinforcer rate…

Soto, Paul L.; McDowell, Jack J.; Dallery, Jesse

2006-01-01

455

PROPERTY-LIABILITY INSURER FINANCIAL STRENGTH RATINGS: DIFFERENCES ACROSS RATING AGENCIES  

Microsoft Academic Search

Regulators, investors, consumers, and insurance brokers use insurer finan- cial strength ratings to evaluate the insolvency risk of insurers. This article investigates the factors influencing the decision to obtain a rating or mul- tiple ratings, the determinants of ratings for the three major insurer rating agencies, and reasons for differences in ratings across agencies. This study indicates that insurers obtain

Steven W. Pottier; David W. Sommer

456

What does Self Rated Mental Health Represent  

PubMed Central

Background Unlike the widely used self rated health, the self rated mental health was found unsuitable as a proxy for mental illness. This paper analyses the relationships between the self ratings of physical health, mental health and overall health, and their association of with the objective indicators for physical and mental health. Design and methods The study is a secondary analysis of data from a nationwide representative sample of the non-institutionalized adult residents of Israel in 2003 that was collected via computer-assisted personal interview methods [n=4859]. Results The self rated physical health and the self rated mental health were strongly related to each other yet the self rated mental health was not related to chronic physical conditions and the self rated physical health was not related to mental disorders. In a multiple logistic regression analysis, those with positive self rated mental health had 93 times the odds of reporting positive overall health whereas those with positive self rated physical health had 40 times the odds of reporting positive overall health. Conclusions The self rating of mental health presents a qualitatively different dimension from mental illness. The self rated mental health is two times more important than the self rated physical health in predicting the self rated overall health Significance for public health The present study is an original study on the self rated physical, mental and overall health measures. Because of the wide range of associations with other health indicators, and the simplicity with which they are collected, self-rated health measures are widely used in large population surveys. The present study questions the automatic assumption that the self rated mental health functions as a proxy measure of psychiatric morbidity, and suggests that the self rated mental health is more closely related to subjective well-being. The results show that self rated mental health predicts self rated general health better than self rated physical health. PMID:25553310

Levinson, Daphna; Kaplan, Giora

2014-01-01

457

Hypernatremia: Correction Rate and Hemodialysis  

PubMed Central

Severe hypernatremia is defined as serum sodium levels above 152?mEq/L, with a mortality rate ?60%. 85-year-old gentleman was brought to the emergency room with altered level of consciousness after refusing to eat for a week at a skilled nursing facility. On admission patient was nonverbal with stable vital signs and was responsive only to painful stimuli. Laboratory evaluation was significant for serum sodium of 188?mmol/L and water deficit of 12.0?L. Patient was admitted to medicine intensive care unit and after inadequate response to suboptimal fluid repletion, hemodialysis was used to correct hypernatremia. Within the first fourteen hours, sodium concentration only changed 1?mEq/L with a fluid repletion; however, the concentration dropped greater than 20?mEq/L within two hours during hemodialysis. Despite such a drastic drop in sodium concentration, patient did not develop any neurological sequela and was at baseline mental status at the time of discharge. PMID:25431600

Nur, Saima; Nur, Saadia; Boroujerdi, Hassan

2014-01-01

458

Ratings of kinetic depth in multidot displays.  

PubMed

Subjects saw kinetic depth displays whose shape (sphere or cylinder) was defined by luminous dots distributed randomly on the surface or in the volume of the object. Subjects rated perceived 3-D depth, rigidity, and coherence. Despite individual differences, all 3 ratings increased with the number of dots. Dots in the volume yielded ratings equal to or greater than surface dots. Each rating varied with 3 of 4 factors (shape, distribution, numerosity, and perspective), but the ratings either between trials or between conditions were often uncorrelated. Object shape affected rigidity but not depth ratings. Veridically perceived polar displays had slightly lower rigidity but higher depth ratings than parallel projection displays. (Reversed polar displays were always grossly nonrigid.) The interaction of ratings and stimulus parameters requires theories and experiments in which different KDE ratings are not treated interchangeably. PMID:2531213

Dosher, B A; Landy, M S; Sperling, G

1989-11-01

459

1996 Wholesale Power and Transmission Rate Schedules.  

SciTech Connect

Bonneville Power Administration`s (BPA) 1996 Wholesale Power Rate Schedules, 1996 Ancillary Products and Services Rate Schedule, 1996 Transmission Rate Schedules, and General Rate Schedule Provisions, contained herein, were approved on an interim basis effective October 1, 1996. These rate schedules and provisions were approved by the Federal Energy Regulatory Commission (FERC), United States Department of Energy, in September 1996 (Docket Nos EF96-2011-000 and EF96f-2021-000). These rate schedules and General Rate Schedule Provisions were approved on a final basis by the FERC July 30, 1997, in Dept. of Energy--Bonneville Power Administration, Docket Nos. EF96-2011-000 and EF96-2021-000. Except as noted elsewhere, these 1996 rate schedules and provisions supersede BPA`s Wholesale Power Rate Schedules and General Rate Schedule Provisions, and Transmission Rate Schedules and General Transmission Rate Schedule Provisions, effective October 1, 1995. These rate schedules and general rate schedule provisions include all errata.

United States. Bonneville Power Administration.

1996-10-01

460

Dependence of bacterial chemotaxis on gradient shape and adaptation rate.  

PubMed

Simulation of cellular behavior on multiple scales requires models that are sufficiently detailed to capture central intracellular processes but at the same time enable the simulation of entire cell populations in a computationally cheap way. In this paper we present RapidCell, a hybrid model of chemotactic Escherichia coli that combines the Monod-Wyman-Changeux signal processing by mixed chemoreceptor clusters, the adaptation dynamics described by ordinary differential equations, and a detailed model of cell tumbling. Our model dramatically reduces computational costs and allows the highly efficient simulation of E. coli chemotaxis. We use the model to investigate chemotaxis in different gradients, and suggest a new, constant-activity type of gradient to systematically study chemotactic behavior of virtual bacteria. Using the unique properties of this gradient, we show that optimal chemotaxis is observed in a narrow range of CheA kinase activity, where concentration of the response regulator CheY-P falls into the operating range of flagellar motors. Our simulations also confirm that the CheB phosphorylation feedback improves chemotactic efficiency by shifting the average CheY-P concentration to fit the motor operating range. Our results suggest that in liquid media the variability in adaptation times among cells may be evolutionary favorable to ensure coexistence of subpopulations that will be optimally tactic in different gradients. However, in a porous medium (agar) such variability appears to be less important, because agar structure poses mainly negative selection against subpopulations with low levels of adaptation enzymes. RapidCell is available from the authors upon request. PMID:19096502

Vladimirov, Nikita; Løvdok, Linda; Lebiedz, Dirk; Sourjik, Victor

2008-12-01

461

Shapley ratings in brain networks.  

PubMed

Recent applications of network theory to brain networks as well as the expanding empirical databases of brain architecture spawn an interest in novel techniques for analyzing connectivity patterns in the brain. Treating individual brain structures as nodes in a directed graph model permits the application of graph theoretical concepts to the analysis of these structures within their large-scale connectivity networks. In this paper, we explore the application of concepts from graph and game theory toward this end. Specifically, we utilize the Shapley value principle, which assigns a rank to players in a coalition based upon their individual contributions to the collective profit of that coalition, to assess the contributions of individual brain structures to the graph derived from the global connectivity network. We report Shapley values for variations of a prefrontal network, as well as for a visual cortical network, which had both been extensively investigated previously. This analysis highlights particular nodes as strong or weak contributors to global connectivity. To understand the nature of their contribution, we compare the Shapley values obtained from these networks and appropriate controls to other previously described nodal measures of structural connectivity. We find a strong correlation between Shapley values and both betweenness centrality and connection density. Moreover, a stepwise multiple linear regression analysis indicates that approximately 79% of the variance in Shapley values obtained from random networks can be explained by betweenness centrality alone. Finally, we investigate the effects of local lesions on the Shapley ratings, showing that the present networks have an immense structural resistance to degradation. We discuss our results highlighting the use of such measures for characterizing the organization and functional role of brain networks. PMID:18974797

Kötter, Rolf; Reid, Andrew T; Krumnack, Antje; Wanke, Egon; Sporns, Olaf

2007-01-01

462

Shapley Ratings in Brain Networks  

PubMed Central

Recent applications of network theory to brain networks as well as the expanding empirical databases of brain architecture spawn an interest in novel techniques for analyzing connectivity patterns in the brain. Treating individual brain structures as nodes in a directed graph model permits the application of graph theoretical concepts to the analysis of these structures within their large-scale connectivity networks. In this paper, we explore the application of concepts from graph and game theory toward this end. Specifically, we utilize the Shapley value principle, which assigns a rank to players in a coalition based upon their individual contributions to the collective profit of that coalition, to assess the contributions of individual brain structures to the graph derived from the global connectivity network. We report Shapley values for variations of a prefrontal network, as well as for a visual cortical network, which had both been extensively investigated previously. This analysis highlights particular nodes as strong or weak contributors to global connectivity. To understand the nature of their contribution, we compare the Shapley values obtained from these networks and appropriate controls to other previously described nodal measures of structural connectivity. We find a strong correlation between Shapley values and both betweenness centrality and connection density. Moreover, a stepwise multiple linear regression analysis indicates that approximately 79% of the variance in Shapley values obtained from random networks can be explained by betweenness centrality alone. Finally, we investigate the effects of local lesions on the Shapley ratings, showing that the present networks have an immense structural resistance to degradation. We discuss our results highlighting the use of such measures for characterizing the organization and functional role of brain networks. PMID:18974797

Kötter, Rolf; Reid, Andrew T.; Krumnack, Antje; Wanke, Egon; Sporns, Olaf

2007-01-01

463

The black market exchange rate vs. the official rate in testing PPP: Which rate fosters the adjustment process?  

Microsoft Academic Search

In testing the purchasing power parity theory (PPP) researchers hardly pay attention to the speed with which the exchange rate adjusts to a change in relative prices. In this paper we show that the speed of adjustment is faster when the black market exchange rate is used in testing the PPP as compared to the official exchange rate. This could

Mohsen Bahmani-Oskooee; Altin Tankui

2008-01-01

464

Rate of Nucleation in Condensed Systems  

Microsoft Academic Search

On the basis of the nucleation theory developed by Volmer, Becker, and co-workers, and the theory of absolute reaction rates, an expression is derived for the absolute rate of nucleation in condensed systems.

D. Turnbull; J. C. Fisher

1949-01-01

465

7 CFR 1435.101 - Loan rates.  

Code of Federal Regulations, 2012 CFR

...AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS SUGAR PROGRAM Sugar Loan Program § 1435.101 Loan rates. (a) The national average loan rate for raw cane sugar produced from domestically grown sugarcane...

2012-01-01

466

7 CFR 1435.101 - Loan rates.  

Code of Federal Regulations, 2014 CFR

...AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS SUGAR PROGRAM Sugar Loan Program § 1435.101 Loan rates. (a) The national average loan rate for raw cane sugar produced from domestically grown sugarcane...

2014-01-01

467

Cervical Cancer Rates by Race and Ethnicity  

MedlinePLUS

... Fighting Cervical Cancer Worldwide Stay Informed Rates by Race and Ethnicity for Other Kinds of Cancer All ... Skin Uterine Cancer Home Cervical Cancer Rates by Race and Ethnicity Language: English Español (Spanish) Share Compartir ...

468

Breast Cancer Rates by Race and Ethnicity  

MedlinePLUS

... Right to Know Campaign Stay Informed Rates by Race and Ethnicity for Other Kinds of Cancer All ... Skin Uterine Cancer Home Breast Cancer Rates by Race and Ethnicity Language: English Español (Spanish) Share Compartir ...

469

Prostate Cancer Rates by Race and Ethnicity  

MedlinePLUS

... Cancer Screening Discussions Partners Stay Informed Rates by Race and Ethnicity for Other Types of Cancer All ... Skin Uterine Cancer Home Prostate Cancer Rates by Race and Ethnicity Language: English Español (Spanish) Share Compartir ...

470

42 CFR 405.2464 - Payment rate.  

Code of Federal Regulations, 2014 CFR

...the rate to assure that payments approximate actual allowable...Determination of the payment rate for FQHCs billing under the prospective payment system. (1) A per diem...furnishes services to a new patient, as defined...

2014-10-01

471

7 CFR 755.7 - Transportation rates.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Transportation rates. 755.7 Section 755... SPECIAL PROGRAMS REIMBURSEMENT TRANSPORTATION COST PAYMENT PROGRAM FOR GEOGRAPHICALLY...FARMERS AND RANCHERS § 755.7 Transportation rates. (a) Payments may be...

2011-01-01

472

7 CFR 755.7 - Transportation rates.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Transportation rates. 755.7 Section 755... SPECIAL PROGRAMS REIMBURSEMENT TRANSPORTATION COST PAYMENT PROGRAM FOR GEOGRAPHICALLY...FARMERS AND RANCHERS § 755.7 Transportation rates. (a) Payments may be...

2013-01-01

473

7 CFR 755.7 - Transportation rates.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Transportation rates. 755.7 Section 755... SPECIAL PROGRAMS REIMBURSEMENT TRANSPORTATION COST PAYMENT PROGRAM FOR GEOGRAPHICALLY...FARMERS AND RANCHERS § 755.7 Transportation rates. (a) Payments may be...

2012-01-01

474

7 CFR 755.7 - Transportation rates.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Transportation rates. 755.7 Section 755... SPECIAL PROGRAMS REIMBURSEMENT TRANSPORTATION COST PAYMENT PROGRAM FOR GEOGRAPHICALLY...FARMERS AND RANCHERS § 755.7 Transportation rates. (a) Payments may be...

2014-01-01

475

Rate Setting for Small Water Systems  

E-print Network

-funded center at Boise State University has developed a free software program (?RATE Checkup?) that helps small water systems set rates and prepare budget forecasts. The center that serves Texas is locat- ed at New Mexico Tech University. In addition...

Dozier, Monty; Theodori, Gene L.; Jensen, Ricard

2007-03-28

476

7 CFR 959.237 - Assessment rate.  

Code of Federal Regulations, 2012 CFR

...Nuts), DEPARTMENT OF AGRICULTURE ONIONS GROWN IN SOUTH TEXAS Assessment Rates § 959.237 Assessment rate. On...of $0.025 per 50-pound equivalent is established for South Texas onions. [74 FR 38508, Aug. 4,...

2012-01-01

477

7 CFR 959.237 - Assessment rate.  

Code of Federal Regulations, 2011 CFR

...Nuts), DEPARTMENT OF AGRICULTURE ONIONS GROWN IN SOUTH TEXAS Assessment Rates § 959.237 Assessment rate. On...of $0.025 per 50-pound equivalent is established for South Texas onions. [74 FR 38508, Aug. 4,...

2011-01-01

478

7 CFR 959.237 - Assessment rate.  

Code of Federal Regulations, 2010 CFR

...Nuts), DEPARTMENT OF AGRICULTURE ONIONS GROWN IN SOUTH TEXAS Assessment Rates § 959.237 Assessment rate. On...of $0.025 per 50-pound equivalent is established for South Texas onions. [74 FR 38508, Aug. 4,...

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